Local Dimming Signal Boosting Circuit for LCD Power Reduction
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Solution Overview
Problem
Liquid crystal display (LCD) panels face challenges in maintaining high contrast ratios due to light leakage during low gray level image display, leading to increased power consumption when using local dimming methods to enhance luminance of light source blocks.
Innovation Solution
A method and drive circuit for boosting local dimming signals, where signals are boosted to a reference luminance value when conditions are met and then gradually decreased, with the number of boosting frames counted and reset based on specific conditions, reducing power consumption by adjusting duty and amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming method is used to enhance luminance of light source blocks, then dynamic contrast ratio is improved, but power consumption is increased
Solution Approach 1:
The patent applies periodic action by using intermittent boosting instead of continuous boosting. The boosting drive circuit activates the boosting function only during specific periods when black images are displayed and deactivates it during other periods, thereby reducing overall power consumption while maintaining the luminance enhancement effect when needed
Solution Approach 2:
The patent implements dynamics by making the boosting function adjustable and controllable. The boosting drive circuit can dynamically adjust the boosting status based on display content analysis, switching between boosting and non-boosting states to optimize both contrast ratio and power consumption according to actual display needs
2Illumination intensity
If local dimming signals are boosted to reference luminance value, then dynamic contrast ratio is enhanced, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by analyzing the display content in advance to determine whether boosting is needed. The boosting drive circuit analyzes the image data before rendering and activates boosting only when black images are detected, avoiding unnecessary power consumption from premature or continuous boosting
Solution Approach 2:
The patent implements feedback by continuously monitoring the display content and adjusting the boosting status accordingly. The boosting drive circuit receives local dimming signals, analyzes them to determine black image display, and adjusts the boosting output based on this feedback, creating a closed-loop control system that optimizes power consumption
Data Source
AI summary
There is provided a method of boosting a local dimming signal. In the method, it is determined whether or not local dimming signals, which are applied for individually driving light source blocks per frame, satisfy boosting conditions. Then, a predetermined local dimming signal corresponding to at least one of the light source blocks is boosted to a reference luminance value when the local dimming signals continuously satisfy the boosting conditions, and the boosting luminance of the predetermined local dimming signal at the reference luminance value is gradually decreased after a light adaptation time of an observer's eye. When the luminance of light source blocks that are boosted is gradually decreased before the light adaptation time or luminance of light source blocks that will be boosted is gradually increased to the light adaptation time, power consumption required to boost the light source blocks may be decreased.