CN212903385U - Temperature difference type gas flow sensor based on MEMS - Google Patents
Temperature difference type gas flow sensor based on MEMS Download PDFInfo
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- CN212903385U CN212903385U CN202022368269.9U CN202022368269U CN212903385U CN 212903385 U CN212903385 U CN 212903385U CN 202022368269 U CN202022368269 U CN 202022368269U CN 212903385 U CN212903385 U CN 212903385U
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- 238000010438 heat treatment Methods 0.000 claims abstract description 61
- 238000005259 measurement Methods 0.000 claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 14
- 239000012528 membrane Substances 0.000 claims description 2
- 238000009529 body temperature measurement Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 2
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- 229910052581 Si3N4 Inorganic materials 0.000 description 1
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- 229910052737 gold Inorganic materials 0.000 description 1
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- 230000010354 integration Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
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- 239000010409 thin film Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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Abstract
The present disclosure provides a temperature differential gas flow sensor based on MEMS, the temperature differential gas flow sensor includes: a substrate including a first surface and a second surface oppositely disposed in a thickness direction thereof; the heating element is arranged on the first surface in a suspended mode; the temperature difference measurement component is arranged on the outer side of the heating element to output the gas flow information of the gas to be measured according to the generated temperature difference information of the gas to be measured flowing through. On one hand, the temperature difference type gas flow sensor is based on an MEMS structure, so that the whole temperature difference type gas flow sensor is compact in structure; on the other hand, the heating element arranged in the air can greatly reduce the power consumption of the gas flow sensor in use; on the last hand, the principle of measuring the gas flow by temperature difference is adopted, so that the flow measurement precision and the measurement range can be greatly improved, and the method can be widely applied to various fields of automobiles, biology, medical treatment, consumer electronics and the like.
Description
Technical Field
The utility model belongs to the technical field of the sensor, concretely relates to temperature difference type gas flow sensor based on MEMS.
Background
The gas flow meter is widely applied to various fields of automobiles, aerospace, medical treatment, chemical engineering, biology and the like, and occupies an important position in national economy. With the progress of society and the development of science and technology, the characteristics of miniaturization, integration, low cost, low power consumption, high precision and the like of a gas flowmeter chip will become the inevitable trend of market demands.
The flowmeter mainly used in the traditional industry in the market at present comprises a turbine flowmeter, a Roots flowmeter, a diaphragm flowmeter and the like, although the flowmeter has mature technology and can meet the general requirements on the precision, the sensitivity, the precision and the volume of the mechanical flowmeter cannot meet the requirements in the fields of biology, medical treatment, automobiles and the like.
Although MEMS-based flow sensors are also available in the market, the principle of pressure sensors is basically applied, and the main disadvantages of the MEMS-based flow sensors include low accuracy, small sensitivity and small measuring range.
SUMMERY OF THE UTILITY MODEL
The present disclosure is directed to solving at least one of the problems of the prior art and to providing a MEMS-based gas flow sensor.
The present disclosure provides a temperature differential gas flow sensor based on MEMS, the temperature differential gas flow sensor includes:
a substrate including a first surface and a second surface oppositely disposed in a thickness direction thereof;
the heating element is arranged on the first surface in a suspended mode;
the temperature difference measurement component is arranged on the outer side of the heating element to output the gas flow information of the gas to be measured according to the generated temperature difference information of the gas to be measured flowing through.
In some optional embodiments, the heating element is a heating resistor, and a heating wire of the heating resistor is configured as a suspended membrane structure to be suspended on the first surface.
In some optional embodiments, the temperature differential measurement assembly comprises at least one thermistor and at least one fixed resistor, the at least one thermistor and the at least one fixed resistor being electrically connected in a bridge configuration.
In some optional embodiments, the temperature difference measuring assembly comprises a plurality of thermistors and a plurality of fixed resistors, and the plurality of thermistors are symmetrically arranged on two sides of the heating element.
In some alternative embodiments, the distance between the plurality of thermistors and the heating element is adjustable to adjust the measurement accuracy and measurement range of the differential temperature gas flow sensor.
