TW202016519A - Air flow heat conduction measurement system - Google Patents

Abstract

An air flow heat conduction measurement system includes a micro-electromechanical detection module, a status switching module, and a central processing module. The micro-electromechanical has a thermoelectric element. The central processing module outputs an operation signal to the status switching module, which controls the thermoelectric element to be in a heating status or a detecting status according to the operation signal. In heating status, the thermoelectric element is heated. In detecting status, the thermoelectric element detects the heat conduction of air to generate a temperature variation signal, which is received by the central processing module. Therefore, without the need of an additional heater, the thermoelectric element is switched to heating or detecting statuses, so as to reduce the cost of the additional heater, assures the detection accuracy, reduce the square measure of chip, and improve the yield rate of products.

Description

Gas convection heat conduction measurement system

The invention relates to a measurement system, in particular to a gas convection heat conduction measurement system.

The thermal 流量 sensor is mainly composed of a heating element (heater) and a temperature 度 temperature sensing element (temperature sensor). Among them, when the thermal flow sensor is used for measurement, it needs to pass through the heating element through the external The driving current heats the temperature sensing element, and the movement of the body will take away the heat of the temperature sensing element, causing a change in the temperature of the temperature sensing element or a change in the heating power, which can measure the speed of the body or the speed of the body. Device.

However, when the thermal flow sensor measures the fluid, the temperature sensing element needs to be heated through the heating element for a long time. Since the temperature sensing element needs to be heated for a long time, the temperature sensing element will cause aging and resistance Drift and other conditions affect the measurement accuracy, so thermal flow sensors need regular calibration parameters to ensure measurement accuracy, but even with frequent calibration parameters, there are still temperature sensing elements with the use of The problem of gradual aging, therefore, it is still impossible to increase the service life of the thermal flow sensor.

In order to solve the above-mentioned problems, the present invention provides a gas convection heat conduction measurement system, which controls the thermoelectric element to heat or detect the state through the state switching module. The thermoelectric element can reduce the cost of additional heaters, ensure the accuracy of detection, Reduce wafer area and increase manufacturing yield.

An embodiment of the present invention provides a gas convection heat conduction measurement system, which includes: a microcomputer inductive measurement module having a substrate and a thermoelectric element disposed on the substrate; a state switching module coupled to Thermoelectric element; and a central processing module, which is coupled to the thermoelectric element and the state switching module, the central processing module outputs a control signal to the state switching module, and the state switching module controls the thermoelectric element to a heating state according to the control signal Or a detection state, in the heating state, the thermoelectric element is heated; in the detection state, the thermoelectric element detects gas heat conduction to generate a temperature change signal, and the central processing module receives the temperature change signal.

In one of the embodiments, the present invention further has an amplifier coupled between the thermoelectric element and the data acquisition unit. The amplifier is used to amplify the temperature change signal.

In one embodiment, the amplifier has a positive terminal and a negative terminal, the thermoelectric element has a first terminal and a second terminal, the positive terminal is coupled to the second terminal, and the negative terminal It is coupled to the state switching module, and the first terminal is coupled to a reference power terminal.

In one of the embodiments, the state switching module further has a delay state, and the delay state is after the detection state.

Through the above, the present invention controls the thermoelectric element to heat or detect the state through the state switching module, and then performs the detection by heating in a short time; thereby, ensuring the accuracy of detection.

Furthermore, the present invention does not require additional heaters, and only needs to control the thermoelectric elements through the state switching module to heat or detect the state; thereby, the system cost can be effectively reduced, and the chip area can be reduced and the manufacturing yield can be improved.

In addition, the amplifier of the present invention can be used for signal amplification and dual functions of controlling the status of thermoelectric elements.

In addition, the invention controls the thermoelectric element to be in a delayed state after detecting the side state, so as to prevent the thermoelectric element from being in an unstable state and continuing the subsequent heating state, so that the thermoelectric element generates an unstable temperature change signal; thereby, the thermoelectric element can be avoided The component outputs noise, which affects the detection accuracy of the connection, thereby improving the signal-to-noise ratio detected by the present invention.

In order to facilitate the description of the central idea of the present invention in the column of the above summary of the invention, it is expressed in a specific embodiment. In the embodiments, various objects are drawn according to the proportion, size, deformation or displacement suitable for description, rather than drawn according to the proportion of actual elements, which will be described first.

