Display control device and method, and program

Abstract

The present technology relates to a display control device, method, and program that make it possible to reduce video blur even in a state in which the input frequency fluctuates. This display control device is configured so that in blinking control, a normal lighting control period for a backlight is set to be equal to or less than the frame period at the maximum frequency of a video signal, and a luminance reduction amount in an additional lighting control period for the backlight occurring due to frequency fluctuation in the video signal is compensated for by the additional lighting control period and / or the normal lighting period of the next frame. The present technology can be applied to a display device that performs blinking control.

Description

Display control device, method, and program

[0001] The present technology relates to a display control device, method, and program, and in particular to a display control device, method, and program that are capable of reducing image blur even when the input frequency fluctuates.

[0002] Image blur can be reduced by controlling the blinking of the backlight.

[0003] For example, Patent Document 1 proposes a technique for controlling the blinking frequency in accordance with the amount of motion in a video.

[0004] Japanese Patent Application Laid-Open No. 2016-123122

[0005] However, in the blinking control of the backlight, the on and off times of the backlight are determined on the assumption that the input frequency (frame frequency at the time of input) of the video signal is constant. This is also true in the technology of Patent Document 1.

[0006] Therefore, when the input frequency of the video signal fluctuates, it is difficult to respond to the blinking control of the backlight.

[0007] The present technology has been made in view of such circumstances, and makes it possible to reduce image blur even when the input frequency of a video signal fluctuates.

[0008] A display control device according to one aspect of the present technology includes a backlight control unit that, in blinking control, sets a normal lighting control period of a backlight to be equal to or less than a frame period at a maximum frequency of a video signal, and compensates for a reduction in luminance during an additional lighting control period of the backlight caused by frequency fluctuations of the video signal, in at least one of the additional lighting control period and the normal lighting period of a next frame.

[0009] In one aspect of the present technology, in blinking control, a normal lighting control period of a backlight is set to be equal to or less than a frame period at a maximum frequency of a video signal, and a reduction in luminance during an additional lighting control period of the backlight caused by frequency fluctuations of the video signal is compensated for by at least one of the additional lighting control period and the normal lighting period of the next frame.

[0010] 1 is a diagram showing an example of a conventional blinking operation; FIG. 2 is a diagram showing an example of a blinking operation of the present technology; FIG. 3 is a block diagram showing an example of a configuration of a display device according to an embodiment of the present technology; FIG. 4 is a block diagram showing an example of a configuration of the video display processing unit of FIG. 3 together with a display unit; FIG. 5 is a diagram showing an example of an operation of blinking operation mode 1, continuing from FIG. 5; FIG. 6 is a diagram showing another example of an operation of blinking operation mode 1 of FIG. 5; FIG. 7 is a diagram showing an example of an operation of blinking operation mode 2, continuing from FIG. 8; FIG. 8 is a diagram showing an example of an operation of blinking operation mode 3, continuing from FIG. 10; FIG. 9 is a diagram showing an example of an operation of blinking operation mode 4, continuing from FIG. 12; FIG. 11 is a diagram showing another example of an operation of blinking operation mode 4 of FIG. 12; FIG. 13 is a flowchart illustrating backlight control processing of the video display processing unit of FIG. 4; FIG. 4 is a block diagram showing an example of the configuration of a computer.

[0011] Hereinafter, embodiments of the present technology will be described in the following order: 1. Overview of the present technology 2. Configuration 3. Details of blinking operation mode 4. Operation 5. Other

[0012] 1. Overview of the Present Technology Conventional Example of Blinking Operation for the Present Technology FIG. 1 is a diagram showing a conventional example of blinking operation.

[0013] FIG. 1 shows the normal lighting control period T, the light-off period K caused by the frequency fluctuation, and the luminance state when the input frequency of the video signal (frame frequency at the time of input) fluctuates from 120 Hz to 60 Hz in frame m when the blinking ratio is 50%.

[0014] Conventionally, the backlight normal lighting control period T is equal to the frame period of the input frequency and is a period during which the backlight is turned on and off according to the blinking ratio. The backlight off period K is a period during which the backlight is turned off.

[0015] The blinking ratio represents the ratio between the period during which the backlight is ON (hereinafter referred to as the backlight ON period) and the period during which the backlight is OFF (hereinafter referred to as the backlight OFF period) during the normal illumination control period T. In the case of FIG. 1, the blinking ratio is 50%. That is, blinking control is performed so that the backlight is ON for half the period of the normal illumination control period T and OFF for half the period of the normal illumination control period T. Note that when the blinking ratio is 100%, blinking control is performed so that the backlight is ON for the entire normal illumination control period T.

[0016] In Figure 1, the horizontal axis represents time, and the vertical axis represents brightness at each time. During the backlight ON period (effectively the ON period) of the normal illumination control period T, the brightness is 100%, and during the backlight OFF period and the extinguishing period K of the normal illumination control period T, the brightness is 0%. The brightness for each frame and the ON / OFF status of the backlight are also shown at the bottom of the figure.

[0017] In FIG. 1, up to frame m-1, the input frequency is 120 Hz and the blinking ratio is 50%, so blinking control is performed so that half of the normal lighting control period T (1 / 120 seconds) becomes the backlight ON period of the normal lighting control period, and half of the normal lighting control period T becomes the backlight OFF period of the normal lighting control period.

[0018] However, in frame m, blinking control is performed assuming that the input frequency is 120 Hz, but the input frequency changes to 60 Hz midway through, resulting in an off period K (1 / 60 to 1 / 120 seconds) in which the backlight is turned off in addition to the normal lighting control period T.

[0019] As a result, the brightness in one frame is also 50% up to frame m-1 and from frame m+1 onwards because the blinking ratio is 50%. However, in frame m, the brightness in one frame becomes 25% due to the off period K that occurs.

[0020] When the input frequency of the video signal changes from 60 Hz to 120 Hz in frame m when the blinking ratio is 50%, the backlight OFF period of the normal lighting control period T disappears.

[0021] As described above, in a state where the input frequency of the video signal fluctuates, such as in the VRR (Variable Refresh Rate) mode, when backlight blinking control is performed, the backlight OFF period of the normal lighting control period T may become shorter or, conversely, the extinguishing period K may become longer, so that the actual backlight OFF period is not constant.

