JP4858947B2 - Image display device, electronic apparatus, liquid crystal television device, liquid crystal monitor device, image display method, display control program, and recording medium - Google Patents

Description

  The present invention relates to an image display device using a hold-type display element such as a liquid crystal display element or an EL display element, an electronic device, a liquid crystal television device, a liquid crystal monitor device, an image display method, and an image display method using the same. The present invention relates to a display control program to be executed by a computer and a computer-readable recording medium on which the program is recorded.

  Conventionally, as an image display device, a hold-type image using an impulse-type image display device such as a CRT (cathode ray tube) or a film projector and a hold-type display device such as the above-described liquid crystal display device or EL display device. Broadly divided into display devices.

  In the impulse-type image display device, a lighting period in which an image is displayed and a light-out period in which no image is displayed are alternately repeated. It is said that the human eye perceives brightness that is time-integrated over a period of several frames as a brightness change actually displayed on the screen. For this reason, even when viewing an image display device in which luminance changes in a short period of less than one frame, such as an impulse-type image display device that is repeatedly turned on and off, an image can be observed without a sense of incongruity.

  FIG. 46 shows how luminance changes over time on one horizontal line in a screen when displaying an image in which an object moves horizontally on a stationary background in a conventional impulse-type image display device. FIG. In FIG. 46, the horizontal axis represents the state of luminance in the horizontal direction (horizontal pixel position) on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  In the conventional impulse-type image display device shown in FIG. 46, there is an image lighting period T102 in which an updated image is displayed at the beginning of one frame period T101, which is a period in which the image is updated, and then the next frame. The image extinction period T103 in which the image is not displayed and has the minimum luminance continues until the image is updated.

  When attention is paid to the display state for one horizontal line, there is a display unit A of an object that is sandwiched by a display unit B of a stationary background, and the display unit A of the object moves to the right every time the frame is updated. .

  At this time, for the observer watching the moving object display A, the eye moves in the direction indicated by the oblique thick line arrow in FIG. 46 in order to follow the object display A. The time integral value of the luminance change in the trajectory direction in which the object has moved is perceived by human eyes as brightness.

  FIG. 47 is a diagram showing how the brightness distribution looks to the observer who has watched the moving object when the video as shown in FIG. 46 is displayed.

  In FIG. 47, in the impulse-type image display device, most of the period from the image update of one frame to the image update of the next frame is the extinguishing period T103. Since this extinguishing period T103 has sufficiently small luminance, it does not contribute to the value of time integration of luminance on the vertical axis. As a result, the observer can clearly see the difference in brightness at the boundary between the stationary background and the moving object, so that the background and the object can be clearly distinguished.

  It is said that the hold-type image display device is inferior in moving image quality as compared with such an impulse-type display device. This will be described in detail below.

  FIG. 48 is a diagram showing luminance with the passage of time on one horizontal line in a screen when displaying an image in which an object moves horizontally on a stationary background in a general conventional hold-type image display device. It is a figure which shows the mode of a change. In FIG. 48, the horizontal axis represents the state of luminance in the horizontal direction (horizontal pixel position) on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  The conventional hold-type image display device shown in FIG. 48 is different from the conventional impulse-type image display device shown in FIG. 46 in that one frame period T101 is the image lighting period T102 and the extinguishing period T103 is the same. It is not provided.

  FIG. 49 is a diagram showing how the brightness distribution looks to an observer who has watched a moving object when the video as shown in FIG. 48 is displayed.

  As shown in FIG. 49, in a general conventional hold-type image display device, since one frame period T101 is the image lighting period T102, when an image is updated in a certain frame, the image is displayed in the next frame. Until it is updated, the object remains in that position and displayed. For this reason, in the time integration of the luminance change in the direction of the trajectory in which the object has moved, the difference in brightness does not appear clearly at the boundary between the stationary background and the moving object, and it appears as motion blur to the observer's eyes. End up. This contributes to the deterioration of moving image quality in a general conventional hold-type image display device.

  In order to improve the deterioration of the moving image quality in such a hold-type image display device, there is a method of reducing the display lighting period to about half and providing a minimum luminance display period (hereinafter referred to as a black insertion method).

  FIG. 50 is a diagram illustrating luminance with the passage of time on one horizontal line in a screen when displaying an image in which an object moves horizontally on a stationary background in a hold-type image display device adopting a black insertion method. It is a figure which shows the mode of a change. In FIG. 50, the horizontal axis shows the state of luminance in the horizontal direction (horizontal pixel position) on the screen, and the vertical axis shows the passage of time, representing screen display for a three-frame period.

  As shown in FIG. 50, the conventional hold-type image display device adopting the black insertion method is different from the general hold-type image display device shown in FIG. This is that a turn-off period (minimum luminance display period; black insertion period) T103 is provided for the / 2 frame period.

  FIG. 51 is a diagram showing how the brightness distribution looks for an observer who has watched a moving object when an image as shown in FIG. 50 is displayed.

  As shown in FIG. 51, it can be seen that the conventional hold-type image display device employing the black insertion method has improved motion blur compared to the general conventional hold-type display device shown in FIG.

  However, the conventional hold-type image display device adopting this black insertion method includes a minimum luminance (black) display period (light-out period) even when the maximum gradation level is displayed. For this reason, the maximum luminance perceived by the observer is halved compared to a general conventional hold-type image display device in which no minimum luminance display period is provided.

  In particular, when a self-luminous element such as an EL display element is used, it is inevitable that the maximum luminance is reduced as compared with a general hold-type image display device in which a minimum luminance display period is not provided.

  On the other hand, when a transmissive display element such as a transmissive liquid crystal display element is used, the minimum luminance display period (black insertion period) is provided by increasing the luminance of the backlight by the black insertion period. A method of securing the maximum luminance comparable to that of a general hold-type image display device that has not been considered is also considered.

  However, in this case, there is a problem that the power consumption of the backlight increases. Further, even when the minimum luminance (black) is displayed, since the backlight light can pass through the display element, it is the same level as the hold-type image display device in which the minimum luminance display period (black insertion period) is not provided. There is a problem that the minimum brightness of the image cannot be ensured and the contrast is lowered.

  Therefore, while ensuring the maximum luminance of the same level as that of a general hold-type image display device in which the minimum luminance display period (black insertion period) is not provided, the moving image quality is improved by improving motion blur as much as possible. As a method, for example, an image display method as shown in claims 27 to 41 of Patent Document 1 has been proposed. A specific display driving method and a gradation level image signal supplying method are described in Patent Document 1. This is described in detail in the first seventh embodiment.

  In the image display method proposed in Patent Document 1, image display is performed using two subframe periods of the first half and the second half of an input image signal for one frame. When the gradation level of the input image signal is 0% or more and less than 50%, an image signal having a gradation level of 0% to 100% is supplied in the first half subframe period, and in the second half subframe period. An image signal having a gradation level of 0% is supplied. When the input gradation level is 50% or more and 100% or less, an image signal having a gradation level of 0% to 100% is supplied in the first half subframe period and 100% in the second half subframe period. A gradation level image signal is supplied.

  FIG. 52 shows the time on one horizontal line in the screen when displaying an image in which an object moves horizontally on a stationary background in the conventional hold-type image display device disclosed in Patent Document 1. It is a figure which shows the mode of the brightness | luminance change accompanying progress. In FIG. 52, the horizontal axis indicates the state of luminance in the horizontal direction on the screen, and the vertical axis indicates the passage of time, representing screen display for a three-frame period.

  The conventional hold type image display device shown in FIG. 52 is different from the general hold type image display device shown in FIG. 48 in that two subframe periods T201 and T202 are provided in one frame period T101. It is.

  This will be described in more detail. As shown in FIG. 52, in the stationary background display section B, the gradation level of the input image signal is small, so that it is lit only in the first half subframe period T201. The sub-frame period T202 is turned off (0%). On the other hand, in the display portion A of the moving object, the gradation level of the input image signal is sufficiently high, so that it is lit at the maximum luminance (100%) in the second half subframe period T202 and 0% in the first half subframe period T201. Illuminated (20%) as an image signal having a gradation level of ˜100%. The number in the area indicating the display state of the image indicates the luminance when the maximum display luminance capacity is 100%. For example, B1 surrounded by a dotted line indicates the luminance of 40%.

With such an image display method, it is possible to improve the quality of moving images when the gradation level of an input image signal is smaller than a certain level while ensuring the same maximum brightness and contrast as in the past.

Similarly to Patent Document 1, in Patent Document 2, a plurality of subframe periods are provided in a frame period in order to suppress a decrease in luminance in a black-insertion-type image display device, and subsequent subframe periods A method of attenuating the brightness of the image at a predetermined rate according to the brightness value of the input image signal is disclosed. As a result, the luminance value of the subsequent subframe is attenuated at a predetermined rate with respect to the luminance value of the preceding subframe, so that blurring due to the flow of a visual moving image in a general hold type display device is prevented. Can be prevented. Further, in the subsequent subframe period, it is attenuated at a predetermined rate according to the luminance value of the input image signal, and is displayed with a luminance value other than 0%. Therefore, the general black shown in FIG. 50 and FIG. It is possible to suppress a decrease in luminance as compared with an insertion type image display device.
JP 2001-296841 A JP 2002-23707 A

  In the conventional image display device disclosed in Patent Document 1 described above, when displaying an image in which an object moves horizontally on a stationary background, when the gradation level of the input image signal is sufficiently small, The same effects as those of the black insertion method shown in FIGS. 50 and 51 can be obtained. However, this image display apparatus has the following problems when the gradation level of the input image signal is large.

  FIG. 53 is a diagram showing how the brightness distribution looks for an observer who is gazing at a moving object when the video as shown in FIG. 52 is displayed.

  As shown in FIG. 53, there are places that are too bright or too dark than the original image. As a result, abnormal light and darkness that cannot be seen when the object is stationary can be seen at the front end and rear end of the moving object, and this deteriorates the quality of the moving image.

  The reason why such abnormal light and darkness occurs is that, in the image display period of one frame, the temporal barycentric position of the period during which the pixels are turned on is when the gradation level of the input image signal is less than 50%. This is because the gradation level of the input image signal is greatly different from the case where the gradation level is 50% or more. For example, when the gradation level of the input image signal is less than 50%, the temporal center-of-gravity position of the display luminance during the pixel lighting period has a gradation level of 0% in the second subframe period T202. Since the image signal is supplied, the first subframe period T201 is entered. On the other hand, when the gradation level of the input image signal is 50% or more, the temporal gravity center position of the pixel lighting period (display luminance) is the gradation level at which the second subframe period T202 is 100%. Since the second image signal is supplied, the second half subframe period T202 occurs. As a result, in the time integration of the luminance change in the trajectory direction in which the object has moved, there are places that are too bright or too dark than the original image at the front and rear ends of the moving object.

  On the other hand, most of the current general image signals such as TV broadcast, video playback signal output and PC (personal computer) image output are generated assuming the gamma luminance characteristics of CRT (cathode ray tube). Has been output. A display panel using a hold-type display element such as a liquid crystal display element or an EL display element also has the same gamma luminance characteristic as that of a CRT in order to maintain the compatibility of gradation expression for these general image signals. It is common to do.

As shown in FIG. 54, the relationship between the input gradation of the display panel having such a gamma luminance characteristic and the display luminance is a curve that is recessed toward the lower overall luminance. Therefore, it can be seen that, for example, a point with a luminance of 50% and a point with a gradation level of 50% do not match.

  Using such a hold-type display element, display control as shown in the seventh embodiment of Patent Document 1 was performed using a general display panel having a gamma luminance characteristic similar to that of a CRT. FIG. 55 shows the relationship between the gradation level of the input signal and the luminance time integral value corresponding to the brightness perceived by the observer.

  In the seventh embodiment of Patent Document 1, an image signal is supplied in two subframe periods (a first half subframe period and a second half subframe period) with a gradation level of 50% as a boundary, or one subframe period. Whether to supply the image signal only in the (first half subframe period) is switched. For this reason, the luminance characteristic has two dents at the point where the gradation level is 50%, and color reproducibility suitable for general image signal input cannot be realized.

  Further, in Patent Document 2, since the display is turned on also in the subsequent subframe period, it is possible to suppress a decrease in luminance and contrast as compared with the general black insertion type image display device shown in FIGS. 50 and 51. However, the effect of improving motion blur is weak. Further, sufficient contrast cannot be ensured as compared with a general hold type display device.

  The present invention solves the above-described conventional problems. In an image display apparatus using a hold-type display element, the temporal center of gravity of display luminance is controlled according to the gradation level of an input image signal while suppressing a decrease in maximum luminance and contrast. Gradation expression for image signal input created on the premise of output to an image display device that minimizes image quality degradation caused by different positions and has general luminance characteristics (eg, gamma luminance characteristics) Image display device capable of improving degradation of moving image quality, which is called afterimage or motion blur, while maintaining compatibility, electronic equipment using the display portion, liquid crystal television device, liquid crystal monitor device, image display method, and A display control program for causing a computer to execute and a computer-readable readable recording medium on which the display control program is recorded .

The image display device according to the present invention divides one frame period into a plurality of subframe periods including a first subframe, a second subframe,..., An nth (n is an integer of 2 or more) subframe , In an image display apparatus that determines the gradation level of each subframe in accordance with the gradation level of an input image signal and supplies the image to the image display unit to display an image, the temporal center of the one-frame period or the temporal center Display control means for supplying a large gradation level in order from the nearest subframe , the display control means, the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in the one frame period, In order to show an appropriate gamma luminance characteristic, the gradation level of the image signal that is increased or decreased according to the input image signal and is supplied in each subframe period is set. It is achieved. The image display apparatus of the present invention minimizes the gradation level of all subframes when the gradation level of the input image signal is minimum, and all subframes when the gradation level of the input image signal is maximum. When the gradation level of the frame is the maximum and the gradation level of the input image signal is other than the minimum and the maximum, the one frame period is composed of three or more subframes. In the case of being composed of two subframes while distributing a large gradation level in order from the temporal center of or near to the temporal center, distributing a large gradation level in order from one subframe, An integrated value of display luminance in one frame period corresponding to the input image signal is subjected to arithmetic processing or conversion processing using a table so as to reproduce a predetermined gradation luminance characteristic. In to confirm the gradation level output are those having a display control means for displaying an image on the image display unit, the object can be achieved.

The image display device according to the present invention displays an image on the image display unit during n subframe periods including a first subframe, a second subframe,..., An nth (n is an integer of 2 or more) subframe. An image display device that displays an image for one frame period by a total amount of time integration of luminance, and performs display control for performing image display control of n subframe periods for the image display unit for each frame period Control means, and the display control means so that the relationship between the gradation level of the inputted image signal and the time integration amount of the display brightness in the one frame period shows an appropriate gamma brightness characteristic. when it is increased or decreased in accordance with the image signal to set the tone level of the image signal supplied to each sub-frame periods closest subfolder to the temporal center or said center of one frame period in which the image display is performed In the image period, the image having the maximum gradation level in a range in which the total amount of time integration of the luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal When a signal is supplied to the image display unit, and the total amount of time integration of luminance displayed in the center or the subframe period closest to the center does not reach the luminance corresponding to the gradation level of the input image signal In the sub-frame period before and after the center or the sub-frame period closest to the center, the total amount of time integration of luminance displayed in the n sub-frame periods is the gradation of the input image signal. An image signal having the maximum gradation level within a range not exceeding the luminance level corresponding to the level is supplied to the image display unit, and the center or the subframe period closest to the center and the subframes before and after the subframe period In the case where the total amount of time integration of the luminance displayed during the period does not reach the luminance corresponding to the gradation level of the input image signal, the n subframe periods are further included in the preceding and succeeding subframe periods. A control for supplying the image display unit with an image signal having the maximum gradation level within a range in which the total amount of time integration of the displayed luminance does not exceed the luminance level corresponding to the gradation level of the input image signal; The total amount of time integration of luminance corresponding to the gradation levels of all the supplied image signals is repeated until the luminance corresponding to the gradation level of the input image signal reaches the luminance level. The image signal having the gradation level smaller than or smaller than the predetermined value is supplied to the image display unit.

The image display apparatus according to the present invention is an image display apparatus that displays an image for one frame period based on the total amount of time integration of luminance displayed on the image display unit in n (n is an odd number of 3 or more) subframe periods. The image display unit includes display control means for performing image display control of n subframe periods for each frame period, and the display control means is arranged in order from the earliest in time, Or, in order from the slowest, the first subframe, the second subframe,..., The nth subframe period consisting of the nth subframe, becomes the temporal center of one frame period during which image display is performed. The m-th subframe period is set by m = (n + 1) / 2, and T1, T2,... T [ (N + 1) / 2] When set, if the gradation level of the input image signal is equal to or less than the threshold T1, the gradation that is increased or decreased according to the gradation level of the input image signal in the m-th subframe period An image signal of a level is supplied to the image display unit, and an image signal of a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit in the other subframe period. Is larger than the threshold value T1 and equal to or smaller than the threshold value T2, an image signal having a gradation level that is maximum or larger than a predetermined value is supplied to the image display unit in the m-th subframe period, In the frame period and the (m + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the other subframes are supplied. In the period, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit, and when the gradation level of the input image signal is larger than the threshold value T2 and equal to or less than the threshold value T3, In the m-th subframe period, the m-1st subframe period, and the m + 1th subframe period, an image signal having a maximum gradation level or greater than a predetermined value is supplied to the image display unit, and the m-2th subframe period In the (m + 2) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. An image signal having a small gradation level is supplied to the image display unit, and thereafter, the gradation level of the input image signal is larger than a threshold value Tx-1 (x is an integer of 4 or more). And when the value is equal to or less than the threshold value Tx, the maximum value or a predetermined value in each subframe period from the [m− (x−2)] subframe period to the [m + (x−2)] subframe period. An image signal having a large gradation level is supplied to the image display unit, and the input image signal is input in the [m− (x−1)] subframe period and the [m + (x−1)] subframe period. An image signal of a gradation level that is increased or decreased according to the gradation level is supplied to the image display unit, and an image signal of a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit in other subframe periods. Therefore, the length of the m-th subframe period is set to be longer than the lengths of the other subframe periods , thereby achieving the above object.

The image display device of the present invention is an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in n (n is an even number of 2 or more) subframe periods. The image display unit includes display control means for performing image display control of n subframe periods for each frame period, and the display control means is arranged in order from the earliest in time, Or, in order from the slowest, the first subframe, the second subframe,..., The n-th subframe period consisting of the nth subframe is the most centered in the temporal center of one frame period in which image display is performed. Two near m1 subframe periods and m2 subframe periods are set by m1 = n / 2 and m2 = n / 2 + 1, and n / 2 thresholds are smaller in value than the gradation level of the image signal. When T1, T2,..., T [n / 2] are set in order, the m1-th subframe period when the gradation level of the input image signal is equal to or lower than the threshold T1 In the m2nd subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the minimum or predetermined value is supplied in the other subframe period. An image signal having a smaller gradation level is supplied to the image display unit. When the gradation level of the input image signal is larger than the threshold value T1 and equal to or smaller than the threshold value T2, the m1st subframe period and An image signal having a gradation level that is maximum or greater than a predetermined value in the m2nd subframe period is supplied to the image display unit, and in the m1-1 subframe period and the m2 + 1 subframe period. An image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and an image having a gradation level that is minimum or smaller than a predetermined value in other subframe periods. A signal is supplied to the image display unit, and when the gradation level of the input image signal is greater than the threshold T2 and equal to or less than the threshold T3, the m1 subframe period, the m2 subframe period, In the m1-1 subframe period and the m2 + 1 subframe period, an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit, and in the m1-2 subframe period and the m2 + 2 subframe period. An image signal having a gradation level that is increased or decreased in accordance with the gradation level of the input image signal is supplied to the image display unit, and the image signal is transmitted during other subframe periods. Supplies an image signal having a minimum or smaller gradation level to the image display unit, and thereafter the gradation level of the input image signal is larger than a threshold Tx-1 (x is an integer of 4 or more), When the threshold value is less than or equal to the threshold Tx, the maximum or greater than a predetermined value in each subframe period from the [m1- (x-2)] subframe period to the [m2 + (x-2)] subframe period. The tone level image signal is supplied to the image display unit, and the gray level of the input image signal in the [m1- (x-1)] subframe period and the [m2 + (x-1)] subframe period the gradation level image signal to be increased or decreased depending on the level and supplies to the image display unit, stuff supplies an image signal of the minimum or predetermined value smaller than the gradation levels to the image display unit in the other sub frame period And , The combined length of said m1 subframe period and said m2 sub frame period Ri longer set der than the length of the other sub-frame period, the object is achieved.

An image display device according to the present invention is an image display device in which an image display of one frame period is performed by a total amount of time integration of luminance displayed on an image display unit in two subframe periods. A display control means for performing image display control of the two subframe periods on the image display unit for each frame period, the subframe α period and the other subframe as a subframe β period; The control means increases or decreases in accordance with the gradation level of the input image signal in the subframe α period when the gradation level of the input image signal is equal to or less than a uniquely determined threshold value. An image signal having a gradation level is supplied to the image display unit, and an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit during the subframe β period. When the gradation level of the image signal is larger than the threshold value, the image signal having the gradation level that is maximum or larger than the predetermined value is supplied to the image display unit in the subframe α period, and in the subframe β period, An image signal having a gradation level that is increased or decreased according to an input image signal is supplied to the image display unit. In the image display unit, the response time when the display brightness increases is compared with the response time. When the response time when the display luminance decreases is short, the subframe α period is set as the second subframe of the one frame period, and when this is long, the subframe α period is set as the one frame period. In the first half of the subframe , the above object is achieved.

The image display device of the present invention is an image display device in which image display for one frame period is performed by the total amount of time integration of luminance displayed on the image display unit in two subframe periods,
Display control means for performing image display control of the two subframe periods for the image display unit for each frame period, one subframe period being a subframe α period, and the other subframe being a subframe β Two gradation level threshold values T1 and T2 are defined, and the threshold value T2 is larger than the threshold value T1, and the display control means has the gradation level of the input image signal equal to or less than the threshold value T1. In this case, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit in the subframe α period, and the minimum or predetermined value is supplied in the subframe β period. When an image signal having a smaller gradation level is supplied to the image display unit and the gradation level of the input image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the subframe α period. The image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in the subframe β period, the gradation level supplied in the subframe α period An image signal having a smaller level and a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the gradation level of the input image signal is greater than the threshold T2. In this case, an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit in the subframe α period, and the gradation that is increased or decreased according to the input image signal in the subframe β period. It is intended to supply a level image signal to the image display unit, in the image display unit, compared to the response time in the case where the display luminance increases, the response time when the display luminance is lowered is short Expediently, the subframe α period as the second half of the sub-frames in the one frame period, if this is long, and the sub-frame α period as the first half of the sub-frames in the one frame period This achieves the above object.

  The image display apparatus of the present invention is an image display apparatus that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods, and for each frame period. Display control means for performing image display control of the two subframe periods for the image display unit, wherein one subframe period is a subframe α period, the other subframe is a subframe β period, and 2 Two gradation level threshold values T1 and T2 are defined, T2 is a value larger than T1, gradation level L is uniquely defined, and the display control means is configured to calculate the level of the input image signal. When the tone level is equal to or lower than the threshold value T1, during the subframe α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and In the frame β period, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit, and when the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, In the sub-frame α period, the gradation level L is supplied, and in the sub-frame β period, the gradation display level image signal that is increased or decreased according to the input image signal is supplied to the image display unit and input. When the gradation level of the image signal is larger than the threshold value T2, during the subframe α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. In the subframe β period, an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit, thereby achieving the above object.

An image display device according to the present invention is an image display device in which an image display of one frame period is performed by a total amount of time integration of luminance displayed on an image display unit in two subframe periods. A display control means for performing image display control of the two subframe periods on the image display unit for each frame period, the subframe α period and the other subframe as a subframe β period; The control means estimates and generates a temporally intermediate frame image for two consecutively input images, and the gradation level of the input image signal is determined during the subframe α period. When the threshold value is not more than a uniquely determined threshold value, an image signal having a gradation level that is increased or decreased in accordance with the gradation level of the input image signal is supplied to the image display unit, and the input image is displayed. When the gradation level of the signal is larger than the threshold value, the image signal of the gradation level that is maximum or larger than the predetermined value is supplied to the image display unit, and the image in the intermediate state frame image in the subframe β period When the gradation level of the signal is equal to or lower than the threshold, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit, and the gradation level in the intermediate frame image is lower than the threshold. If larger, an image signal having a gradation level that is increased or decreased according to the gradation level of the image signal in the intermediate frame image is supplied to the image display unit. When the response time when the display luminance decreases is shorter than the response time when the luminance increases, the subframe α period is changed to the subframe in the latter half of the one frame period. If this is long, the sub-frame α period is the first half of the one-frame period , thereby achieving the above object.

  An image display device according to the present invention is an image display device in which an image display of one frame period is performed by a total amount of time integration of luminance displayed on an image display unit in two subframe periods. A display control means for performing image display control of the two subframe periods on the image display unit for each frame period, the subframe α period and the other subframe as a subframe β period; The control means increases or decreases according to the gradation level of the input image signal when the gradation level of the input image signal is equal to or less than a uniquely determined threshold value during the subframe α period. An image signal having a gradation level is supplied to the image display unit, and when the gradation level of the input image signal is greater than the threshold value, an image signal having a gradation level greater than the maximum or predetermined value is selected. An average value of the gradation level of the input image signal supplied to the image display unit and the gradation level of the image signal input to the immediately preceding or succeeding one frame in the subframe β period Is equal to or smaller than the threshold value, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit. If the average value is larger than the threshold value, the image signal is The image signal of the gradation level to be increased / decreased is supplied to the image display unit, whereby the above object is achieved.

  Preferably, the period lengths of the subframes in the image display device of the present invention are the same or different from each other.

Further preferably, in the image display apparatus of the present invention, the time center of one frame period or the length of a subframe period of a subframe close to the time center is longer than the length of another subframe period. Is set to

  Further preferably, in the image display device of the present invention, when the gradation level of the input image signal is larger than the threshold value T1 and equal to or less than the threshold value T2, the gradation level supplied in the subframe α period; The gradation level supplied in the frame β period is such that the difference between the gradation level in the subframe α period and the gradation level in the subframe β period is a constant value, or the luminance in the subframe α period. The difference between the level and the luminance level in the subframe β period is set to a constant value.

  Further preferably, in the image display device of the present invention, when the gradation level of the input image signal is larger than a threshold value T1 and equal to or less than the threshold value T2, the gradation level supplied in the subframe α period; The gradation level supplied in the subframe β period is that the relationship between the gradation level in the subframe α period and the gradation level in the subframe β period is set by one function, or the subframe α It is determined that the relationship between the luminance level of the period and the luminance level of the subframe β period is set by one function.

  Further preferably, in the image display unit of the image display device according to the present invention, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α The period is the latter half of the one frame period, and if this is long, the subframe α period is the first half of the one frame period.

Further preferably, in the image display unit of the image display device of the present invention, the maximum display luminance level is Lmax and the minimum display luminance level is Lmin, and the state is switched from the display luminance level Lmin state to the display luminance level Lmax state. If the response time when switching from the display luminance level Lmax state to the display luminance level Lmin state is shorter than the response time in the case, the subframe α period is set to the second half of the one frame period. If the frame is long, the subframe α period is the first half of the one frame period.

  Preferably, the display control means in the image display apparatus of the present invention sets an upper limit value for the gradation level of the image signal supplied in each subframe period.

Further preferably, the display control means in the image display device according to the present invention is configured such that the upper limit for the gradation level of the image signal supplied in the first subframe period, the second subframe period,..., The nth subframe period. The values are L1, L2,..., Ln, and among the n subframe periods, the temporal center of one frame period in which image display is performed or the subframe period closest to the center is the jth subframe period. And i is an integer between 0 and j,
L [j−i] ≧ L [j− (i + 1)],
L [j + i] ≧ L [j + (i + 1)],
In order to satisfy this relationship, an upper limit value is set for the image signal of the gradation level supplied in each subframe period.

  Further preferably, the display control means in the image display device of the present invention is configured such that the upper limit value L1 for the gradation level of the image signal supplied during the subframe α period ≧ the gradation level of the image signal supplied during the subframe β period. The upper limit value for the image signal of the gradation level is set for each subframe period so as to satisfy the relationship of the upper limit value L2.

  Further preferably, the display control means in the image display device of the present invention is such that the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period exhibits an appropriate gamma luminance characteristic. As described above, the gradation level of the image signal that is increased or decreased according to the input image signal and is supplied in each subframe period is set.

  Further preferably, the display control means in the image display device of the present invention is such that the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period exhibits an appropriate gamma luminance characteristic. As described above, a threshold value that is a criterion for determining the gradation level of the image signal in each subframe period and a gradation level of the image signal that is increased or decreased according to the input image signal and supplied in each subframe period are set. To do.

  Further preferably, the image display device of the present invention further includes a temperature detection means for detecting the panel temperature or its surrounding temperature, and the display control means is inputted in accordance with the temperature detected by the temperature detection means. The gradation level of the image signal that is increased or decreased according to the image signal and is supplied in each subframe period is set.

  Further preferably, in the image display device of the present invention, the image display device further includes a temperature detection means for detecting a panel temperature or its surrounding temperature, and the display control means is configured to display each sub-unit according to the temperature detected by the temperature detection means. A threshold value that is a criterion for determining the gradation level of the image signal in the frame period and a gradation level of the image signal that is increased or decreased according to the input image signal and supplied in each subframe period are set.

  Further preferably, in the image display device of the present invention, when the input image signal is composed of image signals of a plurality of color components, the display control means is configured to provide a gradation level of the input image signal. The ratio between the luminances displayed for each sub-frame period for the color components other than the color component having the largest value is determined for each sub-frame period for the color component having the highest gradation level of the input image signal. The gradation level of the image signal supplied in each subframe period is set so as to be the same as the ratio between the displayed luminances.

  Further preferably, the display control means in the image display device of the present invention comprises a timing control means, a line data storage means for temporarily receiving an image signal for one horizontal line, and the timing control means. Frame storage data selection means for controlling whether to transfer data from the line data storage means to the frame data storage means or to output data one frame before read from the frame data storage means, and the line A first gradation for converting the gradation level of the image signal supplied from the data storage means into a gradation level that is increased or decreased in accordance with the gradation level that is maximum or larger than a predetermined value or the gradation level of the input image signal. The gradation level of the image signal supplied from the conversion means and the frame storage data selection means Second gradation conversion means for converting to a gradation level smaller than the value or a gradation level that is increased or decreased according to the gradation level of the input image signal, and the first gradation controlled by the timing control means. Output data selection means for switching the image signal output from the conversion means and the image signal output from the second gradation conversion means to be supplied to the image display unit is provided.

  Further preferably, the display control means in the image display device of the present invention is a timing control means, a line data storage means for temporarily receiving an image signal for one horizontal line, and a plurality of horizontal lines. Data is transferred from the line data storage means to the frame data storage means under the control of the first multiple line data storage means and the second multiple line data storage means for temporarily holding the image signal and the timing control means. Alternatively, the image data of one frame before read from the frame data storage means is transferred to the first plurality of line data storage means, and the image data of two frames before read from the frame data storage means is transferred to the second Frame storage data selection means for switching to transfer to a plurality of line data storage means, the first Intermediate image generation means for estimating and generating frame image data in an intermediate state with respect to two frames of image data supplied from the several line data storage means and the second multiple line data storage means, and the timing control A temporary storage data selection means for switching and outputting the image data supplied from the first multiple line data storage means and the image data supplied from the second multiple line data storage means, controlled by the means; The first floor that converts the gradation level of the image signal supplied from the stored data selection means to a gradation level that is increased or decreased according to the maximum or larger gradation level or the gradation level of the input image signal. The tone level of the image signal supplied from the tone conversion unit and the intermediate image generation unit is set to a minimum or smaller tone level than the predetermined level. Second gradation conversion means for converting to a gradation level that is increased or decreased according to the gradation level of the input image signal, and an image output from the first gradation conversion means under the control of the timing control means And an output data selection unit that switches the image signal output from the second gradation conversion unit and supplies the image signal to the image display unit.

