Light Guide Plate Inclined Side Faces Brightness Uniformity
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Solution Overview
Problem
Existing surface light source devices using light guide plates often suffer from uneven illumination brightness, particularly around the side face, due to the limited arrangement of secondary guiding portions, which affects the overall display quality of LCD panels and other displaying members.
Innovation Solution
The design incorporates a light guide plate with a slender first guiding portion and multiple secondary guiding portions that are strategically arranged to create a higher density of inner-reflection faces, allowing for improved light guiding and emission uniformity by inclining the first and second side faces to direct light more effectively towards the emission face, thereby increasing brightness and reducing the occurrence of bright lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If secondary guiding portions are sparsely arranged, then device complexity is reduced, but illumination uniformity deteriorates
Solution Approach 1:
The patent applies local quality by varying the density of secondary guiding portions at different locations. Specifically, secondary guiding portions are arranged more densely in regions where light emission needs enhancement and more sparsely where the base structure suffices. This localized variation in guiding portion density optimizes illumination uniformity while controlling overall device complexity.
Solution Approach 2:
The light guide plate is segmented into multiple functional regions with different densities of secondary guiding portions. The first guiding portion is divided into multiple segments by introducing secondary guiding portions at strategic locations, allowing each segment to contribute differently to the overall illumination uniformity while maintaining manageable complexity.
2Illumination intensity
If secondary guiding portions are densely arranged, then illumination uniformity is improved, but device complexity increases
Solution Approach 1:
Instead of uniform dense arrangement throughout, the patent uses local quality to place secondary guiding portions densely only where needed for illumination enhancement, while maintaining sparser arrangement in other regions. This selective density approach achieves illumination uniformity without proportionally increasing overall device complexity.
Solution Approach 2:
The patent applies partial action by introducing secondary guiding portions only at specific critical locations rather than uniformly throughout the entire structure. This partial arrangement provides sufficient illumination uniformity improvement without the excessive complexity that would result from complete dense coverage.
3Ease of manufacture
If side faces are made vertical, then manufacturing is easier, but light guiding efficiency deteriorates
Solution Approach 1:
The patent introduces asymmetry in the side face configuration by making the first side face inclined at a specific angle (smaller than 90° with the extending direction) while the second side face is vertical. This asymmetric design optimizes light guiding efficiency by directing light toward the emission face while maintaining ease of manufacture through the vertical second side face.
Solution Approach 2:
The patent changes the geometric parameter of the first side face from vertical to inclined at a specific angle smaller than 90°. This parameter modification enhances light guiding efficiency by improving light extraction and directionality toward the emission face, while the overall structure remains manufacturable.
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 the brightness and uniformity of illumination on the emission face, resulting in a more observable and high-quality display image for displaying members like LCD panels.
Implementation Method 1
Light from LED 107 disposed opposite to end face 106 of first guiding portion 102 travels within first guiding portion 102 in a direction (length-direction; perpendicular to end face 106) along side face 104 of plate-like member 101
Data Source
AI summary
A surface light source device for illuminating a displaying member of a display comprises a light guide plate and primary light source. Primary light enters into a first guiding portion through an end face (incidence face) thereof extending in an extending direction, then inner-propagating and entering into any second guiding portion gradually meantime. A major part thereof is inner-reflected by an inner-reflection face (first side face) to be directed to a guiding-emitting-portion, then being outputted from an emission face gradually. The first side face makes a sharp angle α with respect to the extending direction at a portion connected to the guiding-emitting-portion. Second guiding portion has a second side face which is located on a side nearer to the incidence face and makes a sharp angle greater than α at a portion connected to the first guiding portion.