Please refer to FIG. 1 to FIG. 10, the present invention provides a gas convection heat conduction measurement system 100, which includes:

A microcomputer inductive measurement module 10 has a substrate 11 and a thermoelectric element 12 disposed on one side of the substrate 11. The thermoelectric element 12 has a first end 121 and a second end 122, the first end 121 is coupled At a reference power terminal 1, the reference power terminal 1 is used to provide a voltage signal to the thermoelectric element 12, and the voltage signal provided by the reference power terminal 1 is greater than 0 volts; in the embodiment of the present invention, the substrate 11 is silicon ); thermoelectric element 12 is a thermopile (thermopile); reference power supply terminal 1 provides 3.3 volts.

The thermoelectric element 12 has a plurality of thermoelectric units 123, and each thermoelectric unit 123 has a fan shape, wherein each thermoelectric unit 123 has a first surface 123a and a second surface 123b disposed oppositely, and a first side 123c and a On the second side 123d, the first surface 123a of each thermoelectric unit 123 faces the substrate 11, as shown in FIG.

Furthermore, the microcomputer inductance measuring module 10 further has an insulating member 13 which is provided on the substrate 11 and isolates the thermoelectric element 12 from the substrate 11 by the insulating member 13; further explained, the insulating member 13 is coated The first surface 123a, the second surface 123b, the first side 123c, and the second side 123d of each thermoelectric unit 123 have an etching hole 131 between two adjacent thermoelectric units 123, as shown in FIG. 1. The insulating member 13 is provided with a plurality of perforations 132 corresponding to the first side 123c of each thermoelectric unit 123. Each of the perforations 132 can provide gas entry, improve the gas exchange rate, and improve the sensitivity of sensing. In the embodiment of the present invention, the insulating member 13 is Silicon dioxide (SiO ₂ ).

A state switching module 20, which is coupled to the thermoelectric element 12, wherein, as shown in FIG. 9, the state switching module 20 can be directly electrically connected to the thermoelectric element 12; or as shown in FIG. 10, the state switching module 20 The electronic components are electrically connected to the thermoelectric elements 12, for example, the resistance and capacitance are electrically connected between the state switching module 20 and the thermoelectric elements 12. The detailed structure will be described later.

A central processing module 30 is coupled to the thermoelectric element 12 and the state switching module 20. The central processing module 30 has a data acquisition unit 31, wherein the central processing module 30 can output a control signal to the state switching module Group 20, the state switching module 20 controls the thermoelectric element 12 to a heating state or a detection state according to the control signal; when the thermoelectric element 12 is in the heating state, the thermoelectric element 12 is heated; when the thermoelectric element 12 is in the detection state, the thermoelectric element 12 The element 12 performs gas heat conduction detection to generate a temperature change signal. The data acquisition unit 31 receives and processes the temperature change signal to generate a temperature change information. In the embodiment of the present invention, the control signal is a voltage signal; the temperature change signal It is an analog voltage signal.

The central processing module 30 further has a time control unit 32. The time control unit 32 is provided with a heating time Th, a steady-state time Ts and a reading time Tm. The control signal determines the time period during which the thermoelectric element 12 is in the heating state according to the heating time Th Length; the control signal determines the length of the period in which the thermoelectric element 12 is in the detection state according to the steady state time Ts and the reading time Tm; in the embodiment of the present invention, the length of the heating time Th is greater than the period of the steady state time Ts, the steady state The period of time Ts is shorter than the period of reading time Tm. The period of reading time Tm is longer than the period of heating time Th, as shown in FIGS. 5 and 7; and the purpose of steady-state time Ts is to avoid the heating state. When switching to the detection state, the effect caused by unstable signal oscillation.

Furthermore, the state switching module 20 further has a delay state after the detection state, and the time control unit 32 further has a delay time To, the delay time To corresponds to the delay state, and the delay time To is later than the reading time Tm, wherein the control signal determines the length of the time period in which the thermoelectric element 12 is in a delayed state according to the delay time To. In the embodiment of the present invention, the length of the delay time To is greater than the length of the steady-state time Ts, and the length of the delay time To is less than The period length of the reading time Tm and the period length of the delay time To are less than the period length of the heating time Th; as shown in FIGS. 6 and 8. It should be noted that the setting of the delay time To allows the thermoelectric element 12 to continue to dissipate heat, thereby avoiding the problem that the thermoelectric element 12 outputs noise, which affects the accuracy of subsequent detection.

An amplifier 40 is coupled between the thermoelectric element 12 and the data acquisition unit 31 of the central processing module 30. The amplifier 40 is used to amplify the temperature change signal or used with the central processing module 30 and the state switching module 20 The state of the thermoelectric element 12 is controlled. The amplifier 40 has an input 41 and an output 42.

