S-Shaped Light Guide Plate for LED Backlight Uniformity
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Solution Overview
Problem
Liquid crystal display devices using LEDs as light sources face issues with light leakage due to inclined surfaces and non-uniform resin filling when the thickness of the light guide plate is changed in two stages, leading to inefficient light distribution and manufacturing challenges.
Innovation Solution
The implementation of an S-shaped inclined portion on both front and back surfaces of the light guide plate between the light entering and radiation portions, ensuring uniform thickness and preventing light leakage, while allowing for accurate resin filling during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the light guide plate is changed in two stages to accommodate LED thickness, then the LED mounting is enabled, but light leakage occurs from the inclined surface
Solution Approach 1:
The patent applies curvature by forming an S-shaped inclined portion instead of a straight inclined surface. This curved configuration causes light to undergo multiple internal reflections rather than directly escaping, thereby preventing light leakage while maintaining the thickness transition needed for LED mounting.
2Length of moving object
If the thickness of the light guide plate is changed in two stages, then LED mounting is enabled, but resin filling becomes non-uniform
Solution Approach 1:
The S-shaped inclined portion creates a gradual, curved thickness transition rather than an abrupt two-stage change. This curved geometry allows resin to flow uniformly throughout the mold cavity during injection molding, eliminating air traps and ensuring consistent filling across the entire light guide plate thickness.
3Length of moving object
If the thickness of the light guide plate is decreased at the radiation surface, then the display device becomes thinner, but light distribution efficiency deteriorates
Solution Approach 1:
The S-shaped inclined portion optimizes light distribution by creating a gradual curvature that guides light propagation. This curved configuration ensures uniform light emission across the radiation surface while maintaining a thin overall profile, achieving both thickness reduction and efficient light distribution.
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 enhances light distribution by preventing light leakage and ensures uniform resin filling, improving the efficiency and accuracy of the light guide plate's formation and light emission in liquid crystal display devices.
Implementation Method 1
By forming the S-shaped inclined portion which forms the inclined surface on both front and back surfaces thereof between the light entering portion and the light radiation portion of the light guide plate, it is possible to make a pressure necessary for filling a resin at the time of forming the light guide plate uniform. Further, leaking of light from the inclined surfaces can be prevented.
Data Source
AI summary
In a backlight which arranges light emitting diodes on a side surface of a light guide plate, even when the light emitting diodes having a thickness larger than a thickness of the light guide plate are used, it is possible to manufacture the light guide plate with high accuracy by injection molding. In a liquid crystal display device having a backlight which radiates light to a liquid crystal panel, LEDs are mounted on the light guide plate formed on the backlight as a light emitting element, and an S-shaped inclined portion whose thickness is not changed is formed on the light guide plate from a light incident surface to a light emitting surface of the light guide plate. Since the thickness of the inclined portion is not changed, it is possible to make the pressure of resin flow at the time of performing injection molding uniform thus manufacturing the light guide plate with high accuracy.