Display Driver Gamma Adjustment Registers
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Solution Overview
Problem
Existing display drivers have an insufficient range of adjustment for the shoulder portions of the gamma characteristic, making it difficult to achieve accurate color reproducibility across various liquid crystal panels.
Innovation Solution
A display driver with a circuit configuration that includes multiple registers for adjusting the gamma characteristic, such as amplitude, gradient, fine, tap, and partial-voltage-ratio adjustments, allowing for more flexible control of gray scale voltages and voltage ratios, thereby extending the adjustable range of the shoulder portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fine adjustment circuit is used to adjust the shoulder portions of the gamma characteristic, then the gamma characteristic can be adjusted, but the adjustable range is insufficient for various liquid crystal panels
Solution Approach 1:
The gamma characteristic adjustment is divided into multiple independent segments: amplitude adjustment for the overall range, gradient adjustment for intermediate portions, and fine adjustment for shoulder portions. Each segment has its own control circuit and register, allowing independent optimization of each region without interfering with others, thereby extending the total adjustable range while keeping each individual circuit relatively simple.
Solution Approach 2:
The adjustment circuits are designed to be dynamically controllable through register settings, allowing the gamma characteristic to be adapted for different liquid crystal panel types. The control signals can be changed via software/register configuration, providing flexibility and adaptability without requiring hardware changes, thus extending versatility while maintaining circuit simplicity.
2Adaptability or versatility
If multiple adjustment registers are added to extend the adjustable range of gamma characteristic, then the adjustable range is improved, but the device complexity increases
Solution Approach 1:
The multiple adjustment registers and circuits are designed with universal functionality that can handle different adjustment scenarios. The amplitude adjustment circuit, gradient adjustment circuit, and fine adjustment circuit can work independently or in combination, providing a unified solution for various liquid crystal panel types and gamma characteristic requirements, thereby justifying the increased complexity through enhanced versatility.
Solution Approach 2:
The invention changes multiple parameters of the gamma characteristic simultaneously through different adjustment registers (amplitude, gradient, fine adjustment). By allowing independent modification of these parameters, the system achieves comprehensive control over the gamma curve shape and extends the adjustable range to accommodate various panel characteristics, making the increased device complexity worthwhile.
Data Source
AI summary
A liquid crystal display is provided with: a tap adjustment register for adjusting a gray scale level to a gray scale voltage in intermediate portions close to the end portions of the gamma characteristic; and a partial-voltage-ratio adjustment register for adjusting a ratio of a gray scale voltage among a plurality of gray scale levels in the intermediate portions close to the end portions of the gamma characteristic, in addition to an amplitude adjustment register for adjusting an amplitude of a gamma characteristic which determines a relation between gray scale levels and gray scale voltages or brightness levels on a display panel; a gradient adjustment register for adjusting a gradient of intermediate portions of the gamma characteristic while fixing end portions of the gamma characteristic; and a fine adjustment register for finely adjusting the intermediate portions of the gamma characteristic for each gray scale level.