JP2005122201A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of realizing the improvement in general image quality by appropriately suppressing image quality deterioration by factors such as a motion blur, and stroboscopic and flicker phenomena. <P>SOLUTION: The liquid crystal display device which is provided with a display period and non-display period for an image signal to be displayed within a single frame period is equipped with: a means for displaying on screen an impulse rate setting screen for selecting the proportion of the display period of the image signal within the single frame period; and a means for variably controlling the ratio of the display period of the image signal within the single frame period on the basis of the selection instruction information of the impulse rate by a user. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device that displays an image by illuminating a liquid crystal display panel with a backlight light source, and more particularly to a liquid crystal display device that prevents motion blur that occurs when displaying a moving image by bringing it closer to an impulse-type display. is there.

  In recent years, flat panel display devices (FPD) such as liquid crystal display devices (LCD) that can realize high definition, low power consumption, and space saving have been actively developed, and in particular, computer display devices and television display devices. The spread of LCDs for such applications is remarkable. However, in contrast to a cathode ray tube (CRT) display device that has been mainly used for such applications, the LCD has a blurred outline of the moving part when a moving image is displayed. It has been pointed out the disadvantage of the so-called “motion blur” that it is perceived.

  It has been pointed out that the motion blur in moving image display is caused not only by the delay of the optical response time of the liquid crystal but also by the LCD display method itself as described in, for example, Japanese Patent Laid-Open No. 9-325715. In a CRT display device that scans an electron beam and emits phosphors to perform display, each pixel emits light almost in an impulse form although there is a slight afterglow of the phosphors. Yes.

  On the other hand, in the LCD display device, the charge stored by applying the electric field to the liquid crystal is held at a relatively high rate until the next electric field is applied (particularly in the TFT LCD, the pixel is configured. A TFT switch is provided for each dot to be operated, and since an auxiliary capacitor is usually provided for each pixel, the stored charge is very high in capacity), so that the liquid crystal pixel is based on the image information of the next frame. This is a so-called hold type display system in which light emission is continued until rewriting is performed by applying an electric field.

  In such a hold-type display device, since the impulse response of the image display light has a temporal spread, the temporal frequency characteristic is deteriorated, and the spatial frequency characteristic is also lowered accordingly, and the visual image is blurred. . Therefore, in the above-mentioned Japanese Patent Application Laid-Open No. 9-325715, display light is viewed only in the second half of each field period of a display image by controlling on / off of a shutter or a light source lamp (backlight) provided on the display surface. There has been proposed a display device that improves the motion blur of a viewing image by presenting to a person and limiting the temporal spread of the impulse response.

  This will be described with reference to FIGS. In FIG. 1, 111 is a light source lamp that can be turned on / off at high speed, such as a strobe lamp, 112 is a power source that supplies power to the light source lamp 111, and 113 is a TFT type that converts an electrical image signal into image display light. A transmissive display element such as a liquid crystal, 116 is a drive circuit for generating a drive signal for driving the display element 113 by an image signal and a synchronization signal, and 117 is a control pulse synchronized with the vertical synchronization of the input synchronization signal. This is a pulse generation circuit for generating and controlling on / off of the power source 112.

  When the lighting rate is 50% by supplying pulsed power from the power source 112, the light source lamp 111 is turned off only during the period from the time t1 to the time t2 in the field period T, and only during the period from the time t2 to the time t3. Lights up (see FIG. 2). When the lighting rate is 25% by supplying pulsed power from the power source 12, the light is turned off only during the period from time t1 to time t6 in the field period T, and is lit only during the period from time t6 to time t3 ( (See FIG. 2).

  That is, the light emission period of the light source lamp 111 is controlled by the pulse generation circuit 117 and the power source 112. Accordingly, the overall response of the image display light as the image display is, for example, when the lighting rate is 50%, the pulse-on waveform of the time from time t2 to time t3, and the pulse-on waveform of the time from time t4 to time t5 It becomes only. For this reason, the temporal spread of the display overall response is reduced, and the time frequency characteristic is improved to a flatter characteristic, so that the image quality deterioration at the time of moving image display is also improved.

  In this way, after the image signal for one frame to be displayed is written on the liquid crystal display panel and a predetermined time elapses, the backlight light source is turned on all over, thereby degrading image quality such as motion blur that occurs when displaying moving images. The improvement method is called a full flash type, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-201763, Japanese Patent Application Laid-Open No. 2002-55657, and the like in addition to the above Japanese Patent Application Laid-Open No. 9-325715.

  Further, for example, JP-A-11-202286, JP-A-2000-321551, and JP-A-2001-296838 disclose a plurality of divisions of the liquid crystal display panel with respect to the above-described full-flash type backlight lighting method. A so-called scanning-type backlight lighting method has been proposed in which the backlight light source is sequentially scanned and lit for each light-emitting divided region corresponding to the display region, thereby improving image quality degradation such as motion blur that occurs during video display. .

  A case in which the backlight is blinked at high speed sequentially so that the display state of the hold-type drive is close to the display of the impulse-type drive such as a CRT will be described with reference to FIGS. In FIG. 3, a plurality of (four in this case) direct fluorescent lamps (CCFT) 203 to 206 are arranged on the back surface of the liquid crystal display panel 202 in a direction parallel to the scanning lines, and are used as scanning signals of the liquid crystal display panel 202. The lamps 203 to 206 are sequentially lit up and down in synchronization. The lamps 203 to 206 correspond to display areas obtained by dividing the liquid crystal display panel 202 into four in the horizontal direction.

  FIG. 4 is a diagram showing the lighting timing of the lamp corresponding to FIG. In FIG. 4, the high state indicates the lighting state of the lamp. For example, a video signal is written at the timing of (1) in one frame period in the upper 1/4 divided display area in the liquid crystal display panel 202, and is delayed by the liquid crystal response period of (2) and (3). The fluorescent lamp 203 is turned on at the timing of (4). As described above, after the video signal is written, the operation of lighting only one lamp in each divided display area is sequentially repeated within one frame period.

  As a result, the display state of the liquid crystal hold type drive can be brought close to the display state of the CRT impulse type drive. Therefore, when the moving image is displayed, the video signal of the previous frame is not recognized, and the moving image due to the edge blur is generated. Deterioration of display quality can be prevented. As shown in FIG. 5, not only the same effect can be obtained by lighting two lamps at a time, but also the backlight lighting time can be extended, and the backlight brightness can be increased. Can be suppressed.

  Further, in this scanning type backlight lighting system, the light emitting area of the corresponding backlight light source is turned on at the timing when the liquid crystal optically responds sufficiently for each of the plurality of divided display areas of the liquid crystal display panel. It is possible to equalize the period from writing the image to the backlight light source regardless of the display screen position (up and down position), so the motion blur is sufficient regardless of the display screen position There is an advantage that can be improved.

  Further, in contrast to the backlight intermittent drive method described above, the backlight light source is not intermittently driven within one frame period, but the video signal and the black signal are repeatedly written into the liquid crystal display panel within one frame period. A so-called black writing type liquid crystal which realizes a pseudo impulse type display by shortening a light emission time (image display period) of a pixel from scanning a frame of a video signal to scanning a next frame. Display devices have been proposed.

As such a black writing type liquid crystal display device, for example, as shown in FIG. 6A, after sequentially writing one frame of input image data to the liquid crystal display panel, the entire screen is simultaneously displayed. By writing the black display data, the entire screen is displayed in black for a predetermined period, or as shown in FIG. 6B, the black display data is sequentially written for each scanning line, so that a part of the screen is predetermined. It is known that black display is performed for a period and the image display period within one frame period is shorter than that of the conventional hold type display (Japanese Patent Laid-Open Nos. 9-127717 and 11-109921).
JP-A-9-325715 JP 2001-201763 A JP 2002-55657 A JP-A-11-202286 JP 2000-321551 A JP 2001-296838 A Japanese Patent Laid-Open No. 9-127717 JP-A-11-109921

  In the conventional technology described above, in order to improve image quality degradation due to motion blur that occurs when displaying a moving image in a hold-type display device, the backlight intermittently occurs within one frame period (for example, 16.7 msec in the case of 60 Hz progressive scan). By driving or writing a black display signal to the liquid crystal display panel after the image display signal, the image display period is shortened, and the display state of the hold-type drive is approximated to the display of the impulse-type drive such as a CRT. Is.

  Here, in order to improve image quality degradation due to motion blur, it is desirable to reduce the impulse rate (the ratio of the image display period within one frame period). However, if the impulse rate is reduced, the following (1) to ( There is a possibility of inviting problems as shown in 3).

  (1) Depending on the image, the degree of motion blur (Motion Blur) varies. For example, in the case of CG (computer graphics), animation, game images, etc., as shown in FIG. Of these, only a discrete image (that is, a certain moment for each frame) is drawn, and motion blur that serves to interpolate an intermediate time between frames may not be added.

  When using motion blur that has been processed by image processing, the motion looks smooth, but when there is no motion blur, that is, a content image that is not originally smooth, displayed with a reduced impulse rate, the motion image However, the stroboscopic interference that appears to be flying apart is generated, leading to degradation of image quality.

  In addition, the image taken with a storage camera that is normally used as a television camera is an integral of the continuous time during which the shutter is open, so the amount of motion blur differs depending on the shutter speed. The accompanying indoor shot images (for example, relay of indoor programs such as news programs and swimming) have a high shutter speed (shutter opening time is short). Therefore, as shown in FIG. There is little motion blur added, and when an image with few such motion blurs is displayed with a small impulse rate, there is a high possibility that the above-mentioned stroboscopic interference will occur.

  On the other hand, images shot in the dark outdoors such as baseball or soccer night games may have a low shutter speed (long shutter opening time), so as shown in FIG. A lot of motion blur will be added, and even if images with a lot of motion blur are displayed with a small impulse rate, smooth motion can be expressed with motion blur. It is preferable that priority is given to the display of a moving image with no blurring and reduced motion blur.

  (2) The visual characteristics when viewing a movie are considered to be the non-linearity of visual response to eye movement, visual time integration effect, and light stimulus intensity. The characteristics of the follower movement (the movement in which the left and right eyes follow the moving body in the same way) are the most important characteristics for perception, depending on the moving speed of the moving image, etc. The above-described stroboscopic interference may occur.

  For example, in the case of an image in which the entire screen moves uniformly in the horizontal direction (pan movement) as in sports broadcasts such as soccer and volleyball, image quality deterioration due to motion blur is conspicuous, so by reducing the impulse rate as much as possible, Although it is preferable to realize a sharp moving image display by reducing motion blur, if the image is such that the background is moving with the person of interest fixed, if the impulse rate is reduced, the above-mentioned stroboscopic interference will occur. There is a high possibility of incurring image quality degradation.

  (3) Further, if the impulse rate is reduced, the motion blur disturbance of the moving image can be reduced. However, since the black display period (image non-display period) within one frame period increases, the white image is displayed particularly. Flicker is conspicuous in the portion, and this flicker causes image quality deterioration.

  As described above, depending on the type of image content, if the impulse rate is reduced, image quality interference such as stroboscopic and flickering may occur, resulting in image quality degradation, and overall improvement in image quality is realized. There was a problem that it was difficult to do.

  In addition, the optimal impulse rate varies depending on the image content and image content, and perception sensitivity (moving visual acuity) with respect to motion blur, stroboscopic and flicker is large due to individual differences between users. There is a problem that it is difficult to improve the overall image quality.

  The present invention has been made in view of the above problems, and by variably controlling the ratio of the image display period within one frame period in response to a user's selection instruction input regarding the impulse rate, motion blur and stroboscopic It is an object of the present invention to provide a liquid crystal display device capable of appropriately suppressing deterioration of image quality due to various factors such as flicker and realizing a comprehensive image quality improvement for a user.

A first invention of the present application is a liquid crystal display device in which a display period and a non-display period of an image signal to be displayed are provided in one frame period, and the ratio of the display period of the image signal in the one frame period is determined. Means for on-screen display of an impulse rate setting screen for setting;
And a means for variably controlling the ratio of the display period of the image signal within the one frame period based on selection instruction information of the impulse rate by the user.

  According to a second aspect of the present invention, the means for variably controlling the ratio of the display period of the image signal within the one frame period variably controls the lighting time of the backlight light source disposed on the back surface of the liquid crystal display panel. It is characterized by being.

  According to a third invention of the present application, a means for variably controlling the ratio of the display period of the image signal within the one frame period is provided between the backlight source disposed on the back surface of the liquid crystal display panel and the liquid crystal display panel. The light transmission period of the shutter means provided in is variably controlled.

  According to a fourth aspect of the present invention, the means for variably controlling the ratio of the display period of the image signal within the one frame period varies the period during which the voltage applied to the liquid crystal display panel is held based on the image signal. It is what controls.

  The fifth invention of the present application is characterized in that the gradation level of the input image signal is varied in accordance with the ratio of the display period of the image signal within the one frame period.

  The sixth invention of the present application is characterized in that a gradation voltage to be applied to the liquid crystal panel is varied corresponding to an input image signal in accordance with a ratio of the display period of the image signal within the one frame period. .

