Light Guide Module Refractive Index Matching
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Solution Overview
Problem
Existing light source modules and display devices face challenges in improving light extraction efficiency and stress management, particularly in thin designs.
Innovation Solution
A light source module comprising a light guide plate with multiple layers of light guide layers and a translucent adhesive layer, where the refractive index difference between layers is minimal, and a storage modulus of the adhesive layer is low, facilitating flexible designs and enhancing light coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a light guide plate with multiple layers and a translucent adhesive layer is used, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The light guide plate is divided into multiple light guide layers (first light guide layer, second light guide layer) with a translucent adhesive layer in between. This segmentation allows each layer to be optimized for specific functions: the first layer for light input and initial distribution, the adhesive layer for bonding and stress management, and the second layer for final light extraction. The segmentation enables improved light extraction efficiency while maintaining manageable complexity through modular design.
Solution Approach 2:
The patent employs composite material structure by combining different materials with specific refractive indices: the first light guide layer material, the second light guide layer material, and the translucent adhesive layer material. Each material is selected to have a refractive index within 0.02 of the others, creating an optically compatible composite structure that minimizes reflection losses at interfaces while maintaining structural integrity and enabling flexible manufacturing.
2Length of stationary object
If the thickness of the light guide plate is reduced for thin design, then device thickness is reduced, but light extraction efficiency deteriorates
Solution Approach 1:
The patent transitions from a single-layer light guide plate to a multi-layer structure with vertical stacking of the first light guide layer, translucent adhesive layer, and second light guide layer. This dimensional change in structure organization allows the system to achieve thin overall profile while maintaining effective light extraction through the layered architecture. The light travels through multiple interfaces in the vertical dimension, compensating for the reduced horizontal thickness.
Solution Approach 2:
By segmenting the light guide plate into multiple thin layers rather than using a single thick layer, the patent achieves the desired thin profile while maintaining light extraction efficiency. Each layer can be optimized for minimal thickness, and the cumulative effect of multiple layers with optimized interfaces provides sufficient light extraction performance without requiring excessive overall thickness.
3Loss of energy
If a translucent adhesive layer is added to bond light guide layers, then light extraction efficiency is improved through refractive index matching, but manufacturing complexity increases
Solution Approach 1:
The translucent adhesive layer is designed with a refractive index that matches both the first light guide layer and the second light guide layer (difference within 0.02). This homogeneity in optical properties across the layered structure eliminates refraction and reflection losses at the interfaces, ensuring efficient light transmission. The optical homogeneity simplifies the manufacturing process by reducing the need for complex interface treatments or additional optical coatings.
Solution Approach 2:
The translucent adhesive layer serves as an intermediary between the first and second light guide layers, providing both mechanical bonding and optical coupling functions. This intermediary layer simplifies manufacturing by enabling direct lamination of the light guide layers without requiring complex alignment or bonding processes, while simultaneously maintaining optimal light extraction through refractive index matching.
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 improves light extraction efficiency, brightness, and reduces stress in flexible display devices by matching refractive indices and using a translucent adhesive layer as a buffer.
Implementation Method 1
The second light guide layer is bonded to the first light guide layer through the translucent adhesive layer
Implementation Method 2
a light guide plate and a light source. The light guide plate includes a first light guide layer, a second light guide layer, and a translucent adhesive layer
Data Source
AI summary
A light source module includes a light guide plate and a light source. The light guide plate includes a first light guide layer, a second light guide layer, and a translucent adhesive layer. The second light guide layer is bonded to the first light guide layer through the translucent adhesive layer. An absolute value of a refractive index difference between the translucent adhesive layer and any one of the first light guide layer and the second light guide layer is less than or equal to 0.02. The light source is disposed adjacent to a side surface of the light guide plate.