CN114279626A - Gas vacuum degree detection method and system based on thin film capacitor - Google Patents
Gas vacuum degree detection method and system based on thin film capacitor Download PDFInfo
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Abstract
The invention provides a gas vacuum degree detection method and a system based on a film capacitor, comprising the following steps: respectively inputting preset excitation signals into a detection circuit with a thin-film capacitor and a reference circuit with a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals; obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit; resolving the detection signal to obtain a gas vacuum degree detection value; wherein the reference capacitor is a capacitor of another kind than a film capacitor. The method is used for solving the defects that the vacuum degree measurement method in the medium-high vacuum range in the prior art is complex in scheme and low in vacuum degree, the accurate detection of the high vacuum degree in the medium-high vacuum range is realized, and the detection method is simple and easy to implement.
Description
Technical Field
The invention belongs to the technical field of detection, and particularly relates to a gas vacuum degree detection method and system based on a film capacitor.
Background
Vacuum measurement technology is widely applied to the fields of semiconductor manufacturing, chemical metallurgy, aerospace and the like, and along with the continuous progress of science and technology, vacuum degree detection technology based on different principles also emerges endlessly, such as: compression type vacuum detection, hot cathode ionization vacuum detection, pirani thermal resistance vacuum detection and the like. Different detection methods are applicable to different vacuum measurement ranges, such as: convection vacuum detection, mercury column vacuum detection, resistance vacuum detection, thermocouple vacuum detection and the like are suitable for the medium-low vacuum range, and ionization vacuum detection and hot cathode magnetic control vacuum detection schemes are suitable for the medium-high vacuum range.
For detection in a medium-high vacuum range, a scheme with relatively high precision is required, but most of the existing schemes for measuring vacuum degrees in the medium-high vacuum range are complex, for example, in a capacitance detection circuit of a thin film capacitance vacuum gauge based on a diode bridge, the principle is shown in fig. 1, namely, the diode bridge circuit is adopted as the detection circuit, specifically, a detection capacitor and a measurement capacitor in the vacuum gauge are directly connected into the circuit, a direct current component of an output signal after being excited by a sine alternating current signal is in direct proportion to a difference value of the two capacitors, and a final output signal can be obtained through processing such as filtering, amplification, zero adjustment and the like. The diode bridge circuit shown in fig. 2 is a core part of the capacitance detection method, capacitance values of a measurement capacitance and a reference capacitance in the figure are in the pF magnitude, and a sine signal enters the diode bridge through a coupling capacitance and then outputs a detection signal, as can be seen from fig. 1 and fig. 2, the detection circuit comprises an oscillation circuit part and is complex to control, and according to experimental data of the detection circuit, the measurement range is only 0.75-7.5Torr, and the vacuum degree is not high.
Disclosure of Invention
The invention provides a gas vacuum degree detection method and system based on a thin-film capacitor, which are used for solving the defects of complex scheme and low vacuum degree of a vacuum degree measurement method in a medium-high vacuum range in the prior art, realizing accurate detection of the high vacuum degree in the medium-high vacuum range, and being simple and easy to implement.
The invention provides a gas vacuum degree detection method based on a film capacitor, which comprises the following steps:
respectively inputting preset excitation signals into a detection circuit with a thin-film capacitor and a reference circuit with a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals;
obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
resolving the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
According to the method for detecting the gas vacuum degree based on the film capacitor, before the preset excitation signal is respectively input into the detection circuit containing the film capacitor and the reference circuit containing the reference capacitor, the method further comprises the following steps:
the temperature in the detection space is monitored in real time, and when the monitored temperature exceeds a preset temperature range, the temperature in the detection space is adjusted, so that the temperature in the detection space is always maintained in the temperature range.
According to the gas vacuum degree detection method based on the film capacitor, the preset excitation signals are respectively input into the detection circuit containing the film capacitor and the reference circuit containing the reference capacitor, and the method specifically comprises the following steps:
and respectively inputting the carrier with adjustable amplitude and frequency as the excitation signal into a detection circuit consisting of a film capacitor and a first amplifying circuit and a reference circuit consisting of a reference capacitor and a second amplifying circuit.
