An indium gallium arsenide infrared temperature sensor

Abstract

This utility model discloses an indium gallium arsenide (IGaAs) infrared temperature sensor, relating to the field of infrared temperature measurement technology. Specifically, it includes: leads, pins, and a base. The IGaAs infrared temperature sensor further includes: an IGaAs photodiode, which converts infrared signals into current signals; a signal processing unit, which converts the output current signal into a voltage signal; a housing, which covers the IGaAs photodiode and the signal processing unit; and a filter, which is disposed above the IGaAs photodiode. The housing is made of an opaque material and uses a low-magnetic-permeability metal, which can shield external magnetic field interference and improve temperature measurement accuracy. Under certain environmental conditions, the low-magnetic-permeability metal has low permeability and is not easily heated, while also shielding the detector and signal processing circuit from magnetic field interference.

Description

Technical Field

[0001] This utility model relates to the field of infrared temperature measurement technology, specifically to an indium gallium arsenide infrared temperature sensor. Background Technology

[0002] In modern kitchen appliances, especially induction cooking equipment, precise temperature control is crucial for cooking results. Traditional temperature measurement methods, such as thermocouples or thermistors, can provide temperature data, but they are usually slow to respond, have limited accuracy, and are easily affected by environmental factors. In contrast, indium gallium arsenide infrared temperature sensors can achieve non-contact temperature measurement without the obstruction of glass, can detect infrared light in the sensitive wavelength band, and can resist external interference such as water, water vapor, and oil fumes.

[0003] The patent (publication number: CN218180123U) discloses an infrared detector, including: a housing, an indium gallium arsenide photodetector unit and a filler, with an opening at the top of the housing; the indium gallium arsenide photodetector unit is disposed inside the housing, and the pins of the indium gallium arsenide photodetector unit are exposed from the bottom of the housing and electrically connected to an external circuit board.

[0004] Patent (Publication No.: CN221102102U) discloses an indium gallium arsenide infrared detector and temperature measurement module, including: an indium gallium arsenide photosensitive unit, a light-transmitting housing, and pins. The indium gallium arsenide photosensitive unit is used to receive infrared rays emitted by a target object and convert them into electrical signals. The housing covers the outer periphery of the indium gallium arsenide photosensitive unit, and at least part of its surface is curved to focus the infrared rays irradiated on the upper surface onto the photosensitive surface of the indium gallium arsenide photosensitive unit. The pins are electrically connected to the indium gallium arsenide photosensitive unit and are exposed from the housing.

[0005] Both of the above patents require the addition of operational amplifiers and peripheral circuitry for current / voltage conversion, signal amplification, and other processing before the signal can be recognized by the system. This approach results in a complex peripheral circuit structure, a larger overall temperature measurement module, and relatively long connecting lines between peripheral circuits. In some applications, such as induction heating, this can easily lead to signal interference and inaccurate temperature measurements.

[0006] In summary, it is necessary to develop an indium gallium arsenide infrared temperature sensor to solve the above problems. Utility Model Content

[0007] To address the shortcomings of existing technologies, the technical solution adopted by this utility model is: an indium gallium arsenide infrared temperature sensor, specifically comprising:

[0008] The indium gallium arsenide infrared temperature sensor also includes leads, pins, and a base.

[0009] An indium gallium arsenide photodiode, wherein the indium gallium arsenide photodiode is used to convert infrared signals into current signals;

[0010] The signal processing unit is used to convert a current signal into a voltage signal; wherein the current signal is output from an indium gallium arsenide infrared thermometer; and the indium gallium arsenide photodiode is used to receive infrared radiation emitted by the target object and convert it into a current signal.

[0011] A housing that encloses the indium gallium arsenide photodiode and the signal processing unit.

[0012] A filter is positioned above the indium gallium arsenide (IGaAs) photodiode. The filter's placement ensures that light entering the sensor passes through it first, effectively filtering out visible light and some unwanted infrared radiation, allowing only specific wavelengths of infrared light to reach the IGaAs photodiode. This improves temperature measurement accuracy, optimizes the signal acquisition process, and reduces interference. The lead wire is typically made of gold wire, but silver, copper, and aluminum are also acceptable. Its low resistivity ensures minimal loss of the weak current signal generated by the IGaAs photodiode during transmission to the signal processing unit, thus improving signal integrity and measurement accuracy. The lead wire also electrically connects the IGaAs photodiode and the signal processing unit, connects the power supply polarity and signal lines, and supports UART and HC communication. UART is a commonly used serial communication protocol that allows data communication between two devices via a serial interface.