[0022] As a result, the ratio of the period when the backlight is ON to the period when it is OFF in each frame is lost, the brightness for each frame changes, and the user perceives this change in brightness for each frame as backlight flicker.

[0023] <About the Present Technology> FIG. 2 is a diagram showing an example of a blinking operation of the present technology.

[0024] 2 shows the normal lighting control period T, the additional lighting control period L, and the current ratio when the backlight is on when the input frequency changes from 120 Hz to 60 Hz in frame m when the blinking ratio is 50%. The current ratio when the backlight is on indicates the ratio of the current based on the current during the backlight ON period when the input frequency is 120 Hz (set as 100%).

[0025] 2, the horizontal axis indicates time, the vertical axis indicates the current ratio to the backlight, and the bottom of the figure indicates whether the backlight is ON or OFF.

[0026] In this technology, even if the input frequency fluctuates, the backlight normal illumination control period T is set to be equal to or shorter than the frame period at the maximum frequency of the video signal so that the backlight does not transition to the next frame midway through the normal illumination control period T, as in the past. In the case of Figure 2, since the maximum frequency of the video signal is 120 Hz, the normal illumination control period T is set to 1 / 120 seconds, which is the frame period when the video signal input frequency is 120 Hz.

[0027] Since the blinking ratio is 50%, blinking control is performed so that half of the normal lighting control period T is the backlight ON period and half of the normal lighting control period T is the backlight OFF period.

[0028] In addition, in the present technology, the period caused by the frequency fluctuation is referred to as an additional lighting control period L. In Fig. 2, the additional lighting control period L is shown as a period during which the backlight is turned off. However, the additional lighting control period L is a period during which the backlight is controlled to be turned on and off according to an operation mode, which will be described later.

[0029] Up to frame m-1, the input frequency is 120 Hz, so no additional lighting control period L occurs. Furthermore, when the input frequency is 120 Hz, the current ratio to the backlight is set to 100% during the backlight ON period of the normal lighting control period T, and the current ratio to the backlight is set to 0% during the backlight OFF period of the normal lighting control period T.

[0030] In frame m, blinking control is performed in the same way as in frame m-1, but because the input frequency changes to 60 Hz midway, an additional lighting control period L (1 / 120 seconds) is generated in addition to the normal lighting control period T (1 / 120 seconds). During the additional lighting control period L in Figure 2, the backlight is controlled to be OFF, as in the conventional case, so the current ratio to the backlight is 0%.

[0031] In the present technology, the amount of reduction in luminance of the backlight due to the additional lighting control period L is compensated for when the backlight is turned on in the next frame m+1, as indicated by arrow P. That is, by setting the current ratio to the backlight to 200% during the backlight ON period of the normal lighting control period T in frame m+1, the amount of reduction in luminance of the backlight due to the additional lighting control period L in frame m caused by the frequency change of the input frequency to 60 Hz is compensated for.

[0032] Furthermore, in frame m+1, the input frequency is also 60 Hz, so like frame m, an additional lighting control period L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period L in frame m+1 is compensated for by setting the current ratio to the backlight to 200% during the backlight ON period of the normal lighting control period T in frame m+2, as indicated by arrow P. In the subsequent frames, the same operation is performed until the input frequency changes.

[0033] As described above, in the blinking control of the present technology, the normal lighting control period is set to be equal to or shorter than the frame period of the maximum frequency of the video signal.

[0034] This prevents the transition to the next frame during the normal lighting control period of the backlight even if the input frequency fluctuates.

[0035] Furthermore, although the additional lighting control period is not uniform due to fluctuations in the input frequency, in the blinking control of the present technology, the amount of luminance reduction during the additional lighting control period is compensated for, for example, when the next frame is turned on. Furthermore, as will be described later, the amount of luminance reduction during the additional lighting control period can also be compensated for, for example, during the additional lighting control period.

[0036] As a result, blinking control that can improve image blur can be realized even in a situation where the input frequency fluctuates.

[0037] 2. Configuration Device Configuration FIG. 3 is a block diagram showing an example of the configuration of a display device according to an embodiment of the present technology.

[0038] The display device 1 in FIG. 3 is configured to include a tuner 11, an HDMI (registered trademark) receiver 12, a video distribution application 13, a selector 14, a video display processing unit 15, and a display unit 16.

[0039] The tuner 11 acquires a desired video signal (stream) from a broadcast wave received by an antenna (not shown), and outputs the signal to the selector 14 .

[0040] The HDMI receiver 12 is an interface that receives a video signal supplied from an external device (not shown), such as a personal computer, a game device, etc. The HDMI receiver 12 outputs the received video signal to the selector 14.

[0041] The video distribution application 13 receives a desired video signal from a video distribution server (not shown) via a network, and outputs the received video signal to the selector 14 .

[0042] The selector 14 selects one of the video signals supplied from the tuner 11, the video signal supplied from the HDMI receiver 12, and the video signal supplied from the video distribution application 13, and outputs the selected video signal to the video display processing unit 15.

[0043] As will be described later, the selector 14 supplies not only the video signal but also a vertical synchronization signal Vsync to the video display processing unit 15 .

[0044] The video display processing unit 15 performs processing such as frame rate conversion on the video signal, and controls the display unit 16 based on the processing results.

[0045] The display unit 16 is configured to include a liquid crystal display panel 21 and a backlight 22 .

[0046] The liquid crystal display panel 21 drives the liquid crystal display elements to modulate the light emitted from the backlight 22, thereby performing display.

[0047] The backlight 22 is configured using, for example, a small LED (Light Emitting Diode) of about 100 μm to 200 μm, or a conventional sized LED or CCFL (Cold Cathode Fluorescent Lamp), and emits surface-emitted light toward the liquid crystal display panel 21. As described above, the backlight 22 repeatedly turns on and off, performing a so-called blinking operation.

[0048] Although the example in FIG. 3 shows the configuration of a display device including a display unit, the present technology can also be applied to a display control device that does not include a display unit as a component.

[0049] <Configuration of Video Display Processing Unit> FIG. 4 is a block diagram showing an example of the configuration of the video display processing unit in FIG. 3 together with a display unit.

[0050] The video display processing unit 15 in FIG. 4 is configured to include a frame buffer 31, a motion vector detection unit 32, a backlight control unit 33, and a display control unit .