Further preferably, the display control means in the image display device of the present invention comprises a timing control means, a line data storage means for temporarily receiving an image signal for one horizontal line, and a plurality of horizontal lines. The first multi-line data storage means and the second multi-line data storage means for temporarily holding the image signal of the image data, and the timing control means control the image data from the line data storage means to the frame data storage means. The image data of one frame before read from the frame data storage means is transferred to the first multi-line data storage means, and the image data of two frames before read from the frame data storage means is transferred to the first multi-line data storage means. 2 frame storage data selection means for switching to transfer to a plurality of line data storage means, A gradation level averaging means for calculating an average value of gradation levels of two image signals supplied from the plurality of line data storage means and the second plurality of line data storage means and supplying the average value to the second gradation conversion means; Temporary storage data selection means for switching and outputting image data supplied from the first plurality of line data storage means or image data supplied from the second plurality of line data storage means, controlled by the timing control means And converting the gradation level of the image signal supplied from the temporarily stored data selection means to a gradation level that is increased or decreased in accordance with the maximum or larger gradation level or the gradation level of the input image signal. The gradation level of the image signal supplied from the first gradation conversion means and the gradation level averaging means is a minimum or smaller gradation level than a predetermined value or Second gradation conversion means for converting to a gradation level that is increased or decreased according to the gradation level of the input image signal, and an image signal that is output from the first gradation conversion means, controlled by the timing control means Or an output data selection unit that switches the image signal output from the second gradation conversion unit and supplies the image signal to the image display unit.

  Further preferably, in the image display device of the present invention, when n is 3, the display control means is a line for temporarily holding a timing control means and an image signal for one horizontal line as input. Controlled by the data storage means and the timing control means, the data is transferred from the line data storage means to the frame data storage means, or the data before 1/4 frame read from the frame data storage means is output. Frame storage data selection means for switching to output data of 3/4 frame before, and data supplied from the line data storage means or supplied from the frame storage data selection means, controlled by the timing control means Gradation conversion source selection means for switching and outputting data before 3/4 frame The gradation level of the image signal supplied from the frame storage data selection means is converted into a gradation level that is increased or decreased in accordance with the maximum or larger gradation level or the gradation level of the input image signal. The gradation level of the image signal supplied from the first gradation conversion means and the gradation conversion source selection means is increased or decreased according to the gradation level that is minimum or smaller than a predetermined value or the gradation level of the input image signal. Second gradation conversion means for converting to the gradation level to be output, and an image signal output from the first gradation conversion means or output from the second gradation conversion means under the control of the timing control means. Output data selection means for switching the image signal and supplying it to the image display unit.

  Further preferably, the gradation level larger than the predetermined value in the image display device of the present invention is a gradation level larger than 90% when the maximum is 100%, and the gradation level smaller than the predetermined value is the minimum The gradation level is smaller than 10 percent when the value is 0 percent.

  Preferably, the gradation level larger than the predetermined value in the image display device of the present invention is a gradation level corresponding to a luminance level larger than 90 percent when the maximum luminance level is set to 100 percent. The small gradation level is a gradation level corresponding to a luminance level smaller than 10 percent when the minimum luminance level is 0 percent.

  Preferably, the gradation level larger than the predetermined value in the image display device of the present invention is a gradation level larger than 98% when the maximum is 100%, and the gradation level smaller than the predetermined value is the minimum The gradation level is smaller than 2 percent when 0 is set to 0 percent.

  Preferably, the gradation level larger than the predetermined value in the image display device of the present invention is a gradation level corresponding to a luminance level larger than 98% when the maximum luminance level is set to 100%. The small gradation level is a gradation level corresponding to a luminance level smaller than 2 percent when the minimum luminance level is 0 percent.

  Preferably, the image display device of the present invention further includes a gamma luminance characteristic setting unit that allows the gamma luminance characteristic to be set from outside, and the display control unit is set from the outside by the gamma luminance characteristic setting unit. It is possible to change to a gamma luminance characteristic that has been set.

Preferably, in the image display device of the present invention, when the plurality of subframe periods are three or more subframe periods, the gradation level sequentially allocated is higher in the center portion than in the end portion in the one frame period. It has become.

  Preferably, when the plurality of subframe periods in the image display device of the present invention are three or more subframe periods, the luminance levels of the sequentially assigned subframe images are the one frame period and the central portion thereof is It is higher than the edge.

  Preferably, the change in the center of gravity of the time integral of the luminance displayed in the plurality of subframe periods in the image display device of the present invention is within one subframe period.

  Preferably, the display control means in the image display device of the present invention controls display for each of the pixel portions on the display screen.

  Preferably, the pixel portion in the image display device of the present invention is one pixel or a predetermined number of pixels.

  The electronic apparatus of the present invention performs image display on the display screen of the display unit using the image display device, and thereby the above object is achieved.

  The liquid crystal television device of the present invention includes the image display device, and a tuner that enables the display control means of the image display device to output a television broadcast signal with a selected channel. Achieved.

  The liquid crystal monitor device of the present invention includes the image display device, and a signal processing unit capable of outputting a monitor image signal obtained by signal-processing an external monitor signal to the display control means of the image display device, and This achieves the above object.

The image display method of the present invention uses an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in n (n is an integer of 2 or more) subframe periods. In the display method, the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in the one-frame period shows an appropriate gamma luminance characteristic. In accordance with this, the gradation level of the image signal that is increased / decreased and supplied in each sub-frame period is set . The image signal having the maximum gradation level within a range in which the total amount of time integration of the luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal. And the total amount of time integration of luminance displayed in the center or the subframe period closest to the center does not reach the luminance corresponding to the gradation level of the input image signal. In this case, in the subframe period before and after the center or the subframe period closest to the center, the total amount of time integration of luminance displayed in the n subframe periods is the gradation level of the input image signal. A process of supplying an image signal of the maximum gradation level to the image display unit within a range not exceeding the luminance level corresponding to, and the center or the subframe period closest to the center and the subframe periods before and after the center. When the total amount of time integration of the luminance does not reach the luminance corresponding to the gradation level of the input image signal, the n sub-frames are further sub-frame periods before and after that. The image signal having the maximum gradation level is supplied to the image display unit in a range where the total amount of time integration of the luminance displayed in the frame period does not exceed the luminance level corresponding to the gradation level of the input image signal. The control is repeated until the total amount of time integration of luminance corresponding to the gradation levels of all supplied image signals reaches the luminance corresponding to the gradation levels of the input image signals. And a process of supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the image display unit in the subframe period, thereby achieving the above object.

The image display method of the present invention uses an image display device that displays an image for one frame period based on the total amount of time integration of luminance displayed on the image display unit in n (n is an odd number of 3 or more) subframe periods. An image display method, in which n subframe periods are composed of a first subframe, a second subframe,..., An nth subframe, in order from the earliest in time or from the latest. The m-th subframe period, which is the temporal center of one frame period in which image display is performed, is set by m = (n + 1) / 2, and (n + 1) / 2 pieces of image signal gradation levels are set. The threshold is set to T1, T2,..., T [(n + 1) / 2] in ascending order, and the length of the m-th subframe period is the length of another subframe period. To be longer than If it is set, when the gradation level of the input image signal is the threshold value T1 or less, in said m sub-frame periods, the gradation level which is increased or decreased in accordance with the gradation level of the input image signal The image signal is supplied to the image display unit, and in the other sub-frame period, the image signal having the minimum or smaller gradation level than the predetermined value is supplied to the image display unit, and the gradation of the input image signal When the level is greater than the threshold value T1 and less than or equal to the threshold value T2, an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit in the m-th subframe period. In the subframe period and the (m + 1) th subframe period, an image signal with a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and Processing for supplying an image signal with a gradation level that is minimum or smaller than a predetermined value to the image display unit in the frame period, and the gradation level of the input image signal is greater than the threshold value T2 and less than or equal to the threshold value T3 In the m-th subframe period, the (m-1) th subframe period, and the (m + 1) th subframe period, an image signal having a gradation level that is maximum or larger than a predetermined value is supplied to the image display unit, and the (m-2) th subframe period is supplied. In the frame period and the (m + 2) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. A process of supplying an image signal having a gradation level smaller than the value to the image display unit, and thereafter, the gradation level of the input image signal is a threshold Tx−1 (x is 4 or less). In each subframe period from the [m− (x−2)] th subframe period to the [m + (x−2)] th subframe period when it is larger than the above integer) and below the threshold Tx An image signal having a maximum gradation level or a gradation level larger than a predetermined value is supplied to the image display unit, and input in the [m− (x−1)] subframe period and the [m + (x−1)] subframe period. An image signal with a gradation level that is increased or decreased according to the gradation level of the image signal to be generated is supplied to the image display unit, and an image signal with a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit during the other subframe periods. Processing to be supplied to the image display unit, whereby the above object is achieved.

The image display method of the present invention uses an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in n (n is an even number of 2 or more) subframe periods. An image display method, in which n subframe periods are composed of a first subframe, a second subframe,..., An nth subframe, in order from the earliest in time or from the latest. Two m1 subframe periods and m2 subframe periods that are closest to the temporal center of one frame period in which image display is performed are set by m1 = n / 2 and m2 = n / 2 + 1, and the level of the image signal is set. relative gray level, T1 from those n / 2 pieces of threshold smaller value in order, T2, ···, in a case that has been set as T [n / 2], said m1 sub frame period and the If the combined length of the m2 subframe period is longer than the length of the other sub-frame period, when the gradation level of the input image signal is the threshold value T1 or less, said m1 sub frame period and the In the m2nd subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in other subframe periods, the minimum or predetermined value is exceeded. A process of supplying an image signal of a small gradation level to the image display unit, and when the gradation level of the input image signal is larger than the threshold value T1 and equal to or smaller than the threshold value T2, the m1st subframe period and An image signal having a maximum gradation level or greater than a predetermined value is supplied to the image display unit in the m2 subframe period, and the m1-1 subframe period and the m2 + 1 subframe are supplied. In the frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in other subframe periods, the gradation level is minimum or smaller than a predetermined value. When the gradation level of the input image signal is larger than the threshold value T2 and equal to or less than the threshold value T3, the m1st subframe period and the m2nd subframe period In the frame period, the m1-1 subframe period, and the m2 + 1 subframe period, an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit, and the m1-2 subframe period and the m2 + 2 subframe are supplied. In the frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the other signals are supplied. In the frame period, a process of supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the image display unit, and thereafter, the gradation level of the input image signal is a threshold value Tx−1 (x is 4 or more). Greater than an integer) and less than or equal to the threshold Tx, the maximum or each subframe period from the [m1- (x-2)] subframe period to the [m2 + (x-2)] subframe period or An image signal having a gradation level larger than a predetermined value is supplied to the image display unit, and is input in the [m1- (x-1)] subframe period and the [m2 + (x-1)] subframe period. An image signal having a gradation level that is increased or decreased according to the gradation level of the image signal is supplied to the image display unit, and an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit in other subframe periods. And a process for supplying to the display unit, the object can be achieved.

An image display method according to the present invention is an image display method using an image display device that displays an image for one frame period based on a total amount of time integration of luminance displayed on an image display unit in two subframe periods. When the subframe period is the subframe α period, the other subframe is the subframe β period, and the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value, in the subframe α period, An image signal having a gradation level that is increased or decreased in accordance with the gradation level of the input image signal is supplied to the image display unit, and an image signal having a gradation level that is minimum or smaller than a predetermined value in the subframe β period. When the gradation level of the processing to be supplied to the image display unit and the input image signal is larger than the threshold value, the maximum or larger than the predetermined value in the subframe α period Processing to supply an image signal of a large gradation level to the image display unit, and to supply an image signal of a gradation level increased or decreased according to the input image signal in the subframe β period to the image display unit. In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is set to the one frame. If the subframe is the latter half of the period and this is longer, the subframe α period is the first half of the one frame period , thereby achieving the above-mentioned object.

An image display method according to the present invention is an image display method using an image display device that displays an image for one frame period based on a total amount of time integration of luminance displayed on an image display unit in two subframe periods. The subframe period is the subframe α period, and the other subframe is the subframe β period. Two gradation level threshold values T1 and T2 are determined. The threshold value T2 is larger than the threshold value T1 and is input. When the gradation level of the image signal is equal to or less than the threshold value T1, in the subframe α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. In the subframe β period, a process of supplying an image signal having a gradation level smaller than or smaller than a predetermined value to the image display unit, and the gradation level of the input image signal is equal to the threshold T1 When it is large and is equal to or less than the threshold T2, in the subframe α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in the subframe β period Is a level smaller than the gradation level supplied in the sub-frame α period, and a process of supplying an image signal of a gradation level that is increased or decreased according to the gradation level of the input image signal to the image display unit. When the gradation level of the input image signal is larger than the threshold value T2, the image signal having the maximum gradation level or larger than the predetermined value is supplied to the image display unit in the subframe α period, and in the subframe β period. upper gray levels image signal to be increased or decreased in accordance with an image signal is input are those having a process for supplying to the image display unit, in the image display unit, the display brightness When the response time when the display brightness decreases is shorter than the response time when the display luminance is reduced, the subframe α period is set as the second subframe of the one frame period. The subframe α period is the first half of the one frame period , thereby achieving the above object.

The image display method of the present invention is an image display method using an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods, The frame period is a subframe α period, the other subframe is a subframe β period, and two gradation level thresholds T1 and T2 are determined. T2 is a value larger than T1, and the gradation level L is The gradation level that is uniquely determined and is increased or decreased in accordance with the gradation level of the input image signal in the subframe α period when the gradation level of the input image signal is equal to or lower than the threshold T1. And a process of supplying an image signal having a gradation level smaller than a minimum or a predetermined value to the image display unit during the subframe β period, When the gradation level of the image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the gradation level L is supplied during the subframe α period, and the gradation level is increased or decreased according to the input image signal during the subframe β period. Processing for supplying an image signal of a gradation level to the image display unit, and when the gradation level of the input image signal is greater than a threshold value T2, in the subframe α period, the level of the input image signal An image signal having a gradation level that is increased or decreased in accordance with the tone level is supplied to the image display unit, and an image signal having a gradation level that is maximum or greater than a predetermined value is supplied to the image display unit in the subframe β period. And the above object is achieved thereby.

An image display method according to the present invention is an image display method using an image display device that displays an image for one frame period based on a total amount of time integration of luminance displayed on an image display unit in two subframe periods. A process in which a subframe period is a subframe α period and the other subframe is a subframe β period, and a frame image in an intermediate state is estimated and generated with respect to two consecutively input images. The gradation level that is increased or decreased according to the gradation level of the input image signal when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value in the subframe α period When the gradation level of the input image signal is greater than the threshold value, the image signal having the gradation level that is the maximum or greater than the predetermined value is supplied to the image display unit. When the gradation level of the image signal in the intermediate frame image is equal to or lower than the threshold value during the subframe β period, an image signal having a minimum gradation level or smaller than a predetermined value is output to the image. A gradation level that is supplied to the display unit and is increased or decreased according to the gradation level of the image signal in the image in the intermediate state when the gradation level in the image in the intermediate state is greater than the threshold value. And a process of supplying an image signal to the image display unit. In the image display unit, the response time when the display luminance decreases is shorter than the response time when the display luminance increases. In this case, the subframe α period is set to the second half subframe in the one frame period, and when this is long, the subframe α period is set to the first subframe in the one frame period. And frame, the objects can be achieved.

  The image display method of the present invention is an image display method using an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods, When the frame period is a subframe α period and the other subframe is a subframe β period, and the gradation level of the input image signal is equal to or lower than a uniquely determined threshold in the subframe α period, An image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the maximum or predetermined value is obtained when the gradation level of the input image signal is greater than the threshold value. A process of supplying an image signal having a gradation level greater than the value to the image display unit, and the gradation level of the input image signal in the subframe β period, When the average value with the gradation level of the image signal input in the subsequent one frame is equal to or less than the threshold value, the image signal having the minimum or smaller gradation level is supplied to the image display unit, and the average value When the value is larger than the threshold value, the image display unit is supplied with a gradation level image signal that is increased or decreased according to the average value level, thereby achieving the above object.

  The display control program of the present invention is for causing a computer to execute each process of the image display method, thereby achieving the above object.

  The recording medium of the present invention is a computer-readable recording medium on which the display control program is recorded, whereby the above object is achieved.

  In each gradation level distributed before and after the time distributed in each subframe period, the distribution gradation level after the time may be equal to or less than ½ of the distribution gradation level before the time.

An image display method of the present invention is an image display method for supplying an image of an input image signal including at least a moving object part and a background part for display, wherein the frame period includes at least a subframe α period and a subframe β period. Including a step of supplying a gradation level of an input image signal to an image display unit, wherein both the moving object part and the background part have a luminance level of less than 50% of the maximum luminance. The minimum brightness level is provided at least in the subframe β period of the plurality of subframe periods, and if both the moving object part and the background part have a brightness level of 50% or more of the maximum brightness, the maximum value response when the brightness level of is supplied to at least subframe α period of the sub-frame period of the plurality of, display luminance increases If the response time when the display luminance decreases is shorter than the subframe α, the subframe α period is set as the second subframe of the one frame period. The α period is the first subframe in the one frame period , and the above object is achieved.

  The plurality of subframe periods may be two subframe periods.

  The method may further include displaying the input image signal at the supplied gradation level.

  The method may further include displaying the input image signal at the supplied gradation level.

  In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is set to the latter half of the one frame period. If the subframe is long, the subframe α period may be the first half of the one frame period.

  In the image display device of the present invention, in the image display unit, the response time when the display luminance decreases is shorter than the response time when the display luminance increases, and the subframe α period is the one frame period. An image display device for executing the above-described image display method, which is a sub-frame in the latter half of the above, and thereby achieves the above object.

  In the image display device of the present invention, in the image display unit, the response time when the display brightness decreases is longer than the response time when the display brightness increases, and the subframe α period is set to the one frame period. An image display device for executing the above-described image display method, which is the first half of the subframe, and achieves the above-described object.

An image display method of the present invention is an image display method for supplying an image of an input image signal including at least a moving object portion and a background portion for display, wherein the frame period is divided into a plurality of subframe periods, and the input image Supplying a gradation level of a signal to the image display unit, and the luminance level of the moving object supplied in the first subframe period is smaller than the luminance level supplied in the second subframe period, The luminance level of the background supplied in the first subframe period is also smaller than the luminance level supplied in the second subframe period, and the luminance level of the moving object supplied in the first subframe period is When the luminance level supplied in the second subframe period is larger than the luminance level supplied in the second subframe period, the luminance level of the background supplied in the first subframe period is also in the second subframe period. Are those greater than the supplied luminance level in the image display section, when compared to the response time in the case where the display luminance increases, the response time when the display luminance is lowered is short, The subframe α period is the second half subframe in the one frame period, and when this is long, the subframe α period is the first half subframe in the one frame period. The above object is achieved.

  The plurality of subframe periods may be two subframe periods.

  The method may further include displaying the input image signal at the supplied gradation level.

The image display device of the present invention is an image display device that displays an image of an input image signal including at least a moving object portion and a background portion, and has a plurality of subframes in which a frame period includes at least a subframe α period and a subframe β period. Means for supplying a gradation level of an input image signal divided into frame periods, and display means for displaying the image signal at the supplied gradation, wherein both the moving object part and the background part are maximum If the luminance level is less than 50% of the luminance, a minimum luminance level is provided in at least the subframe β period of the plurality of subframe periods, and both the moving object portion and the background portion are 50% of the maximum luminance. If it is more than the brightness level, which luminance level of the maximum value is supplied to at least subframe α period of the sub-frame period of the plurality of, In the display means, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is set to the second half of the one frame period. When the frame is long, the subframe α period is set to the first half of the one frame period, thereby achieving the above object.

  The plurality of subframe periods may be two subframe periods.

  In the display means, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is set to the second half of the one frame period. When the frame is long, the subframe α period may be the first half of the one frame period.

  In the image display unit, the response time when the display brightness decreases is shorter than the response time when the display brightness increases, and the subframe α period is set as the second subframe of the one frame period. Also good.

  In the image display unit, the response time when the display brightness decreases is longer than the response time when the display brightness increases, and the subframe α period is set as the first half of the one frame period. Also good.

An image display apparatus according to the present invention is an image display apparatus for supplying an image of an input image signal including at least a moving object part and a background part for display, wherein the frame period is divided into a plurality of subframe periods, and the input image Means for supplying a gradation level of the signal and display means for displaying the image signal at the supplied gradation, and the luminance level of the moving object supplied in the first subframe period is the second subframe. If the luminance level supplied during the period is smaller than the luminance level supplied during the first sub-frame period, the background luminance level supplied during the first sub-frame period is also smaller than the luminance level supplied during the second sub-frame period. When the luminance level of the moving object supplied in the frame period is larger than the luminance level supplied in the second subframe period, the back supplied in the first subframe period Luminance level are those greater than the luminance level supplied in the second sub-frame period, in the display unit, as compared to the response time in the case where the display luminance rises, if the display luminance is lowered When the response time of the subframe α is short, the subframe α period is set as the second subframe of the one frame period. When this is long, the subframe α period is set as the first subframe of the one frame period. It is intended to the frame, thereby the objective described above being achieved.

  The plurality of subframe periods may be two subframe periods.

The image display device of the present invention is an image display device that displays an image of an input image signal including at least a moving object portion and a background portion, and has a plurality of subframes in which a frame period includes at least a subframe α period and a subframe β period. A display control unit that is divided into frame periods and configured to supply a gradation level of an input image signal; and an image display unit configured to display the image signal at the supplied gradation. If both the moving object part and the background part have a luminance level less than 50% of the maximum luminance, a minimum luminance level is provided at least in the subframe β period of the plurality of subframe periods, and the moving object If both the portion and the background portion have a luminance level of 50% or more of the maximum luminance, the maximum luminance level is at least a level of the plurality of subframe periods. Is supplied to the frame α period, in the image display unit, compared to the response time in the case where the display luminance rises, if the response time when the display luminance is lowered is short, the said sub-frame α period In the latter half of one frame period, if it is long, the subframe α period is the first half of the one frame period, thereby achieving the above object. .

  The plurality of subframe periods may be two subframe periods.

  In the display means, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is set to the second half of the one frame period. When the frame is long, the subframe α period may be the first half of the one frame period.

  In the image display unit, the response time when the display brightness decreases is shorter than the response time when the display brightness increases, and the subframe α period is set as the second subframe of the one frame period. Also good.

  In the image display unit, the response time when the display brightness decreases is longer than the response time when the display brightness increases, and the subframe α period is set as the first half of the one frame period. Also good.

An image display apparatus according to the present invention is an image display apparatus for supplying an image of an input image signal including at least a moving object part and a background part for display, wherein the frame period is divided into a plurality of subframe periods, and the input image A display control unit configured to supply a gradation level of a signal; and an image display unit configured to display the image signal at the supplied gradation, and is supplied in a first subframe period When the luminance level of the moving object is smaller than the luminance level supplied in the second subframe period, the luminance level of the background supplied in the first subframe period is also supplied in the second subframe period. When the brightness level of the moving object supplied during the first subframe period is less than the brightness level supplied during the second subframe period. In the case where the luminance level of the background supplied in the first subframe period is also higher than the luminance level supplied in the second subframe period , and the display luminance is increased in the image display unit. If the response time when the display brightness decreases compared to the response time is short, the subframe α period is set as the second subframe of the one frame period. The frame α period is set as the first half subframe in the one frame period , and the above object is achieved.

  The plurality of subframe periods may be two subframe periods.

The image display method of the present invention is an image display method for supplying an image of an input image signal for display, wherein the frame period is divided into a plurality of subframe periods, and the gradation level of the input image signal is set to an image display unit. Supplying a maximum luminance value to at least one center of the plurality of subframes and a minimum luminance level to a subframe furthest from the center of the plurality of subframes ; The relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period is increased or decreased according to the input image signal so as to show an appropriate gamma luminance characteristic, and is changed in each subframe period. The gradation level of the supplied image signal is set, thereby achieving the above object.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level of the maximum luminance value may be supplied to at least one central subframe.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

  The method may further include displaying the input image signal at the supplied gradation level.

The image display method of the present invention is an image display method for supplying an image of an input image signal for display, wherein the frame period is divided into a plurality of subframe periods, and the gradation level of the input image signal is set to an image display unit. wherein the step of providing the, while lower than the heart outside of the sub-frame in the plurality of sub-frame luminance values of the gradation level, the gradation level of the input image signal, the display luminance in one frame period Is set to the gradation level of the image signal that is increased or decreased in accordance with the input image signal and supplied in each subframe period so that the relationship with the time integration amount indicates an appropriate gamma luminance characteristic , As a result, the above object is achieved.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level having the maximum luminance value may be supplied to at least one central subframe among the plurality of subframes.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

  The method may further include displaying the input image signal at the supplied gradation level.

An image display device according to the present invention is an image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods, and a gradation level of the input image signal is supplied. And a display means for displaying the input image signal at the supplied gradation level, supplying a maximum luminance value to at least one center of the plurality of subframes, and a minimum luminance level. A plurality of subframes are supplied to a subframe farthest from the center, and the relationship between the gradation level of the input image signal and the time integration amount of display luminance in one frame period shows an appropriate gamma luminance characteristic. As described above, the gradation level of the image signal that is increased or decreased according to the input image signal and is supplied in each subframe period is set, thereby achieving the above object.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level having the maximum luminance value may be supplied to at least one central subframe among the plurality of subframes.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

An image display device according to the present invention is an image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods, and a gradation level of the input image signal is supplied. A display control unit configured to display the image signal at the supplied gradation, and at least one of the plurality of subframes having a maximum luminance value. And supplying the minimum luminance level to the subframe farthest from the center of the plurality of subframes , and the display control unit displays the gradation level of the input image signal and the display in one frame period. The gradation level of the image signal that is increased or decreased according to the input image signal and supplied in each subframe period is set so that the relationship with the time integration amount of the luminance shows an appropriate gamma luminance characteristic. Ri, thereby the objective described above being achieved.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level having the maximum luminance value may be supplied to at least one central subframe among the plurality of subframes.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

An image display device according to the present invention is an image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods, and a gradation level of the input image signal is supplied. means for the input image signal and display means for displaying in the supplied gradation level, lower than the heart outside of the sub-frame in the plurality of sub-frame luminance values of the gradation levels In addition, the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period is increased or decreased according to the input image signal so as to show an appropriate gamma luminance characteristic. The gradation level of the image signal supplied during the period is set , thereby achieving the above object.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level having the maximum luminance value may be supplied to at least one central subframe among the plurality of subframes.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

An image display device according to the present invention is an image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods, and a gradation level of the input image signal is supplied. A display control unit configured to display the image signal at the supplied gradation, and the display control unit displays the luminance value of the gradation level. while lower than the heart outside of the sub-frame within the plurality of subframes, and the gradation level of the input image signal, the relationship between the time integrated amount of display luminance in one frame period, an appropriate gamma luminance characteristic As shown, the gradation level of the image signal that is increased or decreased in accordance with the input image signal and is supplied in each subframe period is set , thereby achieving the above object.

  When the gradation level is 50% or more of the maximum luminance level, the luminance level having the maximum luminance value may be supplied to at least one central subframe among the plurality of subframes.

  When the gradation level is less than 50% of the maximum luminance level, a minimum luminance level may be supplied to a subframe farthest from the center of the plurality of subframes.

  When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. It may be supplied to the central subframe.

  A program according to the present invention is a computer program for causing a computer to execute the image display method, and thereby achieves the above object.

  The recording medium of the present invention is a computer-readable recording medium having the computer program, thereby achieving the above object.

  The electronic device of the present invention is an electronic device that displays an image on the display screen of the display unit using the image display device, and thereby achieves the above object.

  The liquid crystal television apparatus of the present invention includes the image display device, and a tuner unit that enables the display control means of the image display device to output a television broadcast signal with a selected channel. Achieved.

The liquid crystal monitor device of the present invention includes the image display device, and a signal processing unit that can output a monitor image signal obtained by processing an external monitor signal to the display control means of the image display device. The above object is achieved.

  The operation of the present invention will be described below with the above configuration.

  In the present invention, in a hold-type image display device provided with a plurality of subframe periods in order to improve the degradation of moving image quality due to motion blur, display is performed as much as possible while suppressing the decrease in maximum luminance and contrast ratio as much as possible. The gradation level supplied in each sub-frame period is controlled so that the temporal gravity center position of the luminance does not move according to the change in the gradation level of the input image signal.

  For example, when displaying an image of one frame period by the total amount of time integration of luminance displayed in n (n is an integer of 2 or more) subframe periods, the subframe period closest to the center or the center in time To the sub-frame period close to the front and back, the maximum or sufficiently large gradation level (a gradation level greater than a predetermined value) is sequentially supplied within a range in which the input gradation signal does not exceed the corresponding luminance level. When the input gradation level is reached, a minimum or sufficiently small gradation level (a gradation level smaller than a predetermined value) is supplied for the remaining subframe period.

  Further, when n is an odd number of 3 or more, the maximum is sequentially increased from the m-th (= (n + 1) / 2) subframe period, which is the center subframe period, toward the subframe periods adjacent to the front and rear. Supply a sufficiently large gradation level, supply a gradation level that increases or decreases according to the input gradation level before and after that, and then supply a minimum or sufficiently small gradation level for the remaining subframe period . At this time, the gradation level supplied in each subframe period is determined by the magnitude relationship between the input gradation level and the threshold T.

  Further, when n is an even number equal to or greater than 2, the m1 (= n / 2) and m2 (= n / 2 + 1) th subframe periods (or subframe periods closest to the center) that are temporally centered. After supplying the maximum or sufficiently large gradation level sequentially from the subframe period to the adjacent subframe period, supplying the gradation level that is increased or decreased according to the input gradation level before and after that, A minimum or sufficiently small gray level is supplied in the remaining subframe period. At this time, the gradation level supplied in each sub-frame period is determined by the magnitude relationship between the input gradation level and the threshold value T.

  By such control, the temporal center of gravity position of the display luminance can be fixed at the temporal center of one frame period or a position closest to the center, so that the conventional image display disclosed in Patent Document 1 is performed. It is possible to suppress deterioration in image quality due to incorrect luminance or color balance, which occurs when the temporal gravity center position of display luminance changes according to input gradation in the apparatus. In addition, since the display luminance within one frame period changes appropriately, it is possible to improve the degradation of moving image quality due to motion blur that occurs in a conventional general hold-type image display device. Further, when the maximum gradation level is displayed, it is possible to suppress the decrease in the maximum luminance and the contrast ratio that occurs in the black insertion type image display device in which the minimum luminance display is always provided.

  When n is 2, assuming that one subframe period is a subframe α period and the other subframe is a subframe β period, the gradation level or the input gradation is maximized or sufficiently large in the subframe α period. A gradation level that is increased or decreased in response to this is supplied, and a gradation level that is increased or decreased according to an input gradation is supplied during the subframe β period. At this time, the gradation level supplied in each subframe period is determined based on the magnitude relationship between the input gradation level and the threshold value.

  By such control, it is possible to minimize the movement of the center of gravity position of the display luminance as much as possible. Therefore, in the conventional image display device disclosed in Patent Document 1, the temporal center of gravity of the display luminance is changed according to the input gradation. It is possible to suppress degradation of image quality due to incorrect luminance or color balance that occurs when the position changes greatly. In addition, since the display luminance within one frame period changes appropriately, it is possible to improve the degradation of moving image quality due to motion blur that occurs in a conventional general hold-type image display device. In addition, it is possible to suppress a decrease in the maximum luminance and the contrast ratio that occurs in a black insertion type image display device in which a minimum luminance display is provided even when the maximum gradation level is displayed.

  In addition, when n is 2, an image of a temporally intermediate frame is generated with respect to two consecutively input images, and the gradation level supplied during the subframe β period is The determination may be made based on the magnitude relationship between the gradation level of the intermediate frame image and the threshold value. In this case, since the temporally intermediate frame image is generated by estimation, an incorrect display due to an interpolation error that may occur in some pixels can be displayed without conspicuous.

  Further, when n is 2, the gradation level supplied in the subframe β period is determined by inputting the gradation level of the input image signal and the previous frame period or the next frame period. You may determine by the magnitude relationship between the value which averaged the gradation level, and a threshold value.

