JPH0345782B2 - - Google Patents
Info
- Publication number
- JPH0345782B2 JPH0345782B2 JP59053596A JP5359684A JPH0345782B2 JP H0345782 B2 JPH0345782 B2 JP H0345782B2 JP 59053596 A JP59053596 A JP 59053596A JP 5359684 A JP5359684 A JP 5359684A JP H0345782 B2 JPH0345782 B2 JP H0345782B2
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- moisture absorbing
- frequency
- grounded
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229920001477 hydrophilic polymer Polymers 0.000 claims description 3
- 230000010287 polarization Effects 0.000 description 8
- 238000005452 bending Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 239000004020 conductor Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/121—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid for determining moisture content, e.g. humidity, of the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】
本発明は圧電素子の共振周波数或いは共振周波
数におけるインピーダンス又はアドミツタンスの
変化を利用して雰囲気中の湿度の検出を行なう湿
度センサーに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a humidity sensor that detects humidity in an atmosphere using the resonance frequency of a piezoelectric element or a change in impedance or admittance at the resonance frequency.
従来の湿度センサーは第１図に示すように、圧
電素子（例えばＹカツトされた水晶）１の両面に
（＋）電極２と（−）電極２′を固定し、その上に
親水性高分子で形成した吸湿部材３，３′を設け、
両電極２，２′に夫々リード線４，４′を接続す
る。 As shown in Figure 1, a conventional humidity sensor has a (+) electrode 2 and a (-) electrode 2' fixed on both sides of a piezoelectric element (for example, a Y-cut crystal) 1, and a hydrophilic polymer is placed on top of the (+) electrode 2 and (-) electrode 2'. Provide moisture absorbing members 3, 3' formed of
Lead wires 4 and 4' are connected to both electrodes 2 and 2', respectively.
この湿度センサーは、吸湿による吸湿部材３，
３′の重量増加で圧電素子１の共振周波数が変化
するのを利用して湿度変化を周波数変化出力とす
るようになつている。 This humidity sensor includes a moisture absorbing member 3,
Utilizing the fact that the resonant frequency of the piezoelectric element 1 changes due to an increase in the weight of the piezoelectric element 3', humidity changes are converted into a frequency change output.
前記の湿度センサーは、いずれか一方の吸湿部
材を接地できない電極側に取付けなけねばなら
ず、接地できない電極側に取付けられた吸湿部材
に、何らかの理由により接地されている導体或い
は、それに近い電気的状態のものに接触した場合
には、吸湿部材に電流が流れて焼損する等、装置
として致命的事故となる欠点がある。 In the above-mentioned humidity sensor, one of the moisture absorbing members must be attached to the electrode side that cannot be grounded, and the moisture absorbing member attached to the electrode side that cannot be grounded must be connected to a conductor that is grounded for some reason or an electrical connection close to it. If the device comes into contact with a wet object, a current will flow through the moisture absorbing member and cause it to burn out, resulting in a fatal accident for the device.
尚、接地電極側のみに吸湿部材を設けた場合に
は感度が低下することになる。 Note that if the moisture absorbing member is provided only on the ground electrode side, the sensitivity will decrease.
そこで、本発明においては、吸湿部材を常に接
地電極上に設けることにより、電流が流れて焼損
等の事故発生を防止することができる湿度センサ
ーを提供するのが目的である。 Therefore, an object of the present invention is to provide a humidity sensor that can prevent accidents such as burnout due to current flow by always providing a moisture absorbing member on the ground electrode.
本発明の構成を第２図に示す実施例に基き詳細
に説明すると、高圧側の（＋）電極２を両圧電素
子１，１で挾持し、圧電素子１，１の反（＋）電
極２側に夫々接地されている（−）電極２′，
２′を取付け、この（−）電極２′，２′の夫々表
面に親水性高分子で形成した吸湿部材３，３′を
取付けている。そして、（＋）電極２にリード線
４を、両（−）電極２′，２′に夫々リード線４′，
４′を接続して接地している。 The structure of the present invention will be explained in detail based on the embodiment shown in FIG. (-) electrodes 2', which are respectively grounded on the sides;
2', and moisture absorbing members 3, 3' made of hydrophilic polymer are attached to the surfaces of the (-) electrodes 2', 2', respectively. Then, a lead wire 4 is connected to the (+) electrode 2, and a lead wire 4' is connected to both (-) electrodes 2', 2', respectively.
