Light Guide Plate Cylindrical Hole for Uniform Illumination
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Solution Overview
Problem
Existing planar light source devices using point light sources suffer from uneven brightness and low light usage efficiency due to unreflected light being emitted from the emitting surface adjacent to the point light source, and inefficient light distribution in the light guide plate.
Innovation Solution
A planar light source device with a point light source arranged adjacent to the side surface of a light guide plate, featuring a cylindrical hole at the point light source position that allows unreflected light to be emitted outside and then reused by reflective sheets, improving light distribution and usage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a point light source is arranged at the center of a light guide plate, then light spreads into the light guide plate, but the emitting surface adjacent to the point light source becomes brightened causing brightness difference
Solution Approach 1:
The patent extracts the unreflected light that would otherwise cause brightness non-uniformity by providing a dedicated exit for this light to leave the light guide plate through the hole in the side surface, preventing it from creating bright spots on the emitting surface
Solution Approach 2:
The patent discards the unreflected light through the hole in the side surface and recovers it by using reflective sheets to redirect this discarded light back into the light guide plate, thereby improving overall light usage efficiency while maintaining brightness uniformity
2Illumination intensity
If a substantially semicircular light incident part is formed at the end portion of a side surface, then light enters the light guide plate, but light usage efficiency is lowered due to much light not entering the light guide plate
Solution Approach 1:
The patent performs preliminary action by providing a reflective sheet before light is lost, so that unreflected light exiting through the hole is immediately redirected back into the light guide plate rather than being wasted
Solution Approach 2:
The patent recovers light that would otherwise be lost by capturing the unreflected light through the hole and redirecting it back into the light guide plate using reflective sheets, thereby improving light usage efficiency
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 solution effectively spreads light from the point light source into the light guide plate, enhancing light usage efficiency and achieving uniform luminance with fewer point light sources, contributing to a cost-effective and lightweight design.
Implementation Method 1
the light guide plate has a cylindrical hole that is formed at a position, which corresponds to the position where the point light source is arranged, and wherein the hole forms an opening at the side surface to emit a portion of the light to the outside of the light guide plate, the portion of the light is emitted by the point light source and the portion of the light being a portion that was not totally reflected at the side surface
Data Source
AI summary
A planar light source device including: a point light source; and a light guide plate, wherein the light guide plate includes: an emitting surface; an opposite emitting surface; and a side surface that connects the emitting surface and the opposite emitting surface; wherein the point light source is arranged adjacent to the side surface of the light guide plate, wherein the light guide plate has a cylindrical hole that is formed at a position, which corresponds to the position where the point light source is arranged, and wherein the hole forms an opening at the side surface to emit a portion of the light to the outside of the light guide plate, the portion of the light is emitted by the point light source and the portion of the light being a portion that was not totally reflected at the side surface.