JP2013061362A - Video display device, and video display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video display device with high image quality that suppresses both blur and flicker of moving images against a movement of a moving image area, since there has been a problem in which: a change width of a start phase of putting out light for preventing moving image blur increases as a moving speed of a moving image area increases; and therefore, image flicker due to a sudden change of brightness of a display screen is easily noticed.SOLUTION: A video display device suppress both blur and flicker of a moving image by sequentially moving a start phase of putting out light closer to a phase corresponding to a start position of a moving image area frame by frame in a size where flicker is not easily noticed.

Description

  The present invention relates to a technique for improving image quality in a liquid crystal display device, particularly reducing moving image blur in moving image display.

  The liquid crystal display device controls the signals for the data signal lines and the scanning signal lines to the pixels arranged in a matrix on the liquid crystal panel, writes image data once for each frame, and writes the written image to the next data. This is a display device using a hold-type display system that holds for one frame until writing.

  In such a hold-type display method, there is no problem in displaying a still image area in which an image does not change between adjacent frames, but in a moving image area in which an image changes between adjacent frames, images that differ depending on visual afterimage effects. Are superimposed on each other, and there is a problem that moving image blur occurs regardless of the response speed of the liquid crystal.

  In order to suppress such blurring of moving images, the backlight light source is turned off during the image data writing period of the moving image area and the screen display is not performed. An impulse-type display method such as a CRT display device has been proposed in which a rewritten screen is displayed at the end of writing.

  A video display device disclosed in Patent Document 1 has been proposed as one of such video display devices.

  As shown in the block diagram of FIG. 9, the conventional video display device includes a video display unit 117 that displays an input video signal, a backlight light source 116 for visualizing the video of the video display unit 117, and A moving image detection unit 112 that compares the video signal of the current frame with the video signal of the previous frame in units of pixels, detects the presence or absence of a moving image area on the scanning line, and outputs a scanning line motion determination signal for each scanning line; The PWM pulse generating means 115 for outputting a PWM pulse signal for performing the blinking control 116 and the scanning line motion determination signal from the moving image detecting means 112 turn off the light source 116 in the scanning line section for a certain period from the start of the moving image area. In this way, the PWM control means 114 for controlling the PWM pulse generation means 115 is provided.

  The PWM pulse signal generated by the PWM pulse generating means 115 turns on the light source 116 during the High period and turns off the light source 116 during the Low period, thereby controlling the luminance duty of the video display means 117.

  The PWM control unit 114 controls the PWM pulse generation unit 115 so that the light source 116 is turned off in a certain number of scanning line sections from the head scanning line of the moving image area.

  In the conventional video display device, as shown in the explanatory diagram of the light-off operation of the light source 116 in FIG. 10, the PWM output from the start pulse of the moving image area by the PWM control means 114 from the PWM pulse generation means 115 for a certain period. By turning off the light source 116 by setting the pulse signal to Low, the screen of the video display means 117 is turned off so that the data writing period in the moving image area is not displayed.

  In this way, the screen display of the video display means 117 is not performed in the writing section of the moving image area in which the image changes, and a new screen is displayed after the afterimage effect of the previous screen disappears. It becomes possible.

  As shown in FIG. 10, when the moving image area moves on the display screen, the extinction start phase is changed corresponding to the start position of the moving image area moved in the frame in which the movement has occurred (hereinafter referred to as “moving image area”). The change width of the extinction start phase is referred to as a follow-up transition width).

International Publication No. 2008/155889

  In the conventional video display device, in order to prevent motion blur due to the superimposition of old and new screens, the turn-off start phase is changed following the movement of the start position of the moving image area.

  However, as the moving speed of the moving image area increases, the follow-up transition width, which is the change width of the extinction start phase, also increases, and the ratio of the light source on / off changes rapidly, and there is a flicker due to a sudden change in the brightness of the display screen. There is a problem that it is likely to occur.