4' is connected and grounded.
本実施例は前記のように構成したもので、図示
されていない交流信号発生器よりの電気信号をリ
ード線４，４′を通して電極２，２′，２′に印加
することにより、圧電素子１，１は或る瞬間に
は、矢印で示す方向へ、次の瞬間には逆の方向へ
の力が交互に働くことにより屈曲振動が発生す
る。そして、この屈曲振動の共振周波数に駆動周
波数を合せることにより、効率良く動作させるこ
とができる。 This embodiment is constructed as described above, and the piezoelectric element 1 is , 1, bending vibration occurs due to forces acting alternately in the direction indicated by the arrow at one moment and in the opposite direction at the next moment. By matching the drive frequency to the resonance frequency of this bending vibration, efficient operation can be achieved.
そして、雰囲気中の湿度の変化に応じて、両吸
湿部材３，３′へ付着する水分の量が変化するこ
とにより吸湿部材３，３′の質量は変化し、共振
周波数の変化となる。又、共振周波数におけるイ
ンピーダンス或いはアドミツタンスの変化とな
る。 The mass of the moisture absorbing members 3, 3' changes as the amount of moisture adhering to both the moisture absorbing members 3, 3' changes in accordance with changes in the humidity in the atmosphere, resulting in a change in the resonance frequency. It also results in a change in impedance or admittance at the resonant frequency.
即ち、気体中の湿度変化を、共振周波数の変化
或いは共振周波数におけるインピーダンス又はア
ドミツタンスの変化としてとらえた湿度センサー
とすることができる。 That is, the humidity sensor can detect a change in humidity in the gas as a change in resonance frequency or a change in impedance or admittance at the resonance frequency.
尚、共振周波数におけるインピーダンスを求め
るには、圧電素子１，１へ流れる電流ｉと電圧ｖ
を求めｖ／ｉとすればよく、又アドミツタンスを
求めるにはｉ／ｖとすればよい。 In addition, to find the impedance at the resonant frequency, the current i flowing to the piezoelectric elements 1 and the voltage v
It is sufficient to calculate v/i, and to obtain admittance, it is sufficient to use i/v.
本発明は前記のような構成、作用を有するもの
で、吸湿部材３，３′を接地された（−）電極
２′，２′に取付けているので、焼損事故等が発生
するようなことがなく、安全に対する高信頼度を
有するものである。 The present invention has the above-described structure and operation, and since the moisture absorbing members 3 and 3' are attached to the grounded (-) electrodes 2' and 2', there is no possibility of a burnout accident. It has a high degree of reliability in terms of safety.
圧電素子の形状が方形でＸ−方向20mm、Ｙ−方
向３mm、Ｚ−方向１mmで形成されたもので、厚さ
方向（Ｚ−方向）に分極されたもの２枚を、第３
図の分極方向を同じにしたものと、第５図に示す
分極方向を逆〔互いに（＋）電極側に分極する〕
とした場合について計算機シユミレーシヨンした
共振周波数、振動モードについて説明する。 The piezoelectric elements are rectangular in shape, 20 mm in the X-direction, 3 mm in the Y-direction, and 1 mm in the Z-direction, and are polarized in the thickness direction (Z-direction).
The polarization direction shown in the figure is the same, and the polarization direction shown in Figure 5 is opposite [mutually polarized toward the (+) electrode side]
The resonant frequency and vibration mode simulated by computer will be explained in the following case.
第３図は分極方向を同じにした場合の入力アド
ミタンスの周波数を示したもので、17.0KHzと
87.5KHzに共振点が現われる。そして、17.0KHz
における振動モードは第４図ａのように、曲げ振
動の第１次モードであることを示しており、
87.5KHzにおける振動モードは第４図ｂのよう
に、第３次の曲げモードとなつている。 Figure 3 shows the input admittance frequency when the polarization direction is the same, which is 17.0KHz.
A resonance point appears at 87.5KHz. And 17.0KHz
The vibration mode in is the first mode of bending vibration, as shown in Figure 4a.
The vibration mode at 87.5KHz is the third-order bending mode, as shown in Figure 4b.
