LCD Backlight Zone Control for Peak Brightness and Contrast
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Solution Overview
Problem
Existing liquid crystal display (LCD) technologies face limitations in enhancing display contrast and image quality due to the inability to accurately control backlight brightness, particularly in zoned dynamic backlight modulation, where the maximum peak brightness is constrained, leading to inadequate contrast and hierarchy in images.
Innovation Solution
The method involves determining grayscale values of pixels in zone image data blocks, applying a backlight value gain coefficient when the zone backlight value exceeds a threshold, and using a compensation coefficient when it falls below a second threshold to adjust backlight values and compensate for pixel grayscale values, thereby improving brightness and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dynamic backlight modulation is used to control backlight brightness, then energy saving and display contrast are improved, but the maximum peak brightness is constrained leading to inadequate contrast and hierarchy in images
Solution Approach 1:
The patent applies local quality by dividing the display into multiple backlight zones corresponding to different image brightness regions. Each zone independently controls its backlight brightness based on the local image content, allowing high peak brightness in bright regions while maintaining energy saving in dark regions. This resolves the contradiction by enabling high contrast where needed without sacrificing overall energy efficiency.
Solution Approach 2:
The patent implements dynamics through adaptive backlight control that adjusts in real-time based on image analysis. The system dynamically determines which zones require high backlight brightness and which can be dimmed, creating a flexible, adaptive system that optimizes both peak brightness and energy consumption based on the specific image content being displayed.
2Illumination intensity
If backlight brightness is increased to improve display contrast, then image quality is improved, but energy consumption increases
Solution Approach 1:
The patent segments the backlight system into multiple independently controllable zones. Instead of uniformly increasing backlight brightness across the entire display, only specific zones corresponding to bright image regions receive enhanced backlighting. This segmentation enables selective energy consumption, improving display contrast in critical areas while maintaining lower energy consumption in darker regions.
Solution Approach 2:
The patent applies local quality by tailoring backlight brightness to local image requirements. Each backlight zone adjusts its brightness level according to the corresponding image region's needs, providing high brightness where image content demands it and reducing brightness (and energy consumption) where the image is darker. This resolves the contradiction between display quality and energy efficiency.
3Loss of energy
If zoned dynamic backlight modulation is implemented, then energy saving is improved, but the maximum peak brightness is constrained leading to inadequate contrast
Solution Approach 1:
The patent segments the display into multiple backlight zones that can be independently controlled. This segmentation allows the system to achieve high peak brightness in specific zones where the image content requires it, while maintaining energy saving in other zones. The segmentation enables selective brightness enhancement without compromising overall energy efficiency.
Solution Approach 2:
The patent implements dynamics through adaptive zone-based backlight control. The system dynamically analyzes image content and adjusts backlight brightness on a per-zone basis, enabling high peak brightness in bright regions while keeping darker regions at lower brightness levels. This dynamic adaptation resolves the contradiction by allowing high peak brightness only when and where needed, maintaining energy saving overall.
Data Source
AI summary
An apparatus for controlling liquid crystal display brightness includes: a zone image grayscale determining section configured to determine grayscale values of pixels in a zone image data block under a predetermined rule according to a received image signal; a zone backlight value pre-obtaining section configured to pre-obtain a zone backlight value corresponding to the zone image data block according to the grayscale values; a zone backlight value gain section configured, when it is determined that the zone backlight value is above a first threshold, to multiply the zone backlight value with a backlight value gain coefficient to obtain a backlight value to which a gain is applied, corresponding to the zone image data block, and to output the backlight value to which the gain is applied, to a driver circuit of backlight source in a backlight zone corresponding to the zone image data block, to control brightness of the backlight source in the corresponding backlight zone as a result of driving, where the backlight value gain coefficient is more than 1; and a zone image grayscale compensating section configured, when it is determined that the zone backlight value is below a second threshold, to compensate for the grayscale values of pixels in the zone image data block using compensation coefficients respectively to obtain compensated image data for driving the liquid crystal panel, wherein the compensation coefficient is more than 1.