In some optional embodiments, the temperature difference measuring assembly comprises a first fixed resistor, a second fixed resistor, a first thermistor, and a second thermistor, the first fixed resistor, the second fixed resistor, the first thermistor, and the second thermistor being electrically connected in a wheatstone bridge configuration, in particular:
a first end of the first fixed resistor is electrically connected with a first output end and a first end of the first thermistor respectively, and a second end of the first fixed resistor is electrically connected with a grounding electrode of the Wheatstone bridge structure and a first end of the second fixed resistor respectively;
the second end of the second fixed resistor is electrically connected with a second output end and the first end of the second thermistor respectively;
and the second ends of the first thermistor and the second thermistor are electrically connected with the power supply electrode of the Wheatstone bridge structure.
In some optional embodiments, a first end of the heating element is electrically connected to the first heating electrode, and a second end of the heating element is electrically connected to the second heating electrode.
In some optional embodiments, the thermistor is a negative temperature coefficient thermistor.
In some optional embodiments, the second surface is provided with a groove at a position corresponding to the heating element.
In some alternative embodiments, the grooves are trapezoidal in cross-section.
According to the MEMS-based temperature difference type gas flow sensor, on one hand, the whole temperature difference type gas flow sensor is compact in structure due to the fact that the MEMS-based temperature difference type gas flow sensor is based on an MEMS structure; on the other hand, the heating element arranged in the air can greatly reduce the power consumption of the gas flow sensor in use; on the last hand, the principle of measuring the gas flow by temperature difference is adopted, so that the flow measurement precision and the measurement range can be greatly improved, and the method can be widely applied to various fields of automobiles, biology, medical treatment, consumer electronics and the like.
Drawings
FIG. 1 is a schematic diagram of a MEMS-based gas flow sensor according to one embodiment of the present disclosure;
FIG. 2 is an overall layout view of a MEMS based temperature differential gas flow sensor according to another embodiment of the present disclosure;
fig. 3 is a schematic diagram of the operation of a MEMS-based temperature differential gas flow sensor according to another embodiment of the present disclosure.
Detailed Description
For a better understanding of the technical aspects of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
As shown in fig. 1, a MEMS-based gas flow sensor 100 includes a substrate 110, a heating element 120, and a temperature differential measurement assembly 130. referring to fig. 1, as shown in fig. 1, the MEMS-based gas flow sensor 100 includes a substrate 110, a heating element 120, and a temperature differential measurement assembly 130.
For example, the substrate 110 may be made of silicon, or the substrate 110 may also be made of sapphire, and the like, which is not limited in this embodiment. As shown in fig. 1, the substrate 110 includes a first surface 111 and a second surface 112 oppositely disposed along a thickness direction thereof, that is, as shown in fig. 1, an upper surface of the substrate 110 may be the first surface 111, and correspondingly, a lower surface of the substrate 110 is the second surface 112, it should be noted that relevant dimensions of the substrate 110 are not limited, for example, the substrate 110 may have a size range of (1mm to 2mm) (1mm to 2mm), and the substrate 110 may preferably have a size range of 1.5mm × 1.5 mm.
For example, as shown in fig. 1, the heating element 120 is suspended on the first surface 111, for example, the heating element 120 may be designed as a suspended film structure to be suspended on the first surface 111, and the suspended heating element 120 can effectively prevent heat from being directly conducted out through the substrate 110 when it is heated, thereby greatly reducing heat loss and providing the most stable heat source for the sensor with the lowest power consumption.
Illustratively, as shown in fig. 1, the temperature difference measuring assembly 130 is disposed outside the heating element 120 to output gas flow information of the gas to be measured according to temperature difference information generated by the gas to be measured flowing through.
Specifically, when the gas flow rate is actually measured by using the temperature-difference gas flow sensor 100 of the present embodiment, as shown in fig. 1, the heating element 120 is heated to generate stable heat, and at this time, when the gas flow is to be measured, since the heat is transmitted in the fluid along the fluid moving direction, the temperature difference measuring component 130 can measure the temperature difference at different positions along the fluid flowing direction, so as to output an electrical signal according to the temperature difference, so as to determine the fluid flow rate information by using the electrical signal.
On one hand, the temperature difference type gas flow sensor of the embodiment is based on the MEMS structure, so that the whole temperature difference type gas flow sensor has a compact structure; on the other hand, the heating element arranged in the air can greatly reduce the power consumption of the gas flow sensor in use; on the last hand, the gas flow sensor adopts the principle of measuring the gas flow by temperature difference, can greatly improve the flow measurement precision and the measurement range, and can be widely applied to various fields of automobiles, biology, medical treatment, consumer electronics and the like.