一方、第５図の分極方向を逆にした場合には、
第６図に示すように85.5KHzに共振点が現われ、
第３図に示したものと異なる。ａに示すものは変
位していない状態であり、ｂにおいては、85.5K
Hzにおいて、Ｚ−方向（厚み方向）の第１次厚み
振動モードであることがわかる。 On the other hand, if the polarization direction in Figure 5 is reversed,
As shown in Figure 6, a resonance point appears at 85.5KHz,
This is different from the one shown in FIG. What is shown in a is a state without displacement, and in b, 85.5K
Hz, it can be seen that this is the first thickness vibration mode in the Z-direction (thickness direction).
尚、分極方向は第６図とは反対側に互いに
（−）電極側であつても同様である。 The polarization direction is the same even if the (-) electrodes are on the opposite side to that shown in FIG.
以上、説明したように、同一形状の圧電素子を
用いても、分極方向を変えることにより、異なる
振動モード、共振周波数を選ぶことが可能とな
る。 As described above, even if piezoelectric elements of the same shape are used, different vibration modes and resonance frequencies can be selected by changing the polarization direction.
第１図は従来の湿度センサーの断面図、第２図
は本発明に係る湿度センサーの一実施例を示す断
面図、第３図は本発明の分極方向を同方向とした
入力アドミタンスの周波数特性を表わす図、第４
図ａ，ｂは共に振動モードを表わす図、第５図は
本発明の分極方向を逆方向とした入力アドミタン
スの周波数特性を表わす図、第６図ａ，ｂはその
振動モードを表わす図である。
尚、図中１は圧電素子、２は（＋）電極、２′
は（−）電極、３，３′は吸湿部材である。
Fig. 1 is a sectional view of a conventional humidity sensor, Fig. 2 is a sectional view showing an embodiment of the humidity sensor according to the present invention, and Fig. 3 is a frequency characteristic of input admittance with the polarization direction of the present invention in the same direction. Diagram representing 4th
Figures a and b both represent the vibration modes, Figure 5 is a diagram representing the frequency characteristics of the input admittance with the polarization direction of the present invention in the opposite direction, and Figures 6 a and b are diagrams representing the vibration modes. . In the figure, 1 is a piezoelectric element, 2 is a (+) electrode, and 2'
is a (-) electrode, and 3 and 3' are moisture absorbing members.
Claims (1)
圧電素子１，１の反（＋）電極２側に接地された
（−）電極２′，２′を取付け、（−）電極２′，
２′の表面に夫々親水性高分子で形成した吸湿部
材３，３′を取付けたことを特徴とする湿温セン
サー。1 (+) electrode 2 is held between piezoelectric elements 1, 1, and grounded (-) electrodes 2', 2' are attached to the opposite (+) electrode 2 side of both piezoelectric elements 1, 1, and (-) electrode 2',
A humidity and temperature sensor characterized in that moisture absorbing members 3 and 3' each made of a hydrophilic polymer are attached to the surface of 2'.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5359684A JPS60198445A (en) | 1984-03-22 | 1984-03-22 | Humidity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5359684A JPS60198445A (en) | 1984-03-22 | 1984-03-22 | Humidity sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60198445A JPS60198445A (en) | 1985-10-07 |
| JPH0345782B2 true JPH0345782B2 (en) | 1991-07-12 |
Family
ID=12947258
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5359684A Granted JPS60198445A (en) | 1984-03-22 | 1984-03-22 | Humidity sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60198445A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007123537A1 (en) * | 2006-04-20 | 2007-11-01 | Dover Electronics, Inc. (Dba Vectron International) | Electro acoustic sensor for high pressure environments |
| JPWO2013161559A1 (en) * | 2012-04-24 | 2015-12-24 | 株式会社村田製作所 | Humidity sensor element and manufacturing method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS577538A (en) * | 1980-06-18 | 1982-01-14 | Agency Of Ind Science & Technol | Piezo-electric humidity sensor |
-
1984
- 1984-03-22 JP JP5359684A patent/JPS60198445A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS577538A (en) * | 1980-06-18 | 1982-01-14 | Agency Of Ind Science & Technol | Piezo-electric humidity sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60198445A (en) | 1985-10-07 |
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