WO2020235177A1 - Image display device and control method for image display device - Google Patents

Image display device and control method for image display device Download PDF

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Publication number
WO2020235177A1
WO2020235177A1 PCT/JP2020/009544 JP2020009544W WO2020235177A1 WO 2020235177 A1 WO2020235177 A1 WO 2020235177A1 JP 2020009544 W JP2020009544 W JP 2020009544W WO 2020235177 A1 WO2020235177 A1 WO 2020235177A1
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Prior art keywords
brightness
pixel
video signal
pixels
light sources
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PCT/JP2020/009544
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French (fr)
Japanese (ja)
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高橋　昌之
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シャープ株式会社
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Publication of WO2020235177A1 publication Critical patent/WO2020235177A1/en

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals

Definitions

  • the present disclosure relates to an image display device and a control method for the image display device.
  • the present application claims priority to Japanese Patent Application No. 2019-099366 filed in Japan on May 17, 2019, the contents of which are incorporated herein by reference.
  • a technology called local dimming technology is known in an image display device that displays an image by irradiating a display panel with illumination light from a backlight.
  • the local dimming technology is a technology that divides the backlight into a plurality of light emitting regions and controls the plurality of light emitting regions independently to increase the contrast in one screen and at the same time suppress the power consumption.
  • Patent Document 1 discloses an example of an image display device using such a local dimming technique.
  • a conversion characteristic is set in which the brightness value of the processing target pixel is lowered as the brightness around the processing target pixel is higher, and gradation conversion is performed using the set conversion characteristic. ing. This makes it possible to compensate for image quality deterioration due to uneven brightness of the displayed image or partial decrease in contrast.
  • the image display device as described above may not be able to display an image faithful to the input video signal depending on the number of light emitting areas among the plurality of light emitting areas.
  • One aspect of the present disclosure is to realize an image display device capable of displaying an image having high fidelity to an input video signal regardless of the lighting state of a plurality of light sources (light emitting regions) that can be independently lit. ..
  • the image display device has a display area in which a plurality of pixels are arranged, a display panel for displaying an image based on an input video signal, and the display area.
  • a plurality of independently lit light sources that illuminate the plurality of pixels in the above
  • a luminance distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources that illuminate each of the plurality of pixels, and attention.
  • the maximum brightness of the illumination light applied to the pixel of interest is set to 1, and the relative value with respect to the brightness calculated by the brightness distribution calculation unit.
  • the image display device has a display area in which a plurality of pixels are arranged, and independently illuminates a display panel that displays an image based on a video signal and the plurality of pixels in the display area.
  • a brightness distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources that is irradiated to each of the plurality of pixels, and a pixel of interest among the plurality of light sources.
  • the maximum brightness of the illumination light applied to the pixel of interest is set as the maximum brightness, and there are pixels whose brightness calculated by the brightness distribution calculation unit is larger than the maximum brightness.
  • a light source data correction unit that reduces the output of some of the light sources is provided so that the brightness calculated by the brightness distribution calculation unit is equal to or less than the maximum brightness.
  • the control method of the image display device has a display area in which a plurality of pixels are arranged, and illuminates a display panel for displaying an image based on a video signal and the plurality of pixels in the display area.
  • a method of controlling an image display device including a plurality of light sources that can be turned on independently, and calculating a brightness distribution for calculating the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels.
  • the brightness calculated in the brightness distribution calculation step where the maximum brightness of the illumination light applied to the attention pixel is set to 1 when only one of the plurality of light sources corresponding to the process and the attention pixel is lit. It includes a correction coefficient calculation step of calculating a relative value of the above, and a video signal correction step of dividing the gradation value of the pixel of interest based on the input video signal by the relative value.
  • the control method of the image display device has a display area in which a plurality of pixels are arranged, illuminates a display panel for displaying an image based on a video signal, and the plurality of pixels in the display area.
  • the maximum brightness of the illumination light applied to the pixel of interest is set as the maximum brightness, and the brightness distribution is calculated.
  • a light source that reduces the output of some of the light sources so that the brightness calculated in the brightness distribution calculation step is equal to or less than the maximum brightness when there is a pixel whose brightness calculated in the step is greater than the maximum brightness. It includes a data correction step.
  • an image having high fidelity to an input video signal can be displayed regardless of the lighting state of a plurality of light sources that can be turned on independently.
  • FIG. (C) is a graph showing the liquid crystal transmittance after correction by the video signal correction unit
  • (d) is a graph showing the display brightness in the display unit 3. It is a figure which shows the state which displayed the solid image of 100% white on the whole surface on the display part.
  • A is a diagram showing the brightness of the window when a small window is displayed on the conventional display device
  • (b) is a diagram showing the brightness of the window when the small window is displayed on the display device. is there.
  • It is a block diagram which shows the structure of the display device which concerns on Embodiment 2.
  • It is a flowchart which shows an example of the processing flow in a display device.
  • It is a block diagram which shows the structure of the display device which concerns on Embodiment 3.
  • FIG. 1 is a block diagram showing a configuration of a display device 1 according to the present embodiment.
  • the display device 1 is an image display device that displays an input image which is an image indicated by an input video signal, and includes a main control unit 2, a display unit 3, and a storage unit 4.
  • the display device 1 may be a portable information terminal or a stationary display device.
  • the main control unit 2 is a device that comprehensively controls the display device 1, and particularly functions as an image processing device.
  • the storage unit 4 stores a program or the like processed by the main control unit 2.
  • the display unit 3 displays the input image processed by the main control unit 2.
  • the display unit 3 is a liquid crystal display.
  • the display unit 3 includes a display panel 31, a display panel drive unit 32, an LED backlight 33 (hereinafter referred to as BL33), and an LED drive unit 34 (hereinafter referred to as BL drive unit 34).
  • the display panel 31 has a display area in which a plurality of pixels 35 are arranged and displays an image based on an input video signal (input video signal), and is a liquid crystal display panel in the present embodiment.
  • the input video signal may be a signal indicating a moving image or a signal indicating a still image.
  • the display panel drive unit 32 drives the display panel 31 with the output value indicated by the liquid crystal data generated by the video signal correction unit 25, which will be described later.
  • the BL drive unit 34 controls the lighting of the BL 33 according to the backlight data (hereinafter, BL data) received from the BL control unit 27. By these drive controls, the input image is displayed on the display panel 31.
  • FIG. 2 is a diagram for explaining an example of display processing using the local dimming function in the display device 1.
  • a region having a high gradation value is shown in a color close to white.
  • the BL 33 includes a plurality of light emitting areas (LEDs) 36 as independently lit light sources that illuminate the plurality of pixels 35 in the display area of the display panel 31.
  • the display device 1 has a local dimming function that controls lighting for each light emitting region 36.
  • the light emitting regions 36 are arranged in a matrix, and in the example shown in FIG. 2, the BL 33 is divided into m ⁇ n light emitting regions 36.
  • Each light emitting area 36 may be realized by one LED, or two or more LEDs may be provided in each light emitting area 36.
  • the light source included in the BL33 is not limited to the LED, and may be another type of light emitting element.
  • the main control unit 2 includes a gamma conversion unit 21, a BL data calculation unit (light source data calculation unit) 22, a brightness distribution calculation unit 23, a correction coefficient calculation unit 24, a video signal correction unit 25, and an inverse gamma. It includes a conversion unit 26 and a BL control unit 27.
  • the gamma conversion unit 21 gamma-converts the input video signal according to the format of the input video signal by referring to a look-up table or the like to obtain a linear signal.
  • the BL data calculation unit 22 calculates the outputs (LED lighting rates) of the plurality of light emitting regions 36 based on the gamma-converted video signal, and the backlight data (BL data) indicating the outputs (see FIG. 2). To generate. Specifically, the input image is divided into an area corresponding to the light emitting area 36 (referred to as a divided display area), and corresponds to the maximum gradation value among the gradation values of the pixels 35 included in each divided display area. As described above, the output of the light emitting region 36 is determined.
  • the gradation value of a pixel 35 when it expresses as "the gradation value of a pixel 35", it means the gradation value corresponding to the pixel 35 of interest among a plurality of gradation values included in an input video signal. To do. It is assumed that the plurality of gradation values and the plurality of pixels 35 included in the input video signal have a one-to-one correspondence.
  • the BL control unit 27 controls the drive of the BL 33 by outputting the BL data generated by the BL data calculation unit 22 to the BL drive unit 34.
  • the brightness distribution calculation unit 23 calculates the brightness of the illumination light (backlight light) from the plurality of light emitting regions 36 that is irradiated to each of the plurality of pixels 35. Specifically, the luminance distribution calculation unit 23 calculates the luminance distribution of BL33 based on the luminance data and the luminance diffusion function (PSF, Point Spread Function) which is data expressing how the light is diffused numerically. To do.
  • PSF Point Spread Function
  • the correction coefficient calculation unit 24 illuminates the attention pixel when only one light emitting region 36 corresponding to one pixel 35 (attention pixel) of the plurality of pixels 35 included in the display panel 31 is lit.
  • a relative value (hereinafter, referred to as a correction coefficient) for the brightness of the illumination light calculated by the brightness distribution calculation unit 23 is calculated for the pixel of interest, with the maximum brightness of 1 being 1.
  • the correction coefficient calculation unit 24 performs this process on all the pixels 35 included in the display panel 31.
  • the inverse gamma conversion unit 26 converts the linear video signal generated by the gamma conversion unit 21 into an inverse gamma according to the display gamma of the display panel 31.
  • the video signal correction unit 25 corrects the gradation value of each pixel 35 indicated by the gamma-converted video signal by using the correction coefficient corresponding to the pixel 35. That is, the video signal correction unit 25 divides the gradation value of the pixel of interest based on the input video signal by the correction coefficient. For example, the video signal correction unit 25 divides the gradation value of each pixel 35 by the correction coefficient corresponding to the pixel 35. Therefore, when the correction coefficient is larger than 1, the gradation value of the pixel of interest to be corrected becomes small, and when the correction coefficient is smaller than 1, the gradation value of the pixel of interest becomes large. The video signal correction unit 25 may multiply the gradation value of each pixel 35 by the reciprocal of the correction coefficient.
  • the video signal correction unit 25 generates a final video signal by referring to the information of the video signal converted to the reverse gamma by the reverse gamma conversion unit 26, and outputs the final video signal as liquid crystal data to the display panel drive unit 32.
  • the liquid crystal data is data indicating the liquid crystal transmittance.
  • FIG. 3 is a diagram showing a luminance distribution when a plurality of light emitting regions 36 emit light. The significance of the processing in the correction coefficient calculation unit 24 and the video signal correction unit 25 will be described.
  • the peaks 51 and 52 are generated by the illumination light from the two light emitting regions 36, respectively.
  • the brightness of the illumination light in the pixel 35 (the pixel of interest) that receives the illumination light from these two light emitting regions 36 can be expressed as a peak 53. That is, the brightness of the illumination light in the pixel 35 increases by the amount indicated by the reference numeral 54.
  • the region indicated by reference numeral 55 corresponds to one light emitting region 36.
  • the correction coefficient calculation unit 24 is based on the input video signal so that even when the pixel of interest is illuminated with the maximum brightness of the peak 53, the same display brightness as when illuminated with the maximum brightness of one light emitting region 36 is realized.
  • a correction coefficient for correcting the gradation value of each pixel 35 is calculated. For example, if the increase indicated by reference numeral 54 is 1.2, the correction coefficient calculation unit 24 calculates 1.2 as the correction coefficient. In this case, the video signal correction unit 25 divides the gradation value of the pixel of interest indicated by the gamma-converted video signal by 1.2.
  • FIG. 4 is a flowchart showing an example of the processing flow in the display device 1.
  • the gamma conversion unit 21 receives the input video signal from an external device, it gamma-converts the input video signal by referring to a look-up table or the like corresponding to the format of the input video signal. Then, it becomes a linear signal (S1).
  • the inverse gamma conversion unit 26 performs inverse gamma conversion in accordance with the display gamma of the display panel 31 from the linear video signal generated by the gamma conversion unit 21 (S2).