  Since the liquid crystal display device of the present invention has the above-described configuration, the ratio of the image display period in one frame period is variably controlled based on the selection instruction information of the impulse rate by the user, so that motion blur and strobe It is possible to appropriately suppress image quality deterioration due to various factors such as scoping and flicker, and to realize comprehensive image quality improvement for the user.

  Embodiments of the present invention will be described below.

  First, first to fourth embodiments, which are liquid crystal display devices that automatically switch the impulse rate according to the detection result of the content type to be displayed, will be described.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. Here, FIG. 8 is a functional block diagram showing a schematic configuration of the main part of the liquid crystal display device of the present embodiment, FIG. 9 is an explanatory diagram for explaining an example of the basic operation principle of the liquid crystal display device of the present embodiment, and FIG. These are explanatory drawings for explaining another example of the basic operation principle in the liquid crystal display device of the present embodiment.

  As shown in FIG. 8, the liquid crystal display device according to the present embodiment performs input multiplexing of images, audio data, and control data (content information, etc.) that have been compression-encoded using the MPEG (Moving Picture Expert Group) method or the like. Each data is separated from the data (transport stream), and output to each of the image decoding unit 2, the audio decoding unit (not shown), the control CPU 10, and the separated image data. And an image decoding unit 2 that performs MPEG decoding.

  In addition, a frame frequency conversion unit 3 that converts the frame frequency of the decoded input image signal to a high frequency, a gradation conversion unit 4 that converts the gradation level of the input image signal, and a liquid crystal display based on the input image signal An electrode driving unit 5 for driving data electrodes and scanning electrodes of the panel 6 and an active matrix liquid crystal display panel 6 are provided.

  Further, a direct type backlight light source 7 disposed on the back surface of the liquid crystal display panel 6 and a light source driving unit that intermittently drives the backlight light source 7 to be turned off / on within one vertical display period (one frame period). 8, a synchronization signal extraction unit 9 that extracts a synchronization signal from the input image signal decoded by the image decoding unit 2, and content information is acquired and analyzed from the control data separated by the demultiplexing unit 1, And a control CPU 10 that outputs a control signal for controlling the timing of turning on / off the backlight light source 7 to the light source drive unit 8 based on the vertical synchronization signal extracted by the synchronization signal extraction unit 7.

  Here, the content information included in the control data is program information included in digital broadcast data transmitted from a broadcasting station using CS (Communication Satellite), BS (Broadcasting Satellite), or the like. Content information read from a disc medium such as genre information or a DVD (Digital Versatile Disc) can be used. By analyzing these, the control CPU 10 detects and discriminates the content type of the image to be displayed. For example, the control CPU 10 refers to the ROM in which the impulse rate information for each image content type is stored in advance, thereby the backlight lighting period. A control signal for changing the (image display period) is generated.

  Here, the content type means a type of sports, drama, news, animation, game, or the like. Note that the control CPU 10 has shooting information in which shooting conditions such as shutter speed are described in addition to EPG (electronic program guide) information in which the program genre, category, and the like are described as the content information included in the broadcast data. If there is additional information such as motion blur, the content type of the image to be displayed can be detected based on the additional information. In addition to the content information included in the broadcast data described above, video source (video position) selection instruction information input by the user from a menu setting screen or the like, EPG (electronic program guide) acquired from an external medium (medium) It is also possible to determine the content type of the image to be displayed based on the information, shooting condition information added to the image data when the user shot and recorded (details will be described later).

  Further, the control CPU 10 controls the light source driving unit 8 so as to vary the light emission luminance of the backlight light source 7 with the variable control of the lighting period (image display period) of the backlight light source 7 or the input image signal. The gradation converting unit 4 is controlled so as to vary the gradation level. Here, even if the lighting period (lighting rate) of the backlight light source 7 is shortened, the light emission luminance (backlight luminance) of the backlight light source 7 is increased so that the relationship between the input image signal and the display luminance is constant. The tone conversion unit 4 converts the input image signal level.

  In addition, the gradation conversion unit 4 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the gradation conversion unit 4 converts the conversion table into the conversion table (LUT). The input image signal level (gradation level) is converted with reference. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  Further, if the impulse rate is decreased without changing the light emission luminance of the backlight light source 7, pixels with low luminance will be crushed, so the input image signal level (gradation level) is converted to increase the display luminance, If the contrast of dark gradation is increased or the impulse rate is increased, pixels with high brightness will be destroyed. Therefore, the display brightness is reduced by converting the input image signal level (gradation level). By increasing the contrast, it is also possible to realize a sharp image display.

  Further, the control CPU 10 controls the frame frequency conversion unit 3 so as to vary the frame frequency of the image signal supplied to the liquid crystal display panel 6 as necessary. The frame frequency conversion unit 3 includes, for example, a frame memory, stores an image of one frame of the input image signal in the frame memory, and then converts it to a predetermined frame frequency based on a control signal from the control CPU 10. By outputting the processed image signal, the time axis compression of the input image signal is performed.

  The backlight light source 7 may be a direct type or side illumination type LED light source, an EL light source, or the like in addition to the direct type fluorescent lamp. In particular, LEDs (light emitting diodes) have a response speed of several tens to several hundreds ns, and are more responsive than the ms order of fluorescent lamps. Is possible.

  The liquid crystal display device of the present embodiment prevents motion blur that occurs during moving image display by a full-flash type backlight lighting system. That is, after the entire scanning (image writing) of the display screen has been completed, the drive waveform is applied to the backlight light source 7 after being delayed by a predetermined time period, and the hatched portion in FIG. During the backlight lighting period indicated by, the backlight light source 7 is turned on all at once (flash emission) on the entire display screen.

  Here, the backlight lighting period indicated by the hatched portion in FIG. 9, that is, the image display period (impulse rate) within one frame period is varied based on the type of image content to be displayed. Comprehensive image quality improvement is realized by appropriately suppressing image quality degradation caused by factors such as scoping and flicker.

  For example, in FIGS. 9A to 9C, the frame frequency conversion unit 3 always converts the frame frequency (60 Hz) of the input image signal to four times 240 Hz, and variably controls the backlight lighting timing. The operation example in the case of switching the impulse rate to three stages of 30%, 40% and 50%, respectively, is shown.

  That is, if the input image content is taken in a dark field such as baseball or soccer night game (see FIG. 7C), it is likely that the input image content was shot at a low shutter speed. Even if the amount of motion blur is large and the impulse rate is small, there is little possibility of image quality interference such as stroboscopic and flicker.

  For this reason, as shown in FIG. 9A, a period sufficiently longer than a predetermined liquid crystal response period (here, a period of 45% of one frame period) after the completion of the image writing scan. Then, the backlight light source 7 is turned on, and the backlight lighting period (image display period) is held until the image writing scanning of the next frame is started. As a result, the impulse rate is set to 30%, the occurrence of motion blur is prevented and a sharp moving image display is realized, and the smooth motion of the moving image due to motion blur can be expressed.

  In addition, when the input image content is taken indoors with strong illumination such as a movie or a studio (for example, a news program, a relay of indoor competition such as swimming) (see FIG. 7B), Since there is a high possibility of shooting at a high shutter speed, if the amount of motion blur is small and the impulse rate is small, image quality interference such as stroboscopic and flicker may occur.

  For this reason, as shown in FIG. 9B, after the image writing scan is completed, a period longer than a predetermined liquid crystal response period (here, 35% of one frame period) is set. Thereafter, the backlight light source 7 is turned on to increase the backlight lighting period (image display period). As a result, it is possible to express the smooth motion of the moving object image by setting the impulse rate to 40% and preventing the occurrence of motion blur while suppressing the occurrence of image quality interference such as stroboscopic and flicker.

  Furthermore, if the input image content is a computer without motion blur such as CG (computer graphics), animation, or a game (see FIG. 7A), the impulse rate is reduced to reduce stroboscopic, flicker, etc. There is a high possibility of image quality interference.

  For this reason, as shown in FIG. 9C, immediately after the image writing scan is completed, it is delayed by a predetermined liquid crystal response period (here, a period of 25% of one frame period). The backlight light source 7 is turned on, and the backlight lighting period (image display period) is held until image writing scanning of the next frame starts. As a result, the impulse rate is set to 50%, the occurrence of motion blur is suppressed, and the occurrence of image quality interference such as stroboscopic and flicker is also prevented, thereby making it possible to express the smooth motion of the moving object image.

  As described above, depending on the image content to be displayed, the backlight lighting timing is delayed or the backlight extinguishing timing is advanced to change the backlight lighting period (image display period), thereby blurring motion. Image quality deterioration due to various factors such as stroboscopic and flicker can be appropriately suppressed, and overall image quality improvement can be realized.

  In the example shown in FIG. 9, the frame frequency of the display image signal is constant (240 Hz). For example, as shown in FIG. 10, the control CPU 10 controls the frame frequency converter 3 to control the display image signal. The impulse rate can be switched by changing the frame frequency and changing the backlight lighting period.

  For example, if the input image content is taken in a dark field such as baseball or soccer night game (see FIG. 7C), it is likely that the input image content was shot at a low shutter speed. Even if the amount of motion blur is large and the impulse rate is small, there is little possibility of image quality interference such as stroboscopic and flicker.

  For this reason, as shown in FIG. 10A, the frame frequency of the input image signal is converted to 240 Hz, which is four times, and the image writing scanning period is set to 25% of one frame period. After completion of the above, after a predetermined liquid crystal response period (here, a period of 25% of one frame period), the backlight light source 7 is turned on and image writing scanning of the next frame starts. Until this time, the backlight lighting period (image display period) is maintained. As a result, the impulse rate is 50%, it is possible to prevent the occurrence of motion blur and realize a sharp moving image display, and also to express the smooth movement of the moving object image by motion blur.

  In addition, when the input image content is taken indoors with strong illumination such as a movie or a studio (for example, a news program, a relay of indoor competition such as swimming) (see FIG. 7B), Since there is a high possibility of shooting at a high shutter speed, if the amount of motion blur is small and the impulse rate is small, image quality interference such as stroboscopic and flicker may occur.

  For this reason, as shown in FIG. 10B, by converting the frame frequency of the input image signal to 480 Hz, which is 8 times, the image writing scanning period is shortened to a period of 25% of one frame period. After completion of the writing scan, after a predetermined liquid crystal response period (here, a period of 25% of one frame period), the backlight light source 7 is turned on, and the backlight lighting period (image display) Period). As a result, the impulse rate is set to 62.5%, the occurrence of motion blur is suppressed, and the occurrence of image quality interference such as stroboscopic and flicker is also reduced, thereby making it possible to express the smooth motion of moving images. Become.

  Furthermore, if the input image content is a computer without motion blur such as CG (computer graphics), animation, or a game (see FIG. 7A), the impulse rate is reduced to reduce stroboscopic, flicker, etc. There is a high possibility of image quality interference.

  For this reason, as shown in FIG. 10 (c), the frame frequency conversion of the input image signal is not performed, and the backlight light source 3 is controlled to be always lit (continuously lit) ignoring the liquid crystal response period, By switching the impulse rate to 100% (complete hold-type display), it is possible to express the smooth motion of the moving image (if the motion image is blurred, image quality interference such as stroboscopic and flickering decreases) .

  As described above, by varying the backlight lighting period (image display period) within one frame period according to the image content to be displayed, image quality deterioration due to factors such as motion blur, stroboscopic, flicker, etc. Appropriate suppression is possible, and comprehensive image quality improvement can be realized. Further, in combination with the example shown in FIG. 9, it is possible to further improve the variable degree of freedom of the impulse rate according to the size and response characteristics of the liquid crystal display panel 6.

  In the above-described embodiment, the backlight lighting period, that is, the image display period (impulse rate) within one frame period, including the complete hold type display (impulse rate; 100%), is classified into the type of image content. However, the present invention is not limited to this, and it is needless to say that two or more predetermined impulse rates may be switched according to the type of image content. For example, an impulse type display and a hold type display (impulse type display off) may be configured to be switched alternatively.

  As content information, broadcast wave signals from broadcast stations and EPG (electronic program guide) information obtainable from external media (medium) are used, or additional information on motion blur related to input image content, shooting of shutter speed, etc. When the condition information can be acquired, it is possible to determine the type of image content to be displayed using this.

  In addition, in this type of image display device, the user inputs from the menu setting screen in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”. The video source (video position) can be selected and instructed. The type of image content to be displayed may be discriminated using the input video source selection instruction information by the user, and the impulse rate may be variably controlled. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this. As described above, the user instruction information regarding the video adjustment item may be used to determine the type of image content to be displayed, and the impulse rate may be variably controlled.

  As described above, the liquid crystal display device of the present embodiment uses a full-flash type backlight lighting method to approximate the display state of the impulse type drive, and the backlight lighting period, that is, according to the type of image content, that is, By appropriately switching the ratio (impulse rate) of the image display period within one frame period, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic, flicker, etc. Improvements can be realized.