  In addition, the upper limit (maximum level) of the gradation level supplied in each subframe period is set so as to become smaller or the same in order from the center or the subframe period closest to the center toward the front and rear. Accordingly, a subframe period with low luminance can be provided even when the input gradation level is large. Thereby, even when the input gradation level is large, it is possible to improve the degradation of moving image quality due to motion blur that occurs in a conventional general hold-type image display device. Here, in the case of n = 2, the upper limit value of the gradation level supplied in one subframe period can be set to be equal to or higher than the upper limit value of the gradation level supplied in the other subframe period.

  Further, the gradation level and threshold value supplied during the subframe period can be set so that the input gradation level and the time integration amount of the luminance show the gamma luminance characteristics. As a result, a moving-image due to motion blur that occurs in a conventional general hold-type image display device while ensuring compatibility of gradation reproducibility with respect to a video signal created on the assumption of the gamma luminance characteristics of the CRT. Quality deterioration can be improved.

  In addition, a temperature detection unit that detects the panel temperature and the ambient temperature can be provided, and a gradation level and a threshold value to be supplied during the subframe period can be set (setting change) according to the detected temperature. As a result, even when using a display element such as a liquid crystal display element in which the balance between the speed at which the brightness increases and the speed at which it decreases depends on the temperature condition, the relationship of the display brightness with respect to the input image signal is kept constant. be able to.

  Furthermore, when the input image signal is composed of a plurality of color components, the ratio between the luminances displayed for each subframe period for the color component having the highest input gradation level is set to the other. The gradation levels can be supplied by matching the ratios between the luminances displayed for each sub-frame period for each of the color components.

  As a result, even when the luminance balance of each color component is greatly different, it is possible to prevent a phenomenon in which the balance of the color component is lost and an abnormal color is seen when displaying a moving image.

Here, various distribution methods for distributing the luminance levels assumed by the input image signal in each subframe period will be described in association with the contents of the claims. Although described later in detail, the gradation level is adjusted so that the luminance level assumed by the input image signal is obtained.

  Further, in the following description, in order to explain the distribution method in an easy-to-understand manner, the distribution method when the gradation level of the input image signal is gradually increased from a low level to a predetermined gradation level is described. According to the invention, according to the gradation level of the input image signal, based on the following distribution method, the distribution is instantaneously performed by a conversion process using a calculation process or a lookup table.

  As shown in FIG. 67 (a), an input image signal is assumed for each subframe from the temporal center of one frame period or the subframe closest to the center until the preceding and succeeding subframes become full. The brightness levels are sorted sequentially. The remaining luminance level is distributed to the remaining subframes so that the luminance level is assumed to be the same as that assumed for the input image signal, and the distribution of the luminance level is completed.

  As shown in FIG. 67 (b), the luminance assumed by the input image signal in two subframes simultaneously from one subframe at the temporal center of one frame period until the next and subsequent subframes are filled sequentially. Assign levels. At this time, the luminance level of the input image signal is sequentially distributed to the subframes to fill up, and the reference value of the gradation level corresponding to the luminance level when distributing to the next subframe is the threshold value. The remaining luminance level is distributed to the next two subframes so that the input image signal is the same as the assumed luminance level, and the distribution of the luminance level is completed.

  As shown in FIG. 67 (c), it is assumed that the input image signal is simultaneously input from two subframes at the center of one frame period at the same time, two subframes at a time until the subframes before and after are sequentially filled. Assign brightness levels. At this time, the luminance level assumed by the input image signal is filled up in two subframes in order and filled up, and the reference value of the gradation level corresponding to the luminance level when distributing to the next left and right subframes Is the threshold. The remaining luminance level is distributed to the next two subframes so that the input image signal is the same as the assumed total luminance level, and the distribution of the luminance level is completed.

  As shown in FIG. 67 (d), the luminance level assumed by the input image signal is allocated from one of the two subframes (dot portion). When one of the subframes is full (shaded portion; threshold T), the luminance level assumed by the input image signal is assigned to the other subframe (dot portion).

  As shown in FIG. 68A, the luminance level assumed by the input image signal is assigned from one of the two subframes (dot portion). When the gradation level of the input image signal reaches the threshold value T1, the luminance level assumed by the input image signal is also allocated to the other subframe at the same time (dot portion). In one subframe, the distribution of the luminance level is full (threshold value T2), and the remaining luminance level assumed by the input image signal is distributed to the other subframe and the process ends (dot portion).

As shown in FIG. 68 (f), the luminance level assumed by the input image signal is allocated from one of the two subframes (dot portion). When the gradation level of the input image signal reaches the threshold value T1 in one of the subframes, it is temporarily fixed (distribution stopped) in the middle, and the luminance level assumed by the input image signal is assigned to the other subframe (dot portion). . When the distribution of the luminance level assumed by the input image signal in the other subframe is full (threshold value T2), the luminance level distribution fixing to one subframe is canceled, and the input image is input to one subframe. The remainder of the luminance level assumed by the signal is allocated and the process ends (dot portion).

  As shown in FIG. 68 (g), the luminance level assumed by the input image signal is distributed from one of the two subframes (dot portion). When the gradation level of the input image signal reaches the threshold value T, one of the subframes has the maximum luminance, and the other subframe has an image difference (motion) between the input image of the main frame and the input image of the next frame. ), If the difference has changed, the remaining luminance level is adjusted so that the input image signal in the temporally intermediate state (estimated image between) of the preceding and following images becomes the expected luminance level. Distribute. In one of the subframes, the distribution of luminance levels assumed by the input image signal is full.

  As shown in FIG. 68 (h), the luminance level assumed by the input image signal is allocated from one of the two subframes (dot portion). When the gradation level corresponding to the distribution luminance level reaches the threshold value T, one subframe is set to the maximum luminance, and the average value of the input image of the main frame and the input image of the next frame is calculated in the other subframe. Then, the remaining luminance level assumed by the average input image signal is distributed. In one of the subframes, the distribution of the luminance level assumed by the input image signal is full.

  As shown in FIGS. 69 (i) and 69 (j), each subframe period is different or the same. As the subframe period is narrower, the impulse effect is obtained, and when the subframe period width is thick, the luminance center of gravity approaches the thick subframe period and becomes difficult to move.

  As shown in FIG. 69 (k), when the distribution luminance level is filled from one subframe and the threshold value T1 is reached, the distribution luminance level is also filled in the other subframe at the same time. This is a case in which the difference between the tone level or the luminance level is distributed so as to be a constant value.

  As shown in FIG. 69 (l), when the luminance level is filled from one subframe and the threshold value T1 is reached, the distributed luminance level is filled in the other subframe at the same time. This is a case where distribution is performed such that the difference in level or luminance level is a value according to a predetermined function (such as a value multiplied by a predetermined coefficient).

  As shown in FIG. 70 (m), when the response time of the liquid crystal at the time of increasing the luminance is greater than the response time of the liquid crystal at the time of decreasing the luminance, the luminance level is assigned first from the second subframe, and the response of the liquid crystal when the luminance is increased. In the case of time <the response time of the liquid crystal when the luminance decreases, the luminance level is allocated first from the first subframe.

  As shown in FIG. 70 (n), when the display brightness response time when the display brightness level changes from Lmin to Lmax> the display brightness response time when the display brightness level changes from Lmax to Lmin, the brightness level is set first from the latter subframe. In the case of display luminance response time at the time of distribution and display luminance level change from Lmin to Lmax <display luminance response time at the time of change from Lmax to Lmin, the luminance level is distributed first from the first half subframe.

  As shown in FIG. 70 (o), the luminance level assumed by the input image signal is allocated from one of the two subframes (dot portion). When one of the subframes reaches the upper limit L (shaded portion; threshold T), the luminance level assumed by the input image signal is assigned to the other subframe (dot portion).

As shown in FIG. 70 (p), the luminance level assumed by the input image signal is distributed from the temporally subframe of one frame period (dot portion). When the center subframe reaches the highest upper limit L1 (shaded portion; threshold T1), the luminance level assumed by the input image signal is assigned to the left and right subframes of the center subframe at the same time (dot portion). . When the gradation level corresponding to the distributed luminance level of the two left and right subframes reaches the next highest upper limit L2 (shaded portion; threshold T2), the luminance is simultaneously applied to the left and right subframes of the left and right subframes simultaneously. The level is distributed to the upper limit L3 having the lowest luminance level (dot portion).

  As shown in FIG. 71 (q), the luminance level assumed by the input image signal is allocated from one of the two subframes (dot portion). When the gradation level corresponding to the distributed luminance level of one of the sub-frames is a high upper limit L1 (shaded portion; threshold T), the luminance level is assigned to the other sub-frame and the gradation level corresponding to this luminance level. To the lower upper limit L2 (dot portion).

  As shown in FIG. 71 (r), the luminance level is determined from one of the temporal center of one frame period or the subframe closest to the center so that the integrated value of the display luminance reproduces an appropriate gamma luminance characteristic. Then, the luminance level assumed by the input image signal is distributed (dot portion). When that subframe is full (the shaded area), the input image signal is assumed by determining the brightness level so that the integral value of the display brightness reproduces the appropriate gamma brightness characteristics in the other subframe closest to the center. The brightness level is distributed (dot portion). Furthermore, when the subframe is full (shaded area), the luminance level is set so that the integral value of the display luminance reproduces the appropriate gamma luminance characteristics in the empty subframe adjacent to the other subframe closest to the center. And the luminance level assumed by the input image signal is distributed (dot portion). Furthermore, when the subframe is full (shaded area), the luminance level is set so that the integral value of the display luminance reproduces the appropriate gamma luminance characteristics in the empty subframe adjacent to the subframe closest to the center. And the luminance level assumed by the input image signal is distributed (dot portion). By repeating this in sequence, the luminance level assumed by the input image signal to the image display unit is sequentially allocated from the center or the closest subframe to the left and right subframes.

  As shown in FIG. 71 (s), an input image signal is assumed by determining a luminance level so that an integral value of display luminance reproduces an appropriate gamma luminance characteristic from a temporally subframe of one frame period. The brightness level is distributed (dot portion). When the center subframe is full (shaded area; threshold T1), the luminance level is adjusted so that the integral value of the display brightness reproduces the appropriate gamma luminance characteristics at the same time on the left and right subframes of the center subframe. The luminance level assumed by the input image signal is confirmed and assigned (dot portion). When the two left and right subframes are full (shaded area; threshold value T2), the integral value of the display luminance is reproduced at the same time in the left and right subframes of the left and right subframes so that the appropriate gamma luminance characteristics are reproduced. The luminance level is determined and the luminance level assumed by the input image signal is distributed (dot portion). By sequentially repeating this, the luminance level assumed for the input image signal to the image display unit is sequentially assigned from the center subframe to the left and right subframes.

According to the image display device, the image display method, the program, and the recording medium of the present invention, when the luminance level of the moving object supplied in the first subframe period is smaller than the luminance level supplied in the second subframe period. The background luminance level supplied during the first subframe period is also made smaller than the luminance level supplied during the second subframe period. Further, when the luminance level of the moving object supplied in the first subframe period is higher than the luminance level supplied in the second subframe period, the background luminance level supplied in the first subframe period is also the second. It is made larger than the luminance level supplied during the sub-frame period. Therefore, it is possible to improve the degradation of moving image quality due to motion blur that occurs in a conventional general hold-type image display device. Further, when the maximum gradation level is displayed, it is possible to suppress the decrease in the maximum luminance and the contrast ratio that occurs in the black insertion type image display device in which the minimum luminance display is always provided.

  According to the image display device and the image display method of the present invention, in an image display device that displays an image for one frame period by the total amount of time integration of luminance displayed in a plurality of subframe periods, the image display apparatus supplies each subframe period. By controlling the gradation level of the image signal to be displayed, the amount by which the temporal center of gravity position of the image display luminance moves in accordance with the gradation level of the input image signal can be suppressed as much as possible during moving image display. This makes it possible to observe the incorrect luminance observed because the temporal center of gravity of the image display luminance greatly depends on the gradation level of the input image signal when moving images are displayed while minimizing the decrease in maximum luminance and contrast ratio. In addition, image quality deterioration due to color balance is suppressed. Further, it is possible to improve the degradation of moving image quality due to motion blur, which has been a problem in the conventional hold-type image display device.

  Further, according to the image display device and the image display method of the present invention, each sub-image is displayed so that the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period shows an appropriate gamma characteristic. A gradation level of an image signal supplied during the frame period and a threshold value that is a determination criterion thereof are set. As a result, it is possible to improve the degradation of moving image quality due to motion blur while ensuring the compatibility of gradation reproducibility with respect to the conventional video signal created on the assumption of the gamma luminance characteristics of the CRT.

  Further, according to the image display device and the image display method of the present invention, the gradation level of the image signal supplied during each subframe period and the threshold value as the determination criterion are set according to the panel temperature or the ambient temperature. The As a result, even when using a display element such as a liquid crystal display element in which the balance between the speed at which the brightness rises and the speed at which it falls depends on the temperature conditions, the relationship between the display brightness and the input image signal is kept constant. Can keep.

  Embodiments 1 to 12 of the image display device of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a basic configuration in Embodiments 1 to 8 of the image display apparatus of the present invention.

  In FIG. 1, an image display device 1 includes a display panel 10 constituting image display means (image display unit), a temperature sensor IC 20 as temperature detection means for detecting the panel temperature or its surrounding temperature, and an image for one frame. Is stored in the frame memory 30 as a frame data storage means, and a controller LSI 40 as a display control means for controlling each part.

  The display panel 10 includes a display element array 11, a TFT substrate 12, source drivers 13a to 13d, and gate drivers 14a to 14d.

  In the display element array 11, a plurality of display elements 11a (pixel portions) using a liquid crystal material or an organic EL (electroluminescence) member are arranged in a matrix.

In the display area of the TFT substrate 12, pixel electrodes 12a for driving these display elements 11a and TFTs 12b as switching elements for turning on / off the charge supply (display voltage) to the pixel electrodes 12a are provided in each display element 11a. Correspondingly, they are arranged in a matrix. In the periphery of the display area of the display element array 11 and the TFT substrate 12, four first to fourth source drivers 13a to 13d for driving the pixel electrode 12a and the display element 11a through the TFTs 12b, respectively. And four first to fourth gate drivers 14a to 14d for driving each TFT 12b.

  In the display region of the TFT substrate 12, a plurality of source voltage lines connected to the source driver and supplied with a source voltage (display voltage), and a plurality of source voltage lines connected to the gate driver and supplied with a gate voltage (scanning signal voltage). The gate voltage lines are provided so as to cross each other (orthogonal). A pixel electrode 12a and a TFT 12b are provided near each intersection. The gate electrode of the TFT 12b is connected to the corresponding gate voltage line (the gate voltage line at the intersection), and the source electrode of the TFT 12b is connected to the corresponding source voltage line (the source voltage line at the intersection). The drain electrode is connected to the pixel electrode 12a. Here, the leftmost source voltage line for each source driver (first to fourth source drivers 13a to 13d) is referred to as a first source voltage line, the right adjacent to it is referred to as a second source voltage line, and so on. The rightmost source voltage line is referred to as the final source voltage line. Similarly, the upper gate voltage line for each gate driver is called a first gate voltage line, the lower neighbor is called a second gate voltage line, and thereafter the lower gate voltage line is called a final gate voltage line. I will decide.

  In FIG. 1, in order to simplify the description, the first source voltage line connected to the first source driver 13a, the first gate voltage line connected to the first gate driver 14a, and the first gate voltage line are connected to these. Only the TFT 12b, the pixel electrode 12a connected to the TFT 12b, and the display element 11a corresponding to the pixel electrode 12a are exemplarily shown, and the others are omitted.

  In the vicinity of the display panel 10, a temperature sensor IC 20 having a function of detecting the temperature of the display panel 10 or its surroundings and outputting it as a temperature level signal is mounted. A frame memory 30 for holding the input image signal is also mounted. Further, various signals are output to the source drivers 13a to 13d and the gate drivers 14a to 14d, and data access to the frame memory 30 is performed, and a temperature level signal output from the temperature sensor IC 20 is read and brightness corresponding to the temperature is read. A controller LSI 40 that performs correction control is also mounted.

  A basic image display method will be described as an operation of the image display device 1 with the above-described configuration.

  First, from the controller LSI 40, image signals displayed on each pixel portion for one horizontal line are sequentially transferred to the first source driver 13a in synchronization with the clock signal. Since the first to fourth source drivers 13a to 13d are connected as shown in FIG. 1, one horizontal pixel is supplied to the first to fourth source drivers 13a to 13d by a pulse of the clock signal corresponding to the number of horizontal pixels. Several minutes of image signals are temporarily held. In this state, when a latch pulse signal is output from the controller LSI 40 to the source drivers 13a to 13d, the display voltage level corresponding to the image signal of each pixel unit from each source driver 13a to 13d is the source voltage corresponding to the number of horizontal pixels. Output to the line.

The controller LSI 40 outputs an enable signal, a start pulse signal, and a vertical shift clock signal as control signals to the gate drivers 14a to 14d, respectively. While the enable signal is at a low level, the gate voltage line is turned off. When the enable signal is at a high level and the start pulse signal is input at the timing of the rising edge of the vertical shift clock signal, the first gate voltage line of the corresponding gate driver is turned on. Further, when the start pulse signal is not input at the timing of the rising edge of the vertical shift clock, the gate voltage line next to the gate voltage line that was previously turned on is turned on.

  During the period when the display voltage for one horizontal pixel is output to the source voltage line, one gate voltage line is turned on, so that each horizontal pixel connected to the gate voltage line is turned on. The TFT 12b is turned on. As a result, charges (display voltages) from the respective source voltage lines are respectively supplied to the pixel electrodes 12a for one horizontal pixel, whereby the state of the display element 11a is changed and image display is performed. By repeating the display control as described above for each horizontal line, an image is displayed on the entire display screen.

  The specific embodiments 1 to 8 of the controller LSI 40 of the image display apparatus 1 and the image display method using the controller LSI 40 according to the present invention will be described below in detail on the premise of the image display apparatus having the above configuration.

(Embodiment 1)
In the first embodiment, for each of the pixel portions on the screen, an image display for one frame period is performed by the total amount of time integral values of luminance displayed in the first and second half subframe periods. In one subframe period (for example, the first half of the subframe period), a maximum gradation level or a gradation level that is increased or decreased in accordance with the gradation level of the input image signal is supplied, and this subframe is subdivided. This is called a frame α, and in the other subframe period (for example, the second subframe period), a gradation level that is increased or decreased according to the minimum gradation level or the gradation level of the input image signal is supplied. A case where the frame β is called will be described. These controls are performed on a pixel unit basis (one pixel or every predetermined number of pixels).

  Note that whether to assign these subframe α and subframe β to the first half subframe or the second half subframe will be described later.

  Further, the display panel 10 used in the first embodiment uses a liquid crystal panel using a liquid crystal material whose response speed is highly temperature dependent as a display element.

  FIG. 2 is a block diagram showing the first embodiment of the controller LSI 40 of FIG.

  As shown in FIG. 2, the controller LSI 40A as display control means of the first embodiment includes a line buffer 41 as line data storage means, a timing controller 42 as timing control means, and a frame as frame storage data selection means. Memory data selector 43, first gradation conversion circuit 44 as first gradation conversion means, second gradation conversion circuit 45 as second gradation conversion means, and output data selector 46 as output data selection means And.

  The line buffer 41 receives the inputted input image signal for each horizontal line and temporarily holds it. The line buffer 41 includes a reception port and a transmission port independently, and can perform reception and transmission at the same time.

  The timing controller 42 controls the frame memory data selector 43 to alternately switch the timing of data transfer to the frame memory 30 and data reading from the frame memory 30. In addition, the timing controller 42 selects and controls each output timing alternately from the first gradation conversion circuit 44 and the second gradation conversion circuit 45 with respect to the output data selector 46. That is, the timing controller 42 causes the output data selector 46 to switch between the first half subframe period and the second half subframe period, which will be described later.

  The frame memory data selector 43 is controlled by the timing controller 42 to transfer the input image signal held in the line buffer 41 by one horizontal line to the frame memory 30 and to input the frame memory one frame before. The image signal stored in the memory 30 is alternately selected to read out one horizontal line at a time, and the read data is transferred to the second gradation conversion circuit 45.

  The first gradation conversion circuit 44 converts the gradation level of the input image signal supplied from the line buffer 41 into a gradation level that is increased or decreased according to the maximum gradation level or the gradation level of the input image signal. The

  The second gradation conversion circuit 45 converts the gradation level of the image signal supplied from the frame memory data selector 43 into a gradation level that is increased or decreased according to the minimum gradation level or the gradation level of the input image signal. Is done.

  The first gradation conversion circuit 44 and the second gradation conversion circuit 45 have a function of changing the conversion value in accordance with the temperature level signal output from the temperature sensor IC 20. In the first embodiment, the first gradation conversion circuit 44 and the second gradation conversion circuit 45 are configured by a lookup table in which output values corresponding to input values are stored in advance. The output value can also be calculated and output by.

  The output data selector 46 is controlled by the timing controller 42 and alternately selects the image signal output from the first gradation conversion circuit 44 and the image signal output from the second gradation conversion circuit 45 for each line. And output as a panel image signal.

  The operation of the image display apparatus using the controller LSI 40A of the first embodiment with the above configuration will be described.

  FIG. 3 is a diagram illustrating the flow of the image signal for each horizontal period in the image display apparatus according to the first embodiment. Here, a period during which the image signals of the first to third lines of the Nth frame are input is shown.

  In FIG. 3, the parentheses [] indicate image signal transfer periods for one horizontal line. For example, [f, l] indicates that the input image signal input to the horizontal l-th line of the f-th frame is transferred, and [N, 2], for example, is transferred to the second horizontal line of the N-th frame. It shows that the input image signal is being transferred. The M-th line indicates an intermediate line of the screen, and in the first embodiment, the M-th line is a horizontal line driven by the first gate voltage line of the third gate driver 14c. Also, C1 transfers the image signal converted by the first gradation conversion circuit 44 using the input image signal of the frame and horizontal line shown in [] behind it as a source, and C2 receives [] after it. It shows that the image signal converted by the second conversion circuit 45 is transferred using the input image signal of the frame and horizontal line shown in FIG.

  First, as indicated by an arrow D1 in FIG. 3, the input input image signal is received by the line buffer 41.

  Next, as indicated by an arrow D2, from the middle of receiving an image signal for one line, writing from the line buffer 41 to the frame memory 30 via the frame memory data selector 43 and the first from the line buffer 41 are performed. Transfer to the gradation conversion circuit 44 is performed. The converted image signal is output from the first gradation conversion circuit 44 as a panel image signal.

  Also, as indicated by an arrow D3, the image signal of the horizontal line that is past half a frame from the line of the image signal to be written is read from the frame memory 30 line by line alternately with the writing to the frame memory 30. Then, it is converted by the second gradation conversion circuit 45 via the frame memory data selector 43 and output as a panel image signal.

  Further, when a panel image signal for one horizontal line output from the controller LSI 40 is transferred to the first to fourth source drivers 13a to 13d by a clock signal and then a latch pulse signal is applied, each source voltage line receives each A display voltage corresponding to the display luminance of the pixel portion is output. At this time, a vertical shift clock signal or a gate start pulse signal is supplied to the gate driver corresponding to the line on which an image is displayed by supplying charges (display voltage) on the source voltage line, as appropriate. The scanning signal of the gate voltage line is turned on. On the other hand, in the gate driver that does not display an image, the enable signal is set to the low level and the scanning signal of the gate voltage line is turned off.

  In the example of FIG. 3, as indicated by an arrow D4, after the image signal for one horizontal line of the Mth line of the (N−1) th frame is transferred to the source driver, the controller LSI 40 sends the image signal as indicated by an arrow D5. The enable signal to the third gate driver 14c is set to the high level, and the start pulse signal and the vertical shift clock signal to the third gate driver 14c are supplied as indicated by arrows D6 and D7. As a result, as indicated by an arrow D8, the TFT 12b connected to the first gate voltage line of the third gate driver 14c whose display position corresponds to the Mth line on the screen is turned on, and an image is displayed. At this time, the enable signals to the first, second, and fourth gate drivers 14a, 14b, and 14d that do not correspond to the display position are turned off, and the TFT 12b connected to the gate voltage line is turned off. .

  Next, as shown by the arrow D9, after the image signal for one horizontal line of the first line of the Nth frame is transferred to the source driver, the controller LSI 40 sends the first gate driver 14a as shown by the arrow D10. As shown by arrows D11 and D12, a start pulse signal and a vertical shift clock signal are supplied to the first gate driver 14a. As a result, as indicated by an arrow D13, the TFT 12b connected to the first gate voltage line of the first gate driver 14a whose display position corresponds to the first line of the screen is turned on, and an image is displayed. At this time, the enable signal to the second to fourth gate drivers 14b to 14d not corresponding to the display position is set to the off level, and the TFT 12b connected to the gate voltage line is set to the off state.

  FIG. 4 is a diagram showing how the image signal on the screen is rewritten by repeating the display control as shown in FIG. Here, a state is shown in which the image display is rewritten during the period in which the image signals of the Nth frame and the (N + 1) th frame are input.

  The diagonal arrows shown in FIG. 4 indicate the vertical position at which one line of image rewriting is performed and the rewriting timing. Ci [f] indicates that the image signal of the f-th frame is displayed by the image signal converted by the i-th gradation conversion circuit (44 or 45). Next, the image on the same line is displayed. Image display information is held until rewriting is performed. In FIG. 4, the position where the image display information converted by the first gradation conversion circuit 44 is held is white (no hatching), and the image display information converted by the second gradation conversion circuit 45 is held. The position is shown as gray (with hatching). Dotted lines indicate the boundary positions of the driven gate drivers (first gate drivers 14a to 14d).

Paying attention to the vertical position of one horizontal line on the screen, the display is performed by the image signal obtained by converting the input image signal by the first gradation conversion circuit 44 during the half of the input 1 frame period length. It can be seen that during the next half period, display is performed using an image signal obtained by converting the input image signal of the same frame by the second gradation conversion circuit 45. Each half of the input one frame period is referred to as a first half subframe period and a second half subframe period.

  Whether to assign the subframe α and the subframe β to the first half subframe or the second half subframe is determined according to the luminance response characteristic of the display panel to be used.

  The display panel used in Embodiment 1 has a long response time when switching from the minimum luminance level to the maximum luminance level, and the response is insufficient in one subframe period, but conversely the maximum luminance level. The display panel has a luminance response characteristic in which the response time for switching from the minimum luminance level to the minimum luminance level is short and the luminance response is almost completed in one subframe period.

  Using such a display panel, when the gradation level of the input image signal changes as shown in FIG. 5, the subframe α period is assigned to the first half subframe and the subframe β period is assigned to the second half subframe. FIG. 6 shows how the display brightness changes in the display panel.

  In FIG. 6, the largest change in gradation level is in the first half subframe when the input image signal has greatly increased as shown by arrow D37-1, but it is used in the first embodiment as described above. The display panel has a long response time when switching from the minimum luminance level to the maximum luminance level, and the response is insufficient in one subframe period. At the end of the first subframe indicated by the arrow D37-2, the luminance response is displayed. Becomes incomplete, and the state of the luminance change is different from that of the subsequent frame that should have the same input gradation level. In such a case, in an actual image, a pseudo contour may occur at the edge of a moving object, or in the case of color display, the color balance with other color components may be lost and an abnormal color may be seen.

  Next, when the gradation level of the input image signal changes as shown in FIG. 5 when subframe α is assigned to the second half subframe and subframe β is assigned to the first half subframe, the display luminance on the display panel is changed. This change is shown in FIG.

  In FIG. 7, the largest change in gradation level is in the first half sub-frame when the input image signal changes downward as indicated by arrow D38-1, but as described above, it is used in the first embodiment. The display panel has a short response time when switching from the maximum luminance level to the minimum luminance level, and the response is almost completed in one subframe period. For this reason, since the luminance response is sufficient at the end time of the first half subframe indicated by the arrow D38-2 and the state of the luminance change is the same as that of the subsequent frame having the same input gradation level, the edge of the moving object In this case, there is no occurrence of a pseudo contour in the area, or in the case of color display, the color balance with other color components is lost and an abnormal color is not seen. Therefore, in the first embodiment, the subframe α is assigned to the second half subframe and the subframe β is assigned to the first half subframe.

  Here, the image display method of the first embodiment will be described.

  In the image display method according to the first embodiment, the second half subframe is called a subframe α, and the gradation of the input image signal to be input when the gradation level of the input image signal is equal to or less than a uniquely determined threshold value. An image signal with a gradation level that is increased or decreased according to the level is supplied, and an image signal with the maximum gradation level is supplied when the gradation level of the input image signal is greater than a threshold value. In addition, the image signal is converted by the first gradation conversion circuit 44.

  Also, the first half subframe is called a subframe β, and when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value, an image signal with the minimum gradation level is supplied. When the gradation level of the input image signal is greater than the threshold value, the second gradation conversion circuit 45 supplies an image so that an image signal with a gradation level that is increased or decreased according to the input image signal is supplied. The signal is converted.

  Here, a luminance value that is a setting target in the first half subframe period and the second half subframe period will be described.

  FIG. 8 is a diagram for explaining target setting of display luminance values in the first embodiment.

  In FIG. 8, the left column shows the assumed luminance value of the input image signal, and the center column shows the display luminance in the first half subframe period and the second half subframe period in the first embodiment. The right column shows values obtained by time-integrating the luminance values of two subframe periods in one input frame period. This is considered to correspond to the brightness that is actually perceived by the observer's eyes, but here, the maximum capability value obtained by time-integrating the luminance in the display panel 10 is 100%. From the upper part of FIG. 8, the case where the luminance values assumed for the input image signal based on the gamma luminance characteristics are 0%, 25%, 50%, 75% and 100%, respectively.

As shown in FIG. 8, there is a case where the assumed luminance of the input image signal is ½ (50%) of the maximum luminance as a threshold for determining the gradation level of the image signal supplied in each subframe period. Is set. When the assumed luminance of the input image signal is 1/2 (50%) or less of the maximum luminance, the luminance in the latter half subframe period is
[Luminance in the second half subframe period]
= [Assumed luminance of input image signal] x 2
(Predetermined ratio; multiplication value 2) is increased or decreased according to the assumed luminance of the input image signal. For example, when the assumed luminance of the input image signal is 25% of the maximum luminance, the luminance in the latter half subframe period is 25% × 2 = 50%.

  Further, when the assumed luminance of the input image signal is larger than ½ (50%) of the maximum luminance, the luminance in the latter half subframe period is set to the maximum luminance (100%).

  On the other hand, the luminance of the first sub-frame is set to the minimum luminance (0%) when the assumed luminance of the input image signal is 1/2 (50%) or less of the maximum luminance.

Also, if the assumed luminance of the input image signal is greater than 1/2 (50%) of the maximum luminance,
[Luminance in the first half subframe period]
= ([Assumed luminance of input image signal] × 2-1
(Predetermined ratio; multiplication value 2) is increased or decreased according to the assumed luminance of the input image signal. For example, when the assumed luminance of the input image signal is 75% of the maximum luminance = 3/4, the luminance in the first half subframe period is (3/4) × 2-1 = 50%.

  Thus, the gradation level of the input image signal is converted by the first gradation conversion circuit 44 (first half subframe period) and the second gradation conversion circuit 45 (second half subframe period) according to the set luminance value. And output in the first half subframe period and the second half subframe period, respectively. As a result, the temporal center-of-gravity position of the display luminance is fixed in the second half subframe period without depending on the gradation level of the input image signal, and therefore, illegal as in the prior art disclosed in Patent Document 1. Image quality deterioration due to the brightness and color balance can be suppressed.

By the way, television broadcasting, video playback signal and PC (personal computer)
Most of the current general image signals such as the image output are generated and output on the assumption of the gamma luminance characteristics possessed by a CRT (cathode ray tube) which has been the main image display device in the past. In this case, the relationship between the gradation level of the image display signal and the display luminance assumed by the gradation level is not a linear relationship. For this reason, in order to realize appropriate gradation expression even with a display element such as a liquid crystal display element or an EL display element, a gamma luminance similar to that of a CRT is provided in a circuit unit that converts an image signal into a source voltage in a source driver. It is common to use what has a characteristic.

