JP2013186270A - Backlight controlling apparatus, backlight controlling method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a high quality image.SOLUTION: A timing controller 24 performs control to cause a backlight to emit light at first brightness for a first time in a period that original image data is displayed on a liquid crystal panel 27, and cause the backlight to emit light at second brightness darker than the first brightness for a second time longer than the first time in a period that intermediate image data generated on the basis of the original image data is displayed on the display device.

Description

  The present invention relates to a technique for controlling a backlight used in a display device that displays image data.

  Conventionally, when original image data and intermediate image data are alternately displayed at the same brightness on a liquid crystal display device, the intermediate image data is not completely created, so that the disturbed portion of the intermediate image data has become conspicuous. On the other hand, in the technique disclosed in Patent Document 1, since the original image data is brightly emitted and the intermediate image data is darkly emitted, the disturbed portion is slightly inconspicuous. In the technique disclosed in Patent Document 2, light is emitted such that the original image data is lengthened and the intermediate image data is shortened.

JP 2008-070838 A JP 2008-0083457 A

  However, apart from the problem of disturbance of the intermediate image data, there is a problem of occurrence of flicker. As in the conventional example described above, flickering occurs when the image is made up of two types of brightness and darkness. Therefore, if the brightness difference is increased, the flickering becomes stronger and the viewer becomes difficult to see. Therefore, there is a limit to the difference between light and dark. In addition, a phenomenon in which the peripheral portion of the display object appears to flicker due to the difference in shape between the original image data and the intermediate image data. Furthermore, as another problem, when the original image data is lighted for a long time to make it brighter, the image is blurred in spite of the generation of the intermediate image data in the moving display part. It looks like an image.

  Therefore, an object of the present invention is to perform high-quality image display.

  The backlight control device of the present invention is a backlight control device that controls a backlight used in a display device that displays image data, and the first brightness is displayed during a period in which the original image data is displayed on the display device. In the first time, the backlight is turned on, and the intermediate image data generated based on the original image data is displayed on the display device at a second brightness that is darker than the first brightness. Control means for controlling the backlight to emit light for a second time longer than the first time is provided.

  According to the present invention, high-quality image display can be performed.

It is a figure for demonstrating how a various image looks. It is a figure which shows the structure of the display apparatus which concerns on embodiment of this invention. It is a figure which shows the light emission state of the backlight in the 1st Embodiment of this invention. It is a figure which shows the mode of the electric current which flows into LED. It is a figure for demonstrating the operation | movement of the backlight scan in the 2nd Embodiment of this invention. It is a figure for demonstrating the operation | movement which combined the brightness of the image and the time control of a backlight in the 3rd Embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments to which the invention is applied will be described in detail with reference to the accompanying drawings.

  First, how various images are seen will be described with reference to FIG. FIG. 1A shows how the 60 Hz display with impulse light emission is viewed. FIG. 1B shows the appearance of 60 Hz display in which the backlight is hold-emitted and black is inserted. FIG. 1 (C) shows how the 120 Hz display is viewed with the backlight turned on and off to give light and darkness. FIG. 1D shows the appearance of 120 Hz display in which the backlight emits impulse light and is brightened and darkened. FIG. 1E shows the appearance of 120 Hz display by backlight emission in the embodiment of the present invention.

  In FIG. 1, the object displayed on the liquid crystal panel is spherical, and is an object that moves from right to left for each frame. The vertical axis in FIG. 1 represents time. In the case of 60 Hz display, the image data is switched every 16.67 ms. In FIG. 1, the movement of the line of sight is indicated by an arrow. Image data (image data visible to the viewer) synthesized along the movement of the line of sight is shown at the bottom.