  Further, the light emission luminance (backlight luminance) of the backlight light source 7 is varied according to the lighting period (impulse rate) of the backlight light source 7 within one frame period, and the gradation conversion unit 4 converts the level of the input image signal. Since the tone level is converted, the relationship between the input image signal and the display luminance can be kept constant regardless of the impulse rate.

  Note that, as in the above-described embodiment, the backlight light source 7 itself is not flash-lit (intermittently lit), but between the normal light (continuous lighting) backlight source and the liquid crystal display panel, one frame period The image display light may be modulated by providing shutter means such as an LCD for limiting the light transmission period (image display period).

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. 11 and FIG. 12, but the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. Here, FIG. 11 is an explanatory diagram for explaining an example of the basic operation principle in the liquid crystal display device of the present embodiment, and FIG. 12 is an illustration for explaining another example of the basic operation principle of the liquid crystal display device of the present embodiment. It is explanatory drawing.

  The liquid crystal display device of the present embodiment prevents motion blur that occurs during moving image display by a scanning backlight lighting system, but the basic functional block diagram is the first implementation described above with reference to FIG. It is the same as that of the form. The difference is that among backlight light sources 7 constituted by using a plurality of direct fluorescent lamps arranged in parallel with the scanning line, a plurality of direct or side illumination LED light sources, EL light sources, and the like. The predetermined number (number) is set as one light emitting area, and these are controlled to be sequentially scanned and lighted within one frame period. Based on the vertical / horizontal synchronization signal (scanning signal) extracted by the synchronization signal extraction unit 9 and the content information included in the control data separated by the demultiplexing unit 1, the control CPU 10 determines each light emitting region of the backlight light source. Controls the timing of sequential scan lighting.

  That is, in this embodiment, as shown in FIG. 11, after a scan (image writing) of a certain horizontal line group (display divided region) is completed, the horizontal line group is considered in consideration of the response delay of the liquid crystal. The light emitting area (a certain fluorescent lamp group or LED group) of the backlight source 3 corresponding to is turned on. This is repeated with the next region in the vertical direction. As a result, as indicated by the hatched portion in FIG. 11, the backlight lighting period can be sequentially shifted in units of light emitting regions with the passage of time corresponding to the writing scanning position of the image signal.

  Here, by varying the backlight lighting period of each light emitting region indicated by the hatched portion in FIG. 11, that is, the image display period (impulse rate) within one frame period, based on the type of image content to be displayed, Comprehensive image quality improvement is realized by appropriately suppressing image quality degradation caused by motion blur, stroboscopic, flicker, and other factors that occur according to image content.

  In the present embodiment, the control CPU 10 controls the light source driving unit 8 so as to vary the light emission luminance of the backlight light source 7 in accordance with the variable control of the lighting period (image display period) of the backlight light source 7. The gradation converter 4 is controlled so as to vary the gradation level of the input image signal. Here, even if the lighting period (lighting rate) of the backlight light source 7 is shortened, the light emission luminance (backlight luminance) of the backlight light source 7 is increased so that the relationship between the input image signal and the display luminance is constant. The tone conversion unit 4 converts the input image signal level.

  The gradation conversion unit 4 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the input image signal is referred to by referring to this conversion table. The level (gradation level) is converted. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  The control CPU 10 controls the frame frequency conversion unit 3 so as to vary the frame frequency of the image signal supplied to the liquid crystal display panel 6 as necessary. The frame frequency conversion unit 3 includes, for example, a frame memory, stores an image of one frame of the input image signal in the frame memory, and then converts it to a predetermined frame frequency based on a control signal from the control CPU 10. By outputting the processed image signal, the time axis compression of the input image signal is performed.

  For example, in FIGS. 11A to 11C, by changing the backlight lighting timing in each light emitting region of the backlight light source 7 without changing the frame frequency (60 Hz) of the input image signal, An operation example in the case where the image display period within one frame period is switched to three stages of 3/8 frame period, 1/2 frame period, and 5/8 frame period is shown.

  That is, if the input image content is taken in a dark field such as baseball or soccer night game (see FIG. 7C), it is likely that the input image content was shot at a low shutter speed. Even if the amount of motion blur is large and the impulse rate is small, there is little possibility of image quality interference such as stroboscopic and flicker.

  For this reason, as shown in FIG. 11A, a period sufficiently longer than a predetermined liquid crystal response period (here, a 1/2 frame period) after image writing scanning is completed in a certain horizontal line group. Then, the light emitting area of the backlight beam 7 corresponding to the horizontal line group is turned on, and the backlight lighting period (image display period) is held until the image writing scan of the next frame starts. As a result, the impulse rate is set to 37.5%, it is possible to prevent the occurrence of motion blur and realize a sharp moving image display, and to express the smooth motion of the moving object image by motion blur.

  In addition, when the input image content is taken indoors with strong illumination such as a movie or a studio (for example, a news program, a relay of indoor competition such as swimming) (see FIG. 7B), Since there is a high possibility of shooting at a high shutter speed, if the amount of motion blur is small and the impulse rate is small, image quality interference such as stroboscopic and flicker may occur.

  For this reason, as shown in FIG. 11B, a period longer than a predetermined liquid crystal response period (here, 3/8 frame period) after the completion of image writing scanning in a certain horizontal line group. Thereafter, the light emitting area of the backlight beam 7 corresponding to the horizontal line group is turned on to increase the backlight lighting period (image display period). As a result, it is possible to express the smooth motion of the moving object image by setting the impulse rate to 50% and preventing the occurrence of motion blur while suppressing the occurrence of image quality interference such as stroboscopic and flicker.

  Furthermore, if the input image content is a computer without motion blur such as CG (computer graphics), animation, or a game (see FIG. 7A), the impulse rate is reduced to reduce stroboscopic, flicker, etc. There is a high possibility of image quality interference.

  For this reason, as shown in FIG. 11C, after completion of the image writing scan in a certain horizontal line group, after a predetermined liquid crystal response period (here, 1/4 frame period) is delayed. The light emission area of the backlight light source 7 corresponding to the horizontal line group is immediately turned on, and the backlight lighting period (image display period) is held until the image writing scan of the next frame starts. As a result, the impulse rate can be set to 62.5%, and the occurrence of motion blur can be suppressed, and the occurrence of image quality interference such as stroboscopic and flicker can also be prevented, thereby expressing the smooth motion of the moving object image. Become.

  As described above, by varying the backlight lighting period (image display period) by delaying the backlight lighting timing in each light emitting area or by accelerating the backlight lighting timing according to the image content to be displayed. Therefore, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic, flicker, and the like, and overall image quality improvement can be realized.

  In the example shown in FIG. 11, the frame frequency of the display image signal is constant (60 Hz). For example, as shown in FIG. 12, the control CPU 10 controls the frame frequency conversion unit 3 to control the display image signal. The impulse rate can be switched by changing the frame frequency and changing the backlight lighting period.

  For example, if the input image content is taken in a dark field such as baseball or soccer night game (see FIG. 7C), it is likely that the input image content was shot at a low shutter speed. Even if the amount of motion blur is large and the impulse rate is small, there is little possibility of occurrence of interference such as stroboscopic and flicker.

  For this reason, as shown in FIG. 12A, the frame frequency conversion of the input image signal is not performed, and a predetermined liquid crystal response period (here, after the image writing scan is completed in a certain horizontal line group) , The light emission area of the backlight source 7 corresponding to the horizontal line group is turned on immediately, and the backlight lighting period (until the image writing scan of the next frame starts). Image display period). As a result, the impulse rate is set to 62.5%, it is possible to prevent the occurrence of motion blur and realize a sharp moving image display, and also to express the smooth motion of the moving object image due to motion blur.

  In addition, when the input image content is taken indoors with strong illumination such as a movie or a studio (for example, a news program, a relay of indoor competition such as swimming) (see FIG. 7B), Since there is a high possibility of shooting at a high shutter speed, if the amount of motion blur is small and the impulse rate is small, image quality interference such as stroboscopic and flicker may occur.

  For this reason, as shown in FIG. 12B, the frame frequency of the input image signal is converted to 240 Hz, which is four times, so that the image writing scanning period is shortened to a period of 1/4 of one frame. After the completion of the image writing scan in the line group, after delaying by a predetermined liquid crystal response period (here, 1/4 frame period), the backlight light source 7 corresponding to the horizontal line group is immediately The light emitting area is turned on to increase the backlight lighting period (image display period). As a result, the impulse rate is set to about 72%, the occurrence of motion blur is suppressed, and the occurrence of image quality interference such as stroboscopic and flicker is also reduced, so that the smooth motion of the moving object image can be expressed. .

  Furthermore, if the input image content is a computer without motion blur such as CG (computer graphics), animation, or a game (see FIG. 7A), the impulse rate is reduced to reduce stroboscopic, flicker, etc. There is a high possibility of image quality interference.

  For this reason, as shown in FIG. 12 (c), the frame frequency conversion of the input image signal is not performed, and the backlight light source 7 is controlled to be always lit (continuously lit) ignoring the liquid crystal response period, By switching the impulse rate to 100% (complete hold-type display), it is possible to express the smooth motion of the moving image (if the motion image is blurred, image quality interference such as stroboscopic and flickering decreases) .

  As described above, by varying the backlight lighting period (image display period) within one frame period according to the image content to be displayed, image quality deterioration due to factors such as motion blur, stroboscopic, flicker, etc. Appropriate suppression is possible, and comprehensive image quality improvement can be realized. Further, in combination with the example shown in FIG. 11, it is possible to further improve the variable degree of freedom of the impulse rate according to the size and response characteristics of the liquid crystal display panel 6.

  In the above-described embodiment, the backlight lighting period (image display period) within one frame period, that is, the impulse rate is set to the type of image content including the complete hold type display (impulse rate; 100%). However, the present invention is not limited to this, and it is needless to say that two or more predetermined impulse rates may be switched according to the type of image content. For example, an impulse type display and a hold type display (impulse type display off) may be configured to be switched alternatively.

  As content information, broadcast wave signals from broadcast stations and EPG (electronic program guide) information obtainable from external media (medium) are used, or additional information on motion blur related to input image content, shooting of shutter speed, etc. When the condition information can be acquired, it is possible to determine the type of image content to be displayed using this.

  In addition, in this type of image display device, the user inputs from the menu setting screen in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”. The video source (video position) can be selected and instructed. The type of image content to be displayed may be discriminated using the input video source selection instruction information by the user, and the impulse rate may be variably controlled. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this. As described above, the user instruction information regarding the video adjustment item may be used to determine the type of image content to be displayed, and the impulse rate may be variably controlled.

  In the above embodiment, the backlight light source 7 is divided into eight light emitting areas (horizontal line groups) and sequentially scanned. However, any number of the light emitting divided areas can be used as long as the number is two or more. It is obvious that each light emitting area is not limited to an area obtained by dividing the backlight light source 3 in the horizontal direction (direction parallel to the scanning line). Also in this respect, the setting of the light emission divided region can be made more flexible when the direct type planar LED is used as the backlight light source 7. Further, when an LED is used as the backlight light source 7, the backlight luminance can be controlled relatively easily by controlling the amount of drive current.

  As described above, in the liquid crystal display device of the present embodiment, the backlight lighting of each light emitting area is performed according to the type of image content in the case where the scanning backlight lighting method is used to approximate the display state of impulse driving. By appropriately switching the period, that is, the ratio (impulse rate) of the image display period within one frame period, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic and flicker. Image quality improvement can be realized.

  Further, the light emission luminance (backlight luminance) of the backlight light source 7 is varied according to the lighting period (impulse rate) of the backlight light source 7 within one frame period, and the gradation conversion unit 4 converts the level of the input image signal. Since the tone level is converted, the relationship between the input image signal and the display luminance can be kept constant regardless of the impulse rate.

  Note that, as in the above-described embodiment, the backlight light source 7 itself is not divided into a plurality of light emitting areas and sequentially lit up (intermittently lit). A shutter means such as an LCD for limiting the light transmission period (image display period) within one frame period for each divided display area may be provided between the display area and the image display light.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. 13 to 15. However, the same parts as those of the second embodiment are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 13 is a functional block diagram showing a schematic configuration of the main part of the liquid crystal display device of this embodiment, FIG. 14 is a timing chart for explaining the electrode driving operation in the liquid crystal display device of this embodiment, and FIG. It is explanatory drawing for demonstrating an example of the basic operation principle in the liquid crystal display device of embodiment.

  As shown in FIG. 14, in the liquid crystal display device of this embodiment, the backlight light source 7 is always in a lighting state (continuous lighting), and the writing display scan of the image display signal to the liquid crystal display panel 16 is continued within one frame period. The black writing type that performs writing scanning (reset scanning) of the black display signal prevents motion blur that occurs during moving image display. The control CPU 10 controls the electrode driving unit 5 based on the type of image content. The black display signal writing timing is controlled variably.

  That is, in the electrode driving unit 5, in addition to selecting each scanning line for image display, the scanning is performed again for black display, and an input image signal and a black display signal are supplied to the data line accordingly. Is performed in a cycle of one frame. Thus, a period (black display period) in which a black signal is displayed is generated between a certain frame image display and the next frame image display. Here, the writing timing (delay time) of the black display signal with respect to the writing timing of the image signal is varied according to the type of image content determined by the control CPU 10.

