Thin Light Extracting Layer for Deep UV LED Packaging
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Solution Overview
Problem
Conventional deep ultraviolet light-emitting diode package structures face high costs due to expensive quartz cover plates and reduced light extraction efficiency due to air-filled recesses and thick organic material layers, which also degrade over time.
Innovation Solution
A light-emitting device with a panel substrate, a light-emitting chip, and a thin light extracting layer that covers the chip and substrate, featuring a side portion that decreases in thickness outwardly and is doped with viscosity-adjusting particles, along with a blocking structure and glue-phobic layer to enhance light extraction and prevent material spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cup-shaped substrate with air-filled recess and quartz cover plate is used, then the deep ultraviolet light-emitting diode is sealed and protected, but the manufacturing cost increases and light extraction efficiency decreases due to total reflection
Solution Approach 1:
The patent replaces expensive quartz cover plates with a molded organic material layer that serves as both the sealing cover and the light extracting layer. This substitution dramatically reduces manufacturing costs while maintaining the necessary sealing and protection functions for the deep ultraviolet light-emitting diode.
Solution Approach 2:
The patent changes the optical parameters of the packaging material by using organic materials with specific refractive indices and absorption coefficients that are optimized for deep ultraviolet light extraction. The organic material layer has controlled thickness (10-200 μm) and optical properties that prevent total reflection while maintaining sealing, thereby improving light extraction efficiency compared to quartz.
2Reliability
If a thick organic material layer is used to cover the light-emitting diode, then the sealing is improved, but the light extraction efficiency decreases due to light absorption
Solution Approach 1:
The patent optimizes the thickness parameter of the organic material layer to fall within 10-200 μm. This controlled thickness ensures sufficient sealing protection while minimizing light absorption. The organic material's optical parameters (refractive index, absorption coefficient) are selected and adjusted to achieve optimal light extraction efficiency for deep ultraviolet wavelengths.
Solution Approach 2:
The patent uses organic materials with specific compositional characteristics that combine adequate sealing properties with low ultraviolet absorption. The material composition is engineered to balance these competing requirements, creating a composite structure that provides both protection and efficient light extraction.
3Reliability
If a thick organic material layer is used to cover the light-emitting diode, then the sealing is improved, but the lifetime duration decreases due to material degradation from ultraviolet absorption
Solution Approach 1:
The patent selects organic materials with specific optical and chemical parameters that exhibit high resistance to ultraviolet-induced degradation. The material's absorption coefficient is optimized to balance light extraction needs with long-term stability. By controlling material composition and thickness, the patent achieves both adequate sealing and enhanced durability against UV degradation.
Solution Approach 2:
The patent employs molded organic materials that, while less expensive than quartz, are engineered for improved long-term stability through careful selection of materials with high UV resistance. The material formulation includes components specifically chosen to resist degradation, extending the operational lifetime of the packaged 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 significantly improves light extraction efficiency and extends the device's lifetime by using a thin light extracting layer and strategically placed blocking and glue-phobic layers, reducing material costs and preventing degradation.
Implementation Method 1
the light emitted from the deep ultraviolet light-emitting diode is prone to be totally reflected by the cover plate. As a result, the light extraction rate of the package structure is reduced
Implementation Method 2
the organic material layer formed in this manner is too thick, so that the light emitted from the deep ultraviolet light-emitting diode is absorbed by the organic material layer
Data Source
AI summary
A light-emitting device includes a panel substrate, a light-emitting chip, and a light extracting layer. The light-emitting chip is disposed on the panel substrate. The light extracting layer covers the light-emitting chip and the panel substrate, and the light extracting layer has a side portion. Taking the position where the edge of the light-emitting chip is in contact with the panel substrate as the origin, the side portion and the origin define a circle tangential to the surface of the side portion. The circle has a radius c which satisfies the following formula (1):140H≤c≤H(1)where H is a height of the light-emitting chip. The light-emitting device disclosed herein has a light extracting layer having a very small thickness, and provides excellent light-emitting efficiency and lifetime of the light-emitting device.