Anisotropic Conductive Adhesive Light Extraction
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Solution Overview
Problem
In light emitting devices using semiconductor elements, the absorption of light by conductive particles in anisotropic conductive adhesives leads to reduced light extracting efficiency due to uneven distribution and high concentration of conductive particles, particularly in small-size elements where short circuits can occur.
Innovation Solution
The anisotropic conductive adhesive has a varying concentration of electrically conductive particles, with a higher concentration in the lower region for electrical continuity and a lower concentration in the surrounding region to minimize light absorption, achieved by applying a magnetic field to draw particles closer to the base body before hardening, ensuring efficient light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anisotropic conductive adhesive with high concentration of electrically conductive particles is used to ensure electrical continuity, then electrical conductivity is improved, but light absorption increases and light extracting efficiency deteriorates
Solution Approach 1:
The patent applies different concentrations of electrically conductive particles in different regions of the anisotropic conductive adhesive. The lower region (near the base body) has a higher concentration to ensure electrical continuity, while the upper region (surrounding the semiconductor light emitting element) has a lower concentration to minimize light absorption. This spatial variation in particle concentration resolves the contradiction between electrical conductivity and light transmission.
2Reliability
If electrically conductive particles are uniformly dispersed in anisotropic conductive adhesive, then uniform electrical conductivity is achieved, but light absorption by particles in surrounding regions increases
Solution Approach 1:
The patent creates a non-uniform distribution of electrically conductive particles within the anisotropic conductive adhesive. By concentrating particles in the lower region and reducing their presence in the upper surrounding region, the invention achieves both sufficient electrical conductivity where needed and minimized light absorption where light transmission is critical.
3Strength
If anisotropic conductive adhesive is disposed with larger area than semiconductor light emitting element to fix the element, then bonding strength is improved, but more electrically conductive particles are present in surrounding regions causing increased light absorption
Solution Approach 1:
The patent maintains a large-area anisotropic conductive adhesive configuration for sufficient bonding strength, but implements regional differentiation in particle concentration. The lower region provides strong electrical connection and bonding, while the upper region with reduced particle concentration allows light to pass through the surrounding areas without significant absorption.
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 reduces light absorption, enhances light extracting efficiency, and maintains electrical continuity, resulting in improved performance and reliability of light emitting devices.
Implementation Method 1
achieved by applying a magnetic field to draw particles closer to the base body before hardening
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~3A
AI summary
A light-emitting device (100) having superior light extraction efficiency and method for producing a light emitting device are provided. A light emitting device (100) includes a base body (20) having wiring conductors (22), conductive adhesive member (30), especially an anisotropic conductive adhesive member (30), including electrically conductive particles (31) mixed in a light transmissive resin (32), and a semiconductor light emitting element (10) bonded on the wiring conductors (22) via the anisotropic conductive adhesive (30). The anisotropic conductive adhesive member (30) includes the electrically conductive particles (31) with a concentration lower in a surrounding region around the semiconductor light emitting element (10) than in a lower region located between the semiconductor light emitting element (10) and the base body (20).