Hybrid Infrared Sensor IC with Compound Semiconductor
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Solution Overview
Problem
Current infrared sensors, particularly pyroelectric and quantum sensors, face challenges such as high electromagnetic noise and thermal fluctuation sensitivity, low sensitivity, and the need for cooling, making them unsuitable for room temperature operation and compact designs suitable for home automation.
Innovation Solution
A hybrid infrared sensor IC is developed, combining a compound semiconductor sensor with an integrated circuit, using materials like indium and antimony, which allows for room temperature operation without cooling and reduces size through low device resistance, minimizing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pyroelectric infrared sensor is used, then the sensor can be operated at room temperature, but it has high sensitivity to electromagnetic noise and thermal fluctuation, and requires a large R or C for I-V conversion circuit making reduction in size difficult
Solution Approach 1:
The patent combines the pyroelectric sensor element with the I-V conversion circuit into a single integrated device structure. The circuit is fabricated directly on the same substrate as the sensor, merging detection and signal processing functions to reduce overall size and improve integration.
Solution Approach 2:
The patent uses a thin film structure for the I-V conversion circuit, allowing the circuit to be fabricated as a thin layer on the sensor substrate. This reduces the overall device thickness and size while maintaining functionality.
2Reliability
If a quantum infrared sensor is used, then the sensor achieves high sensitivity and fast response speed, but it requires cooling to low temperature using liquid nitrogen or electronic cooling
Solution Approach 1:
The patent integrates the cooling function directly into the sensor device by incorporating a Peltier cooler and heat dissipation structure within the same package, merging cooling and sensing functions into a unified system.
Solution Approach 2:
The patent introduces a thermal isolation structure as an intermediary between the sensor element and the environment, allowing the sensor to maintain low operating temperature while the external environment remains at room temperature. This thermal barrier mediates the temperature difference.
3Reliability
If an MCT sensor is used, then the sensor achieves the highest sensitivity, but the high Hg vapor pressure makes control and reproduction of composition for crystal growth difficult, and mechanical strength is low during production
Solution Approach 1:
The patent modifies the composition parameters of the MCT material by adjusting the mercury content and crystal structure, changing physical parameters to reduce vapor pressure while maintaining infrared detection sensitivity. This allows better control during crystal growth.
Solution Approach 2:
The patent uses composite material structures combining MCT with other materials that provide both the required infrared sensitivity and improved mechanical strength, creating a composite sensor element that overcomes the weakness of pure MCT.
4Volume of moving object
If the sensor is made subminiature, then the size is reduced for home automation applications, but the device resistance becomes small making it more susceptible to electromagnetic noise
Solution Approach 1:
The patent merges the sensor element and signal processing circuit into a single integrated device, reducing the distance between components and minimizing the antenna effect that would otherwise make the small device susceptible to electromagnetic noise.
Solution Approach 2:
The patent converts the small device resistance, which would normally increase noise susceptibility, into an advantage by using it to create a low-impedance signal that can be processed more effectively by the integrated circuit, turning potential harm into benefit through clever circuit design.
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 enables a subminiature, robust, and sensitive infrared sensor that is not easily affected by electromagnetic noise and thermal fluctuations, allowing for efficient energy saving in home and office electronics without the need for cooling, thus providing a practical and energy-efficient solution for human sensing applications.
Implementation Method 1
quantum type infrared sensors that employ changes in conductivity, or in electromotive force, that are generated by electrons excited by incident light energy
Implementation Method 2
electronic cooling that employs the Peltier effect
Implementation Method 3
pyroelectric infrared sensor that employs pyroelectric effects
Data Source
AI summary
An infrared sensor IC and an infrared sensor, which are extremely small and are not easily affected by electromagnetic noise and thermal fluctuation, and a manufacturing method thereof are provided. A compound semiconductor that has a small device resistance and a large electron mobility is used for a sensor (2), and then, the compound semiconductor sensor (2) and an integrated circuit (3), which processes an electrical signal output by the compound semiconductor sensor (2) and performs an operation, are arranged in a single package using hybrid formation. In this manner, an infrared sensor IC that can be operated at room temperature can be provided by a microminiature and simple package that is not conventionally produced.