  Further, along with the variable control of the black display period, the control CPU 10 controls the light source driving unit 8 so as to vary the light emission luminance of the backlight light source 7 or the gradation so as to vary the gradation level of the input image signal. The converter 4 is controlled. Here, even when the image display period is shortened, the light emission luminance (backlight luminance) of the backlight light source 7 is increased and input by the gradation conversion unit 4 so that the relationship between the input image signal and the display luminance is constant. The image signal level is converted.

  In addition, the gradation conversion unit 4 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the input image signal is referred to by referring to this conversion table. The level (gradation level) is converted. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  FIG. 14 is a timing chart regarding the scanning lines (gate lines) of the liquid crystal display panel 6. The gate lines Y1 to Y480 are sequentially raised in order to write an image signal to the pixel cell via the signal line (data line) in one frame period with a slight shift in timing. One frame period is completed by starting all 480 gate lines and writing image signals to the pixel cells.

  At this time, the gate lines Y1 to Y480 are started again after a period determined based on the type of the image content from the start for writing the image signal, and each pixel cell is connected via the data line X. Supply a potential to display black. Thereby, each pixel cell is in a black display state. That is, each gate line Y goes high twice at different timings in one frame period. The pixel cell displays image data for a certain period by the first selection, and the pixel cell forcibly displays black by the second selection.

  For example, in FIGS. 15A to 15C, image display within one frame period can be performed by variably controlling the writing timing of the black display signal without changing the frame frequency (60 Hz) of the input image signal. An operation example in the case where the period is switched to three stages of a 1/4 frame period, a 1/2 frame period, and a 1 frame period is shown.

  That is, if the input image content is taken in a dark field such as baseball or soccer night game (see FIG. 7C), it is likely that the input image content was shot at a low shutter speed. Even if the amount of motion blur is large and the impulse rate is small, there is little possibility of image quality interference such as stroboscopic and flicker.

  For this reason, as shown in FIG. 15A, after the writing of the image display signal to a certain pixel is completed, the writing of the black display signal is started after a delay of ¼ frame period. The black display period (3/4 frame period) is held until image writing scanning of the frame starts. As a result, the impulse rate is set to 25%, it is possible to prevent the occurrence of motion blur and realize a sharp moving image display, and also to express the smooth motion of the moving object image by motion blur.

  In addition, when the input image content is taken indoors with strong illumination such as a movie or a studio (for example, a news program, a relay of indoor competition such as swimming) (see FIG. 7B), Since there is a high possibility of shooting at a high shutter speed, if the amount of motion blur is small and the impulse rate is small, image quality interference such as stroboscopic and flicker may occur.

  For this reason, as shown in FIG. 15B, after the writing of the image display signal to a certain pixel is completed, the writing of the black display signal is started after a delay of ½ frame period. The black display period (1/2 frame period) is held until image writing scanning of the frame starts. As a result, the image display period is increased, the impulse rate is set to 50%, the occurrence of motion blur is suppressed, and the occurrence of image quality interference such as stroboscopic and flicker is also reduced, so that the moving body image moves smoothly. It becomes possible to express.

  Furthermore, if the input image content is a computer without motion blur such as CG (computer graphics), animation, or a game (see FIG. 7A), the impulse rate is reduced to reduce stroboscopic, flicker, etc. There is a high possibility of image quality interference.

  For this reason, as shown in FIG. 15C, the impulse rate is set to 100 by controlling the black display signal to be eliminated without performing the black display signal writing scan (the image display period is maintained for one frame period). By switching to% (complete hold type display), it becomes possible to express the smooth motion of the moving object image (if the motion image is blurred, image quality interference such as stroboscopic and flicker decreases).

  As described above, by changing the black display signal supply period (image signal non-display period), that is, the image display period, according to the image content to be displayed, the image quality due to motion blur and stroboscopic factors. Deterioration can be appropriately suppressed, and overall image quality improvement can be realized.

  In the above-described embodiment, the image display period within one frame period, that is, the impulse rate, can be switched in three stages according to the type of image content, including a complete hold type display (impulse rate; 100%). However, the present invention is not limited to this, and it is needless to say that two or more predetermined impulse rates may be switched according to the type of image content. For example, an impulse type display and a hold type display (impulse type display off) may be configured to be switched alternatively.

  As content information, broadcast wave signals from broadcast stations and EPG (electronic program guide) information obtainable from external media (medium) are used, or additional information on motion blur related to input image content, shooting of shutter speed, etc. When the condition information can be acquired, it is possible to determine the type of image content to be displayed using this.

  In addition, in this type of image display device, the user inputs from the menu setting screen in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”. The video source (video position) can be selected and instructed. The type of image content to be displayed may be discriminated using the input video source selection instruction information by the user, and the impulse rate may be variably controlled. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this. As described above, the user instruction information regarding the video adjustment item may be used to determine the type of image content to be displayed, and the impulse rate may be variably controlled.

  In the present embodiment, the frame frequency of the input image signal (60 Hz) is supplied as it is to the liquid crystal display panel 16 without being converted, but it goes without saying that the frame frequency of the image signal may be varied. . In addition, by turning off the backlight light source 7 during the black display period, it is possible to shorten the backlight lighting period, thereby realizing a longer life and lower power consumption of the backlight light source 7. Here, when an LED is used as the backlight light source 7, it is possible to control the backlight luminance relatively easily by controlling the drive current amount.

  As described above, in the liquid crystal display device according to the present embodiment, an image display within one frame period is performed according to the type of image content, in the case where the black writing display method is used to approximate the display state of impulse driving. By appropriately switching the period ratio, that is, the impulse rate, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic, flicker, etc., and it is possible to realize comprehensive image quality improvement. .

  Further, the light emission luminance (backlight luminance) of the backlight light source 7 is varied according to the image display period (impulse rate) within one frame period, and the gradation level of the input image signal is converted by the gradation conversion unit 4. As a result, the relationship between the input image signal and the display luminance can be kept constant regardless of the impulse rate.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. 16 to 23. The same parts as those in the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 16 is a functional block diagram illustrating a schematic configuration of a main part of the liquid crystal display device of the present embodiment, FIG. 17 is a functional block diagram illustrating an electrode driving unit of the present embodiment, and FIG. 18 is a liquid crystal display device of the present embodiment. FIG. 19 is an explanatory diagram showing an example of the relationship of the transmittance to the applied voltage of the liquid crystal, and FIG. 20 is a response of the liquid crystal in the liquid crystal display device of the present embodiment. FIG. 21 is a block diagram showing a schematic configuration of a reference gradation voltage generating unit in the liquid crystal display device of the present embodiment. FIG. 22 is a schematic diagram of a main part of a signal line driving circuit in the liquid crystal display device of the present embodiment. FIG. 23 is a schematic explanatory diagram showing the gamma characteristics during hold-type display and impulse-type display in the liquid crystal display device of the present embodiment.

  In the present embodiment, basically, as in the third embodiment, the backlight light source 7 is always in a lighting state (continuous lighting), and scanning of image display signals to the liquid crystal display panel 6 is performed within one frame period. The black writing type that performs writing scanning (reset scanning) of the black display signal is to prevent motion blur that occurs during moving image display. The control CPU 10 controls the electrode driver based on the type of image content. The writing timing of the black display signal by 5a is variably controlled.

  In the third embodiment, when the impulse rate is changed by variable control of the black display period, in order to make the gamma characteristics substantially coincide with each other, a conversion table is prepared in advance, and the gradation conversion unit 4 converts the conversion table into the conversion table. Refer to and perform conversion processing. In contrast, in the present embodiment, as shown in FIG. 16, the gradation converting unit 4 is not provided, and instead of the gradation converting unit 4, the electrode driving unit 5 a corresponds to each impulse rate. The gradation voltage applied to the liquid crystal display panel 6 is varied so that the gamma characteristics are substantially matched.

  Further, along with the variable control of the black display period, the control CPU 10 controls the light source driving unit 8 so as to change the light emission luminance of the backlight light source 7 or changes the gradation voltage applied to the liquid crystal display panel 6. The electrode driving unit 5a is controlled. Here, even if the image display period is shortened, the light emission luminance (backlight luminance) of the backlight light source 7 is increased so that the relationship between the input image signal and the display luminance becomes constant, and the liquid crystal display is performed by the electrode driver 5a. The gradation voltage applied to the panel 6 is varied.

  Next, the configuration of the electrode driver 5a, the variable operation of the impulse rate by the black display signal, and the variable operation of the gradation voltage applied to the liquid crystal display panel 6 will be described in detail. As shown in FIG. 17, the electrode driver 5a has a reference gradation voltage data storage 31, a reference gradation voltage generator 32, a scanning line drive circuit 33, and a signal line drive circuit 34.

  When impulse-type display is performed, the scanning signal supplied from the scanning line driving circuit 33 to the scanning line (gate line Y) of the liquid crystal display panel 6 writes the gradation voltage corresponding to the image display signal to the pixel electrode. There are two scanning line selection periods within one frame period, an image display selection period and a black display selection period for writing a voltage corresponding to a black display signal to the pixel electrode. As a result, as shown in FIG. 14, each gate line Y goes high twice at different timings in one frame period. Further, the signal line driving circuit 34 alternately outputs a gradation voltage corresponding to the image display signal and a voltage corresponding to the black display signal to the liquid crystal display panel 6 from each signal line (data line X). Thus, the pixel cell displays an image display signal for a certain period by the first selection, and the pixel cell forcibly performs black display by the second selection.

  Here, the black display selection period is selected in accordance with the impulse rate, and black display is performed on scanning lines below or on a plurality of lines of the scanning line from which the image display selection period is selected. . A voltage corresponding to the black display signal is applied to the signal line in the black display selection period, and black display can be performed for each scanning line. The selection of the black display signal writing line and the image display signal writing line is realized by the control CPU 10 appropriately controlling the scanning line driving circuit 33. As a result, the image display signal writing line and the black display signal writing line are respectively scanned in a line-sequential manner with the upper and lower intervals maintained.

  The control CPU 10 also performs switching control between the image display signal and the black display signal of each frame. When attention is paid to one pixel column, an image display signal is displayed in an image display selection period for a certain line (row), a black display signal is displayed in a black display selection period for another line (row), and a liquid crystal display from the signal line driving circuit 34. Supplying to panel 6. As described above, by changing the ratio of the black display period in one frame period, it is possible to realize the impulse type display of each impulse rate.

  When hold-type display (impulse rate: 100%) is performed, the input image signal is supplied to the signal line drive circuit 34, and the scan line drive circuit 33 is controlled by the control CPU 10 so as to scan line-sequentially in one frame cycle. (The black display signal is not written). Thus, a normal hold type display with an impulse rate of 100% can be realized.

  Next, the gradation voltage changing operation applied to the liquid crystal display panel 6 will be described. The reference gradation voltage generator 32 supplies a reference gradation voltage to the signal line drive circuit 34 based on the reference gradation voltage data stored in the reference gradation voltage data storage 31. Here, as shown in FIG. 18, the reference gradation voltage data storage unit 31 corresponds to each impulse rate (in this case, impulse rate: 100% hold type display and impulse rate: 50% impulse type). Reference gradation voltage data (corresponding to the time of display) is stored in another area of the ROM, and these are selected and instructed by the control CPU 10 and output to the reference gradation voltage generator 32. The reference gradation voltage data stored in the reference gradation voltage data storage unit 31 is set as follows.

  First, the reference gradation voltage data corresponding to the hold type display (impulse rate: 100%) is based on the relationship between the applied voltage and the liquid crystal transmittance shown in FIG. The relationship of (liquid crystal transmittance) is set to be a relationship of gamma 2.2, for example. Here, for example, when the display signal level number, that is, the display data number is 256 gradations of 8 bits, the voltage data V0, V32, corresponding to 0, 32, 64, 96, 128, 160, 192, 224, and 255 gradations. .., V255 are set / stored, and for the gradations other than the stored reference gradation, the reference gradation voltage is linearly resistance-divided so that the entire floor is applied to the liquid crystal display panel 6. A regulated voltage is required.

  On the other hand, the reference gradation voltage data in the case of performing the impulse type display (impulse rate: 50%) is not immediately determined from the VT curve shown in FIG. 19, but at the time of the impulse type display shown in FIG. This is determined by obtaining the relationship between the integral value I of the luminance within one frame period and the voltage T applied to the liquid crystal in the time change of the display luminance (transmittance). The luminance integral value I varies depending on the response speed of the liquid crystal. Further, since the liquid crystal response speed varies depending on the display gradation, the relationship between the applied voltage and the liquid crystal transmittance (luminance) shown in FIG. That is, the desired gradation display cannot be performed with the gradation voltage when the hold-type display determined from the VT curve in FIG. 19 is performed.

