Adaptive Backlight Conversion for Local Dimming and Display Visibility
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Solution Overview
Problem
Existing local dimming technologies in liquid crystal display devices face challenges in achieving effective power saving while maintaining display quality, as raising the threshold gray level for backlight emission reduction leads to degraded image visibility and lowering it results in insufficient power savings.
Innovation Solution
A display device with a controller that determines emission amounts for backlight blocks based on gray-level feature values using a conversion function, adjusting this function based on the average emission amounts of backlight blocks and predetermined threshold emission amounts to balance power savings and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the threshold gray level is raised to reduce backlight emission, then power consumption is reduced, but image visibility and display quality are degraded
Solution Approach 1:
The patent applies dynamics by making the conversion function adaptive rather than fixed. The conversion function is dynamically adjusted based on the statistical characteristics of the video frame (such as histogram analysis) to optimize the balance between power saving and display quality. This allows the system to respond to different content types and lighting conditions automatically.
Solution Approach 2:
The patent changes parameters of the conversion function based on video frame statistics. By analyzing the histogram of pixel values and other statistical features, the system modifies the conversion function's parameters (such as threshold values and slope factors) to achieve optimal performance for each specific video content, thereby resolving the contradiction between power saving and image quality.
2Illumination intensity
If the threshold gray level is lowered to maintain display quality, then image visibility is maintained, but power savings are insufficient
Solution Approach 1:
The system dynamically adjusts the conversion function parameters based on real-time analysis of video frame statistics. When video content has low overall brightness or specific histogram characteristics, the conversion function adapts to allow lower threshold gray levels while still achieving adequate power savings through localized backlight control.
Solution Approach 2:
The patent modifies conversion function parameters based on video content analysis. By changing parameters such as threshold values and conversion slopes according to the statistical characteristics of each video frame, the system optimizes the balance between maintaining display quality and achieving power savings for different content types.
3Loss of energy
If local dimming controls backlight emission by region, then power consumption is reduced and contrast ratio is improved, but conversion function complexity increases
Solution Approach 1:
The patent segments the backlight into multiple independently controllable blocks corresponding to different display regions. Each backlight block can be controlled with a separate conversion function that is optimized for the specific content characteristics of its corresponding display region, enabling fine-grained control while managing complexity through modular segmentation.
Solution Approach 2:
The system manages conversion function complexity by adjusting parameters based on video frame statistics. By analyzing the overall content characteristics and applying appropriate conversion function parameters to different backlight blocks, the system achieves effective local dimming without requiring overly complex conversion functions for each individual region.
Data Source
AI summary
A display device includes a backlight including a plurality of backlight blocks, a display panel configured to display an image with light from the backlight, and a controller. The controller is configured to acquire a video frame, determine gray-level feature values to be associated with the plurality of backlight blocks from gray levels of pixels specified in the video frame, determine emission amounts for the plurality of backlight blocks from the gray-level feature values in accordance with a current conversion function, and determine whether to change the current conversion function based on results of comparison of a statistic of the emission amounts of the plurality of backlight blocks with one or more predetermined threshold emission amounts.