According to the method for detecting the vacuum degree of the gas based on the thin film capacitor, the carrier wave with adjustable amplitude and frequency is used as the excitation signal and is respectively input into the detection circuit formed by the thin film capacitor and the first amplifying circuit, and the reference circuit formed by the reference capacitor and the second amplifying circuit, and the method specifically comprises the following steps:
the carrier with adjustable amplitude and frequency is used as the excitation signal and is respectively input into a detection circuit consisting of a film capacitor and a first amplifying circuit containing a first feedback capacitor, and a reference circuit consisting of a reference capacitor and a second amplifying circuit containing a second feedback capacitor;
wherein an initial capacitance value of the thin film capacitor and a capacitance value of the reference capacitor are equal; the first and second feedback capacitors are of the same kind having a capacitance equal to that of the reference capacitor.
According to the method for detecting the degree of vacuum of the gas based on the thin film capacitor, the detection signal is obtained according to the output signal of the detection circuit and the output signal of the reference circuit, and the method specifically comprises the following steps:
the output signal of the detection circuit and the output signal of the reference circuit are used as the input of a differential amplification circuit, and the differential amplification circuit obtains a detection signal expressed in the form of a difference amplification value of the output signals of the detection circuit and the reference circuit.
The invention also provides a gas vacuum degree detection system based on the film capacitor, which comprises:
the signal acquisition module is used for respectively inputting preset excitation signals into a detection circuit containing a thin-film capacitor and a reference circuit containing a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals;
the signal processing module is used for obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
the signal resolving module is used for resolving the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
The gas vacuum degree detection system based on the film capacitor further comprises:
and the temperature control module is used for monitoring the temperature in the detection space in real time and adjusting the temperature in the detection space when the monitored temperature exceeds a preset temperature range so as to maintain the temperature in the detection space in the temperature range all the time.
According to the gas vacuum degree detection system based on the film capacitor, the signal processing module is a differential amplification module;
the differential amplification module is used for taking the output signal of the detection circuit and the output signal of the reference circuit as input and outputting a difference amplification value of the output signal of the detection circuit and the output signal of the reference circuit.
The gas vacuum degree detection system based on the film capacitor further comprises:
a digital-to-analog conversion module for generating a carrier as the excitation signal through digital-to-analog conversion;
and the adjusting module is used for adjusting the amplitude and the frequency of the carrier wave to meet the input requirements of the detection circuit and the reference circuit.
The gas vacuum degree detection system based on the film capacitor further comprises:
and the analog-to-digital conversion module is used for converting the difference amplification value output by the differential amplification module from an analog signal to a digital signal and then inputting the digital signal to the signal calculation module for calculation.
The invention provides a method and a system for detecting gas vacuum degree based on a film capacitor, which respectively input preset excitation signals into a detection circuit containing the film capacitor and a reference circuit containing a reference capacitor, utilize the characteristic that the film capacitor can deform along with the air pressure to change the capacitance value of the film capacitor, so that when the air pressure in a detection space changes, the signal output by the detection circuit can change under the action of the excitation signals, but the output signal of the reference circuit where the reference capacitor of the film capacitor is not located does not change because of the change of the air pressure, further take the output signal of the reference circuit as a comparison reference, can conveniently obtain detection signals related to the capacitance value change quantity of the film capacitor, namely the gas vacuum degree in the detection space changes, and then obtain a gas vacuum degree detection value by resolving the detection signals, the detection method is simple and easy to implement.
