JP2010151599A - Method for manufacturing pressure sensor and pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a pressure sensor which uses a cylindrical vibrator which has been so far unable to be used for a pressure sensor and provide the pressure sensor. <P>SOLUTION: The method for manufacturing the pressure sensor includes a pressure sensor including a cylindrical vibrator having a characteristic frequency in accordance with the pressure of an object under measurement therewithin, an excitation piezoelectric element provided on the periphery of the cylindrical vibrator, and two facing vibration detection piezoelectric elements provided on the periphery of the cylindrical vibrator. The method includes an insertion loss measuring process for measuring the insertion losses of the excitation piezoelectric element and the vibration detection piezoelectric elements for each frequency and a vibration detection position moving process for moving at least one vibration detection position of the vibration detection piezoelectric elements in the circumferential direction of the cylindrical vibrator when the difference between the insertion losses of two adjacent characteristic vibration modes does not exceed a predetermined threshold as a result of the measurement in the insertion loss measuring process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure sensor manufacturing method and pressure sensor used for precise measurement of gas or liquid pressure.

Conventionally, a pressure sensor using a cylindrical vibrator has been used for precise measurement of gas or liquid pressure when determining the air-fuel ratio of a jet engine.
For example, as the pressure sensor, the following Patent Document 1 discloses a pressure sensor that can accurately measure even at the time of activation. This pressure sensor has a cylindrical vibrator having a thin cylindrical portion whose upper surface is closed and whose lower surface is opened, and a cylindrical shape coaxial with the cylindrical vibrator, and the cylindrical portion of the cylindrical vibrator is fitted inside the cylindrical vibrator. Thus, the gap between the cylindrical vibrator and the cylindrical vibrator is composed of a housing, and four piezoelectric elements mounted at equal intervals in the circumferential direction in a groove provided outside the base of the cylindrical vibrator. Two of the four piezoelectric elements are connected to the input side of the amplifier, and the remaining two piezoelectric elements are connected to the output side of the amplifier. The four piezoelectric elements and the amplifier circuit constitute an oscillation circuit, and the cylindrical vibrator is self-excited.

And each piezoelectric element in such a pressure sensor is comprised so that a piezoelectric element may be pinched | interposed with a pair of thin film-like electrodes, and each is formed in the substantially disc shape. A pressure port to which a gas or a liquid (measuring object) to be measured for pressure is supplied is connected to the proximal end side in the axial direction of the cylindrical vibrator of the pressure sensor. The cylindrical portion is distorted by the pressure of the object to be measured supplied from the pressure port to the cylindrical vibrator, and the natural frequency of the cylindrical vibrator is changed by the receiver of the cylindrical portion. The natural frequency signal input from the piezoelectric element to the receiver changes with the natural frequency of the cylindrical vibrator, and the receiver calculates the pressure of the object to be measured based on this natural frequency signal.
JP 2000-352537 A

  By the way, in the above prior art, the oscillation circuit oscillates using a specific vibration frequency, and the cylindrical vibrator is vibrated by the oscillation. However, since the cylindrical vibrators in the pressure sensor described above are manufactured by mechanical work, it is very difficult to make all the cylindrical vibrators have a thickness that is nearly uniform in the circumferential direction. When a cylindrical vibrator having a non-uniform thickness is used as a pressure sensor, two adjacent natural vibration modes with a small difference in insertion loss may occur. The pressure sensor oscillates using the frequency of either of these two natural vibration modes, but in order to oscillate by always selecting the same frequency of the two frequencies by the circuit, the insertion loss is It must be separated by 3 dB (decibel) or more.

  However, in the pressure sensor, if the difference in insertion loss between the two natural vibration modes becomes 3 dB or less, the frequencies of the two natural vibration modes may be close, and the same frequency cannot always be selected by the circuit. End up. In the pressure sensor, if the same frequency cannot always be selected by the circuit, the oscillation becomes unstable, so that it cannot function sufficiently as a sensor. Currently, the cylindrical vibrator that causes such a problem cannot be used for the pressure sensor, and is discarded.

