# US 12,190,830 B2 · Display device with variable emission luminance for individual division areas of backlight, control method of a display device, and non-transitory computer-readable medium

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- Number: US 12,190,830 B2
- Document ID: US12190830B2
- Status: Granted
- Kind: B2
- Application number: 18/358,319
- Filed: 2023-07-25
- Published: 2024-02-15
- Granted: 2025-01-07
- Earliest claimed: 2022-08-09
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Koji Mito
- Web page: https://patentgrep.com/patent/US12190830B2

## CPC

- G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)}
- G09G 3/342: {using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines}
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 3/2025: {the sub-frames having all the same time duration}
- G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix}
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/0686: with two or more screen areas displaying information with different brightness or colours
- G09G 2340/16: Determination of a pixel data signal depending on the signal applied in the previous frame
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

A display device includes a backlight consisting of a plurality of division areas and a display panel. Emission luminance for each division area is calculated based on input image data, a correction value for correcting the input image data is calculated based on the emission luminance, the input image data is corrected based on the calculated correction value, the transmittance of the display panel is controlled based on the corrected image data, and light emission of each division area is controlled based on the calculated emission luminance. One frame period of the input image consists of a plurality of subframe periods, and a process of calculating the correction value for correcting the input image data based on the emission luminance is divided into a plurality of partial processes, which are sequentially performed by executing each partial process in each subframe period.

## Claims

### Claim 1

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) calculate a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period,
wherein the emission luminance for the plurality of division areas calculated in a previous frame period is stored in a memory, and
wherein each partial process includes a process of determining emission luminance of division areas other than the division areas for which emission luminance has been calculated before a current subframe period of a current frame period among the plurality of division areas of the backlight on the basis of the stored emission luminance calculated in the previous frame period.

### Claim 2 (depends on 1)

The display device according to claim 1, wherein the input image data comprises a plurality of subframes, and each partial process includes a process of determining emission luminance for the division area corresponding to each subframe on the basis of image data of each subframe.

### Claim 3 (depends on 1)

The display device according to claim 1, wherein the input image data comprises a plurality of correction target areas, and each partial process includes a process of calculating a correction value for correcting image data of each correction target area.

### Claim 4 (depends on 1)

The display device according to claim 1, wherein the input image data comprises a plurality of correction target areas, and each partial process includes a process of calculating a correction value for correcting image data of each correction target area, and
wherein, in each partial process, the division area located at a position of the correction target area and the division area for which the emission luminance is determined on the basis of emission luminance calculated in the previous frame period are not adjacent to each other.

### Claim 5 (depends on 1)

The display device according to claim 1, wherein the input image data comprises a plurality of subframes and the input image data comprises a plurality of correction target areas, and each partial process includes a process of determining emission luminance for the division area corresponding to each subframe on the basis of image data of each subframe and calculating a correction value for correcting image data of each correction target area, and
wherein, in each partial process, a position of the subframe and a position of the correction target area are the same.

### Claim 6 (depends on 1)

The display device according to claim 1, wherein the input image data comprises a plurality of subframes and the input image data comprises a plurality of correction target areas, and each partial process includes a process of determining emission luminance for the division area corresponding to each subframe on the basis of image data of each subframe and calculating a correction value for correcting image data of each correction target area, and
wherein, in each partial process, a position of the subframe and a position of the correction target area are different from each other.

### Claim 7 (depends on 1)

The display device according to claim 1, wherein the process of calculating the correction value for correcting the input image data on the basis of the emission luminance includes a process of estimating a luminance distribution of light from the backlight emitted to the display panel on the basis of the emission luminance, and
wherein the input image data comprises a plurality of correction target areas, and each partial process includes a process of estimating a luminance distribution in each correction target area and a process of calculating a correction value for correcting image data of each correction target area on the basis of the estimated luminance distribution in each correction target area.

### Claim 8 (depends on 1)

The display device according to claim 1, wherein the transmittance of the display panel and light emission of the backlight are variable for every frame period on the basis of the calculated emission luminance and the correction value.

### Claim 9 (depends on 1)

The display device according to claim 1, wherein the transmittance of the display panel and light emission of the backlight are variable for every subframe period on the basis of the emission luminance and the correction value calculated in each partial process.

### Claim 10 (depends on 1)

The display device according to claim 1, wherein one frame period of the input image data comprises M subframe periods, and a partial process executed in an N-th (N=1 to M) subframe period among the plurality of partial processes includes a process of:
(a) dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe; and
(b) dividing the input image data into M correction target areas in the vertical direction and calculating a correction value for correcting image data of an N-th correction target area from the top.

### Claim 11 (depends on 1)

The display device according to claim 1, wherein one frame period of the input image data comprises M subframe periods,
wherein a partial process executed in an N-th (N=1 to k, 1≤k<M) subframe period among the plurality of partial processes includes a process of dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe, and
wherein a partial process executed in an N-th (N=k+1 to M) subframe period among the plurality of partial processes includes a process of:
(a) dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe; and
(b) dividing the input image data into (M-k) (1≤ k<M) correction target areas in the vertical direction and calculating a correction value for correcting image data of an (N-k)-th correction target area from the top.