  For example, in the first embodiment, the relationship between the assumed gradation level of the input image signal and the luminance value is as follows.

[Display luminance] = ([Image signal gradation level] / [Maximum gradation level]) ^γ
(Γ = 2.2) (Formula 1)
(However, the maximum value of display brightness is represented by “1” and the minimum value is represented by “0”)
In the first embodiment, the source drivers 13a to 13d of the display panel 10 simply display an image signal for one frame input in a single frame period in the same manner as a general hold type display device. In addition, it is designed with the same gamma luminance characteristic as that of the above equation 1 so that the relationship between the gradation level and the luminance assumed by the input image signal can be reproduced. At this time, the relationship between the gradation level of the image signal and the luminance value is as shown in FIG.

  Even when the image display of one frame period is configured by two subframe periods as in the first embodiment, it is preferable that the relationship between the gradation level and the luminance value assumed by the input image signal can be reproduced.

  Therefore, in the first embodiment, in each subframe period, the relationship between the gradation level of the input image signal to be input and the time integration amount of the display luminance in one frame period shows an appropriate gamma luminance characteristic. A threshold value that is a criterion for determining the gradation level of the image signal and a gradation level of the image signal that is increased or decreased according to the input image signal and supplied in each subframe period are set.

  In the first embodiment, priority is given to suppressing reduction in luminance over improvement of motion blur for all gradation levels. When the gradation level of the input image signal is maximum, display is performed. It is an image display device that displays at the brightness level of the maximum capacity of the panel.

  In this case, the relationship between the gradation level of the input image signal, the gradation level supplied in the first half subframe period, and the gradation level supplied in the second half subframe period is expressed by the following equation.

(Input gradation / maximum gradation) ^γ
= {(First half gradation / maximum gradation) ^γ + (second half gradation / maximum gradation) ^γ } / 2
(Γ = 2.2) (Formula 2)
FIG. 9 is a diagram showing the relationship between the gradation level of the input image signal satisfying the relationship of the above expression 2 and the gradation level supplied in the first half and second half subframe periods.

  In FIG. 9, the left column indicates the gradation level of the input image signal to be input, and the center column converts the gradation level of the input image signal and is supplied in the first and second subframe periods. Indicates the key level. Further, as a result, the right column shows the luminance that is time-integrated in one frame period, and the time integration of the displayed luminance is 0%, 25%, 50%, and 75% from the upper part of FIG. And the case of 100% is shown.

  As shown in FIG. 9, as a threshold for determining the gradation level of the image signal supplied in each subframe period, the assumed luminance of the input image signal is 50% of the maximum luminance, that is, the gradation level of the input image signal. Is set to 72.97%. When the gradation level of the input image signal is 72.97% or less, the gradation level of the image signal supplied in the second half subframe period is assumed for the input image signal so as to satisfy the relationship shown in Equation 2 above. It is increased or decreased according to the brightness. Further, the gradation level of the image signal supplied in the first half subframe period is set to the minimum level 0 (%).

  On the other hand, when the gradation level of the input image signal is 72.97% or more, the gradation level of the image signal supplied in the second half subframe period is set to the maximum level (100%), and the gradation level of the first half subframe period is set. The gradation level of the supplied image signal is increased / decreased according to the assumed luminance of the input image signal so as to satisfy the relationship shown in Equation 2 above.

  Here, the gradation level of the image signal supplied in the first half subframe period is output from the line buffer 41 in which the input image signal is temporarily stored, and is converted by the first gradation conversion circuit 44 in the control LSI 40. Value. Further, the gradation level of the image signal supplied in the latter half subframe period is read from the frame memory 30 in which the input image signal is temporarily stored and converted by the second gradation conversion circuit 45 in the control LSI 40. Value.

  When the converted gradation levels are supplied as shown in the center column of FIG. 9, the source driver of the display panel 10 has the above-described equation 1 and FIG. 54 in each of the first and second half subframe periods. An image is displayed with a luminance according to the gamma luminance characteristics.

  As a result, as the brightness perceived by the observer's eyes, the value obtained by time-integrating the display luminance in the first half and the second half subframe period in one frame period is shown in the right column of FIG. The luminance value time-integrated in one frame period reproduces the gamma luminance characteristic assumed by the input image signal as shown in the above equation 1 and FIG. 54 with respect to the gradation level of the input image signal. ing. Thereby, it can be seen that an appropriate gamma characteristic is realized by the image display apparatus and the image display method of the first embodiment.

  In addition, in the image display apparatus according to the first embodiment in which image display is performed by the image display method as described above, an input image that is input when an image in which an object moves in a horizontal direction on a stationary background is displayed. When the gradation level of the signal is sufficiently small, the minimum gradation level is supplied in the second half subframe period in both the stationary background display section and the moving object display section. As in the case of the image display device of the black insertion method shown in FIG. 50 and FIG. 51, the motion blur is reduced and the effect of improving the moving image quality can be obtained.

Next, the input gradation is sufficiently large, the input gradation is 72.97% or more, that is, the display brightness is 50%.
When an image in which the above object moves on a background having a higher luminance than that of the object is input, each of the general hold-type display device and the display device (image display device) according to the first embodiment is selected. Explain how it looks.

  FIG. 56 is a diagram showing a state of luminance change with time on one horizontal line on the screen when a video as described above is input in a general hold type display device. In FIG. 56, as in FIG. 48, the entire one frame period T101 is the image lighting period T102, and there is no first or second half subframe period. FIG. 57 shows what kind of brightness distribution is seen by an observer who gazes at a moving object when an image is displayed as shown in FIG.

On the other hand, FIG. 58 is a diagram showing how the luminance changes with time on one horizontal line on the screen when the video as described above is input in the image display apparatus of the first embodiment.

As shown in FIG. 58, two subframe periods T201 and T202 are provided in one frame period T101, and each corresponds to the first half subframe period T201 and the second half subframe period T202. The input gradation of the moving object and the stationary background are 72.
Since it exceeds 97%, the second half subframe (A2) of the moving object and the second half subframe (B2) of the stationary background are both displayed with the maximum luminance, and the first half subframe (A1) of the moving object and the stationary background Different luminances are displayed in the first half subframe (B1). When the image is displayed as shown in FIG. 58, the distribution of brightness that is seen by an observer watching the moving object is shown in FIG. 59. The general hold-type display device shown in FIG. It can be seen that motion blur is improved compared to the case. As described above, the first embodiment has the effect of improving the moving image quality by the operation principle different from the black insertion method.

  In the first embodiment, as in the case of the image display device proposed in the seventh embodiment of Patent Document 1 shown in FIGS. 52 and 53, an image in which an object moves horizontally on a stationary background is displayed. With respect to the display brightness in this case, FIG. 10 shows how the brightness changes over time on one horizontal line in the screen.

  In FIG. 10, the horizontal axis represents the state of luminance in the horizontal direction on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  In the image display apparatus according to the first embodiment shown in FIG. 10, two subframe periods T201 and T202 are provided in one frame period T101, and the input image signal to be input is displayed on the stationary background display unit B. Therefore, 0% is supplied as the minimum level during the first subframe period T201 and is turned off, and the gradation level that is increased or decreased according to the gradation level of the input image signal in the second subframe period T202. Is supplied and is lit at a luminance of 40%. On the other hand, in the moving object display unit A, the gradation level of the input image signal is sufficiently larger than a predetermined threshold value, and therefore the level that is increased or decreased according to the gradation level of the input image signal in the first subframe period T201. The gray level is supplied and the light is turned on at a luminance of 20%. In the latter half subframe period T202, 100% is supplied as the maximum level and the light is turned on at a luminance of 100%. The number in the area indicating the display state of the image indicates the luminance when the maximum display luminance capacity is 100%. For example, B1 surrounded by a dotted line indicates luminance of 0%.

  FIG. 11 shows how the brightness distribution looks for an observer who is gazing at a moving object when an image as shown in FIG. 10 is displayed.

  In FIG. 11, there is a phenomenon that the broken line of the luminance change is different between the left end and the right end of the moving object. However, such a problem that a portion where the luminance is higher or smaller than the original as shown in FIG. 53 is improved.

  Next, the temperature correction function in the image display apparatus according to the first embodiment will be described.

  In the image display device according to the first embodiment, a liquid crystal display element is used as the display element 11 a of the display panel 10. It is known that the response speed of a liquid crystal material is generally slow at low temperatures and fast at high temperatures. In addition, depending on the temperature condition, there may be a difference in response speed between when the transmittance increases and when it decreases according to the change in gradation level. The degree of such a difference in response speed and the problem of which response speed is slower when the transmittance increases or decreases depend on the use conditions of the liquid crystal material.

In the first embodiment, the response speed when the transmittance increases and when the transmittance decreases is almost the same when the temperature is high, and the response speed at which the transmittance decreases as the temperature decreases is a liquid crystal. A display element is used. In the case where such a liquid crystal display element is used, in the image display apparatus that displays an image for one frame period by time integration of display luminances of two subframe periods as in the first embodiment, the same. Even if a gradation level image signal is supplied, the luminance may change depending on the temperature condition.

  FIG. 12 is a diagram showing a difference in display luminance depending on the temperature condition when the gradation level of the image signal supplied to the display panel 10 used in Embodiment 1 is not adjusted according to the temperature condition. The left side shows the liquid crystal response under high temperature, and the right side shows the liquid crystal response under low temperature. The thick line indicates the gradation level, and the same level is supplied at high and low temperatures. Further, the gray (hatched) region shows the luminance that varies depending on the liquid crystal response.

  As described above, the liquid crystal display element used in the first embodiment is a liquid crystal display element in which the response speed is lowered when the transmittance is lowered (luminance is lowered) as the temperature is lowered. Therefore, at the low temperature shown on the right side of FIG. 12, the luminance is not sufficiently lowered in the first half subframe period as compared with the high temperature shown on the left side, and as a result, the luminance integrated over time is increased. For this reason, even if image signals having the same gradation level are supplied at high temperatures and low temperatures, the brightness perceived by human eyes will be different. It is not preferable for the image display device 1 that the perceived brightness differs depending on the temperature condition for input image signals having the same gradation level. In order to solve such a problem, the image display apparatus 1 according to the first embodiment is provided with a temperature correction function for the output image signal.

  Specifically, the temperature level signal output from the temperature sensor IC 20 installed in the vicinity of the display panel 10 is input to the first gradation conversion circuit 44 and the second gradation conversion circuit 45 in the controller LSI 40. ing. As described above, the first gradation conversion circuit 44 and the second gradation conversion circuit 45 are configured by a lookup table that converts an input gradation level to an output gradation level. A lookup table used for gradation conversion is switched in accordance with a temperature level signal from the temperature sensor IC 20.

  FIG. 13 is a diagram showing the display brightness when the output gradation level is changed due to the difference in temperature condition for the display panel 10 used in the first exemplary embodiment. The left side of FIG. 13 shows the state of the liquid crystal response under high temperature, and the right side shows the state of the liquid crystal response under low temperature. A thick line indicates a change in gradation level, and a gray (hatched) region indicates a luminance that changes depending on a liquid crystal response.

  With the above-described temperature correction function, a lower gradation level is supplied at a low temperature shown on the right side of FIG. 13 than in the case of a high temperature shown on the left side of FIG. The luminance change due to the response delay is set to be equivalent to that at a high temperature. Thus, the brightness perceived by humans when the gradation levels of the input image signals are the same can be made equal regardless of the temperature condition.

As described above, according to the image display apparatus 1 of Embodiment 1, without reducing the maximum value of the time integral of a brightness luminance eyes of the viewer feel, original upon watching a moving object It is possible to reduce motion blur and improve the moving image quality of the hold-type image display device without generating abnormal bright and dark portions as compared with images. In addition, an image can be displayed by gradation expression having an appropriate luminance gamma characteristic with respect to the input image signal. Furthermore, even when the liquid crystal panel 10 is used, the relationship between the input image signal and the brightness perceived by the observer can be kept constant regardless of the temperature condition.

(Embodiment 2)
The second embodiment is an image display device that displays an image for one frame period based on the total amount of time integration of luminance displayed in two subframe periods, and displays the image display unit for each frame period. Comprising display control means for performing image display control of the two subframe periods;
One subframe period is a subframe α period, and the other subframe is a subframe β period. Two gradation level threshold values T1 and T2 are determined, and the threshold value T2 is larger than the threshold value T1. When the gradation level of the image signal to be output is equal to or less than the threshold value T1, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit in the subframe α period. In the subframe β period, the image signal having the minimum gradation level is supplied to the image display unit. When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the subframe α In the period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in the subframe β period, the subframe α period The gradation level of the input image signal is supplied to the image display unit by supplying an image signal of a gradation level that is smaller than the gradation level to be supplied and is increased or decreased according to the gradation level of the input image signal. Is larger than the threshold value T2, the image signal having the maximum gradation level is supplied to the image display unit during the subframe α period, and the gradation that is increased or decreased according to the input image signal during the subframe β period. An image display apparatus that supplies level image signals to the image display unit will be described.

  In the first embodiment, the assumed luminance of the input image signal is shown in FIG. 15 for changes in display luminance when displaying an image in which an image that changes stepwise as shown in FIG. 14 moves in the horizontal direction. It shows. In the first embodiment, the luminance of the first half sub-frame (T201) is fixed to 0% until the assumed luminance of the input image signal exceeds 50%, and when the luminance exceeds 50%, the luminance of the first subframe (T201) depends on the assumed luminance of the input image signal. To increase. Further, the luminance of the latter half subframe (T202) increases according to the luminance assumed for the input image signal until the luminance assumed for the input image signal reaches 50%, and is fixed to 100% when it exceeds 50%. FIG. 16 shows how the luminance distribution can be seen by the observer's eyes when such display is performed. Discontinuity points (○ in the figure) appear in the middle of the luminance change that should have changed gently. The part surrounded by) appears. Such a discontinuous point may be seen by an observer as an abnormal image such as a pseudo contour.

  In the second embodiment, the gradation distribution method for the first half and second half subframes is changed in order to suppress the occurrence of such a problem. The setting target of the display brightness value in the second embodiment is shown in FIG.

  In the second embodiment, the gradation value when the luminance assumed as the gradation level threshold T1 is 25% and the gradation value when the luminance assumed as the gradation level threshold T2 is 75% are determined. When the assumed luminance level of the input image signal is a threshold value T1, that is, 25% or less, the luminance level is “0” in the first half subframe that is subframe β and the input image signal is in the second half subframe that is subframe α. Is displayed at a luminance level that changes according to the assumed luminance level.

In addition, when the assumed luminance level of the input image signal is larger than the threshold T1, that is, 25% and is lower than the threshold T2, that is, 75% or less, the luminance level ranges from 0% to 50% in the first half subframe which is the subframe β. Thus, in the second half sub-frame which is sub-frame α, the luminance level in sub-frame α and the luminance in sub-frame β are each in the range of luminance levels from 50% to 100% according to the assumed luminance level of the input image signal. The brightness level is maintained so that the level difference is maintained at 50%. At this time, regarding the relationship between the subframe α and the subframe β, the difference between the luminance level or the supplied gradation level may be constant, or the ratio may be constant. Alternatively, the luminance level of the subframe α and the subframe β or the gradation level to be supplied may be defined by some function.

  Furthermore, when the luminance level assumed as the input image signal is larger than the threshold value T2, that is, the luminance value of 75%, the luminance that changes in accordance with the luminance level assumed as the input image signal in the first half subframe that is subframe β. In the latter half subframe, which is subframe α, the display is at a luminance level of 100%.

  Compared to the first embodiment, the target display luminance in the first subframe and the second subframe in the range where the luminance assumed by the input image signal is 25% or more and less than 75% is as in the first embodiment. Unlike in the case of increasing sequentially from the second half subframe to the first half subframe, the second embodiment increases both the second half subframe and the first half subframe. In the case where the luminance assumed by the input image signal is in the ranges of 25% or less and 75% or more, the first embodiment and the second embodiment are the same.

  As an example, FIG. 17 shows a target setting example of the display luminance value in the second embodiment. Comparing this with FIG. 8 showing a target setting example of the display luminance value of the first embodiment, when the luminance assumed by the input image signal is, for example, 50%, each display luminance in the first half subframe and the second half subframe Is different. Unlike the case where the target display luminance is increased to 100% in the second half subframe and then increased from 0% in the first half subframe as in the first embodiment, in the second embodiment, the second half subframe is increased. While the frame is increased from 50% to 100%, the first subframe is increased from 0% to 50%.

  Next, in the range in which the luminance assumed by the input image signal in the second embodiment is 25% or more and less than 75%, the gradation supplied in each subframe in order to maintain the target display luminance as described above. Explain the level.

Also in the second embodiment, the display panel has a gamma luminance characteristic as in the first embodiment, and the input image signal also has a gamma luminance characteristic assuming a CRT. As described above, when the difference between the luminance level in the first subframe and the luminance level in the second subframe is maintained at 50%, the relationship between the gradation levels of the first subframe and the second subframe is as follows. It is expressed by the following formula.
(Second half gradation / maximum gradation) ^γ− (first half gradation / maximum gradation) ^γ = 0.5
(Γ = 2.2) (Formula 3)
The relational expression for the input gradation is the same as (Expression 2) described in the first embodiment. From these relational expressions, FIG. 18 shows the relationship between the gradation level of the input image signal, the gradation level supplied in the first half and the second half subframe, and the time integral value of the actually displayed luminance in the second embodiment. Show. Compared to the case of FIG. 9 showing the relationship between the gradation level of the input image signal in the first embodiment, the gradation level supplied in the first half and the second half subframe, and the time integral value of the actually displayed luminance, It can be seen that when the time integration value is 50%, the difference between the gradation level supplied in the first half subframe and the gradation level supplied in the second half subframe is small.

  Furthermore, in the second embodiment, the display luminance when an image in which the luminance assumed by the input image signal as shown in FIG. 14 changes stepwise is displayed in the horizontal direction. The change is shown in FIG. At this time, the display luminance level in the first half subframe (T201) and the second half subframe (T202) is B2 where the assumed luminance level of the input image signal is 40% and B3 where the assumed luminance level is 60%. Unlike FIG. 15 of the first embodiment, it can be seen that the difference between the first half subframe luminance and the second half subframe luminance is 50%.

  Furthermore, when such a display is performed, how the luminance distribution is seen by the observer's eyes is shown in FIG. 20, the discontinuity point of the luminance change that appeared in FIG. 16 of the first embodiment. It can be seen that the (circled portion) is improved like the circled portion (the state where there is no discontinuous point) in FIG.

  As described above, according to the image display device of the second embodiment, in addition to the same effect as that of the first embodiment, an image whose luminance assumed by the input image signal is changed stepwise is moved. Even when a simple image is displayed, it is possible to avoid a phenomenon in which a discontinuity point in luminance change is seen by an observer.

(Embodiment 3)
The third embodiment is an image display device that displays an image for one frame period based on the total amount of time integration of luminance displayed in two subframe periods. The image display unit is displayed for each frame period. Display control means for performing image display control in two subframe periods, one subframe period being a subframe α period and the other subframe being a subframe β period, and threshold values T1 and T2 of two gradation values And the threshold value T2 is larger than the threshold value T1, the gradation level L is uniquely determined, and when the gradation level of the input image signal is equal to or less than the threshold value T1, In the frame α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in the subframe β period, the minimum gradation is supplied. In the case where the image signal of the bell is supplied to the image display unit and the gradation level of the input image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the gradation level L is set to be lower in the subframe α period. In the subframe β period, an image signal having a gradation level that is increased or decreased according to the input image signal is supplied to the image display unit, and the gradation level of the input image signal is greater than the threshold value T2. In this case, in the subframe α period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and in the subframe β period, the maximum level is supplied. An image display apparatus that supplies a tone level image signal to the image display unit will be described.

  In the third embodiment, since the magnitude relationship between the luminances of the subframe α and the subframe β differs depending on the gradation level of the input image signal, which subframe is assigned to the first half and the second half subframe is described above. Although not determined by the relationship between the response time when switching from the minimum luminance level to the maximum luminance level and the response time when switching from the maximum luminance level to the minimum luminance level as in the first mode, other displays It is desirable to decide according to the characteristics of the panel and the characteristics of the displayed image. Here, a case where subframe β is assigned to the first half subframe and subframe α is assigned to the second half subframe will be described.

  The setting target of the display brightness value in the third embodiment is shown in FIG. 21, for example.

  In the third embodiment, as shown in FIG. 21, the gradation value when the luminance assumed as the threshold T1 of the gradation level is 25% and the gradation level when the luminance assumed as the threshold T2 is 75% And a gradation level when the luminance value assuming a predetermined gradation level L is 50%. When the assumed luminance level of the input image signal is the threshold value T1, that is, 25% or less, the luminance of the latter half subframe that is subframe α changes according to the input image signal, and the first half subframe that is subframe β. The luminance of the frame is fixed at 0% (minimum value).

  Further, when the assumed luminance level of the input image signal is larger than the threshold T1, that is, 25%, and the threshold T2, that is, 75% or less, the luminance of the second subframe which is the subframe α is the gradation level L, that is, 50. The luminance of the first subframe, which is subframe β, is fixed in accordance with the input image signal.

  Further, when the assumed luminance level of the input image signal is larger than the threshold value T2, that is, 75%, the luminance of the latter half subframe, which is subframe α, changes according to the input image signal and is subframe β. The luminance of the first half subframe is fixed at 100% (maximum value).

  Here, in order to realize the display luminance target as described above in the third embodiment, the gradation levels of the image signals supplied to the first half and second half subframes are shown in FIG.

  In the third embodiment, the display panel having the gamma luminance characteristic represented by (Equation 1) is used as in the case of the first embodiment, and the input image signal is also represented by (Equation 1). This is an image signal assuming a gamma luminance characteristic.

  In the third embodiment, as in the case of the image display device proposed in the conventional patent document 1 (seventh embodiment) shown in FIGS. 52 and 53, an image in which an object moves horizontally on a stationary background. FIG. 23 shows how the luminance changes as time elapses on one horizontal line in the screen with respect to the display luminance when displaying. In the portion B, which is a stationary background image, the same luminance display as in the first embodiment shown in FIG. 10 is shown, but in the portion A, which shows a moving object, the luminance level assumed by the input image signal is Since it exceeds 50%, the luminance level in the latter half subframe (T202) is larger than the luminance level in the first half subframe (T201).

  FIG. 24 shows what brightness distribution is seen by an observer who is gazing at a moving object when an image as shown in FIG. 23 is displayed. In FIG. 24, there is a phenomenon in which the broken line of the luminance change is different between the left and right circle portions of the moving object. However, as in the case of the first embodiment, a place where the luminance is higher or lower than originally shown in FIG. The problem that a part occurs is improved.

(Embodiment 4)
The image display apparatus according to the fourth embodiment is different from the image display apparatus according to the first embodiment in the response characteristics of the display panel used. In addition, an upper limit value of the supplied gradation level is provided for one of the subframes, thereby improving the moving image blurring improvement effect.

  Unlike the first embodiment, the display panel used in the fourth embodiment has a long response time when switching from the maximum luminance level to the minimum luminance level, and the response is insufficient in one subframe period. The response time for switching from the minimum luminance level to the maximum luminance level is short, and the display panel has a luminance response characteristic such that the luminance response is almost completed in one subframe period. Therefore, contrary to the case of the first embodiment, the subframe α is assigned to the first half subframe, and the subframe β is assigned to the second half subframe.

  In the fourth embodiment, luminance values that are set targets in the first half subframe and the second half subframe will be described.

  FIG. 25 is a diagram illustrating target setting of display luminance values in the fourth embodiment.

In FIG. 25, the left column shows the assumed luminance value of the input image signal, and the center column shows the display luminance in the first subframe period and the second subframe period in the fourth embodiment. The right column shows values obtained by time-integrating the luminance values of two subframe periods in one input frame period. This is considered to correspond to the brightness that is actually perceived by the observer's eyes, but here, the maximum capability value obtained by time-integrating the luminance in the display panel 10 is 100%. From the upper part of FIG. 25, the luminance values assumed as input image signals are 0%, 25%, 50%, 66.67%, 75%, and 100%, respectively.

As shown in FIG. 25, the assumed luminance of the input image signal is 2/3 (66.67%) of the maximum luminance as a threshold for determining the gradation level of the image signal supplied in each subframe period. The case is set. When the assumed luminance of the input image signal is 2/3 (66.67%) or less of the maximum luminance, the luminance of the first subframe period is
[Luminance in the first half subframe period]
= [Assumed luminance of input image signal] × 1.5
(Predetermined ratio; multiplication value 1.5) is increased or decreased according to the assumed luminance of the input image signal. For example, when the assumed luminance of the input image signal is 25% of the maximum luminance, the luminance in the first half subframe period is 25% × 1.5 = 37.5%.

  When the assumed luminance of the input image signal is larger than 2/3 (66.67%) of the maximum luminance, the luminance in the first half subframe period is set to the maximum luminance (100%). The threshold value of 2/3 (66.67%) becomes 100% when multiplied by 1.5.

  On the other hand, the luminance of the second subframe is set to the minimum luminance (0%) when the assumed luminance of the input image signal is 2/3 (66.67%) or less of the maximum luminance.

When the assumed luminance of the input image signal is larger than 2/3 (66.67%) of the maximum luminance,
[Luminance in the second half subframe period]
= ([Assumed luminance of input image signal] −2/3) × 1.5
(Predetermined ratio; multiplication value 1.5) is increased or decreased according to the assumed luminance of the input image signal. For example, when the assumed luminance of the input image signal is 75% of the maximum luminance = 3/4, the luminance in the latter subframe period is (3 / 4−2 / 3) × 1.5 = 1/8 = 12.5%.

  In the fourth embodiment, in order to improve the moving image quality, the upper limit value L1 of the gradation level of the image signal supplied in the first subframe period and the gradation level of the image signal supplied in the second subframe period are set. The upper limit value L2 is set so as to satisfy the relationship L1 ≧ L2. In this example, the upper limit of the luminance in the first half subframe period is 100%, and the upper limit of the luminance in the second half subframe period is 50%.

  As described above, since the luminance in the second subframe period is set to 50%, the maximum brightness perceived by the observer's eyes is reduced by 25%. However, even when the assumed luminance value of the input image signal is maximum (100%), motion blur is reduced because there is a luminance difference between the first half subframe period and the second half subframe period.

  The assumed brightness of the display panel and the input image signal in the fourth embodiment has the same γ brightness characteristics as in the first embodiment, and follows the relationship (Equation 1) between the input image signal and the display brightness.

  In the fourth embodiment, each subframe is set so that the relationship between the gradation level of the input image signal to be input and the temporal integration amount of the display luminance in one frame period shows an appropriate gamma luminance characteristic in still image display. A threshold value that is a criterion for determining the gradation level of the image signal in the period and a gradation level of the image signal that is increased or decreased according to the input image signal and supplied in each subframe period are set.

In the fourth embodiment, the time integral of the display luminance in the first and second subframe periods is considered as the brightness perceived by the observer. In particular, in the fourth embodiment, the gradation level of the input image signal is considered. The luminance value in the latter half subframe period is limited to half or less of the maximum capacity of the display panel 10 so that the motion blur can be reduced even when the brightness is large. Therefore, hereinafter, a luminance value that is 75% of the maximum capability value of the display panel 10 in terms of time integration of luminance in one frame period will be described as the maximum luminance that can be expressed by the image display device 1.

  In this case, the relationship between the gradation level of the input image signal, the gradation level supplied in the first half subframe period, and the gradation level supplied in the second half subframe period is expressed by the following equation. The

(Input gradation / maximum gradation) ^γ
= {(First half gradation / maximum gradation) ^γ + (second half gradation / maximum gradation) ^γ } / 2
× (1 / 0.75)
(Γ = 2.2) (Formula 4)
FIG. 26 is a diagram showing the relationship between the gradation level of the input image signal satisfying the relationship of Equation 2 above and the gradation level supplied in the first half and second half subframe periods.

  In FIG. 26, the left column indicates the gradation level of the input image signal to be input, and the center column converts the gradation level of the input image signal and is supplied in the first and second subframe periods. Indicates the key level. Further, as a result, the right column shows luminance obtained by time integration in one frame period. From the upper part of FIG. 26, the gradation levels of the input image signal to be input are 0%, 25%, and 50%, respectively. , 75%, 83.2% and 100%.

  As shown in FIG. 26, a case where the assumed luminance of the input image signal is 83.2% of the maximum luminance is set as a threshold for determining the gradation level of the image signal supplied in each subframe period. Yes. When the assumed luminance of the input image signal is 83.2% or less of the maximum luminance, the gradation level of the image signal supplied in the first half subframe period satisfies the relationship shown in Equation 2 above, and the input image signal It is increased or decreased according to the assumed brightness. Further, the gradation level of the image signal supplied in the other subframe period is set to the minimum level 0 (%).

  On the other hand, when the assumed luminance of the input image signal is 83.2% or more of the maximum luminance, the gradation level of the image signal supplied in the first half subframe period is set to the maximum level (100%), and the latter half The gradation level of the image signal supplied during the sub-frame period satisfies the relationship expressed by the above equation 2 and is increased or decreased according to the assumed luminance of the input image signal.

  Here, the gradation level of the image signal supplied in the first half subframe period is output from the line buffer 41 in which the input image signal is temporarily stored, and is converted by the first gradation conversion circuit 44 in the control LSI 40. Value. Further, the gradation level of the image signal supplied in the latter half subframe period is read from the frame memory 30 in which the input image signal is temporarily stored and converted by the second gradation conversion circuit 45 in the control LSI 40. Value.

  When the converted gradation level is supplied as shown in the center column of FIG. 26, the source driver of the display panel 10 has the above-described formula 1 and FIG. 54 in each of the first and second subframe periods. An image is displayed with a luminance according to the gamma luminance characteristics.

As a result, as the brightness perceived by the observer's eyes, the value obtained by time-integrating the display luminance in the first and second subframe periods in one frame period is shown in the right column of FIG. The luminance value time-integrated in one frame period reproduces the gamma luminance characteristic assumed by the input image signal as shown in the above equation 1 and FIG. 54 with respect to the gradation level of the input image signal. ing. Thereby, it can be seen that an appropriate gamma characteristic is realized by the image display device and the image display method of the fourth embodiment.

  In addition, in the image display apparatus according to the fourth embodiment in which image display is performed by the image display method as described above, an input image that is input when an image in which an object moves in a horizontal direction on a stationary background is displayed. When the gradation level of the signal is sufficiently small, the minimum gradation level is supplied in the second subframe period in any of the stationary background display section and the moving object display section. Similar to the black insertion type image display device shown in FIGS. 50 and 51, it is possible to obtain the effect of improving the moving image quality such as reduction of motion blur and improvement of contrast.

  Further, in the fourth embodiment, as in the case of the image display device proposed in the conventional patent document 1 (seventh embodiment) shown in FIGS. 52 and 53, the object moves horizontally on the stationary background. FIG. 27 shows how the luminance changes with time on one horizontal line in the screen with respect to the display luminance when a simple video is displayed.

  In FIG. 27, the horizontal axis represents the state of luminance in the horizontal direction on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  In the image display apparatus according to the fourth embodiment shown in FIG. 27, two subframe periods T201 and T202 are provided in one frame period T101. In the stationary background display unit B, the input image signal to be input is displayed. Since the gradation level is small, a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied in the first half subframe period T201 and is lit at a luminance of 40%, and the minimum level is displayed in the second half subframe period T202. Is supplied and 0% is turned off. On the other hand, in the moving object display portion A, the gradation level of the input image signal is sufficiently larger than a predetermined threshold value, so that 100% is supplied as the maximum level in the first subframe period T201 and the light is turned on at a luminance of 100%. In the latter half subframe period T202, a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and the light is lit at a luminance of 20%. The number in the area indicating the display state of the image indicates the luminance when the maximum display luminance capacity is 100%. For example, B1 surrounded by a dotted line indicates the luminance of 40%.

  FIG. 28 shows how the brightness distribution looks for an observer who is gazing at a moving object when an image as shown in FIG. 27 is displayed.

