Local Dimming Backlight Zoning for Edge Light Source Mismatch
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Solution Overview
Problem
The arrangement of light sources in backlight devices may not match the defined zones for display panels, leading to gaps between light source locations and zone centers, which degrades image quality in local dimming functions.
Innovation Solution
Define zones for display panels such that outmost zones corresponding to outmost light sources are different in size or shape from inner zones, with inner zones located at centers and outmost zones defined as overlapping areas of extended zones, and apply filter coefficients symmetrically with respect to these centers to control luminance levels based on light distribution characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform zones are defined for all light sources, then manufacturing and control are simplified, but image quality degrades due to mismatch between light distribution characteristics and zone boundaries
Solution Approach 1:
The patent applies local quality by defining different zone configurations for different light source positions. Inner light sources use uniform square zones, while outmost light sources use extended zones that overlap into adjacent zones. This local differentiation matches the light distribution characteristics of each position, improving image quality without significantly complicating manufacturing.
Solution Approach 2:
The patent introduces asymmetry by making outmost zones different from inner zones. Specifically, outmost zones are extended in size and overlap with adjacent zones, creating an asymmetric zone structure that compensates for the asymmetric light distribution at edge positions. This asymmetric design resolves the mismatch between uniform zone definitions and non-uniform light patterns.
2Manufacturing precision
If outmost zones are extended to overlap with adjacent zones, then light distribution characteristics are better matched, but zone complexity increases
Solution Approach 1:
The patent segments zones into two types: inner zones for central light sources and outmost zones for edge light sources. This segmentation allows each zone type to be optimized independently for its specific light distribution characteristics, improving image quality while keeping the overall structure manageable through clear categorization.
Solution Approach 2:
The patent merges outmost zones with adjacent zones through overlapping. Instead of creating completely separate zones for each light source, the outmost zones extend and overlap into neighboring zones, effectively combining their coverage areas. This merging approach smooths transitions at boundaries and better matches the physical light distribution without requiring entirely new zone structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves image quality by aligning luminance control with light distribution characteristics, enhancing the effectiveness of local dimming functions despite mismatches in light source and zone arrangements.
Implementation Method 1
Modern backlight devices, such as direct-lit backlights, full-array backlights etc., may be configured to illuminate a display panel with a two-dimensional (2D) array of light sources (e.g., light-emitting diodes (LEDs))
Data Source
AI summary
A display device includes a backlight device, a driver circuit, and a backlight control circuit. The backlight device includes an array of light sources configured to illuminate a display area of a display panel. The display area is segmented into zones corresponding to the light sources, respectively. The zones include inner zones and outmost zones. The inner light sources of the light source array are each located at a center of corresponding one of the inner zones. Each outmost zone is different in shape from at least one inner zone which is adjacent to at least one outmost zone. The backlight control circuit is configured to control a luminance level of a first outmost light source of the array of light sources based on pixel data of pixels in a first outmost zone of the outmost zones, and the first outmost light source corresponds to the first outmost zone.