Display Signal Processing Device Gamma Correction Circuit
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Solution Overview
Problem
Conventional liquid crystal display devices face challenges in achieving accurate gamma correction for all primary colors, leading to impaired color balance, particularly with blue luminance being significantly deviated towards black, due to the same gamma correction being applied across red, green, and blue colors.
Innovation Solution
A display signal processing device with a reference gradation voltage generating circuit that includes a second predetermined number of variable voltage generating sections, which generate output voltages for gamma correction, connected by resistors to divide difference voltages into a first predetermined number of reference gradation voltages, allowing for selective conversion of display signals to gamma-corrected pixel voltages without significantly increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same gamma correction is applied to all three primary colors (R, G, B), then the gamma correction process is simple, but the color balance is impaired and blue luminance deviates significantly towards black
Solution Approach 1:
The patent applies different gamma correction characteristics to different color channels (R, G, B) by providing separate correction circuits for each color. This allows each color to have its own optimized gamma correction parameters, ensuring accurate color balance while maintaining production feasibility through modular circuit design.
2Ease of manufacture
If a conventional reference gradation voltage generating circuit is used, then the manufacturing cost is low, but accurate gamma correction for all colors cannot be achieved
Solution Approach 1:
The patent segments the gamma correction function into separate correction circuits for each primary color (R, G, B). Each segment can be independently optimized and adjusted, allowing accurate gamma correction for all colors while using cost-effective implementation strategies for each individual circuit segment.
3Manufacturing precision
If ladder resistors are tuned for gamma correction, then some gamma correction is achieved, but it is difficult to make the luminance of the liquid crystal pixel proportional to the gradation value of the display signal
Solution Approach 1:
The patent employs adjustable and tunable correction parameters in each color's gamma correction circuit, allowing dynamic optimization of the correction characteristics. This enables precise control over the relationship between display signal gradation values and actual pixel luminance output, achieving proportionality that fixed resistor networks cannot provide.
Data Source
AI summary
A display signal processing device includes a reference gradation voltage generating circuit that generates ten reference gradation voltages, and a D/A converting circuit that converts a video signal to a pixel voltage by selectively using the ten reference gradation voltages obtained from the reference gradation voltage generating circuit. The reference gradation voltage generating circuit includes four variable voltage generating sections that generate output voltages, which are varied for gamma correction, and nine resistors that are connected to divide difference voltages obtained between output terminals of the four variable voltage generating sections into the ten reference gradation voltages.