Backlight Unit Edge Brightness Uniformity via Asymmetric Light Source Spacing
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Solution Overview
Problem
Direct-illumination type backlight units suffer from non-uniform brightness distribution, leading to visible stains at the edges due to the arrangement of light sources, which is not effectively addressed by existing technologies.
Innovation Solution
The implementation of a backlight unit design featuring a bottom cover with light sources and reflection sheets, where the outermost light sources are spaced differently and the reflection sheets have varying inclined angles, ensuring uniform brightness by adjusting the lengths and angles according to the light source positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the direct-illumination type backlight unit uses a standard arrangement of light sources, then the manufacturing cost is low and brightness is high, but stains become visible at edges due to non-uniform brightness distribution
Solution Approach 1:
The patent applies local quality by making the outermost light sources have different spacing from the sidewall compared to inner light sources. Specifically, the outermost light sources are spaced at a first distance from the sidewall, while inner light sources are spaced at a second distance (different from the first distance). This creates a non-uniform light source arrangement that compensates for edge effects, achieving uniform brightness distribution across the display surface without requiring complex additional components.
2Illumination intensity
If the outermost light sources are spaced equally from the sidewall, then the device structure is simple, but non-uniform brightness and visible stains occur at edges
Solution Approach 1:
The patent employs asymmetry by deliberately creating an asymmetric light source arrangement where outermost light sources are positioned at a different distance from the sidewall compared to inner light sources. This asymmetric positioning compensates for the natural tendency of light to be less uniform at edges, achieving uniform brightness distribution. The asymmetry is carefully designed to balance the light distribution across the entire display surface.
3Illumination intensity
If reflection sheets with uniform inclined angles are used, then the manufacturing process is simple, but uniform brightness cannot be achieved at edges
Solution Approach 1:
The patent applies local quality to the reflection sheets by assigning different inclined angles to different regions. Specifically, reflection sheets associated with outermost light sources have a first inclined angle, while reflection sheets associated with inner light sources have a second inclined angle (different from the first). This regional differentiation in reflection angles optimizes light redirection to achieve uniform brightness distribution across the display surface.
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
This design achieves uniform brightness across the backlight unit, preventing stains from appearing and enhancing the display's overall performance by optimizing light distribution.
Implementation Method 1
The reflection sheet is disposed on an inner surface of the sidewall
Data Source
AI summary
A backlight unit including a bottom cover having a bottom surface and a sidewall extending from the bottom surface, light sources, and a reflection sheet. Outermost ones of the light sources are configured to include a first light source and a second light source. The first light source and the second light source have different distances from the sidewall. The reflection sheet includes a first reflection sheet disposed between the sidewall and the first light source and a second reflection sheet disposed between the sidewall and the second light source. The first reflection sheet and the second reflection sheet have different inclined angles from each other.