  In FIG. 28, there is a phenomenon that the broken line (circled portion) of the luminance change is different between the left end and the right end of the moving object, but the problem that the portion where the luminance is higher or smaller than the original as shown in FIG. 53 is improved. ing.

  FIG. 30 is a diagram showing display luminance when the output gradation level is changed due to a difference in temperature condition for the display panel 10 used in the fourth exemplary embodiment. The left side of FIG. 30 shows the state of the liquid crystal response at a high temperature, and the right side shows the state of the liquid crystal response at a low temperature. A thick line indicates a change in gradation level, and a gray (hatched) region indicates a luminance that changes depending on a liquid crystal response.

  With the above-described temperature correction function, a low gradation level is supplied at a low temperature shown on the right side of FIG. 30, particularly in the latter half of the subframe period, compared to a case of a high temperature shown on the left side of FIG. The luminance change due to the delay in the liquid crystal response is made to be equivalent to that at a high temperature. Thus, the brightness perceived by humans when the gradation levels of the input image signals are the same can be made equal regardless of the temperature condition.

As described above, according to the image display device 1 of the fourth embodiment, when a moving object is watched while suppressing a decrease in the maximum value in luminance time integration, which is the brightness perceived by the observer's eyes, to 25%. In addition, motion blur can be reduced and the moving image quality of the hold-type image display device can be improved without generating abnormal bright and dark portions as compared with the original image. In addition, an image can be displayed by gradation expression having an appropriate luminance gamma characteristic with respect to the input image signal.

(Embodiment 5)
In the fifth embodiment, an image display apparatus in which color expression is performed by supplying gradation levels independently to each of the three primary colors red, green, and blue will be described.

  FIG. 31 shows a case where red, green, and blue primary colors are displayed with independent luminance in the image display device according to the first embodiment, and a red background is displayed on a stationary background in which all colors have a luminance of 0%. In the case of displaying an image in which an object having a color such that the luminance level assumed by the input image signal is 75% and the luminance level assumed by the green and blue input image signals is 50% is displayed on one horizontal line It is a figure which shows the display state for every time passage in each pixel part.

  31, in this image display device, as shown in FIG. 8, for each of the red, green and blue color components, the luminance level assumed by the input image signal and the luminance levels in the first and second subframe periods are shown. Follow the relationship. For this reason, regarding the moving object display portion A, only red is displayed with a luminance of 50% in the first half subframe period, and all colors are displayed with a luminance of 100% in the second half subframe period.

  Paying attention to the diagonal arrow (dotted line) that shows the tracking path of the observer's gaze following the moving object, the observer sees the appropriate color at the center of the object as when stationary, but at the right end of the object It can be seen that, on the contrary, red appears to be insufficient at the left end. In this way, the balance of the luminance of the three colors is lost, so that an abnormal color can be seen.

  This is because the red input image signal has a large gradation level and is displayed over two subframe periods of the first half and the second half, whereas the gradation levels of the other two color input image signals are small, and the first half. This is because the display is turned on only in the subframe period, and the temporal center-of-gravity position of display lighting differs between red and the other two colors.

  In order to avoid such a phenomenon, in the fifth embodiment, in the image display device 1 in which image display of one frame period is performed by two subframe periods of the first half and the second half, the color component having the largest input gradation level For the other color components, the gradation level control method supplied in the first subframe period and the second subframe period is improved.

  Specifically, among the three colors described above, for the color having the highest gradation level of the input image signal, the maximum gradation level or the input floor in the second half subframe period, as in the first embodiment. A gradation level that is increased or decreased according to the tone is supplied, and a gradation level that is increased or decreased according to the input gradation is supplied during the first half subframe period. The ratio of the luminance displayed in the first half subframe period and the luminance displayed in the second half subframe for two colors other than the color having the highest gradation level of the input image signal is the first half for the color having the highest input gradation level. The gradation level is set and supplied to each subframe period so as to have the same ratio as the ratio of the luminance displayed in the subframe period and the luminance displayed in the second half subframe period.

  In the fifth embodiment, the temporal flow of the image signal and the driving method of the display panel 10 are the same as those in the first embodiment, and a description thereof is omitted here. Hereinafter, as a difference from the first embodiment, a gradation conversion method in the first gradation conversion circuit 44 and the second gradation conversion circuit 45 for two colors other than the color having the largest input gradation will be described. .

The display panel 10 used in the fifth embodiment is similar to the first embodiment described above.
[Display luminance] = ([Image signal gradation] / [Maximum gradation]) ^γ (γ = 2.2)
(However, the maximum display brightness is 1 and the minimum is 0)
It has a gamma characteristic as follows.

First, for a color component having the largest input gradation level in a certain pixel of a certain input frame, the ratio between the gradation level supplied in the first half and the second half subframe period and the maximum gradation level is set to X ₁ and and X _2.

X ₁ = [first half subframe gradation level] / [maximum gradation level]
X ₂ = [second half subframe gradation level] / [maximum gradation level]
At this time, the display brightness in each subframe period is based on the above-described gamma characteristics.
[Display brightness of first subframe] = X ₁ ^γ
[Display luminance of the second half subframe] = X ₂ ^γ
It becomes.

Similarly, with respect to a certain color component other than the color component having the largest input gradation level, the ratio between the gradation level supplied in the first half and the second half subframe period and the maximum gradation level is set to Y ₁ and Y ₂ , respectively. And

Y ₁ = [first half subframe gradation level] / [maximum gradation level]
Y ₂ = [second half subframe gradation level] / [maximum gradation level]
At this time, the display brightness in each subframe period is based on the above-described gamma characteristics.
[Display luminance of first half subframe] = Y ₁ ^γ
[Display luminance of the second half subframe] = Y ₂ ^γ
It becomes.

In the fifth embodiment, with respect to a certain color component other than the color component having the largest input gradation level, the luminance ratio displayed in the first half and the second half subframe period is the color component having the largest input gradation level. Since it matches the luminance ratio displayed in the first and second subframe periods,
Y ₁ ^γ : Y ₂ ^γ = X ₁ ^γ : X ₂ ^γ (Formula 5)
It becomes the relationship.

Assuming that the tone level of the input image signal is Y for a color component other than the color component having the largest input tone level, as described in the fourth embodiment, the tone level of the input image signal and one frame are set. In order to make the relationship with the time integral value of luminance in the period appropriate gamma characteristics,
Y ^γ = (Y ₁ ^γ + Y ₂ ^γ ) / 2 (Expression 6)
It is necessary to satisfy the relationship.

From Equation 3 and Equation 4 above,
Y ₁ = Y · {2X ₁ ^γ / (X ₁ ^γ + X ₂ ^γ )} ^{1 / γ} (Expression 7)
Y ₂ = Y · {2X ₂ ^γ / (X ₁ ^γ + X ₂ ^γ )} ^{1 / γ} (Expression 8)
It becomes.

  Therefore, with respect to the gradation level of a certain color component other than the color component having the largest input gradation level, the above expression 5 and expression 6 are used in the first gradation conversion circuit 44 and the second gradation conversion circuit 45 in the controller LSI 40. The output gradation level is determined by performing an operation in accordance with the above.

In the image display apparatus according to the fifth embodiment, as in the case of FIG. 31, the input image signal is assumed to have a luminance level assumed to be 75% and a green and blue input image signal on a background where all colors have a luminance of 0%. FIG. 32 shows the luminance change of each pixel portion on one horizontal line over time when an image in which an object of a color whose luminance level is 50% moves horizontally is displayed.

  In FIG. 32, unlike the case of FIG. 31, even when attention is paid to one of the first and second subframe periods, the luminance ratio of each color of red, green, and blue is maintained appropriately. For this reason, for the observer watching the moving object, there is no problem that an abnormal color is seen because the balance of the luminance of the three colors is lost at both ends of the object.

(Embodiment 6)
In the sixth embodiment, the image display of one frame period is performed by the two subframe periods of the first half and the second half, and the image of the frame in the intermediate state with respect to the two frames of images input successively. When the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value in one uniquely determined subframe period (for example, the first half subframe period) Is supplied with an image signal of a gradation level that is increased or decreased according to the gradation level of the input image signal, and when the gradation level of the input image signal is greater than a threshold value, the maximum gradation level is When the image signal is supplied and the gradation level of the image signal in the intermediate frame image is equal to or lower than the threshold in the other subframe period (for example, the second half subframe period) When an image signal with a small gradation level is supplied and the gradation level in the intermediate frame image is larger than the threshold value, the image signal is increased or decreased according to the gradation level of the image signal in the intermediate frame image. A case where an image signal is displayed by supplying an image signal of a gradation level will be described.

  FIG. 33 is a block diagram showing a main configuration of the sixth embodiment in the controller LSI 40 of FIG.

  As shown in FIG. 33, the controller LSI 40B as display control means of the sixth embodiment includes a single line buffer 41a as line data storage means, a timing controller 42 as timing control means, and frame storage data selection means. Frame memory data selector 43, first gradation conversion circuit 44 as first gradation conversion means, second gradation conversion circuit 45 as second gradation conversion means, and output data selector as output data selection means 46, a first multiline buffer 47 as a first multiline data storage means, a second multiline buffer 48 as a second multiline data storage means, a buffer data selector 49 as a temporary storage data selection means, An intermediate image generation circuit 50 as intermediate image generation means That.

  The single line buffer 41a receives and holds the inputted input image signal for each horizontal line. The single line buffer 41a includes a reception port and a transmission port independently, and can perform reception and transmission at the same time.

  The frame memory data selector 43 is controlled by the timing controller 42 and transfers the image signal held in the single line buffer 41a to the frame memory 30 by one horizontal line. Thereby, the input image signal is transferred to the frame memory 30 within one frame period. Since the frame memory 30 cannot perform transmission and reception at the same time, the timing controller 42 controls the switching of the frame memory data selector 43 (timing control) during a period that does not conflict with the data transfer to the frame memory 30. The image signal input one frame before and temporarily stored in the frame memory 30 is read out one horizontal line at a time and transferred to the first multi-line buffer 47. The image signal input to the frame memory 30 and read out from the frame memory 30 is read out one horizontal line at a time and transferred to the second multiline buffer 48.

  The intermediate image generation circuit 50 compares the image signals stored in the first multi-line buffer 47 and the second multi-line buffer 48, thereby comparing the previous frame image and the previous two frame images. An image signal of a frame that is intermediate in time is estimated and generated.

  The first multiline buffer 47 and the second multiline buffer 48 are buffer memories capable of holding image signals for several tens of horizontal lines. In the intermediate image generation circuit 50, the previous frame image is stored. The two previous frame images are compared in the range of the number of horizontal pixels × several tens of horizontal lines, and a temporally intermediate frame image is generated. For example, in the previous frame image, a partial area having the same shape that minimizes the sum of the differences in gradation levels with respect to the gradation level of each pixel portion in one partial area in the previous two frame images. And the partial area is estimated as the movement destination of one partial area in the previous two frame images. A method of obtaining an image of a frame in an intermediate state in terms of time by generating an image signal that is moved by a distance that is a half of the movement amount. In the sixth embodiment, a method for generating a frame image in an intermediate state in terms of time is not specified, and thus detailed description thereof is omitted here. In addition, in this way, when an image of a frame in an intermediate state is estimated and generated with respect to the input image signals of two frames, it is easy to generate an image that can be completely correctly interpolated. It is not considered. For this reason, it is possible that some of the pixel portions cause an incorrect display due to an interpolation error.

  The image signals generated by the intermediate image generation circuit 50 in this way are sequentially transferred to the second gradation conversion circuit 45.

  On the other hand, the image signal of the previous frame period held in the first multiline buffer 47 and the image signal of the previous frame period held in the second multiline buffer 48 are respectively stored in the buffer data selector 49. Also forwarded.

  The buffer data selector 49 is controlled by the timing controller 42, and the image signal of the previous frame period supplied from the first multiline buffer 47 and the two previous frame periods supplied from the second multiline buffer 48. Are switched alternately according to the display timing and transferred to the first gradation conversion circuit 44.

  In the first gradation conversion circuit 44, the gradation level of the image signal supplied from the buffer data selector 49 depends on the maximum gradation level or the gradation level of the input image signal as in the case of the fourth embodiment. Are converted into gradation levels that are increased or decreased.

  In the second gradation conversion circuit 45, the gradation level of the image signal supplied from the intermediate image generation circuit 50 is set to the minimum gradation level or the gradation level of the input image signal, as in the fourth embodiment. The gradation level is increased or decreased accordingly.

  The output data selector 46 is controlled by the timing controller 42 to select the image signal output from the first gradation conversion circuit 44 in the first half subframe period and output it as a panel image signal, and in the second half subframe period, the output data selector 46 The image signal output from the gradation conversion circuit 45 is selected and output as a panel image signal.

  The operation of the image display apparatus according to the sixth embodiment will be described with the above configuration.

  FIG. 34 is a diagram illustrating the flow of an image signal for each frame period in the image display apparatus according to the sixth embodiment.

  Each rectangle shown in FIG. 34 indicates the transfer period of the image signal for one frame. Further, characters such as N and N + 1 described in the rectangle indicate what frame of the image signal is transferred. Ci [f] described in the rectangle of the panel image signal indicates a signal obtained by converting the input image signal of the f-th frame by the i-th gradation conversion circuit 44 in the LSI. In addition, “.” In [] indicates an image of a frame in an intermediate state with respect to two frames. For example, C2 [N-1. N] indicates that a signal obtained by converting the image signal in the temporally intermediate state with respect to the input N−1th frame and the input Nth frame by the second gradation conversion circuit 45 is transferred.

  Regarding the frame memory 30, a gray rectangle (with hatching) indicates a signal writing period, and a white rectangle (without hatching) indicates a signal reading period. Since the frame memory 30 cannot read and write data at the same time, the actual writing and reading of data in the frame memory 30 are performed intermittently by dividing the periods indicated by the respective rectangles.

  As shown in FIG. 34, in the sixth embodiment, two subframe periods of the first half and the second half are provided in a period in which an image signal for one frame is input. In the first half subframe period, an image signal obtained by converting the image signal input in the previous two frame periods by the first gradation conversion circuit 44 is output. In the second half subframe period, the image signal is input in the two previous frame periods. An image signal obtained by converting the image signal of the temporally intermediate frame with respect to the received image signal and the image signal input in the previous frame period by the second gradation conversion circuit 45 is output.

  The driving method of the display panel 10 in the sixth embodiment is different from the first embodiment shown in FIGS. 3 and 4 in that image signals are sequentially transferred from the uppermost line of the screen to the lower line by one line. The general way to go.

  FIG. 35 is a diagram illustrating a state in which the image signal on the screen is rewritten in the image display device according to the sixth embodiment of the present invention. Here, a state is shown in which the image display is rewritten during the period in which the image signals of the Nth frame and the (N + 1) th frame are input.

  In addition, the diagonal arrow shown in FIG. 35 has shown the vertical position and rewriting timing in which the image rewriting of 1 line is performed. Ci [f] indicates that the image signal of the f-th frame is displayed by the image signal converted by the i-th gradation conversion circuit, and “.” In [] indicates the time of two frames. Fig. 5 shows an image of an intermediate frame, and the image display is held until the next image rewriting to the same line is performed. In FIG. 35, the position where the image display converted by the first gradation conversion circuit 44 is held is white (no hatching), and the position where the image display converted by the second gradation conversion circuit is held is gray. It is expressed as (with hatching). Dotted lines indicate the boundary positions of the four gate drivers to be driven.

  When attention is paid to the vertical position of one horizontal line on the screen, the display by the image signal obtained by converting the input image signal input two frames before by the first gradation conversion circuit 44 in the half period of the input one frame period. In the next half period, the second gradation conversion circuit 45 converts the image signal intermediate in time between the input image signal input two frames before and the input image signal input one frame before. It can be seen that display by the image signal is performed. Each half of the input one frame period is defined as a first half subframe period and a second half subframe period.

In the sixth embodiment, in the case where the display luminance of the stationary background and the moving object is the same as in the fourth embodiment shown in FIG. 27, the change in luminance over time on one horizontal line in the screen is illustrated. 36.

  In FIG. 36, the horizontal axis represents the state of luminance in the horizontal direction on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  As shown in FIG. 36, in the image display apparatus according to the sixth embodiment, two subframe periods T201 and T202 are provided in one frame period T101. In the stationary background display portion B, since the gradation level of the input image signal is small, the gradation that increases or decreases (increases or decreases by a predetermined ratio) according to the gradation level of the input image signal in the first subframe period T201. The level is supplied and turned on at a luminance of 40%, and 0% is supplied as the minimum level in the second subframe period T202 and the light is turned off. On the other hand, in the moving object display section A, the gradation level of the input image signal is sufficiently large, so that the maximum level is supplied as 100% in the first half subframe period T201, and the second half is turned on with a luminance of 100%. In the sub-frame period T202, a gradation level that is increased / decreased (increased / decreased by a predetermined ratio) according to the gradation level of the temporally intermediate frame image generated by the estimation is supplied and lit at a luminance of 20%. Yes. The number in the area indicating the display state of the image indicates the luminance when the maximum display luminance capacity is 100%. For example, B1 surrounded by a dotted line indicates the luminance of 40%.

  In addition, in the image displayed in the second subframe period, the image of the frame in the intermediate state with respect to the input image of the two frames serving as the source of the image of the first subframe period arranged before and after is used as the source. Therefore, the moving object is displayed at a position along the track of the line-of-sight tracking of the observer watching the moving object.

  FIG. 37 shows how the brightness distribution looks to the observer who has watched the moving object when the video as shown in FIG. 36 is displayed.

  As described above, in the display image in the latter half subframe period, the moving object display unit A is along the trajectory of the observer's line-of-sight tracking. It becomes easy to recognize the boundary with the moving object. Therefore, the width of motion blur is reduced compared to the case of the conventional general hold-type image display device shown in FIG. 49 and the case of the image display device of Embodiment 4 shown in FIG. . Further, unlike the image display device proposed in the conventional patent document 1 shown in FIG. 53, a portion having a higher or lower luminance than the original does not occur.

  Further, in the sixth embodiment, the temporally intermediate frame image signal is assigned to the latter subframe period converted to a relatively small gradation level, and the externally input image signal is relatively large. Occurs in some pixel units when the temporally intermediate frame image is estimated and generated from the image signal of two frames by assigning it to the first subframe period converted to the gradation level. It is possible to display an incorrect display due to an interpolation error that can be performed without conspicuous.

  Also in the sixth embodiment, similarly to the fourth embodiment, the upper limit L1 of the gradation level of the image signal supplied in one subframe period and the gradation of the image signal supplied in the other subframe period. The upper limit value L2 of the level can be set so as to satisfy the relationship of L1 ≧ L2. As a result, even when the assumed luminance of the input image signal is maximum, a predetermined or larger luminance difference is provided between the first half subframe period and the second half subframe period, so that motion blur can be reduced.

In the sixth embodiment, as in the fourth embodiment, the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period is an appropriate gamma luminance characteristic. As shown in the figure, a threshold value that is a criterion for determining the gradation level of the image signal in each subframe period, and a gradation level of the image signal that is increased / decreased according to the input image signal and supplied in each subframe period Can be set. As a result, an image can be displayed on the display element by gradation expression having an appropriate luminance gamma characteristic with respect to the input image signal.

  Further, in the sixth embodiment, as in the fourth embodiment, the gradation of the image signal in each subframe period in accordance with the temperature level signal from the temperature sensor IC 20 that detects the panel temperature or its surrounding temperature. It is possible to set a threshold value serving as a level determination criterion and a gradation level of an image signal that is increased / decreased (multiplied at a predetermined rate) according to an input image signal and supplied in each subframe period. Thereby, even when the liquid crystal panel 10 is used, the relationship between the input image signal and the brightness perceived by the observer's eyes can be kept constant regardless of the temperature condition.

  Further, in the sixth embodiment, as in the fifth embodiment, when the input image signal is composed of image signals of a plurality of color components, the gradation level of the input image signal is the highest. The ratio between the luminances displayed for each subframe period for color components other than the color components (for example, the luminance displayed in the first half subframe period of blue and green and the luminance displayed in the second subframe period) The ratio between the luminances displayed for each subframe period for the color component having the highest gradation level of the input image signal (the luminance displayed for the first subframe period of red) The gradation level of the image signal supplied in each subframe period can be set so that the ratio to the luminance displayed in the second subframe period is the same.Thereby, the ratio of the luminance of each color is maintained appropriately, and deterioration of image quality due to an incorrect color balance can be prevented.

(Embodiment 7)
In the seventh embodiment, image display for one frame period is performed based on the total amount of time integration of luminance displayed in two subframe periods, and one uniquely defined subframe period (for example, the first half subframe period). ), When the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied. When the gradation level of the input image signal is larger than the threshold value, the image signal of the maximum gradation level is supplied, and in the other subframe period (for example, the second half subframe period), the image signal of the current frame period If the average value of the gradation level of the image signal and the gradation level of the image signal in the previous or next frame period is less than or equal to the threshold value, the image signal having the minimum gradation level Is supplied, in which case the average value is greater than the threshold value, a case will be described in which the average value level gray level image signals that are increased or decreased according to the been supplied image display is performed.

  FIG. 38 is a block diagram showing a main configuration of the seventh embodiment in the controller LSI 40 of FIG.

  As shown in FIG. 38, the controller LSI 40C as the display control means of the seventh embodiment is a gradation level averaging circuit as a gradation level averaging means instead of the intermediate image generation circuit 50 in FIG. 33 (Embodiment 6). 51 is provided. The gradation level averaging circuit 51 adds the gradation levels of the two image signals stored in the first multiline buffer 47 and the second multiline buffer 48 and divides the two image signals by 2, thereby dividing the two image signals. An average value of the gradation levels is calculated and supplied to the second gradation conversion circuit 45.

  The controller LSI 40C according to the seventh embodiment operates in the same manner as in the sixth embodiment.

  The flow of the image signal for each frame period in the seventh embodiment is as shown in FIG. 34 as in the case of the sixth embodiment. This is the same as in the case of the sixth embodiment, but in the seventh embodiment, the difference is that “.” In [] indicates an image based on the average value of two frame image signals. .

  In the seventh embodiment, the state in which the image signal on the screen is rewritten is as shown in FIG. 35 as in the sixth embodiment. Also in this case, the difference is that “.” In [] indicates an image based on the average value of image signals in two frames.

  By such an operation, the controller LSI 40C outputs the image signal obtained by converting the previously input image signal by the first gradation conversion circuit 44 as the panel image signal in the first half subframe period, and the second half subframe. During the period, an image signal obtained by converting the average value of the image signals of two frames input in succession by the second gradation conversion circuit 25 is output as a panel image signal.

  In the seventh embodiment, in the case where the display luminance of the stationary background and the moving object is the same as that of the fourth embodiment shown in FIG. 27, the luminance change over time on one horizontal line in the screen is shown in FIG. It shows.

  In FIG. 39, the horizontal axis represents the state of luminance in the horizontal direction on the screen, and the vertical axis represents the passage of time, representing screen display for a three-frame period.

  In the image display apparatus according to the seventh embodiment shown in FIG. 39, two subframe periods T201 and T202 are provided in one frame period T101. In the stationary background display portion B, the gradation level of the input image signal and the gradation level of the average value of the image signals of two frames that are successively input are small, so that the input is performed in the first subframe period T201. A gradation level that is increased or decreased according to the gradation level of the image signal is supplied and turned on at a luminance of 40%, and 0% is supplied as the minimum level in the latter subframe period T202 and turned off. On the other hand, in the moving object display portion A, the gradation level of the input image signal and the gradation level of the average value of the image signals of two frames input in succession are sufficiently large. Is supplied with a maximum level of 100% and is lit at a luminance of 100%, and in the latter half sub-frame period T202, the gradation level is increased or decreased according to the average gradation level of two image signals input continuously. Are supplied and are lit at 10%, 20% and 10% brightness. The 10% period is a period in which the gradation level obtained by averaging the gradation level of the moving object and the gradation level of the stationary background is converted by the second gradation conversion circuit. The number in the area indicating the display state of the image indicates the luminance when the maximum capability of display luminance is 100%. For example, C surrounded by a dotted line indicates luminance of 40%.

  As a result, when the gradation level of the input image signal is sufficiently small, the display unit A of the moving object and the display unit B of the stationary background have the minimum in the second subframe period. Since the gradation level is supplied, a moving image quality improvement effect can be obtained as in the case of the black insertion type image display device shown in FIGS.

  FIG. 40 shows how the brightness distribution looks for an observer who has watched a moving object when an image as shown in FIG. 39 is displayed.

Compared to the case of the image display apparatus according to the fourth embodiment shown in FIG. 28, the broken line indicating the change in brightness at the boundary between the moving object and the background is different in the boundary portion on the left end and the right boundary portion of the object. It can be seen that is resolved. In addition, unlike the image display device proposed in Patent Document 1 shown in FIG.

  Also in the seventh embodiment, as in the fourth embodiment, the upper limit L1 of the gradation level of the image signal supplied in one subframe period and the gradation of the image signal supplied in the other subframe period. The upper limit value L2 of the level can be set so as to satisfy the relationship of L1 ≧ L2. Thus, even when the assumed luminance of the input image signal is maximum, a luminance difference of a certain degree or more is provided between the first half subframe period and the second half subframe period, so that motion blur can be reduced.

  Also in the seventh embodiment, as in the fourth embodiment, the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period is an appropriate gamma luminance characteristic. As shown in the figure, a threshold value that is a criterion for determining the gradation level of the image signal in each subframe period, and a gradation level of the image signal that is increased / decreased according to the input image signal and supplied in each subframe period Can be set. Thereby, an image can be displayed on the display element by gradation expression having an appropriate luminance gamma characteristic with respect to the input image signal.

  Further, also in the seventh embodiment, as in the fourth embodiment, the gradation of the image signal in each subframe period in accordance with the temperature level signal from the temperature sensor IC 20 that detects the panel temperature or its surrounding temperature. It is possible to set a threshold value serving as a level determination criterion and a gradation level of an image signal that is increased or decreased according to an input image signal and is supplied in each subframe period. Thereby, even when the liquid crystal panel 10 is used, the relationship between the input image signal and the brightness perceived by the observer can be kept constant regardless of the temperature condition.

  Further, in the seventh embodiment, as in the fifth embodiment, when the input image signal is composed of image signals having a plurality of color components, the gradation level of the input image signal is the highest. The ratio between the luminances displayed for each subframe period for color components other than the color components (for example, the luminance displayed in the first half subframe period of blue and green and the luminance displayed in the second subframe period) The ratio between the luminances displayed for each subframe period for the color component having the highest gradation level of the input image signal (the luminance displayed for the first subframe period of red) The gradation level of the image signal supplied in each subframe period can be set so as to be the same as the ratio to the luminance displayed in the latter subframe period. Thereby, the ratio of the luminance of each color is maintained appropriately, and deterioration of image quality due to an incorrect color balance can be prevented.

(Embodiment 8)
In the eighth embodiment, image display of one frame period is performed by the total amount of time integration of luminance displayed in three subframe periods, and in the subframe period that is the temporal center (center) of one frame period. An image signal having a gradation level that is increased or decreased according to the maximum gradation level or the gradation level of the input image signal is supplied, and in the first and last subframe periods before and after the temporal center (center). Describes a case where an image signal is displayed by supplying an image signal having a gradation level that is increased or decreased according to the minimum gradation level or the gradation level of the input image signal.

  FIG. 41 is a block diagram showing the main configuration of the eighth embodiment in the controller LSI 40 of FIG.

As shown in FIG. 41, the controller LSI 40D as display control means of the eighth embodiment includes a line buffer 41 as line data storage means, a timing controller 42 as timing control means, and a frame as frame storage data selection means. A memory data selector 43, a gradation conversion source selector 52 as gradation conversion source selection means, a first gradation conversion circuit 44 as first gradation conversion means, and a second floor as second gradation conversion means. A tone conversion circuit 45 and an output data selector 46 as output data selection means are provided.

  The input image signal is received and held by the line buffer 41 for each horizontal line. The line buffer 41 includes a reception port and a transmission port independently, and can perform reception and transmission at the same time.

  The frame memory data selector 43 is controlled by the timing controller 42 and transfers the image signal held in the line buffer 41 to the frame memory 30 by one horizontal line. The image signal held in the line buffer 41 is also transferred to the gradation conversion source selector 52.

  Also, the timing controller 42 reads the image signals previously input and stored in the frame memory 30 alternately from the two vertical positions on the screen one horizontal line at a time, alternately with the data transfer to the frame memory 30. Thus, the frame memory data selector 43 is switched and transferred to the first gradation conversion circuit 44 and the gradation conversion source selector 52. At this time, an image signal of ¼ frame before read out from the frame memory 30 is transferred to the first gradation conversion circuit 44, and 3/4 frame before read out from the frame memory 30 to the gradation conversion source selector 52. The image signal is transferred.

  The gradation conversion source selector 52 is controlled by the timing controller 42, and the image signal supplied from the line buffer 41 and the image signal of the previous 3/4 frame supplied from the frame memory data selector 43 correspond to the display timing. And switched to the second gradation conversion circuit 45.

  In the first gradation conversion circuit 44, the gradation level of the image signal of the previous 1/4 frame supplied from the frame memory data selector 43 is the maximum gradation level or the input image as in the case of the fourth embodiment. It is converted into a gradation level that is increased or decreased according to the gradation level of the signal.

  In the second gradation conversion circuit 45, the gradation level of the image signal supplied from the gradation conversion source selector 52 is the minimum gradation level or the level of the input image signal as in the case of the fourth embodiment. It is converted into a gradation level that is increased or decreased according to the gradation level.

  The output data selector 46 is controlled by the timing controller 42 so that the image signal output from the first gradation conversion circuit 44 and the image signal output from the second gradation conversion circuit 45 are in accordance with the display timing. It is switched and output as a panel image signal to the image display unit.

  Next, the operation of the image display apparatus according to the eighth embodiment will be described.

  FIG. 42 is a diagram illustrating the flow of an image signal for each horizontal period in the image display apparatus according to the eighth embodiment. Here, a period during which the image signals of the first to third lines of the Nth frame are input is shown.

Each rectangle shown in FIG. 42 indicates the transfer period of the image signal for one horizontal line. A rectangle [f, l] indicates that the image signal input to the horizontal l-th line of the f-th frame is transferred. For example, [N, 2] is input to the second horizontal line of the N-th frame. This indicates that the transferred image signal is transferred. The M1th line indicates a horizontal line at a position of ¼ screen from the first line of the screen. In the eighth embodiment, the horizontal line driven by the first gate voltage line of the second gate driver 14b. It is. The M2 line indicates a horizontal line from the first line of the screen to the position of the vertical position 3/4 screen. In the eighth embodiment, the horizontal line driven by the first gate voltage line of the fourth gate driver 14d. It is. Further, C1 and C2 are transferred with the image signals converted by the first gradation conversion circuit 44 and the second conversion circuit 45, respectively, using the input image signals of the frame and horizontal line shown in [] after the source as the sources. It shows that.

  As indicated by an arrow D1 in FIG. 42, the input image signal is received by the line buffer 41 for each horizontal line.

  In parallel with this, as indicated by an arrow D3, an image signal for one horizontal line stored in the frame memory 30 in the past by 1/4 screen from the vertical position of the currently input image signal is received from the frame memory 30. It is read out and supplied to the first gradation conversion circuit 44, converted by the first gradation conversion circuit 44 and output as a panel image signal. Similarly, the image signal for one horizontal line stored in the frame memory 30 in the past for 3/4 screens from the vertical position of the currently input image signal is read from the frame memory 30 and is stored in the second floor. It is supplied to the tone conversion circuit 45, converted by the second gradation conversion circuit 45, and output to the image display unit as a panel image signal. Further, the image signal for one horizontal line that is currently input and received by the line buffer 41 is supplied to the second gradation converting circuit 45 simultaneously with the writing to the frame memory 30 indicated by the arrow D2, and the second floor. It is converted by the tone conversion circuit 45 and output as a panel image signal.

