White Balance Adjusting Method for Display Devices
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Solution Overview
Problem
Liquid crystal displays face challenges in maintaining consistent white chromaticity across gray scales due to varying drive voltages, leading to poor color representation and picture quality, particularly in VA-type displays with large chromaticity differences between bright and dark states.
Innovation Solution
A white balance adjusting method that involves measuring stimulus values for each gray scale, calculating white chromaticity differences, and using a root-mean-square minimum error method to create a white balance look-up table, ensuring a gamma value of 2.2 for improved white balance and reducing chromaticity errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different drive voltages are applied to red, green and blue pixels to achieve white chromaticity adjustment, then white chromaticity can be calibrated, but chromaticity drift occurs and coordination continuity at lower gray scales deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing a chromaticity coordinate turning point that dynamically adjusts the white balance curve based on gray scale level. For lower gray scales, the turning point is set at a lower level to maintain coordination continuity, while for higher gray scales, it transitions to a higher level to achieve accurate white chromaticity calibration. This dynamic parameter adjustment resolves the contradiction between chromaticity calibration and coordination stability.
2Measurement precision
If white balance adjustment is performed using conventional methods, then white chromaticity can be maintained at higher gray scales, but chromaticity errors increase and picture quality deteriorates at lower gray scales
Solution Approach 1:
The patent applies local quality by implementing different white balance adjustment strategies for different gray scale regions. A chromaticity coordinate turning point is introduced that operates differently for lower versus higher gray scales. For lower gray scales, the turning point maintains coordination continuity to reduce chromaticity errors, while for higher gray scales, it enables accurate white chromaticity maintenance. This localized approach resolves the contradiction between performance at different gray scale levels.
Data Source
AI summary
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.