  In FIG. 1A, reference numeral 111 denotes the shape of an object that can be seen in one frame by impulse-like light emission. Reference numeral 112 denotes an object shape that can be seen by combining several frames by impulse-like light emission. In FIG. 1B, reference numeral 113 denotes the shape of an object that can be seen in one frame by hold-type light emission. Reference numeral 114 denotes the shape of an object that can be seen by combining several frames by holding-like light emission. In FIG. 1C, reference numeral 115 denotes the shape of an object that can be seen in the frame of the original image data by holding bright light emission (bright light emission). Reference numeral 116 denotes the shape of an object that can be seen in the frame of the intermediate image data by hold-type dark light emission (dark light emission). Reference numeral 117 denotes the shape of an object that can be seen by combining several frames by holding light emission. In FIG. 1D, reference numeral 118 denotes the shape of an object that can be seen within the frame of the original image data due to impulse bright light emission. Reference numeral 119 denotes the shape of an object that can be seen in the frame of the intermediate image data due to impulse-like dark light emission. Reference numeral 120 denotes the shape of an object that can be seen by combining several frames by impulse-like light emission. In FIG. 1E, reference numeral 121 denotes the shape of an object that can be seen in the frame of the original image data by impulse bright light emission in the present embodiment. Reference numeral 122 denotes the shape of an object that can be seen in the frame of the intermediate image data by hold-type dark light emission in the present embodiment. Reference numeral 123 denotes the shape of an object that can be seen by combining several frames by light emission in the present embodiment.

  In the example of FIG. 1 (A), only the original image data is displayed for each frame by impulse-like light emission, so the appearance of the object is close to a sphere as shown by 111 and appears to be composed of several frames. The object also looks a little elliptical as shown at 112, but is nearly spherical. Therefore, although the appearance with respect to the movement of the object is the best, flicker is generated when the impulse-like light emission display is performed at 60 Hz, so that it cannot be displayed brightly.

  In the example of FIG. 1B, only original image data is displayed for each frame by hold-type light emission. The light emission time becomes longer as indicated at 113. When this is combined with several frames in the movement direction of the line of sight, the object appears to be deformed into an ellipse as shown at 114. Since black is inserted and the hold light emission time is halved, the degree is slightly improved but deformed. If the black insertion time is made longer, the deformation is improved. However, since the light emission is impulse-like, the flicker is severely generated as in the example of FIG.

  In order to prevent flicker, an example in which intermediate image data is generated and displayed at 120 Hz is shown below. In the example of FIG. 1C, the shape of the object that can be seen by holding bright light emission with respect to the original image data is 115. The shape of the object that can be seen by hold-type dark light emission with respect to the intermediate image data is 116, which is an ellipse that has collapsed due to an intermediate image data generation error. The shape of the object that appears by combining them according to the movement of the line of sight is 117, and the ellipse and the broken ellipse are alternately displayed, so that the periphery of the ellipse appears to flicker.

  In the example of FIG. 1D, impulses are emitted so that an object looks spherical. In FIG. 1D, the shape of the object that can be seen by impulse bright light emission is 118 with respect to the original image data, and it looks almost spherical because of the impulse light emission. In addition, the shape of the object that can be seen by impulse-like dark light emission with respect to the intermediate image data is 119, and it is a spherical shape that has been destroyed due to a generation error in the intermediate image data. The shape of the object seen by combining them according to the movement of the line of sight is close to a sphere as shown at 120, but due to a mistake in the conversion of the intermediate image data, the periphery of the sphere will still appear to flicker. .

  FIG. 1E shows an example of how an object looks in the present embodiment. In the example of FIG. 1E, the shape of an object that can be seen by impulse bright emission with respect to the original image data is 121, and it looks almost spherical because of impulse emission. In addition, the shape of the object that can be seen by holding dark light emission with respect to the intermediate image data is 122, which is an ellipse that has collapsed due to a generation error in the intermediate image data. The shape of the object seen by combining them according to the movement of the line of sight is 123.

  This synthesized shape is a dark spherical image connected to a bright spherical image. That is, the same shape as the moving shape looks bright, and a dark image such as a tail appears behind. The appearance of 123 does not change its shape like 114 and 117, and the periphery of the main body does not flicker like 117 and 120. Although a dark tail can be seen, it is natural and easy for a viewer to perceive the movement of an object on a display device.

