• 专利附录
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    • 专利摘要:
    A pressure gauge (G) includes a first detector (42) for detecting a pressure in a first range, a second detector (41) for detecting a pressure in a second range, and a processing unit (7) for determining the pressure value. based on outputs of the first detector and the second detector. The first and second ranges have an overlap range, the upper limit of the second range is higher than that of the first range, the processing unit determines a correction value based on outputs of the first detector and the second detector when the pressure falls in the overlapping range, and the processing unit determines the pressure value based on the output of the second detector and the correction value, when measuring, using the second detector, the pressure in the second range , higher than that of the first pressure range.
    公开号:CH707338B1
    申请号:CH00541/14
    申请日:2012-09-12
    公开日:2017-10-31
    发明作者:Miyashita Haruzo
    申请人:Canon Anelva Corp；
    IPC主号:
    专利说明:

    TECHNICAL FIELD [0001] The present invention relates to a diaphragm manometer and, more particularly, to a diaphragm manometer with an enlarged pressure measurement range.
    PRIOR ART [0002] In a method for manufacturing electronic components or semiconductor products, the formation and etching of thin layers in a vacuum device are indispensable processes. In this case, it is usual to proceed with the process keeping the internal pressure of the vacuum apparatus constant. As an instrument for measuring the internal pressure of the vacuum apparatus during the process, a diaphragm manometer is often used, which can perform an accurate pressure measurement regardless of the type of gas.
    [0003] FIG. 10 is a view showing an example of the structure of a conventional membrane manometer (the PTL document). A membrane manometer with such a membrane structure has a pressure measurement range of two to four orders of magnitude. This is because the displacement amount of the diaphragm is very small on the low pressure side, and the variation of the diaphragm is not proportional to the pressure on the high pressure side. For this reason, when measuring a wider pressure range with such a diaphragm manometer, it is necessary to perform the pressure measurement by preparing a plurality of diaphragm manometers with different pressure measurement ranges and by individually measuring output voltages by the respective gauges. The membrane manometer disclosed in the PTL 1 includes a correction electrode 10 located at a position out of the center of the membrane electrode 4 (the membrane type depresing detection element) facing it. The capacitance detected by a fixed electrode 5 is corrected by the capacitance detected by the correction electrode 10 in order to reduce the influence of the ambient temperature on the pressure measurement. However, even with the function of this correction electrode, output voltage fluctuations due to ambient temperature fluctuations are unavoidable. For this reason, the diaphragm manometer includes a potentiometer or switch to change the amount of fluctuation.
    On the other hand, as shown in FIG. 11, a membrane manometer with two membrane pressure sensing elements (the PTL 2 document) is known. The membrane manometer disclosed in the PTL 2 document is manufactured by a micro-machining technique using a semiconductor manufacturing process technique. A vacuum sensor chip with an insulating substrate 13 bonded to a silicon substrate 14 (composed of an elastic structure 8 and a rigid structure 11) has a size of about several mm to several tens of mm and a thickness of about 1 mm. The combination of the two diaphragm pressure sensing elements with the different measuring ranges makes it possible to measure a wider pressure range with a single diaphragm manometer. A membrane pressure gauge such as that disclosed in the PTL 2 document is generally configured to correct the capacity influenced by ambient temperature fluctuations for each membrane pressure element by using the correction electrodes provided respectively for the two pressure sensing elements. with membrane.
    List of quotes
    Patent literature [0005] The document PTL 1: US Patent No. 5,515,711 [0006] The document PTL 2: Publication of Japanese Patent No. JP 2001-255 225 Summary of the Invention Technical Problem [0007] However, since the membrane manometer disclosed in the PTL 2 document includes two membrane pressure sensing elements, two pressure values are to be measured in the range where the membrane pressure sensing elements producing the measured values are exchanged. For this reason, some membrane manometers entrust the selection of the measured value to be used in the range where the membrane pressure sensing elements are exchanged to the user. However, in the range where the membrane pressure sensing elements are exchanged, since the measurement accuracy of the membrane pressure sensing element which detects the high pressure range is lower, the error in the measured value is relatively large. To solve such a problem, a method is proposed for performing a calculation by averaging two measured pressures in the exchange or weighting range and producing the value obtained as the measured value. However, an additional improvement is required in the measurement accuracy.