  • the BL data calculation unit 22 calculates the outputs (LED lighting rates) of the plurality of light emitting regions 36 based on the video signal gamma-converted by the gamma conversion unit 21, and generates BL data indicating the outputs. (S3).
  • the BL data calculation unit 22 outputs the generated BL data to the luminance distribution calculation unit 23 and the BL control unit 27.
  • the brightness distribution calculation unit 23 calculates the brightness of the illumination light (brightness distribution of BL 33) from the plurality of light emitting regions 36 to be irradiated to each of the plurality of pixels 35 based on the BL data and the PSF (S4). (Brightness distribution calculation process).
  • the luminance distribution calculation unit 23 outputs data indicating the luminance distribution to the correction coefficient calculation unit 24.
  • the correction coefficient calculation unit 24 calculates a correction coefficient, which is a relative value for the brightness of the illumination light calculated by the brightness distribution calculation unit 23, for the pixel of interest (correction coefficient calculation step).
  • the correction coefficient calculation unit 24 performs this process on all the pixels 35 included in the display panel 31 (S5).
  • the correction coefficient calculation unit 24 outputs the calculated correction coefficient of each pixel 35 to the video signal correction unit 25.
  • the video signal correction unit 25 When the video signal correction unit 25 receives the correction coefficient from the correction coefficient calculation unit 24, the video signal correction unit 25 corrects the gradation value of each pixel 35 indicated by the gamma-converted video signal by using the correction coefficient corresponding to the pixel 35 ( S6) (Video signal correction step).
  • the video signal correction unit 25 generates a final video signal by referring to the information of the video signal converted to the reverse gamma by the reverse gamma conversion unit 26, and displays the display panel drive unit 32 as liquid crystal data indicating the liquid crystal transmittance. Output to.
  • the display panel drive unit 32 drives the display panel 31 with the output value indicated by the liquid crystal data generated by the video signal correction unit 25 (S7).
  • the BL control unit 27 controls the drive of the BL 33 by outputting the BL data generated by the BL data calculation unit 22 to the BL drive unit 34 (S8). By these drive controls, the input image is displayed on the display panel 31.
  • FIG. 5A and 5B are diagrams for explaining the effect of the display device 1
  • FIG. 5A is a graph showing the gradation value of the input video signal
  • FIG. 5B is a graph showing the gradation value of the input video signal according to the gradation value of the input video signal. It is a graph which shows the luminance distribution of the light emitting region 36 which emitted light
  • (c) is a graph which shows the liquid crystal transmittance after correction by a video signal correction part 25
  • (d) is a graph which shows display brightness in display part 3. is there.
  • each of the five horizontally arranged light emitting regions 36 is a gradation value (transmittance conversion) of the input video signal shown in FIG. 5A (FIG. 5). It is assumed that light is emitted according to the broken line 56) in (b) of 5. In this case, the actual luminance distribution is as shown by the solid line 57 in FIG. 5B. This is because the light emitting area 36 emits light so as to realize the maximum gradation value among the plurality of pixels 35 included in the corresponding divided display area.
  • the correction coefficient calculation unit 24 calculates the relative value of the brightness of the illumination light for each pixel 35 when the maximum brightness of the illumination light applied to the pixel of interest is 1 when the light emitting region 36 is lit by itself. To do.
  • the video signal correction unit 25 divides the gradation value of each pixel 35 included in the video signal by the relative value (correction coefficient).
  • the liquid crystal transmittance becomes as shown in the graph shown in FIG. 5 (c). Since the actual display luminance in the display unit 3 is the product of the solid line 57 shown in FIG. 5 (b) and the liquid crystal transmittance, the input gradation indicated by the input video signal is shown in FIG. 5 (d). The same display brightness as the value can be realized.
  • the gradation value of the pixel 35 can be appropriately corrected. As a result, an image having high fidelity to the input video signal can be displayed regardless of the number of lit light emitting regions 36 among the plurality of light emitting regions 36.
  • FIG. 6 is a diagram showing a state in which a solid image of 100% white on the entire surface is displayed on the display unit 3.
  • FIG. 7 shows the input video signal between A and B in FIG. 6 converted into transmittance (displayed as “input”), the luminance distribution of BL33 (displayed as “BL luminance distribution”), and the corrected liquid crystal transmittance. It is a figure which showed the actual display luminance in order in the display part 3. For convenience, it is assumed that the number of light emitting regions 36 between A and B is 5, and one light emitting region 36 includes 20 pixels 35.
  • FIG. 8 is a diagram showing a state in which a 100% white window on a 0% black background is displayed at a position slightly smaller than the size of the light emitting area 36 and shifted to the right side of the drawing from the center of the light emitting area 36.
  • FIG. 9 is a diagram showing the luminance distribution of BL33 in the state of FIG. In BL33, the light emitting area 36 corresponding to the white window and the light emitting area 36 around the light emitting area 36 are lit.
  • FIG. 10 shows a value obtained by converting the input signal between A and B in FIG. 8 into transmittance (displayed as “input”), the luminance distribution of BL33 (displayed as “BL luminance distribution”), and after correction by the video signal correction unit 25.
  • the liquid crystal transmittance of the above and the actual display brightness in the display unit 3 are shown in order. As in the case of FIG. 6, it is assumed that five light emitting regions 36 are included between A and B, and that one light emitting region 36 includes 20 pixels 35.
  • the image indicated by the input video signal has a window slightly to the right of the center of the central light emitting area 36 (referred to as the central area).
  • the central area is 100%
  • the light emitting area 36 on the right side of the central area is 80%
  • the light emitting area 36 on the left side of the central area is 50%
  • the other light emitting areas 36 are 0%. Since the brightness of the pixel 35 corresponding to the central area becomes larger than 1 when shining in this way, the desired brightness can be realized by lowering the gradation of the pixel 35 whose brightness becomes larger than 1.
  • FIG. 11A is a diagram showing the brightness of the window when the small window 61 is displayed on the conventional display device 300
  • FIG. 11B is a diagram showing the small window 62 on the display device 1. It is a figure which shows the brightness of the said window at the time.
  • the liquid crystal data is corrected with the maximum brightness when a completely white image is input, that is, when the LED emits light at the maximum emission intensity over the entire emission region. Is done.
  • the light emitting area is reduced, so that the backlight becomes dark and the displayed brightness becomes small. Therefore, the window 61 is displayed in gray.
  • the image can be displayed with the same brightness regardless of whether the white image is displayed on the entire surface or a small window is displayed. That is, in the example shown in FIG. 11B, the window 62 is displayed in white.
  • the brightness does not change regardless of the size of the window, but the backlight always emits light on the entire surface, so that the power consumption is large.
  • the power consumption it is necessary to lower the brightness, but in the display device 1, the power consumption can be suppressed and the contrast can be increased by local dimming.
  • FIG. 12 is a block diagram showing the configuration of the display device 1A according to the present embodiment. As shown in FIG. 12, the display device 1A of the present embodiment includes a BL power correction unit (power correction unit) 28 in addition to the configuration of the display device 1.
  • BL power correction unit power correction unit
  • the BL power correction unit 28 receives the BL data and calculates the total power consumption of the BL 33 from the outputs of the plurality of light emitting regions 36 calculated by the BL data calculation unit 22. Further, when the calculated power consumption exceeds a predetermined value, the BL power correction unit 28 reduces the output of at least a part of the light emitting region 36 in the BL data so that the power consumption does not exceed the predetermined value. ..
  • the BL power correction unit 28 reduces the output value of each light emitting region 36 in the BL data at a uniform rate or as the output value increases so that the power consumption of the BL 33 becomes equal to or less than the predetermined value. To lower it.
  • the mode for reducing the output value of the light emitting region 36 is not particularly limited.
  • the predetermined value of power consumption is, for example, the illumination from the light emitting region 36 when the brightness of each pixel 35 is the maximum brightness, that is, when only one of the light emitting regions 36 is lit in a state where the BL 33 is entirely lit.
  • the power consumption does not exceed the maximum value of the brightness of the illumination light in the pixel 35 that receives the light.
  • the predetermined value may be appropriately set according to the specifications of the display device 1A, and is not particularly limited.
  • the luminance distribution calculation unit 23 illuminates each of the plurality of pixels 35 based on the BL data output from the BL data calculation unit 22 from the plurality of light emitting regions 36.
  • the brightness of the light may be calculated.
  • the brightness distribution calculation unit 23 may receive the corrected BL data output from the BL power correction unit 28 and calculate the brightness of the illumination light.
  • FIG. 13 is a flowchart showing an example of the processing flow in the display device 1A.
  • each step of S11 to S17 is the same as each step of S1 to S7 shown in FIG.
  • the BL data calculation unit 22 generates BL data based on the video signal gamma-converted by the gamma conversion unit 21 (S13).
  • the BL data calculation unit 22 outputs the generated BL data to the luminance distribution calculation unit 23 and the BL power correction unit 28.
  • the BL power correction unit 28 calculates the total power consumption of the BL 33 from the outputs of the plurality of light emitting regions 36 indicated by the BL data (S18).
  • the BL power correction unit 28 covers at least a part of the light emitting region 36 in the BL data so that the power consumption does not exceed the predetermined value.
  • the output is reduced (S20). Further, the BL power correction unit 28 outputs the corrected BL data to the BL control unit 27.
  • the BL power correction unit 28 outputs the BL data to the BL control unit 27 without correcting it.
  • the BL control unit 27 controls the drive of the BL 33 by outputting the BL data received from the BL power correction unit 28 to the BL drive unit 34 (S21).
  • the BL power correction unit 28 consumes the power.
  • BL data is corrected so that is equal to or less than a predetermined value.
  • FIG. 8 in the state where only a small window is displayed, the power consumption of the BL 33 does not exceed a predetermined value, so that the BL power correction unit 28 does not correct the BL data. Therefore, it is possible to display an image having high fidelity to the input video signal while suppressing the power consumption within a predetermined range.
  • FIG. 14 is a block diagram showing the configuration of the display device 1B according to the present embodiment.
  • the display device 1B of the present embodiment includes a BL data correction unit (light source data correction unit) 29 in addition to the configuration of the display device 1.
  • BL data correction unit light source data correction unit
  • the correction coefficient calculation unit 24 Since the correction coefficient calculation unit 24 is not an indispensable component in the display device 1B, the correction coefficient calculation unit 24 may be omitted. In this case, the video signal correction unit 25 does not correct the gradation value using the correction coefficient, and similarly to the conventional case, the video signal correction unit 25 calculates the gradation value of the video signal based on the luminance distribution calculated by the luminance distribution calculation unit 23. It should be corrected.
  • the maximum amount of illumination light emitted to the pixel of interest is the maximum.
  • the brightness is called the maximum brightness.
  • the light emitting area 36 (central light emitting area) corresponding to the pixel of interest and the light emitting area 36 around the light emitting area 36 are lit. It means to light up.
  • the light emitting region 36 preset as the peripheral light emitting region may be a light emitting region 36 located around the central light emitting region (up / down, left / right, diagonal direction), and the light emitting region 36 surrounding the outer side thereof may be peripherally emitted. It may be included in the area.
  • the peripheral light emitting region may be set in consideration of, for example, the size or distribution shape of the light emitting points of the light emitting region 36 based on PSF.
  • the central light emitting region and the peripheral light emitting region are, for example, 5 ⁇ 5 light emitting regions 36.
  • the brightness distribution calculation unit 23 calculates the brightness of the illumination light from the plurality of light emitting regions 36 to be irradiated to each of the plurality of pixels 35.
  • the BL data correction unit 29 makes the brightness of the illumination light equal to or less than the maximum brightness when there is a pixel 35 (attention pixel) whose brightness of the illumination light calculated by the brightness distribution calculation unit 23 is larger than the maximum brightness.
  • the output of the partial light emitting region 36 that is, the central light emitting region and the peripheral light emitting region
  • the BL data correction unit 29 makes the brightness of the illumination light equal to or less than the maximum brightness when there is a pixel 35 whose brightness of the illumination light calculated by the brightness distribution calculation unit 23 is larger than the maximum brightness.