Please refer to FIG. 7 to FIG. 9, the first end 121 of the thermoelectric element 12 is coupled to the reference power terminal 1, the second end 122 of the thermoelectric element 12 is coupled to the state switching module 20, and the input end 41 of the amplifier 40 is connected to The thermoelectric element 12 is coupled, and the output 42 of the amplifier 40 and the central processing module 30 are coupled to the filter 2 and the analog-to-digital converter 3; in the embodiment of the present invention, the filter 2 is a low-pass filter (RC Filter) .

When the digital voltage of the control signal given to the state switching module 20 by the central processing module 30 is 0, the first end 121 and the second end 122 of the thermoelectric element 12 respectively receive different voltages, and the voltage difference causes the thermoelectric element 12 to heat up In the state, the control signal determines the length of time during which the thermoelectric element 12 is in the heating state according to the heating time Th set by the time control unit 32.

When the digital voltage of the control signal given to the state switching module 20 by the central processing module 30 is 1, and there is no voltage difference between the first end 121 and the second end 122 of the thermoelectric element 12, the thermoelectric element 12 will be detected. In the detection state, the control signal of the central processing module 30 in the detection state determines the length of the period in which the thermoelectric element 12 is in the detection state according to the steady-state time Ts and the reading time Tm set by the time control unit 32.

Then, the control signal will correspond to the reading time Tm, and the generated temperature change signal will be input to the amplifier 40, which is amplified by the amplifier 40, and then the amplified temperature change signal is transmitted from the output terminal 42 of the amplifier 40 to the filter The filter 2 performs noise filtering on the temperature change signal by the filter 2 and processes it into the central processing module 30 through the analog-to-digital converter 3. The data acquisition unit 31 of the central processing module 30 processes and analyzes to generate temperature change information.

10 is a schematic diagram of an embodiment of the circuit of the present invention. The input terminal 41 of the amplifier 40 has a positive phase connection terminal 411 and a negative phase connection terminal 412 respectively. The positive phase connection terminal 411 is coupled to the second end 122 of the thermoelectric element 12 The negative-phase connection terminal 412 is coupled to the state switching module 20, and the first terminal 121 of the thermoelectric element 12 is coupled to the reference power terminal 1.

When the digital voltage of the control signal given by the central processing module 30 to the state switching module 20 is 0, the first end 121 and the second end 122 of the thermoelectric element 12 respectively receive different voltages, and the amplifier 40 does not generate a virtual short circuit, and The thermoelectric element 12 is heated by the voltage difference.

When the digital voltage of the control signal given by the central processing module 30 to the state switching module 20 is 1, there is no voltage difference between the first end 121 and the second end 122 of the thermoelectric element 12, and the amplifier 40 will generate a virtual short circuit. The thermoelectric element 12 will be in the detection state, the amplifier 40 can receive the temperature change signal generated by the thermoelectric element 12, and the amplifier 40 performs the amplification processing, and the filter 2 filters the temperature change signal for noise, and the analog digital conversion The processor 3 enters the central processing module 30, and the data acquisition unit 31 of the central processing module 30 processes and analyzes to generate temperature change information.

It should be particularly noted that in the present invention, after the data acquisition unit 31 processes and analyzes the temperature change information, the control signal of the central processing module 30 can directly control the thermoelectric element 12 to return to the heating state, as shown in FIGS. 5 and 7; Or after the data acquisition unit 31 processes and analyzes the temperature change information, the control signal of the central processing module 30 first controls the thermoelectric element 12 in a delayed state, and after the delay state makes the thermoelectric element 12 in a stable state, then controls the thermoelectric element 12 To the heating state, as shown in Figure 6 and Figure 8.

In summary, the present invention has the following effects:

1. The gas convection heat conduction measurement system 100 of the present invention controls the thermoelectric element 12 to heat or detect the state through the state switching module 20, and then performs detection by heating in a short time; thereby, ensuring the accuracy of detection .

2. The gas convective heat conduction measurement system 100 of the present invention does not require an additional heater, and only needs to control the thermoelectric element 12 to heat or detect the state through the state switching module 20; thereby, the low system cost of the present invention can be effectively reduced, and Reduce wafer area and increase manufacturing yield.

3. The amplifier 40 of the present invention can be used as a signal amplification process and has a dual function of controlling the state of the thermoelectric element 12.

