Light Guide Plate Curved Microstructures for Uniform Illumination
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Solution Overview
Problem
Electrophoretic display devices face issues with uneven brightness due to triangular dark areas and excessive light loss in light source modules, which affect viewing quality across various light environments.
Innovation Solution
Incorporating multiple curved convex optical microstructures on the side surfaces and near the light incident surface of the light guide plate in the light source module, allowing light to be reflected at various angles for even distribution and minimizing light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local high-density pattern bars are disposed at both ends of the light incident surface on the bottom surface of the light guide plate to disperse light and reduce the triangular dark area, then the triangular dark area is reduced, but bright areas appear at the two corners of the light guide plate near the light incident surface
Solution Approach 1:
The patent applies local quality by configuring different optical microstructure types at different locations on the light guide plate. Specifically, first optical microstructures (with first refractive indices) are placed at the bottom surface near the light incident surface, while second optical microstructures (with second refractive indices different from the first) are placed at the top surface. This localized differentiation allows each region to perform its specific function: the bottom microstructures disperse light to reduce dark areas, while the top microstructures control reflection to prevent corner brightness, achieving overall brightness uniformity without excessive corner brightness.
2Illumination intensity
If the left and right sides of the light guide plate are roughly polished to frustrate total internal reflection and reduce the triangular dark area, then the triangular dark area is reduced, but light loss increases excessively (more than 20%)
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive indices of the optical microstructures. The first optical microstructures have a first refractive index, and the second optical microstructures have a second refractive index that is different from the first. By carefully selecting and varying these refractive index parameters, the patent optimizes light reflection and dispersion characteristics. This allows the system to reduce triangular dark areas through controlled reflection while maintaining high light efficiency and avoiding excessive light loss that would occur with rough polishing.
3Adaptability or versatility
If light source bar is disposed beside the light incident surface of the light guide plate to provide illumination, then the electrophoretic display device can maintain viewing quality in various light environments, but triangular dark area and uneven brightness are formed
Solution Approach 1:
The patent applies segmentation by dividing the optical microstructures into two distinct types: first optical microstructures located at the bottom surface near the light incident surface, and second optical microstructures located at the top surface. Each segment performs a specific function in the light control process. The first microstructures handle light dispersion and the second handle reflection control. This segmentation allows the system to maintain viewing quality in various light environments while achieving uniform brightness distribution across the light guide plate.
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 addresses the triangular dark area issue, providing an even surface light source with low light loss and preventing excessive brightness at the corners of the light guide plate, ensuring consistent image quality in diverse lighting conditions.
Implementation Method 1
The light emitted by the light source and scattered to both sides forms a bright area on the light guide plate after total internal reflection by side surfaces of the light guide plate
Data Source
AI summary
A light source module includes a light guide plate and a light source. The light guide plate has a first surface, a second surface, a light incident surface, and two opposite side surfaces. The second surface is opposite to the first surface, and the light incident surface connects the first surface and the second surface. Each side surface connects the first surface and the second surface, and the light incident surface connects the two side surfaces. The light source is disposed beside the light incident surface for emitting an illumination beam toward the light incident surface. The light guide plate includes multiple optical microstructures disposed on each side surface and near the light incident surface. The optical microstructures include multiple curved convex surfaces arranged from one end near the light incident surface to the other end away from the light incident surface. An electrophoretic display device is also provided.