  Therefore, when impulse-type display is performed, the relationship between the integral value I of luminance and the applied voltage is newly measured within one frame period, and reference gradation voltage data different from that in hold-type display is set. In setting the reference gradation voltage data, the relationship between the display gradation and the integral value I of the display luminance (liquid crystal transmittance) is set to be, for example, a relationship of gamma 2.2. Here, for example, when the display signal level number, that is, the display data number is 256 gradations of 8 bits, the voltage data V0, V32, corresponding to 0, 32, 64, 96, 128, 160, 192, 224, and 255 gradations. .., V255 are set / stored, and for the gradations other than the stored reference gradation, the reference gradation voltage is linearly resistance-divided so that the entire floor is applied to the liquid crystal display panel 6. A regulated voltage is required.

  As shown in FIG. 21, the reference gradation voltage generator 32 D / A converts the digital data V 0, V 32,..., V 255 acquired from the reference gradation voltage data storage 31 by the DA converter 51. Thereafter, the reference gradation voltages VA0, VA32,..., VA255 adjusted by appropriately amplifying by the amplifier unit 52 are supplied to the signal line driving circuit 34 including a source driver and the like. As shown in FIG. 22, the signal line drive circuit 34 has the input terminals of the reference gradation voltages VA0, VA32,..., VA255 joined by resistance division, and generates all gradation voltages corresponding to the image display signal. By doing so, an 8-bit image display signal can be displayed.

  Here, gradation voltages for nine reference gradations for every 32 gradations of 0, 32, 64, 96, 128, 160, 192, 224, and 255 are generated, and the gradation voltages other than this are divided by resistance. However, the present invention is not limited to this, and it is needless to say that the method may be applied to, for example, one that generates a gradation voltage with respect to a reference gradation for every 16 gradations.

  As described above, the reference gradation voltage data or the impulse type display (impulse rate; 50%) for the hold-type display (impulse rate; 100%) stored in the reference gradation voltage data storage unit 31 is used. Each of the reference gradation voltage data at the time of reading is read out to the reference gradation voltage generator 32 based on the control signal from the control CPU 10, and the input image signal is based on the reference gradation voltage data. The gradation voltage applied to the liquid crystal display panel 6 is determined corresponding to each gradation level.

  As a result, as shown in FIG. 23, regardless of whether hold-type display or impulse-type display is performed, the gamma characteristic caused by the difference in the response speed of the liquid crystal for each display gradation that occurs with black insertion. Therefore, it is possible to prevent an image quality deterioration caused by a change in gamma characteristics.

  In the liquid crystal display device of this embodiment, how to change the impulse rate based on the type of image content to be displayed is the same as that shown in the third embodiment. Description is omitted.

  As in the third embodiment, the gradation voltage is applied to the liquid crystal display panel 6 corresponding to the input image signal by changing the gradation level of the input image signal by providing a gradation conversion unit. In the case of such a configuration, the image data supplied to the control CPU 10 is substantially bit-compressed, and there is a possibility that the display capability is deteriorated by gradation conversion.

  On the other hand, by adjusting the reference gradation voltage itself supplied to the signal line driving circuit 34 as in the present embodiment, it is possible to suppress the change in gamma characteristic while maintaining the 8-bit display capability. For example, even when displaying a subtle gradation change such as gradation, high-quality display can be realized without displaying streak-like discontinuities.

  Note that, as in the fourth embodiment, a configuration in which the gradation voltage applied to the liquid crystal display panel corresponding to each gradation level of the input image signal is varied according to each impulse rate is the first to the first. Needless to say, the present invention may be applied to the third embodiment.

  Next, fifth to eighth embodiments which are liquid crystal display devices in which the user can arbitrarily change the impulse rate will be described.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described in detail with reference to FIGS. Here, FIG. 24 is a functional block diagram showing a schematic configuration of the main part of the liquid crystal display device of the present embodiment, and FIGS. 25 to 27 are explanatory diagrams and diagrams for explaining the basic operation principle of the liquid crystal display device of the present embodiment. 28 is an explanatory diagram showing an example of the impulse rate switching operation in the liquid crystal display device of the present embodiment, and FIG. 29 is an explanatory diagram showing an example of an impulse rate switching setting screen in the liquid crystal display device of the present embodiment.

  In this embodiment, as shown in FIG. 24, an active matrix type liquid crystal display panel 16 having a liquid crystal layer and electrodes for applying scanning signals and data signals to the liquid crystal layer, and an input image signal are used. An electrode driver 15 for driving the data electrodes and scanning electrodes of the liquid crystal display panel 16, a direct type backlight light source 17 disposed on the back surface of the liquid crystal display panel 16, and the backlight light source 17 in one vertical display. And a light source driving unit 18 that performs intermittent driving of turning off / on within a period (one frame period).

  Furthermore, a frame frequency conversion unit 13 that converts the frame frequency of the input image signal to a high frequency, a gradation conversion unit 14 that converts the gradation level of the input image signal, and a synchronization signal extraction that extracts a synchronization signal from the input image signal Unit 19, remote control light receiving unit 21 that receives an instruction signal input by a user using a remote controller (remote controller) (not shown), and an instruction signal received by remote control light receiving unit 21 is detected and analyzed, and synchronization signal extraction unit 19 And a control CPU 20 that outputs a control signal for controlling the timing of turning on / off the backlight light source 17 to the light source driving unit 18 based on the vertical synchronization signal extracted in step S2.

  Further, the control CPU 20 controls the light source driving unit 18 so as to change the light emission luminance of the backlight light source 17 in accordance with the variable control of the lighting period (image display period) of the backlight light source 17 or the input image signal. The gradation converting unit 14 is controlled so as to vary the gradation level. Here, even if the lighting period (lighting rate) of the backlight light source 17 is shortened, the light emission luminance (backlight luminance) of the backlight light source 17 is increased so that the relationship between the input image signal and the display luminance is constant. The tone conversion unit 14 converts the input image signal level.

  Further, the gradation conversion unit 14 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the gradation conversion unit 14 stores the conversion table. The input image signal level (gradation level) is converted with reference. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  Further, if the impulse rate is decreased without changing the light emission luminance of the backlight light source 7, pixels with low luminance will be crushed, so the input image signal level (gradation level) is converted to increase the display luminance, If the contrast of dark gradation is increased or the impulse rate is increased, pixels with high brightness will be destroyed. Therefore, the display brightness is reduced by converting the input image signal level (gradation level). By increasing the contrast, it is also possible to realize a sharp image display.

  Further, the control CPU 20 controls the frame frequency conversion unit 13 so as to vary the frame frequency of the image signal supplied to the liquid crystal display panel 16 as necessary. The frame frequency conversion unit 13 includes, for example, a frame memory, stores an image of one frame of the input image signal in the frame memory, and then converts the image to a predetermined frame frequency based on a control signal from the control CPU 20. By outputting the processed image signal, the time axis compression of the input image signal is performed.

  As the backlight light source 17, a direct type or side illumination type LED light source, EL light source, or the like can be used in addition to the direct type fluorescent lamp. In particular, LEDs (light emitting diodes) have a response speed of several tens to several hundreds ns, and are more responsive than the ms order of fluorescent lamps. Is possible.

  The liquid crystal display device of the present embodiment prevents motion blur that occurs during moving image display by a full-flash type backlight lighting system. That is, after the entire scanning of the display screen (writing of an image) is completed, the drive waveform is applied to the backlight light source 17 after being delayed by a predetermined time period, and thus, in FIGS. During the backlight lighting period indicated by the shaded area, the backlight light source 17 is turned on all at once (flash emission) on the entire display screen.

  Here, the backlight lighting period indicated by the shaded portion in FIGS. 25 to 27, that is, the image display period (impulse rate) within one frame period is based on an instruction input by the user using a remote controller (not shown). Therefore, the image quality degradation due to motion blur, stroboscopic, flicker, etc., which occurs according to the image content or image content, etc., is appropriately suppressed, realizing a comprehensive image quality improvement for the user. ing.

  For example, FIGS. 25A to 25C show operation examples when the impulse rate is variably controlled in three stages of 50%, 40%, and 30%, respectively. When it is desired to reduce the image quality disturbance due to the stroboscopic and flicker, as shown in FIG. 25A, after the image writing scan is completed, a predetermined response period of liquid crystal (in this case, 1/4) is used. After a delay of (frame period), the backlight light source 17 is turned on immediately, and the backlight lighting period (image display period) is held until image writing scanning of the next frame starts.

  Further, when there is no image quality interference due to stroboscopic or flicker, and it is desired to reduce the image quality interference due to motion blur, as shown in FIGS. 25B and 25C, the backlight lighting timing is delayed, The impulse rate is reduced by shortening the backlight turn-on timing or shortening the backlight turn-on period (image display period).

  Furthermore, in the example shown in FIG. 25, it is necessary to write and scan an image signal for one frame over the entire screen of the liquid crystal display panel 16 within a period excluding the liquid crystal response period and the backlight lighting period from one frame period. Therefore, the frame frequency conversion unit 13 converts the frame frequency (60 Hz) of the input image signal to four times 240 Hz. However, in order to ensure a sufficient backlight lighting period, the frame frequency conversion unit 13 is controlled by the control CPU 20. For example, as shown in FIG. 26, by converting the frame frequency of the input image signal to a higher frequency (480 Hz), the image writing scanning period is shortened and the impulse rate is increased to 62.5%. Can be made.

  Therefore, when image quality interference due to stroboscopic or flicker is conspicuous, a display image with a smooth movement can be obtained by increasing the backlight lighting period by variably controlling the frame frequency of the image signal based on a user instruction. (If the motion image is blurred, image quality interference such as stroboscopic and flickering is reduced). In this way, the degree of freedom in setting the backlight lighting period can be improved by converting the frame frequency of the input image signal to a high frequency as necessary.

  Further, when image quality interference due to stroboscopic and flicker is conspicuous, as shown in FIG. 27, the backlight source 17 is always turned on (continuously lit) ignoring the liquid crystal response period based on the user instruction. By controlling this, the impulse rate is switched to 100% (complete hold type display), and these image quality interferences can be completely prevented.

  As described above, in this embodiment, a complete hold type display (impulse rate; 100%) and an impulse type display (impulse rate; 62.5%, 50%, 40%, 30%) are designated by the user. It is possible to switch to 5 levels according to As shown in FIG. 28, this is configured such that each time a switch button provided on a remote control (not shown) is pressed, the screen is switched sequentially, or an impulse rate setting screen as shown in FIG. 29 is displayed. However, a desired impulse rate can be selected and switched by operating left and right keys provided on a remote controller (not shown). In the example shown in FIG. 29, the OSD is displayed on the screen to switch and guide “smooth movement” (hold type display) and “crisp movement” (impulse type display) in five stages.

  In the above-described embodiment, the backlight lighting period (image display period) within one frame period, that is, the impulse rate can be switched to five stages at 100% or less. However, the present invention is not limited to this. Needless to say, it may be possible to arbitrarily switch two or more predetermined impulse rates based on a user instruction. For example, the user may alternatively be able to switch between impulse-type display and hold-type display (impulse-type display off).

  Also, in this type of image display device, in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”, the user can input video from the menu setting screen. The source (video position) can be selected and instructed. The impulse rate may be variably controlled by using the input instruction information of the input video source by the user. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this.

  Furthermore, the impulse rate may be variably controlled using adjustment instruction information related to display brightness, contrast, and the like by the user. For example, in the video adjustment item on the menu setting screen, when an adjustment instruction is given to increase the contrast, the impulse rate can be increased in conjunction with this, and the switching control can be performed so as to improve the display luminance.

  As described above, the impulse rate is not limited to the user directly switching operation, and the impulse rate may be indirectly variably controlled in conjunction with a user instruction regarding various video adjustment items.

  As described above, the liquid crystal display device according to the present embodiment uses a full-flash type backlight lighting method to approximate an impulse-type display state, and in accordance with a user instruction, a backlight lighting period, that is, one frame. By appropriately switching the ratio of the image display period (impulse rate) within the period, it is possible to appropriately suppress image quality degradation due to various factors such as motion blur, stroboscopic, flicker, etc. Improvements can be realized.

  In addition, the light emission luminance (backlight luminance) of the backlight light source 17 is varied according to the lighting period (impulse rate) of the backlight light source 17 within one frame period, and the gradation conversion unit 14 converts the level of the input image signal. Since the tone level is converted, the relationship between the input image signal and the display luminance can be kept constant regardless of the impulse rate.

  Note that, as in the above-described embodiment, the backlight light source 17 itself is not flash-lit (intermittently lit), but between the normal light (continuous lighting) backlight light source and the liquid crystal display panel, one frame period. The image display light may be modulated by providing shutter means such as an LCD for limiting the light transmission period (image display period).

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described with reference to FIGS. 30 to 32. The same parts as those in the fifth embodiment are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 30 to FIG. 32 are explanatory views for explaining the basic operation principle in the liquid crystal display device of the present embodiment.