    It is an object of the present invention to provide a diaphragm pressure gauge in which a plurality of membrane pressure sensing elements with different pressure measurement ranges are arranged in a housing, and a good accuracy The measurement range is obtained in the range where the membrane pressure sensing elements are exchanged.
    Solution of the Problem [0009] A membrane manometer according to the present invention comprises a first detector configured to measure the pressure in a first pressure range, a second detector configured to measure the pressure in a second pressure range, each of said first detector and second detector being configured to measure a pressure relative to a reference pressure in a reference pressure chamber, and a processing unit which is configured to determine the measured pressure based on the outputs of said first detector and said second detector, wherein the first pressure range and the second pressure range have an overlap range, wherein the upper limit of the second pressure range is higher than the upper limit of the first pressure range, wherein said processing unit is configured to determine a correction value based on the outputs of said first detector and said second detector when the pressure falls within the overlap range, and wherein said processing unit is configured to determine the pressure value based on the output of said second detector and the correction value, when measuring, using said second detector, the pressure in the second pressure range, which is higher than the upper limit of the first pressure range.
    Advantageous Effects of the Invention [0010] The present invention can provide a diaphragm manometer in which a plurality of membrane pressure sensing elements with different pressure sensing ranges are arranged in a housing, and a good one. Measurement accuracy is achieved in a range where membrane pressure sensing elements are exchanged.
    Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings. It should be noted that the same reference numbers describe identical or similar components throughout the accompanying drawings.
    Brief Description of the Drawings [0012] The accompanying drawings, which are inserted in and constitute a part of the description, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the present invention.
    Fig. 1 is a schematic view of a membrane manometer according to an embodiment of the present invention;
    Fig. 2 is a schematic view of a membrane manometer according to another embodiment of the present invention;
    Fig. 3 is a block diagram showing the systematic configuration of a G-membrane manometer according to an embodiment of the present invention;
    Fig. 4 is a graph showing the relationship between the measured pressures and the digital capacitance values according to the embodiment of the present invention;
    Fig. 5 is a graph showing the relationship between the pressures measured by the membrane manometer and the I / O output signals according to the embodiment of the present invention;
    Fig. 6 is a graph showing the relationship between the measured pressures and the digital capacitance values according to the embodiment of the present invention;
    Fig. 7 is a graph showing the relationship between the pressures measured by the membrane manometer and the digital pressure values according to the embodiment of the present invention;
    Fig. 8 is a flow diagram for the membrane manometer according to the embodiment of the present invention;
    Fig. 9 is a process flow diagram in step S009 in FIG. 8;
    Fig. 10 is a schematic view showing an example of the structure of a conventional membrane manometer; and
    Fig. 11 is a schematic view showing another example of the structure of a conventional membrane manometer.
    Description of Embodiments [0013] FIG. 1 shows a G membrane manometer according to an embodiment of the present invention. The diaphragm manometer G includes, as main constituent elements, a housing 3 whose internal space communicates with a vacuum device 2, a membrane pressure detection unit 18 disposed in the housing 3, and an electrical circuit 7 which detects the value produced by the membrane pressure sensing unit 18 as the pressure value. The housing 3 and an electrical input terminal 9 separate a space from the atmosphere side and a space from the vacuum side of each other. Membrane electrodes 41 and 42 of the membrane pressure sensing unit 18 are arranged in the vacuum side space, and the electrical circuit 7 is arranged in the space on the atmosphere side. The electrical circuit 7 is connected to an external control apparatus or a display apparatus by an electrical output terminal 12. An input / output (I / O) signal terminal 17 outputs, to the outside, information as to whether the electrical output signal of the electrical output terminal 12 is the output measured by one or the other of the fixed electrodes 5a or 5b.
    It is possible to manufacture the membrane pressure sensing unit 18 by, for example, a micro-machining technique using a semiconductor manufacturing process technique. The plurality of membrane electrodes 41 and 42 is formed on a single silicon substrate. Membrane electrodes 41 and 42 have a detection sensitivity with respect to different pressure ranges. The plurality of membrane electrodes 41 and 42 have different surfaces in order to have different pressure detection ranges. The fixed electrodes 5b and 5a are arranged on an insulating substrate 13 so as to face the membrane electrodes 41 and 42, respectively. The pressure gauge detects the capacity-based pressure between the fixed electrodes 5b and 5a and the membrane electrodes 41 and 42. The fixed electrode 5a and the membrane electrode 42 constitute a membrane pressure sensing element (the low pressure side or the first detector). The fixed electrode 5b and the membrane electrode 41 constitute the other membrane pressure sensing element (the high pressure range detector or the second detector).