  FIG. 2 is a diagram showing the configuration of the display device according to the first embodiment of the present invention. Note that a backlight based on backlight scanning using LEDs is applied to the display device according to the present embodiment. Note that the display device according to the present embodiment has a configuration as an application example of the backlight control device.

  In FIG. 2, reference numeral 21 denotes an image quality adjustment circuit that adjusts the image quality of the image signal (image data) in accordance with the display device and viewer settings. A frame frequency conversion circuit 22 creates intermediate image data of one or more frames between frames of the original image data. A frame memory 23 temporarily stores frame image data. A timing controller 24 controls and adjusts the timing of the panel module and the backlight module. Reference numeral 25 denotes a source driver for driving the liquid crystal panel. Reference numeral 26 denotes a gate driver for driving the liquid crystal panel. Reference numeral 27 denotes a liquid crystal panel.

  Reference numeral 31 denotes a first current setting value for determining a current when the LED is brightly illuminated. Reference numeral 32 denotes a second current setting value for determining a current for causing the LED to shine darkly. Reference numeral 33 denotes an analog selector that switches between the two types of current setting values. Reference numeral 34 denotes an analog switch array for switching the LEDs on and off. Reference numeral 35 denotes a driver for driving the LED. Reference numeral 36 denotes LEDs arranged in the left and right direction. Reference numeral 37 denotes LEDs arranged in the right and up direction. Reference numeral 38 denotes a light guide plate that guides light from the left and right LEDs in a streak shape.

  Next, the operation of the display device according to the present embodiment will be schematically described. The image quality adjustment circuit 21 adjusts the image quality of the input image signal (YpbPr signal) using the characteristics of the liquid crystal panel 27 and the viewer's preference as parameters, thereby outputting an RGB signal corresponding to the optimum image.

  Next, the frame frequency conversion circuit 22 uses the frame memory 23 as a temporary storage area, and generates intermediate image data by known vector estimation from the original image data for two frames. When the frequency is increased from 60 Hz to 120 Hz, one piece of intermediate image data is generated between two frames, but when it is increased to 240 Hz, three pieces of intermediate image data are generated between two frames.

  Next, the RGB signal raised to 120 Hz is input to the timing controller 24. At this time, a signal indicating whether the input RGB signal is an original image data signal or an intermediate image data signal is also input to the timing controller 24 at the same time.

  Next, the timing controller 24 gives gradation data obtained by converting the RGB signal into a digital value indicating a voltage to the source driver 25 of the liquid crystal panel 27 and scans the gate driver 26 at 60 Hz. Give a timing signal. Then, the source electrode and the gate electrode of the liquid crystal panel 27 are driven by the gate driver and the source driver, and the common electrode (not shown) is also driven to display the image data on the screen.

  Next, the operation of the backlight module in the display device according to the present embodiment will be described. The timing controller 24 outputs voltage values corresponding to the first current set value 31 and the second current set value 32 using an internal DA converter. For example, if the current value during bright light emission of the LEDs 36 and 37 is 20 mA, the first current setting value 31 is set to 2V. On the other hand, if the current during dark emission is 4 mA, the second current set value 31 is set to 0.4V.

  The frame frequency conversion circuit 22 outputs a signal indicating which of the original image data and the intermediate image data is being output. The analog selector 33 inputs the signal from the frame frequency conversion circuit 22 and switches between the first current set value 31 and the second current set value 32 and outputs them. Here, the first current set value is output during the period when the original image data is displayed, and the second current set value is output during the period when the intermediate image data is displayed.

  The timing controller 24 controls the scan operation for the analog switch array 34. The scan operation is a control for sequentially shifting the output value of the analog selector 33 from the ON state of the upper analog switch to the OFF state of the lower analog switch. In addition, the timing controller 24 controls the time for which each analog switch is ON so that the time is different between the original image data and the intermediate image data, that is, the ON time in the original image data is shortened, Increase the ON time in the image data.