The preset excitation signals are respectively input into the detection circuit and the reference circuit, so that the detection circuit and the reference circuit take the same excitation signal as input, the influence of noise and offset on a detection result caused by different input signals is avoided, and the detection accuracy is improved.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a block diagram of a detection principle of a capacitance detection circuit of a prior art diode bridge-based thin film capacitance vacuum gauge;
FIG. 2 is a diode bridge circuit of the capacitance detection circuit of the diode bridge based thin film capacitance vacuum gauge shown in FIG. 1;
FIG. 3 is a schematic flow chart of a method for detecting a gas vacuum degree based on a film capacitor according to the present invention;
FIG. 4 is a schematic diagram of capacitance detection of a method for detecting gas vacuum degree based on a thin film capacitor according to the present invention;
FIG. 5 is a circuit diagram of a capacitance detection circuit provided by the present invention;
FIG. 6 is a diagram showing the detection effect of the detection of the degree of vacuum of gas by using the circuit diagram of the capacitance detection circuit provided by the present invention;
FIG. 7 is a circuit diagram of the capacitance detection circuit diagram of FIG. 5 modified with a two-carrier input;
FIG. 8 is a graph of air pressure sensing stability test results obtained using the capacitance sensing circuit of FIG. 5;
FIG. 9 is a graph of air pressure sensing stability test results obtained using the capacitance sensing circuit of FIG. 7;
FIG. 10 is a schematic structural diagram of a gas vacuum degree detection system based on a film capacitor provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A method for detecting a degree of vacuum of a gas based on a film capacitor according to the present invention will be described with reference to fig. 3 to 9, the method comprising the steps of:
101. respectively inputting preset excitation signals into a detection circuit with a thin-film capacitor and a reference circuit with a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals;
102. obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
103. resolving the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
The film capacitor is a cylindrical capacitor formed by winding a metal foil as an electrode and a plastic film such as polyethylene, polypropylene, polystyrene or polycarbonate after being overlapped from two ends, and the film capacitor has the advantages of no polarity, high insulation impedance, wide frequency response, small dielectric loss and the like, and has the characteristic of changing the capacitance value along with the deformation of air pressure, namely, when the vacuum degree of a gas to be detected changes, the gap of the film capacitor changes, and the capacitance value also changes.
Specifically, by inputting preset excitation signals into a detection circuit with a film capacitor and a reference circuit with a reference capacitor respectively, when the vacuum degree in a detection space changes, namely air pressure changes, a signal output by the detection circuit under the action of the excitation signals changes due to the change of the capacitance value of the film capacitor, but the capacitor in the reference circuit is not the film capacitor, so that the output signal does not change, and further, by taking the output signal of the reference circuit as a comparison reference, a detection signal related to the capacitance value change quantity of the film capacitor, namely the change of the gas vacuum degree in the detection space can be conveniently obtained, and then, the detection signal is resolved to obtain a gas vacuum degree detection value.
In the detection method, only after the excitation signal is set, the excitation signal is input into the detection circuit comprising the film capacitor and the reference circuit comprising the reference capacitor, and then the output signal is resolved, so that the vacuum degree change of the detection space can be obtained.
More specifically, the input ends of the detection circuit and the reference circuit obtain an excitation signal, that is, the noise and the offset for the detection circuit and the reference circuit are the same, so that the influence of the noise and the offset on the detection accuracy caused by different input signals is effectively avoided.
Furthermore, the temperature has a certain influence on the parameters of the film capacitor, the detection circuit and the reference circuit, so that the accuracy of detecting the vacuum degree in the detection space can be directly influenced by the change of the temperature.
Based on this, in an embodiment of the present invention, before inputting the preset excitation signal to the detection circuit including the film capacitor and the reference circuit including the reference capacitor, respectively, the method further includes:
the temperature in the detection space is monitored in real time, and when the monitored temperature exceeds a preset temperature range, the temperature in the detection space is adjusted, so that the temperature in the detection space is always maintained in the temperature range.
It should be noted that, by monitoring the temperature in the detection space in real time and adjusting the temperature in real time, the temperature in the detection space is always kept within the preset temperature range, it can be understood that the temperature is always kept at a fixed value, which is the most ideal detection state, however, the temperature is always fixed in the use application, which is basically impossible to achieve, so in the above embodiment, the temperature range is set to be relatively small, the temperature in the detection space is kept at a fixed value as much as possible, thereby effectively eliminating the influence of the temperature on the film capacitor and other circuit parameters, and improving the detection accuracy.