  When a panel image signal for one horizontal line output from the controller LSI 40D is transferred to the first to fourth source drivers 13a to 13d by a clock signal and then a latch pulse signal is applied, display of pixels from each source voltage line A voltage corresponding to the luminance is output. At this time, a vertical shift clock signal or a gate start pulse signal is supplied to the gate driver corresponding to the line on which an image is displayed by supplying charges on the source voltage line, and the corresponding gate voltage line is It is turned on. On the other hand, in a gate driver that does not display an image, the enable signal is set to a low level and the gate voltage line is turned off. As described above, the operation of transferring the image signal for three lines to the display panel and displaying the image is repeated during the period in which the image signal for one horizontal line is input.

  In the case of FIG. 42, after the image signal for one horizontal line of the M2th line of the (N−1) th frame is transferred to the source driver as indicated by the arrow D4, the fourth gate driver is indicated as indicated by the arrow D5. The enable signal to 14d is set to the high level, and the start pulse signal and the vertical shift clock signal are supplied as indicated by arrows D6 and D7. As a result, as indicated by an arrow D8, the first gate voltage line of the fourth gate driver 14d whose display position corresponds to the screen M2 line is turned on, and an image is displayed. On the other hand, the enable signal to the first to third gate drivers 14a to 14c not corresponding to the display position is set to the off level, and the gate voltage line is turned off.

  Next, as shown by an arrow D9, after the image signal for one horizontal line of the M1th line of the (N−1) th frame is transferred to the source driver, as shown by an arrow D10, the image signal to the second gate driver 14b is sent. The enable signal is set to the high level, and the start pulse signal and the vertical shift clock signal are supplied as indicated by arrows D11 and D12. As a result, as indicated by an arrow D13, the first gate voltage line of the second gate driver 14b whose display position corresponds to the screen M1 line is turned on, and an image is displayed. On the other hand, enable signals to the first, third, and fourth gate drivers 14a, 14c, and 14d that do not correspond to the display position are set to the off level, and the gate voltage line is set to the off state.

Next, after an image signal for one horizontal line of the first line of the Nth frame is transferred to the source driver as indicated by an arrow D14, an enable signal to the first gate driver 14a is indicated as indicated by an arrow D15. Is set to the high level, and the start pulse signal and the vertical shift clock signal are supplied as indicated by arrows D16 and D17. As a result, as indicated by an arrow D18, the first gate voltage line of the first gate driver 14a whose display position corresponds to the first line of the screen is turned on, and an image is displayed. On the other hand, the enable signal to the second to fourth gate drivers 14b to 14d not corresponding to the display position is set to the off level, and the gate voltage line is turned off.

  FIG. 43 is a diagram showing a state in which the image signal on the screen is rewritten by repeating the control as shown in FIG. Here, a state is shown in which the image display is rewritten during the period in which the image signals of the Nth frame and the (N + 1) th frame are input.

  The diagonal arrows shown in FIG. 43 indicate the vertical position at which image rewriting for one line is performed and the rewriting timing. Ci [f] indicates that the image signal of the f-th frame is displayed by the image signal converted by the i-th gradation conversion circuit, and next until the image is rewritten to the same line. The image display is retained. In FIG. 43, the position where the image display converted by the first gradation conversion circuit 44 is held is white (no hatching), and the position where the image display converted by the second gradation conversion circuit 45 is held. It is expressed as gray (with hatching). The dotted line indicates the boundary position of the driven gate driver.

  Paying attention to the vertical position of one horizontal line on the screen, the display is performed by the image signal obtained by converting the input image signal by the first gradation conversion circuit 44 during the half of the input one frame period. It can be seen that the display by the image signal obtained by converting the input image signal by the second gradation conversion circuit 45 is performed in the ¼ period of the preceding and succeeding input one frame period. In this way, among the three periods in which images are actually displayed, the first 1/4 period, then the 1/2 period and the last 1/4 period of the input 1 frame period are respectively designated as the first and second periods. And the third sub-frame display period.

  As shown in FIG. 42, the display period by the image signal converted by the first gradation conversion circuit 44 and the image converted by the second gradation conversion circuit 45 for the image signal input as one frame. The display period by the signal is a half period of one input frame period. Therefore, in the first gradation conversion circuit 44 and the second gradation conversion circuit 45, the relationship between the gradation level of the input image signal and the gradation level of the image signal to be converted and output is the same as in the fourth embodiment. Thus, it is possible to improve the moving image quality by reducing the motion blur and obtain an appropriate gamma characteristic.

  In the image display apparatus according to the eighth embodiment, when displaying an image in which an object moves horizontally on a stationary background, if the gradation level of an input image signal is sufficiently small, any screen position In FIG. 5, since the image signal of the minimum gradation level is supplied in the first subframe period and the third subframe period, it is the same as in the case of the black insertion type image display device shown in FIGS. , The video quality improvement effect can be obtained.

  In the image display apparatus according to the eighth embodiment, the luminance associated with the passage of time on one horizontal line in the screen in the case where the display luminance of the stationary background and the moving object is the same as in the fourth embodiment shown in FIG. The state of change is shown in FIG.

  In FIG. 44, the horizontal axis shows the state of luminance in the horizontal direction on the screen, and the vertical axis shows the passage of time, representing screen display for a three-frame period.

As shown in FIG. 44, in the image display apparatus according to the eighth embodiment, one frame period T10.
1, three subframe periods T301 to T303 are provided, and in the stationary background display portion B, the gradation level of the input image signal is small. Therefore, in the second subframe period T302, the input image signal A gradation level that is increased or decreased according to the gradation level is supplied and turned on at a luminance of 40%. In the first subframe period T301 and the third subframe period T303, 0% is supplied as a minimum luminance level and is turned off. Yes. On the other hand, since the gradation level of the input image signal is sufficiently large in the moving object display unit A, 100% is supplied as the maximum level in the second subframe period T302, and the first sub-light is turned on. In the frame period T301 and the third subframe period T303, a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and the light is lit at a luminance of 20%. The number in the area indicating the display state of the image indicates the luminance when the maximum capability of display luminance is 100%. For example, C indicates luminance of 0%.

  FIG. 45 shows how the brightness distribution looks for an observer who has watched a moving object when an image as shown in FIG. 44 is displayed.

  In FIG. 45, it can be seen that the phenomenon that the broken line of the luminance change differs between the left end and the right end of the moving object as in the fourth embodiment shown in FIG. Further, unlike the image display device proposed in Patent Document 1 shown in FIG. 53, a portion having a higher or lower luminance than originally does not occur.

  Also in the eighth embodiment, as in the fourth embodiment, the gradation level of the image signal is changed in each subframe period in accordance with the temperature level signal from the temperature sensor IC 20 that detects the panel temperature or the surrounding temperature. It is possible to set a threshold value as a determination criterion and a gradation level of an image signal that is increased or decreased according to an input image signal and is supplied in each subframe period. Thereby, even when the liquid crystal panel 10 is used, the relationship between the input image signal and the brightness perceived by the observer can be kept constant regardless of the temperature condition.

  Further, in the eighth embodiment, as in the fifth embodiment, when the input image signal is composed of image signals of a plurality of color components, the gradation level of the input image signal is the highest. The ratio between the luminances that are displayed for each subframe period for color components other than the color components is the ratio between the luminances that are displayed for each subframe period for the color component having the highest gradation level of the input image signal. The gradation level of the image signal supplied in each subframe period can be set so as to be the same as the ratio. Thereby, the ratio of the luminance of each color is maintained appropriately, and deterioration of image quality due to an incorrect color balance can be prevented.

  In the first to seventh embodiments, an image display apparatus that displays an image for one frame period by the total amount of time integration of luminance displayed in two subframe periods will be described. In the eighth embodiment, Although an image display apparatus has been described in which image display for one frame period is performed by the total amount of time integration of luminance displayed in three subframe periods, the present invention is not limited to this, and n (n is 2 or more). The present invention can also be applied to an image display apparatus that displays an image for one frame period based on the total amount of time integral of luminance displayed in (integer) subframe periods.

For example, when image display is performed for one frame period by the total amount of time integration of luminance displayed in n (n is an integer of 2 or more) subframe periods, the time of one frame period during which image display is performed The total amount of time integration of the luminance displayed in the n subframe periods in the subframe period that is closest to the center (when n is an odd number) or closest to the center (when n is an even number) is the input image An image signal having the maximum gradation level is supplied in a range not exceeding the luminance level corresponding to the gradation level of the signal. Furthermore, if the total amount of time integration of luminance displayed in the supplied subframe period does not reach the luminance corresponding to the gradation level of the input image signal, the center or the subframe period closest to the center is further displayed. In the subframe periods before and after, the total amount of time integration of the luminance displayed in the supplied n subframe periods is input both before and after, in the order of before and after, or in the order of after and before. An image signal having the maximum gradation level is supplied within a range not exceeding a luminance level corresponding to the gradation level of the image signal. If the total amount of time integration of the luminance displayed in the supplied subframe period still does not reach the luminance corresponding to the gradation level of the input image signal, then, in the subframe periods before and after that, n Control is continued to supply an image signal having the maximum gradation level within a range in which the total amount of time integration of luminance displayed in one subframe period does not exceed the luminance level corresponding to the gradation level of the input image signal. When the total amount of time integration of luminance displayed in the supplied subframe period reaches the luminance corresponding to the gradation level of the input image signal, the image signal having the minimum gradation level in the remaining subframe period Supply.

  In addition, when image display is performed for one frame period by the total amount of time integration of luminance displayed in n (n is an odd number of 3 or more) subframe periods, the image is displayed in order from the earliest in time or the latest. Of the n subframe periods referred to as the first subframe, the second subframe,..., The nth subframe, in order from the first one, the first one serving as the temporal center of one frame period in which image display is performed. The m subframe period is set to m = (n + 1) / 2, and (n + 1) / 2 threshold values are set to T1, T2,..., T [(( n + 1) / 2], when the gradation level of the input image signal is equal to or less than the threshold value T1, the image of the gradation level that is increased or decreased according to the gradation level of the input image signal in the m-th subframe period Supply the signal It supplies an image signal of the minimum gradation level in the other sub frame periods. When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the image signal having the maximum gradation level is supplied in the m-th subframe period, and the (m-1) th subframe. In the period and the (m + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and in the other subframe period, an image signal having the minimum gradation level is supplied. Supply. Further, when the gradation level of the input image signal is larger than the threshold value T2 and equal to or less than the threshold value T3, the maximum gradation is obtained in the m-th subframe period, the (m-1) th subframe period, and the (m + 1) th subframe period. Level image signal is supplied, and in the (m−2) th subframe period and the (m + 2) th subframe period, an image signal of a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and the other subframes In the period, an image signal with the minimum gradation level is supplied. Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx−1 (x is an integer of 4 or more) and equal to or smaller than the threshold value Tx, from the [m− (x−2)] th subframe period. An image signal having the maximum gradation level is supplied in each subframe period up to the [m + (x−2)] th subframe period, and the [m− (x−1)] th subframe period and the [m + (x -1)] In the sub-frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and in the other sub-frame period, an image signal having the minimum gradation level is supplied. Supply.

Further, when the image display of one frame period is performed by the total amount of time integration of luminance displayed in n (n is an even number of 2 or more) subframe periods, the image is displayed in order from the earliest in time or latest. The n subframe periods referred to as the first subframe, the second subframe,..., The nth subframe, in order from the first, are closest to the temporal center of one frame period in which image display is performed. Two m1 subframe periods and m2 subframe periods are set to m1 = n / 2 and m2 = n / 2 + 1, and n / 2 thresholds are set in order from the smallest value to the gradation level of the image signal. As T1, T2,..., T [n / 2], when the gradation level of the input image signal is equal to or lower than the threshold value T1, the input image is displayed in the m1st subframe period and the m2th subframe period. Supplying gradation level image signal to be increased or decreased in accordance with the gradation level of the signal and provides the minimum image signal of the gradation level in the other sub frame periods. Further, when the gradation level of the input image signal is larger than the threshold value T1 and equal to or less than the threshold value T2, the image signal having the maximum gradation level is supplied in the m1 subframe period and the m2 subframe period. In the (m1-1) th subframe period and the (m2 + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and the minimum in other subframe periods. A gradation level image signal is supplied. When the gradation level of the input image signal is greater than the threshold value T2 and equal to or less than the threshold value T3, the m1st subframe period, the m2th subframe period, the m1-1 subframe period, and the m2 + 1 subframe. An image signal having the maximum gradation level is supplied in the period, and an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied in the m1-2 subframe period and the m2 + 2 subframe period. In the other subframe period, an image signal having the minimum gradation level is supplied. Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx-1 (x is an integer of 4 or more) and is equal to or smaller than the threshold value Tx, the [m1- (x-2)] th subframe period starts. The image signal having the maximum gradation level is supplied in each subframe period up to the [m2 + (x−2)] th subframe period, and the [m1− (x−1)] th subframe period and the [m2 + (x -1)] In the sub-frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied, and in the other sub-frame period, an image signal having the minimum gradation level is supplied. .

At this time, the upper limit value of the gradation level of the image signal supplied in the first subframe period, the second subframe period,..., The nth subframe period is L1, L2,. Among the subframe periods, the temporal center of one frame period in which image display is performed or the subframe period closest to the center is defined as a jth subframe period, and i is an integer between 0 and j,
L [j−i] ≧ L [j− (i + 1)],
L [j + i] ≧ L [j + (i + 1)],
The upper limit value of the gradation level image signal can be determined for each subframe period so as to satisfy the relationship, and this can be supplied as the maximum value of the gradation level of the image signal in each subframe period.

  By such control, the temporal center of gravity position of the display luminance can be fixed at the temporal center of one frame period or a position closest to the center, so that the conventional image display disclosed in Patent Document 1 is performed. It is possible to suppress deterioration in image quality due to incorrect luminance or color balance, which occurs when the temporal gravity center position of display luminance changes according to input gradation in the apparatus. In addition, since subframe periods having different luminance differences are provided, it is possible to improve the degradation of moving image quality due to motion blur that occurs in a conventional general hold-type image display device. In addition, when displaying the maximum gradation level, it is possible to suppress the decrease in the maximum luminance and the contrast ratio that occurs in the black insertion type image display device provided with the minimum luminance display.

(Embodiment 9)
In the ninth embodiment, in the image display method for one frame period based on the total amount of time integral values of luminance displayed in the first and second half subframe periods, the gamma luminance of the image display apparatus using a digital input source driver is used. A case where the characteristics can be changed will be described.

In the ninth embodiment, when the gradation level of the input image signal is 50% or less in the method of filling the gradation levels for the first half and the second half subframe of one frame, the other of the first half and the second half is not 0%. For example, there will be described a case where there are several percent, and when the proportion is 50% or more, one of the first half and the second half is not 100% but 100% is insufficient, for example, several percent. The gradation levels are distributed between the first half and the second half so that one of the first half and the second half is more than the gradation level of at least half of the other. Preferably, the effect of the present invention can be obtained when one of the first half and the second half is 10% or less of the other, more preferably 2% or less (for example, one gradation is distributed among 256 gradations).

  FIG. 60 is a block diagram showing an example of the basic configuration of the image display apparatus according to the ninth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which show | plays the effect similar to FIG. 1, and the description is abbreviate | omitted.

  As shown in FIG. 60, the image display apparatus according to the ninth embodiment has almost the same configuration as the image display apparatus in FIG. 1, but the source drivers 13Da to 13Dd are digital input source drivers, and the temperature sensor Instead of the IC 20, the gamma luminance characteristic setting switch 21 as gamma luminance characteristic setting means for changing the gamma luminance characteristic to any one of “2.1”, “2.2” and “2.3” by switching and Thus, the difference is that a controller LSI 40E that performs display control by switching the gamma luminance characteristic is provided. Here, the gamma luminance characteristic setting switch 21 is provided in place of the temperature sensor IC 20, but may be provided together with the temperature sensor IC 20.

  Each of the digital input source drivers 13Da to 13Dd receives a panel image signal as digital display data, selects one of preset voltages according to the value of each digital display data, and outputs it as a gradation voltage. is there. For example, in the case of an 8-bit input source driver, 256 output gradation voltages are set in advance, and 256 values from 0 to 255 determined by the input 8-bit digital display data are used. The gradation voltage uniquely determined can be selected and output.

  61 is a block diagram showing a configuration example of the controller LSI 40E of FIG.

  As shown in FIG. 61, the controller LSI 40E as display control means of the ninth embodiment includes a line buffer 41 as line data storage means, a timing controller 42 as timing control means, and a frame as frame storage data selection means. Memory data selector 43, first gradation conversion circuit 44E as first gradation conversion means to which a gamma characteristic setting signal is inputted, and second floor as second gradation conversion means to which a gamma characteristic setting signal is inputted. A tone conversion circuit 45E and an output data selector 46 as output data selection means are provided.

  The line buffer 41 receives the inputted input image signal for each horizontal line and temporarily holds it. The line buffer 41 includes a reception port and a transmission port independently, and can perform reception and transmission at the same time.

  The timing controller 42 controls the frame memory data selector 43 to alternately switch the timing of data transfer to the frame memory 30 and data reading from the frame memory 30. Further, the timing controller 42 controls the output data selector 46 to alternately select the output timings from the first gradation conversion circuit 44E and the second gradation conversion circuit 45E. That is, the timing controller 42 switches the first half subframe period and the second half subframe period with respect to the output data selector 46, as will be described later.

  The frame memory data selector 43 is controlled by the timing controller 42 to transfer the input image signal held in the line buffer 41 by one horizontal line to the frame memory 30 and to input the frame memory one frame before. The image signal stored in 30 is alternately selected to read out one horizontal line at a time, and the read data is transferred to the second gradation conversion circuit 45E.

  The first gradation conversion circuit 44E converts the gradation level of the input image signal supplied from the line buffer 41 to the gradation level of the first half subframe period of the two subframes according to the lookup table.

  The second gradation conversion circuit 45E converts the gradation level of the image signal supplied from the frame memory data selector 43 into the gradation level of the second half subframe period of the two subframes according to the lookup table.

  In the ninth embodiment, the first gradation conversion circuit 44E and the second gradation conversion circuit 45E are configured by a look-up table in which output values corresponding to input values are stored in advance, and gamma luminance characteristics. One of the three types of lookup tables determined according to the gamma value from the setting switch 21 is selected to determine the output value. Although the lookup table is used in the ninth embodiment, the output value can also be determined by switching the arithmetic expression of the arithmetic circuit.

  The output data selector 46 is controlled by the timing controller 42 and alternately selects the image signal output from the first gradation conversion circuit 44E and the image signal output from the second gradation conversion circuit 45E for each line. And output as a panel image signal.

  The operation of the image display apparatus according to the ninth embodiment having the above-described configuration is merely the source drivers 13Da to 13Dd being changed to those of the digital input method, and is basically the same as that in the first embodiment, and is therefore described here. The description is omitted.

  Next, an image display method according to the ninth embodiment will be described.

  In the image display method according to the ninth embodiment, the second half subframe is referred to as subframe α, and the gradation of the input image signal to be input when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value. In order to supply an image signal with a gradation level that is increased or decreased according to the level, and when the gradation level of the input image signal is larger than the threshold value, the vicinity of the maximum gradation level (the first half and the second half of the frame) The image signal is converted by the second gradation conversion circuit 45E so that the image signal of one half or less, preferably 10% or less, more preferably 2% or less, is supplied.

  Also, the first half subframe is called a subframe β, and when the gradation level of the input image signal is equal to or less than a uniquely determined threshold, one near the minimum gradation level (one of the first half and the second half of the frame is the other). Less than half, preferably 10% or less, more preferably 2% or less), and when the gradation level of the input image signal is larger than the threshold value, the input image signal to be input The image signal is converted by the first gradation conversion circuit 44E so that the image signal of the gradation level that is increased or decreased in accordance with is supplied.

  A method of allocating gradation levels to the first half subframe period and the second half subframe period will be described.

  In the ninth embodiment, a description will be given using a 5-bit digital input source driver for the sake of simplicity. In particular, it is not necessary to limit the number of input bits of the source driver, and generally 256 gradations are used. A source driver of an 8-bit input type that can be displayed is often used.

The luminance level of the liquid crystal panel 10 is determined by the output gradation voltage and the voltage-transmittance characteristics (VT characteristics) of the liquid crystal panel 10 to be used according to the digital display data input to the source drivers 13Da to 13Dd. However, in the ninth embodiment, the case where the source drivers 13Da to 13Dd with 5-bit digital input are used is shown, and the luminance level of the liquid crystal panel 10 with respect to the input digital data is a value shown in (Table 1) below The gradation voltage is set so that That is, the reference voltage is set so that the gamma luminance characteristics of the source drivers 13Da to 13Dd are 2.2.

  In the ninth embodiment, the gamma luminance characteristics of the image display apparatus can be changed by appropriately combining the gradation levels of the first half and second half subframes using the above-described digital input source drivers 13Da to 13Dd. That is, most of the general image signals are output as a gamma value = 2.2 assuming the gamma luminance characteristic of a CRT (cathode ray tube) which has been a mainstay image display device in the past. In the ninth embodiment, the gamma luminance characteristic of the image display device is changed with the gamma luminance characteristic setting switch 21 so that an optimal gamma value can be selected for the displayed screen and the image on the display screen can be easily viewed. Can be changed to one of three types of “2.1”, “2.2”, and “2.3”.

  Specifically, the look-up tables in the first gradation conversion circuit 44E and the second gradation conversion circuit 45E are looked up for 2.2 according to the gamma characteristic setting signal input from the gamma luminance characteristic setting switch 21. This is realized by switching to one of the lookup table B for A and 2.1 and the lookup table C for 2.3.

  Next, in the look-up table A (gamma luminance characteristic 2.2), the gradation level of the input image signal, the digital data output to the source drivers 13Da-13Dd in the first half and second half subframe periods, and the first half, second half The gradation level of each subframe period and, as a result, the brightness perceived by the observer's eyes, the display luminance in the first and second subframe periods is time-integrated in one frame period (perceived brightness). Is shown in Table 2 below.

  The relationship between the gradation level of the input image and the target luminance level of the luminance image display device is expressed by the following equation.

Target luminance level of image display apparatus = (tone level of input image) ^γ (Equation 100)
γ = Gamma luminance characteristic of image display device (gamma value set by switch)
The relationship between the gradation level supplied in each of the first and second subframe periods and the value [perceived brightness] obtained by time integration in one frame period is expressed by the following equation.

Luminance time integral [perceived brightness]
= {(Gradation level of first half subframe) ^Dγ
+ (Gradation level of the second half subframe) ^Dγ } / 2 (Formula 101)
Dγ = 2.2 = Gamma luminance characteristics of source driver Among the relationships among the gradation level of the input image signal, the gradation levels of the first half and the second half subframe, and the perceived brightness shown in (Table 2) above, the target FIG. 62 shows six examples with different luminance levels.

As can be seen from FIG. 62, when the gradation level of the input image signal is less than 50%, that is, 25.81, the second half subframe that is increased or decreased according to the gradation level of the input image signal and the gradation near the minimum. The perceived brightness is determined by the combination of the first half subframes of the level. When the luminance level of the input image signal is 50% or more, that is, 74.19% or 83.67%, the first half subframe that is increased or decreased according to the gradation level of the input image signal, and the gradation around the maximum. The perceived brightness is determined by the combination of the second half subframes of the level.

  Similarly, the correspondence between lookup table B and lookup table C is shown in the following (Table 3) and (Table 4). Also in this case, the relationship of Expression 100 and Expression 101 is established, γ = 2.1 in the lookup table B, and γ = 2.3 in the lookup table C.

  In the lookup table used in the ninth embodiment, the table data is selected so that the error is within ± 1.5% with respect to the set gamma luminance characteristic of the image display apparatus.

  FIG. 63 is a graph showing the relationship between the gradation level of the input image and the value [perceived brightness] obtained by time integration in one frame period when the look-up tables A to C are used.

As described above, in the image display device according to the ninth embodiment, the input image signal input when the gradation level of the input image signal is equal to or lower than the threshold value uniquely determined by the first gradation conversion circuit 44E. If the input image signal has a gradation level greater than the threshold value, an image signal near the maximum gradation level is displayed. When the image signal is converted so as to be supplied and the gradation level of the input image signal is equal to or lower than the threshold value uniquely determined by the second gradation conversion circuit 45, the image signal near the minimum gradation level is In addition, when the gradation level of the input image signal is larger than the threshold value, the image signal is supplied so that the image signal of the gradation level that is increased or decreased according to the input image signal is supplied. By converting It is possible to change the gamma luminance characteristic of the image display device. That is, by appropriately combining the gradation levels of the first half subframe and the second half subframe, the motion blur of the hold-type image display apparatus is improved by reducing motion blur without reducing the maximum value in time integration of a certain luminance. However, the gamma luminance characteristics of the image display device can be changed.

In the ninth embodiment, in order to change the gamma luminance characteristic of the image display device, the gradation level that is increased or decreased by two subframes and the image signal near the minimum gradation level, or the vicinity of the maximum gradation level. The brightness perceived in one frame period is controlled by supplying the image signal of the gradation level that is increased or decreased, but VT due to other uses, for example, temperature correction of the liquid crystal panel or change of the liquid crystal material It can also be used for gradation correction due to a difference in characteristics.
(Embodiment 10)
In the first to ninth embodiments, the image display control means of the image display apparatus of the present invention can be configured by hardware. However, in the tenth embodiment, the image display control means of the image display apparatus of the first to ninth embodiments. A case in which is configured by software will be described.

  FIG. 64 is a block diagram illustrating a configuration example when the image display control unit of the image display apparatus according to the tenth embodiment performs processing by a computer.

  As shown in FIG. 64, the image display control means 40F of the image display apparatus 1 of the tenth embodiment includes a control means 401 composed of a CPU (Central Processing Unit) and the image display methods of the first to ninth embodiments described above. A ROM 402 as a readable recording medium storing the display control program describing the processing procedure to be executed by the control and the data, and a RAM 403 used by the control means 401 as a work memory.

  The readable recording medium is a storage device such as various IC memories, a hard disk (HD), an optical disk (for example, CD), and a magnetic recording medium (for example, FD), and the display control program of the present invention and its data can be read by a computer. A display control program and its data read from the recording medium are stored in the RAM 403 from the ROM 402 and executed by the control means 401.

The control means 401 is based on the display control program of the present invention and its data.
In the temporal center of one frame period in which image display is performed or the subframe period closest to the center, the total amount of time integration of luminance displayed in n (an integer of 2 or more) subframe periods is input. Processing (means) for supplying an image signal having a maximum gradation level to a display panel 10 as an image display unit within a range not exceeding a luminance level corresponding to the gradation level of the image signal
When the total amount of time integration of luminance displayed in the center or the subframe period closest to this center does not reach the luminance corresponding to the gradation level of the input image signal, the center or the sub-proximal subcenter to this center is displayed. In the subframe periods before and after the frame period, the maximum level in the range in which the total amount of time integration of luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal. Processing (means) for supplying a tone level image signal to the display panel 10 as an image display unit;
If the total amount of luminance time integral displayed in the center or the subframe period closest to the center and the subframe periods before and after the center does not reach the luminance corresponding to the gradation level of the input image signal, In the preceding and succeeding subframe periods, the maximum gradation level in a range where the total amount of time integration of the luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal The total amount of luminance time integration corresponding to the gradation levels of all the supplied image signals is set to the gradation level of the input image signal. Repeat until the corresponding brightness is reached, and when it reaches, supply the image signal of the gradation level that is minimum or smaller than the predetermined value to the image display unit in the remaining subframe period Sequentially executed and Rusuru process (means).

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
Image display is performed in n subframe periods including a first subframe, a second subframe,..., An nth subframe in order from the earliest in time or in order from the latest. The m-th subframe period that is the temporal center of the frame period is set by m = (n + 1) / 2,
When (n + 1) / 2 threshold values are set to T1, T2,..., T [(n + 1) / 2] in ascending order of values with respect to the gradation level of the image signal,
When the gradation level of the input image signal is equal to or lower than the threshold value T1, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal is displayed in the mth subframe period. A process of supplying the image display unit with an image signal having a gradation level that is minimum or smaller than a predetermined value in the other subframe period,
When the gradation level of the input image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the image display unit displays an image signal having a gradation level that is maximum or greater than a predetermined value in the m-th subframe period. In the (m-1) th subframe period and the (m + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the others. A process of supplying an image signal having a gradation level smaller than or smaller than a predetermined value to the image display unit in the subframe period of
When the gradation level of the input image signal is larger than the threshold value T2 and equal to or smaller than the threshold value T3, the maximum or predetermined value is applied in the m-th subframe period, the m-1 subframe period, and the m + 1 subframe period. An image signal having a gradation level greater than the value is supplied to the image display unit, and the gradation is increased or decreased in accordance with the gradation level of the input image signal in the (m-2) th subframe period and the (m + 2) th subframe period. A process of supplying an image signal of a level to the image display unit, and supplying an image signal of a gradation level smaller than a minimum or a predetermined value to the image display unit in other subframe periods;
Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx−1 (x is an integer of 4 or more) and equal to or smaller than the threshold value Tx, the [m− (x−2)] th subframe period. To the image display unit is supplied with an image signal having a maximum gradation level or greater than a predetermined value in each subframe period from the [m + (x-2)] th subframe period to the [m + (x-2)] th subframe period. In the sub-frame period and the [m + (x−1)]-th sub-frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the others. In the sub-frame period, a process of supplying an image signal with a gradation level smaller than the minimum or a predetermined value to the image display unit is executed.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
Image display is performed in n subframe periods including a first subframe, a second subframe,..., An nth subframe in order from the earliest in time or in order from the latest. Two m1 subframe periods and m2 subframe periods closest to the temporal center of the frame period are set by m1 = n / 2 and m2 = n / 2 + 1,
When n / 2 threshold values are set to T1, T2,..., T [n / 2] in order from the smallest value with respect to the gradation level of the image signal,
When the gradation level of the input image signal is equal to or lower than the threshold T1, the gradation level image is increased or decreased in accordance with the gradation level of the input image signal in the m1st subframe period and the m2nd subframe period. Processing (means) for supplying a signal to the display panel 10 serving as an image display unit, and supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the display panel 10 serving as an image display unit in other subframe periods. ,
When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, an image signal having a gradation level that is maximum or greater than a predetermined value in the m1st subframe period and the m2th subframe period. An image signal having a gradation level that is supplied to the display panel 10 serving as an image display unit and that is increased or decreased in accordance with the gradation level of the input image signal in the (m1-1) th subframe period and the (m2 + 1) th subframe period. Processing (means) for supplying to the display panel 10 which is a display unit, and supplying an image signal having a gradation level which is minimum or smaller than a predetermined value to the display panel 10 which is an image display unit in other subframe periods;
When the gradation level of the input image signal is greater than the threshold value T2 and equal to or less than the threshold value T3, the m1st subframe period, the m2th subframe period, the m1-1 subframe period, and the m2 + 1 subframe period Is supplied to the display panel 10 which is the image display unit, and the gradation level of the input image signal in the m1-2 subframe period and the m2 + 2 subframe period. Is supplied to the display panel 10 as an image display unit, and an image signal with a gradation level smaller than a minimum value or smaller than a predetermined value in the other subframe period is used as the image display unit. Processing (means) to be supplied to the display panel 10;
Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx−1 (x is an integer of 4 or more) and equal to or smaller than the threshold value Tx, the [m1- (x−2)] th subframe period. To [m2
In each subframe period up to the + (x−2)] subframe period, an image signal having a maximum gradation level or greater than a predetermined value is supplied to the display panel 10 as an image display unit, and the [m1- (
x-1)] In the subframe period and the [m2 + (x-1)] subframe period, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal is input to the image display unit. In the other subframe period, processing (means) for supplying an image signal having a gradation level smaller than a minimum value or smaller than a predetermined value to the display panel 10 as an image display unit is executed.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
One subframe period is a subframe α period, the other subframe is a subframe β period,
An image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period when the gradation level of the input image signal is equal to or less than a uniquely determined threshold value. Is supplied to the display panel 10 that is an image display unit, and an image signal having a gradation level that is minimum or smaller than a predetermined value in the subframe β period is supplied to the display panel 10 that is an image display unit;
When the gradation level of the input image signal is larger than the threshold value, an image signal having a gradation level that is maximum or larger than a predetermined value in the subframe α period is supplied to the display panel 10 that is an image display unit, and the subframe In the β period, processing (means) for supplying an image signal of a gradation level that is increased or decreased according to the input image signal to the display panel 10 that is an image display unit is executed.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
One subframe period is a subframe α period, and the other subframe is a subframe β period. Two gradation level thresholds T1 and T2 are determined, and the threshold T2 is larger than the threshold T1.
When the gradation level of the input image signal is equal to or lower than the threshold value T1, the image display unit displays the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period. A process (means) for supplying the display panel 10 with an image signal having a gradation level that is minimum or smaller than a predetermined value in the subframe β period;
When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period. This is supplied to the display panel 10 which is an image display unit, and in the subframe β period, the level is lower than the gradation level supplied in the subframe α period, and is increased or decreased according to the gradation level of the input image signal. Processing (means) for supplying an image signal having a gradation level to the display panel 10 as an image display unit;
When the gradation level of the input image signal is larger than the threshold value T2, an image signal having a gradation level that is maximum or larger than a predetermined value is supplied to the display panel 10 that is an image display unit in the subframe α period, and the subframe In the β period, processing (means) for supplying an image signal of a gradation level that is increased or decreased according to the input image signal to the display panel 10 that is an image display unit is executed.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
One subframe period is a subframe α period, the other subframe is a subframe β period, and two gradation level thresholds T1 and T2 are determined. T2 is a value greater than T1, Level L is uniquely determined,
When the gradation level of the input image signal is equal to or lower than the threshold value T1, in the sub-frame α period, the image display unit outputs the gradation level image signal that is increased or decreased according to the gradation level of the input image signal. Processing (means) for supplying to a display panel 10 and supplying an image signal having a gradation level smaller than a minimum or a predetermined value to the display panel 10 as an image display unit in the subframe β period;
When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the gradation level L is supplied in the subframe α period, and the input image signal is input in the subframe β period. Processing (means) for supplying an image signal of a gradation level increased or decreased to the display panel 10 as an image display unit;
When the gradation level of the input image signal is larger than the threshold value T2, during the subframe α period, the image display unit displays the gradation level image signal that is increased or decreased according to the gradation level of the input image signal. A process (means) for supplying an image signal to a certain display panel 10 and supplying an image signal having a gradation level larger than a maximum value or a predetermined value to the display panel 10 as an image display unit is performed in the subframe β period.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
One subframe period is a subframe α period, the other subframe is a subframe β period,
A process (means) for estimating and generating a temporally intermediate frame image for two consecutively input images;
In the subframe α period, when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value, the image of the gradation level that is increased or decreased according to the gradation level of the input image signal A signal is supplied to the display panel 10 that is an image display unit, and when the gradation level of the input image signal is larger than a threshold value, the image signal having the maximum or higher gradation level than the threshold value is displayed on the display panel that is the image display unit Processing (means) to be supplied to 10,
In the sub-frame β period, when the gradation level of the image signal in the intermediate frame image is equal to or less than the threshold value, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the display panel 10 that is an image display unit, When the gradation level in the intermediate state frame image is larger than the threshold value, the image display unit displays the gradation level image signal that is increased or decreased according to the gradation level of the image signal in the intermediate state frame image. Processing (means) to be supplied to the display panel 10 is executed.

