LCD Backlight Block Control for Object-Based Local Dimming
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Solution Overview
Problem
Existing liquid crystal displays (LCDs) face limitations in local dimming data expression, constrained to 10 bits, which hinders the improvement of contrast ratio and three-dimensional effects, and uniform backlight current application leads to foggy phenomena in high-luminance areas.
Innovation Solution
A display device with a liquid crystal panel and a backlight comprising multiple backlight blocks, controlled by a controller that extracts object areas from an input image, calculates a local dimming gain to enhance luminance, and adjusts current application based on this gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If local dimming data is limited to 10 bits expression range, then device complexity is reduced, but contrast ratio and luminance expression capability deteriorate
Solution Approach 1:
The patent changes the data expression range parameter from 10 bits to 12 bits, enabling grayscale values up to 4095. This parameter change allows for more precise control of backlight intensity and improves contrast ratio without requiring fundamental changes to the display architecture.
2Manufacturing precision
If uniform current is applied to all backlight blocks, then device complexity is reduced, but contrast ratio and three-dimensional effect deteriorate
Solution Approach 1:
The patent applies different current values to different backlight blocks based on local image characteristics. The controller identifies object areas and applies enhanced current to backlight blocks corresponding to these areas, creating local quality variations that improve contrast ratio and three-dimensional effect.
Solution Approach 2:
The patent implements dynamic current control where the current applied to each backlight block varies based on real-time image analysis. The controller continuously adjusts current distribution according to detected object areas and luminance requirements, transforming the static uniform current system into a dynamic adaptive system.
3Illumination intensity
If luminance of object area is increased to improve expressiveness, then object expressiveness is improved, but foggy phenomenon occurs
Solution Approach 1:
The patent changes the luminance parameter by applying a local dimming gain (multiplier greater than 1.0) to object areas. This parameter change increases luminance in specific regions while maintaining control over the overall brightness distribution, preventing excessive luminance increases that cause foggy phenomena.
Solution Approach 2:
The patent applies luminance enhancement selectively to object areas rather than uniformly across the entire display. By identifying object regions and applying localized luminance adjustments, the system improves object expressiveness while avoiding the foggy phenomenon that would result from global luminance increases.
Data Source
AI summary
According to an embodiment of the present disclosure, a display device may comprise a liquid crystal display (LCD) panel, a backlight including a plurality of backlight blocks that provide light to the LCD panel, wherein each of the plurality of backlight blocks includes a plurality of LEDs and a controller configured to extract an object area from an input image, obtain a local dimming gain to increase a luminance of the extracted object area, and control a current applied to backlight blocks mapped to the object area based on the obtained local dimming gain.