  • BL data is corrected for the part of the light emitting region 36.
  • the BL data correction unit 29 calculates the relative value of the brightness of the illumination light of the pixel of interest when the maximum brightness is 1, and divides the output value of the part of the light emitting region 36 by the relative value. To do.
  • the method for correcting BL data in the BL data correction unit 29 is not limited to this method, and any method may be used as long as the brightness of the illumination light of the pixel of interest is equal to or less than the maximum brightness.
  • FIG. 15 is a flowchart showing an example of the processing flow in the display device 1B.
  • each step of S31 to S33 is the same as each step of S1 to S3 shown in FIG.
  • the luminance distribution calculation unit 23 calculates the luminance distribution of BL33 based on the BL data and the PSF, as in the process in step S4 (S34).
  • the brightness distribution calculation unit 23 outputs data indicating the brightness distribution to the BL data correction unit 29.
  • the BL data correction unit 29 determines whether or not the brightness of the illumination light of each pixel 35 is the maximum brightness "1" or less. When the brightness of the attention pixel is not “1" or less (NO in S35), the BL data correction unit 29 performs the center corresponding to the attention pixel so that the brightness of the illumination light becomes the maximum brightness "1" or less. BL data is corrected in order to reduce the output of the light emitting region and the peripheral light emitting region (S36) (light source data correction step). The BL data correction unit 29 outputs the corrected BL data to the luminance distribution calculation unit 23, and performs the processes of steps S34 and S35 again.
  • the BL data correction unit 29 performs the correction coefficient calculation unit 24 and the BL control without correcting the BL data. Output to unit 27.
  • step S40 the BL control unit 27 acquires BL data from the BL data correction unit 29.
  • the BL data correction unit 29 makes the illumination light brightness of the pixel 35 equal to or less than the maximum brightness. As described above, the output of the central light emitting region corresponding to the pixel 35 and the light emitting region around the central light emitting region is reduced.
  • the power consumption of the display device 1B can be made lower than that of the display device 1.
  • Control blocks of display devices 1, 1A, 1B (particularly, BL data calculation unit 22, brightness distribution calculation unit 23, correction coefficient calculation unit 24, video signal correction unit 25, BL control unit 27, BL power correction unit 28, and BL data.
  • the correction unit 29 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.
  • the display devices 1, 1A, and 1B include a computer that executes a program instruction, which is software that realizes each function.
  • the computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present disclosure.
  • the processor for example, a CPU (Central Processing Unit) can be used.
  • the recording medium in addition to a “non-temporary tangible medium” such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used.
  • a RAM RandomAccessMemory
  • the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program.
  • a transmission medium communication network, broadcast wave, etc.
  • one aspect of the present disclosure can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.
  • the main control unit 2 which is the control device of the display devices 1, 1A, and 1B according to each aspect of the present disclosure may be realized by a computer.
  • each unit in this case, including the computer.
  • a control program of a display device that realizes the main control unit 2 on a computer by operating as a software element) and a computer-readable recording medium that records the control program are also included in the scope of the present disclosure.

Abstract

This image display device comprises: a display panel that has a display area in which a plurality of pixels are arranged and displays an image based on an input video signal; a plurality of light sources that illuminate the plurality of pixels in the display area and can be independently turned on; a brightness distribution calculation unit that calculates the brightness of illumination light which is emitted from the plurality of light sources and with which each of the plurality of pixels is irradiated; a correction coefficient calculation unit that calculates a relative value for the brightness calculated by the brightness distribution calculation unit under the assumption that the maximum brightness of the illumination light with which a pixel of interest is irradiated when only one of the plurality of light sources corresponding to the pixel of interest is turned on is set as 1; and a video signal correction unit that divides a gradation value of the pixel of interest based on the input video signal by the relative value.

Description

画像表示装置および画像表示装置の制御方法Image display device and control method of image display device
　本開示は、画像表示装置および画像表示装置の制御方法に関する。本願は、２０１９年５月１７日に、日本に出願された特願２０１９－０９３９６６に優先権を主張し、その内容をここに援用する。 The present disclosure relates to an image display device and a control method for the image display device. The present application claims priority to Japanese Patent Application No. 2019-099366 filed in Japan on May 17, 2019, the contents of which are incorporated herein by reference.
　バックライトからの照明光を表示パネルに照射することにより画像を表示する画像表示装置において、ローカルディミング技術と呼ばれる技術が知られている。ローカルディミング技術とは、バックライトを複数の発光領域に分割し、複数の発光領域を独立して制御することにより、一画面内のコントラストを高めると同時に、消費電力を抑える技術である。 A technology called local dimming technology is known in an image display device that displays an image by irradiating a display panel with illumination light from a backlight. The local dimming technology is a technology that divides the backlight into a plurality of light emitting regions and controls the plurality of light emitting regions independently to increase the contrast in one screen and at the same time suppress the power consumption.
　このようなローカルディミング技術を用いた画像表示装置の一例が特許文献１に開示されている。特許文献１に記載の画像表示装置では、処理対象画素の周囲の明度が高いほど当該処理対象画素の輝度値を低くする変換特性を設定し、設定された変換特性を用いて階調変換を行っている。これにより、表示画像の輝度ムラあるいは部分的なコントラスト低下による画質劣化を補償することができる。 Patent Document 1 discloses an example of an image display device using such a local dimming technique. In the image display device described in Patent Document 1, a conversion characteristic is set in which the brightness value of the processing target pixel is lowered as the brightness around the processing target pixel is higher, and gradation conversion is performed using the set conversion characteristic. ing. This makes it possible to compensate for image quality deterioration due to uneven brightness of the displayed image or partial decrease in contrast.
国際公開第２０１１／０４００２１号International Publication No. 2011/040021
　しかしながら、上述のような画像表示装置では、複数の発光領域のうちの、発光する発光領域の数によっては、入力映像信号に忠実な画像を表示できない場合がある。 However, the image display device as described above may not be able to display an image faithful to the input video signal depending on the number of light emitting areas among the plurality of light emitting areas.
　本開示の一態様は、独立して点灯可能な複数の光源（発光領域）の点灯状態によらず、入力映像信号に対する忠実性の高い画像を表示できる画像表示装置を実現することを目的とする。 One aspect of the present disclosure is to realize an image display device capable of displaying an image having high fidelity to an input video signal regardless of the lighting state of a plurality of light sources (light emitting regions) that can be independently lit. ..
　上記の課題を解決するために、本開示の一態様に係る画像表示装置は、複数の画素が配列された表示領域を有し、入力映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源と、前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出部と、注目画素に対応する、前記複数の光源の内の１つのみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を１とし、前記輝度分布算出部が算出した輝度についての相対値を算出する補正係数算出部と、前記入力映像信号に基づく前記注目画素の階調値を、前記相対値で除算する映像信号補正部とを備えている。 In order to solve the above problems, the image display device according to one aspect of the present disclosure has a display area in which a plurality of pixels are arranged, a display panel for displaying an image based on an input video signal, and the display area. A plurality of independently lit light sources that illuminate the plurality of pixels in the above, a luminance distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources that illuminate each of the plurality of pixels, and attention. When only one of the plurality of light sources corresponding to a pixel is lit, the maximum brightness of the illumination light applied to the pixel of interest is set to 1, and the relative value with respect to the brightness calculated by the brightness distribution calculation unit. It is provided with a correction coefficient calculation unit for calculating the above, and a video signal correction unit for dividing the gradation value of the pixel of interest based on the input video signal by the relative value.
　本開示の一態様に係る画像表示装置は、複数の画素が配列された表示領域を有し、映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源と、前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出部と、前記複数の光源の内、注目画素に対応する光源を含む一部の光源のみが点灯した時に当該注目画素に照射される照明光の最大の輝度を最大輝度とし、前記輝度分布算出部によって算出された輝度が前記最大輝度より大きい画素があった場合に、前記輝度分布算出部によって算出される輝度が前記最大輝度以下となるように、前記一部の光源の出力を低下させる光源データ補正部とを備えている。 The image display device according to one aspect of the present disclosure has a display area in which a plurality of pixels are arranged, and independently illuminates a display panel that displays an image based on a video signal and the plurality of pixels in the display area. Corresponds to a plurality of light sources that can be turned on, a brightness distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources that is irradiated to each of the plurality of pixels, and a pixel of interest among the plurality of light sources. When only a part of the light sources including the light source to be turned on are turned on, the maximum brightness of the illumination light applied to the pixel of interest is set as the maximum brightness, and there are pixels whose brightness calculated by the brightness distribution calculation unit is larger than the maximum brightness. In this case, a light source data correction unit that reduces the output of some of the light sources is provided so that the brightness calculated by the brightness distribution calculation unit is equal to or less than the maximum brightness.
　本開示の一態様に係る画像表示装置の制御方法は、複数の画素が配列された表示領域を有し、映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源とを備える画像表示装置の制御方法であって、前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出工程と、注目画素に対応する、前記複数の光源の内の１つのみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を１として、前記輝度分布算出工程で算出した輝度についての相対値を算出する補正係数算出工程と、前記入力映像信号に基づく前記注目画素の階調値を、前記相対値で除算する映像信号補正工程とを含んでいる。 The control method of the image display device according to one aspect of the present disclosure has a display area in which a plurality of pixels are arranged, and illuminates a display panel for displaying an image based on a video signal and the plurality of pixels in the display area. , A method of controlling an image display device including a plurality of light sources that can be turned on independently, and calculating a brightness distribution for calculating the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels. The brightness calculated in the brightness distribution calculation step, where the maximum brightness of the illumination light applied to the attention pixel is set to 1 when only one of the plurality of light sources corresponding to the process and the attention pixel is lit. It includes a correction coefficient calculation step of calculating a relative value of the above, and a video signal correction step of dividing the gradation value of the pixel of interest based on the input video signal by the relative value.
　本開示の一態様に係る画像表示装置の制御方法は、複数の画素が配列された表示領域を有し、映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源とを備える画像表示装置の制御方法であって、前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出工程と、前記複数の光源の内、注目画素に対応する光源を含む一部の光源のみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を最大輝度とし、前記輝度分布算出工程で算出された輝度が前記最大輝度より大きい画素があった場合に、前記輝度分布算出工程で算出される輝度が前記最大輝度以下となるように、前記一部の光源の出力を低下させる光源データ補正工程とを含んでいる。 The control method of the image display device according to one aspect of the present disclosure has a display area in which a plurality of pixels are arranged, illuminates a display panel for displaying an image based on a video signal, and the plurality of pixels in the display area. , A method of controlling an image display device including a plurality of light sources that can be turned on independently, and calculating a brightness distribution for calculating the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels. In the step, when only a part of the light sources including the light source corresponding to the pixel of interest is turned on among the plurality of light sources, the maximum brightness of the illumination light applied to the pixel of interest is set as the maximum brightness, and the brightness distribution is calculated. A light source that reduces the output of some of the light sources so that the brightness calculated in the brightness distribution calculation step is equal to or less than the maximum brightness when there is a pixel whose brightness calculated in the step is greater than the maximum brightness. It includes a data correction step.
　本開示の一態様によれば、独立して点灯可能な複数の光源の点灯状態によらず、入力映像信号に対する忠実性の高い画像を表示できる。 According to one aspect of the present disclosure, an image having high fidelity to an input video signal can be displayed regardless of the lighting state of a plurality of light sources that can be turned on independently.
