Planar Illumination Reflector Asymmetry for Uniform Luminance
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Solution Overview
Problem
Existing planar illumination devices exhibit non-uniform luminance at the emission surface, with lower luminance at the outer peripheral part compared to the inner side, affecting the overall lighting uniformity.
Innovation Solution
The planar illumination device incorporates a reflector with asymmetric reflection surfaces at the outer peripheral part segments, featuring larger intersection angles with respect to the substrate, to redirect light more steeply towards the emission surface, enhancing luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a curved reflector plate is used to improve light utilization efficiency, then light utilization efficiency is improved, but luminance uniformity at the emission surface deteriorates due to lower luminance at the outer peripheral part
Solution Approach 1:
The reflector is divided into multiple segments with different reflection characteristics. The outer peripheral part has a larger intersection angle to redirect light more steeply, while inner segments have smaller angles. This local differentiation of reflection properties ensures that each segment contributes appropriately to achieving uniform luminance across the emission surface while maintaining high light utilization efficiency.
Solution Approach 2:
The reflector segments are designed with asymmetric intersection angles relative to the substrate. Specifically, the outer peripheral segments have larger intersection angles compared to inner segments, creating an asymmetric configuration that compensates for the natural light distribution pattern and achieves uniform luminance output across the emission surface.
2Use of energy by moving object
If the reflector is formed in a curved shape to improve light utilization, then light utilization efficiency is improved, but the device complexity increases
Solution Approach 1:
The curved reflector is segmented into multiple discrete sections, each with a specific intersection angle. This segmentation allows the complex curved shape to be constructed from simpler modular elements, making manufacturing more feasible while maintaining the light-redistributing functionality that improves light utilization efficiency.
Solution Approach 2:
Different segments of the reflector have locally optimized intersection angles tailored to their specific positions. The outer peripheral segments have larger angles while inner segments have smaller angles, allowing each local region to contribute optimally to light utilization without requiring an overly complex overall structure.
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
The asymmetric reflection surfaces improve luminance uniformity across the emission surface, particularly when using light sources with batwing light distribution, reducing thickness and enhancing local dimming contrast.
Implementation Method 1
a reflector disposed at the one surface side of the substrate and including a plurality of segments, each segment of the plurality of segments being corresponding to a respective light source of the plurality of light sources
Data Source
AI summary
The planar illumination device includes a substrate including a plurality of light sources provided at one surface side, and a reflector disposed at the one surface side of the substrate and including a plurality of segments corresponding to the plurality of light sources, respectively, each of the segments being formed with a reflection surface surrounding each of the light sources. In an outer peripheral part segment disposed at an outer peripheral part of the reflector out of the plurality of segments, the reflection surface at an outer side and the reflection surface at an inner side are asymmetric.