  On the other hand, if the tracking transition width is limited to reduce the occurrence of flickering, the turn-off section cannot follow the movement of the moving image area and a moving image blur occurs.

  It is an object of the present invention to provide a more preferable method for changing a light extinction start phase that does not cause moving image blur while suppressing occurrence of flickering with respect to movement of a moving image area, and a video display device using the method. And

  In order to solve the above problems, a video display device according to the present invention includes video display means for displaying an input video signal, a light source for visualizing the video on the video display means, and PWM pulse generation for controlling blinking of the light source. Means, moving picture detection means for outputting a scanning line motion determination signal for each scanning line based on a motion amount for each scanning line of the video signal, a turn-off start phase of the previous frame, and a current frame moving image obtained by the moving picture detection means Light extinction start phase calculation that calculates the extinction start phase of the current frame based on the movement direction of the area, the total number of screen scanning lines of the image display means, the luminance duty value set for the light source, and a predetermined adjustment coefficient And a PWM control means for outputting a turn-off start phase signal designating the turn-off start phase of the current frame calculated by the turn-off start phase calculating means and controlling the PWM pulse generating means. It is, it is possible to sequentially change the off start phase to the extent that Pakatsuki is inconspicuous, it is possible to provide a high-quality image display that combines motion blur suppression and Pakatsuki suppressed.

  Further, the video display device of the present invention is configured so that the moving direction of the current frame moving image area obtained by the moving image detecting means is (bottom direction of turning off the previous frame + total number of screen scanning lines × luminance duty value × adjustment). If the coefficient is in the upward direction, the extinction start phase calculation means calculates the extinction start phase of the current frame by (extinction start phase of previous frame−total number of screen scanning lines × luminance duty value × adjustment coefficient). As a result, it is possible to control the light extinction start phase suitable for the size of the screen and the set luminance duty, and it is possible to provide a high-quality video display that achieves both motion blur suppression and flicker suppression.

  Further, the video display device of the present invention is configured so that the moving direction of the current frame moving image area obtained by the moving image detecting means is (bottom direction of turning off the previous frame + total number of screen scanning lines × luminance duty value × adjustment). If the screen is in the upward direction, the provisional extinction start phase is calculated by (the extinction start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient), and the moving direction of the current frame moving image area is the bottom of the screen If the direction is the direction, if the provisional extinction start phase is smaller than the start phase of the current frame video area, the provisional extinction start phase is set as the extinction start phase of the current frame, and the provisional extinction start phase is greater than or equal to the start phase of the current frame video area Is set to the current frame moving image area start phase as the current frame moving image start phase, while if the current frame moving image region movement direction is on the screen, provisional turn-off starts. If the phase is greater than the start phase of the current frame moving image area, the provisional extinction start phase is set as the extinction start phase of the current frame, and if the temporary extinction start phase is less than or equal to the start phase of the current frame moving image area, When the extinction start phase calculation means calculates the start phase of the current frame as the start phase of the image area, in addition to the size of the screen and the set luminance duty, the moving direction of the moving image area is also taken into account Therefore, it is possible to provide a high-quality video display that achieves both motion blur suppression and flicker suppression.

  In addition, when the luminance duty value is equal to or lower than a predetermined threshold, the video display device of the present invention reduces the extinguishing start phase from the current value to 0 in steps, and the vertical blanking is performed when the extinguishing start phase becomes zero. By further providing a luminance interlocking extinction start phase instruction means for instructing the PWM control means to turn on the light source only during the period, the light source is turned off during the image display period in a low luminance state where the setting value of the luminance duty is equal to or less than the threshold value. Therefore, it is possible to provide a high-quality video display that suppresses both motion blur and flickering.

  The video display device and the video display method according to the present invention, when detecting the moving image area, sequentially bring the turn-off start phase close to the phase corresponding to the starting position of the moving image area for each frame with a non-conspicuous size. In addition, it is possible to provide a high-quality video display that suppresses both moving image blur and flickering.

