Display device and white balance adjusting method thereof

Patent metadata

Field	Value
Publication number	US-2021027727-A1
Application number	US-201716639488-A
Country	US
Kind code	A1
Filing date	Dec 13, 2017
Priority date	Aug 16, 2017
Publication date	Jan 28, 2021
Grant date	—

Abstract

A display device and a white balance adjusting method thereof are provided. The white balance adjusting method comprises: measuring a stimulus value of each of gray scales of each of pixels of a panel; defining a white point voltage and a white chromaticity; calculating a white chromaticity difference between a bright state white point voltage and a dark state white point voltage; defining a target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference; and obtaining a white balance look-up table according to the white balance curve to complete a white balance adjustment of the display device.

First claim

What is claimed is:

1 . A white balance adjusting method of a display device, comprising:
measuring a stimulus value of each of gray scales of each of pixels of a panel; defining a white point voltage and a white chromaticity; calculating a white chromaticity difference between a bright state white point voltage and a dark state white point voltage; defining a target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference; and obtaining a white balance look-up table according to the white balance curve to complete a white balance adjustment of the display device.

2 . The white balance adjusting method according to claim 1 , wherein the pixels comprise a red pixel, a green pixel and a blue pixel.

3 . The white balance adjusting method according to claim 2 , before the step of defining the white point voltage and the white chromaticity, further comprising:
calculating the stimulus value to 10 to 12 bits by way of interpolation.

4 . The white balance adjusting method according to claim 3 , wherein the white point voltage is a highest voltage corresponding to a highest value of a transmission rate of the display device; and
the white chromaticity is a red-pixel white chromaticity point, a green-pixel white chromaticity point and a blue-pixel white chromaticity point corresponding to the display device at the highest voltage.

5 . The white balance adjusting method according to claim 2 , wherein the step of defining the target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference comprises:
defining the target white balance curve after setting a chromaticity coordinate turning point according to the white point voltage, the white chromaticity and the white chromaticity difference.

6 . The white balance adjusting method according to claim 5 , after the step of defining the target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference, further comprising:
using a root-mean-square minimum error method to calculate to obtain red pixel, green pixel and blue pixel look-up tables of each of the gray scales corresponding to an adjusted white to serve as an adjusted second white balance pixel look-up table to keep a white brightness gamma value to be equal to 2.2.

7 . The white balance adjusting method according to claim 6 , wherein keeping the white chromaticity gamma value to be equal to 2.2 satisfies formulas of:
1): Y ( R−LUT )+ Y ( G−LUT )+ Y ( B−LUT )=gamma2.2; and 2): Min(( Wx −Wxtar){circumflex over ( )}2+( Wy −Wytar){circumflex over ( )}2);
where Y represents the Y coordinate system of the standard white chromaticity system, R represents the gray scale value of the red pixel at different gray scale voltages, G represents the gray scale value of the green pixel at different gray scale voltages, B represents the gray scale value of the blue pixel at different gray scale voltages, and LUT represents the gray scale value corresponding to each color at different gray scale voltages before adjustment; Wx represents the coordinate value of the white chromaticity X coordinate system, Wy represents the coordinate value of the white brightness Y coordinate system, Wxtar represents the coordinate value of the target white chromaticity X coordinate system, and Wytar represents the coordinate value of the target white chromaticity Y coordinate system.

8 . The white balance adjusting method according to claim 1 , wherein the pixels comprise a red pixel, a green pixel and a blue pixel;
the white balance adjusting method, before the step of defining the white point voltage and the white chromaticity, further comprises: calculating the stimulus value to 10 to 12 bits by way of interpolation; the white point voltage is a highest voltage corresponding to a highest value of a transmission rate of the display device; and the white chromaticity is a red-pixel white chromaticity point, a green-pixel white chromaticity point and a blue-pixel white chromaticity point corresponding to the display device at the highest voltage.

9 . The white balance adjusting method according to claim 1 , wherein the pixels comprise a red pixel, a green pixel and a blue pixel;
the step of defining the target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference comprises: defining a target white balance curve after setting a chromaticity coordinate turning point according to the white point voltage, the white chromaticity and the white chromaticity difference; the white balance adjusting method, after the step of defining the target white balance curve according to the white point voltage, the white chromaticity and the white chromaticity difference, further comprises: using a root-mean-square minimum error method to calculate to obtain red pixel, green pixel and blue pixel look-up tables of each of the gray scales corresponding to an adjusted white to serve as an adjusted second white balance pixel look-up table to keep a white brightness gamma value to be equal to 2.2; and keeping the white chromaticity gamma value to be equal to 2.2 satisfies formulas of:
1): Y ( R−LUT )+ Y ( G−LUT )+ Y ( B−LUT )=gamma2.2; and
2): Min(( Wx −Wxtar){circumflex over ( )}2+( Wy −Wytar){circumflex over ( )}2);

where Y represents the Y coordinate system of the standard white chromaticity system, R represents the gray scale value of the red pixel at different gray scale voltages, G represents the gray scale value of the green pixel at different gray scale voltages, B represents the gray scale value of the blue pixel at different gray scale voltages, and LUT represents the gray scale value corresponding to each color at different gray scale voltages before adjustment; Wx represents the coordinate value of the white chromaticity X coordinate system, Wy represents the coordinate value of the white brightness Y coordinate system, Wxtar represents the coordinate value of the target white chromaticity X coordinate system, and Wytar represents the coordinate value of the target white chromaticity Y coordinate system.

10 . A white balance adjusting method of a display device, comprising:
measuring a stimulus value of each of gray scales of each of pixels of a panel, wherein the pixels comprise a red pixel, a green pixel and a blue pixel; calculating the stimulus value to 10 to 12 bits by way of interpolation; defining a white point voltage and a white chromaticity; calculating a white chromaticity difference between a bright state white point voltage and a dark state white point voltage; defining the target white balance curve after setting a chromaticity coordinate turning point according to the white point voltage, the white chromaticity and the white chromaticity difference; using a root-mean-square minimum error method to calculate to obtain red pixel, green pixel and blue pixel look-up tables of each of the gray scales corresponding to an adjusted white to serve as an adjusted second white balance pixel look-up table to keep a white brightness gamma value to be equal to 2.2; and completing a white balance adjustment of the display device according to the adjusted second white balance pixel look-up table.

11 . The white balance adjusting method according to claim 10 , wherein the white point voltage is a highest voltage corresponding to a highest value of a transmission rate of the display device; and
the white chromaticity is a red-pixel white chromaticity point, a green-pixel white chromaticity point and a blue-pixel white chromaticity point correspondin

Assignees

• Hkc Corp Ltd
• Chongqing Hkc Optoelectronics Tech Co Ltd

Inventors

• Lee Chia-Hang
• Shi jing-ren

Classifications

• G09G3/3607 Primary

  for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels (display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127) · CPC title

• H04N9/73

  Colour balance circuits, e.g. white balance circuits or colour temperature control (camera processing pipelines for colour balance H04N23/88) · CPC title

• H04N9/3182

  Colour adjustment, e.g. white balance, shading or gamut (white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607) · CPC title

• G09G2320/0693

  Calibration of display systems · CPC title

• G09G2320/0673

  for control of gamma adjustment, e.g. selecting another gamma curve · CPC title