LCD Brightness Control via Area Segmentation
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) face issues with deteriorated concentration and contrast ratio when both image and blank areas are displayed on the same screen, as the brightness levels of both areas are adjusted simultaneously, leading to increased brightness of the blank area, which affects image clarity.
Innovation Solution
A liquid crystal display system that adjusts brightness levels in each division area by calculating the average and dispersion of gray levels of image data, dividing the panel into separate areas for image and blank regions, and using a timing controller to supply specific brightness variable signals to the backlight unit, allowing independent adjustment of brightness levels for each area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the brightness level of the backlight is adjusted based on the average gray level of the entire screen, then the overall power consumption is reduced and the display adapts to different image conditions, but the brightness of the blank area increases when a bright image is displayed, which deteriorates the concentration and contrast ratio of the image area
Solution Approach 1:
The patent divides the display screen into multiple regions (image area and blank area) and calculates the average gray level separately for each region. This allows independent brightness control for each area, preventing the blank area from becoming overly bright while maintaining power savings in the image area. The segmentation enables the system to apply different brightness adjustment strategies to different parts of the display.
Solution Approach 2:
The patent applies different brightness control characteristics to different regions of the screen. The image area uses one brightness adjustment strategy while the blank area uses another, allowing each region to have optimized local quality. This ensures that the blank area does not interfere with image concentration while the image area maintains appropriate brightness for visibility.
2Device complexity
If the brightness level is simultaneously adjusted for both image area and blank area, then the control system is simple and uniform, but the image concentration and contrast ratio are deteriorated due to increased brightness of the blank area
Solution Approach 1:
The patent segments the control system into separate control paths for the image area and blank area. Each area has its own average gray level calculation and brightness adjustment mechanism. This segmentation increases control precision for each area while maintaining reasonable system complexity through modular design.
Solution Approach 2:
The patent implements local quality control by applying different brightness adjustment characteristics to different regions. The image area receives brightness control optimized for image visibility, while the blank area receives control optimized for maintaining contrast. This local differentiation improves image concentration and contrast ratio without excessive complexity.
3Illumination intensity
If the brightness level of the backlight is highly adjusted when a bright image is input, then the image area achieves good visibility and brightness, but the blank area also becomes overly bright, reducing the contrast and concentration of the displayed image
Solution Approach 1:
The patent segments the brightness control into separate channels for image area and blank area. When a bright image is detected in the image area, the system increases brightness only for that region while maintaining lower brightness for the blank area. This segmentation allows the image area to achieve good visibility without compromising the contrast ratio.
Solution Approach 2:
The patent applies local quality control by optimizing brightness characteristics for each region independently. The image area receives enhanced brightness when needed for visibility, while the blank area maintains characteristics that preserve contrast. This local optimization resolves the contradiction between image brightness and contrast ratio.
Data Source
AI summary
A liquid crystal display and a driving method thereof are provided. The liquid crystal display comprises a liquid crystal panel; a gate driver; a data driver; a timing controller supplying a control signal of the gate driver and a control signal of the data driver and supplying a brightness variable signal depending on an average of gray levels of image data; and a backlight unit adjusting a brightness level of the lamp in response to a plurality of brightness variable signals, wherein the timing controller divides the liquid crystal panel into a first division area, which displays image data, equal to or smaller than an average of reference gray levels and dispersion of reference gray levels and a second division area comprising areas other than the first division area by calculating an average and dispersion of gray levels of the image data with a line unit, and supplies a first brightness variable signal adjusting a brightness level of the first division area and a second brightness variable signal adjusting a brightness level of the second division area.