[0051] The video signal from the selector 14 is supplied to a frame buffer 31, a motion vector detection unit 32, and a display control unit 34. The vertical synchronization signal from the selector 14 is supplied to a backlight control unit 33 and a display control unit 34.

[0052] The frame buffer 31 holds one frame's worth of frame images included in the supplied video signal, and outputs the previous frame image in the image signal to the motion vector detection unit 32 .

[0053] The motion vector detection unit 32 detects a motion vector indicating a change in the image based on the frame image included in the video signal and the frame image of the immediately previous frame supplied from the frame buffer 31 .

[0054] Specifically, the motion vector detection unit 32 detects horizontal and vertical movement of the display content, for example, in units of blocks each consisting of a plurality of pixels, based on the information of the two supplied frame images, and obtains a motion vector.

[0055] Then, the motion vector detection unit 32 determines an appropriate blinking operation mode from among a plurality of blinking operation modes according to the series of motion vectors obtained on a block-by-block basis, and outputs information indicating the determined blinking operation mode to the backlight control unit 33. For example, at the timing when the amount of motion of the obtained motion vector exceeds a certain set threshold, the motion vector detection unit 32 outputs information indicating the blinking operation mode according to the amount of motion to the backlight control unit 33.

[0056] Based on the supplied vertical synchronization signal Vsync and information indicating the blinking operation mode, the backlight control unit 33 controls the ON and OFF operation of the backlight 22. Specifically, based on the supplied vertical synchronization signal Vsync and information indicating the blinking operation mode, the backlight control unit 33 generates a backlight control signal corresponding to the video signal and outputs the generated backlight control signal to the backlight 22.

[0057] The backlight control signal is a control signal that controls whether the backlight 22 is turned on or off.

[0058] The backlight control unit 33 is configured to include a backlight reference signal generation unit 51, a frequency measurement unit 52, a brightness reduction amount calculation unit 53, and a backlight illumination amount calculation unit .

[0059] The backlight reference signal generating unit 51 generates a backlight reference signal that serves as a reference for the operation of the backlight 22 based on the supplied vertical synchronization signal Vsync, and outputs the generated backlight reference signal to the frequency measuring unit 52 .

[0060] The frequency measurement unit 52 determines the length of the current frame and measures the frequency at the timing when it receives the backlight reference signal supplied from the backlight reference signal generation unit 51. The frequency measurement unit 52 outputs the frequency measurement result to the luminance reduction amount calculation unit 53.

[0061] The brightness reduction amount calculation unit 53 uses the measurement result of the supplied frequency to calculate the brightness reduction amount due to the length of the additional lighting control period, and outputs the calculated brightness reduction amount to the backlight lighting amount calculation unit 54.

[0062] The backlight illumination amount calculation unit 54 calculates the illumination amount of the backlight in the current frame or the illumination amount of the backlight in the next frame based on the information indicating the blinking operation mode supplied from the motion vector detection unit 32, in order to compensate for the brightness corresponding to the supplied amount of brightness reduction.

[0063] The backlight illumination amount calculation unit 54 controls the backlight 22 based on the calculated illumination amount of the backlight.

[0064] Based on the supplied video signal and vertical synchronization signal Vsync, the display control unit 34 controls the display of the liquid crystal display panel 21. Specifically, the display control unit 35 performs predetermined image processing such as gamma processing and overdrive processing on the video signal, and outputs a liquid crystal display control signal to the liquid crystal display panel 21.

[0065] <3. Details of the blinking operation mode> Here, the longer the backlight OFF period, the greater the effect of the blinking operation. However, the longer the backlight OFF period, the lower the brightness becomes, so significant brightness compensation becomes necessary thereafter. The more brightness compensation is required, the more difficult it becomes to accurately reproduce brightness, and flicker becomes a perceived adverse effect of brightness changes. To prevent flicker, it is desirable to avoid brightness compensation as much as possible.

[0066] As such, there is a trade-off between the benefits obtained by blinking operation and the adverse effect of flicker, so this technology provides multiple blinking operation modes and, based on the motion vector of the video signal, determines whether the scene in the video signal is a scene that requires blinking operation or a scene that requires flicker suppression by comparing it with a threshold value, etc., and can dynamically change the blinking operation mode.

[0067] If the input frequency of the video signal is low enough to make flicker more noticeable, or if the frequency of the video signal changes frequently, the blinking operation may be stopped.

[0068] Each blinking operation mode will be explained in turn below.

[0069] <Blinking Operation Mode 1> FIGS. 5 and 6 are diagrams showing an example of operation in blinking operation mode 1. FIG.

[0070] Fig. 5 shows an example of operation in blinking operation mode 1 when the input frequency varies from 240 Hz to 120 Hz. Fig. 6, following Fig. 5, shows an example of operation in blinking operation mode 1 when the input frequency varies from 120 Hz to 80 Hz.

[0071] 5 and 6 show the normal lighting control period T, additional lighting control period L, and current ratio when the backlight is on when the input frequency changes from 240 Hz to 120 Hz in frame m and then from 120 Hz to 80 Hz in frame n when the blinking ratio is 50%. Therefore, in Figures 5 and 6, the normal lighting control period T is less than the frame period when the video signal has the maximum frequency (240 Hz).

[0072] Furthermore, since the blinking ratio is 50%, blinking control is performed so that half of the normal lighting control period T is the backlight ON period and half of the normal lighting control period T is the backlight OFF period.

[0073] 5, the input frequency is 240 Hz up to frame m-1, so no additional lighting control period L occurs. Furthermore, when the input frequency is 240 Hz, the current ratio to the backlight is set to 100% during the backlight ON period of the normal lighting control period T, and the current ratio to the backlight is set to 0% during the backlight OFF period of the normal lighting control period T.

[0074] In frame m, blinking control is performed in the same way as in frame m-1, but because the input frequency changes to 120 Hz midway through, an additional lighting control period L in which the backlight is turned off occurs in addition to the normal lighting control period T. That is, in the additional lighting control period L, the current ratio to the backlight 22 becomes 0%.

