Multi-Layer Wavelength Converter LED for Heat Dissipation
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Solution Overview
Problem
There is a need for a light emitting element with improved luminous efficacy and heat dissipation efficiency, particularly for high-power applications, which can emit white light with specific color temperature and is suitable for chip scale packages without separate housing.
Innovation Solution
A light emitting element with a plurality of wavelength converters, including a light emitting structure with conductive semiconductor layers, contact electrodes, insulating layers, bulk electrodes, and wavelength converters that cover the light emitting structure and are separated by a translucent layer, enabling efficient wavelength conversion and heat dissipation, and a method of manufacturing this element at the wafer level to ensure uniform optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single thick wavelength converter layer is used, then the device structure is simpler, but the luminous efficacy is reduced due to increased light absorption and heat generation
Solution Approach 1:
The single thick wavelength converter layer is divided into multiple thinner layers (first wavelength converter layer, second wavelength converter layer, and third wavelength converter layer) with different phosphor compositions. This segmentation reduces light absorption losses within each layer while maintaining overall wavelength conversion efficiency, thereby improving luminous efficacy without significantly increasing device complexity.
Solution Approach 2:
Each wavelength converter layer is assigned specific phosphor materials optimized for particular wavelength conversion tasks. The first layer converts blue light to green, the second layer converts blue light to yellow, and the third layer converts blue light to red. This local optimization of material properties at different positions enables efficient wavelength conversion across the visible spectrum while minimizing energy losses.
2Loss of energy
If multiple wavelength converter layers are added to improve luminous efficacy, then the energy conversion efficiency increases, but the device structure becomes more complex
Solution Approach 1:
Multiple wavelength converter layers with different phosphor materials are combined in a stacked configuration, where each layer performs specific wavelength conversion functions. The first layer contains green phosphors, the second layer contains yellow phosphors, and the third layer contains red phosphors. This merging of functional layers achieves comprehensive wavelength conversion while maintaining a relatively integrated structure that does not excessively increase device complexity.
3Illumination intensity
If the wavelength converter layer is made thicker to improve color rendering, then the white light quality improves, but the heat dissipation efficiency deteriorates
Solution Approach 1:
The thick wavelength converter layer is segmented into multiple thinner layers, each optimized for specific phosphor materials. This segmentation allows better heat distribution and dissipation across the layered structure while maintaining sufficient total thickness for effective wavelength conversion and high-quality white light emission. The distributed architecture reduces localized heat accumulation compared to a single thick layer.
4Manufacturing precision
If wafer-level manufacturing is used to ensure uniform optical characteristics, then the manufacturing precision improves, but the production process becomes more complex
Solution Approach 1:
Multiple wavelength converter layers with different phosphor materials are formed simultaneously on the entire wafer surface before wafer dicing into individual devices. This preliminary formation of all necessary layers across the full wafer area ensures uniform optical characteristics across all resulting devices while enabling efficient batch production. The simultaneous formation process reduces the number of separate manufacturing steps needed for each individual device.
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 provides a light emitting element with enhanced luminous efficacy, mechanical stability, and heat dissipation efficiency, emitting white light with consistent color temperature and reduced deviation in optical characteristics, suitable for high-power applications and chip scale packages.
Implementation Method 1
a light emitting structure including a first conductive type semiconductor layer, a second conductive type semiconductor layer, and an active layer interposed between the first conductive type semiconductor layer and the second conductive type semiconductor layer
Implementation Method 2
a first wavelength converter covering at least part of a side surface and an upper surface of the light emitting structure; a translucent layer disposed on the first wavelength converter; and a second wavelength converter disposed on the translucent layer
Data Source
AI summary
Disclosed are a light-emitting element and a production method therefor. In one aspect, a light-emitting element is provided to comprise a light-emitting structure comprising a first and second semiconductor layers and an active layer; a first and second contact electrodes respectively making ohmic contact with the first and second semiconductor layers; an insulating layer for insulating the first contact electrode and second contact electrode; a first and second bulk electrodes respectively electrically linked to the first and second contact electrodes; an insulating support covering the side surfaces of the first and second bulk electrodes; a first wavelength converter covering the light-emitting structure; a light-transmitting layer positioned on the first wavelength converter; and a second wavelength converter positioned on the light-transmitting layer, and, in the present invention, white light emitted from the light-emitting element has a CIEx value of at least 0.390 on the CIE color coordinate chart.