[0013] Furthermore, the pins are exposed from the outer surface of the housing or base and are electrically connected to an external circuit board. These pins are internal output pins of the detector and are connected to external circuitry, including power lines and signal lines.

[0014] Furthermore, the infrared sensitive band of the indium gallium arsenide photodiode is <2.7µm. This indium gallium arsenide photodiode, by virtue of its sensitivity to infrared radiation in a specific band, can detect infrared radiation emitted by a target object. Its sensitive band is less than 2.7µm, enabling it to effectively detect infrared radiation even in situations with glass obstructions, thus achieving non-contact temperature measurement.

[0015] Furthermore, the signal processing unit is electrically connected to the pins via leads.

[0016] Furthermore, the housing is made of an opaque material. Since indium gallium arsenide photodiodes are sensitive to visible light and infrared light with wavelengths close to visible light, the opaque housing effectively filters out this ambient light, preventing it from adversely affecting the sensor's temperature measurement accuracy and improving the accuracy of temperature measurement.

[0017] Furthermore, the housing is made of a low-magnetic-permeability metal. This low-magnetic-permeability metal includes stainless steel, copper, aluminum, etc. In applications such as kitchens, various magnetic field sources exist. The housing made of a low-magnetic-permeability metal can shield these external magnetic fields, reducing interference from the magnetic field on the sensor's internal circuitry, improving temperature measurement accuracy, and preventing temperature measurement errors or signal instability caused by magnetic field interference.

[0018] Furthermore, the positive power supply terminal or the power supply reference ground terminal of the housing and the signal processing unit are fixedly connected.

[0019] Furthermore, the filter can transmit a portion of infrared light.

[0020] Furthermore, the signal processing unit includes:

[0021] The system comprises an operational amplifier, an MCU unit, and a temperature sensing device. The operational amplifier is electrically connected to the MCU unit and the temperature sensing device via wires. The operational amplifier amplifies and converts the weak current signal output from the indium gallium arsenide photodiode, making it easier for subsequent processing and measurement. The output signal is analog, facilitating integration into analog systems. The MCU unit performs digital processing such as filtering, compensation, and linearization on the signal, improving signal quality and temperature measurement accuracy. It has the ability to communicate with microcontrollers or digital systems via interfaces such as UART and I²C. The MCU unit internally includes a comparator circuit and a memory for storing alarm thresholds. These thresholds can be fixedly programmed or dynamically configured by external devices via interfaces such as UART and I²C. The temperature sensing device monitors the internal ambient temperature of the detector, providing real-time data for temperature measurement.

[0022] Furthermore, the filter is curved. Compared to a planar filter, the curved filter has a focusing effect, which can focus the incident infrared light, so that the infrared light can be more concentratedly irradiated onto the photosensitive surface of the indium gallium arsenide photodiode.

[0023] Furthermore, the filter is planar in shape; planar filters are less expensive and can filter visible light and infrared light with wavelengths close to visible light.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] 1. The signal processing unit and the indium gallium arsenide photodiode are packaged in the same housing, which significantly reduces the size, shortens the wiring length and area, reduces external interference, and lowers the cost. At the same time, the sensor as a whole does not require external operational amplifiers and peripheral circuits for signal processing, avoiding the problem of a large temperature measurement module and long connecting wires due to a complicated external circuit structure, and further avoiding the problem of signal interference.

[0026] 2. The housing is made of opaque material and uses low magnetic permeability metal, which can shield external magnetic field interference and improve temperature measurement accuracy. Under certain environmental conditions, the low magnetic permeability of the metal makes it difficult to be heated. At the same time, it can shield the magnetic field from interfering with the detector and signal processing circuit, reduce the area of ​​the pins directly exposed to the external magnetic field, and thus reduce the probability of magnetic impurities being attracted to the pins. In addition, the metal housing encapsulation scheme can shield the magnetic field from interfering with the internal components and wiring.

[0027] 3. The filter is located above the indium gallium arsenide photodiode. This layout ensures that the light entering the sensor passes through the filter first, effectively filtering out visible light and some unwanted infrared light, allowing only infrared light of specific wavelengths to reach the indium gallium arsenide photodiode, thus avoiding the problem of unwanted light affecting the indium gallium arsenide photodiode. The filter is designed with a curved shape to focus infrared light, enhance signal strength, improve photoelectric conversion efficiency and temperature measurement accuracy, while a planar filter reduces cost.