[0075] Therefore, in blinking operation mode 1, the amount of luminance reduction during the additional lighting control period L is compensated for when the backlight is turned on in the next frame m+1. That is, by setting the current ratio to the backlight 22 to 200% during the backlight ON period of the normal lighting control period T in frame m+1, the amount of luminance reduction during the additional lighting control period L in frame m due to the change in input frequency to 120 Hz is compensated for.

[0076] Also, in frame m+1, the input frequency is 120 Hz, so similar to frame m, an additional lighting control period L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period L in frame m+1 is compensated for by setting the current ratio to the backlight 22 to 200% during the backlight ON period of the normal lighting control period T in frame m+2.

[0077] The same applies to the subsequent frames until the input frequency changes in frame n in FIG.

[0078] In frame n in Fig. 6, blinking control is performed in the same way as in frame m+1 in Fig. 5, but the input frequency changes to 80 Hz midway through, so an additional lighting control period L is generated in addition to the normal lighting control period T and the additional lighting control period L. In other words, an additional lighting control period 2L is generated.

[0079] Therefore, in blinking operation mode 1, the amount of luminance reduction during the additional lighting control period 2L is compensated for when the backlight is turned on in the next frame n+1. That is, by setting the current ratio to the backlight 22 to 300% during the backlight ON period of the normal lighting control period T in frame n+1, the amount of luminance reduction during the additional lighting control period 2L in frame n due to the change in input frequency to 80 Hz is compensated for.

[0080] Also, in frame n+1, the input frequency is 80 Hz, so similar to frame n, an additional lighting control period 2L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period 2L in frame n+1 is compensated for by setting the current ratio to the backlight 22 to 300% during the backlight ON period of the normal lighting control period T in frame n+2.

[0081] The same applies to the subsequent frames until the input frequency changes.

[0082] As described above, in blinking operation mode 1, the luminance for the additional lighting control period is compensated for as it is when the next frame is lit. Although blinking operation mode 1 increases the adverse effects of flicker, it also has a large blinking effect. Therefore, blinking operation mode 1 can be said to be a mode suitable for scenes where blinking is required or where flicker does not need to be suppressed.

[0083] FIG. 7 is a diagram showing another example of operation in the blinking operation mode 1 of FIG.

[0084] Fig. 7 differs from Fig. 5 only in that the blinking ratio is 100%. That is, since the blinking ratio is 100% in Fig. 7, blinking control is performed so that the entire normal illumination control period T is a backlight ON period.

[0085] In frame m, blinking control is performed in the same way as in frame m-1, but since the input frequency changes to 120 Hz midway, an additional lighting control period L is generated in addition to the normal lighting control period T.

[0086] 7, the amount of luminance reduction during the additional lighting control period L is also compensated for when the backlight is turned on in the next frame m+1. That is, by setting the current ratio to the backlight 22 to 200% during the normal lighting control period T in frame m+1, the amount of luminance reduction during the additional lighting control period L in frame m due to the change in input frequency to 120 Hz is compensated for.

[0087] <Blinking Operation Mode 2> FIGS. 8 and 9 are diagrams showing an example of operation in blinking operation mode 2. FIG.

[0088] Fig. 8 shows an example of operation in blinking operation mode 2 when the input frequency varies from 240 Hz to 120 Hz. Fig. 9, following Fig. 8, shows an example of operation in blinking operation mode 2 when the input frequency varies from 120 Hz to 80 Hz.

[0089] 8 and 9 show the normal lighting control period T, additional lighting control period L, and current ratio when the backlight is on when the input frequency changes from 240 Hz to 120 Hz in frame m and then from 120 Hz to 80 Hz in frame n when the blinking ratio is 50%. Therefore, in Figures 8 and 9, the normal lighting control period T is equal to or shorter than the frame period of the maximum frequency (240 Hz) of the frequency fluctuation.

[0090] Furthermore, since the blinking ratio is 50%, blinking control is performed so that half of the normal lighting control period T is a backlight ON period and half of the normal lighting control period T is a backlight OFF period.

[0091] 8, the input frequency is 240 Hz up to frame m-1, so no additional lighting control period L occurs. Furthermore, when the input frequency is 240 Hz, the current ratio to the backlight is set to 100% during the backlight ON period of the normal lighting control period T, and the current ratio to the backlight is set to 0% during the backlight OFF period of the normal lighting control period T.

[0092] In frame m, blinking control is performed in the same way as in frame m-1, but since the input frequency changes to 120 Hz midway, an additional lighting control period L is generated in addition to the normal lighting control period T.

[0093] Therefore, in the case of blinking operation mode 2, during the additional lighting control period L, the backlight 22 is not completely turned off, but is turned on so that a constant current ratio (for example, 25%) is achieved, and the remaining amount of luminance reduction during the additional lighting control period L is compensated for when the backlight is turned on in the next frame m+1.

[0094] That is, in blinking operation mode 2, the current ratio to the backlight is set to 25% during the additional lighting control period L, and the current ratio to the backlight is set to 150% during the backlight ON period of the normal lighting control period T of the next frame, thereby compensating for the amount of decrease in luminance during the additional lighting control period L in frame m due to the change in input frequency to 120 Hz.

[0095] Furthermore, in frame m+1, the input frequency is also 120 Hz, so similar to frame m, an additional lighting control period L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period L of frame m+1 is compensated for by setting the current ratio to the backlight 22 to 25% in the additional lighting control period L of frame m+1, and by setting the current ratio to the backlight 22 to 150% in the backlight ON period of the normal lighting control period T of frame m+2.

[0096] The same applies to the subsequent frames until the input frequency changes in frame n in FIG.

[0097] In frame n in Fig. 9, blinking control is performed in the same way as in frame m+1 in Fig. 8, but the input frequency changes to 80 Hz midway through, so an additional lighting control period L is generated in addition to the normal lighting control period T and the additional lighting control period L. In other words, an additional lighting control period 2L is generated.

[0098] Therefore, in blinking operation mode 2, the amount of luminance reduction during the additional lighting control period 2L is compensated for during the additional lighting control period 2L and when the backlight is turned on in the next frame n+1. That is, by setting the current ratio to the backlight 22 to 25% during the additional lighting control period 2L and setting the current ratio to the backlight 22 to 200% during the backlight ON period of the normal lighting control period T in the next frame n+1, the amount of luminance reduction during the additional lighting control period 2L in frame n due to the change in input frequency to 80 Hz is compensated for.