For example, as shown in fig. 1 and fig. 2, the heating element 120 may employ a heating resistor, a heating wire of the heating resistor is configured as a suspended film structure to be suspended on the first surface 111, and a thin film of the suspended film structure may employ a silicon nitride material or the like. In order to improve the heating efficiency of the heating resistor, as shown in fig. 2, the heating wire may be formed on the first surface 111 by winding back and forth, so as to greatly increase the length of the heating wire in a limited space, thereby effectively improving the heating efficiency of the heating resistor.
Illustratively, as shown in fig. 1 and 2, the temperature difference measuring assembly 130 includes a plurality of thermistors and a plurality of fixed resistors, which are electrically connected in a bridge configuration.
It should be noted that, the number of the thermistors and the fixed resistors included in the temperature difference measuring assembly is not limited, for example, the temperature difference measuring assembly may include one, two, three or more thermistors and fixed resistors, which may be determined according to actual needs, and the embodiment is not limited thereto. In addition, the bridge structure formed by the thermistor and the fixed resistor is not particularly limited, for example, the thermistor and the fixed resistor may be electrically connected to form a single bridge structure, a wheatstone bridge structure, or the like, and may be designed according to actual needs, which is not limited in this embodiment.
It should be further noted that, no limitation is made on the type of the thermistor, and in the present embodiment, the thermistor may preferably be a negative temperature coefficient thermistor. The present embodiment does not specifically limit this.
Specifically, as shown in fig. 2, the temperature difference measuring assembly 130 may include a first fixed resistor R1, a second fixed resistor R2, a first thermistor RT1, and a second thermistor RT2, wherein the first fixed resistor R1, the second fixed resistor R2, the first thermistor RT1, and the second thermistor RT2 are electrically connected to form a wheatstone bridge structure, specifically:
as shown in fig. 2, the first end of the first fixed resistor R1 and the first output end V are respectivelyOUT1 (the first output terminal may be an output negative electrode) and a first terminal of the first thermistor RT1, and a second terminal of the first fixed resistor R2 is electrically connected to the ground electrode E1 of the wheatstone bridge structure and a first terminal of the second fixed resistor R2, respectively. The second end of the second fixed resistor R2 is respectively connected with the second output end VOUT2 (the second output terminal may be an output positive electrode) and a first terminal of the second thermistor RT 2. The first thermistor RT1 and the second thermistor RT2 are located at two sides of the heating element 120, and the second ends of the first thermistor RT1 and the second thermistor RT2 are electrically connected to the power supply electrode E2 of the wheatstone bridge structure. The first end of the heating element 120 is electrically connected to the first heating electrode T1, and the second end of the heating element 120 is electrically connected to the second heating electrode T2.
The working principle of the temperature-difference gas flow sensor 100 of the present embodiment will be described with reference to fig. 3.
As shown in FIG. 3, when a stable voltage is applied between the first heating electrode T1 and the second heating electrode T2 as the heating voltage of the sensor, the heating element 120 (heating resistor) will generate a stable heat, and a stable voltage is applied between the ground electrode E1 and the power supply electrode E2 as the measuring voltage of the sensor, and the Wheatstone bridge structure forms a current loop, when the sensor is in static equilibrium, the first output terminal V is connected to the first output terminal VOUT1 and a second output terminal VOUT2, and the voltage is 0V. When air flow passes through the sensor from left to right (as shown by an arrow A), the temperature above the first thermistor RT1 is lower than the temperature above the second thermistor RT2 because heat is transferred in the fluid along the moving direction of the fluid, the resistance of the first thermistor RT1 is greater than that of the second thermistor RT2, and the first output end V is connected with the first output end VOUT1 is lower than the second output terminal VOUT2, defining a first output terminal VOUT1 is the output cathode of the sensor, and the second output end VOUT2 is the output positive pole of the sensor, thatThe output voltage V0 is positive. In the same way, when the airflow passes through the sensor from right to left (as indicated by arrow B), the output voltage V0 is negative. Therefore, the temperature-difference gas flow sensor of the present embodiment can determine the magnitude and direction of the gas flow according to the magnitude and the positive and negative of the output voltage value.
The first output terminal, the second output terminal, the ground electrode, the feeding electrode, the first heating electrode, the second heating electrode, and the like described above may all be PADs made of a metal material, the area thereof may be 0.1mm by 0.08mm, and the material may be gold, platinum, aluminum, or the like. The present embodiment is designed with the six PADs in total to provide sufficient leads for the post-package bonding.