    The membrane electrode 42 operating in the frame of the low pressure side detector (the first detector) has a high sensitivity in the low pressure range (the first pressure range). The membrane electrode 41 operating in the context of the high pressure range detector (the second detector) has a high sensitivity in the high pressure range (the second pressure range). Although described later, in this embodiment, the range in which the low pressure side detector produces the pressure measurement results is 0.01 Pa to 100 Pa, and the range in which the high pressure range detector produced the pressure measurement results is 100 Pa to 100 000 Pa. It should be noted, however, that the range in which the detector at the low pressure side and the high pressure range detector can perform the pressure measurement (the first and second pressure range) is wider than the range in which each detector can produce pressure measurement results. The first and second pressure ranges have an overlap zone.
    FIG. 2 shows a membrane manometer G2 according to another embodiment of the present invention. The diaphragm manometer G2 differs from the diaphragm manometer G shown in FIG. 1 in that it includes two mutually separated membrane pressure sensing elements. The membrane pressure sensing elements 22a and 22b are respectively formed on the silicon substrates 24a and 24b which are independent of each other. The membrane electrodes 41a and 42a have different thicknesses so that the membrane pressure sensing elements 22a and 22b have different pressure sensing ranges. It should be noted that the membrane electrodes 41a and 42a may have the same surface.
    [0017] Referring to FIG. 2, it can be assumed that the membrane electrode 42a is 7 mm square in size, and the distance between the membrane electrode 42a and the fixed electrode 5a is 9 μm. In this case, if the membrane electrode 42a has a thickness of 22 μm, it is possible to obtain the membrane pressure sensing element 22b with a full scale pressure of 100 Pa. of the principle that the membrane electrode 41a has a size of 7 mm squared, that the distance between the membrane electrode 41a and the fixed electrode 5b is 9 μm, and that the membrane electrode 41a has a thickness of 200 pm. In this case, it is possible to obtain the membrane pressure sensing element 22a with a full scale pressure of 100,000 Pa. Although the membrane pressure sensing elements 22b and 22a can be manufactured by a technique the same effect can be achieved by using membrane pressure sensing elements manufactured by a machining process. Although the membrane manometer G has been described with reference to FIGS. 4 and 5, the description of "membrane electrodes 41 and 42", which has been made with reference to FIGS. 4 and 5, can be read as that of the "membrane electrodes 41a and 42a" of the G2 diaphragm manometer.
    FIG. Fig. 3 is a block diagram showing the systematic configuration of the membrane pressure gauge G. The control circuit for the membrane pressure gauge G includes membrane pressure sensing elements 32 and 33, C / D converters 21, a central processing unit (CPU) 23, a temperature detector 28, a measurement pressure adjusting device 27, a memory 25, a D / A converter 29, and an I / O output terminal 31. The pressure sensing element membrane 32 has a capacitor structure (the low pressure side detector) constituted by the membrane electrode 42 and the fixed electrode 5a in the membrane pressure gauge G. The membrane pressure sensing element 33 has a capacitor structure (the high-pressure range detector) constituted by the membrane electrode 41 and the fixed electrode 5b in the G-membrane manometer. On the other hand, in the G2 membrane manometer the The membrane pressure sensing element 32 has a capacitor structure formed by the membrane electrode 42a and the fixed electrode 5a, and the membrane pressure sensing element 33 has a capacitor structure formed by the electrode. membrane 41a and the fixed electrode 5b. The C / D converters 21 are respectively provided for the pressure sensing elements 32 and 33, and are configured to convert the capacitance values produced by the pressure sensing elements 32 and 33 into digital values. The memory 25 is a storage device allowing the central processing unit (CPU) 23 to perform write access and read access. The D / A converter 29 converts the digital value produced by the central processing unit (CPU) 23 into an analog value.
    The C / D converters 21 convert the analog signals (the capacitance values) produced by the pressure sensing elements 32 and 33 into digital values (the numerical values of the capacitance values) and send them to the central unit. 23. The central processing unit (CPU) 23 converts the numerical value indicating the capacitance value supplied by the C / D converter 21 to the numerical value by indicating the pressure value by performing a processing based on the measured value obtained by the temperature detector 28 and the signals of the measured pressure adjusting device 27 and the memory 25, and sending the digital value to the D / A converter 29. The D / A converter 29 produces an output signal (the voltage value indicating the pressure value) corresponding to the numerical value indicating the input pressure value, as an analog value, to the electrical output terminal 12. A at this time, the D / A converter 29 also produces information indicating that the signal output from the electrical output terminal 12 is the output measured by a specific element between the pressure sensing elements 32 and 33 from the output terminal I / O 31 outwards.
