Semiconductor Light-Emitting Device Wavelength Conversion Heat Dissipation
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Solution Overview
Problem
Existing semiconductor light-emitting devices face challenges in achieving uniform wavelength conversion and efficient heat dissipation due to the use of wavelength-converted materials, which often require thick adhesive layers that reduce efficiency and cause chromaticity issues.
Innovation Solution
A semiconductor light-emitting device with a wavelength conversion structure attached to a semiconductor light-emitting stack using a first attaching layer, where the structure includes a reflective or transparent conductive layer between the opaque substrate and the stack, allowing for improved heat dissipation and reduced adhesive material absorption, enabling better wavelength conversion efficiency and color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wavelength-converted material totally covers the LED chip to increase wavelength-converting efficiency, then the wavelength conversion efficiency is improved, but the heat dissipation performance deteriorates
Solution Approach 1:
The patent divides the wavelength conversion structure into multiple segments: a first wavelength conversion layer covering the light-emitting region, and a second wavelength conversion layer covering the side surface. This segmentation allows different regions to perform wavelength conversion while the exposed substrate surface maintains heat dissipation capability, resolving the contradiction between coverage efficiency and thermal management.
Solution Approach 2:
The patent applies wavelength conversion material selectively to specific regions rather than uniformly across the entire chip. The first wavelength conversion layer is applied to the top surface where light emission occurs, while the second layer covers the side surface. This local application ensures efficient wavelength conversion at the emission region while leaving the substrate surface exposed for heat dissipation.
2Ease of manufacture
If adhesive material is used to form the wavelength-converted material structure, then the manufacturing process is simplified, but light absorption increases and wavelength-converting efficiency deteriorates
Solution Approach 1:
The patent extracts and removes the adhesive material from the wavelength conversion structure. Instead of using adhesive to bind the wavelength conversion material to the substrate, the invention uses a reflective layer and direct deposition methods. This elimination of adhesive material prevents light absorption by the adhesive, thereby maintaining high wavelength conversion efficiency while still achieving secure attachment through the reflective layer interface.
Solution Approach 2:
The patent introduces a reflective layer as an intermediary between the substrate and the wavelength conversion structure. This reflective layer serves multiple functions: it provides a bonding interface without requiring adhesive material, it reflects unconverted light back into the conversion layer to improve efficiency, and it maintains structural integrity without introducing light-absorbing adhesive materials.
3Use of energy by moving object
If thicker wavelength-converted material is used to receive more light, then the light absorption is improved, but the chromaticity uniformity deteriorates
Solution Approach 1:
The patent segments the wavelength conversion function across two distinct layers with different thicknesses and positions. The first layer on the top surface has optimized thickness for receiving light from above, while the second layer on the side surface provides additional conversion for side-emitting light. This segmentation allows each layer to be independently optimized for its specific function, achieving uniform chromaticity without requiring excessive thickness that would cause non-uniformity.
Solution Approach 2:
The patent applies different thicknesses of wavelength conversion material to different locations based on local light emission characteristics. The first wavelength conversion layer is applied to the top surface where omnidirectional light emits, while the second layer is applied to the side surface where side-emitting light exits. This local optimization ensures that each region has sufficient material thickness to absorb its specific light emission, achieving uniform chromaticity across the entire device without requiring uniformly thick material throughout.
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 enhances wavelength conversion efficiency and color rendering by simplifying the encapsulation process, controlling the thickness and quality of the wavelength conversion structure, and promoting heat dissipation, thereby improving the overall performance of the semiconductor light-emitting device.
Implementation Method 1
The wavelength conversion structure receives the primary light from the semiconductor light-emitting stack and then generates a converted light whose wavelength is different from that of the primary light
Implementation Method 2
In addition, there is at least a reflective layer or a transparent conductive layer in-between the opaque substrate and the semiconductor light-emitting stack
Data Source
AI summary
The present invention discloses a semiconductor light-emitting device including a semiconductor light-emitting element, a first attaching layer and a wavelength conversion structure. The primary light emitted from the semiconductor light-emitting element enters the wavelength conversion structure to generate a converted light, whose wavelength is different form that of the primary light. In addition, the present invention also provides the method for forming the same.