  Each current set value that is ON / OFF controlled by the analog switch array 34 is converted into a current value (20 mA or 4 mA) by the LED driver 35 and supplied to the left LED 36 and the right LED 37. The left LED 36 and the right LED 37 to which the current is supplied emit bright light or dark light according to the current value (20 mA or 4 mA). The light of the left LED 36 and the right LED 37 is guided in a horizontal stripe shape by the light guide plate 38, and the front surface of the light guide plate 38 shines in a strip shape. As a result, the image on the liquid crystal panel 27 is displayed as if it is being scanned by the backlight.

  FIG. 3 is a diagram showing a light emission state of the backlight in the present embodiment. That is, FIG. 3A shows a state in which the light emission state transitions with time. FIG. 3B shows a relationship between time and luminance in a line near the center.

  In FIG. 3A, reference numeral 41 denotes a backlight state when the original image data is displayed in the first half. Reference numeral 42 denotes a backlight state when the original image data is displayed in the latter half. Reference numeral 43 denotes a backlight state when the first half of the intermediate image data is displayed. Reference numeral 44 denotes a backlight state at the time of displaying the second half of the intermediate image data. 45 is bright and short time light emission. 46 is dark and long time light emission. In FIG. 3B, reference numeral 47 denotes a luminance change of a line near the center when the original image data is displayed. Reference numeral 48 denotes a luminance change of a line near the center when the intermediate image data is displayed. The light emission 45 is an example in which light emission is performed for the first time at the first brightness, and the light emission 46 is second brightness that is darker than the first brightness and longer than the first time. This is an example of light emission.

  In FIG. 3A, the backlight state transitions from 41 to 42, 42 to 43, 43 to 44, and 44 to 41. At this time, the light emission 45 of bright and short time scans from the top to the bottom, and the light emission 46 of dark long time scans from top to bottom so as to follow the light.

  In relation to the liquid crystal panel, the original image data is displayed from a little before 41 to a little after 42, while a bright thin line is scanned from top to bottom. The time when the intermediate image data is displayed is from a little before 46 to a little after 47, while a dark and thick line is scanned from top to bottom.

  If attention is paid to a certain line, the original image data is emitted for a short time with a high luminance like 47. In the case of intermediate image data, light is emitted for a long time with a low luminance like 48. By combining such a backlight emission pattern with the display state of the original image data and intermediate image data on the liquid crystal panel 27, a moving object as shown in FIG. 1E can be seen.

  FIG. 4 is a diagram illustrating a state of current flowing through the LEDs 36 and 37. The horizontal axis of FIG. 4 is obtained by swinging the numbers of the LEDs 36 and 37 from top to bottom (from 1 to 11). For ease of explanation, the number of LEDs 36 and 37 is 11 respectively, but the number is larger in the case of a large screen backlight. The vertical axis represents the current value.

  The current flowing through the LEDs 36 and 37 transitions from M1, M2 to M11, S1, and S2 to S14 with time. Since there is a pause period between M11 and S1 and between S14 and M1, in the case of a 60 Hz image signal, one period corresponds to 16.67 ms, and each state is about 0.6 ms. The original image data is displayed between M1 and M11, and the intermediate image data is displayed between S1 and S14.

  In M1, the uppermost LED (1) is lit brightly. When transitioning to M2, LED (1) is turned off and LED (2) is turned on brightly. The transition is continued so as to scan downward in order, and the lowermost LED (11) is reached at M11. During the rest period thereafter, all the LEDs are turned off.

  In S1, the uppermost LED (1) is lit dark. If it changes to S2, LED (2) will also be lit darkly with LED (1) lit. Transition is made while increasing the number of LEDs that are lit until S3 and S4. In S5, the LED (1) is turned off and the LED (5) is turned on darkly. After S6, similarly, one is turned off and a transition is made so that only one LED is lit at S14. During the rest period thereafter, all the LEDs are turned off. By controlling the LED current value and the ON time in this way, the backlight emission pattern as shown in FIG. 3 can be obtained.