    The number of membrane electrodes 41 and 42 of the membrane pressure sensing element 18 is not limited to two, and may be three or more. When the pressure sensing elements 32 and 33 produce pressure values as capacitance values (the output of the first detector or the second detector), the pressure sensing elements 32 and 33 are connected to the converters C / D 21 which convert. capacity values in numerical values. In addition, if the pressure sensing elements 32 and 33 are elements for producing the pressure values as the voltage values, the pressure sensing elements 32 and 33 are connected to the A / D converters instead of the voltage sensing elements 32 and 33. C / D converters 21 to provide digital values indicating voltage values to the central processing unit (CPU) 23.
    Outlets of the pressure sensing elements 32 and 33 may change due to changes in ambient temperature in addition to the pressure. For this reason, this pressure gauge collects the output characteristics of the digital values for each ambient temperature (detected by the temperature sensor 28 in Fig. 3) of the pressure sensing elements 32 and 33 as given in advance and stores the Temperature characteristic data in the memory 25. It should be noted that the measured pressure adjustment device 27 will be described later.
    FIG. 4 is a graph showing the relationship between the measurement pressures and the numerical values of the capacitance values produced by each C / D converter 21. Referring to FIG. 4, the characteristic A indicates the output characteristic of a pressure sensing element with a full scale pressure of 100 Pa, and the characteristic B indicates the output characteristic of a 100000 full scale pressure sensing element. Pa. In the G and G2 diaphragm manometers, the characteristic A indicates the output from the pressure sensing element (the low-pressure side detector or the first detector) with the fixed electrode 5a, and the characteristic B indicates the output from the pressure sensing element (the high pressure range detector or the second detector) with the fixed electrode 5b. In the range with the measurement pressure higher than 100 Pa, the central processing unit (CPU) 23 processes the output signal (the numerical value of the capacitance) indicating the pressure detected by the pressure sensing element with the fixed electrode 5b with the full scale pressure of 100,000 Pa, thereby generating a numerical value indicative of the pressure value. In the range with the measurement pressure lower than 100 Pa, the central processing unit (CPU) 23 processes the output signal (the numerical value of the capacitance) indicating the pressure detected by the pressure sensing element with the fixed electrode 5a with the full scale pressure of 100 Pa, thereby generating a numerical value indicative of the pressure value. The D / A converter 29 produces the digital value indicating the pressure value as the voltage value (the analog value) indicating the output value, through the output terminal. The central processing unit (CPU) 23 corrects the digital value indicating the pressure value based on a signal indicating the temperature supplied by the temperature detector 28 and the temperature characteristic data in the memory 25, and produces the corrected value . That is, the central processing unit (CPU) 23 produces the numerical value indicating the pressure value whose error due to the ambient temperature is reduced. The D / A converter 29 in this way produces, through the output terminal, the value (the pressure value) whose error due to the ambient temperature is reduced.
    As a result, the diaphragm manometer G has a pressure output characteristic similar to that shown in FIG. 4. The diaphragm manometer G produces the I / O output signal shown in fig. 5 by the I / O output terminal 31. This I / O output signal indicates that the output terminal of the D / A converter 29 has produced a result of detecting a specific element between the pressure sensing elements with respectively the fixed electrode 5a and the fixed electrode 5b. With reference to FIG. 5, the low voltage (Low) indicates the I / O output signal when the D / A converter 29 has produced the detection result (the first pressure value) of the low temperature side pressure sensing element ( the fixed electrode 5a). The high voltage (High) indicates the I / O output signal when the D / A converter 29 has produced the detection result (the second pressure value) of the high pressure range pressure sensing element (the fixed electrode 5b). It should be noted that the pressure sensing elements indicated by the I / O output signals can be opposed to those described above without any problem.
