Programmable Dithering for LCD Video Displays
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Solution Overview
Problem
Liquid crystal displays (LCDs) with fixed color palettes face issues with color depth and screen flicker due to interactions between pixel inversion and dither patterns, leading to visible artifacts like banding and flicker.
Innovation Solution
A programmable method and system that harmonizes pixel inversion and dither patterns by determining a cooperating dither pattern to interact with the pixel inversion pattern, reducing or eliminating visual artifacts through a programmable dither block and processor in the LCD driver circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed dither pattern is used for LCD displays, then color depth is improved through dithering, but visible artifacts such as banding and flicker occur due to interaction with pixel inversion patterns
Solution Approach 1:
The patent applies dynamics by making the dither pattern programmable and adaptable rather than fixed. The system can dynamically select and adjust dither patterns based on the specific pixel inversion pattern being used, allowing the dithering process to adapt to different display conditions and minimize artifacts while maintaining color depth.
Solution Approach 2:
The patent changes the parameters of the dither pattern itself, allowing different patterns to be selected and applied. By modifying the dither pattern parameters to harmonize with the pixel inversion pattern, the system resolves the interaction that causes banding and flicker artifacts while preserving the color depth benefits of dithering.
2Measurement precision
If dithering is applied to LCDs with limited color palettes, then the illusion of color depth is created, but the interaction with pixel inversion patterns causes screen flicker
Solution Approach 1:
The patent modifies the dither pattern parameters to be compatible with the pixel inversion pattern. By selecting and applying appropriate dither patterns that harmonize with the inversion scheme, the system maintains the perceived color depth while eliminating the flicker effect that arises from the interaction between fixed dither patterns and pixel inversion.
Solution Approach 2:
The patent uses multiple dither patterns that can be selected and applied based on the specific display conditions. By having a library of dither patterns and selecting the appropriate one that matches the pixel inversion pattern, the system achieves harmonious interaction that prevents flicker while maintaining color depth perception.
3Reliability
If a fixed pixel inversion pattern is used to prevent liquid crystal degradation, then AC drive is achieved, but interaction with dither patterns creates visible banding
Solution Approach 1:
The patent makes the dithering process dynamic by allowing selection of different dither patterns based on the pixel inversion pattern being used. This adaptability enables the system to maintain the reliability benefits of AC drive through pixel inversion while eliminating banding artifacts by using dither patterns that harmonize with the specific inversion scheme.
Solution Approach 2:
The patent changes the dither pattern parameters to match the pixel inversion pattern characteristics. By selecting dither patterns with appropriate properties that are compatible with the inversion scheme, the system preserves liquid crystal protection while preventing the formation of visible banding artifacts.
Data Source
AI summary
In a liquid crystal display (LCD) driver circuit, harmonizing a pixel inversion pattern and a dither pattern is disclosed. The pixel inversion pattern and the cooperating dither pattern interact with each other in such a way that there is substantially no discernable video artifacts generated. The cooperating dither pattern can be selected from a plurality of dither patterns using a programmable dither block.