[0028] 4. The MCU unit has a built-in comparator and memory, and sets alarm thresholds. It outputs an alarm signal through a pin, which is received by the external main control system and triggers the alarm device. This design can effectively remind the user that the cooking equipment or the surface of the pot is too hot, preventing the user from leaving the induction cooker during cooking and causing the induction cooker to continue heating, thus further avoiding safety accidents. Attached Figure Description

[0029] Figure 1 This is the front view of this utility model;

[0030] Figure 2 This is a schematic diagram of the signal processing unit of this utility model;

[0031] Figure 3 This is a cross-sectional view of the curved surface filter of this utility model;

[0032] Figure 4 This is a schematic diagram of the structure of the filter of this utility model;

[0033] Figure 5 This is a cross-sectional view of the casing of this utility model;

[0034] Figure 6 This is a cross-sectional view of the planar filter of this utility model.

[0035] In the diagram: 41, Indium Gallium Arsenide Photodiode; 42, Lead; 43, Pin; 44, Base; 45, Signal Processing Unit; 451, Operational Amplifier; 452, MCU Unit; 453, Temperature Measuring Device; 46, Housing; 47, Filter. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical applications of the present invention, and to enable those skilled in the art to understand the present invention and design various embodiments with various modifications suitable for a particular purpose. Example 1

[0037] Please see Figure 1 - Figure 3 This utility model provides a technical solution: an indium gallium arsenide infrared temperature sensor, specifically comprising:

[0038] The indium gallium arsenide infrared temperature sensor also includes: lead wire 42, pin 43, and base 44.

[0039] Indium gallium arsenide photodiode 41, indium gallium arsenide photodiode 41 is used to convert infrared signals into current signals;

[0040] The signal processing unit 45 is used to convert the current signal into a voltage signal. The current signal is output from the indium gallium arsenide infrared temperature sensor. The indium gallium arsenide photodiode 41 is used to receive the infrared light emitted by the target object and convert it into a current signal. In this temperature sensor, the signal processing unit 45 and the indium gallium arsenide photodiode 41 are packaged in the same housing 46. Compared with placing the detector and peripheral circuits on the PCB board, the overall size of the detector can be significantly reduced, the wiring length and wiring loop area between the detector and the peripheral circuits can be shortened, and the number of peripheral devices can be reduced. The base 44 is used as a carrier to place the indium gallium arsenide photodiode 41 and the signal processing unit 45.

[0041] Housing 46 covers the outer surface of indium gallium arsenide photodiode 41 and signal processing unit 45;

[0042] Filter 47 is disposed above indium gallium arsenide photodiode 41. The placement of the filter 47 ensures that light entering the sensor passes through it first, effectively filtering out visible light and some unwanted infrared rays, allowing only infrared rays of specific wavelengths to reach the indium gallium arsenide photodiode 41. This improves temperature measurement accuracy, optimizes the signal acquisition process, and reduces interference signals. This layout also maintains the compactness of the sensor's overall structure, preventing a significant increase in sensor size due to the filter 47, facilitating installation and use. Furthermore, it provides some protection for the internal indium gallium arsenide photodiode 41, preventing external dust, oil, and other contaminants from directly contacting it and affecting its performance and lifespan. The lead wire 42 is typically made of gold wire, but silver, copper, aluminum, and other materials can also be used. Its low resistivity ensures minimal loss of the weak current signal generated by the indium gallium arsenide photodiode when transmitted to the signal processing unit, thereby improving signal integrity and measurement accuracy. The lead wire 42 electrically connects the indium gallium arsenide photodiode 41 and the signal processing unit 45, and can also connect the power supply positive and negative terminals and signal lines, supporting UART communication, HC communication, etc. UART is a commonly used serial communication protocol that allows two devices to communicate data through a serial interface.

[0043] Pin 43 is exposed on the outer surface of housing 46 or base 44 and is electrically connected to an external circuit board. Pin 43 is the internal output pin of the detector and is connected to external circuitry, including power lines and signal lines.

[0044] The infrared sensitive band of the indium gallium arsenide (IGaAs) photodiode 41 is <2.7µm. This IGaAs photodiode 41, by virtue of its sensitivity to infrared radiation in a specific band, can detect infrared radiation emitted by a target object. Its sensitive band is less than 2.7µm, allowing it to effectively detect infrared radiation even in situations with glass barriers, achieving non-contact temperature measurement. Compared to the infrared sensitive band of thermopile devices, it has stronger penetrating power and can resist external interference such as water, water vapor, and oil fumes. The IGaAs photodiode 41, as a detector chip, is a semiconductor photosensitive device mounted on the inner surface of the base 44.

[0045] The signal processing unit 45 is electrically connected to the pin 43 via the lead 42.