4. The gas convection heat conduction measurement system 100 of the present invention can control the thermoelectric element 12 to be in a delayed state after detecting the side state; thereby, it can avoid the thermoelectric element 12 being connected to the heating state under the unstable state, thus affecting the detection accuracy, Furthermore, the signal-to-noise ratio detected by the invention is improved.

The above-mentioned embodiments are only used to illustrate the present invention, not to limit the scope of the present invention. Any modifications or changes that do not violate the spirit of the present invention are within the scope of the invention to be protected.

1: Reference power terminal 131: Etching hole 2: filter 132: Piercing 3: Analog to digital converter 20: State switching module 100: Gas convection heat conduction measurement system 30: central processing module 10: Microcomputer inductive measurement module 31: Data extraction unit 11: substrate 32: Time control unit 12: Thermoelectric element 40: amplifier 121: The first end 41: input 122: second end 411: Normal phase connection 123: Thermoelectric unit 412: Negative phase connection 123a: the first side 42: output 123b: second side Th: heating time 123c: first side Ts: steady state time 123d: second side Tm: read time 13: insulating member To: delay time

FIG. 1 is a schematic perspective view of the present invention. Fig. 2 is a top view of Fig. 1. 3 is a schematic cross-sectional view of the present invention. 4 is a system architecture diagram of the present invention. 5 is a schematic diagram (1) of the control flow of the time control unit of the present invention. 6 is a schematic diagram (2) of the control flow of the time control unit of the present invention. 7 is a schematic diagram of the digital and analog voltage changes of the control signal of the present invention (1). 8 is a schematic diagram (2) of the digital and analog voltage changes of the control signal of the present invention. 9 is a schematic diagram of the circuit architecture of the present invention. 10 is a schematic diagram of an embodiment of the circuit of the present invention.

1: Reference power terminal

2: filter

3: Analog to digital converter

12: Thermoelectric element

121: The first end

122: second end

20: State switching module

30: central processing module

40: amplifier

41: input

42: output

Claims (11)

A gas convection heat conduction measurement system, comprising: a microcomputer inductive measurement module, which has a substrate and a thermoelectric element provided on the substrate; a state switching module, which is coupled to the thermoelectric element; and a center A processing module, which is coupled to the thermoelectric element and the state switching module, the central processing module outputs a control signal to the state switching module, and the state switching module controls the thermoelectric element to heat according to the control signal State or a detection state, in the heating state, the thermoelectric element is heated; in the detection state, the thermoelectric element detects gas thermal conduction to generate a temperature change signal, the central processing module receives The temperature change signal. The gas convection heat conduction measurement system according to claim 1, wherein the central processing module has a data acquisition unit that receives and processes the temperature change signal to generate a temperature change information. The gas convection heat conduction measurement system as described in claim 2 further has an amplifier coupled between the thermoelectric element and the data acquisition unit. The amplifier is used to amplify the temperature change signal. The gas convection heat conduction measurement system according to claim 3, wherein the amplifier has a positive phase connection end and a negative phase connection end, the thermoelectric element has a first end and a second end, the positive phase connection end It is coupled to the second terminal, the negative phase connection terminal is coupled to the state switching module, and the first terminal is coupled to a reference power terminal. The gas convection heat conduction measurement system according to claim 1, wherein the microcomputer inductive measurement module has an insulating member disposed between the substrate and the thermoelectric element. The gas convection heat conduction measurement system according to claim 5, wherein the thermoelectric element has a plurality of thermoelectric units, and each of the thermoelectric units is spaced around the insulating member. The gas convection heat conduction measurement system according to claim 6, wherein the insulating member covers each of the thermoelectric units, and an etching hole is provided between two adjacent thermoelectric units. The gas convection heat conduction measurement system according to claim 6, wherein each of the thermoelectric units has a fan shape. The gas convection heat conduction measurement system according to claim 1, wherein the state switching module further has a delay state, and the delay state is after the detection state. The gas convection heat conduction measurement system according to claim 9, wherein the central processing module has a time control unit, the time control unit is provided with a heating time, a steady state time and a reading time, the control signal is based on The heating time determines the length of the period in which the thermoelectric element is in the heating state; the control signal determines the length of the period in which the thermoelectric element is in the detection state according to the steady-state time and the reading time. The gas convection heat conduction measurement system according to claim 10, wherein the time control unit has a delay time corresponding to the delay state and later than the reading time, and the control signal determines the delay time according to the delay time The length of time that the thermoelectric element is in this delayed state.

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