  The present invention has been made in view of the above-described circumstances, and provides a pressure sensor manufacturing method and a pressure sensor that can use a cylindrical vibrator that could not be used conventionally as a pressure sensor.

  In order to achieve the above object, according to the present invention, as a first solving means related to a pressure sensor manufacturing method, a cylindrical vibrator having a natural frequency corresponding to the pressure of an object to be measured, and the cylindrical vibrator A method of manufacturing a pressure sensor comprising: a vibrating piezoelectric element provided on an outer peripheral surface of the cylindrical vibrator; and two vibration detecting piezoelectric elements provided on an outer peripheral surface of the cylindrical vibrator so as to face each other. As a result of the insertion loss measurement step for measuring the insertion loss for each frequency of the excitation piezoelectric element and the vibration detection piezoelectric element, and the measurement of the insertion loss measurement step, the insertion loss of two adjacent natural vibration modes A vibration detection position moving step of shifting at least one vibration detection position of the vibration detection piezoelectric element in a circumferential direction of the cylindrical vibrator when the difference is equal to or less than a predetermined threshold value. adopt.

  In the present invention, as a second solving means relating to the pressure sensor manufacturing method, in the first solving means, in the vibration detection position moving step, the difference in insertion loss between two adjacent natural vibration modes is a predetermined threshold. The electrode on the contact side of at least one of the cylindrical vibrators of the vibration detecting piezoelectric element is divided into a plurality of divided electrodes in the circumferential direction of the cylindrical vibrator, and the circumference of the divided electrodes Adopting means for shifting at least one vibration detection position of the vibration detecting piezoelectric element in the circumferential direction of the cylindrical vibrator by attaching the vibration detecting piezoelectric element so as to contact any one shifted in the direction To do.

  In the present invention, as a first solving means related to the pressure sensor, a cylindrical vibrator having a natural frequency corresponding to the pressure of an internal object to be measured, and an excitation provided on the outer peripheral surface of the cylindrical vibrator. A pressure sensor, and two vibration detecting piezoelectric elements provided on an outer peripheral surface of the cylindrical vibrator so as to face each other, wherein at least one cylinder of the vibration detecting piezoelectric element is provided. The electrode on the contact side of the vibrator is a divided electrode divided into a plurality of parts in the circumferential direction, and the insertion loss for measuring the insertion loss for each frequency between the excitation piezoelectric element and the vibration detection piezoelectric element. As a result of measurement by the measuring means and the insertion loss measuring means, when the difference in insertion loss between two adjacent natural vibration modes is equal to or less than a predetermined threshold, the divided electrode to be used is shifted in the circumferential direction. Switch to one of the split electrodes By Rukoto, employing switching means for shifting the vibration detecting position in the circumferential direction, a means that includes.

  According to the present invention, a pressure sensor manufacturing method includes: a cylindrical vibrator having a natural frequency corresponding to the pressure of an internal object to be measured; a vibrating piezoelectric element provided on an outer peripheral surface of the cylindrical vibrator; A pressure sensor manufacturing method comprising: two vibration detection piezoelectric elements provided on an outer peripheral surface of a cylindrical vibrator so as to face each other, wherein each frequency of the vibration piezoelectric element and the vibration detection piezoelectric element is When the difference between the insertion loss of two adjacent natural vibration modes is equal to or less than a predetermined threshold as a result of the measurement in the insertion loss measurement step for measuring the insertion loss and the insertion loss measurement step, the piezoelectric element for vibration detection A vibration detection position moving step of shifting at least one of the vibration detection positions in the circumferential direction of the cylindrical vibrator.