本開示の実施形態１に係る表示装置の構成を示すブロック図である。It is a block diagram which shows the structure of the display device which concerns on Embodiment 1 of this disclosure. 表示装置におけるローカルディミング機能を用いた表示処理の一例を説明するための図である。It is a figure for demonstrating an example of a display process using a local dimming function in a display device. 複数の発光領域が発光した場合の輝度分布を示す図である。It is a figure which shows the luminance distribution when a plurality of light emitting regions emit light. 上記表示装置における処理の流れの一例を示すフローチャートである。It is a flowchart which shows an example of the processing flow in the said display device. 上記表示装置の効果を説明するための図であり、（ａ）は入力映像信号の階調値を示すグラフであり、（ｂ）は当該入力映像信号の階調値に応じて発光した発光領域の輝度分布を示すグラフであり、（ｃ）は映像信号補正部による補正後の液晶透過率を示すグラフであり、（ｄ）は表示部３における表示輝度を示すグラフである。It is a figure for demonstrating the effect of the said display device, FIG. (C) is a graph showing the liquid crystal transmittance after correction by the video signal correction unit, and (d) is a graph showing the display brightness in the display unit 3. 表示部に全面１００％白のベタ画像を表示した状態を示す図である。It is a figure which shows the state which displayed the solid image of 100% white on the whole surface on the display part. 図６のＡ―Ｂ間の入力映像信号を透過率に換算したもの、ＢＬの輝度分布、補正後の液晶透過率、および表示部における実際の表示輝度を順に示した図である。It is a figure which converted the input video signal between A and B of FIG. 6 into a transmittance, the luminance distribution of BL, the liquid crystal transmittance after correction, and the actual display luminance in the display part in order. ０％黒背景に１００％白ウインドウが、発光領域のサイズよりやや小さめに、発光領域の中心から図面の右側にずれた位置に表示された状態を示す図である。It is a figure which shows the state which the 100% white window is displayed at the position shifted to the right side of a drawing from the center of a light emitting area slightly smaller than the size of a light emitting area on a 0% black background. 図８の状態のＢＬの輝度分布を表わす図である。It is a figure which shows the luminance distribution of BL in the state of FIG. 図６のＡ―Ｂ間の入力信号を透過率に換算した値、ＢＬの輝度分布、映像信号補正部による補正後の液晶透過率、および表示部における実際の表示輝度を順に示したものである。The values obtained by converting the input signals between A and B in FIG. 6 into transmittance, the brightness distribution of BL, the liquid crystal transmittance corrected by the video signal correction unit, and the actual display brightness on the display unit are shown in order. .. （ａ）は、従来の表示装置に小さいウインドウを表示したときの当該ウインドウの輝度を示す図であり、（ｂ）は、表示装置に小さいウインドウを表示したときの当該ウインドウの輝度を示す図である。(A) is a diagram showing the brightness of the window when a small window is displayed on the conventional display device, and (b) is a diagram showing the brightness of the window when the small window is displayed on the display device. is there. 実施形態２に係る表示装置の構成を示すブロック図である。It is a block diagram which shows the structure of the display device which concerns on Embodiment 2. 表示装置における処理の流れの一例を示すフローチャートである。It is a flowchart which shows an example of the processing flow in a display device. 実施形態３に係る表示装置の構成を示すブロック図である。It is a block diagram which shows the structure of the display device which concerns on Embodiment 3. 表示装置における処理の流れの一例を示すフローチャートである。It is a flowchart which shows an example of the processing flow in a display device.
　〔実施形態１〕
　以下、本開示の一実施形態について、詳細に説明する。図１は、本実施形態に係る表示装置１の構成を示すブロック図である。図１に示すように、表示装置１は、入力映像信号が示す画像である入力画像を表示する画像表示装置であり、主制御部２、表示部３および記憶部４を備える。表示装置１は、携帯情報端末であってもよいし、据え置き型の表示装置であってもよい。 [Embodiment 1]
Hereinafter, one embodiment of the present disclosure will be described in detail. FIG. 1 is a block diagram showing a configuration of a display device 1 according to the present embodiment. As shown in FIG. 1, the display device 1 is an image display device that displays an input image which is an image indicated by an input video signal, and includes a main control unit 2, a display unit 3, and a storage unit 4. The display device 1 may be a portable information terminal or a stationary display device.
　主制御部２は、表示装置１を統括的に制御する装置であり、特に画像処理装置として機能する。記憶部４は、主制御部２が処理するプログラム等を記憶する。 The main control unit 2 is a device that comprehensively controls the display device 1, and particularly functions as an image processing device. The storage unit 4 stores a program or the like processed by the main control unit 2.
　表示部３は、主制御部２で処理された入力画像を表示する。本実施形態では、表示部３は、液晶ディスプレイである。具体的には、表示部３は、表示パネル３１、表示パネル駆動部３２、ＬＥＤバックライト３３（以下、ＢＬ３３と称する）、およびＬＥＤ駆動部３４（以下、ＢＬ駆動部３４と称する）を備える。 The display unit 3 displays the input image processed by the main control unit 2. In the present embodiment, the display unit 3 is a liquid crystal display. Specifically, the display unit 3 includes a display panel 31, a display panel drive unit 32, an LED backlight 33 (hereinafter referred to as BL33), and an LED drive unit 34 (hereinafter referred to as BL drive unit 34).
　表示パネル３１は、複数の画素３５が配列された表示領域を有し、入力された映像信号（入力映像信号）に基づく画像を表示するパネルであり、本実施形態では液晶表示パネルである。入力映像信号は、動画を示す信号であってもよいし、静止画を示す信号であってもよい。 The display panel 31 has a display area in which a plurality of pixels 35 are arranged and displays an image based on an input video signal (input video signal), and is a liquid crystal display panel in the present embodiment. The input video signal may be a signal indicating a moving image or a signal indicating a still image.
　表示パネル駆動部３２は、後述する映像信号補正部２５が生成した液晶データが示す出力値で表示パネル３１を駆動させる。ＢＬ駆動部３４は、ＢＬ制御部２７から受け取ったバックライトデータ（以下、ＢＬデータ）に従って、ＢＬ３３の点灯を制御する。これらの駆動制御により、表示パネル３１に入力画像が表示される。 The display panel drive unit 32 drives the display panel 31 with the output value indicated by the liquid crystal data generated by the video signal correction unit 25, which will be described later. The BL drive unit 34 controls the lighting of the BL 33 according to the backlight data (hereinafter, BL data) received from the BL control unit 27. By these drive controls, the input image is displayed on the display panel 31.
　図２は、表示装置１におけるローカルディミング機能を用いた表示処理の一例を説明するための図である。図２に示す入力画像においては、階調値が高い領域が、白に近い色で示されている。 FIG. 2 is a diagram for explaining an example of display processing using the local dimming function in the display device 1. In the input image shown in FIG. 2, a region having a high gradation value is shown in a color close to white.
　図２に示すように、ＢＬ３３は、表示パネル３１の表示領域における複数の画素３５を照らす、独立して点灯可能な光源としての複数の発光領域（ＬＥＤ）３６を備えている。表示装置１は、発光領域３６毎に点灯制御を行うローカルディミング機能を有している。発光領域３６は、マトリクス状に配置されており、図２に示す例では、ＢＬ３３は、ｍ×ｎ個の発光領域３６に分割されている。各発光領域３６が、１つのＬＥＤによって実現されていてもよいし、各発光領域３６に、２以上のＬＥＤが設けられていても構わない。ＢＬ３３が備える光源は、ＬＥＤに限定されず、他の種類の発光素子であってもよい。 As shown in FIG. 2, the BL 33 includes a plurality of light emitting areas (LEDs) 36 as independently lit light sources that illuminate the plurality of pixels 35 in the display area of the display panel 31. The display device 1 has a local dimming function that controls lighting for each light emitting region 36. The light emitting regions 36 are arranged in a matrix, and in the example shown in FIG. 2, the BL 33 is divided into m × n light emitting regions 36. Each light emitting area 36 may be realized by one LED, or two or more LEDs may be provided in each light emitting area 36. The light source included in the BL33 is not limited to the LED, and may be another type of light emitting element.
　図１に示すように、主制御部２は、ガンマ変換部２１、ＢＬデータ算出部（光源データ算出部）２２、輝度分布算出部２３、補正係数算出部２４、映像信号補正部２５、逆ガンマ変換部２６およびＢＬ制御部２７を備えている。 As shown in FIG. 1, the main control unit 2 includes a gamma conversion unit 21, a BL data calculation unit (light source data calculation unit) 22, a brightness distribution calculation unit 23, a correction coefficient calculation unit 24, a video signal correction unit 25, and an inverse gamma. It includes a conversion unit 26 and a BL control unit 27.
　ガンマ変換部２１は、入力映像信号を、当該入力映像信号のフォーマットに従い、ルックアップテーブル等を参照することによりガンマ変換し、リニアの信号にする。 The gamma conversion unit 21 gamma-converts the input video signal according to the format of the input video signal by referring to a look-up table or the like to obtain a linear signal.
　ＢＬデータ算出部２２は、ガンマ変換された映像信号に基づいて、複数の発光領域３６の出力（ＬＥＤ点灯率）をそれぞれ算出し、当該出力を示すバックライトデータ（ＢＬデータ）（図２参照）を生成する。具体的には、入力画像を発光領域３６に対応する領域（分割表示領域と称する）に分割し、各分割表示領域に含まれる画素３５の階調値のうち、最大の階調値に対応するように、当該発光領域３６の出力を決定する。 The BL data calculation unit 22 calculates the outputs (LED lighting rates) of the plurality of light emitting regions 36 based on the gamma-converted video signal, and the backlight data (BL data) indicating the outputs (see FIG. 2). To generate. Specifically, the input image is divided into an area corresponding to the light emitting area 36 (referred to as a divided display area), and corresponds to the maximum gradation value among the gradation values of the pixels 35 included in each divided display area. As described above, the output of the light emitting region 36 is determined.
　なお、本明細書において、「画素３５の階調値」と表現した場合には、入力映像信号に含まれている複数の階調値のうち、注目する画素３５に対応する階調値を意味する。入力映像信号に含まれている複数の階調値と複数の画素３５とは、一対一に対応しているものとする。 In addition, in this specification, when it expresses as "the gradation value of a pixel 35", it means the gradation value corresponding to the pixel 35 of interest among a plurality of gradation values included in an input video signal. To do. It is assumed that the plurality of gradation values and the plurality of pixels 35 included in the input video signal have a one-to-one correspondence.
　ＢＬ制御部２７は、ＢＬデータ算出部２２が生成したＢＬデータをＢＬ駆動部３４へ出力することにより、ＢＬ３３の駆動を制御する。 The BL control unit 27 controls the drive of the BL 33 by outputting the BL data generated by the BL data calculation unit 22 to the BL drive unit 34.
　輝度分布算出部２３は、複数の画素３５のそれぞれに照射される、複数の発光領域３６からの照明光（バックライト光）の輝度を算出する。具体的には、輝度分布算出部２３は、ＢＬデータ、および、光の拡散の仕方を数値で表したデータである輝度拡散関数（ＰＳＦ、Point Spread Function）に基づいて、ＢＬ３３の輝度分布を算出する。 The brightness distribution calculation unit 23 calculates the brightness of the illumination light (backlight light) from the plurality of light emitting regions 36 that is irradiated to each of the plurality of pixels 35. Specifically, the luminance distribution calculation unit 23 calculates the luminance distribution of BL33 based on the luminance data and the luminance diffusion function (PSF, Point Spread Function) which is data expressing how the light is diffused numerically. To do.
　補正係数算出部２４は、表示パネル３１が備える複数の画素３５のうちの１つの画素３５（注目画素）に対応する１つの発光領域３６のみが点灯した時に、当該注目画素に照射される照明光の最大輝度を１として、輝度分布算出部２３が算出した照明光の輝度についての相対値（以下、補正係数と称する）を当該注目画素について算出する。補正係数算出部２４は、この処理を、表示パネル３１が備える全ての画素３５について行う。 The correction coefficient calculation unit 24 illuminates the attention pixel when only one light emitting region 36 corresponding to one pixel 35 (attention pixel) of the plurality of pixels 35 included in the display panel 31 is lit. A relative value (hereinafter, referred to as a correction coefficient) for the brightness of the illumination light calculated by the brightness distribution calculation unit 23 is calculated for the pixel of interest, with the maximum brightness of 1 being 1. The correction coefficient calculation unit 24 performs this process on all the pixels 35 included in the display panel 31.