[0099] Furthermore, in frame n+1, the input frequency is also 80 Hz, so like frame n, an additional lighting control period 2L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period 2L of frame n+1 is compensated for by setting the current ratio to the backlight 22 to 25% without completely turning off the light in the additional lighting control period 2L of frame n+1, and by setting the current ratio to the backlight 22 to 200% during the backlight ON period of the normal lighting control period T of frame n+2.

[0100] The same applies to the subsequent frames until the input frequency changes.

[0101] As described above, in blinking operation mode 2, the luminance for the additional lighting control period is compensated for during the additional lighting control period and also during lighting in the next frame. According to blinking operation mode 2, the blinking effect is weaker than in blinking operation mode 1, but flickering is less likely to occur. In other words, when blinking operation mode 2 is used, the blinking effect is moderate and the adverse effect of flicker is also moderate.

[0102] <Blinking Operation Mode 3> FIGS. 10 and 11 are diagrams showing an example of operation in blinking operation mode 3. FIG.

[0103] Fig. 10 shows an example of operation in blinking operation mode 3 when the input frequency varies from 240 Hz to 120 Hz. Also, Fig. 11, following Fig. 10, shows an example of operation in blinking operation mode 3 when the input frequency varies from 120 Hz to 80 Hz.

[0104] 10 and 11 show the normal lighting control period T, additional lighting control period L, and current ratio when the backlight is on when the input frequency changes from 240 Hz to 120 Hz in frame m and then from 120 Hz to 80 Hz in frame n when the blinking ratio is 50%. Therefore, in Figures 10 and 11, the normal lighting control period T is equal to or shorter than the cycle of the maximum frequency (240 Hz) of the frequency fluctuation.

[0105] Furthermore, since the blinking ratio is 50%, blinking control is performed so that half of the normal lighting control period T is the backlight ON period of the normal lighting control period T, and half of the normal lighting control period T is the backlight OFF period of the normal lighting control period T.

[0106] 10 , the input frequency is 240 Hz up to frame m-1, so no additional lighting control period L occurs. Furthermore, when the input frequency is 240 Hz, the current ratio to the backlight 22 is set to 100% during the backlight ON period of the normal lighting control period T, and the current ratio to the backlight 22 is set to 0% during the backlight OFF period of the normal lighting control period T.

[0107] In frame m, blinking control is performed in the same way as in frame m-1, but since the input frequency changes to 120 Hz midway, an additional lighting control period L is generated in addition to the normal lighting control period T.

[0108] Therefore, in the case of blinking operation mode 3, the backlight is turned off during a predetermined time period L1 of the additional lighting control period L, and during the remaining time period L2, the backlight is turned on with a current ratio to the backlight 22 of 50%, and the amount of brightness reduction during the additional lighting control period L is compensated for when the backlight is turned on in the next frame m+1.

[0109] That is, in blinking operation mode 3, in the additional lighting control period L, not only a backlight OFF period L1 but also a backlight ON period L2 is provided, and the current ratio to the backlight 22 in period L2 is set to 50%, and in the backlight ON period of the normal lighting control period T of the next frame, the current ratio to the backlight 22 is set to 150%, thereby compensating for the amount of decrease in luminance in the additional lighting control period L in frame m due to the change in input frequency to 120 Hz.

[0110] Furthermore, in frame m+1, the input frequency is also 120 Hz, so like frame m, an additional lighting control period L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period L of frame m+1 is compensated for by providing not only a backlight OFF period L1 but also a backlight ON period L2 in the additional lighting control period L of frame m+1, setting the current ratio to the backlight 22 to 50% in period L2, and setting the current ratio to the backlight 22 to 150% in the backlight ON period of the normal lighting control period T of frame m+2.

[0111] The same applies to the subsequent frames until the input frequency changes in frame n in FIG.

[0112] In frame n in Fig. 11, blinking control is performed in the same way as in frame m+1 in Fig. 10, but since the input frequency changes to 80 Hz midway through, an additional lighting control period L is generated in addition to the normal lighting control period T and the additional lighting control period L. In other words, an additional lighting control period 2L is generated.

[0113] Therefore, in blinking operation mode 2, the amount of luminance reduction during the additional lighting control period 2L is compensated for during the additional lighting control period 2L and when the backlight is turned on in the next frame n+1. That is, during the additional lighting control period 2L, not only a backlight OFF period L1 but also a backlight ON period L2 is provided, and the current ratio to the backlight 22 during period L2 is set to 50%, and during the backlight ON period of the normal lighting control period T in the next frame n+1, the current ratio to the backlight is set to 150%, thereby compensating for the amount of luminance reduction during the additional lighting control period 2L in frame n due to the change in input frequency to 80 Hz.

[0114] Furthermore, in frame n+1, the input frequency is also 80 Hz, so like frame n, an additional lighting control period 2L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period 2L of frame n+1 is compensated for by providing not only a backlight OFF period L1 but also a backlight ON period L2 in the additional lighting control period 2L of frame n+1, setting the current ratio to the backlight 22 to 50% in period L2, and setting the current ratio to the backlight to 150% in the backlight ON period of the normal lighting control period T of frame n+2.

[0115] The same applies to the subsequent frames until the input frequency changes.

[0116] As described above, in blinking operation mode 3, the amount of luminance reduction corresponding to the additional lighting control period is compensated for during the additional lighting control period and also during lighting in the next frame. According to blinking operation mode 3, the blinking effect is weaker than in blinking operation mode 1, but flicker is less likely to occur. In other words, when blinking operation mode 3 is used, the blinking effect is moderate and the adverse effects of flicker are also moderate.

[0117] <Blinking Operation Mode 4> FIGS. 12 and 13 are diagrams showing an example of operation in blinking operation mode 4. In FIG.

[0118] Fig. 12 shows an example of operation in blinking operation mode 4 when the input frequency varies from 240 Hz to 120 Hz. Also, Fig. 13, following Fig. 12, shows an example of operation in blinking operation mode 4 when the input frequency varies from 120 Hz to 80 Hz.

