Asymmetrical Directional Conversion Pattern for Light Guide Plate Leakage
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Solution Overview
Problem
Conventional surface light source devices with inclined light guide plates experience significant light leakage due to the directional conversion pattern's symmetrical shape, leading to reduced light use efficiency, especially around the edges where light intensity is lower.
Innovation Solution
The surface light source device incorporates a directional conversion pattern with asymmetrical ridge and valley lines on the light guide plate, where the sum of breadths of inclined surfaces connected to the light source center is greater than those connected to the opposite side, reducing light leakage by minimizing the area prone to leakage and optimizing the angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a directional conversion pattern with symmetrical ridge and valley lines is used on the inclined surface, then the structure is simple and easy to manufacture, but light leakage occurs at the edges where light intensity is lower
Solution Approach 1:
The patent applies asymmetry by configuring the ridge lines and valley lines of the directional conversion pattern such that the sum of breadths of inclined surfaces connected to the light source center is greater than those connected to the opposite side. This asymmetric configuration optimizes light reflection angles to direct light toward the light guide plate main body while minimizing light leakage at edges, resolving the contradiction between manufacturing simplicity and light leakage prevention.
2Length of stationary object
If the light source height is decreased to make the surface light source device thinner, then the device thickness is reduced, but the light source projects above the light guide plate causing light leakage
Solution Approach 1:
The patent applies parameter changes by modifying the configuration parameters of the directional conversion pattern (ridge line and valley line positions and breadths) to create an asymmetric pattern that compensates for the light source projection issue. This allows the system to maintain thin device thickness while preventing light leakage through optimized optical parameters rather than increasing light source height.
3Use of energy by moving object
If a thick light introducing part is provided to accommodate the light source, then light entry efficiency is improved, but the overall device thickness increases
Solution Approach 1:
The patent applies local quality by providing the thick light introducing part only at the light incidence surface where light entry is needed, while keeping the light guide plate main body thin. The asymmetric directional conversion pattern is localized on the inclined surface of the light introducing part to optimize light reflection locally, achieving high light entry efficiency without increasing overall device thickness.
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 significantly reduces light leakage and enhances light use efficiency by ensuring that light is directed more effectively within the light guide plate, improving the overall performance of the surface light source device.
Implementation Method 1
The light entering the light introducing part is reflected from an upper surface or a lower surface of the light introducing part to be guided to the light guide plate main body
Data Source
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AI summary
A light guide plate (33) is provided with a light introduction part (35) with a wedge shape, and a light guide plate main body (34) that is thinner than the maximum thickness of the light introduction part (35) and is provided continuous with the light introduction part (35). A point light source (32) is disposed in a position facing an end surface (light incidence surface (38)) of the light introduction part (35). On a light exit side surface of the light guide plate (33) or a reflective surface for the same is a directivity conversion pattern (36) for converting the directivity spread of light incident to the light introduction part (35) in the direction of the thickness of the light guide plate to directivity characteristics inclined towards a direction parallel with a surface direction of the light guide plate (33). At a part of a cross-sectional surface of the directivity conversion pattern (36) cut parallel to the light incidence surface (38) positioned forward of the point light source (32) and is within the region of the light source width, the lateral width of a sloped surface of a pattern element, a normal line of which is oriented toward a side facing the light source center, is narrower than the lateral width of a sloped surface of the pattern element oriented toward the light source center side or is the same in one part.