  Thereby, in the pressure sensor, since the difference in insertion loss between the two natural vibration modes becomes equal to or greater than a predetermined threshold value, the frequency of the same natural vibration mode can always be taken out by the circuit. Therefore, the pressure sensor can stably operate the oscillation. Conventionally, cylindrical vibrators that are not uniform in thickness that cause oscillation instability have been discarded. However, the cylindrical vibrators that have been conventionally discarded by the manufacturing method of the pressure sensor according to the present embodiment are discarded. Can be used for the pressure sensor A.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a method for manufacturing a pressure sensor.
FIG. 1 is a diagram illustrating a schematic configuration of a pressure sensor A which is a manufacturing target of the manufacturing method of the pressure sensor according to the present embodiment. FIG. 1A is a partial cross-sectional view showing a schematic configuration of the pressure sensor A, and FIG. 1B is a functional block diagram showing a schematic configuration of the pressure sensor A.
As shown in FIG. 1, the pressure sensor A includes a cylindrical vibrator 1, a housing 2, a pressure port 3, vibration detection piezoelectric elements 4a and 4b, excitation piezoelectric elements 4c and 4d, and an amplifier 5.

  The cylindrical vibrator 1 is made of a constant elastic alloy, and as shown in FIG. 1A, a thin cylindrical portion 1a whose upper surface is closed, and a lower portion of the cylindrical portion 1a are coaxial with the cylindrical portion 1a. And a cylindrical base 1b formed integrally. The cylindrical portion 1a is fitted inside the cylindrical housing 2 which is coaxial with itself and whose diameter is the same as the diameter of the base portion 1b. The upper surface of the cylindrical portion 1 a closes the upper opening 2 a of the housing 2, and the upper surface of the base portion 1 b closes the lower opening 2 b of the housing 2, thereby forming a vacuum chamber 6 that is a gap between the cylindrical vibrator 1 and the housing 2. .

  The base portion 1b is formed with a substantially ring groove-shaped groove portion 1c extending in the circumferential direction. A circumferential surface along the circumferential direction inside the groove 1 c forms an outer circumferential surface of the cylindrical vibrator 1 that vibrates. Four piezoelectric elements, that is, vibration detecting piezoelectric elements 4a and 4b and exciting piezoelectric elements 4c and 4d are attached at equal intervals in the circumferential direction on the inner circumferential surface of the groove 1c. Further, a base 1d having an enlarged diameter of the base 1b is formed below the base 1b of the cylindrical vibrator 1. A connecting hole 1e for connecting to the pressure port 3 is formed in the central portion in the radial direction of the base portion 1d along the axis X direction.

  The housing 2 is formed in a substantially cylindrical shape, and an upper opening 2a is formed on the upper surface side and a lower opening 2b is formed on the lower surface side. The housing 2 is fitted with the cylindrical portion 1a of the cylindrical vibrator 1 on the inner side thereof, and covers the outer peripheral surface of the cylindrical portion 1a from the upper surface of the cylindrical portion 1a to the vicinity of the upper surface of the base portion 1b. In the pressure sensor A, a substantially cylindrical shape is thus formed by the cylindrical vibrator 1 and the housing 2. The outer dimensions of the substantially cylindrical shape of the pressure sensor A are about φ16 mm in diameter and about 20 to 30 mm in height in the axis X direction.

  The pressure port 3 is provided with a cylindrical supply port for supplying a gas or liquid (measurement object) having a pressure P to the inside of the cylindrical vibrator 1. The supply port of the pressure port 3 is connected to the cylindrical vibrator 1 by being fitted into a connection hole 1 e provided in the base 1 d of the cylindrical vibrator 1. The pressure port 3 supplies a gas or a liquid having a pressure P to the cylindrical vibrator 1.

  The vibration detecting piezoelectric elements 4a and 4b and the vibrating piezoelectric elements 4c and 4d are attached to the circumferential surface inside the groove 1c provided in the base 1b of the cylindrical vibrator 1 at equal intervals along the circumferential direction. It has been. That is, the vibration detecting piezoelectric elements 4a and 4b are attached to the inner circumferential surface of the groove 1c so as to face each other, and the excitation piezoelectric elements 4c and 4d are arranged on the inner circle of the groove 1c so as to face each other. It is attached to the peripheral surface. The vibration detecting piezoelectric elements 4a and 4b and the exciting piezoelectric elements 4c and 4d are each formed in a substantially disc shape or a substantially circular thin film shape, and are configured by stacking a positive electrode, a piezoelectric body, and a negative electrode. Yes. The vibration detecting piezoelectric elements 4a and 4b and the vibrating piezoelectric elements 4c and 4d are attached to the cylindrical vibrator so that the positive electrode contacts the cylindrical vibrator. For example, the vibration detecting piezoelectric elements 4a and 4b and the vibrating piezoelectric elements 4c and 4d have a diameter of about φ3.6 mm and a thickness of about 0.15 mm.