[0119] 12 and 13 show the normal lighting control period T, additional lighting control period L, and current ratio when the backlight is on when the input frequency changes from 240 Hz to 120 Hz in frame m and then from 120 Hz to 80 Hz in frame n when the blinking ratio is 50%. Therefore, in Figures 12 and 13, the normal lighting control period T is equal to or shorter than the cycle of the maximum frequency (240 Hz) of the frequency fluctuation.

[0120] Furthermore, since the blinking ratio is 50%, blinking control is performed so that half of the normal lighting control period T is a backlight ON period and half of the normal lighting control period T is a backlight OFF period.

[0121] 12, the input frequency is 240 Hz up to frame m-1, so there is no additional lighting control period L. Furthermore, when the input frequency is 240 Hz, the current ratio to the backlight 22 is set to 100% during the backlight ON period of the normal lighting control period T, and the current ratio to the backlight 22 is set to 0% during the backlight OFF period of the normal lighting control period T.

[0122] In frame m, blinking control is performed in the same way as in frame m-1, but since the input frequency changes to 120 Hz midway, an additional lighting control period L is generated in addition to the normal lighting control period T.

[0123] Therefore, in the case of blinking operation mode 4, the backlight is not turned off but is turned on at a current ratio of 50% during the additional lighting control period L that occurs. This eliminates the need to increase the current when the backlight is turned on in the next frame m+1.

[0124] That is, in blinking operation mode 3, by lighting the backlight 22 during the additional lighting control period L, the amount of luminance reduction during the additional lighting control period L in frame m due to the change in input frequency to 120 Hz is compensated for.

[0125] Also, in frame m+1, the input frequency is 120 Hz, so similar to frame m, an additional lighting control period L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period L of frame m+1 is compensated for by lighting the backlight 22 at a current ratio of 50% in the additional lighting control period L of frame m+1.

[0126] The same applies to the subsequent frames until the input frequency changes in frame n in FIG.

[0127] In frame n in Fig. 13, blinking control is performed in the same way as in frame m+1 in Fig. 12, but since the input frequency changes to 80 Hz midway through, an additional lighting control period L is generated in addition to the normal lighting control period T and the additional lighting control period L. In other words, an additional lighting control period 2L is generated.

[0128] Therefore, in blinking operation mode 4, the amount of luminance reduction during the additional lighting control period 2L is compensated for during the additional lighting control period 2L. That is, by lighting at a current ratio of 50% during the additional lighting control period 2L, the amount of luminance reduction during the additional lighting control period 2L in frame n due to the change in input frequency to 80 Hz is compensated for.

[0129] Also, in frame n+1, the input frequency is 80 Hz, so similar to frame n, an additional lighting control period 2L occurs in addition to the normal lighting control period T. The amount of luminance reduction in the additional lighting control period 2L of frame n+1 is compensated for by lighting at a current ratio of 50% in the additional lighting control period 2L of frame n+1.

[0130] The same applies to the subsequent frames until the input frequency changes.

[0131] As described above, in blinking operation mode 4, an operation is performed to compensate for the luminance for the additional lighting control period during the additional lighting control period. According to blinking operation mode 4, the blinking effect is weaker than in blinking operation modes 2 and 3, but flicker is less likely to occur. In other words, when blinking operation mode 4 is used, the blinking effect is weaker, but the adverse effect of flicker is also less.

[0132] Furthermore, when the blinking operation mode 4 is used, a current increase for brightness compensation does not occur.

[0133] FIG. 14 is a diagram showing another example of operation in the blinking operation mode 4 of FIG.

[0134] Figure 14 differs from Figure 12 only in that during the resulting additional lighting control period L, the method of lighting the backlight 22 is changed from DC lighting to high-frequency PWM dimming, and the current ratio at that time is changed from 50% to 100%.

[0135] In this way, it is possible to reduce image blur while suppressing flicker.

[0136] 4. Operation Video Display Processing FIG. 15 is a flowchart illustrating backlight control processing by the video display processing unit 15. As shown in FIG.

[0137] The video signal from the selector 14 is supplied to a frame buffer 31, a motion vector detection unit 32, and a display control unit 34. The vertical synchronization signal from the selector 14 is supplied to a backlight control unit 33 and a display control unit 34.

[0138] In step S11 , the frame buffer 31 , the motion vector detection unit 32 , and the display control unit 34 receive the video signal supplied from the selector 14 .

[0139] In step S12 , the motion vector detection unit 32 receives the previous frame image from the frame buffer 31 .

[0140] In step S13 , the motion vector detection unit 32 detects a motion vector indicating a change in the image based on the frame image contained in the input video signal and the frame image of the immediately previous frame supplied from the frame buffer 31 .

[0141] In step S14, the motion vector detection unit 32 determines an appropriate blinking operation mode from among a plurality of blinking operation modes according to the series of motion vectors calculated on a block-by-block basis, and outputs information indicating the determined blinking operation mode to the backlight control unit 33.

[0142] In step S15 , the backlight reference signal generating unit 51 generates a backlight reference signal that serves as a reference for the backlight based on the supplied vertical synchronization signal, and outputs the generated backlight reference signal to the frequency measuring unit 52 .

[0143] In step S16, the frequency measurement unit 52 determines the length of the current frame and measures the frequency at the timing of receiving the backlight reference signal supplied from the backlight reference signal generation unit 51. The frequency measurement unit 52 outputs the frequency measurement result to the luminance reduction amount calculation unit 53.

[0144] In step S17, the brightness reduction amount calculation unit 53 uses the measurement result of the supplied frequency to calculate the brightness reduction amount due to the length of the additional lighting control period, and outputs the calculated brightness reduction amount to the backlight lighting amount calculation unit 54.

[0145] In step S18, in order to compensate for the brightness corresponding to the brightness reduction amount, the backlight illumination amount calculation unit 54 calculates the illumination amount of the backlight in the current frame and the illumination amount of the backlight in the next frame based on the information indicating the blinking operation mode supplied from the motion vector detection unit 32. The backlight illumination amount calculation unit 54 controls the backlight 22 based on the calculated illumination amount of the backlight.

[0146] For example, if the motion vector is greater than the first threshold, the motion vector detection unit 32 determines the blinking operation mode 1, which is suitable for scenes that require blinking or scenes that do not require flicker suppression. In this case, the backlight illumination amount calculation unit 54 compensates for the amount of brightness reduction by adding a current equivalent to the amount of brightness reduction when the backlight is turned on for the next frame, based on the blinking operation mode 1, as described above with reference to FIGS.