Alternatively, the control means 401 is based on the display control program of the present invention and its data.
One subframe period is a subframe α period, the other subframe is a subframe β period,
In the subframe α period, when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold value, the image of the gradation level that is increased or decreased according to the gradation level of the input image signal A signal is supplied to the image display unit, and when the gradation level of the input image signal is larger than the threshold value, an image signal having a maximum or larger gradation level is supplied to the display panel 10 that is an image display unit. Processing (means) to perform,
In the subframe β period, when the average value of the gradation level of the input image signal and the gradation level of the image signal input in the immediately preceding or succeeding one frame is equal to or less than the threshold value A gradation level that is increased or decreased according to the level of the average value when an image signal having a gradation level smaller than a minimum value or a predetermined value is supplied to the display panel 10 as an image display unit and the average value is larger than a threshold value The processing (means) for supplying the image signal to the display panel 10 as an image display unit is executed.

  As described above, it is possible to suppress the motion blur that occurs during the moving image display in the image display device while suppressing the decrease in the maximum luminance and the contrast.

(Embodiment 11)
In the eleventh embodiment, a liquid crystal television device that is a finished product using the image display device and the image display method of the first to tenth embodiments will be described.

  FIG. 65 is a block diagram showing a configuration example in Embodiment 11 of a liquid crystal television device using the image display device of the present invention.

  In FIG. 65, the liquid crystal television apparatus 1000 includes the image display apparatus 1 according to any of Embodiments 1 to 10 above, and a tuner unit 1001 that selects a channel of a television broadcast signal, and is selected by the tuner unit 1001. The television broadcast signal of the channel is input to the controller LSI 40 of the image display device 1 as an image signal.

  As described above, on the display screen of the liquid crystal television apparatus 1000, it is possible to obtain a high-quality image in which motion blur generated when displaying a moving image on the image display apparatus is suppressed while lowering the maximum luminance and contrast.

Embodiment 12
In the twelfth embodiment, a liquid crystal monitor device that is a finished product using the image display device and the image display method of the first to tenth embodiments will be described.

  FIG. 66 is a block diagram showing a configuration example in Embodiment 12 of a liquid crystal monitor device using the image display device of the present invention.

  In FIG. 66, the liquid crystal monitor device 2000 includes the image display device 1 according to any one of the first to tenth embodiments and a signal processing unit 2001 that performs signal processing on an external monitor signal such as a personal computer (PC). The monitor video signal output from the processing unit 2001 is input to the controller LSI 40 of the image display device 1 as an image signal.

As described above, on the display screen of the liquid crystal monitor device 2000, it is possible to obtain a high-quality image that suppresses motion blur that occurs when displaying a moving image on the image display device while suppressing a decrease in maximum luminance and contrast.

  In addition, although the image display method of the said Embodiment 1 was shown to be controlled with respect to each of the pixel part on a screen, also with respect to each of the image display methods of the said Embodiments 2-9, a pixel part unit ( For each pixel part).

  Further, although not specifically described in the first to twelfth embodiments, the gradation level refers to an input signal level, and the luminance level refers to a displayed brightness level.

  Further, although not particularly described in the first to twelfth embodiments, in the case where the plurality of subframe periods are three or more subframe periods, the gradation level that is sequentially distributed is one frame period, and the center portion thereof is the end. It is higher than the department. In addition, the luminance levels of the sub-frame images that are sequentially distributed are higher in the center than in the end in one frame period. Furthermore, the center-of-gravity variation of the time integral of luminance displayed in a plurality of subframe periods is within one subframe period.

  Here, in the first to twelfth embodiments, the case where display control is performed by dividing one frame period into two or three subframe periods has been mainly described. However, the present invention is not limited to this. The display can be controlled by being divided into two or more sub-frame periods. In this case, examples of various distribution methods for distributing the luminance levels assumed by the input image signal in each subframe period will be described in an organized manner. Note that the gradation level is adjusted so that the input image signal has the expected luminance level.

  Further, in the following description, in order to explain the distribution method in an easy-to-understand manner, the distribution method when the gradation level of the input image signal is gradually increased from a low level to a predetermined gradation level is described. According to the invention, according to the gradation level of the input image signal, based on the following distribution method, the distribution is instantaneously performed by a conversion process using a calculation process or a lookup table.

  67 to 71 are subframes for explaining examples of various distribution methods for distributing the luminance levels assumed by the input image signal to the image display unit in each subframe period in the image display device of the present invention. FIG. In FIGS. 67 to 71, one frame is composed of a plurality of strip-like subframes in the vertical direction, the dot portion indicates the process of distributing the brightness level to the subframe, and the shaded portion indicates the brightness level. The subframe is shown.

In FIG. 67 (a), when one frame is divided into integers of 2 or more (including both odd and even numbers, but here six, for example), the temporal center of one frame period in which image display is performed Alternatively, the luminance level assumed by the input image signal is allocated from the subframe closest to the center (here, for example, the left side may start from the right side) (dot portion). When the left subframe is full (shaded portion), the luminance level assumed by the input image signal is assigned to the right subframe closest to the center (dot portion). Further, when the right subframe is full (shaded portion), the luminance level assumed by the input image signal is assigned to the subframe adjacent to the left of the left subframe closest to the center (dot portion). Further, when the left subframe is full (shaded portion), the luminance level assumed by the input image signal is assigned to the subframe adjacent to the right of the right subframe closest to the center (dot portion). This is repeated sequentially, and the luminance level assumed for the input image signal to the image display unit is sequentially assigned from the center or the nearest subframe to the next and subsequent subframes. The remaining luminance level is distributed to the remaining subframes so that the luminance level is assumed to be the same as that assumed for the input image signal, and the distribution of the luminance level is completed.

  In FIG. 67 (b), when one frame is divided into three or more odd (for example, 5 in this case) subframes, the temporally subframe (for example, from the left side) of one frame period in which image display is performed. The luminance level assumed by the input image signal is distributed from the third) (dot portion). At this time, the reference value of the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to the subframes is the threshold, and the gradation level of the input image signal <threshold T1. When the center subframe is full (shaded portion; threshold value T1), the luminance level assumed by the input image signal is assigned to the left and right (front and back) subframes of the center subframe at the same time (dot portion). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Further, when the two left and right subframes are full (shaded portion; threshold T2), the luminance level assumed by the input image signal is simultaneously distributed to the left and right subframes of the left and right subframes (dot portion). ). At this time, the threshold value T2 <the gradation level of the input image signal. This operation is sequentially repeated. The gradation level value corresponding to the luminance level until the luminance level overflows in the central subframe is the threshold value T1, and the gradation level value corresponding to the luminance level until the luminance level overflows in the left and right subframes is the threshold value. T2. As the number of subframes increases, the number of thresholds also increases. As described above, by providing the thresholds T1 and T2, it is possible to speed up the control judgment when the luminance levels are distributed.

  In FIG. 67 (c), when one frame is divided into two or more even (here, 6) subframes, the left and right subframes (for example, the temporal center of one frame period in which image display is performed) The luminance level assumed by the input image signal is assigned simultaneously from the third (fourth from the left) (dot portion). At this time, the gradation level of the input image signal <the threshold value T1. When both the left and right subframes at the center are full (shaded portion; threshold T1), the luminance level assumed by the input image signal is simultaneously distributed to the two left and right subframes of the center left and right subframes ( Dot part). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Furthermore, when the two left and right subframes are full (shaded portion; threshold T2), the left and right subframes (second and fifth from the left) are further left and right subframes (1,6 from the left). At the same time, the brightness level assumed by the input image signal is assigned to (eye) (dot portion). At this time, the threshold value T2 <the gradation level of the input image signal. This operation is sequentially repeated.

  In FIG. 67 (d), one frame is divided into two subframes, and the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to each subframe. When the threshold value T is set as the reference value, the luminance level assumed by the input image signal is distributed from one of the two subframes (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When one of the subframes is full (shaded portion; threshold T), the luminance level assumed by the input image signal is assigned to the other subframe (dot portion). At this time, the threshold value T <the gradation level of the input image signal. In this case, the value of the gradation level corresponding to the luminance level that can be distributed to one subframe is set as the threshold value T.

In FIG. 68 (e), one frame is divided into two sub-frames, and the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to the sub-frames is shown. When threshold values T1 and T2 are set as reference values, the luminance level assumed by the input image signal is distributed from one of the two subframes (here, for example, the left side) (dot portion). At this time, the gradation level of the input image signal <the threshold value T1. When the gradation level of the input image signal reaches the threshold value T1 in one of the subframes, the luminance level assumed by the input image signal is also distributed to the other subframe (dot portion). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Further, the distribution of the luminance level assumed by the input image signal in one of the subframes is full (threshold value T2), and the luminance level assumed by the input image signal is distributed to the other subframe. (Dot part). At this time, the threshold value T2 <the gradation level of the input image signal.

  In FIG. 68 (f), one frame is divided into two sub-frames, and the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to the sub-frames is shown. When threshold values T1 and T2 are set as reference values, the luminance level assumed by the input image signal is distributed from one of the two subframes (dot portion). At this time, the gradation level of the input image signal <the threshold value T1. When the gradation level corresponding to the luminance level assumed by the input image signal in one of the subframes becomes the threshold T1, the luminance level distributed to the one subframe is temporarily fixed (distribution stopped) in the middle. The luminance level assumed by the input image signal is assigned to the other subframe (dot portion). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Further, when the distribution of the luminance level assumed by the input image signal in the other subframe is full (threshold value T2), the luminance level distribution fixing to one subframe is canceled, and one subframe is released. The remainder of the luminance level assumed by the input image signal is distributed and the process ends (dot portion). At this time, the threshold value T2 <the gradation level of the input image signal. This averages the luminance centroid.

  In FIG. 68 (g), one frame is divided into two subframes, and the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to the subframes is shown. When the threshold value T is set as the reference value, the luminance level assumed by the input image signal is assigned from one of the two subframes (here, the left side) (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When the gradation level of the input image signal reaches the threshold value T in one subframe, the one subframe is set to the maximum luminance, and the luminance level is set in the other subframe in consideration of the image state of the next one frame. Distribute. That is, when an image difference (motion) between the original one frame input image and the next one frame input image is observed and the difference is changed, the temporally intermediate state (intermediate) The remaining luminance level is assigned to the other sub-frame so that the input image signal of (estimated image of (2) is assumed to have the assumed luminance level. In one of the subframes, the distribution of luminance levels assumed by the input image signal is full. At this time, the threshold value T <the gradation level of the input image signal. This suppresses the pseudo contour.

  In FIG. 68 (h), one frame is divided into two subframes, and the gradation level corresponding to the luminance level when the luminance level assumed in the input image signal is sequentially distributed to the subframes is shown. When the threshold value T is set as the reference value, the luminance level assumed by the input image signal is assigned from one of the two subframes (here, the left side) (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When the gradation level of the input image signal reaches the threshold value T in one of the subframes, the one subframe has the maximum luminance, and in the other subframe, the input image of the original frame, the input image of the next frame, Is calculated, and the remaining luminance level assumed by the input image signal having the average value is distributed. In one of the subframes, the distribution of luminance levels assumed by the input image signal is full. At this time, the threshold value T <the gradation level of the input image signal.

FIGS. 69 (i) and 69 (j) show the same case where the subframe periods are different. As the subframe period is narrower, the impulse effect is obtained, and when the subframe period width is thick, the luminance center of gravity approaches the thick subframe period and becomes difficult to move. Therefore, the luminance center-of-gravity effect and the impulse effect can be changed by making the subframe at a predetermined position such as the center portion thicker or thinner in time as much as possible. 69 (i) can be adapted to FIGS. 67 (a) to 68 (h), and FIG. 69 (j) can be adapted to FIG. 67 (b).

  69 (k) is the same as that in FIG. 68 (e), but in addition to this, when the luminance level is filled from one subframe and the gradation level corresponding to this luminance level becomes the threshold value T1, This is a case where the luminance level is filled in the other subframe at the same time, but is distributed so that the difference between the gradation level or the luminance level distributed to both subframes is constant.

  In other words, one frame is divided into two subframes, and the threshold value T1 is used as a reference value of the gradation level corresponding to the luminance level when the luminance level assumed by the input image signal is sequentially distributed to the subframes. , T2 is set, the luminance level assumed by the input image signal is assigned from one of the two subframes (for example, the left side here) (dot portion). At this time, the gradation level of the input image signal <the threshold value T1. When the gradation level of the input image signal reaches the threshold value T1, the luminance level assumed by the input image signal in the other subframe is also changed to the difference between the gradation level or the luminance level distributed to the left and right subframes. Distribute at the same speed so that is constant (dot portion). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Furthermore, the distribution of the luminance level assumed by the input image signal in one subframe is full (threshold value T2), and the remaining luminance level assumed by the input image signal is distributed in the other subframe. The distribution process ends (dot portion). At this time, the threshold value T2 <the gradation level of the input image signal.

  In FIG. 69 (l), the difference from FIG. 68 (k) is that when the luminance level is filled from one subframe and the gradation level corresponding to this luminance level becomes the threshold value T1, the other subframe is also displayed. At the same time, the brightness level is filled, but the difference is that the difference between the brightness levels distributed to both subframes is a value corresponding to a predetermined function. As the predetermined function, as shown in FIG. 68 (k), it may be considered that the difference between the gradation level or the luminance level distributed to both subframes also includes a constant value. In some cases, a predetermined coefficient is applied. A method for distributing the luminance level to both subframes is defined. Note that FIG. 69 (l) can be adapted to FIGS. 68 (e) and 68 (f).

  In FIG. 70 (m), regarding the response speed of the liquid crystal, when the liquid crystal response time when the display luminance increases and the liquid crystal response time when the display luminance decreases, the luminance level is distributed from either the previous or next subframe. If the liquid crystal response time when the brightness rises> the liquid crystal response time when the brightness falls, the brightness level is assigned first from the second subframe, and the liquid crystal response time when the brightness rises <brightness. In the case of the liquid crystal response time at the time of descending, the luminance level is allocated first from the first half subframe. This can be adapted to FIGS. 67 (d) to 68 (h).

  When this is adapted to FIG. 67 (d), when the liquid crystal response time at the time of increasing the luminance> the liquid crystal response time at the time of decreasing the luminance, the luminance level assumed by the input image signal from the latter half (right side) of the two subframes. (Dot part). At this time, the gradation level of the input image signal <the threshold value T. When the second half of the subframe is full (shaded portion; threshold T), the luminance level assumed by the input image signal is assigned to the first half (left side) subframe (dot portion). At this time, the threshold value T <the gradation level of the input image signal. Further, when the liquid crystal response time when the luminance is increased <the liquid crystal response time when the luminance is decreased, the luminance level assumed by the input image signal is distributed from the first half (left side) of the two subframes (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When the first half subframe is full (shaded portion; threshold T), the luminance level assumed by the input image signal is assigned to the second half (right side) subframe (dot portion). At this time, the threshold value T <the gradation level of the input image signal.

  In FIG. 70 (n), the maximum display luminance level is Lmax, the minimum display luminance level is Lmin, and the response time when switching between the display luminance level Lmin state and the display luminance level Lmax state is about The response time from Lmin to Lmax (when the brightness is increased)> the response time from Lmax to Lmin (when the brightness is decreased) is determined as to which of the sub-frames the luminance level is less harmful. In this case, the luminance level is assigned first from the second half sub-frame, and when the response time from Lmin to Lmax <response time from Lmax to Lmin, the luminance level is assigned first from the first sub-frame. This can be adapted to FIGS. 67 (d) to 68 (h).

  FIG. 70 (o) shows a case where the upper limit value L of the gradation level corresponding to the distribution luminance level assigned to the subframe is set. This can be adapted to FIGS. 67 (a) to 68 (h).

  That is, for example, as in the case of FIG. 67D, the luminance when one frame is divided into two subframes and the luminance level assumed by the input image signal is sequentially distributed to each subframe. When the threshold value T is set as the reference value of the gradation level corresponding to the level, the luminance level assumed by the input image signal is distributed from one of the two subframes (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When the gradation level corresponding to the distribution luminance level of one of the subframes reaches the upper limit L (shaded portion; threshold T), the luminance level assumed by the input image signal is allocated to the other subframe (dot portion) ). At this time, the threshold value T <the gradation level of the input image signal.

  In FIG. 70 (p), upper limit values L1 to L3 are set to the gradation levels corresponding to the distribution luminance levels assigned to the subframes, and the upper limit values L1 to L3 are set to the time of one frame period in which image display is performed. This is a case where the center or the subframe closest to the center is set higher. This can be adapted to FIGS. 67 (a) to 67 (c).

  That is, for example, as in the case of FIG. 67B, when one frame is divided into three or more odd (here, for example, five) subframes, the temporal center of one frame period in which image display is performed. The luminance level assumed by the input image signal is distributed from the subframe (for example, the third from the left) (dot portion). At this time, the gradation level of the input image signal <the threshold value T1. When the gradation level corresponding to the distribution luminance level of the central sub-frame reaches the highest upper limit L1 (shaded portion; threshold value T1), an input image signal is assumed simultaneously in the left and right sub-frames of the central sub-frame. The brightness level is sorted (dot part). At this time, threshold value T1 <tone level of input image signal <threshold value T2. Further, when the gradation level corresponding to the distribution luminance level of the two left and right sub-frames reaches the next highest upper limit L2 (shaded portion; threshold T2), the left and right sub-frames are simultaneously transmitted to the left and right sub-frames simultaneously. The luminance level assumed by the input image signal is distributed to the lowest upper limit L3 (dot portion). At this time, the threshold value T2 <the gradation level of the input image signal. The upper limit value L3 <the upper limit value L2 <the upper limit value L1.

  In FIG. 71 (q), the upper limit values L1 and L2 for assigning the luminance levels assumed by the input image signal to the two subframes are set such that the upper limit value L1 is larger than the upper limit value L2. This can be adapted to FIGS. 67 (d) to 68 (h).

That is, for example, as in the case of FIG. 67D, the luminance when one frame is divided into two subframes and the luminance level assumed by the input image signal is sequentially distributed to each subframe. When the threshold value T is set as the reference value of the gradation level corresponding to the level, the luminance level assumed by the input image signal is distributed from one of the two subframes (dot portion). At this time, the gradation level of the input image signal <the threshold value T. When the gradation level corresponding to the distribution luminance level of one of the sub-frames is a high upper limit L1 (shaded portion; threshold T), the luminance level assumed by the input image signal in the other sub-frame is set to a lower upper limit. Sort to L2 (dot portion). At this time, the threshold value T <the gradation level of the input image signal. Low upper limit value L2 <high upper limit value L1.

  By providing the upper limit value L as shown in FIGS. 70 (o) to 71 (q) above, even when the gradation level of the input image signal is maximum, the luminance level of all subframes is 100%. In other words, the impulse effect can be obtained in the same manner as when black is inserted. If the upper limit is higher in the temporal central part, the luminance center of gravity becomes the central part.

  FIG. 71 (r) is the same as FIG. 67 (a), but here, the luminance level assumed for the input image signal and the time integral value of the display luminance show appropriate gamma luminance characteristics. In this case, the luminance level in each subframe period is set.

  That is, although the number of subframes to which the luminance level is distributed increases or decreases according to the gradation level of the input image signal, the time integration value of the luminance within one frame period always becomes the gradation level of the input image signal. On the other hand, a luminance level to be distributed to each subframe is determined so as to show an appropriate gamma luminance characteristic, and a gradation level for realizing the luminance level is set.

  In FIG. 71 (s), in addition to the contents of FIG. 71 (r), the time integral value of the luminance within one frame period always shows an appropriate gamma luminance characteristic with respect to the gradation level of the input image signal. As described above, the threshold of the gradation level, which serves as a reference for luminance level distribution to each subframe, is also determined.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-12 of this invention, this invention should not be limited and limited to this Embodiment 1-12. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range from the description of specific preferred embodiments 1 to 12 of the present invention based on the description of the present invention and the common general technical knowledge. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  For example, in the field of image display devices using a hold-type display element such as a liquid crystal display element or an EL display element, the temporal center of gravity position of the display luminance is determined by the gradation level of the input image signal while suppressing a decrease in maximum luminance and contrast. While minimizing image quality degradation due to differences, and ensuring compatibility of gradation representation for image signal input created on the premise of output to an image display device having general gamma luminance characteristics, It can improve the degradation of video quality called afterimage and motion blur.

It is a block diagram which shows the basic composition in Embodiment 1-8 of the image display apparatus of this invention. FIG. 2 is a block diagram illustrating a first embodiment of the controller LSI of FIG. 1. It is a figure which shows the flow of the image signal for every horizontal period in the image display apparatus of Embodiment 1 of this invention. It is a figure which shows a mode that the image signal on a screen is rewritten by repeating display control as shown in FIG. It is a figure which shows the change of the gradation level in the input image signal at the time of using a predetermined | prescribed display panel. When the gradation level of the input image signal changes as shown in FIG. 5, the change in display luminance on the display panel when subframe α period is assigned to the first half subframe and subframe β period is assigned to the second half subframe. It is a figure which shows a mode. When the gradation level of the input image signal changes as shown in FIG. 5, the change in display luminance on the display panel when the subframe β period is assigned to the first half subframe and the subframe α period is assigned to the second half subframe. It is a figure which shows a mode. It is a figure for demonstrating the target setting of the display luminance value in this Embodiment 1. FIG. FIG. 5 is a diagram illustrating a relationship between a gradation level of an input image signal satisfying the relationship of Expression 2 and a gradation level supplied in the first half and second half subframe periods in the image display apparatus according to the first embodiment. In the image display apparatus of Embodiment 1, when displaying an image in which an object moves horizontally on a stationary background, it is a diagram illustrating a state of a luminance change over time on one horizontal line in the screen. is there. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 10 is displayed. In the image display apparatus of Embodiment 1 of this invention, it is a figure which shows the difference of the response change of the display brightness by temperature conditions, when the gradation level of the image signal supplied to a display panel is not adjusted with temperature conditions. In the image display apparatus of Embodiment 1 of this invention, it is a figure which shows the response change of the display brightness by temperature conditions about the case where the gradation level of the image signal supplied to a display panel is adjusted with temperature conditions. In the image display apparatus of Embodiment 1 of this invention, it is a figure which shows the state in which the assumed brightness | luminance of an input image signal is changing in steps. It is a figure which shows the change of the display brightness | luminance when the image which changes in steps of FIG. 14 displays the image | video which moves to a horizontal direction. FIG. 16 is a diagram illustrating a distribution of brightness that is viewed by an observer watching a moving object when an image as illustrated in FIG. 15 is displayed. It is a figure for demonstrating the target setting of the display luminance value in this Embodiment 2. FIG. FIG. 10 is a diagram illustrating a relationship between a gradation level of an input image signal satisfying the relationship of Expression 2 and a gradation level supplied in the first half and second half subframe periods in the image display apparatus according to the second embodiment. In the image display apparatus of this Embodiment 2, it is a figure which shows the mode of the brightness | luminance change with time progress on one horizontal line in a screen, when displaying the image | video which an object moves horizontally on a stationary background. is there. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 19 is displayed. It is a figure for demonstrating the target setting of the display brightness value in this Embodiment 3. FIG. In the image display apparatus of Embodiment 3, it is a figure which shows the relationship between the gradation level of the input image signal which satisfy | fills the relationship of Formula 2, and the gradation level supplied in the first half and second half sub-frame period. In the image display apparatus of this Embodiment 3, it is a figure which shows the mode of the brightness | luminance change with time passage on one horizontal line in a screen, when displaying the image | video which an object moves horizontally on a still background. is there. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 23 is displayed. It is a figure for demonstrating the target setting of the display luminance value in this Embodiment 4. FIG. It is a figure which shows the relationship between the gradation level of the input image signal which satisfy | fills the relationship of said Formula 2, and the gradation level supplied in the first half and second half sub-frame period. In the image display device of Embodiment 4 of the present invention, in the case of displaying an object that moves horizontally on a stationary background, the luminance change (time change in screen luminance) over time on one horizontal line in the screen. It is a figure which shows a mode. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 27 is displayed. In the image display apparatus of Embodiment 4 of this invention, it is a figure which shows the difference of the response change of the display brightness by temperature conditions about the case where the gradation level of the image signal supplied to a display panel is not adjusted with temperature conditions. In the image display apparatus of Embodiment 4 of this invention, it is a figure which shows the response change of the display brightness by temperature conditions about the case where the gradation level of the image signal supplied to a display panel is adjusted with temperature conditions. In the image display device according to the fifth embodiment of the present invention, when displaying an object with a color in which red is strong and green and blue are weak on a black background, the time in each pixel unit on one horizontal line is displayed. It is a figure which shows the display state (time change of screen luminance) for every progress. In the image display device of another configuration example according to the fifth embodiment of the present invention, in the case of displaying an object with a color in which red is strong and green and blue are weak on a black background, one horizontal line is displayed. It is a figure which shows the display state (time change of screen luminance) for every time passage in each pixel part. FIG. 10 is a block diagram illustrating a main configuration of a controller LSI of FIG. 1 according to a sixth embodiment. It is a figure which shows the flow of the image signal for every frame period in the image display apparatus of Embodiment 6 of this invention. It is a figure which shows a mode that the image signal on a screen is rewritten in the image display apparatus of Embodiment 6 of this invention. In the image display device according to the sixth embodiment of the present invention, in the case of displaying an object that moves horizontally on a stationary background, the luminance change (time change in screen luminance) over time on one horizontal line in the screen. It is a figure which shows a mode. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 36 is displayed. FIG. 10 is a block diagram illustrating a main configuration of a controller LSI of FIG. 1 according to a seventh embodiment. In the image display device according to the seventh embodiment of the present invention, in the case of displaying an object that moves horizontally on a stationary background, the luminance change (time change in screen luminance) over time on one horizontal line in the screen. It is a figure which shows a mode. It is a figure which shows what kind of brightness distribution it looks for the observer who watched the moving object when the image | video like FIG. 39 is displayed. FIG. 10 is a block diagram illustrating a configuration of main parts of an embodiment 8 of the controller LSI of FIG. It is a figure which shows the flow of the image signal for every horizontal period in the image display apparatus of Embodiment 8 of this invention. It is a figure which shows a mode that a screen display is rewritten in the image display apparatus of Embodiment 8 of this invention. It is a figure which shows the time change of a screen brightness | luminance about the case where the object which moves horizontally on the stationary background is displayed in the image display apparatus of Embodiment 8 of this invention. It is a figure which shows distribution of the brightness perceived by an observer about the case where the object which moves horizontally on the stationary background is displayed in the image display apparatus of Embodiment 8 of this invention. In a conventional impulse type image display device, when displaying an image in which an object moves horizontally on a stationary background, it is a diagram showing a state of luminance change with time on one horizontal line in the screen. . FIG. 47 is a diagram showing how the brightness distribution looks for an observer who is gazing at a moving object when an image as shown in FIG. 46 is displayed. In a general conventional hold-type image display device, when displaying an image in which an object moves in a horizontal direction on a stationary background, the state of luminance change over time on one horizontal line in the screen is shown. FIG. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 48 is displayed. In a hold-type image display device adopting the black insertion method, when displaying an image in which an object moves horizontally on a stationary background, the change in luminance over time on one horizontal line in the screen is shown. FIG. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 50 is displayed. In the conventional hold-type image display device disclosed in Patent Document 1, when displaying an image in which an object moves horizontally on a stationary background, the luminance with the passage of time on one horizontal line in the screen It is a figure which shows the mode of a change. It is a figure which shows what kind of brightness distribution it looks for the observer who stared at the moving object when the image | video like FIG. 52 is displayed. The relationship between the display level and the gradation level assuming a conventional image signal created on the basis of the gamma luminance characteristics of the CRT is shown, and a conventional hold-type image display panel compatible with this image signal is shown. It is a figure which shows the relationship between the gradation level of an image signal, and display luminance. It is a figure which shows the relationship between the gradation level of an image signal, and display luminance about the case where the image display apparatus proposed by patent document 1 (7th Embodiment) is comprised using the conventional hold type display panel. . In a general hold type display device, it is a diagram showing a state of luminance change over time on one horizontal line on a screen when the above-described video is input. When an image is displayed as shown in FIG. 56, it is a figure which shows what brightness distribution is seen by the observer who watched the moving object. In the image display device of Embodiment 1, it is a diagram showing a state of a luminance change with the passage of time on one horizontal line on the screen when the video as described above is input. FIG. It is a figure which shows what kind of brightness distribution is seen by the observer who stared at the moving object when an image is displayed like FIG. It is a block diagram which shows the basic structural example in Embodiment 9 of the image display apparatus of this invention. FIG. 61 is a block diagram illustrating a configuration example of a controller LSI of FIG. 60. FIG. 6 is a diagram showing six examples with different target luminance levels among the relationship between the gradation level of the input image signal shown in Table 2, the gradation levels of the first half and the second half subframe, and the perceived brightness. It is a graph which shows the relationship between the gradation level of the input image at the time of using the look-up tables AC of Table 2-Table 4, and the value [perceived brightness] time-integrated in 1 frame period. It is a block diagram which shows the structural example in case the image display control means of the image display apparatus of this Embodiment 10 processes by a computer. It is a block diagram which shows the structural example in Embodiment 11 of the liquid crystal television apparatus using the image display apparatus of this invention. It is a block diagram which shows the structural example in Embodiment 12 of the liquid crystal monitor device using the image display apparatus of this invention. (A)-(d) demonstrates the example (the 1) of the various distribution methods which distribute the luminance level which the input image signal to an image display part assumes in each sub-frame period in the image display apparatus of this invention. It is a conceptual diagram of each sub-frame for doing. (E) to (h) illustrate examples (part 2) of various distribution methods for distributing the luminance level assumed by the input image signal to the image display unit in each subframe period in the image display device of the present invention. It is a conceptual diagram of each sub-frame for doing. (I) to (l) illustrate examples (part 3) of various distribution methods for distributing the luminance levels assumed by the input image signal to the image display unit in each subframe period in the image display device of the present invention. It is a conceptual diagram of each sub-frame for doing. (M) to (p) illustrate examples (part 4) of various distribution methods for distributing the luminance levels assumed by the input image signal to the image display unit in each subframe period in the image display device of the present invention. It is a conceptual diagram of each sub-frame for doing. (Q) to (s) illustrate examples (No. 5) of various distribution methods for distributing the luminance level assumed by the input image signal to the image display unit in each subframe period in the image display device of the present invention. It is a conceptual diagram of each sub-frame for doing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 10 Display panel 11a Display element 12 TFT substrate 11 Display element array 12a Pixel electrode 12b TFT
13a to 13d, 13Da to 13Dd Source driver 14a to 14d Gate driver 20 Temperature sensor IC
21 Gamma luminance characteristic setting switch 30 Frame memory 40, 40A to 40F Controller LSI (display control means)
41 line buffer 41a single line buffer 42 timing controller 43 frame memory data selector 44 first gradation conversion circuit 45 second gradation conversion circuit 46 output data selector 47 first multiline buffer 48 second multiline buffer 49 buffer data selector 50 Intermediate image generation circuit 51 Gradation level averaging circuit 52 Gradation conversion source selector 401 Control means 402 ROM
403 RAM
1000 Liquid crystal television apparatus 1001 Tuner section 2000 Liquid crystal monitor apparatus 2001 Signal processing section T101 1 frame period T201 First half subframe period T202 Second half subframe period T301 First subframe period T302 Second subframe period T303 Third subframe period A Still Display section for background B Moving object display section B1, C Luminance value