  It should be noted that the center of the light emission period of the original image data and the center of the light emission period of the intermediate image data need to have substantially the same phase within each frame. This is because when the phase is shifted, the components of the 60 Hz period as a whole increase in spite of the 120 Hz period, and flicker occurs.

  The present invention is not limited to the above-described embodiments, and can be configured in other embodiments in which the elements of the invention are the same. For example, it is desirable from the viewpoint of flicker that the luminance of the original image data and the luminance of the intermediate image data are the same. Note that the luminance here means a luminance value obtained by integrating pulsed repeated light emission over a long time.

In the range where the light emission intensity of the LED is proportional to the current value, the luminance is equalized by changing the current value for intermediate image data in the first embodiment from 4 mA to 5 mA. Alternatively, the luminance is approximately equal by setting the light emission time of the intermediate image data to five times the light emission time of the original image data.
Luminance of original image data: Brightness of intermediate image data = 1: 1

However, it is desirable to reduce the brightness of the intermediate image data within the flicker tolerance range because the tailing is reduced. This luminance ratio varies depending on the display luminance, but is generally in the following range.
Luminance of the original image data: Luminance of the intermediate image data = 1: 1 luminance to 4: 1 luminance The luminance of the intermediate image data is ¼ or more of the luminance of the original image data.

Further, from the viewpoint of the cost of the LED, since it is expensive to emit light brightly in a short time, the cost is reduced by making the luminance of the original image data darker than the luminance of the intermediate image data. It is practical in the following ranges.
Luminance of original image data: Luminance of intermediate image data = 1: 1 to 1: 2
The brightness of the intermediate image data is less than twice the brightness of the original image data

Next, the number of frames of the intermediate image data need not be the same as the number of frames of the original image. In order to display more smoothly, it is desirable to increase the number of frames of the intermediate image data, but the intermediate image data of the moving object is blurred. For this reason, if the number of frames of the intermediate image data is large, tailing increases, so it is important not to increase the number of frames of the intermediate image data too much. It is practical in the following ranges.
Number of frames of original image data: Number of frames of intermediate image data = 1: 1 to 1: 3

  Next, the backlight method is described. In the first embodiment, the scanning method using the left and right LED arrangements has been described. However, it is a matter of course that a scanning method using a direct type LED backlight may be used. Furthermore, if the direct type is used, each LED block can be independently controlled according to the luminance distribution of the image data, and the luminance distribution can be changed, so that the dynamic contrast is improved. In this case, for each LED, both the emission intensity for the original image data and the emission intensity for the intermediate image data are controlled.

  Further, the present invention is not limited to the scan method, and can be applied in the same manner as the scan method by simultaneously flashing the entire surface of the backlight in the method of simultaneously emitting light on the entire surface. As in the first embodiment, the amount of light and the time for illuminating the entire backlight may be lit for a short time for the original image data and light for the long time for the intermediate image data.

  Next, a second embodiment of the present invention will be described. In the second embodiment of the present invention, a case where light emission with a small duty ratio is performed on intermediate image data using a device that intermittently emits light such as an LED will be described. The configuration of the display device according to the second embodiment is the same as the configuration of the display device according to the first embodiment shown in FIG. Hereinafter, only differences from the first embodiment will be described.

  FIG. 5 is a diagram for explaining the operation of the backlight scan in the second embodiment of the present invention. FIG. 5A shows transition of the light emission state over time. FIG. 5B shows a relationship between time and luminance in a line near the center. FIG. 5C shows the relationship between the position of the viewer on the retina and the visible brightness.