　逆ガンマ変換部２６は、ガンマ変換部２１によって生成されたリニアの映像信号を、表示パネル３１の表示ガンマに合わせて逆ガンマ変換する。 The inverse gamma conversion unit 26 converts the linear video signal generated by the gamma conversion unit 21 into an inverse gamma according to the display gamma of the display panel 31.
　映像信号補正部２５は、ガンマ変換された映像信号が示す、各画素３５の階調値を、当該画素３５に対応する補正係数を用いて補正する。すなわち、映像信号補正部２５は、入力映像信号に基づく注目画素の階調値を前記補正係数で除算する。例えば、映像信号補正部２５は、各画素３５の階調値を当該画素３５に対応する補正係数で除算する。そのため、補正係数が１より大きい場合には、補正対象となる注目画素の階調値は小さくなり、補正係数が１より小さい場合には、注目画素の階調値は大きくなる。なお、映像信号補正部２５は、各画素３５の階調値に、補正係数の逆数をかけてもよい。 The video signal correction unit 25 corrects the gradation value of each pixel 35 indicated by the gamma-converted video signal by using the correction coefficient corresponding to the pixel 35. That is, the video signal correction unit 25 divides the gradation value of the pixel of interest based on the input video signal by the correction coefficient. For example, the video signal correction unit 25 divides the gradation value of each pixel 35 by the correction coefficient corresponding to the pixel 35. Therefore, when the correction coefficient is larger than 1, the gradation value of the pixel of interest to be corrected becomes small, and when the correction coefficient is smaller than 1, the gradation value of the pixel of interest becomes large. The video signal correction unit 25 may multiply the gradation value of each pixel 35 by the reciprocal of the correction coefficient.
　さらに、映像信号補正部２５は、逆ガンマ変換部２６によって逆ガンマ変換された映像信号の情報を参照して最終的な映像信号を生成し、液晶データとして表示パネル駆動部３２に出力する。当該液晶データは、液晶透過率を示すデータである。 Further, the video signal correction unit 25 generates a final video signal by referring to the information of the video signal converted to the reverse gamma by the reverse gamma conversion unit 26, and outputs the final video signal as liquid crystal data to the display panel drive unit 32. The liquid crystal data is data indicating the liquid crystal transmittance.
　図３は、複数の発光領域３６が発光した場合の輝度分布を示す図である。補正係数算出部２４および映像信号補正部２５における処理の意義について説明する。図３に示すように、最大輝度で発光する２つの発光領域３６が発光した場合には、当該２つの発光領域３６からの照明光によりピーク５１・５２がそれぞれ生じる。その結果、これら２つの発光領域３６からの照明光を受ける画素３５（注目画素）における照明光の輝度は、ピーク５３として表現できる。つまり、当該画素３５における照明光の輝度は、符号５４で示す分だけ上昇する。なお、符号５５で示す領域が１つの発光領域３６に相当する。 FIG. 3 is a diagram showing a luminance distribution when a plurality of light emitting regions 36 emit light. The significance of the processing in the correction coefficient calculation unit 24 and the video signal correction unit 25 will be described. As shown in FIG. 3, when the two light emitting regions 36 that emit light at the maximum brightness emit light, the peaks 51 and 52 are generated by the illumination light from the two light emitting regions 36, respectively. As a result, the brightness of the illumination light in the pixel 35 (the pixel of interest) that receives the illumination light from these two light emitting regions 36 can be expressed as a peak 53. That is, the brightness of the illumination light in the pixel 35 increases by the amount indicated by the reference numeral 54. The region indicated by reference numeral 55 corresponds to one light emitting region 36.
　補正係数算出部２４は、ピーク５３の最大輝度で注目画素が照明された場合でも、１つの発光領域３６の最大輝度で照明された場合と同じ表示輝度を実現するように、入力映像信号に基づく各画素３５の階調値を補正するための補正係数を算出する。例えば、符号５４で示す上昇分が１．２であれば、補正係数算出部２４は、１．２を補正係数として算出する。この場合、映像信号補正部２５は、ガンマ変換された映像信号が示す、注目画素の階調値を１．２で除算する。 The correction coefficient calculation unit 24 is based on the input video signal so that even when the pixel of interest is illuminated with the maximum brightness of the peak 53, the same display brightness as when illuminated with the maximum brightness of one light emitting region 36 is realized. A correction coefficient for correcting the gradation value of each pixel 35 is calculated. For example, if the increase indicated by reference numeral 54 is 1.2, the correction coefficient calculation unit 24 calculates 1.2 as the correction coefficient. In this case, the video signal correction unit 25 divides the gradation value of the pixel of interest indicated by the gamma-converted video signal by 1.2.
　以下、本実施形態に係る表示装置１における処理（制御方法）の流れの一例について、図４を用いて説明する。図４は、表示装置１における処理の流れの一例を示すフローチャートである。図４に示すように、ガンマ変換部２１は、入力映像信号を外部の装置から受信すると、当該入力映像信号のフォーマットに対応したルックアップテーブル等を参照することにより、当該入力映像信号をガンマ変換し、リニアの信号にする（Ｓ１）。 Hereinafter, an example of the flow of processing (control method) in the display device 1 according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the processing flow in the display device 1. As shown in FIG. 4, when the gamma conversion unit 21 receives the input video signal from an external device, it gamma-converts the input video signal by referring to a look-up table or the like corresponding to the format of the input video signal. Then, it becomes a linear signal (S1).
　逆ガンマ変換部２６は、ガンマ変換部２１によって生成されたリニアの映像信号を、表示パネル３１の表示ガンマに合わせて逆ガンマ変換する（Ｓ２）。 The inverse gamma conversion unit 26 performs inverse gamma conversion in accordance with the display gamma of the display panel 31 from the linear video signal generated by the gamma conversion unit 21 (S2).
　一方、ＢＬデータ算出部２２は、ガンマ変換部２１によってガンマ変換された映像信号に基づいて、複数の発光領域３６の出力（ＬＥＤ点灯率）をそれぞれ算出し、当該出力を示すＢＬデータを生成する（Ｓ３）。ＢＬデータ算出部２２は、生成したＢＬデータを輝度分布算出部２３およびＢＬ制御部２７へ出力する。 On the other hand, the BL data calculation unit 22 calculates the outputs (LED lighting rates) of the plurality of light emitting regions 36 based on the video signal gamma-converted by the gamma conversion unit 21, and generates BL data indicating the outputs. (S3). The BL data calculation unit 22 outputs the generated BL data to the luminance distribution calculation unit 23 and the BL control unit 27.
　輝度分布算出部２３は、前記ＢＬデータおよびＰＳＦに基づいて、複数の画素３５のそれぞれに照射される、複数の発光領域３６からの照明光の輝度（ＢＬ３３の輝度分布）を算出する（Ｓ４）（輝度分布算出工程）。輝度分布算出部２３は、前記輝度分布を示すデータを補正係数算出部２４へ出力する。 The brightness distribution calculation unit 23 calculates the brightness of the illumination light (brightness distribution of BL 33) from the plurality of light emitting regions 36 to be irradiated to each of the plurality of pixels 35 based on the BL data and the PSF (S4). (Brightness distribution calculation process). The luminance distribution calculation unit 23 outputs data indicating the luminance distribution to the correction coefficient calculation unit 24.
　ここで、複数の画素３５のうちの注目画素に対応する１つの発光領域３６のみが点灯した時に、当該注目画素に照射される照明光の最大輝度を１とする。補正係数算出部２４は、輝度分布算出部２３が算出した照明光の輝度についての相対値である補正係数を当該注目画素について算出する（補正係数算出工程）。補正係数算出部２４は、この処理を、表示パネル３１が備える全ての画素３５について行う（Ｓ５）。補正係数算出部２４は、算出した各画素３５の補正係数を映像信号補正部２５へ出力する。 Here, when only one light emitting region 36 corresponding to the pixel of interest among the plurality of pixels 35 is lit, the maximum brightness of the illumination light emitted to the pixel of interest is set to 1. The correction coefficient calculation unit 24 calculates a correction coefficient, which is a relative value for the brightness of the illumination light calculated by the brightness distribution calculation unit 23, for the pixel of interest (correction coefficient calculation step). The correction coefficient calculation unit 24 performs this process on all the pixels 35 included in the display panel 31 (S5). The correction coefficient calculation unit 24 outputs the calculated correction coefficient of each pixel 35 to the video signal correction unit 25.
　映像信号補正部２５は、補正係数算出部２４から補正係数を受け取ると、ガンマ変換された映像信号が示す各画素３５の階調値を、当該画素３５に対応する補正係数を用いて補正する（Ｓ６）（映像信号補正工程）。 When the video signal correction unit 25 receives the correction coefficient from the correction coefficient calculation unit 24, the video signal correction unit 25 corrects the gradation value of each pixel 35 indicated by the gamma-converted video signal by using the correction coefficient corresponding to the pixel 35 ( S6) (Video signal correction step).
　さらに、映像信号補正部２５は、逆ガンマ変換部２６によって逆ガンマ変換された映像信号の情報を参照して最終的な映像信号を生成し、液晶透過率を示す液晶データとして表示パネル駆動部３２に出力する。 Further, the video signal correction unit 25 generates a final video signal by referring to the information of the video signal converted to the reverse gamma by the reverse gamma conversion unit 26, and displays the display panel drive unit 32 as liquid crystal data indicating the liquid crystal transmittance. Output to.
　表示パネル駆動部３２は、映像信号補正部２５が生成した液晶データが示す出力値で表示パネル３１を駆動させる（Ｓ７）。 The display panel drive unit 32 drives the display panel 31 with the output value indicated by the liquid crystal data generated by the video signal correction unit 25 (S7).
　一方、ＢＬ制御部２７は、ＢＬデータ算出部２２が生成したＢＬデータをＢＬ駆動部３４へ出力することにより、ＢＬ３３の駆動を制御する（Ｓ８）。これらの駆動制御により、表示パネル３１に入力画像が表示される。 On the other hand, the BL control unit 27 controls the drive of the BL 33 by outputting the BL data generated by the BL data calculation unit 22 to the BL drive unit 34 (S8). By these drive controls, the input image is displayed on the display panel 31.
　次に、本実施形態に係る表示装置１の効果について、図５を用いて説明する。図５は、表示装置１の効果を説明するための図であり、（ａ）は入力映像信号の階調値を示すグラフであり、（ｂ）は当該入力映像信号の階調値に応じて発光した発光領域３６の輝度分布を示すグラフであり、（ｃ）は映像信号補正部２５による補正後の液晶透過率を示すグラフであり、（ｄ）は表示部３における表示輝度を示すグラフである。 Next, the effect of the display device 1 according to the present embodiment will be described with reference to FIG. 5A and 5B are diagrams for explaining the effect of the display device 1, FIG. 5A is a graph showing the gradation value of the input video signal, and FIG. 5B is a graph showing the gradation value of the input video signal according to the gradation value of the input video signal. It is a graph which shows the luminance distribution of the light emitting region 36 which emitted light, (c) is a graph which shows the liquid crystal transmittance after correction by a video signal correction part 25, (d) is a graph which shows display brightness in display part 3. is there.
　図５の（ａ）～（ｄ）に示すように、５つの横に並んだ発光領域３６のそれぞれが、図５の（ａ）に示す入力映像信号の階調値（透過率換算）（図５の（ｂ）における破線５６）に応じて発光したとする。この場合、実際の輝度分布は、図５の（ｂ）における実線５７のようになる。対応する分割表示領域に含まれる複数の画素３５のうちの、最大の階調値を実現するように当該発光領域３６が発光するためである。 As shown in FIGS. 5A to 5D, each of the five horizontally arranged light emitting regions 36 is a gradation value (transmittance conversion) of the input video signal shown in FIG. 5A (FIG. 5). It is assumed that light is emitted according to the broken line 56) in (b) of 5. In this case, the actual luminance distribution is as shown by the solid line 57 in FIG. 5B. This is because the light emitting area 36 emits light so as to realize the maximum gradation value among the plurality of pixels 35 included in the corresponding divided display area.
