Gamma Curve Compensation Circuit for Display Color Shift
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Solution Overview
Problem
Liquid crystal display panels experience color shift due to non-linear relationships between driving voltage and light transmittance, caused by differences in frame rates and color-resist materials, leading to deteriorated display quality.
Innovation Solution
A gamma curve compensation circuit and method that adjusts data voltages provided to data lines based on frame rate and pixel color, using variable resistances and rectifying circuits controlled by a compensation control circuit to maintain optimal gamma curve characteristics, thereby preventing color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data voltage is adjusted according to a fixed gamma curve, then the relationship between gray-level image data and pixel brightness is maintained, but color shift occurs due to current leakage changes caused by different frame rates and color-resist materials
Solution Approach 1:
The patent applies dynamics by making the gamma curve adjustable based on operating conditions. Specifically, the system dynamically selects between first and second gamma curves according to the frame rate, and further adjusts using compensation voltages based on pixel color. This transforms a static gamma curve into a dynamic one that adapts to different frame rates (60Hz/120Hz) and color requirements, resolving the contradiction between maintaining gamma accuracy and ensuring display consistency across varying conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the gamma curve parameters according to frame rate and color. The system changes the gamma curve selection (first or second curve) based on frame rate detection, and further adjusts voltage parameters using color-specific compensation voltages. This parameter adaptation allows the system to maintain accurate gamma characteristics while compensating for frame rate-induced current leakage variations, thereby eliminating color shift.
2Speed
If frame rate is increased to improve display responsiveness, then speed is improved, but current leakage of pixel changes causing gamma curve shift and color shift
Solution Approach 1:
The system dynamically adapts to different frame rates by detecting the current frame rate and selecting the appropriate gamma curve. When frame rate changes from 60Hz to 120Hz, the system switches between pre-calibrated gamma curves and applies compensation voltages, allowing high-speed operation without gamma curve degradation or color shift.
Solution Approach 2:
The system incorporates feedback mechanisms by detecting the actual frame rate being used and adjusting the gamma curve selection and compensation voltages accordingly. This closed-loop approach ensures that regardless of whether the display operates at higher or lower frame rates, the gamma characteristics remain stable and color accuracy is maintained.
3Manufacturing precision
If gamma curve compensation is performed for all pixels uniformly, then gamma curve accuracy is improved, but device complexity increases due to need for color-specific compensation
Solution Approach 1:
The patent applies local quality by implementing color-specific gamma curve compensation. Different compensation voltages are applied to pixels of different colors (RGB) based on their respective current leakage characteristics. This localized approach targets the specific color that requires compensation, rather than applying uniform compensation to all pixels, thereby improving gamma accuracy while managing complexity through selective adjustment.
Data Source
AI summary
A display apparatus and a gamma curve compensation circuit and a driving method thereof are provided. Control the gamma curve compensation circuit to adjust data voltages provided to data lines according to a frame rate of the display apparatus, so as to perform gamma curve compensation and improve display quality of the display apparatus.