Four-Color Panel Overdrive Method for LCD Response Time
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Solution Overview
Problem
Existing overdrive methods for liquid crystal display (LCD) devices with a four-color panel system, such as RGBW or RGBY, face challenges in achieving fast response times and accurate color representation due to the difficulty in satisfying the relational expression W=R+G+B, leading to afterimages and unusual chromatic values, especially when there are large gray-scale differences between adjacent frames.
Innovation Solution
An overdrive method for a four-color panel that calculates R/G/B overdrive target values and a W overdrive target value using specific formulas, incorporating brightness normalized curves and difference calculations to determine optimal gray-scale voltage values, ensuring faster brightness-response time curves and minimizing afterimages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If existing overdrive methods based on RBG three-color display system are applied to four-color panels, then the response time can be reduced, but afterimages and unusual chromatic values occur due to difficulty in satisfying W=R+G+B relationship
Solution Approach 1:
The patent changes the fundamental parameters of the overdrive method by developing separate overdrive algorithms for RGB and W sub-pixels, and by introducing gray-scale conversion formulas that account for the four-color system's unique characteristics. This resolves the contradiction by adapting the overdrive parameters specifically for RGBW panels rather than using generic three-color methods.
Solution Approach 2:
The patent segments the overdrive process into distinct handling of RGB sub-pixels and W sub-pixel, with separate overdrive target value calculations and gray-scale conversion formulas. This segmentation allows each sub-pixel type to be optimized independently, preventing color accuracy issues while maintaining fast response times.
2Speed
If drive voltage is increased to reduce response time, then deflection speed of liquid crystal molecules increases, but power consumption increases and image quality may deteriorate
Solution Approach 1:
The patent implements dynamic overdrive voltage adjustment by calculating optimal overdrive target values based on the relationship between current and target gray-scales. The system dynamically selects voltage levels from lookup tables rather than using fixed high voltages, achieving fast response times while avoiding excessive power consumption and image quality degradation.
3Loss of time
If liquid crystal material viscosity is reduced to improve response time, then deflection speed increases, but light control ability deteriorates and image details become obscure
Solution Approach 1:
Rather than changing the physical properties of the liquid crystal material, the patent changes the electrical drive parameters by developing specific overdrive methods for RGBW panels. This approach achieves fast response times through optimized voltage waveforms and gray-scale conversion without affecting the liquid crystal material's light control properties, thus maintaining image quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces afterimages by optimizing the gray-scale voltage values, allowing for faster response times and accurate color representation, even with large gray-scale differences between frames, thereby improving the display quality of four-color panels.
Implementation Method 1
By applying a drive voltage on the two glass substrates, directions of molecules in the liquid crystal material are controlled and light from the backlight module can thus be reflected to produce images
Data Source
AI summary
An overdrive method of a four-color panel is disclosed. The method comprises searching 10% brightness value point and 90% brightness value point in a normalized curve, calculating difference between R (or B) brightness normalized curve and G brightness normalized curve ranging from 10% brightness value point to 90% brightness value point, and determining each RIG overdrive gray-scale voltage value in an overdrive gray-scale voltage table through evaluating a minimum value of the difference between brightness normalized curves. The obtained changed R/G/B overdrive target values are substituted into a formula for calculating W overdrive target value between different gray-scales.