　補正係数算出部２４は、発光領域３６を１単体で点灯したときの、注目画素に照射される照明光の最大輝度を１としたときの、照明光の輝度の相対値を各画素３５について算出する。映像信号補正部２５は、映像信号に含まれる、各画素３５の階調値を、前記相対値（補正係数）で除算する。 The correction coefficient calculation unit 24 calculates the relative value of the brightness of the illumination light for each pixel 35 when the maximum brightness of the illumination light applied to the pixel of interest is 1 when the light emitting region 36 is lit by itself. To do. The video signal correction unit 25 divides the gradation value of each pixel 35 included in the video signal by the relative value (correction coefficient).
　このように映像処理することにより、液晶透過率は、図５の（ｃ）に示すグラフのようになる。表示部３における実際の表示輝度は、図５の（ｂ）に示す実線５７と液晶透過率との積になるため、図５の（ｄ）に示すように、入力映像信号が示す入力階調値と同じ表示輝度を実現することができる。 By performing the image processing in this way, the liquid crystal transmittance becomes as shown in the graph shown in FIG. 5 (c). Since the actual display luminance in the display unit 3 is the product of the solid line 57 shown in FIG. 5 (b) and the liquid crystal transmittance, the input gradation indicated by the input video signal is shown in FIG. 5 (d). The same display brightness as the value can be realized.
　すなわち、ある画素３５に照射される照明光の輝度が、最大輝度を超えて必要以上に高まった場合でも、当該画素３５の階調値を適切に補正することができる。その結果、複数の発光領域３６の内の、点灯している発光領域３６の数に関わらず、入力映像信号に対する忠実性の高い画像を表示できる。 That is, even when the brightness of the illumination light applied to a certain pixel 35 exceeds the maximum brightness and becomes higher than necessary, the gradation value of the pixel 35 can be appropriately corrected. As a result, an image having high fidelity to the input video signal can be displayed regardless of the number of lit light emitting regions 36 among the plurality of light emitting regions 36.
　さらに表示装置１の効果について、別の観点から説明する。 Further, the effect of the display device 1 will be explained from another viewpoint.
　図６は、表示部３に全面１００％白のベタ画像を表示した状態を示す図である。図７は図６のＡ―Ｂ間の入力映像信号を透過率に換算したもの（「入力」と表示）、ＢＬ３３の輝度分布（「ＢＬ輝度分布」と表示）、補正後の液晶透過率、および表示部３における実際の表示輝度を順に示した図である。便宜上、Ａ―Ｂ間の発光領域３６の数は５であり、１つの発光領域３６に２０個の画素３５が含まれているものとする。 FIG. 6 is a diagram showing a state in which a solid image of 100% white on the entire surface is displayed on the display unit 3. FIG. 7 shows the input video signal between A and B in FIG. 6 converted into transmittance (displayed as “input”), the luminance distribution of BL33 (displayed as “BL luminance distribution”), and the corrected liquid crystal transmittance. It is a figure which showed the actual display luminance in order in the display part 3. For convenience, it is assumed that the number of light emitting regions 36 between A and B is 5, and one light emitting region 36 includes 20 pixels 35.
　入力映像信号が表示領域の全域に渡って１００％であるため、ＢＬ３３は全域にわたって１００％で点灯し、その輝度分布は発光領域３６が単体で光った時の輝度の最大値に対して１２０％になるものとする。したがって、各画素３５の階調値の補正は、１÷１．２となり、凡そ０．８３（８３％）の透過率になる。実際の表示輝度は、ＢＬ３３の輝度と液晶透過率との積になるため、１．２×０．８３＝１となり、入力された映像信号に従った表示となる。 Since the input video signal is 100% over the entire display area, the BL33 is lit at 100% over the entire area, and its brightness distribution is 120% of the maximum brightness when the light emitting area 36 shines alone. It shall be. Therefore, the correction of the gradation value of each pixel 35 is 1 / 1.2, and the transmittance is about 0.83 (83%). Since the actual display brightness is the product of the brightness of BL33 and the liquid crystal transmittance, 1.2 × 0.83 = 1, and the display follows the input video signal.
　図８は、０％黒背景に１００％白ウインドウが、発光領域３６のサイズよりやや小さめに、発光領域３６の中心から図面の右側にずれた位置に表示された状態を示す図である。図９は、図８の状態のＢＬ３３の輝度分布を表わす図である。ＢＬ３３において、白ウインドウに対応する発光領域３６とその周囲の発光領域３６とが点灯している。 FIG. 8 is a diagram showing a state in which a 100% white window on a 0% black background is displayed at a position slightly smaller than the size of the light emitting area 36 and shifted to the right side of the drawing from the center of the light emitting area 36. FIG. 9 is a diagram showing the luminance distribution of BL33 in the state of FIG. In BL33, the light emitting area 36 corresponding to the white window and the light emitting area 36 around the light emitting area 36 are lit.
　図１０は図８のＡ―Ｂ間の入力信号を透過率に換算した値（「入力」と表示）、ＢＬ３３の輝度分布（「ＢＬ輝度分布」と表示）、映像信号補正部２５による補正後の液晶透過率、および表示部３における実際の表示輝度を順に示したものである。図６の場合と同様にＡ―Ｂ間には５つの発光領域３６が含まれており、１つの発光領域３６に２０個の画素３５が含まれているものとする。 FIG. 10 shows a value obtained by converting the input signal between A and B in FIG. 8 into transmittance (displayed as “input”), the luminance distribution of BL33 (displayed as “BL luminance distribution”), and after correction by the video signal correction unit 25. The liquid crystal transmittance of the above and the actual display brightness in the display unit 3 are shown in order. As in the case of FIG. 6, it is assumed that five light emitting regions 36 are included between A and B, and that one light emitting region 36 includes 20 pixels 35.
　入力映像信号が示す画像には、中央の発光領域３６（中央エリアと称する）の中央よりやや右寄りにウインドウがある。ここで、中央エリアは１００％、中央エリアの右側の発光領域３６は８０％、中央エリアの左側の発光領域３６は５０％、その他の発光領域３６は０％で光っている。このように光ると中央エリアに対応する画素３５の輝度は１より大きくなるため、輝度が１より大きくなる画素３５の階調を下げることにより、所望とする輝度を実現することができる。 The image indicated by the input video signal has a window slightly to the right of the center of the central light emitting area 36 (referred to as the central area). Here, the central area is 100%, the light emitting area 36 on the right side of the central area is 80%, the light emitting area 36 on the left side of the central area is 50%, and the other light emitting areas 36 are 0%. Since the brightness of the pixel 35 corresponding to the central area becomes larger than 1 when shining in this way, the desired brightness can be realized by lowering the gradation of the pixel 35 whose brightness becomes larger than 1.
　図１１の（ａ）は、従来の表示装置３００に小さいウインドウ６１を表示したときの当該ウインドウの輝度を示す図であり、図１１の（ｂ）は、表示装置１に小さいウインドウ６２を表示したときの当該ウインドウの輝度を示す図である。 FIG. 11A is a diagram showing the brightness of the window when the small window 61 is displayed on the conventional display device 300, and FIG. 11B is a diagram showing the small window 62 on the display device 1. It is a figure which shows the brightness of the said window at the time.
　通常、ローカルディミングバックライトを用いた従来の液晶表示装置では、全面白映像が入力された場合、すなわち、ＬＥＤが全発光領域に渡って最大発光強度で発光した場合を最大輝度として液晶データの補正が行われる。この場合、小さいウインドウ表示のときには、発光する領域が少なくなるため、バックライトが暗くなり、表示される輝度も小さくなってしまう。そのため、ウインドウ６１は、グレーで表示される。 Normally, in a conventional liquid crystal display device using a local dimming backlight, the liquid crystal data is corrected with the maximum brightness when a completely white image is input, that is, when the LED emits light at the maximum emission intensity over the entire emission region. Is done. In this case, in the case of a small window display, the light emitting area is reduced, so that the backlight becomes dark and the displayed brightness becomes small. Therefore, the window 61 is displayed in gray.
　これに対して表示装置１では、上述した原理により、全面に白映像を表示したときでも、小さいウインドウを表示したときでも同じ輝度で映像を表示することができる。すなわち、図１１の（ｂ）に示す例において、ウインドウ６２は白で表示される。 On the other hand, in the display device 1, according to the above-mentioned principle, the image can be displayed with the same brightness regardless of whether the white image is displayed on the entire surface or a small window is displayed. That is, in the example shown in FIG. 11B, the window 62 is displayed in white.
　また、ローカルディミングバックライトを用いていない従来の液晶表示装置では、ウインドウの大きさによらず、輝度は変わらないが、常に全面のバックライトを発光しているため、消費電力が大きい。また、消費電力を小さくするためには、輝度を低くする必要があるが、表示装置１では、ローカルディミングすることにより消費電力を抑えることができ、コントラストも増加させることができる。 In addition, in the conventional liquid crystal display device that does not use the local dimming backlight, the brightness does not change regardless of the size of the window, but the backlight always emits light on the entire surface, so that the power consumption is large. Further, in order to reduce the power consumption, it is necessary to lower the brightness, but in the display device 1, the power consumption can be suppressed and the contrast can be increased by local dimming.
　〔実施形態２〕
　本開示の他の実施形態について、以下に説明する。なお、説明の便宜上、上記実施形態にて説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を繰り返さない。 [Embodiment 2]
Other embodiments of the present disclosure will be described below. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the above embodiment, and the description will not be repeated.
　図１２は、本実施形態に係る表示装置１Ａの構成を示すブロック図である。図１２に示すように、本実施形態の表示装置１Ａは、表示装置１の構成に加えて、ＢＬ電力補正部（電力補正部）２８を備えている。 FIG. 12 is a block diagram showing the configuration of the display device 1A according to the present embodiment. As shown in FIG. 12, the display device 1A of the present embodiment includes a BL power correction unit (power correction unit) 28 in addition to the configuration of the display device 1.
　ＢＬ電力補正部２８は、ＢＬデータを受信し、ＢＬデータ算出部２２が算出した複数の発光領域３６の出力からＢＬ３３の全体の消費電力を算出する。また、ＢＬ電力補正部２８は、算出した消費電力が所定値を超えている場合に、当該消費電力が所定値を超えないように、ＢＬデータにおける少なくとも一部の発光領域３６の出力を低下させる。 The BL power correction unit 28 receives the BL data and calculates the total power consumption of the BL 33 from the outputs of the plurality of light emitting regions 36 calculated by the BL data calculation unit 22. Further, when the calculated power consumption exceeds a predetermined value, the BL power correction unit 28 reduces the output of at least a part of the light emitting region 36 in the BL data so that the power consumption does not exceed the predetermined value. ..
　例えば、ＢＬ電力補正部２８は、ＢＬ３３の消費電力が、前記所定値以下となるように、ＢＬデータにおける各発光領域３６の出力値を一律の割合で、または出力値が高いほど低下度が高まるように低下させる。発光領域３６の出力値を低下させる様式は、特に限定されない。 For example, the BL power correction unit 28 reduces the output value of each light emitting region 36 in the BL data at a uniform rate or as the output value increases so that the power consumption of the BL 33 becomes equal to or less than the predetermined value. To lower it. The mode for reducing the output value of the light emitting region 36 is not particularly limited.
　消費電力の前記所定値とは、例えば、ＢＬ３３が全面点灯した状態において、各画素３５の輝度が、前記最大輝度、すなわち発光領域３６の１つのみが点灯した時に、当該発光領域３６からの照明光を受ける画素３５における照明光の輝度の最大値を超えない消費電力である。ただし、当該所定値は、表示装置１Ａの仕様に応じて適宜設定されればよく、特に限定されない。 The predetermined value of power consumption is, for example, the illumination from the light emitting region 36 when the brightness of each pixel 35 is the maximum brightness, that is, when only one of the light emitting regions 36 is lit in a state where the BL 33 is entirely lit. The power consumption does not exceed the maximum value of the brightness of the illumination light in the pixel 35 that receives the light. However, the predetermined value may be appropriately set according to the specifications of the display device 1A, and is not particularly limited.