In the detection of the gas vacuum degree in the medium-high vacuum range, the absolute variation of the detected gas vacuum degree is often small, so that the variation of the capacitance value of the film capacitor caused by the variation of the gas pressure is small, and the accurate detection of the vacuum degree is relatively difficult by simply calculating the small variation of the capacitance value of the film capacitor. It will also be appreciated that the value of the capacitance of the capacitor is a frequency dependent quantity, and therefore there should be some consideration of the frequency of the carrier when the circuit contains a capacitor.
Based on this, in another embodiment of the present invention, a carrier wave whose amplitude and frequency are adjustable is inputted as the excitation signal to a detection circuit composed of a thin film capacitor and a first amplification circuit, and a reference circuit composed of a reference capacitor and a second amplification circuit, respectively.
The first amplifier circuit and the second amplifier circuit are identical amplifier circuits, so that influence on output signals of the detection circuit and the reference circuit due to different signal amplification is avoided.
Furthermore, the adjustable amplitude mainly prevents the output saturation of the post-stage signal amplification circuit, and the adjustable frequency mainly finds the optimal frequency of the circuit operation, for example, when a plurality of detection circuits work together, a beat frequency phenomenon may occur, and the carrier frequency of each detection circuit is finely adjusted, so that the detection interference caused by the beat frequency can be eliminated.
Further, in order to further ensure the accuracy of the detection result, in another embodiment of the present invention, a feedback capacitor is applied in the amplifying circuit, that is:
the carrier with adjustable amplitude and frequency is used as the excitation signal and is respectively input into a detection circuit consisting of a film capacitor and a first amplifying circuit containing a first feedback capacitor, and a reference circuit consisting of a reference capacitor and a second amplifying circuit containing a second feedback capacitor;
wherein an initial capacitance value of the thin film capacitor and a capacitance value of the reference capacitor are equal; the first and second feedback capacitors are of the same kind having a capacitance equal to that of the reference capacitor.
Further, when the initial capacitance of the film capacitor is different from the capacitance of the reference capacitor, there are inconveniences in practical application, such as: and when the gas vacuum degree is not changed, the output of the later stage is saturated, the output zero position is large, and the like. Therefore, it is most convenient to select a reference capacitor having the same initial capacitance value as the thin film capacitor. The first feedback capacitor and the second feedback capacitor are respectively used for amplifying the output signals of the film capacitor and the reference capacitor, so that the capacitance values are equal to or similar to that of the reference capacitor, namely, the first feedback capacitor and the second feedback capacitor are capacitors with the same capacitance values, and the variable quantity of the film capacitor can be more conveniently calculated when the vacuum degree of the detection space is changed.
Further, the reference circuit is used to use its output signal as a reference for the output signal of the detection circuit, so that when the difference between the output signal of the detection circuit and the output signal of the reference circuit can directly reflect the variation of the capacitance value of the film capacitor in the detection circuit, i.e., the variation of the degree of vacuum of the gas, in another embodiment of the present invention, the output signal of the detection circuit and the output signal of the reference circuit are used as the input of a differential amplification circuit, and the detection signal represented in the form of the amplified value of the difference between the output signals of the detection circuit and the reference circuit is obtained by the differential amplification circuit.
It should be noted that, as shown in fig. 4, a carrier 1 is used as an input of the first amplifying circuit 2 and the second amplifying circuit 3, the first amplifying circuit 2 and the second amplifying circuit 3 respectively form an amplifying circuit with the film capacitor 4 and the reference capacitor 5, then output signals of the first amplifying circuit 2 and the second amplifying circuit 3 respectively serve as input signals of the differential amplifying circuit 6, and an output signal of the differential amplifying circuit 6 is a signal related to a variation of the film capacitor 4, so that a variation of a capacitance value of the film capacitor 4, that is, a variation of a gas vacuum degree, can be represented by an output signal of the differential amplifying circuit. Through the introduction of the first amplifying circuit 2, the second amplifying circuit 3 and the differential amplifying circuit 6, the variation of the capacitance value of the film capacitor 4 caused by the variation of the gas vacuum degree is amplified, the further calculation is convenient, the same carrier 1 is adopted as the input of the first amplifying circuit 2 and the second amplifying circuit 3, when the differential amplifying circuit 6 is utilized for calculating the difference value, the noise and the drift of the output signals of the detection circuit and the reference circuit can be mutually offset, and the noise and the drift brought by the carrier are further reduced.