  As shown in FIG. 1B, the amplifier 5 has its inputs connected to the outputs of the vibration detecting piezoelectric elements 4a and 4b. The output of the amplifier 5 is connected to the excitation piezoelectric elements 4c and 4d. The amplifier 5, the vibration detecting piezoelectric elements 4a and 4b, and the exciting piezoelectric elements 4c and 4d constitute an oscillation circuit, and the cylindrical vibrator 1 of the pressure sensor A is self-excited.

  Then, the pressure sensor A outputs the natural frequency signal sf amplified by the amplifier 5 to the receiver B, as shown in FIG. In the receiver B, a CPU (Central Processing Unit) executes a control program stored in a ROM (Read Only Memory), whereby the pressure P of the gas or liquid that is the object to be measured based on the natural vibration signal vs. And the calculated result is displayed on the display unit.

Next, the steps of the pressure sensor manufacturing method will be described using the pressure sensor A. FIG. 2 is a system configuration diagram of the insertion loss measurement process of the pressure sensor manufacturing method according to the present embodiment.
First, in the insertion loss measurement step, as shown in FIG. 2, the amplifier 5 is removed from the pressure sensor A, and a spectrum analyzer C is connected instead. At this time, the vibration detecting piezoelectric elements 4a and 4b are connected to the input of the spectrum analyzer C. In addition, the piezoelectric elements 4 c and 4 d for vibration are connected to the output of the spectrum analyzer C. The spectrum analyzer C measures the insertion loss for each frequency and outputs the assumed result as a frequency spectrum.

  When the thickness of the cylindrical vibrator 1 of the pressure sensor A is not uniform in the circumferential direction, the spectrum analyzer C outputs the frequency spectrum shown in FIG. 3 in the insertion loss measurement step. FIG. 3 shows the frequency output by the spectrum analyzer C when the thickness of the cylindrical vibrator 1 of the pressure sensor A is not uniform in the circumferential direction in the insertion loss measurement step of the pressure sensor manufacturing method according to the present embodiment. It is a figure which shows a spectrum. In FIG. 3, the vertical axis represents insertion loss and the horizontal axis represents frequency.

  When the thickness of the cylindrical vibrator 1 of the pressure sensor A is not uniform in the circumferential direction, as shown in FIG. 3, two adjacent peaks whose insertion loss difference is 2.7 dB (decibel) in the frequency spectrum. Appears. These two peaks indicate that two natural vibration modes having different vibration frequencies are generated in the self-excited vibration of the cylindrical vibrator 1 of the pressure sensor A.

In the pressure sensor A, since it is necessary to operate the oscillation circuit based on one of the two natural vibration modes, only the frequency of the same natural vibration mode in the two natural vibration modes is obtained. It must always be taken out by the circuit.
However, in the pressure sensor A, when the frequencies are close as in the two natural vibration modes shown in FIG. 3, the same natural vibration mode is always extracted by the circuit unless there is a difference of 3 dB (decibel) or more in the insertion loss. The oscillation becomes unstable. In the pressure sensor A, when two natural vibration modes having different vibration frequencies are generated, pressure is applied to the vibration detecting piezoelectric element 4a by two antinodes in the vibration of the cylindrical vibrator 1, as shown in FIG. .

  Next, in the vibration detection position moving step, as a result of the insertion loss measurement in the insertion loss measurement step, when the difference in insertion loss between the two natural vibration modes is 3 dB or less as shown in the frequency spectrum shown in FIG. The positive electrode of the vibration detecting piezoelectric element 4 a is divided, and the vibration detecting piezoelectric element 4 a is attached to the cylindrical vibrator 1 so that a part of the divided positive electrode is in contact with the cylindrical vibrator 1.