It is a block diagram which shows the structure of the video display apparatus of Embodiment 1 of this invention. It is a block diagram which shows the structure of the video display apparatus of Embodiment 2 of this invention. It is explanatory drawing of the light extinguishing operation | movement of the first half at the time of the downward movement of the moving image area | region in the video display apparatus of Embodiment 1 of this invention. It is explanatory drawing of the light extinguishing operation | movement of the second half at the time of the downward movement of the moving image area | region in the video display apparatus of Embodiment 1 of this invention. It is explanatory drawing of the light extinguishing operation | movement of the first half at the time of the upward movement of the moving image area | region in the video display apparatus of Embodiment 1 of this invention. It is explanatory drawing of the light extinguishing operation | movement of the second half at the time of the upward movement of the moving image area | region in the video display apparatus of Embodiment 1 of this invention. It is explanatory drawing of the light extinction operation | movement when the light extinction start position in the video display apparatus of Embodiment 1 of this invention enters in a moving image area | region. It is explanatory drawing of the light extinguishing operation | movement when the brightness | luminance duty value in the video display apparatus of Embodiment 2 of this invention becomes below a predetermined threshold value. It is a block diagram which shows the structure of the conventional video display apparatus. It is explanatory drawing of the light extinction operation | movement in the conventional video display apparatus.

  Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a video display apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the video display device according to the first embodiment of the present invention includes a video display means 17 including a liquid crystal display panel, and a back surface that irradiates the video display means 17 such as a tube light source such as CCFL / EEFL and an LED light source. A light source 16 as a light, a PWM pulse generating means 15 for controlling the blinking of the light source 16, a PWM control means 14 for controlling the PWM pulse generating means 15, and a moving image area displayed on the video display means 17 are detected. The moving image detecting means 12 and the following transition width calculating means 13 for calculating the following transition width necessary for determining the turn-off start phase of the light source 16 are provided.

  The video display means 17 writes the input video signal once for each frame using the data signal line and the scanning signal line to the pixels arranged in a matrix of the liquid crystal display panel, and the image data Is a hold-type display device that holds for one frame until the next data write.

  The light source 16 is turned on / off based on the PWM pulse signal output from the PWM pulse generating means 15 to visualize the image data written on the liquid crystal display panel of the video display means 17.

  The light source luminance setting means 11 is a means for setting the luminance duty of the screen of the video display means 17, and the PWM control means 14 controls the PWM pulse generating means 15 based on this set value, and the light source 16 by the PWM pulse signal is used. Flashing control is performed. Further, via this light source luminance setting means 11, luminance setting according to the feature amount of the video, luminance setting according to outside light, and arbitrary luminance setting by the user are performed.

  The moving image detection means 12 detects the moving image area by comparing the video signal of the current frame and the video signal of the previous frame in units of pixels for each scanning line, and simultaneously outputs a scanning line motion determination signal for each scanning line. To do.

  The tracking transition width calculation unit 13 uses the adjustment factor set so that the screen size of the video display unit 17 and the luminance duty set by the light source luminance setting unit 11 and the flickering are not conspicuous so as to suppress the flickering as follows. Based on (Expression 1), the tracking transition width (T), which is a change width of the turn-off start phase with respect to the previous frame, is calculated and output to the PWM control means 14.

T = total number of screen scanning lines × luminance duty value × adjustment coefficient (Formula 1)
Based on the luminance duty from the light source luminance setting unit 11, the scanning line motion determination signal from the moving image detection unit 12, and the tracking transition width T from the tracking transition width calculation unit 13, the PWM control unit 14 moves the moving image area to the bottom of the screen. The turn-off start phase is calculated by each of the following (formula 2) and (formula 3) for each of the case of moving and moving upward of the screen, and the PWM pulse generating means 15 together with other control signals based on the luminance duty. Output to.

