# US 11,443,703 B2 · Method for driving display device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,443,703 B2
- Document ID: US11443703B2
- Status: Granted
- Kind: B2
- Application number: 17/125,977
- Filed: 2020-12-17
- Published: 2022-06-23
- Granted: 2022-09-13
- Earliest claimed: 2020-12-17
- Assignees: Himax Technologies Limited
- Applicants: Himax Technologies Limited
- Inventors: Tung-Ying Wu
- Web page: https://patentgrep.com/patent/US11443703B2

## CPC

- G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix}
- G09G 3/2007: {Display of intermediate tones}
- G09G 2320/064: by time modulation of the brightness of the illumination source
- G09G 2320/0646: Modulation of illumination source brightness and image signal correlated to each other
- 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 device for driving a backlight assembly of a display device includes: a block division unit for dividing the input image into plural blocks and a duty cycle determination unit. The duty cycle determination unit is used for: generating a histogram of gray levels of pixels of each block; obtaining a high gray level and a median gray level of each block according to the histogram; obtaining a high gray quantity based on the high gray level and a median gray quantity of the median gray level of each block according to the histogram; obtaining a weight value of each block according to the high gray level, the high gray quantity, the median gray quantity, and a lookup table; and calculating a duty cycle of a driving signal of each block according to the weight value, the high gray level, and the median gray level.

## Claims

### Claim 1

A method for driving a display device, comprising:
receiving an input image;
dividing the input image into a plurality of blocks;
generating a histogram of gray levels of pixels of each of the blocks;
obtaining a high gray level and a median gray level of each of the blocks according to the histogram;
calculating an image high gray level and an image median gray level of the input image according to the high gray level and the median gray level of each of the blocks;
inputting a difference between the image high gray level and the image median gray level into a gain lookup table to obtain a duty gain;
obtaining an updated duty cycle of a driving signal of each of the blocks according to the duty gain;
obtaining a gain value of each of the blocks according to the updated duty cycle; and
compensating the input image by using the gain value of each of the blocks.

### Claim 2 (depends on 1)

The method of claim 1, wherein obtaining the high gray level of each of the blocks comprises:
setting a quantity threshold (X);
statistically analyzing top X brightest pixels of the pixels; and
determining a gray level of Xth brightest pixel is the high gray level.

### Claim 3 (depends on 1)

The method of claim 1, wherein the median gray level of each of the blocks is an average of gray levels of pixels of each of the blocks.

### Claim 4 (depends on 1)

The method of claim 1, wherein the image high gray level is a maximum value of the high gray levels of the blocks.

### Claim 5 (depends on 1)

The method of claim 1, wherein the image median gray level is an average value of the median gray levels of the blocks.

### Claim 6 (depends on 1)

The method of claim 1, wherein as the difference between the image high gray level and the image median gray level is closer to 191, the duty gain is closer to 1.

### Claim 7 (depends on 1)

The method of claim 1, wherein the updated duty cycle is obtaining by adding a first duty cycle to a product of the duty gain and a difference between a second duty cycle and the first duty cycle.

### Claim 8 (depends on 7)

The method of claim 7, wherein the second duty cycle is not less than the first duty cycle.

### Claim 9 (depends on 1)

The method of claim 1, further comprising:
obtaining a high gray quantity based on the high gray level and a median gray quantity of the median gray level of each of the blocks according to the histogram;
obtaining a weight value of each of the blocks according to the high gray level, the high gray quantity, the median gray quantity, and a lookup table;
calculating a duty cycle of the driving signal of each of the blocks according to the weight value, the high gray level, and the median gray level; and
driving a backlight assembly of the display device with the updated duty cycle of the driving signal of each of the blocks.

### Claim 10 (depends on 9)

The method of claim 9, wherein the high gray quantity is a number of the pixels with brightness from a maximum gray level to the high gray level.

### Claim 11 (depends on 9)

The method of claim 9, wherein the weight value of each of the blocks is obtained by inputting the high gray level and a normalized value of a ratio of the high gray quantity to the median gray quantity into the lookup table.

### Claim 12 (depends on 11)

The method of claim 11, wherein as the high gray level or the normalized value is greater, the weight value is greater.

### Claim 13 (depends on 9)

The method of claim 9, wherein the duty cycle is a sum of a product of the high gray level and the weight value and a product of the median gray level and a difference between 1 and the weight value.