Specifically, to selectThe first amplifying circuit and the second amplifying circuit formed by the amplifier are taken as an example, after the first feedback capacitor and the second feedback capacitor are introduced, the capacitance detection circuit applied by the gas vacuum degree detection method based on the film capacitor is shown in fig. 5, namely, a carrier wave is connected to the non-inverting input end of the amplifier, and the reference capacitor C is connected to the non-inverting input end of the amplifierrefAnd a film capacitor CxConnected to the inverting input terminal of the amplifier, respectively, and matched with the reference capacitor C at the output terminal and the inverting input terminal of the amplifierrefAnd a film capacitor CxFeedback capacitor C with equal or similar capacitancefAnd then the output end of the amplifier is connected with a differential amplification circuit, and the output of the differential amplification circuit is the variable quantity of the film capacitor, namely the variable quantity of the gas vacuum degree. Under the condition, the amplitude out of the output signal of the differential amplifier circuit and the variation Δ C of the film capacitor can be derivedxThe relationship of (a) is shown as follows:
wherein, VinIs the amplitude of the input carrier signal and Gain is the Gain of the differential amplifier circuit.
More specifically, a sinusoidal carrier signal with a frequency of 10kHz and an amplitude of 5V is used as an input carrier of the capacitor detection circuit shown in fig. 5, and the output of the differential amplification circuit is resolved to obtain a gas vacuum degree detection effect shown in fig. 6, so that the gas vacuum degree detection method based on the thin film capacitor according to the embodiment of the present invention has a gas vacuum degree measurement range of 10e-4 to 0.1Torr, that is, a high vacuum degree detection from almost absolute vacuum to 0.1Torr is achieved, and the linearity of the detection result is high.
Further, two paths of carriers are arranged, a carrier 1 and a carrier 2 are respectively input into an amplifier connected with a film capacitor and a reference capacitor, other parts are the same as the capacitor detection circuit in fig. 5, a circuit diagram is shown in fig. 7, the output of the differential amplification circuit in fig. 5 and fig. 7 is respectively solved, and the stability test result of the air pressure under the vacuum condition is shown in fig. 8 and fig. 9.
The following describes a gas vacuum degree detection system based on a film capacitor provided by the present invention with reference to fig. 10, and a gas vacuum degree detection system based on a film capacitor described below and a gas vacuum degree detection method based on a film capacitor described above can be referred to correspondingly.
As shown in fig. 10, the present invention provides a gas vacuum detecting system based on a film capacitor, including: a signal acquisition module 110, a signal processing module 120 and a signal resolving module 130; wherein the content of the first and second substances,
the signal obtaining module 110 is configured to input a preset excitation signal to a detection circuit including a thin film capacitor and a reference circuit including a reference capacitor, and obtain output signals from the detection circuit and the reference circuit under the action of the excitation signal;
the signal processing module 120 is configured to obtain a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
the signal calculating module 130 is configured to calculate the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
The invention provides a gas vacuum degree detection system based on a film capacitor, which is characterized in that a preset excitation signal is respectively input into a detection circuit containing the film capacitor and a reference circuit containing a reference capacitor, the characteristic that the film capacitor can deform along with the air pressure to change the capacitance value of the film capacitor is utilized, so that when the air pressure in a detection space changes, a signal output by the detection circuit can change under the action of the excitation signal, the output signal of the reference circuit where the reference capacitor of the film capacitor is not located does not change due to the change of the air pressure, and further the output signal of the reference circuit is used as a comparison reference, a detection signal related to the capacitance value change quantity of the film capacitor, namely the gas vacuum degree in the detection space changes, and then the detection signal is resolved to obtain a gas vacuum degree detection value, the detection method is simple and easy to implement.