  The liquid crystal display device of the present embodiment prevents motion blur that occurs during moving image display by a scanning backlight lighting system. The basic functional block diagram of FIG. Is the same as The difference is that among backlight light sources 17 configured using a plurality of direct fluorescent lamps arranged in parallel with scanning lines, a plurality of direct or side illumination LED light sources, EL light sources, and the like. The predetermined number (number) is set as one light emitting area, and these are controlled so as to be sequentially scanned and lighted within one frame period. Based on the vertical / horizontal synchronization signal (scanning signal) extracted by the synchronization signal extraction unit 19 and the user instruction signal received by the remote control light receiving unit 21, the control CPU 20 sequentially scans and lights each light emitting area of the backlight light source. The timing is controlled.

  That is, in the present embodiment, as shown in FIG. 30, after the scanning (image writing) of a certain horizontal line group (display divided area) is completed, the horizontal line group is considered in consideration of the response delay of the liquid crystal. The light emitting area (a certain fluorescent lamp group or LED group) of the backlight source 17 corresponding to is turned on. This is repeated with the next region in the vertical direction. As a result, as indicated by the hatched portion in FIGS. 30 to 32, the backlight lighting period can be sequentially shifted in units of light emitting areas with the passage of time corresponding to the writing scanning position of the image signal. it can.

  Here, the user inputs the backlight lighting period of each light emitting area indicated by the hatched portion in FIGS. 30 to 32, that is, the image display period (impulse rate) within one frame period, using a remote controller (not shown). By changing according to the specified instruction, the image quality deterioration due to motion blur, stroboscopic, flicker, etc., which occurs according to the image content or image content, etc. is appropriately suppressed, and the overall image quality for the user Improvement has been realized.

  In the present embodiment, the control CPU 20 controls the light source driving unit 18 so as to vary the light emission luminance of the backlight light source 17 in accordance with the variable control of the lighting period (image display period) of the backlight light source 17. The gradation converter 14 is controlled so as to vary the gradation level of the input image signal. Here, even if the lighting period (lighting rate) of the backlight light source 17 is shortened, the light emission luminance (backlight luminance) of the backlight light source 17 is increased so that the relationship between the input image signal and the display luminance is constant. The tone conversion unit 14 converts the input image signal level.

  The gradation conversion unit 14 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the input image signal is referred to by referring to this conversion table. The level (gradation level) is converted. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  The control CPU 20 controls the frame frequency conversion unit 13 so as to vary the frame frequency of the image signal supplied to the liquid crystal display panel 16 as necessary. The frame frequency conversion unit 13 includes, for example, a frame memory, stores an image of one frame of the input image signal in the frame memory, and then converts the image to a predetermined frame frequency based on a control signal from the control CPU 20. By outputting the processed image signal, the time axis compression of the input image signal is performed.

  For example, in FIGS. 30A to 30C, the image display period in one frame period is variably controlled in three stages of 5/8 frame period, 1/2 frame period, and 3/8 frame period, respectively. An operation example is shown. When it is desired to reduce image quality interference due to stroboscopic and flicker, as shown in FIG. 30 (a), after the image writing scan is completed in a certain horizontal line group, a predetermined liquid crystal response period (here, After a delay of ¼ frame period), the light emitting area of the backlight beam 3 corresponding to the horizontal line group is immediately turned on, and the backlight lighting period is maintained until the image writing scan of the next frame starts. To do.

  When it is desired to reduce image quality disturbance due to motion blur, as shown in FIGS. 30B and 30C, the backlight lighting period is set by delaying the backlight lighting timing or by delaying the backlight lighting timing. By shortening, the impulse rate is reduced. Here, in order to prevent occurrence of luminance unevenness due to the screen position, the backlight lighting period of each light emitting region is determined for each frame and is not changed within one frame.

  In the example shown in FIG. 30, since the image signal for one frame is written and scanned over the entire screen of the liquid crystal display panel 16 within one frame period, the frame frequency (60 Hz) of the input image signal is changed. However, the control CPU 20 controls the frame frequency conversion unit 13 in order to ensure a sufficient backlight lighting period in each light emitting area. For example, as shown in FIG. 31, the frame frequency of the input image signal is set to a high frequency. By converting to (240 Hz), the image writing scanning period can be shortened and the impulse rate can be increased to about 72%.

  Therefore, when image quality interference due to stroboscopic or flicker is conspicuous, a display image with a smooth movement can be obtained by increasing the backlight lighting period by variably controlling the frame frequency of the image signal based on a user instruction. (If the motion image is blurred, image quality interference such as stroboscopic and flickering is reduced). As described above, the degree of freedom in setting the backlight lighting period can be improved by converting the frame frequency of the input image signal as necessary.

  Further, when image quality interference due to stroboscopic and flicker is conspicuous, as shown in FIG. 32, the backlight source 17 is always turned on (continuously lit) ignoring the liquid crystal response period based on a user instruction. By controlling the pulse rate to 100% and switching the impulse rate to 100% (complete hold type display), it is possible to completely prevent these image quality interferences.

  As described above, in this embodiment, a complete hold type display (impulse rate; 100%) and an impulse type display (impulse rate; about 72%, 62.5%, 50%, 37.5%) are provided. In accordance with a user instruction, it can be switched in five steps. As in the fifth embodiment, as shown in FIG. 28, this can be configured to sequentially switch each time a switch button provided on a remote controller (not shown) is pressed, or as shown in FIG. A desired impulse rate can be selected and switched by operating left and right keys provided on a remote controller (not shown) while displaying a screen for setting an appropriate impulse rate.

  In the above-described embodiment, the backlight lighting period (image display period) within one frame period, that is, the impulse rate can be switched to five stages at 100% or less. However, the present invention is not limited to this. Needless to say, it is only necessary to switch between two or more preset impulse rates based on a user instruction. For example, the user may alternatively be able to switch between impulse-type display and hold-type display (impulse-type display off).

  Also, in this type of image display device, in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”, the user can input video from the menu setting screen. The source (video position) can be selected and instructed. The impulse rate may be variably controlled by using the input instruction information of the input video source by the user. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this.

  Furthermore, the impulse rate may be variably controlled using adjustment instruction information related to display brightness, contrast, and the like by the user. For example, in the video adjustment item on the menu setting screen, when an adjustment instruction is given to increase the contrast, the impulse rate can be increased in conjunction with this, and the switching control can be performed so as to improve the display luminance.

  As described above, the impulse rate is not limited to the user directly switching operation, and the impulse rate may be indirectly variably controlled in conjunction with a user instruction regarding various video adjustment items.

  Further, in the above embodiment, the backlight source 17 is divided into eight light emitting areas (horizontal line groups) and sequentially scanned and lit. However, any number of light emitting divided areas may be used as long as the number is two or more. Further, it is obvious that each light emitting region is not limited to a region obtained by dividing the backlight light source 17 in the horizontal direction (direction parallel to the scanning line). Also in this respect, the setting of the light emission divided region can be made more flexible when the direct type planar LED is used as the backlight light source 17. In addition, when an LED is used as the backlight light source 17, it is possible to control the backlight luminance relatively easily by controlling the amount of drive current.

  As described above, in the liquid crystal display device according to the present embodiment, the backlight lighting period of each light emitting region according to a user instruction in the one that approaches the display state of the impulse type driving using the scanning backlight lighting method, In other words, by appropriately switching the ratio (impulse rate) of the image display period within one frame period, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic, flicker, etc. Image quality improvement can be realized.

  In addition, the light emission luminance (backlight luminance) of the backlight light source 17 is varied according to the lighting period (impulse rate) of the backlight light source 17 within one frame period, and the gradation conversion unit 14 converts the level of the input image signal. Since the tone level is converted, the relationship between the input image signal and the display luminance can be kept constant regardless of the impulse rate.

  Note that, as in the above-described embodiment, the backlight light source 17 itself is not divided into a plurality of light emitting areas and sequentially scanned (intermittently lit). A shutter means such as an LCD for limiting the light transmission period (image display period) within one frame period for each divided display area may be provided between the display area and the image display light.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described with reference to FIGS. 33 to 35. The same reference numerals are given to the same portions as those in the sixth embodiment, and the description thereof will be omitted. Here, FIG. 33 is a functional block diagram showing a schematic configuration of the main part of the liquid crystal display device of this embodiment, FIG. 34 is a timing chart for explaining the electrode driving operation in the liquid crystal display device of this embodiment, and FIG. It is explanatory drawing for demonstrating the basic principle of operation in the liquid crystal display device of embodiment.

  In the liquid crystal display device of the present embodiment, as shown in FIG. 33, the backlight light source 17 is always turned on (continuous lighting), and the writing display scan of the image display signal to the liquid crystal display panel 16 is continued within one frame period. The black writing type that performs writing scanning (reset scanning) of the black display signal prevents motion blur that occurs during moving image display. The control CPU 20 controls the electrode driving unit 15 based on a user instruction input. The black display signal writing timing is controlled variably.

  That is, the electrode driving unit 15 selects each scanning line again for black display in addition to selecting each scanning line, and supplies the input image signal and the black display signal to the data line accordingly. Is performed in a cycle of one frame. Thus, a period (black display period) in which a black signal is displayed is generated between a certain frame image display and the next frame image display. Here, the writing timing (delay time) of the black display signal with respect to the writing timing of the image signal is varied according to a user instruction.

  Further, along with the variable control of the black display period, the control CPU 20 controls the light source drive unit 18 so as to change the light emission luminance of the backlight light source 17 or changes the gradation level so as to change the gradation level of the input image signal. The converter 14 is controlled. Here, even if the image display period is shortened, the light emission luminance (backlight luminance) of the backlight light source 17 is increased and input by the gradation conversion unit 14 so that the relationship between the input image signal and the display luminance is constant. The image signal level is converted.

  Further, the gradation conversion unit 14 converts the input image signal level (gradation level) in order to display an image with matching gamma characteristics even when the impulse rate is changed. That is, for each impulse rate, a conversion table (LUT) for converting the input image signal level (gradation level) so as to match the gamma is stored in a ROM or the like, and the input image signal is referred to by referring to this conversion table. The level (gradation level) is converted. In this way, it is possible to suppress the occurrence of image quality degradation due to a change in gamma characteristics.

  FIG. 34 is a timing chart regarding the scanning lines (gate lines) of the liquid crystal display panel 16. The gate lines Y1 to Y480 are sequentially raised in order to write an image signal to the pixel cell via the signal line (data line) in one frame period with a slight shift in timing. One frame period is completed by starting all 480 gate lines and writing image signals to the pixel cells.

  At this time, the gate lines Y1 to Y480 are raised again after a period determined based on the user instruction from the rise for writing the image signal, and the black lines are supplied to the respective pixel cells via the data lines X. A potential for displaying is supplied. Thereby, each pixel cell is in a black display state. That is, each gate line Y goes high twice at different timings in one frame period. The pixel cell displays image data for a certain period by the first selection, and the pixel cell forcibly displays black by the second selection.

  For example, in FIGS. 35A to 35C, the image display period in one frame period is variably controlled in three stages of 3/4 frame period, 1/2 frame period, and 1/4 frame period, respectively. An operation example is shown. When it is desired to reduce image quality interference due to stroboscopic and flicker, as shown in FIG. 35 (a), after the writing of the image display signal to a certain pixel is completed, after a delay of 3/4 frame period, Writing of the black display signal is started, and the black display period (1/4 frame period) is held until the image writing scan of the next frame starts.

  Further, when it is desired to reduce image quality interference due to motion blur, as shown in FIGS. 35B and 35C, the black display signal supply period (image signal state) can be improved by advancing the black display signal writing start timing. The impulse rate is reduced by increasing the non-display period and shortening the image display period. Here, in order to prevent occurrence of luminance unevenness due to the screen position, the black writing timing (delay time) with respect to the image writing timing of each horizontal line is determined for each frame and is not changed within one frame.

  Further, when image quality interference due to stroboscopic and flicker is conspicuous, as shown in FIG. 32, control is performed so as to eliminate the black display period without performing the black display signal writing scan based on the user instruction. By switching the rate to 100% (complete hold type display), it is possible to completely prevent these image quality interferences.

  As described above, in this embodiment, a complete hold type display (impulse rate; 100%) and an impulse type display (impulse rate; approximately 75%, 50%, 25%) are displayed in response to a user instruction. It is possible to switch to the stage. As in the fifth embodiment, as shown in FIG. 28, this can be configured to sequentially switch each time a switch button provided on a remote controller (not shown) is pressed, or as shown in FIG. A desired impulse rate can be selected and switched by operating left and right keys provided on a remote controller (not shown) while displaying a screen for setting an appropriate impulse rate.

  In the above-described embodiment, the image display period (impulse rate) within one frame period can be switched to four stages at 100% or less. However, the present invention is not limited to this, and two or more preset values are set. Needless to say, the impulse rate may be arbitrarily switched based on a user instruction. For example, the user may alternatively be able to switch between impulse-type display and hold-type display (impulse-type display off).

  Also, in this type of image display device, in order to perform optimum image quality (video output characteristics) adjustment for each input video source such as “standard”, “movie”, and “game”, the user can input video from the menu setting screen. The source (video position) can be selected and instructed. The impulse rate may be variably controlled by using the input instruction information of the input video source by the user. For example, when “game” is selected in the selection item of the video source (video position) on the menu setting screen, switching control can be performed so as to increase the impulse rate in conjunction with this.

