LED Wavelength-Converting Structure with Uneven Top Surface
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Solution Overview
Problem
The existing semiconductor light-emitting apparatus, such as white-light LEDs, face issues with reduced light extracting efficiency and shortened lifespan due to weak supporting strength and moisture penetration at the interface between the phosphor plate and the white-light reflective layer, caused by differences in thermal expansion coefficients and incomplete light confinement.
Innovation Solution
A semiconductor light-emitting apparatus is designed with a wavelength-converting structure having an uneven top surface and a white-light reflective layer that includes an additional transparent resin layer without reflective fillers on the outer edge, enhancing supporting strength and preventing light extraction efficiency reduction by utilizing surface tension and capillary phenomena to ensure the transparent resin layer crawls on the uneven surface while keeping reflective fillers from doing so.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the white-light reflective layer is provided to surround the phosphor plate and LED element, then light confinement is improved, but supporting strength is reduced and interface peeling occurs due to weak adhesion
Solution Approach 1:
The white-light reflective layer is divided into two functional parts: (1) a base layer containing reflective fillers for light confinement, and (2) an additional transparent resin layer without reflective fillers that provides enhanced adhesion and support. This segmentation allows each part to perform its specialized function optimally.
Solution Approach 2:
The additional transparent resin layer is selectively formed only on the outer edge portion of the phosphor plate, not on the entire surface. This local application provides enhanced supporting strength where needed (at the edges) while maintaining light extraction efficiency in the central area.
2Loss of energy
If the flat top surface of the reflective layer is positioned below the phosphor plate surface, then light extraction efficiency is maintained, but supporting strength and interface stability are reduced
Solution Approach 1:
The additional transparent resin layer is applied selectively to the outer edge portion of the phosphor plate, creating a localized reinforcement zone. This allows the central area to maintain optimal light extraction while the edges gain enhanced supporting strength.
Solution Approach 2:
The additional transparent resin layer is formed in advance during the manufacturing process, before the device undergoes thermal cycling and moisture exposure. This preliminary reinforcement prevents future interface peeling and stability issues.
3Ease of manufacture
If the interface between phosphor plate and reflective layer is exposed to air, then manufacturing is simplified, but moisture penetration and interface degradation occur over time
Solution Approach 1:
The additional transparent resin layer acts as a protective thin film that seals the interface between the phosphor plate and the reflective layer. This film barrier prevents moisture penetration while maintaining the overall simple structure and manufacturing process.
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 increases the supporting strength of the wavelength-converting structure and maintains high light extracting efficiency while extending the lifespan of the semiconductor light-emitting apparatus by preventing peeling of the reflective layer and moisture penetration.
Implementation Method 1
utilizing surface tension and capillary phenomena to ensure the transparent resin layer crawls on the uneven surface
Implementation Method 2
utilizing surface tension and capillary phenomena to ensure the transparent resin layer crawls on the uneven surface
Data Source
AI summary
A semiconductor light-emitting apparatus is constructed by a substrate; a semiconductor light-emitting element mounted on the substrate; a wavelength-converting structure, provided on the semiconductor light-emitting element, at least an outer edge portion of the wavelength-converting structure having an uneven top surface; and a white-light reflective layer provided on the substrate to surround sidewalls of the semiconductor light-emitting element and the wavelength-converting structure. The white-light reflective layer further includes an additional transparent resin layer excluding the reflective fillers on at least the outer edge portion of the wavelength-converting structure. The additional transparent resin layer is coupled to the transparent resin layer.