Turn-off start phase = turn-off start phase of the previous frame + T (Formula 2)
Turn-off start phase = turn-off start phase of the previous frame−T (Formula 3)
The PWM pulse generation means 15 receives the extinguishing start phase from the PWM control means 14 and other control signals, and outputs a PWM pulse signal for controlling the blinking of the light source 16.

  As the light source 16 is controlled to blink as described above, the image data writing section in the moving image area is turned off when the light source 16 is turned off, and the screen is not displayed. Thereby, moving image blur due to image superimposition of moving image areas of temporally adjacent frames is suppressed. Further, since the turn-off start phase is changed step by step, the luminance change of the display screen is limited, and the occurrence of flickering is suppressed.

  First, the change in the turn-off start phase when the moving image area moves downward on the screen will be described with reference to FIGS.

  In the first frame of FIG. 3, the light source 16 is turned on from the phase corresponding to the upper end of the screen (starting phase of the frame) to the phase corresponding to the starting position of the moving image area A moving downward in the screen. After the phase corresponding to (the turn-off start phase of the current frame), the luminance duty width (DW) set by the light source luminance setting means 11 is realized by turning off the light source 16.

  In the second frame in FIG. 3, it is necessary to move the turn-off start phase downward to the start position of the moving image region A as the moving image region A moves downward on the screen, but the moving width suppresses flickering. The tracking transition width (T) obtained by (Equation 1) is limited. Therefore, the extinguishing start phase of the second frame can be obtained by adding the tracking transition width (T) to the extinguishing start phase of the first frame based on (Equation 2). At this time, the ON period of the light source 16 (hereinafter referred to as the first actual luminance period) is a period obtained by adding the following transition width (T) to the set luminance duty width (DW) (that is, The actual luminance duty is higher than that of the first frame in FIG. 3).

  Hereinafter, until the turn-off start phase becomes a phase corresponding to the start position of the moving image area A, the first actual luminance period moves downward by the tracking transition width (T) obtained by (Equation 1) for each frame, Finally, as shown in the last frame of FIG. 4, the extinction start phase coincides with the phase corresponding to the start position of the moving image area A, and the width of the first actual luminance period is the set luminance duty width (DW )

  If the first actual luminance period is moved downward by the tracking transition width (T) obtained by (Equation 1) and the moving image area A is applied (in the case of the first frame in FIG. 4), As described in detail below, the tracking transition width (T) obtained by (Equation 1) is corrected (T ′ of the first frame in FIG. 4).

  Next, a change in the extinction start phase when the moving image area moves upward on the screen will be described with reference to FIGS.

  The first frame in FIG. 5 moves from the phase that is smaller by the luminance duty width (DW) set by the light source luminance setting means 11 than the phase corresponding to the start position of the moving image area A moving upward on the screen to the start position of the moving image area A. The state where the light source 16 is turned on to the corresponding phase and the light source 16 is turned off at other points is shown.

  In the second frame in FIG. 5, it is necessary to move the turn-off start phase upward to the start position of the moving image area A as the moving area A moves upward, but the movement width suppresses flickering. The tracking transition width (T) obtained by (Equation 1) is limited. Therefore, the extinguishing start phase of the second frame can be obtained by subtracting the tracking transition width (T) from the extinguishing start phase of the first frame based on (Equation 3). At this time, unlike the case where the moving image area moves downward on the screen, the on period of the light source 16 (hereinafter referred to as the second actual luminance period) is changed from the set luminance duty width (DW) to the tracking transition width (T ) (Ie, the actual luminance duty is lower than that of the first frame in FIG. 5).

  Hereinafter, until the turn-off start phase becomes a phase corresponding to the start position of the moving image area A, the second actual luminance period moves upward by the tracking transition width (T) obtained by (Equation 1) for each frame, Finally, as shown in the last frame of FIG. 6, the extinguishing start phase coincides with the phase corresponding to the start position of the moving image area A.