FIG. 4 is a diagram showing an example of division of the positive electrode of the vibration detecting piezoelectric element 4a in the vibration detecting position moving step of the pressure sensor manufacturing method according to the present embodiment.
Specifically, in the vibration detection position moving step, as shown in FIG. 4, the positive electrode of the vibration detection piezoelectric element 4 a on the side in contact with the cylindrical vibrator is substantially uniform along the circumferential direction of the cylindrical vibrator 1. And divided into two substantially evenly along the direction orthogonal to the circumferential direction to divide into four divided electrodes 14a-1 to 14a-4 having substantially the same fan shape.

Then, among the divided electrodes 14a-1 to 14a-4 of the vibration detecting piezoelectric element 4a, only the divided electrode 14a-1 (shaded portion) arranged on the upper right side shown in FIG. The vibration detecting piezoelectric element 4a is attached to the cylindrical vibrator 1 by soldering.
In the pressure sensor A, when two natural vibration modes having different vibration frequencies are generated, vibration is detected by two antinodes in the vibration of the cylindrical vibrator 1 by bringing only the divided electrode 14a-1 into contact with the cylindrical vibrator 1. The vibration detection position can be shifted in the circumferential direction of the cylindrical vibrator 1 so that pressure is applied to the vibration detection piezoelectric element 4a by only one antinode of the pressure applied to the piezoelectric element 4a for vibration. I can do it.

  FIG. 5 shows a vibration detection position in which only the divided electrode 4a-1 of the positive electrode of the vibration detection piezoelectric element 4a is in contact with the cylindrical vibrator 1 by the vibration detection position moving step of the pressure sensor manufacturing method according to this embodiment. FIG. 4 is a diagram showing a frequency spectrum output from a spectrum analyzer C when a piezoelectric element 4a is attached to a cylindrical vibrator 1; In the pressure sensor A, by bringing only the divided electrode 14a-1 into contact with the cylindrical vibrator 1, the difference in insertion loss between the two natural vibration modes is increased to 7.5 dB as shown in FIG. Thereby, in the pressure sensor A, since the difference in insertion loss between the two natural vibration modes is 3 dB or more, the frequency of the same natural vibration mode can always be extracted by the circuit.

  As described above, in the insertion loss measuring step of the pressure sensor manufacturing method according to the present embodiment, the measured insertion loss for each frequency of the oscillation circuit of the pressure sensor A is output to the spectrum analyzer C, and the vibration detection position moving step is performed. As a result of the insertion loss measurement in the insertion loss measurement step, when the difference in insertion loss between the two natural vibration modes is 3 dB or less as shown in the frequency spectrum shown in FIG. 3, as shown in FIG. The positive electrode of the piezoelectric element 4a is divided approximately equally into four divided electrodes 14a-1 to 14a-4, and the vibration detecting piezoelectric element 4a is connected to the cylindrical vibrator 1 so that the divided electrode 14a-1 contacts the cylindrical vibrator 1. By attaching to 1, the vibration detection is shifted in the circumferential direction of the cylindrical vibrator 1.

  Thereby, in the pressure sensor A, as shown in FIG. 5, since the difference in insertion loss between the two natural vibration modes is 3 dB or more, the frequency of the same natural vibration mode can always be taken out by the circuit. Therefore, the pressure sensor A can stably operate the oscillation. Conventionally, when the frequency spectrum shown in FIG. 3 is output, the cylindrical vibrator 1 whose thickness is not somewhat uniform has been discarded, but by the method of manufacturing a pressure sensor according to the present embodiment, Thus, the cylindrical vibrator 1 that has been conventionally discarded can be used for the pressure sensor A.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the pressure sensor manufacturing method of the above embodiment, in the vibration detection position moving step, as shown in FIG. 4, the positive electrode of the vibration detecting piezoelectric element 4a is divided into four, and the divided electrode 4a-1 is formed. Although the vibration detecting piezoelectric element 4a is attached so as to be in contact with the cylindrical vibrator 1, the present invention is not limited to this.
For example, the vibration detecting piezoelectric element 4a is attached to the cylindrical vibrator 1 so that any one of the divided electrodes 14a-2, 14a-3, and 14a-4 other than the divided electrode 4a-1 is in contact with the cylindrical vibrator 1. May be.

