GaN Optical Coupler Packaging for High-Temperature Signal Isolation
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Solution Overview
Problem
Traditional optical couplers using infrared light-emitting diodes from the GaAs material system lack high-temperature resistance, making them unsuitable for applications in high-temperature environments.
Innovation Solution
An optical coupler design utilizing GaN-based light-emitting diodes with an indium gallium nitride/gallium nitride multiple quantum well structure, combined with a thixotropic light-transmitting resin inner package and a black outer package to enhance high-temperature resistance and prevent external light interference, maintaining a current transfer ratio of 60% or more at 150°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If infrared light-emitting diodes from the GaAs material system are used, then the optical coupler achieves good low-temperature performance and low noise, but the high-temperature resistance deteriorates
Solution Approach 1:
The patent changes the material parameter from GaAs to GaN-based materials, which fundamentally alters the temperature resistance characteristics. GaN materials inherently possess higher thermal stability and can operate reliably at temperatures up to 150°C or higher, directly resolving the high-temperature resistance issue while maintaining the electroluminescence function needed for optical coupling.
Solution Approach 2:
The patent employs composite material structures including GaN-based light-emitting diodes combined with thixotropic light-transmitting resin packages. This composite approach integrates materials with complementary properties: GaN provides high-temperature stability while the thixotropic resin provides optical transmission and structural support, achieving both low-temperature performance and high-temperature resistance.
2Temperature
If GaN-based light-emitting diodes are used, then the high-temperature resistance is improved, but the response efficiency of photosensitive devices deteriorates
Solution Approach 1:
The patent optimizes the emission wavelength parameter of the GaN-based LED to fall within the 380-500nm range, which matches the peak sensitivity region of silicon-based photosensitive devices. This parameter optimization ensures that despite the material change, the optical coupling efficiency and response efficiency are maintained or even improved compared to traditional infrared systems.
Solution Approach 2:
The patent substitutes the traditional infrared optical detection mechanism with a visible/near-UV wavelength detection system. By changing the optical wavelength regime from infrared (where GaAs operates) to visible/near-UV (where GaN operates), the system leverages the higher quantum efficiency of silicon photosensitive devices in this wavelength range, compensating for any potential losses from the material transition.
3Temperature
If thixotropic light-transmitting resin is used for the inner package, then the high-temperature resistance and light transmission are improved, but the device complexity increases
Solution Approach 1:
The patent selects thixotropic resin with specific parameter ranges: viscosity of 100-10000 cP at 25°C and Shore hardness of 40-80. These parameter specifications ensure the resin provides adequate high-temperature stability and optical transmission while maintaining processability during assembly. The thixotropic property allows the resin to be easily applied and then set in place, simplifying the packaging process despite the enhanced material properties.
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 GaN-based optical coupler achieves improved high-temperature resistance and balanced cost-efficiency by using GaN-based light-emitting diodes with specific emission wavelengths, maintaining a high current transfer ratio at elevated temperatures while preventing external light interference.
Implementation Method 1
The signal input unit includes a first metal bracket and a gallium nitride (GaN)-based light-emitting diode chip disposed on the first metal bracket, the GaN-based light-emitting diode chip acts as an optical signal emitter
Implementation Method 2
a gallium nitride (GaN)-based light-emitting diode chip disposed on the first metal bracket, the GaN-based light-emitting diode chip acts as an optical signal emitter
Implementation Method 3
the photosensitive device chip acts as an optical signal receiving and current converter
Implementation Method 4
the inner package forms a light transmission path located between the GaN-based light-emitting diode chip and the photosensitive device chip
Data Source
AI summary
An optical coupler includes: a signal input unit including a first metal bracket and a gallium nitride (GaN)-based light-emitting diode chip disposed thereon, the GaN-based light-emitting diode chip acting as an optical signal emitter and electrically connected to the first metal bracket; a signal output unit including a second metal bracket and a photosensitive device chip disposed thereon, the photosensitive device chip acting as an optical signal receiving and current converter and electrically connected to the second metal bracket; an inner package covering the GaN-based light-emitting diode chip and the photosensitive device chip and forming an optical transmission path between the GaN-based light-emitting diode chip and the photosensitive device chip; and an outer package covering the inner package, the GaN-based light-emitting diode chip and the photosensitive device chip, and partially covering the first metal bracket and the second metal bracket to expose pins of the first and second metal brackets.