  If the second actual luminance period is moved upward by the follow-up transition width (T) obtained by (Equation 1) and is out of the moving image area A, it is obtained by (Equation 1) as described in detail later. The follow-up transition width (T) to be corrected is corrected, and the turn-off start phase is made to coincide with the phase corresponding to the start position of the moving image area A, so that the state of FIG.

  Here, in the update of the extinction start phase when the moving image area A described with reference to FIGS. 3 and 4 moves downward in the screen, the case where the extinction start phase falls within the phase interval corresponding to the moving image area A will be described with reference to FIG. Will be described.

  The PWM control unit 14 calculates the extinction start phase based on the motion determination signal indicating the moving direction of the moving image area detected by the moving image detection unit 12 and the tracking transition width (T) calculated by the tracking transition width calculation unit 13. To do.

If the video area A moves down the screen,
Temporary turn-off start phase = turn-off start phase of the previous frame + T (Formula 4)
To calculate the temporary turn-off start phase.

  Thereafter, the provisional extinction start phase is compared with the phase corresponding to the start position of the moving image area A of the current frame, and if the provisional extinction start phase is smaller than the phase corresponding to the start position of the animation area A of the current frame, the provisional extinction start phase Is the current frame extinction start phase, and if it is larger, the phase corresponding to the start position of the current frame moving image area A in order to turn off the light source 16 and suppress moving image blurring due to image superposition during drawing of the moving image region A. Is the extinguishing start phase of the current frame. When the provisional extinction start phase is larger than the phase corresponding to the start position of the moving image region A, the difference between the extinction start phase of the current frame and the extinction start phase of the previous frame is set as a corrected tracking transition width (T ′).

Similarly, in the update of the extinguishing start phase when the moving image area A described in FIGS. 5 and 6 moves in the upward direction on the screen, when the extinguishing start phase is smaller than the phase corresponding to the starting phase of the moving image area A,
Temporary extinction start phase = extinction start phase of previous frame−T (Formula 5)
To calculate the temporary turn-off start phase.

  Thereafter, the provisional extinction start phase is compared with the phase corresponding to the start position of the moving image area A of the current frame, and is set if the provisional extinction start phase is larger than the phase corresponding to the start position of the animation area A of the current frame. In order to make the flickering due to the change in brightness accompanying the change in the turn-off start phase with respect to the luminance duty inconspicuous, the provisional turn-off start phase is used as it is as the turn-off start phase of the current frame. The phase to be turned on is set as the turn-off start phase of the current frame. If the provisional extinction start phase is smaller than the phase corresponding to the start position of the moving image area A, the difference between the extinction start phase of the previous frame and the extinction start phase of the current frame is set as the corrected follow-up transition width.

  As described above, according to the first embodiment of the present invention, the light source 16 is controlled to blink on the basis of the turn-off start phase calculated in consideration of the moving direction of the moving image area, thereby moving the moving image blur in the moving image area. High-quality video display that suppresses both the image and the flickering can be realized.

(Embodiment 2)
FIG. 2 is a block diagram showing the configuration of the video display device according to the second embodiment of the present invention, as video display means 17 including a liquid crystal display panel, and a backlight such as a tube light source such as CCFL / EEFL and an LED light source. Light source 16 used, moving image detection means 12, tracking transition width calculation means output 13, PWM pulse generation means 15 for controlling blinking of light source 16, PWM control means 14 for controlling PWM pulse generation means 15, luminance The interlocking extinguishing start phase control means 18 is provided.

  Since each means other than the brightness interlocking extinction start phase control means 18 is the same as that described in the first embodiment, the description thereof is omitted below.

  FIG. 8 is a diagram for explaining a turn-off operation when the luminance duty is equal to or lower than a predetermined threshold value.