  Furthermore, the impulse rate may be variably controlled using adjustment instruction information related to display brightness, contrast, and the like by the user. For example, in the video adjustment item on the menu setting screen, when an adjustment instruction is given to increase the contrast, the impulse rate can be increased in conjunction with this, and the switching control can be performed so as to improve the display luminance.

  As described above, the impulse rate is not limited to the user directly switching operation, and the impulse rate may be indirectly variably controlled in conjunction with a user instruction regarding various video adjustment items.

  Furthermore, in this embodiment, the frame frequency of the input image signal (60 Hz) is supplied as it is to the liquid crystal display panel 16 without being converted, but it goes without saying that the frame frequency of the image signal may be varied. In addition, by turning off the backlight light source 17 during the black display period, it is possible to shorten the backlight lighting period, thereby realizing a longer lifetime and lower power consumption of the backlight light source 17. Here, when an LED is used as the backlight light source 17, the backlight luminance can be controlled relatively easily by controlling the drive current amount.

  As described above, in the liquid crystal display device according to the present embodiment, a black display period (image non-display period) is obtained in accordance with a user instruction in the case where the black writing type display method is used to approximate the impulse-type display state. In other words, by appropriately switching the ratio (impulse rate) of the image display period within one frame period, it is possible to appropriately suppress image quality degradation due to various factors such as motion blur, stroboscopic, flicker, etc. Comprehensive image quality improvement can be realized.

  Further, the light emission luminance (backlight luminance) of the backlight light source 17 is varied according to the ratio (impulse rate) of the image display period within one frame period, and the gradation level of the input image signal is converted by the gradation conversion unit 14. Therefore, regardless of the impulse rate, the relationship between the input image signal and the display luminance can always be constant.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described with reference to FIGS. 36, 37, and 18 to 23 used in the fourth embodiment. The same parts as those in the seventh embodiment have the same reference numerals. The description is omitted. Here, FIG. 36 is a functional block diagram showing a schematic configuration of a main part in the liquid crystal display device of the present embodiment, and FIG. 37 is a functional block diagram showing an electrode driving unit of the present embodiment.

  In the present embodiment, basically, as in the seventh embodiment, the backlight light source 17 is always in a lighting state (continuous lighting), and the image display signal is written and scanned to the liquid crystal display panel 16 within one frame period. The black writing type that performs writing scanning (reset scanning) of the black display signal is to prevent motion blur that occurs during moving image display. The control CPU 20 controls the electrode driving unit based on a user instruction input. The black display signal writing timing by 15a is variably controlled.

  In the seventh embodiment, when the impulse rate is changed by the black display period variable control, in order to make the gamma characteristics substantially coincide with each other, a conversion table is prepared in advance, and the gradation conversion unit 14 converts the conversion table into the conversion table. Refer to and perform conversion processing. In contrast, in the present embodiment, as shown in FIG. 36, the present embodiment does not include the gradation conversion unit 14, and instead of the gradation conversion unit 14, the electrode drive unit 15 a includes each impulse. The gradation voltage applied to the liquid crystal display panel 16 is varied in accordance with the rate, so that the gamma characteristics are substantially matched.

  Further, along with the variable control of the black display period, the control CPU 20 controls the light source driving unit 18 so as to change the light emission luminance of the backlight light source 17 or changes the gradation voltage applied to the liquid crystal display panel 16. The electrode driver 15a is controlled. Here, even if the image display period is shortened, the light emission luminance (backlight luminance) of the backlight light source 17 is increased so that the relationship between the input image signal and the display luminance becomes constant, and the liquid crystal display is performed by the electrode driver 15a. The gradation voltage applied to the panel 16 is varied.

Next, the configuration of the electrode driver 15a, the variable operation of the impulse rate by the black display signal, and the variable operation of the gradation voltage applied to the liquid crystal display panel 16 will be described in detail.
As shown in FIG. 37, the electrode driver 15a has a reference gradation voltage data storage part 131, a reference gradation voltage generator 132, a scanning line drive circuit 133, and a signal line drive circuit 134.

  When impulse-type display is performed, the scanning signal supplied from the scanning line driving circuit 133 to the scanning line (gate line Y) of the liquid crystal display panel 16 is an image for writing the gradation voltage corresponding to the image data to the pixel electrode. There are two scanning line selection periods in one frame period, a display selection period and a black display selection period for writing a voltage for black display to the pixel electrode. As a result, as shown in FIG. 34, each gate line Y goes high twice at different timings in one frame period. Further, the signal line driving circuit 134 alternately outputs a gradation voltage corresponding to the image display signal and a voltage corresponding to the black display signal from each signal line (data line X) to the liquid crystal display panel 16. Thus, the pixel cell displays an image display signal for a certain period by the first selection, and the pixel cell forcibly performs black display by the second selection.

  Here, the black display selection period is selected in accordance with the impulse rate, and black display is performed on scanning lines below or on a plurality of lines of the scanning line from which the image display selection period is selected. . A voltage corresponding to the black display signal is applied to the signal line in the black display selection period, and black display can be performed for each scanning line. The selection of the black display signal writing line and the image display signal writing line is realized by the control CPU 20 appropriately controlling the scanning line driving circuit 133. As a result, the image display signal writing line and the black display signal writing line are respectively scanned in a line-sequential manner with the upper and lower intervals maintained.

  The control CPU 20 also performs switching control between the image display signal and the black display signal of each frame. When attention is paid to one pixel column, an image display signal is output from the signal line driving circuit 134 to the image display signal in an image display selection period for a certain line (row), a black display signal is selected in the selection period for black display to another line (row) This is supplied to the display panel 16. As described above, by changing the ratio of the black display period in one frame period, it is possible to realize the impulse type display of each impulse rate.

  When hold-type display (impulse rate: 100%) is performed, the input image signal is supplied to the signal line driving circuit 134 and the scanning line driving circuit 133 is controlled by the control CPU 20 so as to perform line sequential scanning in one frame cycle. (The black display signal is not written). Thus, a normal hold type display with an impulse rate of 100% can be realized.

  Next, the gradation voltage changing operation applied to the liquid crystal display panel 6 will be described. The reference gradation voltage generator 132 supplies a reference gradation voltage to the signal line driving circuit 134 based on the reference gradation voltage data stored in the reference gradation voltage data storage 131. Here, as shown in FIG. 18, the reference gradation voltage data storage unit 131 corresponds to each impulse rate (in this case, impulse rate: 100% hold type display and impulse rate: 50% impulse type). Reference gradation voltage data (corresponding to the time of display) is stored in another area of the ROM, and these are selected and instructed by the control CPU 20 and output to the reference gradation voltage generator 132. The reference gradation voltage data stored in the reference gradation voltage data storage unit 131 is set as follows.

  First, the reference gradation voltage data corresponding to the hold type display (impulse rate: 100%) is based on the relationship between the applied voltage and the liquid crystal transmittance shown in FIG. The relationship of (liquid crystal transmittance) is set to be a relationship of gamma 2.2, for example. Here, for example, when the display signal level number, that is, the display data number is 256 gradations of 8 bits, the voltage data V0, V32, corresponding to 0, 32, 64, 96, 128, 160, 192, 224, and 255 gradations. .., V255 are set / stored, and for the gradations other than the stored reference gradation, the reference gradation voltage is linearly resistance-divided to linearly divide the entire gradation applied to the liquid crystal display panel 16. A regulated voltage is required.

  On the other hand, the reference gradation voltage data in the case of performing the impulse type display (impulse rate: 50%) is not immediately determined from the VT curve shown in FIG. 19, but at the time of the impulse type display shown in FIG. This is determined by obtaining the relationship between the integral value I of the luminance within one frame period and the voltage T applied to the liquid crystal in the time change of the display luminance (transmittance). The luminance integral value I varies depending on the response speed of the liquid crystal. Further, since the liquid crystal response speed varies depending on the display gradation, the relationship between the applied voltage and the liquid crystal transmittance (luminance) shown in FIG. That is, the desired gradation display cannot be performed with the gradation voltage when the hold-type display determined from the VT curve in FIG. 19 is performed.

  Therefore, when impulse-type display is performed, the relationship between the integral value I of luminance and the applied voltage is newly measured within one frame period, and reference gradation voltage data different from that in hold-type display is set. In setting the reference gradation voltage data, the relationship between the display gradation and the integral value I of the display luminance (liquid crystal transmittance) is set to be, for example, a relationship of gamma 2.2. Here, for example, when the display signal level number, that is, the display data number is 256 gradations of 8 bits, the voltage data V0, V32, corresponding to 0, 32, 64, 96, 128, 160, 192, 224, and 255 gradations. .., V255 are set / stored, and for the gradations other than the stored reference gradation, the reference gradation voltage is linearly resistance-divided to linearly divide the entire floor to be applied to the liquid crystal display panel 16. A regulated voltage is required.

  As shown in FIG. 21, the reference gradation voltage generation unit 132 D / A converts the digital data of V0, V32,..., V255 acquired from the reference gradation voltage data storage unit 131 by the DA converter 51. Thereafter, the reference gradation voltages VA0, VA32,..., VA255 adjusted by appropriately amplifying by the amplifier unit 52 are supplied to the signal line driving circuit 134 including a source driver and the like. As shown in FIG. 22, the signal line driving circuit 134 has the input terminals of the reference gradation voltages VA0, VA32,..., VA255 joined by resistance division, and generates all gradation voltages corresponding to the image display signal. By doing so, an 8-bit image display signal can be displayed.

  Here, gradation voltages for nine reference gradations for every 32 gradations of 0, 32, 64, 96, 128, 160, 192, 224, and 255 are generated, and the gradation voltages other than this are divided by resistance. However, the present invention is not limited to this, and it is needless to say that the method may be applied to, for example, one that generates a gradation voltage with respect to a reference gradation for every 16 gradations.

  As described above, the reference grayscale voltage data or the impulse type display (impulse rate; 50%) for the hold type display (impulse rate; 100%) stored in the reference grayscale voltage data storage unit 131 is used. Each of the reference gradation voltage data at the time of reading is read out to the reference gradation voltage generator 132 based on a control signal from the control CPU 20, and the input image signal is based on the reference gradation voltage data. The gradation voltage applied to the liquid crystal display panel 16 is determined corresponding to each gradation level.

  As a result, as shown in FIG. 23, regardless of whether hold-type display or impulse-type display is performed, the gamma characteristic caused by the difference in the response speed of the liquid crystal for each display gradation that occurs with black insertion. Therefore, it is possible to prevent an image quality deterioration caused by a change in gamma characteristics.

  In the liquid crystal display device of the present embodiment, how to change the impulse rate based on a user instruction is the same as that shown in the seventh embodiment, and thus detailed description thereof is omitted.

  As in the seventh embodiment, the gradation voltage is applied to the liquid crystal display panel 16 corresponding to the input image data by changing the gradation level of the image data by providing a gradation conversion unit. In the case of the configuration, the image data supplied to the control CPU 20 is substantially bit-compressed, and there is a possibility that the display capability is deteriorated by gradation conversion.

  On the other hand, by adjusting the reference gradation voltage itself supplied to the signal line driving circuit 134 as in the present embodiment, it is possible to suppress a change in gamma characteristic while maintaining the 8-bit display capability. For example, even when displaying a subtle gradation change such as gradation, high-quality display can be realized without displaying streak-like discontinuities.

  Note that, as in the eighth embodiment, a configuration in which the gradation voltage applied to the liquid crystal display panel corresponding to each gradation level of the input image signal is varied according to each impulse rate is described in the fifth to fifth embodiments. Needless to say, the present invention may be applied to the seventh embodiment.

  In the fifth to eighth embodiments of the present invention described above, the user instruction input related to the variable setting of the impulse rate is performed using a remote controller (not shown). However, the operation unit provided on the apparatus main body is used. Needless to say, the user instruction may be input.

  In the case of automatically switching the impulse rate according to the detection result of the image content type to be displayed (first to fourth embodiments), for example, no motion blur is added to the game (CG animation) image. The impulse rate is increased on the premise of this, but for game (CG animation) images with motion blur added by advanced image processing, the impulse rate is reduced to prevent motion blur interference. It is desirable to do. However, even in such a case, as in the fifth to eighth embodiments described above, the optimum impulse according to the image to be displayed can be configured by allowing the user to select an arbitrary impulse rate. It is possible to set the rate.

  Further, in this type of display device, as shown in FIG. 38, the display brightness is variably controlled according to the ambient light illuminance (brightness) in the usage environment of the device, for example, when the display surface is exposed to direct sunlight. Even if the user is viewing or viewing in a dark room, a screen display that is always easy for the user to see is realized. Therefore, it is desirable to increase the impulse rate when the ambient light illuminance is high in the usage environment of the apparatus, and to decrease the impulse rate when the ambient light illuminance is dark. ), The user can set an optimal impulse rate, and in addition to improving the image quality by preventing motion blur, it is possible to easily realize an image display that is easy for the user to see by display luminance modulation.