    The range E indicated in gray in FIG. 4 indicates the range in which detection pressure values (the numerical capacitance values) of the pressure sensing elements 32 and 33, which are produced by the D / A29 converter, fluctuate when the ambient temperature fluctuates by + 10 ° C . Obviously, measurement errors in the measurement pressures are large in the vicinity of 100 Pa to 1000 Pa indicated by the range Z in FIG. 4. In addition, the high pressure range pressure sensing element (the fixed electrode 5b) can perform the pressure measurement although errors are large in the range of 100 Pa or less. That is, the overlap area of the high pressure range pressure sensing element and the low pressure side pressure sensing element is a range equal to or less than 100 Pa (0). at 100 Pa). The diaphragm manometer G is therefore configured to always correct the sensing pressure value (the numerical value of the capacitance or the second pressure value) of the high pressure range pressure sensing element (the fixed electrode 5b) based on the sensing pressure value (the numerical value of the capacitance or the first pressure value) of the low pressure sensing element (the fixed electrode 5a) in the measurement pressure range equal to or less than 100 Pa.
    FIG. 6 is a graph showing the relationship between the measurement pressures and the digital capacitance values produced by the central processing unit (CPU) 23. The pressure gauge corrects the numerical value of the capacity of the pressure sensing element with the fixed electrode 5b based on the numerical value of the capacity of the pressure sensing element with the fixed electrode 5a. With this correction, as shown in FIG. 6, the diaphragm manometer G increases the accuracy of the sensing pressure value (the numerical value of the capacitance) of the pressure sensing element (the fixed electrode 5b) on the high pressure range in proximity to the values measurement of 100 Pa to 1000 Pa. A specific arrangement for correcting the detection output value (the second pressure value) of the fixed electrode 5b will be described later.
    On the other hand, as shown in FIG. 7, the membrane manometer G may be configured to cause the digital pressure values generated by the central processing unit (CPU) 23 to have a linear relationship with the log pressure values in the full pressure measurement range. . More specifically, the central processing unit (CPU) 23 produces the numerical value of the pressure after converting the pressure change to an output voltage of an order of magnitude on the ordinate in FIG. 4 (the numerical value of the capacitance) in the output voltage change of 0.5 V. Although the gray part in fig. 7 shows an example of pressure measurement errors caused by ambient temperature fluctuations, since FIG. 7 represents pressures calculated on the basis of the characteristic in FIG. 6, the increase of the pressure measurement error in the vicinity of 100 Pa to 1000 Pa shown in FIG. 6 is eliminated.
    The measured pressure adjustment device 27 (the external input means) will be described below. The measured pressure adjusting device 27 is a device which forcibly adjusts the pressure measurement error in a region with low pressure measurements equal to or less than 1/10 of the full scale pressure of the manometer, and which is connected to the central processing unit (CPU) 23 as shown in FIG. 3. For example, the pressure gauge can reduce the pressure measurement error by measuring a pressure of 1 Pa or less by adjusting the measurement pressure by 0.01 Pa or less to forcefully adjust the numerical value of the pressure. generated by the central processing unit (CPU) 23 to the D / A converter 29 from 0 to 0.001 V. More specifically, on receiving a signal from the pressure measuring adjustment device 27, the central processing unit processing (CPU) 23 adjusts the digital value of the pressure output of the D / A converter 29 from 0 to 0.001 V. The condition for the pressure measuring adjustment device 27 to produce a signal to the central processing unit (CPU) 23 is, for example, the moment when the user presses a pushbutton provided on the pressure measuring adjustment device 27.
    That is, the pressure measurement adjusting device 27 is a device that is used by the user to forcefully adjust the pressure measured from the outside. If, for example, an error has occurred concerning the initial point of the G diaphragm manometer, the user evacuates the vacuum chamber to a sufficiently low pressure and presses the pusher or adjusts a trimmer and forcibly resets the measured value pressure sensor of the low pressure side (the membrane electrode 42) at a predetermined measured pressure. Since the pressure measurement adjusting device 27 is configured to include the pusher, the user can easily adjust the initial point. This improves usability.
    When the pressure is 0.01 Pa or less, it is possible to detect it using, for example, a vacuometer for the measurement of high vacuum pressures such as a manometer B-A. In some cases, it is possible to estimate or measure the moment taken to set the pressure to 0.01 Pa or less based on the arrangement of the exhaust system and the size of the vacuum chamber, and to arrange the pusher so that he can be squeezed during this moment. Of course, the manometer may be configured to cause the pressure measuring adjustment device 27 to produce a signal to the central processing unit (CPU) 23 when the vacuum gauge detects that the pressure becomes 0.01 Pa or less.