[0147] For example, when the motion vector is equal to or smaller than a first threshold and larger than a second threshold that is smaller than the first threshold, the motion vector detection unit 32 determines to select blinking operation mode 2 or blinking operation mode 3, which has a weaker blinking effect but is less likely to flicker than blinking operation mode 1.

[0148] If blinking operation mode 2 is determined, the backlight illumination amount calculation unit 54 lights up the backlight at a predetermined current ratio during the additional illumination control period based on blinking operation mode 2, as described above with reference to Figures 8 and 9, and compensates for the amount of luminance reduction by adding a current equivalent to the amount of luminance reduction when the backlight is turned on in the next frame.

[0149] Furthermore, when blinking operation mode 3 is determined, the backlight illumination amount calculation unit 54 turns on the backlight after a certain time period within the additional illumination control period based on blinking operation mode 3, as described above with reference to FIGS. 10 and 11 , and compensates for the amount of luminance reduction by adding a current equivalent to the amount of luminance reduction when the backlight is turned on in the next frame.

[0150] Furthermore, if the motion vector is equal to or less than a second threshold value that is smaller than the first threshold value, the motion vector detection unit 32 determines blinking operation mode 4, in which the blinking effect may be weakened and flicker is less likely to occur. In this case, the backlight illumination amount calculation unit 54 compensates for the amount of luminance reduction by turning on the backlight during the additional illumination control period based on blinking operation mode 4, as described above with reference to Figures 12 and 13.

[0151] During this lighting, the method of lighting the backlight 22 may be changed from DC lighting to high-frequency PWM dimming, as described above with reference to FIG.

[0152] In step S19, the motion vector detection unit 32 determines whether or not all frames have been processed. If it is determined in step S19 that all frames have not been processed, the process returns to step S11, and the subsequent processes are repeated.

[0153] If it is determined in step S19 that all frames have been completed, the backlight control process ends.

[0154] In the above description, an example was described in which the normal lighting control period T is the frame period of the maximum frequency of the video signal, but in the present technology, it is sufficient that the normal lighting control period T is equal to or shorter than the frame period of the maximum frequency of the video signal.

[0155] <5. Other> <Effects of the Present Technology> As described above, in the present technology, in blinking control, the normal lighting control period of the backlight is set to be equal to or less than the frame period at the maximum frequency of the video signal, and the amount of reduction in luminance in the additional lighting control period of the backlight caused by frequency fluctuations in the video signal is compensated for in at least one of the additional lighting control period and the normal lighting period of the next frame.

[0156] This enables blinking operation even when the input frequency fluctuates, thereby improving image blur.

[0157] Furthermore, according to the present technology, a motion vector of a video signal is detected, and the amount of luminance reduction is compensated for according to the magnitude of the motion vector.

[0158] This makes it possible to make the side effect of flicker less noticeable.

[0159] <Example of Computer Configuration> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware, or into a general-purpose personal computer, etc.

[0160] FIG. 16 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program.

[0161] The CPU 301 , ROM 302 , and RAM 303 are connected to one another via a bus 304 .

[0162] An input / output interface 305 is also connected to the bus 304. An input unit 306 including a keyboard, a mouse, etc., and an output unit 307 including a display, a speaker, etc. are connected to the input / output interface 305. In addition, a storage unit 308 including a hard disk, a nonvolatile memory, etc., a communication unit 309 including a network interface, etc., and a drive 310 that drives removable media 311 are also connected to the input / output interface 305.

[0163] In a computer configured as described above, the CPU 301 performs the above-described series of processes by, for example, loading a program stored in the storage unit 308 into the RAM 303 via the input / output interface 305 and the bus 304 and executing the program.

[0164] The program executed by the CPU 301 is provided, for example, by being recorded on a removable medium 311 or via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting, and is installed in the storage unit 308 .

[0165] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0166] In this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all of the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0167] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0168] The embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present technology.

[0169] For example, the present technology can be configured as a cloud computing system in which a single function is shared and processed collaboratively by a plurality of devices via a network.

[0170] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by a plurality of devices.

[0171] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0172] <Examples of Combinations of Configurations> The present technology may also be configured as follows. (1) A display control device including a backlight control unit that, in blinking control, sets a normal lighting control period of a backlight to be equal to or shorter than a frame period at a maximum frequency of a video signal, and compensates for a luminance reduction amount during an additional lighting control period of the backlight caused by frequency fluctuations of the video signal, during at least one of the additional lighting control period and the normal lighting period of a next frame. (2) The display control device according to (1), in which the backlight control unit compensates for the luminance reduction amount by adding a current corresponding to the luminance reduction amount when the backlight is turned on during the normal lighting control period of the next frame. (3) The display control device according to (1), in which the backlight control unit turns on the backlight at a predetermined current ratio during the additional lighting control period, and compensates for the luminance reduction amount by adding a current of the luminance reduction amount when the backlight is turned on in the next frame. (4) The display control device according to (1), wherein the backlight control unit turns on the backlight after a certain time period within the additional lighting control period, and adds a current of the amount of luminance reduction when the backlight is turned on in the next frame, thereby compensating for the amount of luminance reduction. (5) The display control device according to (1), wherein the backlight control unit compensates for the amount of luminance reduction by turning on the backlight in the additional lighting control period. (6) The display control device according to (5), wherein the backlight control unit compensates for the amount of luminance reduction by changing the backlight lighting from DC lighting to PWM dimming when lighting the backlight in the additional lighting control period. (7) The display control device according to (1), further comprising a motion vector detection unit that detects a motion vector of the video signal, wherein the backlight control unit compensates for the amount of luminance reduction in accordance with the magnitude of the motion vector. (8) The display control device according to (7), wherein the backlight control unit compensates for the amount of luminance reduction by adding a current of the amount of luminance reduction when the backlight is turned on in the next frame, when the motion vector is greater than a first threshold.(9) The display control device according to (7), wherein, when the motion vector is equal to or less than a first threshold and greater than a second threshold that is smaller than the first threshold, the backlight control unit turns on the backlight at a predetermined current ratio during the additional lighting control period and adds a current of the amount of luminance reduction when the backlight is turned on for the next frame, thereby compensating for the amount of luminance reduction. (10) The display control device according to (7), wherein, when the motion vector is equal to or less than a first threshold and greater than a second threshold that is smaller than the first threshold, the backlight control unit turns on the backlight after a certain time during the additional lighting control period and adds a current of the amount of luminance reduction when the backlight is turned on for the next frame, thereby compensating for the amount of luminance reduction. (11) The display control device according to (7), wherein, when the motion vector is equal to or less than a second threshold that is smaller than the first threshold, the backlight control unit turns on the backlight during the additional lighting control period, thereby compensating for the amount of luminance reduction. (12) The display control device according to (11), wherein the backlight control unit compensates for the amount of luminance reduction by changing the backlight lighting from DC lighting to PWM dimming during the additional lighting control period. (13) The display control device according to any of (1) to (12), wherein the backlight control unit suspends the blinking control when the frequency of the frequency fluctuation is higher than a predetermined threshold. (14) The display control device according to any of (1) to (13), wherein the backlight control unit suspends the blinking control when the frequency after the frequency fluctuation is lower than a predetermined threshold. (15) The display control device according to any of (1) to (14), further comprising a display unit including the backlight driven by the backlight control unit. (16) A display control method, in which a display control device, in blinking control, sets a normal lighting control period of a backlight to be equal to or less than a frame period at a maximum frequency of a video signal, and compensates for a decrease in luminance during an additional lighting control period of the backlight caused by a frequency fluctuation of the video signal, in at least one of the additional lighting control period and the normal lighting period of a next frame.(17) A program that causes a computer to function as a backlight control unit that, in blinking control, sets the normal lighting control period of the backlight to be equal to or less than the frame period at the maximum frequency of the video signal, and compensates for the amount of luminance reduction during the additional lighting control period of the backlight caused by frequency fluctuations of the video signal, in at least one of the additional lighting control period and the normal lighting period of the next frame.