In order to further improve the sensitivity and measurement accuracy of the temperature-differential gas flow sensor, as shown in fig. 2, the first thermistor RT1 and the second thermistor RT2 may be symmetrically disposed at both sides of the heating element 120.
In order to further improve the measurement accuracy and the measurement range of the temperature-difference gas flow sensor, as shown in fig. 2, the distances between the first thermistor RT1 and the second thermistor RT2 and the heating element 120 are adjustable, so that the measurement accuracy and the measurement range of the temperature-difference gas flow sensor can be adjusted.
Illustratively, as shown in fig. 1, the second surface 112 is provided with a groove 113 at a position corresponding to the heating element 120. Preferably, the groove 113 has a trapezoidal cross-section. The small top area of the recess 113 allows sufficient space for the thermistor to be located and the large bottom area allows for the maximum possible isolation temperature.
It is to be understood that the above embodiments are merely exemplary embodiments that are employed to illustrate the principles of the present disclosure, and that the present disclosure is not limited thereto. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the disclosure, and these are to be considered as the scope of the disclosure.
Claims (10)
1. A MEMS-based temperature differential gas flow sensor, the temperature differential gas flow sensor comprising:
a substrate including a first surface and a second surface oppositely disposed in a thickness direction thereof;
the heating element is arranged on the first surface in a suspended mode;
the temperature difference measurement component is arranged on the outer side of the heating element to output the gas flow information of the gas to be measured according to the generated temperature difference information of the gas to be measured flowing through.
2. The temperature-differential gas flow sensor as claimed in claim 1, wherein the heating element is a heating resistor, and a heating wire of the heating resistor is configured as a suspended membrane structure to be suspended on the first surface.
3. The thermoelectric gas flow sensor of claim 1, wherein the differential temperature measurement assembly comprises at least one thermistor and at least one fixed resistor electrically connected in a bridge configuration.
4. The thermoelectric gas flow sensor of claim 3, wherein the temperature differential measurement assembly comprises a plurality of thermistors and a plurality of fixed resistors, the plurality of thermistors being symmetrically disposed on either side of the heating element.
5. The thermoelectric gas flow sensor of claim 4, wherein a distance between the plurality of thermistors and the heating element is adjustable to adjust a measurement accuracy and a measurement range of the thermoelectric gas flow sensor.
6. The temperature-differential gas flow sensor as claimed in claim 3, wherein the temperature-differential measuring assembly comprises a first fixed resistor, a second fixed resistor, a first thermistor, and a second thermistor, the first fixed resistor, the second fixed resistor, the first thermistor, and the second thermistor being electrically connected in a Wheatstone bridge configuration, in particular:
a first end of the first fixed resistor is electrically connected with a first output end and a first end of the first thermistor respectively, and a second end of the first fixed resistor is electrically connected with a grounding electrode of the Wheatstone bridge structure and a first end of the second fixed resistor respectively;
the second end of the second fixed resistor is electrically connected with a second output end and the first end of the second thermistor respectively;
and the second ends of the first thermistor and the second thermistor are electrically connected with the power supply electrode of the Wheatstone bridge structure.
7. The temperature-differential gas flow sensor of claim 6, wherein a first end of the heating element is electrically connected to a first heater electrode and a second end of the heating element is electrically connected to a second heater electrode.
8. The thermoelectric gas flow sensor of any one of claims 3 to 7, wherein the thermistor is a negative temperature coefficient thermistor.
9. The thermoelectric gas flow sensor of any of claims 1 to 7, wherein the second surface is provided with a groove at a location corresponding to the heating element.
10. The temperature-differential gas flow sensor as claimed in claim 9, wherein the groove has a trapezoidal cross-section.
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| CN202022368269.9U CN212903385U (en) | 2020-10-22 | 2020-10-22 | Temperature difference type gas flow sensor based on MEMS |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113970613A (en) * | 2021-09-15 | 2022-01-25 | 苏州芯镁信电子科技有限公司 | Hydrogen sensor and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113970613A (en) * | 2021-09-15 | 2022-01-25 | 苏州芯镁信电子科技有限公司 | Hydrogen sensor and preparation method thereof |
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Address after: No. 100-17 Dicui Road, Liyuan Development Zone, Wuxi City, Jiangsu Province, 214000 Patentee after: Wuxi Xinling Microelectronics Co.,Ltd. Address before: Building 071, building 2142, creative industry park, Wuxi City, Jiangsu Province Patentee before: Wuxi Xinling Microelectronics Co.,Ltd. |
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