    The output voltage of the membrane pressure gauge G may be a negative value in a low pressure range. That is, the output voltage value from the diaphragm manometer G becomes a negative output in the pressure range with the pressure of 0.1 Pa or less, and the manometer may indicate an unrealistic measurement result (a negative measured pressure). For this reason, the central processing unit (CPU) 23 can be configured to actuate the pressure measuring adjustment device 27 to correct, following calculations of the measured pressure value as a negative value, the error between its current pressure value and the pressure measurement by forcibly converting the measured pressure to a positive value (for example, 0.0001 Pa) as close as possible to zero.
    An arrangement for correcting the detection output value of the pressure sensing element with the fixed electrode 5b will be described next. Fig. 8 is a flow diagram for correcting the detection output value of the pressure sensing element with the fixed electrode 5b. It should be noted that in the description with reference to FIG. 8, the "measured pressure value" is, for example, the detection output value (the numerical value of the capacitance), and is the value (the first and second pressure values) proportional to the capacitances of the fixed electrodes 5a and 5b. When the membrane pressure gauge G starts the measurement (step S001), the central processing unit (CPU) 23 determines in step S002 whether the pressure measuring adjustment device 27 (the external input means) has issued an instruction. If YES at step S002, the process proceeds to step S003. In step S003, the central processing unit (CPU) 23 forcibly adjusts the measured pressure value of the low pressure side sensor (the pressure sensing element with the fixed electrode 5a) to the value set predetermined pressure, stores the set predetermined pressure value in the memory 25, and produces the measured pressure value to the display device, to a personal computer, or similar to the step S004.
    A case in which the pressure measurement adjusting device 27 is used as the initial point setting means will be described below. If the set predetermined pressure value is 0.01 Pa, the central processing unit (CPU) 23 produces the measured pressure value of the detector on the low pressure side (the fixed electrode 5a) as the numerical value of the pressure corresponding to 0.01 Pa in step S004. In this embodiment, when the pressure measuring adjustment device 27 is activated, the central processing unit (CPU) 23 produces the digital value of the pressure corresponding to 0.01 Pa at the D / A converter, and stores the measured pressure value by the detector of the low pressure side (the fixed electrode 5a) at the moment as the measured pressure value corresponding to 0.01 Pa in the memory 25. In the embodiment, the set pressure value However, this value can be set to 0 Pa or 0.001 Pa. By using the pressure measurement adjustment device 27 as a means other than the initial point adjustment means, the user changes this preset pressure setting value.
    If NO in step S002, the central processing unit (CPU) 23 determines in step S005 whether the measured pressure value by the detector on the low pressure side (the fixed electrode 5a) is equal. at or below full scale (100 Pa). If YES at step S005, the process proceeds to step S006. In step S006, the central processing unit (CPU) 23 stores in the memory 25 the correction value (the signal value corresponding to the pressure difference) which is calculated by (a) the pressure value calculated from the measured pressure value by the pressure sensing element (the high pressure range detector or the second detector) with the fixed electrode 5b and (b) the measured pressure value by the sensing element of the pressure sensor. pressure (the detector at the low pressure side or the first detector) with the fixed electrode 5a. In step S009 (described later), the central processing unit (CPU) 23 corrects the measured pressure value by the high pressure range detector (the pressure sensing element with the fixed electrode 5b). using the correction value and the measured pressure value by the detector at the low pressure side in step S005. More specifically, the central processing unit (CPU) 23 corrects the measured pressure value by the high pressure range detector by adding the correction value thereto. In step S007, the central processing unit (CPU) 23 produces the digital value of the pressure corresponding to the measured pressure value by the detector on the low pressure side (the pressure sensing element with the electrode fixed 5a). In step S007, since the central processing unit (CPU) 23 refers to the data of the temperature detector 25 and the data in the memory, the digital value of the pressure produced by the central processing unit (CPU) 23 has been corrected for the influence of the ambient temperature.
    If NO in step S005, the process proceeds to step S008. In step S008, the central processing unit (CPU) 23 determines whether the measured pressure value by the high pressure range detector (the pressure sensing element with the fixed electrode 5b) is equal to or less than full scale (100,000 Pa). If YES at step S008, the process proceeds to step S009. In step S009, the central processing unit (CPU) 23 corrects the measured measured pressure from the measured pressure value by the high pressure range detector (the fixed electrode 5b) using the correction value stored in the memory 25 in step S006, and produces the value obtained by the output terminal of the D / A converter 29. If NO in step S008, the process proceeds to step S010. In step S010, the central processing unit (CPU) 23 produces an out of range signal or the measurement pressure value by the high pressure range detector. It should be noted that the central processing unit (CPU) 23 repeatedly executes the processing shown in the flow diagram above (step S001 to END).
