# US 9,439,266 B2 · Method for adjusting pixel data based on the duty ratio history of the backlight in order to compensate for the temperature of the backlight

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- Number: US 9,439,266 B2
- Document ID: US9439266B2
- Status: Granted
- Kind: B2
- Application number: 14/080,001
- Filed: 2013-11-14
- Published: 2014-03-13
- Granted: 2016-09-06
- Earliest claimed: 2008-12-09
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Hyung-Ku Kang; Hyuk-Hwan Kim; Dae-Gwang Jang; Yu-Han Bae; Hyeon-Yong Jang
- Web page: https://patentgrep.com/patent/US9439266B2

## CPC

- H05B 47/10: Controlling the light source
- G09G 3/342: {using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines}
- G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix}
- G09G 5/10: Intensity circuits
- H05B 45/24: using electrical feedback from LEDs or from LED modules
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/041: Temperature compensation
- 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 2320/066: for control of contrast
- G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- 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 light source device includes a light source module having a light-emitting block, an image analysis part, a duty ratio calculation part, a duty ratio determination part and a signal generation part. The image analysis part extracts representative luminance data of the light-emitting block based on pixel data. The duty ratio calculation part calculates duty ratio data of the light-emitting block based on the representative luminance data. The duty ratio determination part generates determined duty ratio data of the light-emitting block based on the duty ratio data from a first period, and the signal generation part generates a driving signal having a duty ratio corresponding to the determined duty ratio data to drive the light-emitting block.

## Claims

### Claim 1

A method of driving a light source device including a light source module having a light-emitting block, the method comprising:
determining duty ratio data of the light-emitting block by using pixel data;
extracting fixed duty ratio data based on the duty ratio data from a first period;
calculating fixed luminance data corresponding to a temperature of the light-emitting block by using the fixed duty ratio data;
generating a driving signal having a duty ratio corresponding to the duty ratio data; and
driving the light-emitting block with the driving signal,
wherein the calculating the fixed luminance data comprises:
storing luminance data corresponding to duty ratio data sampled from measured fixed duty ratio data, and
calculating the fixed luminance data by linear interpolation of the measured fixed duty ratio data.

### Claim 2 (depends on 1)

The method of claim 1, wherein said calculating the fixed luminance data comprises linear interpolation using the duty ratio data and the fixed duty ratio data.

### Claim 3

A light source device comprising:
a light source module including a light-emitting block;
a duty ratio determination part which determines duty ratio data by using representative luminance data of the light-emitting block based on pixel data;
a fixed duty ratio extracting part which extracts fixed duty ratio data based on the duty ratio data from a first period;
a fixed luminance calculation part which calculates fixed luminance data corresponding to a temperature of the light-emitting block based on the fixed duty ratio data; and
a signal generation part which generates a driving signal having a duty ratio corresponding to the determined duty ratio data to drive the light-emitting block,
wherein the fixed luminance calculation part includes a storage part which stores luminance data corresponding to duty ratio data sampled from measured fixed duty ratio data, and
the fixed luminance calculation part calculates the fixed luminance data by linear interpolation of the measured fixed duty ratio data.

### Claim 4 (depends on 3)

The light source device of claim 3, further comprising a duty ratio storage part which stores the duty ratio data during the first period, wherein the duty ratio storage part periodically stores most significant J-bit data of the duty ratio data every I frames (where I and J are natural numbers) during the first period.

### Claim 5

A display apparatus comprising:
a display panel which displays an image;
a light source module including a light-emitting block and which provides the display panel with light;
a light source driving device which extracts fixed duty ratio data based on duty ratio data of the light-emitting block from a first period, and which calculates fixed luminance data of the light-emitting block by using the duty ratio data and the fixed duty ratio data, the light source driving device configured to drive the light-emitting block by using a driving signal having a duty ratio corresponding to the duty ratio data;
a compensation part which generates a compensated pixel data of an image block corresponding to the light-emitting block based on the fixed luminance data; and
a panel driving part which drives the display panel using the compensated pixel data,
wherein the fixed luminance calculation part includes a storage part which stores the luminance data corresponding to duty ratio data sampled from measured fixed duty ratio data, and
the fixed luminance calculation part calculates the fixed luminance data by linear interpolation of the measure fixed duty ratio data.

### Claim 6 (depends on 5)

The display apparatus of claim 5, wherein the light source driving device includes:
a duty ratio determination part which determines the duty ratio data based on representative luminance data of the light-emitting block and pixel data;
a fixed duty ratio extracting part which extracts the fixed duty ratio data by using the duty ratio data from the first period;
a fixed luminance calculation part which calculates the fixed luminance data corresponding to a temperature of the light-emitting block based on the fixed duty ratio data; and
a signal generation part which generates the driving signal having the duty ratio corresponding to the determined duty ratio data to drive the light-emitting block.