Light Guide Plate Reflecting Grooves for Brightness Uniformity
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Solution Overview
Problem
Existing light emitting modules with light emitting devices disposed on one side of a light guide plate face challenges in minimizing brightness non-uniformities and maintaining a thin profile, as they often suffer from brightness degradation at cell boundaries due to total internal reflection.
Innovation Solution
The light emitting module incorporates a translucent light guide plate with reflecting depressions on the second primary surface and reflecting grooves on the first primary surface, strategically positioned to redirect light and reduce the angle of incidence, thereby suppressing brightness non-uniformities while allowing for a thinner module profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light emitting devices are disposed on one side of a light guide plate, then the module structure is simplified and manufacturing is easier, but brightness non-uniformities occur at cell boundaries due to total internal reflection
Solution Approach 1:
The patent applies local quality by introducing reflecting grooves at specific locations (cell boundaries) rather than uniformly across the entire light guide plate. The grooves are positioned only where brightness non-uniformities occur at the boundaries between adjacent light emitting cell regions, allowing the majority of the light guide plate to remain smooth while locally addressing the brightness uniformity issue at critical boundary areas.
Solution Approach 2:
The patent converts the harmful effect of total internal reflection at cell boundaries into a beneficial effect by using reflecting grooves to redirect light that would otherwise be trapped. The grooves transform the problematic total internal reflection into useful light redirection, causing light to exit the light guide plate at boundary regions and thereby improving brightness uniformity across the display area.
2Length of moving object
If the light guide plate thickness is reduced to achieve a thinner module profile, then the module becomes more compact and aesthetically pleasing, but light extraction efficiency decreases and brightness non-uniformities worsen
Solution Approach 1:
The patent applies local quality by concentrating optical modification features (reflecting grooves) at specific locations (cell boundaries) rather than uniformly across the entire light guide plate. This allows the light guide plate to be made thinner overall while maintaining light extraction efficiency at the critical boundary regions where brightness non-uniformities occur.
Solution Approach 2:
The patent addresses the thickness issue by transitioning from a uniform thickness approach to a dimensionally optimized design where the thickness can be reduced overall, but optical functionality is maintained through surface features (reflecting grooves) that manipulate light paths in a different dimension (at the surface level rather than through bulk 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 effectively suppresses brightness non-uniformities by redirecting light and reducing total internal reflection, enabling a more uniform light emission and allowing for a thinner light emitting module design.
Implementation Method 1
brightness degradation at cell boundaries due to total internal reflection
Implementation Method 2
reflecting depressions on the second primary surface and reflecting grooves on the first primary surface, strategically positioned to redirect light
Data Source
AI summary
A light emitting module have a translucent light guide plate, which has a first primary surface that emits light and an opposite second primary surface, and a plurality of light sources disposed at given intervals on the second primary surface of the light guide plate. The light guide plate is made up of a plurality of light emitting cell regions with a light source disposed in the center section of each of the plurality of light emitting cell regions, an optically functional area is established on the first primary surface in each of the plurality of light emitting cell regions, and each light source is disposed on the second primary surface in a position opposite the corresponding optically functional area. The second primary surface has reflecting depressions at the boundaries between adjacent light-emitting cell regions, and the first primary surface has reflecting grooves positioned away from the center of each cell near the cell boundary.