  In particular, when the impulse rate is automatically switched according to the ambient light illuminance level (ambient brightness) detected by the illuminance sensor, for example, in a place where direct sunlight on a part of the display screen is exposed to sunlight. When installed, the error of the detected illuminance by the illuminance sensor increases, and there is a possibility that the optimum display luminance cannot be obtained. However, as in the fifth to eighth embodiments described above, the user can set an arbitrary impulse rate. Can be selected, it is possible to set an optimal impulse rate according to the illuminance of outside light in the usage environment of the apparatus, and it is possible to realize an image display that is always easy for the user to see.

  Further, as shown in FIG. 39, it is known that the response speed of the liquid crystal has a very large temperature dependency, particularly the followability to an input signal at a low temperature is extremely deteriorated, and the response time is increased. In other words, when the temperature inside the device is low, a longer liquid crystal response period is ensured, and after the liquid crystal has fully responded to reach the target brightness, the backlight light source is turned on or a black display signal (image display) It is desirable to start writing the signal). Therefore, by setting an optimal impulse rate according to the temperature in the apparatus, the user can improve the image quality by preventing motion blur, as well as afterimage such as tailing. It is possible to suppress the occurrence and improve the display quality of the moving image.

  In particular, when the impulse rate is automatically switched in accordance with the temperature inside the apparatus (panel temperature) detected by the temperature sensor, for example, a place where a blower of an air conditioner hits a partial area of the display screen, or a date When installed in a place exposed to direct sunlight, the temperature error detected by the temperature sensor increases, and the optimal liquid crystal response period cannot be secured, leading to the occurrence of afterimages such as tailing. However, as in the fifth to eighth embodiments described above, an optimum impulse rate corresponding to the temperature in the device (panel temperature) is set by configuring the user to select an arbitrary impulse rate. It is possible to display a moving image that is always good for the user.

  In addition, by configuring the user to select an arbitrary impulse rate, special user-specific features such as intentionally displaying awkward movements (stroboscopic) and blurry movements (motion blur) are provided. It is also possible to perform simple video expression.

  As described above, the present invention is a liquid crystal display device that writes an image signal to be displayed on a liquid crystal display panel and intermittently lights a backlight light source within one frame period, and detects the type of image content to be displayed. And means for variably controlling the lighting time of the backlight light source based on the type of the detected image content.

  Further, the backlight light source emits flash over the entire frame every frame period in synchronization with a vertical synchronizing signal supplied to the liquid crystal display panel.

  Further, the backlight light source sequentially scans and lights a plurality of light emitting areas in synchronization with a vertical synchronizing signal and a horizontal synchronizing signal supplied to the liquid crystal display panel.

  In addition, the emission intensity of the backlight light source is varied according to the lighting period of the backlight light source.

  Further, the gradation level of the input image signal is varied according to the lighting period of the backlight light source.

  Further, according to the lighting period of the backlight light source, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal.

  Further, the frame frequency of the input image signal is varied based on the type of the image content.

  In addition, the type of image content to be displayed is detected based on content information included in broadcast data.

  Furthermore, the type of image content to be displayed is detected based on content information obtained from an external medium.

  Further, the type of the image content to be displayed is detected based on the video source selection instruction information input by the user.

  Furthermore, the present invention is a liquid crystal display device for writing an image signal to be displayed and a black display signal to a liquid crystal display panel within one frame period, the means for detecting the type of image content to be displayed, and the detection And a means for variably controlling a period during which the black display signal is supplied to the liquid crystal display panel based on the type of the image content.

  The light emission intensity of the backlight light source that irradiates the liquid crystal display panel may be varied according to the supply period of the black display signal.

  Furthermore, the gradation level of the input image signal is varied according to the supply period of the black display signal.

  Further, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal in accordance with the supply period of the black display signal.

  Further, the type of image content to be displayed is detected based on content information included in the broadcast data.

  Further, the type of image content to be displayed is detected based on content information obtained from an external medium.

  Furthermore, the type of image content to be displayed is detected based on video source selection instruction information input by the user.

  Further, the present invention is a liquid crystal display device in which a display period and a non-display period of an image signal to be displayed on a liquid crystal panel are provided within one frame period, and means for detecting the type of image content to be displayed; Means for variably controlling the ratio of the display period of the image signal within the one frame period based on the type of the detected image content.

  Furthermore, the gradation level of the input image signal is varied in accordance with the ratio of the display period of the image signal within the one frame period.

  Further, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal in accordance with the ratio of the display period of the image signal within the one frame period.

  Further, the type of image content to be displayed is detected based on content information included in the broadcast data.

  In addition, the type of image content to be displayed is detected based on content information obtained from an external medium.

  Furthermore, the type of image content to be displayed is detected based on video source selection instruction information input by the user.

  According to another aspect of the present invention, there is provided a liquid crystal display device for writing an image signal to be displayed on a liquid crystal display panel and lighting a backlight light source intermittently within one frame period. And a means for variably controlling the lighting time of the backlight light source based on a user instruction.

  Further, the backlight light source emits flash over the entire frame every frame period in synchronization with a vertical synchronizing signal supplied to the liquid crystal display panel.

  Further, the backlight light source sequentially scans and lights a plurality of light emitting areas in synchronization with a vertical synchronizing signal and a horizontal synchronizing signal supplied to the liquid crystal display panel.

  Furthermore, the emission intensity of the backlight light source is varied according to the lighting period of the backlight light source.

  Further, the gradation level of the input image signal is varied according to the lighting period of the backlight light source.

  Further, according to the lighting period of the backlight light source, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal.

  Further, the frame frequency of the input image signal is varied based on the user instruction.

  Further, the lighting time of the backlight light source is varied based on video source selection instruction information input by the user.

  In addition, the lighting time of the backlight light source is varied based on video adjustment instruction information input by the user.

  Furthermore, the present invention is a liquid crystal display device for writing an image signal to be displayed and a black display signal on a liquid crystal display panel within one frame period, the means for detecting user instruction input, and the detected user instruction. And a means for variably controlling a period during which the black display signal is supplied to the liquid crystal display panel.

  The light emission intensity of the backlight light source that irradiates the liquid crystal display panel may be varied according to the supply period of the black display signal.

  Furthermore, the gradation level of the input image signal is varied according to the supply period of the black display signal.

  Further, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal in accordance with the supply period of the black display signal.

  Furthermore, the supply period of the black display signal is varied based on video source selection instruction information input by the user.

  The black display signal supply period may be varied based on video adjustment instruction information input by a user.

  Furthermore, the present invention provides a liquid crystal display device in which a display period and a non-display period of an image signal to be displayed on a liquid crystal panel are provided within one frame period, the means for detecting a user instruction input, and the detected user And a means for variably controlling the ratio of the display period of the image signal within the one frame period based on the instruction.

  Further, the gradation level of the input image signal is varied in accordance with the ratio of the display period of the image signal within the one frame period.

  Further, the gradation voltage applied to the liquid crystal panel is varied corresponding to the input image signal in accordance with the ratio of the display period of the image signal within the one frame period.

  Further, the ratio of the display period of the image signal within the one frame period is varied based on the video source selection instruction information input by the user.

  Furthermore, the ratio of the display period of the image signal within the one frame period is varied based on the video adjustment instruction information input by the user.

  According to the liquid crystal display device of the present invention, when the backlight light source is intermittently driven to prevent motion blur, the backlight lighting period is determined according to the type of image content to be displayed or according to a user instruction. That is, by appropriately switching the ratio (impulse rate) of the image display period within one frame period, it is possible to appropriately suppress image quality degradation due to various factors such as motion blur, stroboscopic and flicker. Image quality can be improved.

  Similarly, even when motion blur is prevented by writing a black display signal to the liquid crystal display panel, the black display period, that is, one frame is determined according to the type of image content to be displayed or according to a user instruction. By appropriately switching the ratio of the image display period (impulse rate) within the period, it is possible to appropriately suppress image quality deterioration due to various factors such as motion blur, stroboscopic and flicker, and improve overall image quality. Can be realized.

  The liquid crystal display device according to the present invention prevents motion blur that occurs when displaying a moving image by bringing it closer to an impulse display, and is suitable for a liquid crystal television, a computer monitor, and the like.

It is a functional block diagram which shows the principal part schematic structure in the conventional liquid crystal display device (entire flash type). It is explanatory drawing which shows the display response in the conventional liquid crystal display device (full-flash type). It is explanatory drawing which shows the example of arrangement | positioning of the backlight light source with respect to the liquid crystal display panel in the conventional liquid crystal display device (scanning type). It is explanatory drawing which shows an example of the lighting / extinguishing timing of each lamp in the conventional liquid crystal display device (scanning type). It is explanatory drawing which shows the other example of the lighting / extinguishing timing of each lamp | ramp in the conventional liquid crystal display device (scanning type). (A), (b) It is a schematic explanatory drawing which shows the display operation principle of the impulse type display by a black writing type | mold, (c) The display operation principle of a hold type display. It is a schematic explanatory drawing for demonstrating the kind of image content from which the additional amount of a motion blur differs. It is a functional block diagram which shows the principal part schematic structure in 1st Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating an example of the basic operation principle in 1st Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the other example of the basic operation principle in 1st Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating an example of the basic operation principle in 2nd Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the other example of the basic operation principle in 2nd Embodiment of the liquid crystal display device of this invention. It is a functional block diagram which shows the principal part schematic structure in 3rd Embodiment of the liquid crystal display device of this invention. It is a timing chart for demonstrating the electrode drive operation | movement in 3rd Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 3rd Embodiment of the liquid crystal display device of this invention. It is a functional block diagram which shows the principal part schematic structure in the liquid crystal display device of the 4th Embodiment of this invention. It is a functional block diagram which shows the electrode drive part of the 4th Embodiment of this invention. It is a schematic explanatory drawing which shows the example of the content of the reference | standard gradation voltage data storage part in the liquid crystal display device of this invention. It is explanatory drawing which shows an example of the relationship of the transmittance | permeability with respect to the applied voltage of a liquid crystal. 4 is a schematic explanation showing response characteristics of liquid crystal in the liquid crystal display device of the present invention. It is a block diagram which shows schematic structure of the reference | standard gradation voltage generation part in the liquid crystal display device of this invention. It is a circuit diagram which shows the principal part schematic structure of the signal line drive circuit in the liquid crystal display device of this invention. It is a schematic explanatory drawing which shows the gamma characteristic at the time of a hold type display and an impulse type display in the liquid crystal display device of this invention. It is a functional block diagram which shows the principal part schematic structure in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing which shows the switching operation example of the impulse rate in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing which shows the example of a switching setting screen of the impulse rate in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 6th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 6th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 6th Embodiment of the liquid crystal display device of this invention. It is a functional block diagram which shows the principal part schematic structure in 7th Embodiment of the liquid crystal display device of this invention. It is a timing chart for demonstrating the electrode drive operation | movement in 7th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing for demonstrating the basic operation principle in 7th Embodiment of the liquid crystal display device of this invention. It is a functional block diagram which shows the principal part schematic structure in 8th Embodiment of the liquid crystal display device of this invention. It is a functional block diagram which shows the electrode drive part of the 8th Embodiment of this invention. It is a characteristic view which shows the relationship between the external light illumination intensity and display brightness in the use environment in the liquid crystal display device of this invention. It is a characteristic view which shows the relationship between the response time and temperature in the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Demultiplexing part 2 Image decoding part 3 Frame frequency conversion part 4 Gradation conversion part 5 Electrode drive part 6 Liquid crystal display panel 7 Backlight light source 8 Light source drive part 9 Synchronization signal extraction part 10 Control CPU
13 Frame frequency conversion unit 14 Gradation conversion unit 15 Electrode drive unit 16 Liquid crystal display panel 17 Backlight source 18 Light source drive unit 19 Synchronization signal extraction unit 20 Control CPU
21 Remote receiver

Claims (6)

A liquid crystal display device in which a display period and a non-display period of an image signal to be displayed are provided within one frame period,
Means for on-screen display of an impulse rate setting screen for setting a ratio of the display period of the image signal within the one frame period;
A liquid crystal display device comprising: means for variably controlling a ratio of a display period of the image signal within the one frame period based on selection instruction information of an impulse rate by a user.   The means for variably controlling the ratio of the display period of the image signal within the one frame period variably controls the lighting time of the backlight light source disposed on the back surface of the liquid crystal display panel. The liquid crystal display device according to claim 1.   The means for variably controlling the ratio of the display period of the image signal within the one frame period is light of a shutter means provided between the backlight source disposed on the back surface of the liquid crystal display panel and the liquid crystal display panel. 2. The liquid crystal display device according to claim 1, wherein the transmission period is variably controlled.   The means for variably controlling the ratio of the display period of the image signal within the one frame period variably controls the period during which the voltage applied to the liquid crystal display panel is held based on the image signal. The liquid crystal display device according to claim 1.   5. The liquid crystal display device according to claim 1, wherein a gradation level of the input image signal is varied in accordance with a ratio of the display period of the image signal within the one frame period. According to the ratio of the display period of the image signal within the one frame period,
5. The liquid crystal display device according to claim 1, wherein a gradation voltage applied to the liquid crystal panel is varied in accordance with an input image signal.

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