　なお、輝度分布算出部２３は、実施形態１と同様に、ＢＬデータ算出部２２から出力されたＢＬデータに基づいて、複数の画素３５のそれぞれに照射される、複数の発光領域３６からの照明光の輝度を算出してもよい。また、輝度分布算出部２３は、ＢＬ電力補正部２８から出力された補正後のＢＬデータを受け取り、前記照明光の輝度を算出してもよい。 As in the first embodiment, the luminance distribution calculation unit 23 illuminates each of the plurality of pixels 35 based on the BL data output from the BL data calculation unit 22 from the plurality of light emitting regions 36. The brightness of the light may be calculated. Further, the brightness distribution calculation unit 23 may receive the corrected BL data output from the BL power correction unit 28 and calculate the brightness of the illumination light.
　図１３は、表示装置１Ａにおける処理の流れの一例を示すフローチャートである。図１３に示すフローチャートにおいて、Ｓ１１～Ｓ１７の各ステップは、図４に示すＳ１～Ｓ７の各ステップと同様のものである。 FIG. 13 is a flowchart showing an example of the processing flow in the display device 1A. In the flowchart shown in FIG. 13, each step of S11 to S17 is the same as each step of S1 to S7 shown in FIG.
　ＢＬデータ算出部２２は、ガンマ変換部２１によってガンマ変換された映像信号に基づいて、ＢＬデータを生成する（Ｓ１３）。ＢＬデータ算出部２２は、生成したＢＬデータを輝度分布算出部２３およびＢＬ電力補正部２８へ出力する。 The BL data calculation unit 22 generates BL data based on the video signal gamma-converted by the gamma conversion unit 21 (S13). The BL data calculation unit 22 outputs the generated BL data to the luminance distribution calculation unit 23 and the BL power correction unit 28.
　ＢＬ電力補正部２８は、ＢＬデータを受信すると、当該ＢＬデータが示す複数の発光領域３６の出力からＢＬ３３の全体の消費電力を算出する（Ｓ１８）。 When the BL power correction unit 28 receives the BL data, the BL power correction unit 28 calculates the total power consumption of the BL 33 from the outputs of the plurality of light emitting regions 36 indicated by the BL data (S18).
　ＢＬ電力補正部２８は、算出した消費電力が所定値を超えている場合に（Ｓ１９にてＹＥＳ）、当該消費電力が所定値を超えないように、ＢＬデータにおける少なくとも一部の発光領域３６の出力を低下させる（Ｓ２０）。また、ＢＬ電力補正部２８は、補正したＢＬデータをＢＬ制御部２７へ出力する。 When the calculated power consumption exceeds the predetermined value (YES in S19), the BL power correction unit 28 covers at least a part of the light emitting region 36 in the BL data so that the power consumption does not exceed the predetermined value. The output is reduced (S20). Further, the BL power correction unit 28 outputs the corrected BL data to the BL control unit 27.
　一方、ＢＬ電力補正部２８は、算出した消費電力が所定値を超えていない場合には（Ｓ１９にて、ＮＯ）、ＢＬデータを補正せずにＢＬ制御部２７へ出力する。 On the other hand, if the calculated power consumption does not exceed the predetermined value (NO in S19), the BL power correction unit 28 outputs the BL data to the BL control unit 27 without correcting it.
　ＢＬ制御部２７は、ＢＬ電力補正部２８から受信したＢＬデータをＢＬ駆動部３４へ出力することにより、ＢＬ３３の駆動を制御する（Ｓ２１）。 The BL control unit 27 controls the drive of the BL 33 by outputting the BL data received from the BL power correction unit 28 to the BL drive unit 34 (S21).
　以上のように、表示装置１Ａによれば、図６に示したようにＢＬ３３が全面点灯したときなど、ＢＬ３３の消費電力が所定値を超えた場合に、ＢＬ電力補正部２８は、当該消費電力が所定値以下となるようにＢＬデータの補正を行う。一方、図８に示したように、小さいウインドウのみが表示される状態では、ＢＬ３３の消費電力は所定値を超えないため、ＢＬ電力補正部２８は、ＢＬデータの補正を行わない。そのため、消費電力を所定の範囲内に抑えつつ、入力映像信号に対する忠実性の高い画像を表示できる。 As described above, according to the display device 1A, when the power consumption of the BL 33 exceeds a predetermined value, such as when the BL 33 is entirely lit as shown in FIG. 6, the BL power correction unit 28 consumes the power. BL data is corrected so that is equal to or less than a predetermined value. On the other hand, as shown in FIG. 8, in the state where only a small window is displayed, the power consumption of the BL 33 does not exceed a predetermined value, so that the BL power correction unit 28 does not correct the BL data. Therefore, it is possible to display an image having high fidelity to the input video signal while suppressing the power consumption within a predetermined range.
　〔実施形態３〕
　本開示の他の実施形態について、以下に説明する。図１４は、本実施形態に係る表示装置１Ｂの構成を示すブロック図である。図１４に示すように、本実施形態の表示装置１Ｂは、表示装置１の構成に加えて、ＢＬデータ補正部（光源データ補正部）２９を備えている。 [Embodiment 3]
Other embodiments of the present disclosure will be described below. FIG. 14 is a block diagram showing the configuration of the display device 1B according to the present embodiment. As shown in FIG. 14, the display device 1B of the present embodiment includes a BL data correction unit (light source data correction unit) 29 in addition to the configuration of the display device 1.
　なお、表示装置１Ｂにおいては、補正係数算出部２４は必須の構成要素ではないため、補正係数算出部２４を省略してもよい。この場合、映像信号補正部２５は、補正係数を用いた階調値の補正は行わず、従来と同様に、輝度分布算出部２３が算出した輝度分布に基づいて、映像信号の階調値を補正すればよい。 Since the correction coefficient calculation unit 24 is not an indispensable component in the display device 1B, the correction coefficient calculation unit 24 may be omitted. In this case, the video signal correction unit 25 does not correct the gradation value using the correction coefficient, and similarly to the conventional case, the video signal correction unit 25 calculates the gradation value of the video signal based on the luminance distribution calculated by the luminance distribution calculation unit 23. It should be corrected.
　本実施形態では、複数の発光領域３６（光源）の内、注目画素に対応する発光領域３６を含む一部の発光領域３６のみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を最大輝度と称する。注目画素に対応する発光領域３６を含む一部の発光領域３６のみが点灯するとは、注目画素に対応する発光領域３６（中央発光領域）と、その周囲の発光領域３６（周辺発光領域）とが点灯することを意味する。 In the present embodiment, when only a part of the light emitting areas 36 including the light emitting area 36 corresponding to the pixel of interest is lit among the plurality of light emitting areas 36 (light sources), the maximum amount of illumination light emitted to the pixel of interest is the maximum. The brightness is called the maximum brightness. When only a part of the light emitting area 36 including the light emitting area 36 corresponding to the pixel of interest is lit, the light emitting area 36 (central light emitting area) corresponding to the pixel of interest and the light emitting area 36 around the light emitting area 36 (peripheral light emitting area) are lit. It means to light up.
　周辺発光領域として予め設定される発光領域３６は、中央発光領域の周囲（上下、左右、斜め方向）に位置する発光領域３６であってもよいし、さらにその外側を取り囲む発光領域３６を周辺発光領域に含めてもよい。周辺発光領域は、例えば、ＰＳＦに基づく、発光領域３６の発光点の大きさまたは分布形状を考慮して設定すればよい。中央発光領域および周辺発光領域は、例えば、５×５個の発光領域３６である。 The light emitting region 36 preset as the peripheral light emitting region may be a light emitting region 36 located around the central light emitting region (up / down, left / right, diagonal direction), and the light emitting region 36 surrounding the outer side thereof may be peripherally emitted. It may be included in the area. The peripheral light emitting region may be set in consideration of, for example, the size or distribution shape of the light emitting points of the light emitting region 36 based on PSF. The central light emitting region and the peripheral light emitting region are, for example, 5 × 5 light emitting regions 36.
　輝度分布算出部２３は、複数の画素３５のそれぞれに照射される、複数の発光領域３６からの照明光の輝度を算出する。 The brightness distribution calculation unit 23 calculates the brightness of the illumination light from the plurality of light emitting regions 36 to be irradiated to each of the plurality of pixels 35.
　ＢＬデータ補正部２９は、輝度分布算出部２３によって算出された照明光の輝度が前記最大輝度より大きい画素３５（注目画素）があった場合に、当該照明光の輝度が前記最大輝度以下となるように、前記一部の発光領域３６（すなわち、中央発光領域および周辺発光領域）の出力を低下させる。換言すれば、ＢＬデータ補正部２９は、輝度分布算出部２３が算出した照明光の輝度が前記最大輝度より大きい画素３５があった場合に、当該照明光の輝度が前記最大輝度以下となるように、前記一部の発光領域３６についてＢＬデータを補正する。 The BL data correction unit 29 makes the brightness of the illumination light equal to or less than the maximum brightness when there is a pixel 35 (attention pixel) whose brightness of the illumination light calculated by the brightness distribution calculation unit 23 is larger than the maximum brightness. As described above, the output of the partial light emitting region 36 (that is, the central light emitting region and the peripheral light emitting region) is reduced. In other words, the BL data correction unit 29 makes the brightness of the illumination light equal to or less than the maximum brightness when there is a pixel 35 whose brightness of the illumination light calculated by the brightness distribution calculation unit 23 is larger than the maximum brightness. In addition, BL data is corrected for the part of the light emitting region 36.
　例えば、ＢＬデータ補正部２９は、前記最大輝度を１としたときの、注目画素の照明光の輝度の相対値を算出し、当該相対値で、前記一部の発光領域３６の出力値を除算する。ＢＬデータ補正部２９におけるＢＬデータの補正方法は、この方法に限定されず、注目画素の照明光の輝度が前記最大輝度以下となる方法であればよい。 For example, the BL data correction unit 29 calculates the relative value of the brightness of the illumination light of the pixel of interest when the maximum brightness is 1, and divides the output value of the part of the light emitting region 36 by the relative value. To do. The method for correcting BL data in the BL data correction unit 29 is not limited to this method, and any method may be used as long as the brightness of the illumination light of the pixel of interest is equal to or less than the maximum brightness.
　図１５は、表示装置１Ｂにおける処理の流れの一例を示すフローチャートである。図１５に示すフローチャートにおいて、Ｓ３１～Ｓ３３の各ステップは、図４に示すＳ１～Ｓ３の各ステップと同様のものである。 FIG. 15 is a flowchart showing an example of the processing flow in the display device 1B. In the flowchart shown in FIG. 15, each step of S31 to S33 is the same as each step of S1 to S3 shown in FIG.
　輝度分布算出部２３は、ステップＳ４における処理と同様に、ＢＬデータおよびＰＳＦに基づいて、ＢＬ３３の輝度分布を算出する（Ｓ３４）。輝度分布算出部２３は、前記輝度分布を示すデータをＢＬデータ補正部２９へ出力する。 The luminance distribution calculation unit 23 calculates the luminance distribution of BL33 based on the BL data and the PSF, as in the process in step S4 (S34). The brightness distribution calculation unit 23 outputs data indicating the brightness distribution to the BL data correction unit 29.
