Optical Wavelength Conversion Device High Thermal Conductivity Joint
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Solution Overview
Problem
Optical wavelength conversion devices face challenges in maintaining efficient heat dissipation and joint strength due to temperature quenching and re-melting of solder or adhesives when exposed to high laser power, leading to defects and reduced heat transfer efficiency.
Innovation Solution
An optical wavelength conversion device with a plate-shaped ceramic fluorescent body, a reflecting film, and a joint portion made of gold, silver, or copper with a thermal conductivity of 120 W/mK or more and a melting point of 240°C or higher, which includes a porosity of 40% or less and an average thickness that is 50% or less of the total thickness, to enhance heat dissipation and prevent thermal shock and joint breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solder or resin-based adhesive is used to join the optical wavelength conversion member to the heat dissipation member, then the joint strength is maintained, but the joint melts or degrades at high temperatures causing reduction in joint strength and heat dissipation efficiency
Solution Approach 1:
The patent changes the material parameters of the joint portion by using metal particles (silver, aluminum, or copper) with specific thermal conductivity (120 W/mK or more) and melting point (240°C or higher) requirements. This parameter specification ensures the joint can withstand high temperatures from laser irradiation while maintaining mechanical strength and thermal dissipation performance.
Solution Approach 2:
The joint portion is formed as a composite structure containing metal particles dispersed in an adhesive matrix. This composite material combines the high temperature resistance and thermal conductivity of metal particles with the bonding capability of the adhesive, creating a joint that maintains both strength and heat resistance under laser irradiation conditions.
2Temperature
If silver nanoparticles are used to join the optical wavelength conversion member to the heat dissipation member, then the occurrence of defect due to re-melting of solder is prevented, but the heat transferability from the optical wavelength conversion member to the heat dissipation member is insufficient
Solution Approach 1:
The patent raises the thermal conductivity threshold to 120 W/mK or more, which is significantly higher than typical silver nanoparticle composites. This parameter change forces the selection of materials with superior thermal conductivity, such as aluminum or copper particles, thereby resolving the insufficient heat transferability while maintaining high heat resistance.
3Loss of energy
If the joint portion has high thermal conductivity to improve heat dissipation, then heat can be efficiently dissipated from the optical wavelength conversion member, but the joint may become weaker due to material selection constraints
Solution Approach 1:
The joint portion uses a composite structure where metal particles (silver, aluminum, or copper) provide high thermal conductivity pathways for heat dissipation, while the adhesive matrix maintains the bonding strength. This composite approach allows simultaneous achievement of high heat dissipation efficiency and joint strength.
Solution Approach 2:
The adhesive matrix acts as an intermediary that binds the metal particles together and to the substrate surfaces. This intermediary material enables the formation of a continuous joint structure that can transmit both mechanical loads and thermal energy, resolving the conflict between strength and thermal conductivity requirements.
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 effectively maintains high heat resistance and joint strength, ensuring efficient heat dissipation and preventing defects such as delamination or breakage, even under high laser power conditions, by using a high thermal conductivity and high melting point joint material with controlled porosity and thickness.
Implementation Method 1
The joint portion has a thermal conductivity of 120 W/mK or more
Implementation Method 2
a reflecting film that is disposed on a heat dissipation member-side surface of the ceramic fluorescent body
Implementation Method 3
white light is obtained by converting the wavelength of blue light from a light emitting diode (LED) or a semiconductor laser diode (LD) using a fluorescent body serving as an optical wavelength conversion member
Data Source
AI summary
An optical wavelength conversion device includes an optical wavelength conversion member configured to convert the wavelength of incident light; a heat dissipation member which is more excellent in heat dissipation than the optical wavelength conversion member; and a joint portion which joins the optical wavelength conversion member and the heat dissipation member together. The optical wavelength conversion member includes a plate-shaped ceramic fluorescent body and a reflecting film disposed on a heat dissipation member-side surface of the ceramic fluorescent body. The joint portion has a thermal conductivity of 120 W/mK or more. The joint portion has a melting point of 240° C. or higher.