Light-emitting device manufacturing method with composite wavelength conversion layers
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor light-emitting devices result in reduced light extracting efficiency due to total reflection of light at the interface between the first and second wavelength conversion layers.
Innovation Solution
A method involving a base with a recess, where a light-emitting element is placed, and a first member is partially cured before a second member with higher specific gravity is added, ensuring the second member covers the light-emitting element and inner recess walls without forming an interface between the two members, thereby enhancing light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first wavelength conversion layer and the second wavelength conversion layer are separately cured, then the manufacturing process can be divided into distinct steps, but an interface is formed between the two layers causing total reflection of light and reducing light extracting efficiency
Solution Approach 1:
The patent merges the first and second wavelength conversion layers into a single continuous layer without an interface. By applying the second wavelength conversion material directly over the first wavelength conversion material in a single curing process, the interface that causes total internal reflection is eliminated, thereby improving light extracting efficiency while maintaining manufacturing feasibility
Solution Approach 2:
The patent applies the first wavelength conversion material and allows it to partially set before applying the second wavelength conversion material. This preliminary action enables the first layer to provide structural support while the second layer is applied, ensuring proper layer formation without creating a reflective interface, thus resolving the contradiction between ease of manufacture and light extracting efficiency
2Productivity
If phosphor is concentrated around the light-emitting element to improve light extraction, then light extracting efficiency increases, but color unevenness may occur
Solution Approach 1:
The patent implements local quality by having the first wavelength conversion material with higher concentration near the light-emitting element and the second wavelength conversion material with lower concentration farther away. This gradient distribution optimizes light extraction efficiency near the source while maintaining color uniformity across the entire device surface
Solution Approach 2:
The patent uses a composite wavelength conversion layer comprising two different wavelength conversion materials with different concentrations. The first material (higher concentration) is applied first, then the second material (lower concentration) is applied over it, creating a composite structure that simultaneously achieves high light extraction efficiency and uniform color distribution
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 approach improves light extracting efficiency by preventing light reflection at the interface and allowing for better distribution and concentration of phosphor around the light-emitting element, reducing color unevenness and maintaining high thermal resistance.
Implementation Method 1
dropping a second member into the recess, wherein the second member has a higher specific gravity than the first member
Implementation Method 2
dropping the second member includes semi-curing the first member, and after the second member is dropped, fully curing the first member and the second member
Implementation Method 3
dropping a light reflecting member into the recess, wherein the bottom surface of the recess and a lateral surface of the recess are covered by the light reflecting member
Data Source
AI summary
A light-emitting device having good light extracting efficiency is provided, along with a method for manufacturing the same. A method for manufacturing a light-emitting device includes preparing a base that includes a recess, arranging a light-emitting element on a bottom surface of the recess, dropping a first member into the recess to continuously cover an upper surface of the light-emitting element and an inner wall of the recess by the first member, dropping a second member into the recess, wherein the second member has a higher specific gravity than the first member, and further wherein dropping the second member includes semi-curing the first member, and after the second member is dropped, fully curing the first member and the second member.