　ＢＬデータ補正部２９は、前記輝度分布のデータを受け取ると、各画素３５の照明光の輝度が前記最大輝度「１」以下かどうかを判定する。注目画素の輝度が「１」以下でない場合（Ｓ３５にてＮＯ）、ＢＬデータ補正部２９は、当該照明光の輝度が前記最大輝度「１」以下となるように、当該注目画素に対応する中央発光領域および周辺発光領域の出力を低下させるためにＢＬデータを補正する（Ｓ３６）（光源データ補正工程）。ＢＬデータ補正部２９は、補正したＢＬデータを輝度分布算出部２３へ出力し、再度ステップＳ３４およびステップＳ３５の処理を行う。 Upon receiving the brightness distribution data, the BL data correction unit 29 determines whether or not the brightness of the illumination light of each pixel 35 is the maximum brightness "1" or less. When the brightness of the attention pixel is not "1" or less (NO in S35), the BL data correction unit 29 performs the center corresponding to the attention pixel so that the brightness of the illumination light becomes the maximum brightness "1" or less. BL data is corrected in order to reduce the output of the light emitting region and the peripheral light emitting region (S36) (light source data correction step). The BL data correction unit 29 outputs the corrected BL data to the luminance distribution calculation unit 23, and performs the processes of steps S34 and S35 again.
　一方、各画素３５の照明光の輝度が前記最大輝度「１」以下である場合（Ｓ３５にてＹＥＳ）、ＢＬデータ補正部２９は、ＢＬデータを補正せずに補正係数算出部２４およびＢＬ制御部２７へ出力する。 On the other hand, when the brightness of the illumination light of each pixel 35 is equal to or less than the maximum brightness "1" (YES in S35), the BL data correction unit 29 performs the correction coefficient calculation unit 24 and the BL control without correcting the BL data. Output to unit 27.
　Ｓ３７～Ｓ４０の各ステップは、図４に示すＳ５～Ｓ８の各ステップと同様のものである。なお、ステップＳ４０においてＢＬ制御部２７は、ＢＬデータ補正部２９からＢＬデータを取得する。 Each step of S37 to S40 is the same as each step of S5 to S8 shown in FIG. In step S40, the BL control unit 27 acquires BL data from the BL data correction unit 29.
　以上のように、表示装置１Ｂでは、ＢＬデータ補正部２９は、照明光の輝度が前記最大輝度より大きい画素３５があった場合に、当該画素３５の照明光の輝度が前記最大輝度以下となるように、当該画素３５に対応する中央発光領域およびその周辺の発光領域の出力を低下させる。 As described above, in the display device 1B, when there is a pixel 35 whose illumination light brightness is larger than the maximum brightness, the BL data correction unit 29 makes the illumination light brightness of the pixel 35 equal to or less than the maximum brightness. As described above, the output of the central light emitting region corresponding to the pixel 35 and the light emitting region around the central light emitting region is reduced.
　そのため、ある画素３５に照射される照明光の輝度が、最大輝度を超えて必要以上に高まった場合でも、当該画素３５に対応する一部の発光領域３６の出力を低下させることにより、入力映像信号に対する忠実性の高い画像を表示できる。すなわち、複数の発光領域３６の点灯状態によらず、入力映像信号に対する忠実性の高い画像を表示できる。また、当該処理により、表示装置１Ｂの消費電力を、表示装置１よりも低下させることができる。 Therefore, even if the brightness of the illumination light applied to a certain pixel 35 exceeds the maximum brightness and becomes unnecessarily high, the output of a part of the light emitting region 36 corresponding to the pixel 35 is reduced to reduce the output of the input image. An image with high fidelity to the signal can be displayed. That is, an image having high fidelity to the input video signal can be displayed regardless of the lighting state of the plurality of light emitting regions 36. Further, by this processing, the power consumption of the display device 1B can be made lower than that of the display device 1.
　〔ソフトウェアによる実現例〕
　表示装置１・１Ａ・１Ｂの制御ブロック（特に、ＢＬデータ算出部２２、輝度分布算出部２３、補正係数算出部２４、映像信号補正部２５、ＢＬ制御部２７、ＢＬ電力補正部２８およびＢＬデータ補正部２９）は、集積回路（ＩＣチップ）等に形成された論理回路（ハードウェア）によって実現してもよいし、ソフトウェアによって実現してもよい。 [Example of realization by software]
Control blocks of display devices 1, 1A, 1B (particularly, BL data calculation unit 22, brightness distribution calculation unit 23, correction coefficient calculation unit 24, video signal correction unit 25, BL control unit 27, BL power correction unit 28, and BL data. The correction unit 29) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.
　後者の場合、表示装置１・１Ａ・１Ｂは、各機能を実現するソフトウェアであるプログラムの命令を実行するコンピュータを備えている。このコンピュータは、例えば少なくとも１つのプロセッサ（制御装置）を備えていると共に、上記プログラムを記憶したコンピュータ読み取り可能な少なくとも１つの記録媒体を備えている。そして、上記コンピュータにおいて、上記プロセッサが上記プログラムを上記記録媒体から読み取って実行することにより、本開示の目的が達成される。上記プロセッサとしては、例えばＣＰＵ（Central Processing Unit）を用いることができる。上記記録媒体としては、「一時的でない有形の媒体」、例えば、ＲＯＭ（Read Only Memory）等の他、テープ、ディスク、カード、半導体メモリ、プログラマブルな論理回路などを用いることができる。また、上記プログラムを展開するＲＡＭ（Random Access Memory）などをさらに備えていてもよい。また、上記プログラムは、該プログラムを伝送可能な任意の伝送媒体（通信ネットワークや放送波等）を介して上記コンピュータに供給されてもよい。なお、本開示の一態様は、上記プログラムが電子的な伝送によって具現化された、搬送波に埋め込まれたデータ信号の形態でも実現され得る。 In the latter case, the display devices 1, 1A, and 1B include a computer that executes a program instruction, which is software that realizes each function. The computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present disclosure. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, in addition to a “non-temporary tangible medium” such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (RandomAccessMemory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present disclosure can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.
　そのため、本開示の各態様に係る表示装置１・１Ａ・１Ｂの制御装置である主制御部２は、コンピュータによって実現してもよく、この場合には、コンピュータを主制御部２が備える各部（ソフトウェア要素）として動作させることにより主制御部２をコンピュータにて実現させる表示装置の制御プログラム、およびそれを記録したコンピュータ読み取り可能な記録媒体も、本開示の範疇に入る。 Therefore, the main control unit 2 which is the control device of the display devices 1, 1A, and 1B according to each aspect of the present disclosure may be realized by a computer. In this case, each unit (in this case) including the computer. A control program of a display device that realizes the main control unit 2 on a computer by operating as a software element) and a computer-readable recording medium that records the control program are also included in the scope of the present disclosure.
　本開示は上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本開示の技術的範囲に含まれる。さらに、各実施形態にそれぞれ開示された技術的手段を組み合わせることにより、新しい技術的特徴を形成することができる。 The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

Claims (5)

  1. 　複数の画素が配列された表示領域を有し、入力映像信号に基づく画像を表示する表示パネルと、
    　前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源と、
    　前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出部と、
    　注目画素に対応する、前記複数の光源の内の１つのみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を１とし、前記輝度分布算出部が算出した輝度についての相対値を算出する補正係数算出部と、
    　前記入力映像信号に基づく前記注目画素の階調値を、前記相対値で除算する映像信号補正部とを備えることを特徴とする画像表示装置。     A display panel that has a display area in which a plurality of pixels are arranged and displays an image based on an input video signal,
    A plurality of independently lit light sources that illuminate the plurality of pixels in the display area,
    A luminance distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels, and a luminance distribution calculation unit.
    When only one of the plurality of light sources corresponding to the pixel of interest is lit, the maximum brightness of the illumination light applied to the pixel of interest is set to 1, and the relative brightness calculated by the brightness distribution calculation unit is set to 1. A correction coefficient calculation unit that calculates the value, and
    An image display device including a video signal correction unit that divides the gradation value of the pixel of interest based on the input video signal by the relative value.
  2. 　前記入力映像信号に基づいて、前記複数の光源の出力を算出する光源データ算出部と、
    　前記光源データ算出部が算出した前記出力から求められる消費電力が所定値を超えている場合に、当該消費電力が所定値を超えないように前記出力を低下させる電力補正部とをさらに備えることを特徴とする請求項１に記載の画像表示装置。     A light source data calculation unit that calculates the outputs of the plurality of light sources based on the input video signal,
    When the power consumption obtained from the output calculated by the light source data calculation unit exceeds a predetermined value, it is further provided with a power correction unit that reduces the output so that the power consumption does not exceed the predetermined value. The image display device according to claim 1.
  3. 　複数の画素が配列された表示領域を有し、映像信号に基づく画像を表示する表示パネルと、
    　前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源と、
    　前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出部と、
    　前記複数の光源の内、注目画素に対応する光源を含む一部の光源のみが点灯した時に当該注目画素に照射される照明光の最大の輝度を最大輝度とし、前記輝度分布算出部によって算出された輝度が前記最大輝度より大きい画素があった場合に、前記輝度分布算出部によって算出される輝度が前記最大輝度以下となるように、前記一部の光源の出力を低下させる光源データ補正部とを備えることを特徴とする画像表示装置。     A display panel that has a display area in which a plurality of pixels are arranged and displays an image based on a video signal,
    A plurality of independently lit light sources that illuminate the plurality of pixels in the display area,
    A luminance distribution calculation unit that calculates the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels, and a luminance distribution calculation unit.
    Among the plurality of light sources, the maximum brightness of the illumination light emitted to the attention pixel when only a part of the light sources including the light source corresponding to the attention pixel is turned on is set as the maximum brightness, and is calculated by the brightness distribution calculation unit. A light source data correction unit that reduces the output of some of the light sources so that the brightness calculated by the brightness distribution calculation unit is equal to or less than the maximum brightness when there is a pixel whose brightness is greater than the maximum brightness. An image display device comprising.
  4. 　複数の画素が配列された表示領域を有し、入力映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源とを備える画像表示装置の制御方法であって、
    　前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出工程と、
    　注目画素に対応する、前記複数の光源の内の１つのみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を１として、前記輝度分布算出工程で算出した輝度についての相対値を算出する補正係数算出工程と、
    　前記入力映像信号に基づく前記注目画素の階調値を、前記相対値で除算する映像信号補正工程とを含むことを特徴とする制御方法。     An image including a display panel having a display area in which a plurality of pixels are arranged and displaying an image based on an input video signal, and a plurality of independently lit light sources that illuminate the plurality of pixels in the display area. It is a control method of the display device.
    A luminance distribution calculation step for calculating the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels,
    When only one of the plurality of light sources corresponding to the pixel of interest is lit, the maximum brightness of the illumination light applied to the pixel of interest is set to 1, and the relative brightness calculated in the brightness distribution calculation step is set to 1. The correction coefficient calculation process to calculate the value and
    A control method comprising a video signal correction step of dividing a gradation value of the pixel of interest based on the input video signal by the relative value.
  5. 　複数の画素が配列された表示領域を有し、映像信号に基づく画像を表示する表示パネルと、前記表示領域における前記複数の画素を照らす、独立して点灯可能な複数の光源とを備える画像表示装置の制御方法であって、
    　前記複数の画素のそれぞれに照射される、前記複数の光源からの照明光の輝度を算出する輝度分布算出工程と、
    　前記複数の光源の内、注目画素に対応する光源を含む一部の光源のみが点灯した時に、当該注目画素に照射される照明光の最大の輝度を最大輝度とし、前記輝度分布算出工程で算出された輝度が前記最大輝度より大きい画素があった場合に、前記輝度分布算出工程で算出される輝度が前記最大輝度以下となるように、前記一部の光源の出力を低下させる光源データ補正工程とを含むことを特徴とする制御方法。     An image display including a display panel having a display area in which a plurality of pixels are arranged and displaying an image based on a video signal, and a plurality of independently lit light sources that illuminate the plurality of pixels in the display area. It is a control method of the device
    A luminance distribution calculation step for calculating the brightness of illumination light from the plurality of light sources irradiated to each of the plurality of pixels,
    When only a part of the light sources including the light source corresponding to the pixel of interest is turned on, the maximum brightness of the illumination light applied to the pixel of interest is set as the maximum brightness, and the calculation is performed in the brightness distribution calculation step. A light source data correction step of reducing the output of some of the light sources so that the brightness calculated in the brightness distribution calculation step is equal to or less than the maximum brightness when there is a pixel whose brightness is larger than the maximum brightness. A control method comprising and.
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