FIG. 6 is a diagram showing a modification of the vibration detection position moving step in the method for manufacturing the pressure sensor according to the present embodiment. 6A shows a modification of the division of the positive electrode of the vibration detecting piezoelectric element 4a, and FIG. 6B shows an example of the division of the positive electrode of the vibration detecting piezoelectric element 4b.
Also, as shown in FIG. 4, the positive electrode of the vibration detecting piezoelectric element 4a is not divided into four substantially fan-shaped identical shapes, but as shown in FIG. 6A, along the circumferential direction. The positive electrode of the vibration detecting piezoelectric element 4a is substantially equally divided into three divided electrodes 24a-1 to 24a-3, and one of the divided electrodes 24a-1 and 24a-3 of the vibration detecting piezoelectric element 4a is subjected to cylindrical vibration. The vibration detecting position may be shifted in the circumferential direction of the cylindrical vibrator 1 by attaching the vibration detecting piezoelectric element 4 a to the cylindrical vibrator 1 so as to be in contact with the child 1.

  In addition to the vibration detecting piezoelectric element 4a, the positive electrode of the vibration detecting piezoelectric element 4b has the same substantially fan-like shape as the vibration detecting piezoelectric element 4a, as shown in FIG. 6B. Dividing into four divided electrodes 14b-1 to 14b-4. Then, the vibration detecting piezoelectric element 4a is attached to the cylindrical vibrator 1 so that 14a-1 of the vibration detecting piezoelectric element 4a is in contact with the cylindrical vibrator, and 14b-1 and 14b-2 of the vibration detecting piezoelectric element 4b are attached. The vibration detecting piezoelectric element 4b may be attached to the cylindrical vibrator 1 so as to be in contact with the cylindrical vibrator 1. The vibration detecting piezoelectric element 4a is attached to the cylindrical vibrator 1 so that the vibration detecting piezoelectric element 4a 14a-1 contacts the cylindrical vibrator, and the vibration detecting piezoelectric element 4b 14b-1 is attached to the cylindrical vibrator 1. The vibration detecting position may be shifted in the circumferential direction of the cylindrical vibrator 1 by attaching the vibration detecting piezoelectric element 4 a to the cylindrical vibrator 1 so as to be in contact with the cylindrical vibrator 1.

(2) In the pressure sensor manufacturing method of the above embodiment, when the difference in insertion loss between two adjacent natural vibration modes is equal to or less than a predetermined threshold value by the insertion loss measurement step and the vibration detection position movement step, Although at least one vibration detection position of the piezoelectric element for vibration detection is shifted in the circumferential direction of the cylindrical vibrator, the present invention is not limited to this.

  For example, the pressure sensor A includes a vibration detecting piezoelectric element 4a in which an electrode is divided into four divided electrodes 4a-1 to 4a-4, an insertion loss measuring means, and a switching means, and the insertion loss measuring means. Measures the insertion loss for each frequency of the excitation piezoelectric elements 4c and 4d and the vibration detection piezoelectric elements 4a and 4b, and the switching means measures the two adjacent vibration modes as a result of the measurement by the insertion loss measurement means. When the difference in the insertion loss is equal to or less than a predetermined threshold value, the vibration detection position is shifted in the circumferential direction by switching the divided electrode to be used to one of the divided electrodes shifted in the circumferential direction. In this way, the pressure sensor A may automatically shift the vibration detection position in the circumferential direction when the difference in insertion loss between two adjacent natural vibration modes is equal to or smaller than a predetermined threshold value. Good.