The preset excitation signals are respectively input into the detection circuit and the reference circuit, so that the detection circuit and the reference circuit take the same excitation signal as input, the influence of noise and offset on a detection result caused by different input signals is avoided, and the detection accuracy is improved.
Optionally, the detection circuit is composed of a thin film capacitor and a first amplifying circuit; the reference circuit is composed of a reference capacitor and a second amplifying circuit.
Further optionally, the first amplifying circuit includes a first feedback capacitor, the second amplifying circuit includes a second feedback capacitor, and an initial capacitance value of the thin film capacitor is equal to a capacitance value of the reference capacitor; the first and second feedback capacitors are of the same kind having a capacitance equal to that of the reference capacitor.
In a preferred embodiment, the gas vacuum degree detection system based on the film capacitor further includes a temperature control module 130.
The temperature control module 130 is configured to monitor a temperature in the detection space in real time, and adjust the temperature in the detection space when the monitored temperature exceeds a preset temperature range, so that the temperature in the detection space is always maintained in the temperature range.
It should be noted that the temperature control module includes a temperature measurement portion and a temperature change portion, and its main function is to keep the temperature in the system as stable as possible at a certain fixed value, so as to eliminate the influence of the temperature on the film capacitor and other circuit parameters.
In another preferred embodiment, the signal processing module 120 is a differential amplifying module;
the differential amplification module is used for taking the output signal of the detection circuit and the output signal of the reference circuit as input and outputting a difference amplification value of the output signal of the detection circuit and the output signal of the reference circuit.
The differential amplification module, the detection circuit and the reference circuit together form a capacitance detection circuit of the gas vacuum degree detection system based on the film capacitor, and a carrier wave is input into the capacitance detection circuit, and an output detection signal is resolved by the signal resolving module, so that a gas vacuum degree detection value can be obtained.
In another preferred scheme, the gas vacuum degree detection system based on the thin film capacitor further comprises a digital-to-analog conversion module and an adjustment module; wherein the content of the first and second substances,
the digital-to-analog conversion module is used for generating a carrier serving as the excitation signal through digital-to-analog conversion;
the adjusting module is used for adjusting the amplitude and the frequency of the carrier wave to meet the input requirements of the detecting circuit and the reference circuit.
The analog-to-digital conversion module is used for converting the difference amplification value output by the differential amplification module from an analog signal to a digital signal and then inputting the digital signal to the signal calculation module for calculation.
It should be noted that the adjusting module for adjusting the amplitude and the frequency of the carrier to meet the input requirements of the detection circuit and the reference circuit may be an independent module having this function, or may also be a function of the signal calculating module, and then the amplitude and the frequency of the carrier are adjusted by the signal calculating module.
In another preferred scheme, the gas vacuum degree detection system based on the film capacitor further comprises an analog-to-digital conversion module;
the analog-to-digital conversion module is used for converting the difference amplification value output by the differential amplification module from an analog signal to a digital signal and then inputting the digital signal to the signal calculation module for calculation.
It should be noted that, based on the advantages of the non-polarity, high insulation resistance, wide frequency response and small dielectric loss of the film capacitor, the film capacitor is mostly used in an analog circuit, and therefore, the analog-to-digital conversion module is used to sample the detection amplification signal, so that the signal calculation module calculates the gas vacuum value according to the amplified detection signal.
It can be understood that the gas vacuum degree detection system based on the film capacitor further comprises a power supply module capable of supplying power to each module, and meanwhile, in order to enrich the functions of the system, a communication module, a parameter adjusting module and an indicating module which are respectively connected with the signal resolving module can be configured; therefore, the signal resolving module can realize communication with an external system under a specified protocol through the communication module, can realize the function of adjusting the parameters of the system by adapting the system to a new application environment through the parameter adjusting module, and can realize the display of the state of the system according to the command of the signal resolving module through the indicating module.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A gas vacuum degree detection method based on a film capacitor is characterized by comprising the following steps:
respectively inputting preset excitation signals into a detection circuit with a thin-film capacitor and a reference circuit with a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals;
obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
resolving the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
2. The film capacitor-based gas vacuum degree detection method according to claim 1, wherein before inputting the preset excitation signal to the detection circuit including the film capacitor and the reference circuit including the reference capacitor, respectively, the method further comprises:
the temperature in the detection space is monitored in real time, and when the monitored temperature exceeds a preset temperature range, the temperature in the detection space is adjusted, so that the temperature in the detection space is always maintained in the temperature range.
