Infrared detection MEMS flow sensor

Abstract

The present application relates to a kind of infrared detection MEMS flow sensor, including infrared radiation unit and infrared receiving unit;The infrared radiation unit includes the thin soft support of cantilever arrangement in pipeline and the hollow structure, heating resistance is hung in the head of thin soft support, blackbody is attached on heating resistance for the infrared wave of outward radiation, voltage source is arranged outside pipeline, two wires pass through thin soft support for connecting voltage source and heating resistance;The infrared receiving unit is MEMS infrared thermocouple sensor array, and receiving end is opposite blackbody, for absorbing the infrared wave radiated by blackbody, and convert into direct current voltage;In the present application, the blackbody for releasing infrared radiation is located inside the pipeline, and the MEMS infrared thermocouple sensor array for detecting fluid flow rate is located outside the pipeline, which has higher accuracy, lower heat pollution, lower waterproof and sealing requirements, lower cost, easier installation and other advantages when working.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow sensor, in particular to an infrared detection MEMS flow sensor. BACKGROUND

[0002] MEMS flow sensor chip is a flow sensor core device manufactured based on microelectronic technology (semiconductor manufacturing technology) and combined with micro-machining and precision machining technology. At present, the sensor chip based on MEMS technology has been widely used in industrial control, automotive electronics, medical devices, analytical instruments, air quality detection and other fields. Compared with traditional mechanical flow meter, MEMS flow sensor chip has the characteristics of small size, light weight, low power consumption, high reliability, easy integration and intelligentization.

[0003] However, the existing traditional thermistor or thermoelectric pile type MEMS flow sensor usually needs to be waterproofed and contacted with the liquid in the pipeline. When working, the sensor first heats up by applying voltage to form a stable temperature distribution. When the liquid flows through the sensor, it will take away part of the heat, break the original stable temperature distribution, and form a temperature difference on both sides of the sensor, thereby generating an output electric signal. Since the existing thermistor or thermoelectric pile type MEMS flow sensor needs to be waterproofed and contacted with the liquid in the pipeline, it will be affected and disturbed by the environment, and will cause reliability problems. Moreover, the sensor has a part of the substrate film structure which is very thin and will cause the sensor to be damaged during assembly. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide an infrared detection MEMS flow sensor.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: an infrared detection MEMS flow sensor, comprising an infrared radiation unit and an infrared receiving unit.

[0006] The infrared radiation unit comprises a thin and soft support which is cantilevered in the pipeline and has a hollow structure, a heating resistor which is arranged in the pipeline and suspended at the head of the thin and soft support, a black body which is attached to the heating resistor for radiating infrared waves outward, a voltage source which is arranged outside the pipeline, and two wires which pass through the thin and soft support for connecting the voltage source and the heating resistor.

[0007] The infrared receiving unit is a MEMS infrared thermoelectric pile sensor array, and the receiving end faces the black body, which is used to absorb the infrared waves radiated by the black body and convert them into direct current voltage.

[0008] Preferably, the black body is made on the heating resistor by sintering process.

[0009] Preferably, the black body material is a nano carbon tube black body.

[0010] Preferably, the carbon nanotube blackbody is composed of vertically arranged carbon nanotubes.

[0011] Preferably, the heating resistor is made of platinum.

[0012] Preferably, the MEMS infrared thermopile sensor array is composed of multiple MEMS infrared thermopile sensors; the multiple MEMS infrared thermopile sensors are arranged in a matrix and on the same plane.

[0013] Preferably, the MEMS infrared thermopile sensor uses silicon-based micromachining technology, with several thermocouples arranged on a silicon wafer support layer, and these thermocouples connected in series to form a thermopile.

[0014] Preferably, the thermopile has a cavity structure at its lower part.

[0015] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] 1. This invention uses infrared temperature measurement to obtain the flow rate of fluid, which has higher sensitivity compared with traditional thermistors and other methods;

[0017] 2. In this invention, the blackbody used to emit infrared radiation is located inside the pipe, while the MEMS infrared thermopile sensor array used to detect fluid flow rate is located outside the pipe. During operation, it is less affected by environmental interference, has less thermal pollution, and has higher accuracy.

[0018] 3. In this invention, since the MEMS infrared thermopile sensor array does not directly contact the fluid, the requirements for waterproofing and sealing are low, and it has the advantages of low cost and convenient installation. Attached Figure Description

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0020] Appendix Fig. 1 This is a cross-sectional view of the infrared detection MEMS flow sensor described in this invention.

[0021] Appendix Fig. 2 This is a top view of the infrared detection MEMS flow sensor described in this invention;

[0022] Appendix Fig. 3 This is a structural diagram of the MEMS infrared thermopile sensor array in this invention.