It is a figure which shows schematic structure of the pressure sensor A which is a manufacture object of the manufacturing method of the pressure sensor which concerns on one Embodiment of this invention. It is a system block diagram of the insertion loss measurement process of the manufacturing method of the pressure sensor which concerns on one Embodiment of this invention. The frequency spectrum output by the spectrum analyzer C when the thickness of the cylindrical vibrator 1 of the pressure sensor A is not uniform in the circumferential direction in the insertion loss measurement step of the pressure sensor manufacturing method according to an embodiment of the present invention. FIG. It is a figure which shows the example of a division | segmentation of the positive electrode of the vibration detection piezoelectric element 4a of the vibration detection position moving process of the manufacturing method of the pressure sensor which concerns on one Embodiment of this invention. is there. The vibration detecting piezoelectric element is such that only the divided electrode 4a-1 of the positive electrode of the vibration detecting piezoelectric element 4a is in contact with the cylindrical vibrator 1 by the vibration detecting position moving step of the pressure sensor manufacturing method according to the embodiment of the present invention. FIG. 6 is a diagram showing a frequency spectrum output from the spectrum analyzer C when the element 4a is attached to the cylindrical vibrator 1. is there. It is a figure which shows the modification of the vibration detection position moving process of the manufacturing method of the pressure sensor which concerns on one Embodiment of this invention.

Explanation of symbols

A ... Pressure sensor, B ... Receiver, C ... Spectrum analyzer, 1 ... Cylindrical vibrator, 1a ... Cylindrical part, 1b ... Base part, 1c ... Groove part, 1d ... Base part, 1e ... Connecting hole, 2 ... Housing, 2a ... Upper opening, 2b ... lower opening, 3 ... pressure port, 4a, 4b ... piezoelectric element for vibration detection, 4c, 4d ... piezoelectric element for vibration, 5 ... amplifier, 6 ... vacuum chamber, 14a-1 to 14a-4 ... Split electrodes, 14b-1 to 14b-4 ... split electrodes, 24a-1 to 24a-3 ... split electrodes,

Claims (3)

A cylindrical vibrator having a natural frequency corresponding to the pressure of the internal object to be measured, and a vibration excitation piezoelectric element provided on the outer circumferential surface of the cylindrical vibrator are arranged on the outer circumferential surface of the cylindrical vibrator so as to face each other. A method of manufacturing a pressure sensor comprising two vibration detection piezoelectric elements provided,
An insertion loss measurement step for measuring an insertion loss for each frequency of the excitation piezoelectric element and the vibration detection piezoelectric element;
If the difference in insertion loss between two adjacent natural vibration modes is equal to or less than a predetermined threshold as a result of the measurement in the insertion loss measurement step, at least one vibration detection position of the vibration detection piezoelectric element is defined as the cylinder. The vibration detection position moving step for shifting in the circumferential direction of the vibrator,
A method for manufacturing a pressure sensor, comprising:   The vibration detection position moving step includes a contact-side electrode of at least one of the cylindrical vibrators of the vibration detection piezoelectric element when a difference in insertion loss between two adjacent natural vibration modes is a predetermined threshold value or less. Is divided into a plurality of divided electrodes in the circumferential direction of the cylindrical vibrator, and the vibration detecting piezoelectric element is attached so as to contact any one of the divided electrodes displaced in the circumferential direction. The method for manufacturing a pressure sensor according to claim 1, wherein at least one vibration detection position of the piezoelectric element is shifted in a circumferential direction of the cylindrical vibrator. A cylindrical vibrator having a natural frequency corresponding to the pressure of the internal object to be measured, and a vibration excitation piezoelectric element provided on the outer circumferential surface of the cylindrical vibrator are arranged on the outer circumferential surface of the cylindrical vibrator so as to face each other. A pressure sensor comprising two vibration detection piezoelectric elements provided,
The electrode on the contact side of at least one cylindrical vibrator of the vibration detecting piezoelectric element is a divided electrode divided into a plurality in the circumferential direction,
An insertion loss measuring means for measuring an insertion loss for each frequency of the excitation piezoelectric element and the vibration detection piezoelectric element;
As a result of the measurement of the insertion loss measuring means, when the difference in insertion loss between two adjacent natural vibration modes is equal to or less than a predetermined threshold value, the divided electrode to be used is shifted in the circumferential direction. Switching means for shifting the vibration detection position in the circumferential direction by switching to any one of the following:
A pressure sensor comprising:

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