Method and device for compensating luminance deviation and display device using the same

Patent metadata

Field	Value
Publication number	US-11636797-B2
Application number	US-202117336744-A
Country	US
Kind code	B2
Filing date	Jun 2, 2021
Priority date	Aug 20, 2020
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

The present disclosure relates to a method and a device for compensating for a luminance deviation. A difference in pixel value of the image capturing device between a first pixel and a second pixel in the screen and a difference in gray scale level between first and second gray scale levels are derived from a captured image at the first gray scale level and a captured image at the second gray scale level which include pixel values of the image capturing device. A pixel value for the second pixel is calculated from the captured image at the first gray scale level.

First claim

What is claimed is:

1. A method for compensating a luminance deviation using an image capturing device which captures an image of a screen of a display panel, the method comprising:
inputting a first input image having first gray scale level data to pixels disposed in the screen of the display panel to capture a first image of the screen, and inputting a second input image having second gray scale level data to the pixels to capture a second image of the screen;
deriving a difference in pixel values of the image capturing device between a first pixel and a second pixel in the screen and a difference in gray scale level between the first and second gray scale levels from a first captured image at the first gray scale level and a second captured image at the second gray scale level which include the pixel values of the image capturing device;
calculating a pixel value for the second pixel from the first captured image at the first gray scale level; and
converting the difference in pixel values of the image capturing device between the first pixel and the second pixel at the first gray scale level to a difference in gray scale levels to derive compensation data of the second pixel using the difference in the pixel values of the image capturing device and the difference in gray scale levels,
wherein each of the pixel values of the image capturing device includes a digital value output from an image sensor pixel of the image capturing device.

2. The method of claim 1 , wherein the first pixel is a reference pixel positioned at a center of the screen.

3. The method of claim 1 , wherein:
an exposure value of the image capturing device is set as an exposure value when the pixel value for the first pixel to which the first gray scale level data is written is a median value in a range of the pixel value; and
wherein the first captured image at the first gray scale level and the second captured image at the second gray scale level are obtained when the images of the screen are captured using the same exposure value.

4. The method of claim 1 , wherein the difference in pixel values of the image capturing device and the difference in gray scale levels between the first and second gray scale levels are derived from a linear line of a linear function.

5. The method of claim 1 , further comprising converting the compensation data to a compensation voltage using a look-up table (LUT) with preset gray scale level and voltage set corresponding to luminance.

6. The method of claim 1 , further comprising:
converting an input image data at the first and second gray scale levels to input voltages; and
multiplying the input voltages and an inclination of a linear function and adding the input voltage and a y-intercept using a result of fitting the input voltages and a compensation voltage as the linear function.

7. The method of claim 6 , further comprising:
adding the input voltages and the compensation voltage to generate output voltages; and
converting the output voltages to compensation gray scale level data using a look-up table (LUT) with preset gray scale level and voltage set corresponding to luminance.

8. A luminance deviation compensation device comprising:
an image capturing device configured to capture an image of a screen of a display panel and output a captured image expressed with pixel values;
a display panel in which pixels are disposed;
a pixel driver configured to write an input image data to the pixels; and
a luminance deviation compensator which generates a first input image having first gray scale level data, receives a first captured image at a first gray scale level from the image capturing device, inputs a second input image having second gray scale level data, and receives a second captured image at a second gray scale level from the image capturing device,
wherein the luminance deviation compensator derives a difference in pixel value of the image capturing device between a first pixel and a second pixel and a difference in gray scale level between the first and second gray scale levels from the first captured image at the first gray scale level and the second captured image at the second gray scale level,
calculates a pixel value for the second pixel from the first captured image at the first gray scale level, and
converts the difference in pixel values of the image capturing device between the first pixel and the second pixel at the first gray scale level to a difference in gray scale levels to derive compensation data of the second pixel using the difference in the pixel values of the image capturing device and the difference in the gray scale levels,
wherein each of the pixel values of the image capturing device includes a digital value output from an image sensor pixel of the image capturing device.

9. The luminance deviation compensation device of claim 8 , wherein the luminance deviation compensator calculates the difference in pixel values of the image capturing device and the difference in gray scale levels between the first and second gray scale levels from a linear line of linear function.

10. The luminance deviation compensation device of claim 8 , wherein the luminance deviation compensator converts the compensation data to a compensation voltage using a look-up table (LUT) with preset gray scale level and voltage set corresponding to luminance.

11. The luminance deviation compensation device of claim 10 , wherein the luminance deviation compensator:
converts the input image data at the first and second gray scale levels to input voltages; and
multiplies the input voltages and an inclination of a linear function and adds the input voltages and a y-intercept using a result of fitting the input voltages and the compensation voltage as the linear function.

12. The luminance deviation compensation device of claim 11 , wherein the luminance deviation compensator:
adds the input voltages and the compensation voltage to generate output voltages; and
converts the output voltages to compensation gray scale level data using the look-up table (LUT).

Assignees

• Lg Display Co Ltd

Inventors

• Park Geon Ho
• Lee Won Yeol
• Heo Cheon

Classifications

• G09G2360/145

  the light originating from the display screen · CPC title

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G2310/027

  Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters · CPC title

• G09G3/3208

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title

• G09G3/2003 Primary

  Display of colours (specific for liquid crystal displays G09G3/3607) · CPC title