Wavelength Conversion Layer Segmentation for LED Uniformity
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Solution Overview
Problem
Conventional semiconductor light emitting devices face issues with uniform light emission due to non-uniform distribution of fluorescent materials, leading to uneven color and inefficient heat dissipation, which affects light emitting characteristics and efficiency.
Innovation Solution
A method for manufacturing semiconductor light emitting devices involves forming a wavelength conversion layer with a higher concentration of wavelength conversion material on the light emitting element and a lower concentration in a secondary layer, using a two-step process with transparent resin spacers to ensure uniform light emission and efficient heat dissipation by controlling the concentration gradient and light path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fluorescent material is mixed with optically transparent resin and hardened to form wavelength conversion layers, then the resin hardens and takes shape, but the heavier fluorescent particles precipitate by gravity causing non-uniform concentration distribution
Solution Approach 1:
The wavelength conversion layer is divided into multiple layers with different fluorescent material concentrations. The first layer has a higher concentration and the second layer has a lower concentration, creating a gradient structure that prevents uniform precipitation while maintaining overall uniformity. This segmentation allows each layer to compensate for the deficiencies of the others, achieving uniform light emission characteristics.
Solution Approach 2:
Different regions of the wavelength conversion layer are given different fluorescent material concentrations tailored to local requirements. The first layer near the light emitting element has higher concentration for efficient wavelength conversion, while the second layer has lower concentration to prevent over-conversion and maintain color uniformity. This local quality differentiation resolves the contradiction between preventing precipitation and maintaining uniformity.
2Use of energy by moving object
If fluorescent material concentration is increased to improve wavelength conversion efficiency, then heat generation from energy loss increases, but heat dissipation becomes less efficient
Solution Approach 1:
The wavelength conversion function is segmented across multiple layers with varying concentrations. The first layer with higher concentration handles the primary wavelength conversion efficiently, while the second layer with lower concentration provides secondary conversion with reduced heat generation. This segmentation distributes heat generation across layers, improving overall heat dissipation efficiency while maintaining high conversion efficiency.
Solution Approach 2:
The fluorescent material concentration parameter is changed across different layers to optimize both conversion efficiency and heat dissipation. By creating a concentration gradient from the first layer to the second layer, the system achieves high wavelength conversion efficiency in the first layer while the lower concentration in the second layer reduces excessive heat generation, thereby improving heat dissipation efficiency.
3Shape
If surface tension occurs in the optically transparent resin between the cavity and LED chip, then the surface shape of the first resin layer becomes non-uniform, but making the product between optical path length and fluorescent material concentration constant becomes difficult
Solution Approach 1:
The wavelength conversion structure is segmented into multiple layers, where the first layer addresses the surface tension issue directly at the LED chip interface, and the second layer compensates for any non-uniformities. This segmentation allows the first layer to be optimized for heat dissipation and wavelength conversion near the chip, while the second layer ensures uniform optical characteristics across the entire surface, resolving the contradiction between surface uniformity and optical path uniformity.
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 achieves uniform light emitting characteristics with minimal uneven color and efficient heat dissipation, enhancing the light emitting efficiency and reducing temperature-related reductions in performance.
Implementation Method 1
particles of a wavelength conversion material, which acts as a fluorescent material
Implementation Method 2
forming a transparent resin spacer inside the cavity to an extent that slightly exposes an upper surface of the light emitting element
Implementation Method 3
light emitting element that emits light in upward and lateral directions
Data Source
AI summary
A method for manufacturing a semiconductor light emitting device can result in a device that includes a housing having a cavity, a light emitting element on a bottom face of the cavity, and a wavelength conversion layer provided within the cavity. The wavelength conversion layer can include particles of a wavelength conversion material. The method includes forming the wavelength conversion layer within the cavity, which can include applying and hardening a first material to form a first wavelength conversion layer on the light emitting element, and applying and hardening a second material to substantially fill the remainder of the entire cavity, thereby forming a second wavelength conversion layer. The semiconductor light emitting device manufactured by the inventive method can achieve uniform light emitting characteristics without substantially any uneven color and can include high heat dissipation efficiency.