Local Dimming for Arbitrary LCD Shapes Without Boundary Data
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Solution Overview
Problem
Conventional local-dimming algorithms for LCDs with non-rectangular display areas require boundary information, increasing algorithm complexity and making them unsuitable for use in portable consumer-electronics devices, where power efficiency is crucial.
Innovation Solution
A method and apparatus that partition the backlight panel into individually controllable zones to provide local dimming for LCDs with arbitrary-shaped display areas, determining dimming factors based on pixel data and zone area proportions without requiring boundary information, using a two-phase averaging process to compute dimming factors and adjust for luminance non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional local-dimming algorithms are used for non-rectangular display areas, then local dimming can be achieved, but algorithm complexity increases due to boundary information processing
Solution Approach 1:
The patent segments the display area into multiple independently controllable zones without requiring boundary information. Each zone can be individually dimmed based on its own pixel data statistics, eliminating the need for complex boundary processing while maintaining local dimming functionality.
Solution Approach 2:
Each zone performs self-service by independently calculating its own dimming factor based on the statistical characteristics of its pixel data. This eliminates the need for centralized boundary information processing and reduces algorithm complexity while achieving effective local dimming control.
2Illumination intensity
If boundary information is processed to optimize local dimming for non-rectangular displays, then dimming performance is optimized, but processing complexity and power consumption increase
Solution Approach 1:
The patent extracts and removes the boundary information processing step from the local dimming algorithm. By calculating dimming factors directly from pixel data statistics without boundary processing, the method reduces computational power consumption while maintaining effective dimming performance.
3Illumination intensity
If the backlight panel is operated at maximum luminance level over the entire area, then uniform brightness is achieved, but power consumption increases
Solution Approach 1:
The patent applies local quality by allowing different zones of the backlight panel to operate at different luminance levels based on their specific display requirements. Each zone's brightness is independently controlled according to its pixel data characteristics, achieving both brightness uniformity where needed and power savings where not required.
4Use of energy by moving object
If local dimming is implemented with zone-based control, then power savings are achieved, but luminance non-uniformity occurs within zones
Solution Approach 1:
The patent changes the parameter of zone area proportion into account when calculating dimming factors. By considering the proportion of each zone's area that actually displays content, the method compensates for light leakage effects and maintains luminance uniformity across zones while preserving power-saving benefits.
Data Source
AI summary
In a liquid crystal display (LCD), a liquid crystal (LC) panel has a display area of arbitrary shape. A light-emitting area of a backlight panel is partitioned into zones for providing local dimming to the LC panel. The LC panel is partitioned into display regions. An apparatus for controlling the LC panel and the backlight panel has zone registers each recording a proportion of area of a zone covered by a corresponding display region. The apparatus computes a dimming factor for the zone according to its recorded proportion and pixel data of a portion of image located on the zone, allowing local dimming to be provided without requiring boundary information of the display area. A two-phase arrangement is used to calculate the dimming factor, achieving local dimming to save power in backlight generation while reducing a potential loss of image brightness in high-brightness part of the image portion.