Backlight Signal Processing for LCD Contrast and Cost
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) face challenges in improving image contrast due to increased backlight diffusion, which is exacerbated by the mismatch between the number of backlight areas and pixels, leading to reduced image quality.
Innovation Solution
A backlight signal processing method that generates and processes gray level data signals to create a backlight matrix, allowing for effective control of emitting areas in a display device with a larger number of pixels than emitting areas, thereby enhancing contrast by adjusting brightness and reducing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the number of backlight areas is reduced to lower hardware costs, then manufacturing cost decreases, but backlight diffusion increases and image contrast deteriorates
Solution Approach 1:
The backlight module is divided into multiple emitting areas (first, second, third emitting areas) that can be independently controlled. This segmentation allows the system to use fewer physical backlight regions while maintaining precise local control capability, thereby reducing hardware costs without sacrificing image contrast quality.
Solution Approach 2:
The patent employs gray level data signal processing with coefficient multiplication to dynamically adjust the brightness parameters of each emitting area. By changing the brightness parameters through signal processing rather than increasing physical backlight elements, the system achieves high contrast with reduced hardware complexity.
2Measurement precision
If the number of pixels is increased to improve resolution, then image detail quality improves, but the mismatch with backlight areas increases and control complexity worsens
Solution Approach 1:
Multiple pixel data signals are combined and processed to generate gray level data signals for each backlight emitting area. The control circuit merges information from multiple pixels to determine the appropriate brightness level for each emitting area, thereby managing control complexity while supporting high pixel counts for improved resolution.
Solution Approach 2:
The control circuit acts as an intermediary between the high-resolution pixel array and the reduced number of backlight emitting areas. It processes pixel data signals through gray level conversion and coefficient multiplication to generate appropriate control signals for the emitting areas, bridging the mismatch between pixel count and backlight area count.
3Illumination intensity
If backlight brightness is increased to improve visibility, then image brightness improves, but contrast ratio deteriorates due to diffusion
Solution Approach 1:
Different emitting areas are assigned different brightness levels through independent gray level data signal control. The control circuit can adjust the brightness of each emitting area locally based on the displayed image content, ensuring that brightness is optimized for visibility while maintaining high contrast ratios through localized dimming where needed.
Data Source
AI summary
A backlight signal processing method is suitable for a display device including a backlight module and a LCD panel, wherein the number of multiple emitting areas of the backlight module is smaller than the number of multiple pixels of the LCD panel. The backlight signal processing method includes: generating multiple first gray level data signals according to multiple color data signals; grouping the first gray level data signals to calculate multiple second gray level data signals, wherein the number of the second gray level data signals is smaller than the number of the first gray level data signals; multiplying a coefficient matrix to obtain multiple gray level matrices; performing an overlapping operation on the gray level matrices to obtain a backlight matrix; and controlling the emitting areas to display according to the backlight matrix respectively.