  The first frame in FIG. 8 moves downward from the phase corresponding to the upper end of the screen (starting phase of the frame) when the light source luminance setting means 11 sets the luminance duty (DW) to a low luminance equal to or lower than the threshold. The light source 16 is turned on up to the phase corresponding to the start position of the moving image area A, and the light source 16 is turned off after the phase corresponding to the start position of the moving image area A (turn-off start phase of the current frame). Shows a state where is realized.

  When the luminance duty is set to a low luminance equal to or less than the threshold value, it is necessary to turn on the light source 16 only during the vertical blanking period and to turn off the light display period during the video display period in order to suppress flickering. If the light is turned on only during the vertical blanking period, the flicker will be noticeable.

  Therefore, when the luminance-linked light extinction start phase control means 18 detects that the luminance duty is equal to or lower than the predetermined threshold value, as shown in the second frame of FIG. 8, the video display start position (vertical blanking). The turn-off start phase is moved upward by the tracking transition width (T) obtained by (Equation 1) for each frame so as to approach the phase corresponding to the period end position), and finally the last frame in FIG. As shown in FIG. 5, the light source 16 is lit only during the vertical blanking period. If the phase shifted upward by the follow-up transition width (T) obtained by (Equation 1) is smaller than the end position of the vertical blanking period (the extinguishing start phase is higher than the vertical blanking period ( In the case where there is a phase shifted upward by the tracking transition width (T) obtained by Equation 1), the tracking transition width (T) is corrected and the end position of the vertical blanking period is set as the extinguishing start phase.

  As described above, according to the second embodiment of the present invention, even when the luminance duty is equal to or lower than a predetermined threshold, high-quality video display that suppresses both moving image blur and flickering in the moving image region is realized. be able to.

  In the first and second embodiments, the period during which the light source 16 is turned off is kept constant, the period during which the light source 16 is turned on is changed by the tracking transition width (T), and the extinguishing start phase is set for each tracking transition width (T). Although the case where the light source 16 is changed has been described, conversely, the period during which the light source 16 is turned on is kept constant, the period during which the light source 16 is turned off is changed by the tracking transition width (T), and the lighting start phase is changed by the tracking transition width (T). It may be changed.

  By applying the present invention to a liquid crystal television having a display-type backlight or a projector having a light source, it is possible to provide a high-quality video display device that suppresses both motion blur and flickering.

DESCRIPTION OF SYMBOLS 11 Light source luminance setting means 12 Movie detection means 13 Tracking transition width calculation means 14 PWM control means 15 PWM pulse generation means 16 Light source 17 Video display means 18 Luminance interlocking extinction start phase control means 112 Movie detection means 114 PWM control means 115 PWM pulse generation Means 116 Light source 117 Video display means

Claims (8)