3. The method for detecting the degree of vacuum of a gas based on a film capacitor as claimed in claim 2, wherein the step of inputting the preset excitation signal into the detection circuit comprising the film capacitor and the reference circuit comprising the reference capacitor respectively comprises:
and respectively inputting the carrier with adjustable amplitude and frequency as the excitation signal into a detection circuit consisting of a film capacitor and a first amplifying circuit and a reference circuit consisting of a reference capacitor and a second amplifying circuit.
4. The film capacitor-based gas vacuum degree detection method according to claim 3, wherein the carrier wave with adjustable amplitude and frequency is respectively input into a detection circuit composed of the film capacitor and a first amplifying circuit and a reference circuit composed of a reference capacitor and a second amplifying circuit as the excitation signal, and specifically comprises:
the carrier with adjustable amplitude and frequency is used as the excitation signal and is respectively input into a detection circuit consisting of a film capacitor and a first amplifying circuit containing a first feedback capacitor, and a reference circuit consisting of a reference capacitor and a second amplifying circuit containing a second feedback capacitor;
wherein an initial capacitance value of the thin film capacitor and a capacitance value of the reference capacitor are equal; the first and second feedback capacitors are of the same kind having a capacitance equal to that of the reference capacitor.
5. The method for detecting the degree of vacuum of a gas based on a film capacitor according to claim 4, wherein the obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit specifically comprises:
the output signal of the detection circuit and the output signal of the reference circuit are used as the input of a differential amplification circuit, and the differential amplification circuit obtains a detection signal expressed in the form of a difference amplification value of the output signals of the detection circuit and the reference circuit.
6. A gas vacuum detection system based on a film capacitor is characterized by comprising:
the signal acquisition module is used for respectively inputting preset excitation signals into a detection circuit containing a thin-film capacitor and a reference circuit containing a reference capacitor, and respectively obtaining output signals by the detection circuit and the reference circuit under the action of the excitation signals;
the signal processing module is used for obtaining a detection signal according to the output signal of the detection circuit and the output signal of the reference circuit;
the signal resolving module is used for resolving the detection signal to obtain a gas vacuum degree detection value;
wherein the reference capacitor is a capacitor of another kind than a film capacitor.
7. The film capacitor-based gas vacuum detection system of claim 6, further comprising:
and the temperature control module is used for monitoring the temperature in the detection space in real time and adjusting the temperature in the detection space when the monitored temperature exceeds a preset temperature range so as to maintain the temperature in the detection space in the temperature range all the time.
8. The film capacitor-based gas vacuum detection system of claim 7, wherein the signal processing module is a differential amplification module;
the differential amplification module is used for taking the output signal of the detection circuit and the output signal of the reference circuit as input and outputting a difference amplification value of the output signal of the detection circuit and the output signal of the reference circuit.
9. The film capacitor-based gas vacuum detection system of claim 8, further comprising:
a digital-to-analog conversion module for generating a carrier as the excitation signal through digital-to-analog conversion;
and the adjusting module is used for adjusting the amplitude and the frequency of the carrier wave to meet the input requirements of the detection circuit and the reference circuit.
10. The film capacitor based gas vacuum detection system of claim 9, further comprising:
and the analog-to-digital conversion module is used for converting the difference amplification value output by the differential amplification module from an analog signal to a digital signal and then inputting the digital signal to the signal calculation module for calculation.
