Planar Illumination Device With Pseudo Light Sources
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Solution Overview
Problem
Conventional planar illumination devices face challenges in reducing brightness unevenness without increasing the number of light sources or the device thickness, as methods to address this either incur cost increases or fail to meet thickness reduction needs.
Innovation Solution
A planar illumination device with a substrate and a light guide plate, where light sources are arranged two-dimensionally and pseudo light sources are integrated through holes in the light guide plate, allowing light to be reflected and emitted uniformly without increasing the number of light sources or device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large number of light sources are arranged with narrow spacing, then brightness unevenness is suppressed, but the number of light sources increases causing cost increase
Solution Approach 1:
The patent creates pseudo light sources by utilizing through-holes in the light guide plate that do not contain actual light sources. These pseudo light sources mimic the optical effect of real light sources by allowing light to pass through the through-holes and scatter, thereby replicating the illumination pattern without requiring additional physical light source components. This resolves the contradiction by achieving the appearance of many light sources with fewer actual light sources, thus reducing cost while maintaining brightness uniformity.
Solution Approach 2:
The light guide plate acts as an intermediary element between the actual light sources and the observer. By incorporating through-holes in the light guide plate, the patent enables light to be redistributed and scattered in a way that creates the illusion of multiple light sources. The light guide plate mediates the optical path, transforming the illumination pattern from a few bright spots to a more uniform distribution without adding actual light source components.
2Illumination intensity
If the distance between light sources and optical sheet is increased, then brightness unevenness is suppressed, but the thickness of the device increases
Solution Approach 1:
The patent addresses the thickness issue by utilizing the lateral dimension of the light guide plate rather than increasing the vertical distance. By arranging through-holes in specific patterns within the plane of the light guide plate, the patent achieves brightness uniformity through lateral light distribution. This dimensional approach allows the system to maintain a compact thickness while still achieving the desired illumination uniformity that would otherwise require increasing the distance between light sources and the optical sheet.
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 configuration effectively reduces brightness unevenness by utilizing pseudo light sources to mimic the effect of a larger number of light sources with closer spacing, thereby maintaining cost efficiency and reducing device thickness.
Implementation Method 1
The light guide plate has a plurality of through holes being arranged in a thickness direction and individually accommodating the light sources, and a pseudo light source
Data Source
AI summary
A planar illumination device according to embodiments includes a substrate and a light guide plate. The substrate has a plurality of light sources arranged two-dimensionally. The light guide plate is disposed on a side of the surface of the substrate, the surface having the light sources. The light guide plate has a plurality of through holes disposed in a thickness direction and individually accommodating the light sources, and a pseudo light source. The pseudo light source is disposed such that another pseudo light source is not disposed on a line connecting the center of the pseudo light source and the center of one of the light sources.