Video display means for projecting the input video signal;
A light source for visualizing the image of the image display means;
PWM pulse generating means for controlling blinking of the light source;
A moving image detecting means for outputting a scanning line motion determination signal for each scanning line based on a motion amount for each scanning line of the video signal;
The turn-off start phase of the previous frame, the moving direction of the current frame moving image area determined by the moving image detecting means, the total number of screen scanning lines of the video display means, and the luminance duty value set for the light source, An extinguishing start phase calculating means for calculating the extinguishing start phase of the current frame based on a predetermined adjustment coefficient;
A video display device comprising: a PWM control means for outputting a light extinguishing start phase signal designating the extinguishing start phase of the current frame calculated by the extinguishing start phase calculating means and controlling the PWM pulse generating means. The extinguishing start phase calculating means
If the moving direction of the current frame moving image area obtained by the moving image detecting means is the lower direction of the screen,
If the previous frame turn-off start phase + total number of screen scanning lines × luminance duty value × adjustment coefficient
2. The video display device according to claim 1, wherein the extinguishing start phase of the current frame is calculated by: extinguishing start phase of the previous frame−total number of screen scanning lines × luminance duty value × adjustment coefficient. The extinguishing start phase calculating means
If the moving direction of the current frame moving image area obtained by the moving image detecting means is the lower direction of the screen,
If the previous frame turn-off start phase + total number of screen scanning lines × luminance duty value × adjustment coefficient
The provisional extinction start phase is obtained by the extinction start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient,
If the moving direction of the current frame moving image area is the lower direction of the screen,
When the provisional extinction start phase is smaller than the start phase of the current frame moving image area, the provisional extinction start phase is set as the extinction start phase of the current frame, and the provisional extinction start phase is the start phase of the current frame moving picture area. If this is the case, the start phase of the current frame moving image area is set as the extinction start phase of the current frame,
If the moving direction of the current frame moving image area is on the screen,
When the provisional extinction start phase is larger than the start phase of the current frame moving image area, the provisional extinction start phase is set as the extinction start phase of the current frame, and the provisional extinction start phase is the start phase of the current frame moving picture area. The video display device according to claim 1, wherein in the following cases, the start phase of the current frame moving image area is set to the extinguishing start phase of the current frame. When the luminance duty value falls below a predetermined threshold value,
The extinguishing start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient is used to calculate the extinguishing start phase of the current frame, and when the extinguishing start phase of the current frame becomes 0 or less, only during the vertical blanking period The video display device according to any one of claims 1 to 3, further comprising luminance-linked turn-off start phase instruction means for instructing the PWM control means to turn on a light source. A video display step of projecting the input video signal on a video display means;
A PWM pulse generating step for generating a PWM pulse for controlling blinking of a light source for visualizing an image of the image display means;
A moving image detection step for outputting a scanning line motion determination signal for each scanning line based on a motion amount for each scanning line of the video signal;
The turn-off start phase of the previous frame, the moving direction of the current frame moving image area obtained in the moving image detecting step, the total number of screen scanning lines of the video display means, and the luminance duty value set for the light source, A turn-off start phase calculating step for calculating a turn-off start phase of the current frame based on a predetermined adjustment coefficient;
An image display method comprising: a PWM control step for outputting a light extinguishing start phase signal for designating the extinguishing start phase of the current frame calculated in the extinguishing start phase calculating step, and controlling the generation of the PWM pulse. The extinguishing start phase calculating step includes
If the moving direction of the current frame moving image area obtained by the moving image detecting step is the lower direction of the screen,
If the previous frame turn-off start phase + total number of screen scanning lines × luminance duty value × adjustment coefficient
6. The video display method according to claim 5, wherein the extinguishing start phase of the current frame is calculated by the extinguishing start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient. The extinguishing start phase calculating step includes
If the moving direction of the current frame moving image area obtained by the moving image detecting step is the lower direction of the screen,
If the previous frame turn-off start phase + total number of screen scanning lines × luminance duty value × adjustment coefficient
The provisional extinction start phase is obtained by the extinction start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient,
If the moving direction of the current frame moving image area is the lower direction of the screen,
When the provisional extinction start phase is smaller than the start phase of the current frame moving image area, the provisional extinction start phase is set as the extinction start phase of the current frame, and the provisional extinction start phase is the start phase of the current frame moving picture area. If this is the case, the start phase of the current frame moving image area is set as the extinction start phase of the current frame,
If the moving direction of the current frame moving image area is on the screen,
When the provisional extinction start phase is larger than the start phase of the current frame moving image area, the provisional extinction start phase is set as the extinction start phase of the current frame, and the provisional extinction start phase is the start phase of the current frame moving picture area. 6. The video display method according to claim 5, wherein a start phase of the current frame moving image area is set as a turn-off start phase of the current frame when the following is true. When the luminance duty value falls below a predetermined threshold value,
The PWM control step includes
The extinguishing start phase of the previous frame−the total number of screen scanning lines × the luminance duty value × the adjustment coefficient is used to calculate the extinguishing start phase of the current frame, and when the extinguishing start phase of the current frame becomes 0 or less, only during the vertical blanking period The video display method according to claim 5, wherein the generation of the PWM pulse is controlled so that the light source is turned on.

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