White Balance Adjustment for LCD Gamma Voltage Drift
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Solution Overview
Problem
Adjusting GAMMA voltage in LCDs without considering white balance can lead to drifting colors, as the ratios of grayscale voltages for red, green, and blue colors change differently, affecting the display's color accuracy.
Innovation Solution
A white balance adjustment method that involves obtaining initial white balance components for each grayscale of red, green, and blue pixels, fitting relationship curves to adjust these components after GAMMA voltage changes, and creating a new white balance look-up table to maintain balanced color ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GAMMA voltage is adjusted to correct brightness deviation, then grayscale brightness accuracy is improved, but color balance drifts due to different change rates of RGB grayscale voltages
Solution Approach 1:
The patent applies parameter changes by adjusting the GAMMA tie-point voltages to correct grayscale brightness deviation. Specifically, the GAMMA reference voltage generation module modifies the tie-point voltages (V0-V255) to achieve accurate grayscale display while compensating for manufacturing variations in LCD panels.
Solution Approach 2:
The patent introduces a white balance look-up table (LUT) as an intermediary mechanism. The LUT stores pre-calculated correction values for RGB grayscale voltages based on the adjusted GAMMA curve, serving as a mediator that translates the GAMMA voltage adjustment into balanced color output across all grayscale levels.
2Measurement precision
If GAMMA tie-point voltages are adjusted without considering white balance, then grayscale display accuracy is improved, but additional complexity is introduced for color balance correction
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the white balance correction data in a look-up table before actual display operation. The white balance LUT is generated in advance based on the GAMMA curve requirements, allowing the display system to directly reference pre-computed correction values without performing complex real-time calculations.
Solution Approach 2:
The patent uses a look-up table that copies and stores the relationship between grayscale levels and corrected RGB voltage values. Instead of performing complex iterative calculations during operation, the system references pre-stored correction data in the LUT, effectively copying the solution space into a readily accessible format that simplifies the adjustment process.
Data Source
AI summary
The present disclosure relates to a white balance adjustment method and system. The method includes: obtaining initial white balance components of each of grayscales respectively for red pixels, green pixels, and blue pixels; obtaining a first relationship curve by fitting the white balance component of the red pixel with the green pixel, and obtaining a second relationship curve by fitting the white balance component of the blue pixel with the green pixel; calculating the adjusted white balance component of the green pixel after the GAMMA voltage is adjusted; substituting the adjusted white balance component of the green pixel into the first relationship curve and the second relationship curve to respectively obtain the adjusted white balance components of the red pixel and the blue pixel; and creating a second white balance look-up table according to the adjusted white balance components of the red pixels, the green pixels, and blue pixels.