[0173] REFERENCE SIGNS LIST 1 display device, 11 tuner, 12 HDMI receiver, 13 video distribution application, 14 selector, 15 video display processing unit, 16 display unit, 21 liquid crystal display panel, 22 backlight, 31 frame buffer, 32 motion vector detection unit, 33 backlight control unit, 34 display control unit, 51 backlight reference signal generation unit, 52 frequency measurement unit, 53 luminance reduction amount calculation unit, 54 backlight illumination amount calculation unit

Claims

1. A display control device having a backlight control unit that, in blinking control, sets the normal lighting control period of the backlight to be equal to or less than the frame period at the maximum frequency of the video signal, and compensates for the amount of luminance reduction in the additional lighting control period of the backlight caused by frequency fluctuations of the video signal, in at least one of the additional lighting control period and the normal lighting period of the next frame.

2. The display control device according to claim 1, wherein the backlight control unit compensates for the amount of luminance reduction by adding a current corresponding to the amount of luminance reduction when the backlight is turned on during the normal lighting control period of the next frame.

3. The display control device according to claim 1, wherein the backlight control unit lights the backlight at a predetermined current ratio during the additional lighting control period, and compensates for the amount of brightness reduction by adding a current of the amount of brightness reduction when the backlight is turned on in the next frame.

4. The display control device according to claim 1, wherein the backlight control unit turns on the backlight after a certain time period within the additional lighting control period, and compensates for the amount of brightness reduction by adding a current of the amount of brightness reduction when the backlight is turned on in the next frame.

5. The display control device according to claim 1, wherein the backlight control unit compensates for the amount of luminance reduction by turning on the backlight during the additional lighting control period.

6. The display control device according to claim 5, wherein the backlight control unit compensates for the amount of luminance reduction by changing the backlight lighting from DC lighting to PWM dimming during the additional lighting control period.

7. The display control device according to claim 1, further comprising a motion vector detection unit that detects a motion vector of the video signal, wherein the backlight control unit compensates for the amount of luminance reduction in accordance with a magnitude of the motion vector.

8. The display control device according to claim 7, wherein the backlight control unit compensates for the amount of luminance reduction by adding a current of the amount of luminance reduction when the backlight is turned on in the next frame if the motion vector is greater than a first threshold value.

9. The display control device according to claim 7, wherein, when the motion vector is equal to or less than a first threshold and greater than a second threshold smaller than the first threshold, the backlight control unit turns on the backlight at a predetermined current ratio during the additional lighting control period, and compensates for the amount of brightness reduction by adding a current of the amount of brightness reduction when the backlight is turned on in the next frame.

10. The display control device according to claim 7, wherein the backlight control unit, when the motion vector is equal to or less than a first threshold and greater than a second threshold smaller than the first threshold, turns on the backlight after a fixed time within the additional lighting control period, and compensates for the amount of brightness reduction by adding a current equivalent to the amount of brightness reduction when the backlight is turned on in the next frame.

11. The display control device according to claim 7, wherein the backlight control unit compensates for the amount of luminance reduction by turning on the backlight during the additional lighting control period when the motion vector is equal to or less than a second threshold value that is smaller than the first threshold value.

12. The display control device according to claim 11, wherein the backlight control unit compensates for the amount of luminance reduction by changing the backlight lighting from DC lighting to PWM dimming during the additional lighting control period.

13. The display control device according to claim 1, wherein the backlight control unit stops the blinking control when the frequency fluctuation occurs more frequently than a predetermined threshold value.

14. The display control device according to claim 1, wherein the backlight control unit stops the blinking control when the frequency after the frequency change is lower than a predetermined threshold value.

15. The display control device according to claim 1, further comprising a display unit including the backlight driven by the backlight control unit.

16. A display control method in which a display control device, in blinking control, sets a normal lighting control period of a backlight to be equal to or less than a frame period at the maximum frequency of a video signal, and compensates for a decrease in luminance in an additional lighting control period of the backlight caused by frequency fluctuations of the video signal, in at least one of the additional lighting control period and the normal lighting period of the next frame.

17. A program that causes a computer to function as a backlight control unit that, in blinking control, sets the normal lighting control period of the backlight to be equal to or less than the frame period at the maximum frequency of the video signal, and compensates for the amount of luminance reduction in the additional lighting control period of the backlight caused by frequency fluctuations of the video signal, in at least one of the additional lighting control period and the normal lighting period of the next frame.

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