Light Guide Plate Inclined Angle Variation for Luminance Uniformity
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Solution Overview
Problem
Conventional surface light source devices face challenges in reducing luminance variation near the light source without compromising the intensity of the light exit pattern, as increasing the maximum inclined angle of the light exit pattern either results in insufficient light scattering or makes the pattern prone to crushing.
Innovation Solution
A surface light source device with a light guide plate featuring light exit patterns that gradually decrease their maximum inclined angle with distance from the light incident surface near the light source, enhancing light scattering for reduced luminance variation while maintaining intensity and preventing pattern crushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the maximum inclined angle of the light exit pattern is increased to enhance light scattering and reduce luminance variation, then the light mixing effect is enhanced, but the aspect ratio of the light exit pattern increases which decreases intensity and makes the pattern prone to crushing
Solution Approach 1:
The patent applies local quality by making the maximum inclined angle of the light exit pattern vary with depth into the light guide plate. Specifically, the inclined angle is set to be smaller in the region near the light incident surface and larger in the region away from it. This spatial variation allows different regions to serve different functions: the region near the light source provides better light scattering to reduce luminance variation, while the region away from the light source maintains higher intensity and resistance to crushing.
2Illumination intensity
If the maximum inclined angle of the light exit pattern is decreased to maintain intensity and prevent crushing, then the light exit pattern is more resistant to damage, but the light scattering effect is insufficient which causes luminance variation near the light source
Solution Approach 1:
The patent resolves this contradiction by implementing spatially varying inclined angles. The region near the light incident surface has a smaller maximum inclined angle which provides sufficient light scattering to reduce luminance variation, while the region away from the light incident surface has a larger maximum inclined angle which maintains high intensity and prevents crushing.
3Ease of manufacture
If a uniform maximum inclined angle is used throughout the light guide plate, then the manufacturing process is simple, but it cannot simultaneously achieve good light scattering near the light source and high intensity away from the light source
Solution Approach 1:
The patent applies parameter changes by making the maximum inclined angle of the light exit pattern vary with depth into the light guide plate. The inclined angle is specifically designed to change from the region near the light incident surface to the region away from it. This parameter variation allows the light guide plate to achieve both good light scattering near the light source and high intensity away from the light source, resolving the limitation of uniform inclined angle designs.
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 reduces luminance variation near the light source while maintaining light intensity and preventing pattern damage, achieving good visual quality by adjusting the maximum inclined angle of the light exit patterns within a range of 25° to 40°.
Implementation Method 1
a light guide plate that guides light emitted from the light source through a light incident surface to output the light emitted to an outside through a light exit surface
Implementation Method 2
the light incident to the light guide plate from the light source 12 is easily scattered in each direction by the light exit pattern 17
Data Source
AI summary
A variation in luminance is reduced near a light source without decreasing intensity of a light exit pattern. A light source is disposed and a light exit pattern is formed. The light exit pattern reflects light guided in a light guide plate and outputs the light. In inclined angles of tangents of the light exit patterns in a section passing through a center axis of the light exit pattern, a largest inclined angle of the tangent is defined as a maximum inclined angle of the light exit pattern. At this time, in the light exit pattern provided in the light guide plate, the maximum inclined angle is decreased with increasing distance from a light incident surface in a region near the light incident surface, and the maximum inclined angle is decreased or kept constant with increasing distance from the light incident surface in a region distant from the region near the light incident surface.