Liquid Crystal Display Driving Device Minimizing Pseudo-Contours
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Solution Overview
Problem
Conventional liquid crystal display apparatuses experience image degradation due to the generation of moving image pseudo-contours, especially with increased resolution and contrast, which affects the quality of moving images.
Innovation Solution
A driving device for liquid crystal display elements that includes a look-up table unit for inverse gamma correction and linear interpolation, an error diffusion unit, a frame rate control unit, and a sub-frame data conversion unit, which converts input video signal data into sub-frame data using a drive gradation table to minimize pseudo-contours by varying the driving period for each sub-frame and increasing the number of sub-frames in a drive state as gradation increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sub-field method is used to obtain intermediate gradation in digital driving, then the display precision is improved, but moving image pseudo-contours are generated causing image degradation
Solution Approach 1:
The patent applies dynamics by making the sub-field configuration changeable based on image content. The system dynamically selects between different sub-field methods (conventional sub-field method for still images, and alternative methods for moving images) based on detecting image characteristics, thereby adapting the display strategy to minimize pseudo-contours in moving images while maintaining precision in still images.
Solution Approach 2:
The patent changes parameters by modifying the sub-field configuration and light emission timing based on image type. For moving images, it adjusts the sub-field arrangement and light emission center of gravity to reduce pseudo-contour generation, while for still images it uses the conventional configuration optimized for precision display.
2Measurement precision
If conventional sub-field arrangement is used, then still image display quality is improved, but the center of gravity of light emission changes significantly when image data varies causing moving image pseudo-contours
Solution Approach 1:
The system dynamically adjusts the sub-field configuration based on image content detection. When moving images are detected, it switches to an alternative sub-field method that maintains a stable light emission center of gravity, whereas for still images it uses the conventional arrangement optimized for display quality.
Solution Approach 2:
The patent creates alternative sub-field configurations that replicate the functionality of the conventional method for still images while being optimized for moving images. These alternative configurations copy the essential sub-field structure but modify the arrangement to prevent light emission center shifts during image transitions.
3Measurement precision
If resolution and contrast are increased in display apparatuses, then display quality is improved, but moving image pseudo-contours are more prominently generated
Solution Approach 1:
The patent implements a dynamic display system that detects image characteristics and automatically switches between different sub-field methods. For high-resolution and high-contrast moving images, it selects the alternative sub-field method that minimizes pseudo-contour generation, thereby maintaining high display quality without the harmful pseudo-contour effect.
Solution Approach 2:
The system changes display parameters by adjusting the sub-field configuration based on image content. When high-resolution moving images are detected, it modifies the sub-field arrangement and light emission timing to reduce pseudo-contours, while maintaining the high resolution and contrast settings for optimal image quality.
Data Source
AI summary
A look-up table unit converts input video signal data of N bits into (M+F+D) bit data by performing inverse gamma correction and linear interpolation. An error diffusion unit converts the (M+F+D) bit data into (M+F) bit data by error diffusion processing. A frame rate control unit converts the (M+F) bit data into M bit data by frame rate control. A sub-frame data conversion unit, by using a gradation driving table and the M bit data, generates sub-frame data in which all sub-frames include a step-bit pulse respectively, and in which the number of sub-frames to be in a drive state every time the drive gradation increases by one, is increased one by one.