Digital Gamma Correction for LCD Gray Scale Precision
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Solution Overview
Problem
Existing liquid crystal display (LCD) devices face difficulties in accurately and easily controlling gamma voltage, which is crucial for achieving precise gray scale levels and image quality, due to the complexity of analog gamma correction methods.
Innovation Solution
A gamma correction device and method that incorporate a gamma voltage controller to generate digital gamma signals and a digital-to-analog converter to produce analog gamma voltages, allowing for precise control and simplification of the driving circuit by integrating these components within the timing controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog gamma correction methods are used, then gamma voltage can be controlled, but the control accuracy is insufficient and the circuit complexity increases
Solution Approach 1:
The patent replaces the analog gamma correction method with a digital gamma correction method. Specifically, it substitutes the analog voltage control mechanism with a digital signal processing approach where digital gamma correction values are generated by a lookup table and converted to analog voltages through a DAC (Digital-to-Analog Converter). This substitution achieves higher control accuracy through digital precision while simplifying the overall circuit architecture by using standard digital components.
Solution Approach 2:
The patent changes the parameter representation from continuous analog voltages to discrete digital values. By using a lookup table that stores digital gamma correction values corresponding to different gray levels, the system achieves precise control through discrete parameter steps. The digital gamma correction values are then converted back to analog form only when needed for the liquid crystal display, maintaining accuracy while simplifying control logic.
2Reliability
If separate gamma voltage generator is used, then gamma voltage can be generated, but the driving circuit becomes complex
Solution Approach 1:
The patent merges the gamma voltage generation function with the existing timing controller or data driver circuitry. Instead of using a separate gamma voltage generator, the digital gamma correction values are generated within the timing controller using a lookup table, and the conversion to analog voltages is performed by a DAC that is integrated into the driving circuit. This merging reduces the number of separate components and simplifies the overall driving circuit architecture while maintaining reliable gamma voltage generation.
3Manufacturing precision
If analog gamma correction is used, then gamma voltage control is possible, but the gray scale precision is insufficient
Solution Approach 1:
The patent substitutes analog voltage adjustment with digital value selection to achieve precise gray scale control. The lookup table stores pre-calculated digital gamma correction values that correspond to exact gray level requirements. This digital approach allows for precise control through software or firmware settings without requiring complex analog adjustment circuits, making the system both precise and easy to operate through digital interfaces.
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
This approach enables easy and accurate control of gamma voltage, improving gray scale precision and simplifying the circuit configuration, thereby enhancing the overall image quality and usability of LCD devices.
Implementation Method 1
a digital-to-analog converter to generate an analog gamma voltage corresponding to the digital gamma signal
Data Source
AI summary
A gamma correction device for use in a display device includes a gamma voltage controller to generate a digital gamma signal in a unit of a predetermined interval, and a gamma voltage generator to generate an analog gamma voltage corresponding to the digital gamma signal.