LCD Backlight Subarea Control for Contrast Enhancement
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Solution Overview
Problem
Existing liquid crystal display technologies face limitations in improving picture contrast due to the inability of global backlight modulation to accurately reflect brightness details between local image areas, leading to suboptimal display quality.
Innovation Solution
The method involves dividing the liquid crystal display into subareas and using a preset backlight value gain coefficient greater than 1 to enhance the brightness of backlight subareas, allowing for separate control of each subarea's brightness based on image data, thereby improving contrast and peak brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If global backlight modulation is used to control overall brightness, then energy saving is achieved, but picture contrast and local brightness details are insufficient
Solution Approach 1:
The backlight assembly is divided into multiple independently controllable backlight subareas, each corresponding to specific display subareas. This segmentation allows different brightness levels to be applied to different regions, enabling local contrast enhancement while maintaining overall energy efficiency through selective backlight control based on image grayscale values.
Solution Approach 2:
Different backlight subareas are assigned different brightness characteristics based on the local image content. By calculating grayscale values for each display subarea and mapping them to corresponding backlight subareas, the system applies local quality adjustment to enhance picture contrast in specific regions without uniformly increasing overall power consumption.
2Illumination intensity
If backlight brightness is uniformly increased to improve peak brightness, then display contrast improves, but power consumption increases
Solution Approach 1:
The backlight control system dynamically adjusts the brightness of individual backlight subareas based on real-time image grayscale values. This dynamic control allows the system to increase peak brightness only in regions where high brightness is needed, rather than uniformly increasing all backlight subareas, thereby improving contrast while minimizing power consumption.
Solution Approach 2:
The system changes the brightness parameter of specific backlight subareas based on the calculated grayscale values of corresponding display subareas. By mapping grayscale values to backlight brightness levels and applying a gain coefficient, the system selectively enhances peak brightness in high-grayscale regions while maintaining lower brightness in other regions, optimizing the balance between contrast and power consumption.
3Illumination intensity
If subarea backlight control is implemented to improve local contrast, then picture quality improves, but device complexity increases
Solution Approach 1:
The display area is divided into multiple display subareas that correspond to backlight subareas, creating a segmented control structure. This segmentation enables independent control of different regions while maintaining a manageable system architecture where each subarea can be controlled based on local image characteristics without requiring complex global optimization algorithms.
Solution Approach 2:
The system employs feedback by calculating grayscale values from the input image signal for each display subarea and using these values to determine the appropriate backlight brightness level for corresponding backlight subareas. This feedback mechanism enables automatic local contrast enhancement without requiring manual intervention or complex control algorithms, simplifying the overall system while improving picture quality.
Data Source
AI summary
An apparatus for controlling liquid crystal display brightness includes: a subarea image grayscale determining section configured to determine image grayscale values of subarea image data blocks corresponding to backlight subareas according to a received image signal; a subarea backlight value pre-obtaining section configured to pre-obtain subarea backlight values corresponding to the subarea image data blocks according to the image grayscale values of the subarea image data blocks; a subarea backlight value gain section configured to multiply the pre-obtained subarea backlight values with a preset backlight value gain coefficient to obtain gained backlight values of the backlight subareas, wherein the preset backlight value gain coefficient is more than 1; and a subarea backlight value outputting section configured to output the respective gained subarea backlight values to driver circuits of backlight sources in the corresponding backlight subareas to control the brightness of the backlight sources in the corresponding backlight subareas as a result of driving.