Avalanche Photodiode Gain Stabilization via Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Avalanche photodiodes in medical laser receivers experience unstable voltage gain due to temperature changes, leading to measurement errors, particularly when used in medical devices that require direct contact with the human body, and existing solutions like thermoelectric coolers increase device size and power consumption.
Innovation Solution
A method that generates a high-voltage bias for an avalanche photodiode, detects temperature, and controls variable resistance to maintain a stable voltage gain by comparing output voltage data with a reference voltage, eliminating the need for a thermistor and current supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thermoelectric cooler is used to maintain constant temperature of the avalanche photodiode, then temperature stability is improved, but device size and power consumption increase
Solution Approach 1:
The patent changes the operating parameters of the avalanche photodiode by adjusting the reverse bias voltage dynamically based on temperature compensation curves. Instead of maintaining constant temperature through cooling, the system compensates for temperature effects by modifying the electrical parameters (voltage gain) to counteract temperature-induced variations, thereby achieving stable output without thermal management hardware
Solution Approach 2:
The patent extracts and removes the thermoelectric cooler and temperature sensor components from the system. By eliminating these thermal management components, the device size is reduced while maintaining measurement stability through electrical parameter adjustment based on pre-stored temperature compensation data
2Stability of the object's composition
If a thermoelectric cooler is used to maintain constant temperature of the avalanche photodiode, then temperature stability is improved, but power consumption increases
Solution Approach 1:
The system compensates for temperature effects by dynamically adjusting the reverse bias voltage parameter of the avalanche photodiode according to pre-stored compensation curves. This electrical parameter adjustment replaces the need for active thermal management, significantly reducing power consumption while maintaining measurement stability
Solution Approach 2:
The system uses pre-stored temperature compensation curves to automatically adjust operating parameters based on detected temperature changes. This self-compensation mechanism eliminates the need for external power-consuming cooling systems, as the avalanche photodiode's characteristics are corrected through electrical parameter adjustment rather than thermal control
3Reliability
If backward voltage is increased to achieve high amplitude ratio, then light receiving gain is improved, but the risk of burning out the avalanche photodiode increases
Solution Approach 1:
The patent dynamically adjusts the reverse bias voltage of the avalanche photodiode based on temperature conditions using pre-stored compensation curves. Instead of operating at a fixed high voltage that maximizes gain but risks burnout, the system continuously adapts the voltage parameter to maintain optimal performance while staying within safe operating limits under varying temperature conditions
4Adaptability or versatility
If the avalanche photodiode is used for direct contact measurement with curved body parts, then measurement capability is improved, but measurement accuracy decreases due to temperature changes
Solution Approach 1:
The system compensates for temperature-induced measurement errors by adjusting the reverse bias voltage parameter according to pre-stored compensation curves that account for temperature effects. This parameter adjustment maintains measurement accuracy even when the device is in direct contact with curved body parts that experience rapid temperature changes
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 approach reduces manufacturing costs and device size while preventing measurement errors by stabilizing voltage gain, enabling precise light measurement on curved body parts without the need for thermoelectric coolers.
Implementation Method 1
an avalanche photodiode (APD) is a photodiode having rapid speed and high response characteristics, and is an element that internally generates an electrical signal by adjusting amplitude ratio according to a change in backward voltage
Implementation Method 2
an avalanche photodiode that mostly uses a reverse bias voltage of not less than 100 V is used to achieve an avalanche photodiode having a high light receiving gain
Data Source
AI summary
The present invention provides a method for stabilizing the gain of an avalanche photodiode in a medical laser diode receiver. This method is characterized by comprising: (a) a step in which a high-voltage generation unit generates a high-voltage bias and applies same to an avalanche photodiode; (b) a step in which a temperature sensor senses the temperature of the avalanche photodiode; (c) a step in which a control unit controls a variable resistance value, which varies the voltage of the high-voltage bias, according to the value of the sensed temperature; (d) a step in which to detect if an output voltage signal is equivalent to the intensity of light received by the avalanche photodiode; and (e) a step in which a storage unit matches the sensed temperature value with the controlled variable resistance value and stores same. The present invention allows a reduction in production costs and also a significant reduction in the size of a measuring device itself. In addition, the present invention can prevent measurement errors by stabilizing the voltage gain of the avalanche photodiode and can promote precise diagnosis by accurately measuring scattered light even in a highly curved part of a human body to be measured by passing the light of a laser diode therethrough.