Planar Lighting Device With Four-Sided LED Input
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Solution Overview
Problem
Existing planar lighting devices with light guide plates face challenges in achieving thinner and lighter designs while maintaining uniform illumination, as they require thicker plates to accommodate longer light travel distances, which hinders the enlargement of display screens and increases weight.
Innovation Solution
A planar lighting device with a light guide plate featuring four light entrance planes and inclined rear planes, combined with LED light sources arranged to emit light efficiently, allowing for increased brightness without increasing thickness, and adjustable LED light emission to achieve a bell-curve brightness distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light guide plate thickness is increased to accommodate longer light travel distances, then uniform illumination is achieved, but the device thickness and weight increase
Solution Approach 1:
The patent introduces four light entrance planes positioned at the four sides of the light guide plate, allowing light to enter from multiple lateral directions rather than only from one side. This multi-directional light input enables shorter light travel distances while achieving uniform illumination across the exit plane, thus reducing the required plate thickness without sacrificing illumination uniformity.
Solution Approach 2:
The light guide plate is divided into multiple functional regions with different thicknesses. The plate has a first thickness region near the light entrance planes and a second thickness region away from them, creating a non-uniform thickness distribution. This segmentation allows optimized light propagation paths of different lengths in different regions, enabling uniform illumination with reduced overall thickness.
2Reliability
If the light guide plate thickness is increased to accommodate longer light travel distances, then uniform illumination is achieved, but the device weight increases
Solution Approach 1:
By positioning light entrance planes at four sides rather than requiring thick plates for long light paths, the patent reduces the volume of light guide material needed. This multi-dimensional light input approach achieves uniform illumination with less material, directly reducing device weight.
Solution Approach 2:
The light guide plate has non-uniform thickness distribution with different thickness regions. The plate is thinner in regions where shorter light paths are sufficient and thicker only where needed for proper light propagation. This local quality variation reduces overall material usage and weight while maintaining illumination uniformity.
3Length of stationary object
If the light guide plate thickness is reduced for thinner device design, then device thickness decreases, but uniform illumination cannot be achieved
Solution Approach 1:
The patent compensates for reduced plate thickness by introducing light entrance planes at four sides, allowing light to enter from multiple lateral directions. This multi-dimensional light input provides sufficient light paths even in thinner plates, maintaining illumination uniformity without requiring increased thickness.
Solution Approach 2:
The non-uniform thickness segmentation creates optimized light propagation paths in different regions. By having varying thickness zones, the plate can achieve proper light distribution in thinner overall regions while maintaining uniform illumination characteristics.
4Weight of stationary object
If the light guide plate thickness is reduced for thinner device design, then device weight decreases, but uniform illumination cannot be achieved
Solution Approach 1:
The multi-directional light input from four sides enables effective light propagation in thinner plates, reducing the volume and weight of light guide material needed while maintaining uniform illumination. The patent achieves weight reduction without sacrificing illumination quality.
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 enables a higher brightness emission with reduced thickness and weight, suitable for larger display screens, and adjustable illuminance distribution for uniform lighting, enhancing the performance of liquid crystal display devices.
Implementation Method 1
a light guide plate for admitting light emitted by the light sources and emitting the light through the light exit plane thereof
Implementation Method 2
light emitted by the light sources and admitted into the light guide plate is guided in given directions
Data Source
AI summary
The absolute value of the light amount is increased by providing main light sources and auxiliary light sources on four sides of a light guide plate having a flat and rectangular light exit plane whereas the amounts of light emitted by LED chips of the main light sources and the auxiliary light sources are adjusted such that illuminance is highest near the central area of the light guide plate to obtain a high-in-the-middle, bell-curve illuminance distribution for light emitted by the light guide plate. A planar lighting device achieving a reduced thickness and weight and capable of emitting an increased amount of illumination light is provided.