Claims (78)

One frame period is divided into a plurality of subframe periods including a first subframe, a second subframe,..., An nth (n is an integer of 3 or more) subframe, and the gray level of the input image signal is obtained. Accordingly, in the image display device that determines the gradation level of each sub-frame and supplies it to the image display unit to display the image,
Subframes in the temporal center of the one-frame period (when n is an odd number of 3 or more), or subframes positioned before and after the temporal center (when n is an even number of 4 or more) Display control means for supplying a tone level, the display control means comprising:
The relationship between the gradation level of the input image signal and the time integration amount of the display luminance in the one frame period is increased / decreased according to the input image signal so as to show the gamma luminance characteristic, and is supplied to each subframe period. Display device for setting a gradation level of an image signal to be processed.   The display control means minimizes the gradation level of all subframes when the gradation level of the input image signal is minimum, and all subframes when the gradation level of the input image signal is maximum. The image display apparatus according to claim 1, wherein the gradation level is maximized.   The display control means controls the gradation level output in each subframe so that an integral value of display luminance corresponding to the input image signal in the one frame period indicates the gamma luminance characteristic, and the image The image display device according to claim 1, wherein an image is displayed on the display unit. The first subframe, the second subframe,..., 1 depending on the total amount of time integration of luminance displayed on the image display unit in n subframe periods consisting of nth (n is an integer of 3 or more) subframes. An image display device that displays an image during a frame period,
Display control means for performing image display control of n subframe periods for the image display unit for each one frame period, the display control means,
The relationship between the gradation level of the input image signal and the time integration amount of the display luminance in the one frame period is increased or decreased in accordance with the input image signal so as to show the gamma luminance characteristics. When setting the gradation level of the image signal supplied during the period,
Subframe period at the center of one frame period in which image display is performed (when n is an odd number of 3 or more), or subframe period positioned before and after the center (when n is an even number of 4 or more) In this case, the image signal having the maximum gradation level in the range in which the total amount of time integration of the luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal. Supplied to the image display,
When the total amount of time integration of luminance displayed in the center or the subframe period closest to the center does not reach the luminance corresponding to the gradation level of the input image signal, In a subframe period before and after a near subframe period, a range in which the total amount of time integration of luminance displayed in the n subframe periods does not exceed a luminance level corresponding to the gradation level of the input image signal To supply the image signal of the maximum gradation level to the image display unit,
When the total amount of time integration of luminance displayed in the center or the subframe period closest to the center and the subframe periods before and after the center does not reach the luminance corresponding to the gradation level of the input image signal, Further, in the preceding and succeeding subframe periods, the total amount of time integration of luminance displayed in the n subframe periods is the maximum within a range not exceeding the luminance level corresponding to the gradation level of the input image signal. In the control for supplying the image signal of the gradation level to the image display unit, the total amount of time integration of luminance corresponding to the gradation level of all the supplied image signals corresponds to the gradation level of the input image signal. An image display device that repeatedly supplies the image display unit with an image signal having a gradation level that is minimum or smaller than a predetermined value in the remaining subframe period. An image display device that displays an image for one frame period by a total amount of time integration of luminance displayed on the image display unit in n (n is an odd number of 3 or more) subframe period,
Display control means for performing image display control of n subframe periods for the image display unit for each one frame period, the display control means,
Image display is performed in n subframe periods including a first subframe, a second subframe,..., An nth subframe in order from the earliest in time or in order from the latest. The m-th subframe period that is the temporal center of the frame period is set by m = (n + 1) / 2,
When (n + 1) / 2 threshold values are set to T1, T2,..., T [(n + 1) / 2] in ascending order of values with respect to the gradation level of the image signal,
When the gradation level of the input image signal is equal to or lower than the threshold value T1, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal is displayed in the mth subframe period. Supply to the display unit, and supply the image signal of the gradation level smaller than the minimum or a predetermined value to the image display unit in the other subframe period,
When the gradation level of the input image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the image display unit displays an image signal having a gradation level that is maximum or greater than a predetermined value in the m-th subframe period. In the (m-1) th subframe period and the (m + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the others. In the sub-frame period, an image signal having a gradation level smaller than the minimum or a predetermined value is supplied to the image display unit,
When the gradation level of the input image signal is greater than the threshold value T2 and equal to or less than the threshold value T3, the maximum or the minimum in the m-th subframe period, the m−1th subframe period, and the m + 1th subframe period An image signal having a gradation level larger than a predetermined value is supplied to the image display unit, and the level is increased or decreased according to the gradation level of the input image signal in the (m-2) th subframe period and the (m + 2) th subframe period. An image signal of a tone level is supplied to the image display unit, and an image signal of a gradation level smaller than a minimum value or a predetermined value is supplied to the image display unit in other subframe periods,
Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx−1 (x is an integer of 4 or more) and equal to or smaller than the threshold value Tx, the [m− (x−2)] th subframe. In each subframe period from the period to the [m + (x−2)] th subframe period, an image signal having a maximum gradation level or greater than a predetermined value is supplied to the image display unit, and the [m− (x−1) th )] In the subframe period and the [m + (x−1)] th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. In the other sub-frame period, an image signal having a gradation level smaller than a minimum value or a predetermined value is supplied to the image display unit,
An image display device in which the length of the m-th subframe period is set to be longer than the lengths of other subframe periods. An image display device that performs image display for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods,
One subframe period is a subframe α period, the other subframe is a subframe β period,
Display control means for performing image display control of the two subframe periods for the image display unit for each frame period, the display control means,
When the gradation level of the input image signal is equal to or less than a uniquely determined threshold, the gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period. An image signal is supplied to the image display unit, and an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit in the subframe β period,
When the gradation level of the input image signal is larger than the threshold value, an image signal having a gradation level that is maximum or larger than a predetermined value in the subframe α period is supplied to the image display unit, and the subframe β period In the method, an image signal having a gradation level that is increased or decreased according to the input image signal is supplied to the image display unit.
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. An image display device that performs image display for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods,
Display control means for performing image display control of the two subframe periods for the image display unit for each one frame period;
One subframe period is a subframe α period, and the other subframe is a subframe β period. Two gradation level thresholds T1 and T2 are determined, and the threshold T2 is larger than the threshold T1. The display control means
When the gradation level of the input image signal is equal to or less than the threshold value T1, the image display unit displays the gradation level image signal that is increased or decreased according to the gradation level of the input image signal in the subframe α period. In the subframe β period, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit,
When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period. Is supplied to the image display unit, and in the subframe β period, the gradation is lower than the gradation level supplied in the subframe α period, and is increased or decreased according to the gradation level of the input image signal. Level image signal to the image display unit,
When the gradation level of the input image signal is larger than the threshold value T2, an image signal having a gradation level that is maximum or larger than a predetermined value is supplied to the image display unit in the subframe α period, and in the subframe β period. Is to supply an image signal of a gradation level that is increased or decreased according to the input image signal to the image display unit,
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. An image display device that performs image display for one frame period by the total amount of time integration of luminance displayed on the image display unit in two subframe periods,
One subframe period is a subframe α period, the other subframe is a subframe β period,
Display control means for performing image display control of the two subframe periods for the image display unit for each frame period, the display control means,
Estimate and generate a temporally intermediate frame image for two consecutively input images,
In the subframe α period, when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold, the gradation level that is increased or decreased according to the gradation level of the input image signal An image signal is supplied to the image display unit, and when the gradation level of the input image signal is larger than the threshold value, an image signal having a maximum or larger gradation level is supplied to the image display unit,
In the subframe β period, when the gradation level of the image signal in the intermediate frame image is equal to or lower than the threshold value, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit, and When the gradation level in the intermediate state frame image is larger than the threshold value, the gradation level image signal that is increased or decreased according to the gradation level of the image signal in the intermediate state frame image is displayed in the image. To supply
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. The image display device according to claim 1 , wherein the period lengths of the subframes are the same or different from each other.   The length of the subframe period of the temporal center of the one frame period or the subframe period of the subframe located before and after the temporal center is set to be longer than the length of the other subframe period. The image display device according to claim 1. The gradation level supplied in the subframe α period and the gradation level supplied in the subframe β period when the gradation level of the input image signal is larger than the threshold value T1 and equal to or less than the threshold value T2,
The difference between the gradation level of the subframe α period and the gradation level of the subframe β period is a constant value, or the luminance level of the subframe α period and the luminance level of the subframe β period The image display device according to claim 7, wherein the difference is set to be a constant value. The gradation level supplied in the subframe α period and the gradation level supplied in the subframe β period when the gradation level of the input image signal is larger than the threshold value T1 and equal to or less than the threshold value T2,
The relationship between the gradation level of the subframe α period and the gradation level of the subframe β period is set by one function, or the luminance level of the subframe α period and the luminance level of the subframe β period The image display device according to claim 7, wherein the relationship is set so as to be set by a single function. In the image display unit, the maximum display luminance level is Lmax, the minimum display luminance level is Lmin, and the display luminance is compared with the response time when switching from the display luminance level Lmin to the display luminance level Lmax. When the response time when switching from the level Lmax state to the display luminance level Lmin state is short, the subframe α period is set as the second subframe of the one frame period, and when this is long, the subframe is the image display apparatus according to any one of claims 6-8 for the α period and the first half of the sub-frames in the one frame period. Wherein the display control unit, an image display apparatus according to any one of claims 1 to 8, the upper limit value with respect to the gradation level of the image signal supplied in each sub frame period is set. The display control means includes
L1, L2,..., Ln are the upper limit values for the gradation levels of the image signals supplied in the first subframe period, the second subframe period,.
Of the n subframe periods, the temporal center of one frame period in which image display is performed or the subframe period closest to the center is the jth subframe period, and i is an integer between 0 and less than j. If
L [j−i] ≧ L [j− (i + 1)],
L [j + i] ≧ L [j + (i + 1)],
The image display device according to claim 1, wherein an upper limit value is set for an image signal of a gradation level supplied in each subframe period so as to satisfy the relationship. The display control means includes
Each subframe period so as to satisfy the relationship of the upper limit value L1 for the gradation level of the image signal supplied in the one subframe period ≧ the upper limit value L2 of the gradation level of the image signal supplied in the other subframe period the image display apparatus according to any one of claims 6-8 in which the upper limit is set for the gradation level image signals with respect to. The display control means includes
The relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period is a criterion for determining the gradation level of the image signal in each subframe period so as to show the gamma luminance characteristic. threshold and, the image display apparatus according to any one of claims 5-8 to set the tone level is increased or decreased in accordance with an image signal inputted image signal supplied to each sub frame period. It further comprises temperature detecting means for detecting the panel temperature or its surrounding temperature,
2. The display control unit sets a gradation level of an image signal that is increased / decreased according to an input image signal and supplied in each subframe period according to the temperature detected by the temperature detection unit. Or the image display apparatus of 4. It further comprises temperature detecting means for detecting the panel temperature or its surrounding temperature,
In accordance with the temperature detected by the temperature detection means, the display control means is increased / decreased according to a threshold value that is a criterion for determining the gradation level of the image signal in each subframe period, and according to the input image signal. the image display apparatus according to any one of claims 5-8 for setting the gradation level of the image signal supplied to the sub-frame periods. When the input image signal is composed of image signals of a plurality of color components,
The display control means includes
The ratio between the luminances displayed for each subframe period for the color components other than the color component having the highest gradation level of the input image signal is the highest in the gradation level of the input image signal. to be the same as the ratio between the luminance to be displayed respectively in each sub-frame periods for the color components, one of claims 1-8 to set the tone level of the image signal supplied in each sub frame period The image display device described in 1. The display control means includes
Timing control means;
Line data storage means for temporarily receiving an image signal for one horizontal line;
Frame storage data selection which is controlled by the timing control means to switch whether to transfer data from the line data storage means to the frame data storage means or to output data one frame before read from the frame data storage means Means,
A gradation level of an image signal supplied from the line data storage means is converted into a gradation level that is increased or decreased in accordance with a gradation level that is maximum or larger than a predetermined value or a gradation level of an input image signal. Gradation conversion means;
The gradation level of the image signal supplied from the frame storage data selection means is converted into a gradation level that is increased or decreased according to the minimum or smaller gradation level or the gradation level of the input image signal. Two gradation conversion means;
Output data selection controlled by the timing control means to switch between the image signal output from the first gradation conversion means and the image signal output from the second gradation conversion means to be supplied to the image display unit the image display apparatus according to any one of claims 6-8, which comprises a means. The display control means includes
Timing control means;
Line data storage means for temporarily receiving an image signal for one horizontal line;
A first plurality of line data storage means and a second plurality of line data storage means for temporarily holding image signals for a plurality of horizontal lines;
Controlled by the timing control means, the data is transferred from the line data storage means to the frame data storage means, or the image data of one frame before read from the frame data storage means is stored in the first plural line data storage Frame storage data selection means for switching to transfer the image data of the previous two frames read from the frame data storage means to the second multi-line data storage means,
Intermediate image generation means for estimating and generating temporally intermediate frame image data for the two frames of image data supplied from the first multiple line data storage means and the second multiple line data storage means;
Image data supplied from the first plurality of line data storage means and temporary storage data selection means for switching and outputting the image data supplied from the second plurality of line data storage means, controlled by the timing control means; ,
The gradation level of the image signal supplied from the temporarily stored data selection means is converted into a gradation level that is increased or decreased according to the maximum or larger gradation level or the gradation level of the input image signal. One gradation conversion means;
A second level for converting the gradation level of the image signal supplied from the intermediate image generating means to a gradation level that is minimum or smaller than a predetermined value or that is increased or decreased in accordance with the gradation level of the input image signal. Gradation conversion means;
Output data selection means that is controlled by the timing control means to switch between an image signal output from the first gradation conversion means and an image signal output from the second gradation conversion means and supplies the image signal to the image display unit An image display device according to claim 8 . The gradation level larger than the predetermined value is a gradation level larger than 90% when the maximum is 100%, and the gradation level smaller than the predetermined value is smaller than 10% when the minimum is 0%. The image display device according to any one of claims 4 to 8, 21 and 22 , which has a gradation level. The gradation level larger than the predetermined value is a gradation level corresponding to a luminance level larger than 90% when the maximum luminance level is 100%, and the gradation level smaller than the predetermined value has a minimum luminance level of 0. The image display device according to any one of claims 4 to 8, 21 and 22 , which has a gradation level corresponding to a luminance level smaller than 10 percent when the percentage is used. The gradation level larger than the predetermined value is a gradation level larger than 98% when the maximum is 100%, and the gradation level smaller than the predetermined value is smaller than 2% when the minimum is 0%. The image display device according to any one of claims 4 to 8, 21 and 22 , which has a gradation level. The gradation level larger than the predetermined value is a gradation level corresponding to a luminance level larger than 98% when the maximum luminance level is 100%, and the gradation level smaller than the predetermined value has a minimum luminance level of 0. The image display device according to any one of claims 4 to 8, 21 and 22 , which has a gradation level corresponding to a luminance level smaller than 2 percent when the percentage is used. A gamma luminance characteristic setting means for enabling the gamma luminance characteristic to be set from outside;
The image display device according to claim 17 , wherein the display control unit can change the gamma luminance characteristic set from the outside by the gamma luminance characteristic setting unit.   6. When the plurality of sub-frame periods are three or more sub-frame periods, the gradation level that is sequentially distributed is higher in the central part than the end part in the one-frame period. The image display device described in 1.   When the plurality of subframe periods are three or more subframe periods, the luminance levels of the sequentially assigned subframe images are higher in the center than in the end in the one frame period. The image display device according to any one of 5.   6. The image display device according to claim 1, wherein a change in the center of gravity of time integral of luminance displayed in the plurality of subframe periods is within one subframe period. Wherein the display control unit, an image display apparatus according to any one of claims 1 to 23 for display control for each of the pixel portions on a display screen. 32. The image display device according to claim 31 , wherein the pixel portion has one pixel or a predetermined number of pixels. An electronic apparatus that displays an image on a display screen of a display unit using the image display device according to any one of claims 1 to 32 . And an image display device according to any one of claims 1-32, the display control unit of the image display device, a liquid crystal television device and a tuner section which allows outputs a television broadcast signal to select a channel. 33. The image display device according to any one of claims 1 to 32 , and a signal processing unit capable of outputting a monitor image signal obtained by processing an external monitor signal to the display control means of the image display device. LCD monitor device. An image display method using an image display device that displays an image for one frame period by a total amount of time integration of luminance displayed on an image display unit in n (n is an integer of 5 or more) subframe periods,
The relationship between the gradation level of the input image signal and the time integration amount of the display luminance in the one frame period is increased or decreased in accordance with the input image signal so as to show the gamma luminance characteristics. It sets the gradation level of the image signal supplied during the period,
At the temporal center of one frame period in which image display is performed or the subframe period closest to the center, the total amount of time integration of luminance displayed in the n subframe periods is the scale of the input image signal. A process of supplying an image signal having the maximum gradation level to the image display unit within a range not exceeding the luminance level corresponding to the gradation level;
When the total amount of time integration of luminance displayed in the center or the subframe period closest to the center does not reach the luminance corresponding to the gradation level of the input image signal, the center or the sub-closest to the center In the subframe periods before and after the frame period, the total amount of time integration of luminance displayed in the n subframe periods is maximum within a range not exceeding the luminance level corresponding to the gradation level of the input image signal. A process of supplying an image signal of the gradation level to the image display unit;
When the total amount of time integration of luminance displayed in the center or the subframe period closest to the center and the subframe periods before and after the center does not reach the luminance corresponding to the gradation level of the input image signal, In the preceding and succeeding subframe periods, the maximum level in the range in which the total amount of time integration of luminance displayed in the n subframe periods does not exceed the luminance level corresponding to the gradation level of the input image signal. In the control for supplying the tone level image signal to the image display unit, the total amount of time integration of the luminance corresponding to the tone levels of all the supplied image signals corresponds to the tone level of the input image signal. Processing to supply the image display unit with an image signal having a gradation level that is minimum or smaller than a predetermined value in the remaining subframe period. Image display method. An image display method using an image display device that displays an image for one frame period by a total amount of time integration of luminance displayed on an image display unit in n (n is an odd number of 3 or more) subframe period,
Image display is performed in n subframe periods including a first subframe, a second subframe,..., An nth subframe in order from the earliest in time or in order from the latest. The m-th subframe period that is the temporal center of the frame period is set by m = (n + 1) / 2,
In the case where (n + 1) / 2 threshold values are set as T1, T2,..., T [(n + 1) / 2] in ascending order with respect to the gradation level of the image signal, When the length of the m-th subframe period is set to be longer than the length of other subframe periods,
When the gradation level of the input image signal is equal to or lower than the threshold value T1, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal is displayed in the mth subframe period. A process of supplying the image display unit with an image signal having a gradation level that is minimum or smaller than a predetermined value in the other subframe period,
When the gradation level of the input image signal is greater than the threshold value T1 and less than or equal to the threshold value T2, the image display unit displays an image signal having a gradation level that is maximum or greater than a predetermined value in the m-th subframe period. In the (m-1) th subframe period and the (m + 1) th subframe period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit, and the others. A process of supplying an image signal having a gradation level smaller than or smaller than a predetermined value to the image display unit in the subframe period of
When the gradation level of the input image signal is larger than the threshold value T2 and equal to or smaller than the threshold value T3, the maximum or predetermined value is applied in the m-th subframe period, the m-1 subframe period, and the m + 1 subframe period. An image signal having a gradation level greater than the value is supplied to the image display unit, and the gradation is increased or decreased in accordance with the gradation level of the input image signal in the (m-2) th subframe period and the (m + 2) th subframe period. A process of supplying an image signal of a level to the image display unit, and supplying an image signal of a gradation level smaller than a minimum or a predetermined value to the image display unit in other subframe periods;
Thereafter, when the gradation level of the input image signal is larger than the threshold value Tx−1 (x is an integer of 4 or more) and equal to or smaller than the threshold value Tx, the [m− (x−2)] th subframe period. To the image display unit is supplied with an image signal having a maximum gradation level or greater than a predetermined value in each subframe period from the [m + (x-2)] th subframe period to the [m + (x-2)] th subframe period. In the sub-frame period and the [m + (x−1)]-th sub-frame period, an image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal is supplied to the image display unit. And a process of supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the image display unit in the subframe period. An image display method using an image display device that displays an image of one frame period by a total amount of time integration of luminance displayed on an image display unit in two subframe periods,
One subframe period is a subframe α period, the other subframe is a subframe β period,
An image with a gradation level that is increased or decreased in accordance with the gradation level of the input image signal during the subframe α period when the gradation level of the input image signal is equal to or less than a uniquely determined threshold value. A process of supplying a signal to the image display unit and supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the image display unit in the subframe β period;
When the gradation level of the input image signal is larger than the threshold value, an image signal having a gradation level that is maximum or larger than a predetermined value is supplied to the image display unit in the subframe α period, and in the subframe β period Includes a process of supplying an image signal of a gradation level that is increased or decreased according to an input image signal to the image display unit,
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. An image display method using an image display device that displays an image of one frame period by a total amount of time integration of luminance displayed on an image display unit in two subframe periods,
One subframe period is a subframe α period, and the other subframe is a subframe β period. Two gradation level thresholds T1 and T2 are determined, and the threshold T2 is larger than the threshold T1.
When the gradation level of the input image signal is equal to or less than the threshold value T1, the image signal of the gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period is input to the image display unit. A process of supplying an image signal having a gradation level that is minimum or smaller than a predetermined value to the image display unit in the subframe β period;
When the gradation level of the input image signal is greater than the threshold value T1 and equal to or less than the threshold value T2, the image signal having a gradation level that is increased or decreased according to the gradation level of the input image signal in the subframe α period. The gradation level that is supplied to the image display unit and is lower than the gradation level supplied in the subframe α period in the subframe β period, and is increased or decreased according to the gradation level of the input image signal A process of supplying the image signal to the image display unit;
When the gradation level of the input image signal is larger than the threshold value T2, the image signal having the maximum gradation level or larger than the predetermined value is supplied to the image display unit in the subframe α period, and in the subframe β period. And a process of supplying an image signal of a gradation level that is increased or decreased according to the input image signal to the image display unit,
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. An image display method using an image display device that displays an image of one frame period by a total amount of time integration of luminance displayed on an image display unit in two subframe periods,
One subframe period is a subframe α period, the other subframe is a subframe β period,
A process of estimating and generating a temporally intermediate frame image for two consecutively input images;
In the subframe α period, when the gradation level of the input image signal is equal to or lower than a uniquely determined threshold, the gradation level that is increased or decreased according to the gradation level of the input image signal A process of supplying an image signal to the image display unit, and supplying an image signal having a maximum or higher gradation level to the image display unit when the gradation level of the input image signal is larger than the threshold value; ,
In the subframe β period, when the gradation level of the image signal in the intermediate frame image is equal to or lower than the threshold value, an image signal having a gradation level that is minimum or smaller than a predetermined value is supplied to the image display unit, and When the gradation level in the image in the intermediate state is larger than the threshold value, the image display unit displays the image signal of the gradation level that is increased or decreased according to the gradation level of the image signal in the image in the intermediate state And processing to supply to
In the image display unit, when the response time when the display brightness decreases is shorter than the response time when the display brightness increases, the subframe α period is the latter half of the one frame period. If the subframe α is long, the subframe α period is the first half of the one frame period. The display control program for making a computer perform each process of the image display method in any one of Claims 36-40 . 42. A computer-readable recording medium on which the display control program according to claim 41 is recorded. The gradation level that is temporally distributed before and after the subframe period is smaller than the temporally divided gradation level by half or less than the temporally distributed gradation level. 2. The image display device according to 1. An image display method for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of 3 or more,
Supplying the gradation level of the input image signal to the image display unit,
Providing a maximum luminance value to at least one center of the plurality of subframes and supplying a minimum luminance level to a subframe farthest from the center of the plurality of subframes;
The relationship between the gradation level of the input image signal and the temporal integration amount of display luminance in one frame period is increased or decreased according to the input image signal and supplied to each subframe period so as to show the gamma luminance characteristic. An image display method for setting a gradation level of an image signal. 45. The image display method according to claim 44 , wherein when the gradation level is 50% or more of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central subframe. 46. The image display according to claim 45 , wherein if the gradation level is less than 50% of the maximum luminance level, a minimum luminance level is supplied to a subframe farthest from the center of the plurality of subframes. Method. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. The image display method according to claim 44, wherein the image display method is supplied to a central subframe. 45. The image display method according to claim 44, further comprising displaying the input image signal at the supplied gradation level. 49. A computer program for causing a computer to execute the image display method according to claim 44 . 50. A computer readable recording medium comprising the computer program of claim 49 . An image display method for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of 3 or more ,
Supplying the gradation level of the input image signal to the image display unit,
Lowering the luminance value of the gradation level from the center of the plurality of subframes to the outer subframe;
The relationship between the gradation level of the input image signal and the temporal integration amount of display luminance in one frame period is increased or decreased according to the input image signal and supplied to each subframe period so as to show the gamma luminance characteristic. An image display method for setting a gradation level of an image signal. When the gradation level is at least 50% of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central sub-frame of the plurality of sub-frames, according to claim 51 Image display method. When the gradation level is less than 50% of the maximum brightness level, the image display according to 請 Motomeko 52 the luminance level of the minimum value is supplied to the sub-frame farthest from the center of the plurality of sub-frame Method. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. 52. The image display method according to claim 51 , wherein the image display method is supplied to a central subframe. 52. The image display method according to claim 51 , further comprising displaying the input image signal at the supplied gradation level. The computer program for making a computer perform the image display method in any one of Claims 51-55 . 57. A computer-readable recording medium comprising the computer program of claim 56 . An image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of three or more,
Means for supplying a gradation level of an input image signal;
Display means for displaying the input image signal at the supplied gradation level;
Providing a maximum luminance value to at least one center of the plurality of subframes and supplying a minimum luminance level to a subframe farthest from the center of the plurality of subframes;
The relationship between the gradation level of the input image signal and the temporal integration amount of display luminance in one frame period is increased or decreased according to the input image signal and supplied to each subframe period so as to show the gamma luminance characteristic. An image display device for setting a gradation level of an image signal. When the gradation level is at least 50% of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central sub-frame of the plurality of sub-frames, according to claim 58 Image display device. 60. The image display of claim 59 , wherein a minimum luminance level is supplied to a subframe farthest from the center of the plurality of subframes when the gray level is less than 50% of the maximum luminance level. apparatus. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. 59. The image display device according to claim 58 , wherein the image display device is supplied to a central subframe. An image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of three or more,
A display controller configured to supply a gradation level of the input image signal;
An image display unit configured to display the image signal at the supplied gradation,
Providing a maximum luminance value to at least one center of the plurality of subframes and supplying a minimum luminance level to a subframe farthest from the center of the plurality of subframes;
The display control unit increases or decreases the relationship between the gradation level of the input image signal and the time integration amount of the display luminance in one frame period according to the input image signal so as to indicate the gamma luminance characteristic. An image display device for setting a gradation level of an image signal supplied in a subframe period. When the gradation level is at least 50% of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central sub-frame of the plurality of sub-frames, according to claim 62 Image display device. When the gradation level is less than 50% of the maximum brightness level, the image display according to 請 Motomeko 63 the luminance level of the minimum value is supplied to the sub-frame farthest from the center of the plurality of sub-frame apparatus. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. 64. The image display device according to claim 63 , which is supplied to a central sub-frame. An image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of three or more,
Means for supplying a gradation level of an input image signal;
Display means for displaying the input image signal at the supplied gradation level,
Lowering the luminance value of the gradation level from the center of the plurality of subframes to the outer subframe;
The relationship between the gradation level of the input image signal and the temporal integration amount of display luminance in one frame period is increased or decreased according to the input image signal and supplied to each subframe period so as to show the gamma luminance characteristic. An image display device for setting a gradation level of an image signal. When the gradation level is at least 50% of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central sub-frame of the plurality of sub-frames, according to claim 66 Image display device. 68. The image display of claim 67 , wherein if the gray level is less than 50% of the maximum luminance level, a minimum luminance level is provided in a subframe furthest away from the center of the plurality of subframes. apparatus. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. The image display device according to claim 66 , which is supplied to the central sub-frame. An image display device for supplying an image of an input image signal for display, wherein a frame period is divided into a plurality of subframe periods of three or more,
A display controller configured to supply a gradation level of the input image signal;
An image display unit configured to display the image signal at the supplied gradation,
The display control unit lowers the luminance value of the gradation level with respect to the subframes outside the center of the plurality of subframes, and adjusts the gradation level of the input image signal and the display luminance in one frame period. An image display device that sets a gradation level of an image signal supplied in each subframe period by increasing or decreasing in accordance with the input image signal so that a relationship with a time integration amount indicates a gamma luminance characteristic. When the gradation level is at least 50% of the maximum luminance level, the luminance level of the maximum luminance value is supplied to at least one central sub-frame of the plurality of sub-frames, according to claim 70 Image display device. 72. The image display of claim 71 , wherein a minimum luminance level is provided to a subframe farthest from the center of the plurality of subframes when the gray level is less than 50% of the maximum luminance level. apparatus. When the number of the plurality of subframes is an odd number, the maximum luminance value is supplied to at least one central subframe, and when the number of the plurality of subframes is an even number, the maximum luminance value is at least two. The image display device according to claim 70 , wherein the image display device is supplied to a central subframe. The computer program for making a computer perform the image display method in any one of Claims 37-40 . A computer-readable recording medium comprising the computer program according to claim 74 . An electronic device that displays an image on a display screen of a display unit using the image display device according to any one of claims 1, 4 to 8, 58, 62, 66, and 70 . An image display device according to any one of claims 4 to 8, 58, 62, 66 and 70 , and a tuner unit capable of outputting a television broadcast signal with a selected channel to display control means of the image display device; LCD television device with The image display device according to any one of claims 4 to 8, 58, 62, 66 and 70 , and a monitor image signal obtained by signal-processing an external monitor signal to the display control means of the image display device can be output. And a signal processing unit.