UV LED Packaging with Fluoropolymer Encapsulant
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Solution Overview
Problem
Current encapsulation methods for ultraviolet light emitting diodes (UV LEDs) are inadequate due to the lack of transparency and stability of typical epoxy resin materials, which lead to issues with light extraction efficiency and environmental protection, and fluoropolymers are difficult to fill voids and become fluid-like during packaging.
Innovation Solution
The use of ultraviolet transparent polymers, such as fluoropolymers like Cytop and Teflon AF, which are processed to adhere to the UV LEDs and their packages, providing protection and improving light extraction efficiency by being heated to become flowable and then cured, ensuring stability and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical epoxy resin materials are used for UV LED encapsulation, then the packaging process is simple, but the materials are not sufficiently transparent to UV radiation and quickly deteriorate under UV radiation
Solution Approach 1:
The patent changes the material parameters by selecting fluoropolymer resins with specific UV transparency and stability characteristics, replacing conventional epoxy resins. This parameter change enables the encapsulant to maintain optical properties and structural integrity under UV radiation while still being processable through standard packaging procedures.
Solution Approach 2:
The patent employs composite material strategies by formulating encapsulants that combine fluoropolymer resins with appropriate additives and modifiers. These composite formulations achieve both UV stability and processability, resolving the contradiction between material reliability and manufacturing ease.
2Reliability
If fluoropolymers are used as UV transparent encapsulants, then UV transparency and stability are improved, but the materials cannot easily fill voids and be fluid-like during packaging
Solution Approach 1:
The patent applies parameter changes by controlling the temperature and viscosity of the fluoropolymer encapsulant during the packaging process. By heating the encapsulant to appropriate temperatures, it becomes sufficiently fluid to fill voids and conform to device geometries, then cools to achieve the desired stable, UV-transparent final state.
Solution Approach 2:
The packaging process employs periodic action through controlled heating and cooling cycles. The encapsulant is heated to become fluid for void filling, then cooled to solidify and provide structural stability. This temporal sequence resolves the contradiction between fluidity during processing and stability in the final state.
3Strength
If an encapsulant is subjected to heating during LED assembly and curing process, then the device is protected and bonded, but drying of the encapsulant can induce stresses and cause cracking
Solution Approach 1:
The patent addresses this contradiction by carefully controlling the thermal parameters during assembly and curing. The fluoropolymer encapsulant is heated to temperatures sufficient for bonding but maintained within a range that prevents excessive stress development. The curing process parameters are optimized to achieve strong adhesion while minimizing differential expansion and contraction that could cause cracking.
Solution Approach 2:
The patent employs beforehand cushioning by designing the encapsulant formulation and packaging process to anticipate and compensate for thermal stresses. The material composition and curing schedule are pre-configured to accommodate thermal expansion differences between the encapsulant, LED chip, and substrate, preventing stress concentration and cracking during the bonding 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 solution enhances the operating lifetime of UV LEDs by providing a stable and transparent encapsulation that protects the devices from environmental factors and improves light extraction efficiency, maintaining optical and mechanical properties over time.
Implementation Method 1
the ultraviolet transparent polymer material can be processed to cause the ultraviolet transparent polymer material to adhere to the optoelectronic device and/or the device package
Implementation Method 2
processed to cause the ultraviolet transparent polymer material to adhere
Implementation Method 3
processed to cause the ultraviolet transparent polymer material to adhere to the optoelectronic device and/or the device package
Data Source
AI summary
A solution for packaging an optoelectronic device using an ultraviolet transparent polymer is provided. The ultraviolet transparent polymer material can be placed adjacent to the optoelectronic device and/or a device package on which the optoelectronic device is mounted. Subsequently, the ultraviolet transparent polymer material can be processed to cause the ultraviolet transparent polymer material to adhere to the optoelectronic device and/or the device package. The ultraviolet transparent polymer can be adhered in a manner that protects the optoelectronic device from the ambient environment.