  In FIG. 5A, reference numeral 241 denotes a backlight state when the original image data is displayed in the first half. Reference numeral 242 denotes a backlight state when the latter half of the original image data is displayed. Reference numeral 243 denotes a backlight state when the first half of the intermediate image data is displayed. Reference numeral 244 denotes a backlight state when the intermediate image data is displayed in the latter half. Reference numeral 245 denotes bright light emission for a short time. Reference numeral 246 denotes bright and numerous light emission. In FIG. 5B, reference numeral 247 denotes a luminance change of a line near the center when displaying the original image data. Reference numeral 248 denotes a luminance change of the line near the center when the intermediate image data is displayed. Reference numeral 249 denotes a distribution of projected brightness on the retina when the original image data is displayed. Reference numeral 250 denotes a distribution of projected brightness on the retina when displaying the original image data.

  In FIG. 5A, the backlight state transitions from 241 to 242, 242 to 243, 243 to 244, and 244 to 241 repeatedly. At this time, light emission 245 for a short time is brightly scanned from top to bottom, and light emission 246 with many numbers is repeatedly scanned from top to bottom so as to follow.

  In relation to the liquid crystal panel, the period during which the original image data is displayed is from a little before 241 to a little after 242, and while a bright thin line is scanned from top to bottom. The period during which the intermediate image data is displayed is from a little before 246 to a little after 247, while a plurality of bright and thin lines are scanned from top to bottom.

  If attention is paid to a certain line, light is emitted at high brightness for a short time as indicated by 247 when the original image data is displayed. The same brightness is displayed when displaying the intermediate image data, but the light is emitted many times in a very short time. When an object moving in the left-right direction is followed, the pixels of the liquid crystal panel 27 appear to flow on the retina. In the case of impulse-like light emission such as H.245, the pixel shines only for a moment, so that only the position on the retina where the pixel at that time appears is shown as indicated by 249. In a plurality of times of light emission as shown by H.246, the pixel positions at that time exist a plurality of times, so that they are visually averaged and spread laterally as shown by 250.

  Combining such a backlight emission pattern with the display state of the original image data and intermediate image data on the liquid crystal panel 27 makes it possible to see a moving object as shown in FIG.

  In the second embodiment, the same effect can be obtained by extremely reducing the duty ratio of light emission at the time of displaying intermediate image data even in control only in the time direction without controlling the light emission intensity of the LED. It is possible to put out. Similarly, even if the light emission at the time of displaying the original image data is a high duty intermittent light emission, the same effect can be obtained because it is averaged visually.

  Next, a third embodiment of the present invention will be described. In the third embodiment of the present invention, a case where the lamp is difficult to control brightness such as CCFL (Cold Cathode Tube) will be described. The configuration of the display device according to the third embodiment is the same as the configuration of the display device according to the first embodiment shown in FIG. Hereinafter, only differences from the first embodiment will be described.

  FIG. 6 is a diagram for explaining an operation in which image contrast and backlight time control are combined in the third embodiment of the present invention. That is, FIG. 6A shows the transition of the display state on the liquid crystal panel 27 alone. FIG. 6B shows a light emission display state with a backlight. FIG. 6C shows the relationship between the passage of time and the amount of light of the backlight. FIG. 6D shows the relationship between the passage of time and the light emission display luminance.

  In FIG. 6A, reference numeral 261 denotes a first frame of original image data. Reference numeral 262 denotes a first frame of intermediate image data. Reference numeral 263 denotes a second frame of the original image data. H.264 is a moving object in the original image data. Reference numeral 265 denotes a moving object in the intermediate image data. In FIG. 6B, reference numeral 267 denotes a light emission display state when the backlight is turned off. Reference numeral 268 denotes a light emission display state when the backlight emits light for a short time. Reference numeral 269 denotes a light emission display state when the backlight emits light for a long time. In FIG. 6C, reference numeral 271 denotes the time lapse of the backlight light amount when displaying the original image data. Reference numeral 272 denotes a time lapse of the backlight light amount when the intermediate image data is displayed. Reference numeral 273 denotes a luminance time passage when displaying the original image data. Reference numeral 272 denotes a luminance time lapse when the intermediate image data is displayed.