[0023] The components include: 1. MEMS infrared thermopile sensor array; 2. Fluid; 3. Voltage source; 4. Wire; 5. Blackbody; 6. Heating resistor; 7. Pipe; 8. Thin and flexible support. Detailed Implementation

[0024] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The application relates to an infrared detection MEMS flow sensor. Figs. 1-3 The infrared detection MEMS flow sensor comprises an infrared radiation unit and an infrared receiving unit.

[0026] The infrared radiation unit comprises a thin and soft support 8 arranged in a cantilever mode in a pipeline 7 and having a hollow structure, a heating resistor 6 arranged in the pipeline 7 and hung at the head of the thin and soft support 8, a black body 5 attached to the heating resistor 6 for radiating infrared waves outward, a voltage source 3 arranged outside the pipeline 7, and two wires 4 passing through the thin and soft support 8 for connecting the voltage source 3 and the heating resistor 6.

[0027] The infrared receiving unit is a MEMS infrared thermocouple sensor array 1, and the receiving end faces the black body 5, so as to absorb the infrared waves radiated by the black body 5 and convert the infrared waves into a direct current voltage.

[0028] Further, the heating resistor 6 is made of platinum, which has a large temperature coefficient, a high resistivity and stable chemical properties.

[0029] Further, the black body 5 is a nano carbon tube black body 5, which is composed of carbon nanotubes generated in a vertical arrangement, and has an infrared emissivity value of more than 0.99.

[0030] Further, the black body 5 is made on the heating resistor 6 through a sintering process, so that the connection strength can be greatly increased.

[0031] Further, the MEMS infrared thermocouple sensor array 1 is composed of a plurality of MEMS infrared thermocouple sensors; nine MEMS infrared thermocouple sensors are arranged in a 3*3 square mode and on the same plane; when each MEMS infrared thermocouple sensor receives infrared radiation emitted by the black body 5, a temperature difference is formed between the cold end and the hot end of the thermocouple, and then a direct current output voltage is converted; wherein the MEMS infrared thermocouple sensor can be used as a non-contact temperature measuring device, which can quickly measure the surface temperature of an object without directly contacting the object.

[0032] Further, the MEMS infrared thermocouple sensor is arranged on a silicon wafer support layer according to the Seebeck effect mechanism, and a plurality of thermocouples are connected in series to form a thermocouple.

[0033] Further, a cavity structure is arranged below the thermocouple for improving the thermal resistance and thus improving the sensitivity of the sensor.

[0034] Working time: first, the voltage source 3 supplies power to the heating resistor 6 through the two wires 4 inside the support, which is used to heat the black body 5, so that the black body 5 emits infrared radiation outward; at the same time, the MEMS infrared thermopile sensor array 1 is used to receive the infrared radiation released by the black body 5; when the fluid 2 flows through the pipeline 7, on the one hand, because the soft support 8 is soft, it will drive the black body 5 to move in the direction of the fluid 2 flow, resulting in a change in the opposite area of the black body 5 and the MEMS infrared thermopile sensor array 1, on the other hand, the fluid 2 will take away part of the infrared radiation energy released by the black body 5, so that the infrared radiation energy received by the MEMS infrared thermopile sensor array 1 changes, so that its output voltage changes accordingly; finally, the output voltage value of the MEMS infrared thermopile sensor array 1 is analyzed to obtain the flow rate of the fluid 2 at this time.

[0035] The above is only a specific application example of the present application, and does not constitute any limitation on the protection scope of the present application. Any technical solution formed by equivalent transformation or equivalent replacement falls within the protection scope of the present application.

Claims

1. An infrared detection MEMS flow sensor, characterized in that: It includes an infrared radiation unit and an infrared receiving unit; The infrared radiation unit includes a flexible support that is cantilevered inside the pipe and has a hollow structure, a heating resistor that is installed inside the pipe and suspended from the head of the flexible support, a blackbody attached to the heating resistor for radiating infrared waves outward, a voltage source installed outside the pipe, and two wires that pass through the flexible support for connecting the voltage source and the heating resistor. The blackbody is fabricated on a heating resistor by a sintering process, and the blackbody material is a carbon nanotube blackbody, which is composed of vertically arranged carbon nanotubes. The heating resistor is made of platinum; The infrared receiving unit is a MEMS infrared thermopile sensor array, and the receiving end faces the blackbody to absorb the infrared waves radiated by the blackbody and convert them into DC voltage. The MEMS infrared thermopile sensor array is composed of multiple MEMS infrared thermopile sensors; the multiple MEMS infrared thermopile sensors are arranged in a matrix and on the same plane; The MEMS infrared thermopile sensor uses silicon-based micromachining technology, with several thermocouples arranged on a silicon wafer support layer and connected in series to form a thermopile; a cavity structure is provided below the thermopile.

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