    The correction processing in step S009 will be described below with reference to FIG. 9. FIG. 9 is a flow diagram for processing in step S009. First, the central processing unit (CPU) 23 reads the value D1 produced by the C / D converter 21 connected to the high pressure range detector (the pressure sensing element with the fixed electrode 5b) 33 (step S102). The central processing unit (CPU) 23 then reads the output value D2 of the temperature detector 28 and the correction value stored in the memory 25 (steps S103 and S104). The central processing unit (CPU) 23 calculates the pressure value based on the values of D1, D2, and δ (step S105), and produces the outside pressure value by the D / A converter 29 (step S106). In this case, the central processing unit (CPU) 23 overwrites the memory 25 with the last correction value δ each time the detector of the low pressure side 32 is activated. That is, the central processing unit (CPU) 23 updates the correction value δ whenever the pressure in the measurement atmosphere decreases towards the pressure measurement range of the detector on the low pressure side. 32, and thus the measured pressure value in the pressure range in which the high pressure range detector 33 turns on, becomes stable and accurate.
    A specific arrangement for correcting the pressure measured by the high pressure range detector 33 will be described next. As described above, the correction value (the signal value) δ is the value which is the value of a signal to be produced by the high pressure range detector 33 and which corresponds to the difference between (a) ) the calculated measured pressure from the pressure value measured by the detector at the low pressure side 32 when the detector 32 is measuring for an arbitrary pressure in the pressure measurement range of the detector at the low pressure side 32, and (b ) the calculated measured pressure from the pressure value measured by the high pressure range detector 33 when the detector 33 makes a measurement for the arbitrary pressure. The procedure for acquiring the correction value δ will be described. First, the pressure value converted from the numerical value (the numerical value of the capacitance) produced by the C / D converter 21 for the low pressure side detector 32 is determined as the measured pressure value (the first value). pressure) by the low pressure side detector 32. On the other hand, the pressure value converted from the digital value (the numerical value of the capacitance) produced by the C / D converter 21 for the range detector to The high pressure 33 is determined as the measured pressure value (the second pressure value) by the high pressure range detector 33. The central processing unit (CPU) 23 acquires the difference between the pressure value measured by the low pressure side detector 32 and the pressure value measured by the high pressure range detector 33. The correction value (the signal value) 5 is the value obtained by converting the difference between the pressure value measured by the detector at the low pressure side 32 and the pressure value measured by the high pressure range detector 33 into a digital value produced by the high pressure range detector 33.
    Although the pressure (the predetermined pressure) measured at the time of acquisition of the correction value (the signal value) δ can be an arbitrary pressure in the pressure measurement range (the first pressure range) of the low pressure side detector 32, the pressure is preferably a value in the vicinity of the pressure at which the low pressure side detector 32 is exchanged against the high pressure range detector 33, i.e., a value near the upper limit of the pressure range of the low pressure side 32 detector. This is because the measurement error in the high pressure range detector 33 can be decreased. It should be noted that since the pressure measurement range of the low pressure side detector 32 in this embodiment is 100 Pa or less, the pressure (the predetermined pressure) measured at the time of acquisition of the correction value δ is preferably 100 Pa. This makes it possible to reduce the error in the high pressure range detector 33 to the pressure (100 Pa) at which the value that will be produced by the D / A converter 29 is exchanged for the value. measured based on the low pressure side detector 32 to the measured value based on the high pressure range detector 33.
    This embodiment illustrates the case in which the number of pressure sensing elements (the capacitor structures constituted by the membrane electrodes and the fixed electrodes) is two. The present invention can be applied to an arrangement with three or more membrane electrodes, which can more precisely obtain the pressure in a wider range.
    With the membrane manometer according to the present invention, since the measurement pressure for the acquisition of the correction value can be an arbitrary pressure in the measurement pressure range of the detector on the low pressure side, the manometer can configured to facilitate the correction value acquisition operation and to provide high accuracy throughout the high pressure range with a relatively simple device arrangement. In addition, it is possible to facilitate the correction operation by automatically acquiring a correction value when the pressure in a space that is measured by the membrane manometer of the present invention passes through the pressure (100 Pa in the embodiment). above) to which the measured value based on the detector at the low pressure side is exchanged at the measured value based on the high pressure range detector. This makes it possible to provide an easy-to-use membrane manometer.
