Video Display Control Device for Backlight Luminance Adjustment
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Solution Overview
Problem
Conventional methods for dynamically controlling contrast and backlight luminance in displays are ineffective when dealing with videos that have white characters or tickers, as they often result in reduced effectiveness and increased power consumption, especially when the amplitude of the video signal matches the dynamic range.
Innovation Solution
A video display control device that includes a characteristic detecting section, a control data generating section, and a backlight controlling section, which detects the mean luminance of the video signal, generates correction data to redistribute the dynamic range, and adjusts backlight luminance to maintain visual brightness by canceling changes in mean luminance, thereby improving contrast and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dynamic range allocation is performed based on maximum luminance of display, then power consumption is reduced, but contrast improvement effectiveness is lowered when white characters are superimposed
Solution Approach 1:
The patent changes the basis for dynamic range allocation from maximum luminance to mean luminance of the video signal. This parameter change allows the system to adapt to different video content characteristics, maintaining effectiveness when white characters are superimposed while still achieving power consumption reduction through dynamic backlight control.
Solution Approach 2:
The patent implements feedback by continuously detecting the mean luminance of the video signal and using this information to dynamically adjust the dynamic range allocation and backlight luminance. This closed-loop control ensures that contrast improvement remains effective across varying video content while optimizing power consumption.
2Reliability
If dynamic range of high gradation region is allocated to low gradation region, then contrast is improved, but mean luminance of displayed video increases
Solution Approach 1:
The patent applies counterweight by controlling the backlight luminance to compensate for the increase in mean luminance caused by dynamic range allocation. The backlight luminance is reduced in proportion to the mean luminance increase, thereby maintaining constant visual brightness while preserving the contrast improvement benefits.
Solution Approach 2:
The patent changes the control parameter from fixed backlight luminance to dynamically adjusted backlight luminance based on the difference between original and corrected video signal mean luminances. This allows the system to maintain constant visual brightness while enabling dynamic range allocation for contrast improvement.
3Illumination intensity
If backlight luminance is controlled to cancel mean luminance increase, then visual brightness is maintained constant, but power consumption reduction is limited
Solution Approach 1:
The patent applies partial action by allocating only a portion of the dynamic range from the high gradation region to the low gradation region, rather than performing complete dynamic range compression. This partial allocation achieves contrast improvement while limiting the mean luminance increase, thereby enabling moderate power consumption reduction while maintaining visual brightness.
Data Source
AI summary
In a video display control device, a control data generating section allocates a part of a dynamic range of a high gradation region of a video signal to a low gradation region, and a backlight controlling section controls a light emission luminance of a backlight so as to cancel an increase or decrease of a mean luminance of a video displayed on a screen in accordance with an increase or decrease of the mean luminance of a video signal after correction with respect to a mean luminance of the video signal.