### Claim 12

A control method of a display device, the display device including (a) a backlight comprising a plurality of division areas of which emission luminance is variable and (b) a display panel of which transmittance of light emitted from the backlight is variable for each pixel, the control method comprising:
calculating emission luminance for each division areas of the backlight on the basis of input image data;
calculating a correction value for correcting the input image data on the basis of the emission luminance;
correcting the input image data on the basis of the calculated correction value;
controlling the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data; and
controlling light emission of each division areas of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe periods,
wherein the emission luminance for the plurality of division areas calculated in a previous frame period is stored in a memory, and
wherein each partial process includes a process of determining emission luminance of division areas other than the division areas for which emission luminance has been calculated before a current subframe period of a current frame period among the plurality of division areas of the backlight on the basis of the stored emission luminance calculated in the previous frame period.

### Claim 13

A non-transitory computer-readable medium that stores a program for causing a computer to execute a control method of a display device, the display device including (a) a backlight comprising a plurality of division areas of which emission luminance is variable and (b) a display panel of which transmittance of light emitted from the backlight is variable for each pixel, the control method comprising:
calculating emission luminance for each division areas of the backlight on the basis of input image data;
calculating a correction value for correcting the input image data on the basis of the emission luminance;
correcting the input image data on the basis of the calculated correction value;
controlling the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data; and
controlling light emission of each division areas of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe periods,
wherein the emission luminance for the plurality of division areas calculated in a previous frame period is stored in a memory, and
wherein each partial process includes a process of determining emission luminance of division areas other than the division areas for which emission luminance has been calculated before a current subframe period of a current frame period among the plurality of division areas of the backlight on the basis of the stored emission luminance calculated in the previous frame period.

### Claim 14

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) calculate a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period,
wherein the input image data comprises a plurality of subframes and the input image data comprises a plurality of correction target areas, and each partial process includes a process of determining emission luminance for the division area corresponding to each subframe on the basis of image data of each subframe and calculating a correction value for correcting image data of each correction target area, and
wherein, in each partial process, a position of the subframe and a position of the correction target area are the same.

### Claim 15

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) calculate a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period,
wherein the input image data comprises a plurality of subframes and the input image data comprises a plurality of correction target areas, and each partial process includes a process of determining emission luminance for the division area corresponding to each subframe on the basis of image data of each subframe and calculating a correction value for correcting image data of each correction target area, and
wherein, in each partial process, a position of the subframe and a position of the correction target area are different from each other.

### Claim 16

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period,
wherein the process of calculating the correction value for correcting the input image data on the basis of the emission luminance includes a process of estimating a luminance distribution of light from the backlight emitted to the display panel on the basis of the emission luminance, and
wherein the input image data comprises a plurality of correction target areas, and each partial process includes a process of estimating a luminance distribution in each correction target area and a process of calculating a correction value for correcting image data of each correction target area on the basis of the estimated luminance distribution in each correction target area.

### Claim 17

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) calculate a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period, and
wherein one frame period of the input image data comprises M subframe periods, and a partial process executed in an N-th (N=1 to M) subframe period among the plurality of partial processes includes a process of:
(a) dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe; and
(b) dividing the input image data into M correction target areas in the vertical direction and calculating a correction value for correcting image data of an N-th correction target area from the top.

### Claim 18

A display device comprising:
a backlight comprising a plurality of division areas of which emission luminance is variable for each division area;
a display panel of which transmittance of light emitted from the backlight is variable for each pixel;
one or more memories storing instructions; and
one or more processors, the one or more processors executing the instructions to:
(1) calculate emission luminance for each division area of the backlight on the basis of input image data;
(2) calculate a correction value for correcting the input image data on the basis of the emission luminance;
(3) correct the input image data on the basis of the calculated correction value; and
(4) control the transmittance for each pixel of the display panel on the basis of corrected image data acquired through the correcting of the input image data and control light emission of each division area of the backlight on the basis of the calculated emission luminance,
wherein a process of calculating the correction value for correcting the input image data on the basis of the emission luminance is divided into a plurality of partial processes, one frame period of the input image comprises a plurality of subframe periods, and the plurality of partial processes are sequentially performed by executing each partial process in each subframe period,
wherein one frame period of the input image data comprises M subframe periods,
wherein a partial process executed in an N-th (N=1 to k, 1≤k<M) subframe period among the plurality of partial processes includes a process of dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe, and
wherein a partial process executed in an N-th (N=k+1 to M) subframe period among the plurality of partial processes includes a process of:
(a) dividing the input image data into M subframes in a vertical direction and determining emission luminance of the division area corresponding to an N-th subframe from the top on the basis of image data of the N-th subframe; and
(b) dividing the input image data into (M-k) (1≤ k<M) correction target areas in the vertical direction and calculating a correction value for correcting image data of an (N-k)-th correction target area from the top.