    A single diaphragm manometer according to the present invention can measure the pressure in a wide range. It is possible to correct the measurement error due to fluctuations in the ambient temperature. In addition, the use of the measured pressure adjustment device 27 can prevent the measured pressure from becoming a negative value and adjust the output voltage value.
    The present invention is not limited to the above embodiments and various changes and modifications may be made within the spirit and scope of the present invention. Therefore, to inform the public of the scope of the present invention, the following claims are made.
    This application claims the priority of Japanese Patent Application No. JP 2011-220565 filed October 5, 2011, which is hereby incorporated by reference.
    权利要求:
    Claims (6)
    [1]
    List of reference signs [0043] G, G2: diaphragm pressure gauge, 1: reference pressure chamber, 2: vacuum device, 3: housing, 4, 4a, 41, 42, 41a, 42a: membrane electrode; 5: fixed electrode; 6: getter, 7: electrical circuit, 8: elastic structure, 9: conductive wiring, 10: correction electrode, 11: rigid structure, 12: electrical output terminal, 13: insulating substrate, 14, 24: silicon substrate, 15: projection structure, 16: electrode pad, 17: I / O output terminal, 18, 22: membrane pressure sensing element, 19: input terminal, 21: C / D converter, 23: central processing unit (CPU), 25: memory, 27: measured pressure adjustment device, 28: temperature detector, 29: D / A converter, 31: I / O output terminal, 32, 33: pressure detection Claims
    A membrane manometer (G), comprising: a first detector (42) configured to sense pressure in a first pressure range; a second detector (41) configured to sense the pressure in a second pressure range, each of said first and second sensors being configured to measure a pressure relative to a reference pressure in a reference pressure chamber; and a processing unit (23) which is configured to determine the measured pressure based on the outputs of said first detector and said second detector, wherein the first pressure range and the second pressure range have an overlap range, wherein the upper limit of the second pressure range is higher than the upper limit of the first pressure range, wherein said processing unit is configured to determine a correction value based on the outputs of said first detector and said second detector when the pressure falls within the overlap range, and wherein said processing unit is configured to determine the pressure value based on the output of said second detector and on the correction value, when measuring, using said second detector, pressure in the second pressure range, which is higher than the upper limit of the first first pressure range.
    [2]
    The membrane pressure gauge (G) according to claim 1, wherein said processing unit is configured to determine a first measured pressure value corresponding to a signal produced by said first detector and a second measured pressure value corresponding to a signal produced. by said second detector, and for calculating a signal value which is the value of the signal to be generated by said second detector and which corresponds to the difference between the first measured pressure value and the second measured pressure value, when said first detector detector and said second detector perform detection in the overlap range, and wherein said processing unit is configured to produce a measured pressure value corresponding to a signal obtained by adding said signal value to a signal produced by said second detector, when measuring the pressure in the second range of pr ession that is higher than the upper limit of the first pressure range.
    [3]
    The membrane pressure gauge (G) according to claim 2, wherein said first detector and said second detector are configured to detect pressures at the upper limit of the first pressure range so that said processing unit determines the first pressure value and the second pressure value based on the outputs of said first detector and said second detector.
    [4]
    The membrane pressure gauge (G) according to claim 2, further comprising an external input unit connected to said processing unit, wherein said processing unit is configured to perform a setting operation so that a value of predetermined measured pressure is determined to be output when a signal is output from said first detector, which is similar to a signal output of said first detector upon receipt of a signal produced by said external input unit.
    [5]
    The membrane pressure gauge (G) according to any one of claims 2 to 4, further comprising a storage unit connected to said processing unit, wherein said processing unit is configured to store, in said storage unit, the signal value of said second detector, which corresponds to the difference, and wherein said processing unit is configured to read the signal value of said storage unit and to add the signal value to an output by said second detector, when measuring the pressure in the second pressure range which is higher than the upper limit of the first pressure range.
    [6]
    The membrane pressure gauge (G) according to claim 5, wherein the processing unit is configured to overwrite the signal value that was stored in said storage unit by a new signal value when a new signal value is to be stored in said storage unit.
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    WO2013051198A1|2013-04-11|
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    法律状态:
    2017-07-31| PK| Correction|Free format text: RECTIFICATION INVENTEUR |
    优先权:
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