[0046] The housing 46 is made of an opaque material. Since the indium gallium arsenide photodiode 41 is sensitive to visible light and infrared light with wavelengths close to visible light, the opaque housing 46 can effectively filter out this ambient light, avoiding its adverse effect on the temperature measurement accuracy of the sensor and improving the accuracy of temperature measurement. At the same time, the housing 46 isolates ambient light, preventing external light from entering the interior of the housing 46 and avoiding light damage or photoelectric interference to the internal indium gallium arsenide photodiode 41 and signal processing unit 45.

[0047] The housing 46 is made of low-permeability metals, including stainless steel, copper, and aluminum. In applications such as kitchens, various magnetic field sources may exist. The housing 46, made of low-permeability metal, can shield these external magnetic fields, reducing interference from magnetic fields on the sensor's internal circuitry, improving temperature measurement accuracy, and preventing temperature measurement errors or signal instability caused by magnetic field interference. Under certain environmental conditions, the low permeability of low-permeability metals makes them difficult to magnetize and results in a weak response to magnetic fields. This can provide a certain degree of protection for the internal pins 43, reducing the area of ​​pins 43 directly exposed to external magnetic fields, thereby reducing the probability of magnetic impurities being attracted to pins 43. Low-permeability metals typically have high strength and good heat dissipation performance, providing better mechanical protection and heat dissipation for the sensor.

[0048] The positive power supply terminal or power supply reference ground terminal of the housing 46 and the signal processing unit 45 are fixedly connected.

[0049] Filter 47 allows some infrared light to pass through.

[0050] The surface of the filter 47 is planar. Planar filter 47 has a lower cost and can filter visible light and infrared light with wavelengths close to visible light.

[0051] Signal processing unit 45 includes:

[0052] The system comprises an operational amplifier 451, an MCU unit 452, and a temperature sensing device 453. The operational amplifier 451 is electrically connected to the MCU unit 452 and the temperature sensing device 453 via wires. The operational amplifier 451 outputs an analog signal, facilitating integration into analog systems. It amplifies and converts the weak current signal output by the indium gallium arsenide photodiode 41, making it easier for subsequent processing and measurement. The MCU unit 452 outputs a digital signal, performing digital processing such as filtering, compensation, and linearization to improve signal quality and temperature measurement accuracy. It has the ability to communicate with microcontrollers or digital systems via interfaces such as UART and I²C. The MCU unit 452 internally includes a comparator circuit and a memory for storing alarm thresholds. These thresholds can be fixedly programmed or dynamically configured by external devices via interfaces such as UART and I²C. The temperature sensing device 453 monitors the internal temperature of the detector, providing crucial data for temperature measurement by acquiring the detector's internal temperature in real time.

[0053] The working principle is as follows:

[0054] First, the indium gallium arsenide infrared temperature sensor is installed inside a cooking appliance such as an induction cooker, while the indium gallium arsenide photodiode 41 is located inside the sensor, facing the cooking area. During the cooking process, the target object, such as a pot or food, emits infrared rays, which are transmitted to the sensor location through the glass panel of the induction cooker or other media.

[0055] The indium gallium arsenide photodiode 41 is sensitive to infrared light in a specific wavelength band (infrared sensitive band <2.7μm), and can effectively receive and sense these infrared rays, then convert the received infrared rays into corresponding electrical signals. Because its sensitive infrared wavelength band has strong penetrating power, it can still ensure high signal quality even in environments with glass obstructions or interference factors such as moisture or oil fumes.

[0056] However, the indium gallium arsenide photodiode 41 is also sensitive to visible light and infrared light with wavelengths close to visible light. This portion of light is not beneficial for temperature measurement and needs to be filtered out. Therefore, by setting a filter 47, visible light and infrared light with wavelengths close to visible light can be filtered out, improving the accuracy of temperature measurement. Among them, the curved filter 47 can enhance the intensity of infrared light received by the photodiode and improve the photoelectric conversion efficiency. The focusing characteristics of the curved filter 47 make the sensor applicable to the temperature measurement of target objects of different distances and sizes, thereby improving the sensor's ability to detect weak infrared signals, especially in low-light or long-distance temperature measurement scenarios. The focused light path is more regular, which can reduce the generation of stray light and avoid unnecessary interference from stray light to the photodiode.

[0057] The electrical signal generated by the indium gallium arsenide photodiode 41 is relatively weak and needs to be transmitted to the signal processing unit 45 via lead 42. The operational amplifier 451 in the signal processing unit 45 amplifies and converts the weak current signal into a voltage signal that is easier to process and measure.

[0058] The amplified voltage signal is sent to the MCU unit 452 of the signal processing unit 45 for digital processing, converting the analog signal into a digital signal. The signal is then further processed, such as filtering, compensation, and linearization, to improve the signal quality and the accuracy of temperature measurement. The MCU unit 452 is equipped with a comparator circuit and a memory for storing alarm thresholds, which can compare the measured temperature value with the preset alarm threshold.