  As indicated by reference numeral 265 in FIG. 6A, the frame frequency conversion circuit 22 sets the gradation of the intermediate image data lower than the original image data. As indicated by reference numerals 271 and 272 in FIG. 6C, the backlight is lit with a uniform amount of light without lighting. As a result, in the period indicated by 271, the original image data is brightly displayed in a short time as indicated by 268 and is indicated by 273. In the period indicated by 272, the intermediate image data is darkly displayed for a long time as indicated by 269, and is indicated by 274. As a result, the same characteristics as in FIG. 1 can be obtained, so that the present invention can be applied to a backlight in which the light amount cannot be adjusted.

  In the embodiment described above, when displaying a moving image, the original image data with good image quality appears as an image with less moving image blur, and the intermediate image data with poor image quality appears blurred. Therefore, when both are viewed together, it is possible to obtain a moving image display that is clear but less disturbing. Further, since the intermediate image data has a luminance close to that of the original image data, the occurrence of flicker can be suppressed. Of course, the intermediate image data is generated correctly in the still image data, so that high-quality image display can be performed.

  Note that the present invention can be widely used as long as the display uses a backlight, such as a TV receiver, a Duna separate monitor, and a PC monitor.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

  21: Image quality adjustment circuit, 22: Frame frequency conversion circuit, 23: Frame memory, 24: Timing controller, 25: Gate driver, 26: Source driver, 27: Liquid crystal panel, 31: First current set value, 32: Second Current setting value, 33: analog selector, 34: analog switch array, 35: driver, 36, 37: LED, 38: light guide plate

Claims (12)

A backlight control device that controls a backlight used in a display device that displays image data,
The display device emits a backlight for a first time at a first brightness during a period in which the original image data is displayed, and intermediate image data generated based on the original image data is displayed on the display device. And a control means for controlling the backlight to emit light for a second time longer than the first time at a second brightness that is darker than the first brightness for a period of time. apparatus.   The backlight control apparatus according to claim 1, wherein the control unit controls the backlight so that the luminance of the original image data is substantially equal to the luminance of the intermediate image data.   The backlight control apparatus according to claim 1, wherein the control unit controls the backlight so that the luminance of the intermediate image data is equal to or higher than one-fourth of the luminance of the original image data.   The backlight control apparatus according to claim 1, wherein the control unit controls the backlight so that the luminance of the intermediate image data is not more than twice the luminance of the original image data.   The backlight control apparatus according to claim 1, wherein the number of frames of the intermediate image data is 1 to 3 times the number of frames of the original image data.   6. The backlight control apparatus according to claim 1, wherein the control unit controls the backlight by a scanning method.   6. The backlight control apparatus according to claim 1, wherein the control unit independently controls each block in the direct type backlight.   The backlight control apparatus according to claim 1, wherein the control unit causes the entire backlight to blink simultaneously.   The control means controls to emit light intermittently in at least one of light emission at the first brightness and light emission at the second brightness. The backlight control device according to any one of 1 to 5. The display device further comprises display control means for displaying the gradation of the intermediate image data lower than the original image data.
The backlight control apparatus according to claim 1, wherein the control unit causes the backlight to emit light with a uniform light amount. A backlight control method executed by a backlight control device that controls a backlight used in a display device that displays image data,
The display device emits a backlight for a first time at a first brightness during a period in which the original image data is displayed, and intermediate image data generated based on the original image data is displayed on the display device. A control step of controlling the backlight to emit light for a second time longer than the first time at a second brightness that is darker than the first brightness for a period of time Method. A program for causing a computer to execute a backlight control method executed by a backlight control device that controls a backlight used in a display device that displays image data,
The display device emits a backlight for a first time at a first brightness during a period in which the original image data is displayed, and intermediate image data generated based on the original image data is displayed on the display device. A program for causing a computer to execute a control step of controlling the backlight to emit light for a second time longer than the first time at a second brightness that is darker than the first brightness for a period of time.

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