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Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4322977A (en) * | 1980-05-27 | 1982-04-06 | The Bendix Corporation | Pressure measuring system |
| US4457179A (en) * | 1981-03-16 | 1984-07-03 | The Bendix Corporation | Differential pressure measuring system |
| US4644798A (en) * | 1984-09-06 | 1987-02-24 | Yokogawa Hokushin Electric Corporation | Capacitive type converter device |
| US5291534A (en) * | 1991-06-22 | 1994-03-01 | Toyoda Koki Kabushiki Kaisha | Capacitive sensing device |
| JPH10132684A (en) * | 1996-10-25 | 1998-05-22 | Hitachi Ltd | Semiconductor pressure sensor |
| US6377056B1 (en) * | 1998-08-26 | 2002-04-23 | Hitachi, Ltd. | Electrostatic capacitance type dynamical quantity sensor |
| US6631645B1 (en) * | 2000-02-22 | 2003-10-14 | Hitachi, Ltd. | Semiconductor pressure sensor utilizing capacitance change |
| CN1535372A (en) * | 2001-07-20 | 2004-10-06 | ������˹�ͺ�ɪ�����Ϲ�˾ | Circuit configuration for capacitive sensor |
| JP2007078648A (en) * | 2005-09-16 | 2007-03-29 | Matsushita Electric Works Ltd | Sensor device |
| CN1961204A (en) * | 2004-05-19 | 2007-05-09 | 株式会社山武 | Capacitive pressure sensor |
| CN101360451A (en) * | 2005-12-23 | 2009-02-04 | 凯维力科公司 | Multiple function stable sensor circuitry |
| CN104062327A (en) * | 2014-07-10 | 2014-09-24 | 熊刚 | Capacitive sensor complementary stimulation and linear detection scheme for oil detection |
| CN104142206A (en) * | 2013-05-07 | 2014-11-12 | 上海丽恒光微电子科技有限公司 | MEMS capacitive pressure sensor and manufacturing method thereof |
| DE102020122128B3 (en) * | 2020-08-25 | 2021-11-04 | Ifm Electronic Gmbh | Method for monitoring the function of a capacitive pressure measuring cell |
-
2021
- 2021-12-06 CN CN202111481431.0A patent/CN114279626A/en active Pending
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4322977A (en) * | 1980-05-27 | 1982-04-06 | The Bendix Corporation | Pressure measuring system |
| US4457179A (en) * | 1981-03-16 | 1984-07-03 | The Bendix Corporation | Differential pressure measuring system |
| US4644798A (en) * | 1984-09-06 | 1987-02-24 | Yokogawa Hokushin Electric Corporation | Capacitive type converter device |
| US5291534A (en) * | 1991-06-22 | 1994-03-01 | Toyoda Koki Kabushiki Kaisha | Capacitive sensing device |
| JPH10132684A (en) * | 1996-10-25 | 1998-05-22 | Hitachi Ltd | Semiconductor pressure sensor |
| US6377056B1 (en) * | 1998-08-26 | 2002-04-23 | Hitachi, Ltd. | Electrostatic capacitance type dynamical quantity sensor |
| US6631645B1 (en) * | 2000-02-22 | 2003-10-14 | Hitachi, Ltd. | Semiconductor pressure sensor utilizing capacitance change |
| CN1535372A (en) * | 2001-07-20 | 2004-10-06 | ������˹�ͺ�ɪ�����Ϲ�˾ | Circuit configuration for capacitive sensor |
| CN1961204A (en) * | 2004-05-19 | 2007-05-09 | 株式会社山武 | Capacitive pressure sensor |
| JP2007078648A (en) * | 2005-09-16 | 2007-03-29 | Matsushita Electric Works Ltd | Sensor device |
| CN101360451A (en) * | 2005-12-23 | 2009-02-04 | 凯维力科公司 | Multiple function stable sensor circuitry |
| CN104142206A (en) * | 2013-05-07 | 2014-11-12 | 上海丽恒光微电子科技有限公司 | MEMS capacitive pressure sensor and manufacturing method thereof |
| CN104062327A (en) * | 2014-07-10 | 2014-09-24 | 熊刚 | Capacitive sensor complementary stimulation and linear detection scheme for oil detection |
| DE102020122128B3 (en) * | 2020-08-25 | 2021-11-04 | Ifm Electronic Gmbh | Method for monitoring the function of a capacitive pressure measuring cell |
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