[0059] The temperature measuring device 453 in the signal processing unit 45 monitors the ambient temperature inside the detector in real time and feeds back the temperature data to the MCU unit 452.

[0060] Finally, the processed temperature data can be transmitted to an external main control system or other display devices through the output interface (such as UART, I²C, etc.) of the signal processing unit 45 to realize real-time monitoring and display of temperature information. When the measured temperature exceeds the preset alarm threshold, the MCU unit 452 triggers an alarm action and outputs an alarm signal to the external main control system through pin 43. After receiving the alarm signal, the external main control system drives the corresponding alarm devices, such as buzzers and indicator lights, to emit audible and visual alarms, reminding the user to take appropriate measures. The external main control system is the main control board inside the induction cooker, which is responsible for managing and controlling various functions of the induction cooker. It can receive alarm signals from pin 43 of the indium gallium arsenide infrared temperature sensor. Based on the received alarm signal, it controls the alarm devices inside the induction cooker to emit audible and visual alarms. When the temperature is high, it can effectively remind the user that the temperature is too high, preventing the user from leaving the area around the induction cooker during cooking and causing the induction cooker to continue heating, which could lead to safety accidents. Example 2

[0061] Please see Figure 1 - Figure 6 This utility model provides a technical solution: an indium gallium arsenide infrared temperature sensor, wherein the filter 47 is planar in shape; wherein, the planar filter 47 is less expensive than the curved filter 47, and can filter visible light and infrared light with wavelengths close to visible light. Figure 5 and Figure 6 There are two states in which the planar filter 47 is installed on the inner surface of the metal housing 46. In the first state, the filter 47 is embedded in the housing 46, and the light path is direct, which is suitable for high-precision temperature measurement scenarios. In the second state, the filter 47 is external, which is convenient for installation and replacement.

[0062] The working principle is as follows:

[0063] Finally, depending on the detector's photosensitive wavelength range, the filtering band of filter 47 also varies, as detailed below:

[0064] 1. When the detector's photosensitive wavelength is <2.7µm, the filter 47 filters wavelengths <2µm;

[0065] 2. When the detector's photosensitive wavelength is <2.2µm, the filter 47 filters a wavelength <1.7µm;

[0066] 3. When the detector's photosensitive band is <1.8um, the filter 47 filters a band <1.5um.

[0067] The relevant details are as follows:

[0068] By designing the coating material on the filter 47, this device can flexibly set the filtering range of the filter 47. However, due to current technological limitations, the epoxy resin housing 46 solution can only filter out light in the wavelength range below 940nm.

[0069] The indium gallium arsenide photodiode 41 and the signal processing unit 45 are integrated into a single package. This high integration reduces the overall cost of components, minimizes assembly steps, and lowers labor costs. Shorter interconnections between devices and a smaller circuit loop area compared to a separate structure reduce interference from the magnetic field generated by the induction heating coil, significantly minimizing interference from external magnetic fields. Furthermore, the metal casing design, with the metal casing connected to the positive and negative terminals of the power supply lines, effectively shields the internal components and interconnections from magnetic field interference.

[0070] Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of this utility model without creative effort should fall within the protection scope of this utility model. Structures, devices, and operating methods not specifically described and explained in this utility model, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. An indium gallium arsenide infrared temperature sensor, specifically comprising: The indium gallium arsenide infrared temperature sensor comprises a lead wire (42), a pin (43), and a base (44), characterized in that it further includes: An indium gallium arsenide photodiode (41) is used to convert infrared signals into current signals; Signal processing unit (45), the signal processing unit (45) is used to convert the output current signal into a voltage signal; A housing (46) surrounds the indium gallium arsenide photodiode (41) and the signal processing unit (45); A filter (47) is disposed above an indium gallium arsenide photodiode (41).

2. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The pin (43) is exposed from the outer surface of the housing (46) or the base (44) and is electrically connected to an external circuit board.

3. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The infrared sensitive band of the indium gallium arsenide photodiode (41) is <2.7um.

4. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The signal processing unit (45) is electrically connected to the pin (43) via a lead (42).

5. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The shell (46) is made of an opaque material.

6. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The housing (46) is made of a low-magnetic-permeability metal.

7. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The positive power supply terminal or power supply reference ground terminal of the housing (46) and the signal processing unit (45) are fixedly connected.

8. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The filter (47) can transmit some infrared light.

9. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The filter (47) is curved.

10. The indium gallium arsenide infrared temperature sensor according to claim 1, characterized in that: The filter (47) is planar in shape.

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