JPH0114919Y2 - - Google Patents
Info
- Publication number
- JPH0114919Y2 JPH0114919Y2 JP1981144361U JP14436181U JPH0114919Y2 JP H0114919 Y2 JPH0114919 Y2 JP H0114919Y2 JP 1981144361 U JP1981144361 U JP 1981144361U JP 14436181 U JP14436181 U JP 14436181U JP H0114919 Y2 JPH0114919 Y2 JP H0114919Y2
- Authority
- JP
- Japan
- Prior art keywords
- ultrasonic
- piezoelectric element
- plate
- propagator
- element plate
- 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
Links
- 238000001514 detection method Methods 0.000 claims description 12
- 230000005284 excitation Effects 0.000 claims description 12
- 239000011347 resin Substances 0.000 claims description 10
- 229920005989 resin Polymers 0.000 claims description 10
- 238000010521 absorption reaction Methods 0.000 claims description 2
- 238000001179 sorption measurement Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 description 7
- 230000001902 propagating effect Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02845—Humidity, wetness
Landscapes
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Description
【考案の詳細な説明】
本考案は超音波（弾性波）の伝播特性を利用し
た湿度検知素子に関する。[Detailed Description of the Invention] The present invention relates to a humidity sensing element that utilizes the propagation characteristics of ultrasonic waves (elastic waves).
第４図には従来のこの種の湿度検知素子が示さ
れている。即ち、この湿度検知素子は、水分の吸
着、吸収により超音波減衰能が変化する超音波伝
播体としての吸水性樹脂フイルム１と、このフイ
ルム１の両側下面に固着されている励起用と検出
用の圧電素子板２，２′と、これら圧電素子板２，
２′の下面に直接固定されてこれら圧電素子板２，
２′を基台４上に支持している一対の支持材３，
３′とを備えている。 FIG. 4 shows a conventional humidity sensing element of this type. That is, this humidity sensing element includes a water-absorbing resin film 1 as an ultrasonic propagator whose ultrasonic attenuation ability changes due to adsorption and absorption of moisture, and excitation and detection films fixed to the lower surfaces of both sides of the film 1. piezoelectric element plates 2, 2', these piezoelectric element plates 2,
These piezoelectric element plates 2,
2′ on a base 4, a pair of supporting members 3,
3'.
かかる従来の湿度検知素子において、上述した
ように圧電素子板２，２′の下面を支持材３，
３′により直接支持した場合には、励起用圧電素
子板２にて励起された超音波が一方の支持材３、
基台４及び他方の支持材３′をも経由して検出用
圧電素子板２′に伝播するため、吸水性樹脂フイ
ルム１から減衰変化して検出用圧電素子板２′に
直接伝播する湿度検出用の超音波がその影響を受
けてしまい、正確な湿度を検知することができな
かつた。 In such a conventional humidity sensing element, as described above, the lower surface of the piezoelectric element plates 2, 2' is connected to the supporting material 3,
3', the ultrasonic waves excited by the excitation piezoelectric element plate 2 are directly supported by one of the supporting members 3,
Since the humidity is transmitted to the detection piezoelectric element plate 2' via the base 4 and the other supporting member 3', the humidity is attenuated and changed from the water-absorbing resin film 1 and directly propagated to the detection piezoelectric element plate 2'. The ultrasonic waves used for the test were affected by this, making it impossible to accurately detect humidity.
ところで、超音波は殆んどの物質内を伝播し得
るが、異種の物質間においては両者の音響インピ
ーダンスの差が大きい場合超音波の伝播効率が影
響を受ける。そこで、上記従来の湿度検知素子に
おいて、吸水性樹脂フイルム１の両端を支持材に
より支持することも考えられるが、この場合には
励起用圧電素子板２と支持材との距離がフイルム
１厚程度しか増加しないので減衰距離としては不
充分であるだけでなく伝播効率もそれほど小さく
ならず、このため、やはり超音波が支持材側に伝
播してしまう欠点が免がれない。 By the way, ultrasonic waves can propagate through most materials, but when there is a large difference in acoustic impedance between different types of materials, the propagation efficiency of ultrasonic waves is affected. Therefore, in the above-mentioned conventional humidity sensing element, it is possible to support both ends of the water-absorbing resin film 1 by supporting materials, but in this case, the distance between the excitation piezoelectric element plate 2 and the supporting material is about one film thickness. Since the attenuation distance only increases, the attenuation distance is insufficient, and the propagation efficiency is not so small, so the drawback that the ultrasonic waves propagate toward the supporting material is unavoidable.
本考案は上記した点に鑑みてなされたもので、
超音波伝播体から検出用圧電素子板に伝播してく
る湿度検出用の超音波が他経由から伝播してくる
超音波の影響を殆んど受けることがない湿度検知
素子を提供することを目的とする。 This idea was made in view of the above points,
It is an object of the present invention to provide a humidity sensing element in which ultrasonic waves for humidity detection propagating from an ultrasonic propagating body to a detection piezoelectric element plate are hardly affected by ultrasonic waves propagating from other channels. shall be.
以下、本考案の実施例を図面を参照して説明す
る。 Embodiments of the present invention will be described below with reference to the drawings.
第１図及び第２図には本考案に係る湿度検知素
子が示され、この湿度検知素子は超音波伝播体と
しての吸水性樹脂フイルム５と、このフイルム５
の下面に固着されている励起用と検出用の圧電素
子板２，２′と、フイルム５を基台４上に支持し
ている一対の支持部材６，６′とを備えている。 1 and 2 show a humidity sensing element according to the present invention, and this humidity sensing element includes a water-absorbing resin film 5 as an ultrasonic wave propagator, and this film 5.
The device includes piezoelectric element plates 2, 2' for excitation and detection fixed to the lower surface of the device, and a pair of supporting members 6, 6' supporting the film 5 on the base 4.
上記吸水性樹脂フイルム５は従来よりも長手方
向に大きく形成され、即ちその両端が両圧電素子
板２，２′から離れる方向に延長されている。 The water-absorbing resin film 5 is formed to be larger in the longitudinal direction than conventional ones, that is, both ends thereof are extended in a direction away from both piezoelectric element plates 2, 2'.
上記一対の支持部材６，６′は、断面Ｌ字状に
形成された板状ばね部材から成り、上記吸水性樹
脂フイルム５に張力を付与した状態で該フイルム
５の両端を支持している。 The pair of support members 6, 6' are made of plate-like spring members having an L-shaped cross section, and support both ends of the water-absorbing resin film 5 while applying tension to the film.
次に、本考案の湿度検知素子の動作を説明す
る。即ち、励起用圧電素子板２に電圧を印加して
超音波を発生させると、この励起された超音波は
フイルム５を伝播して直接検出用圧電素子板２′
に達するが、その一部は支持部材６、基台４及び
支持部材６′を経由して検出用圧電素子板２′に達
する。 Next, the operation of the humidity sensing element of the present invention will be explained. That is, when a voltage is applied to the excitation piezoelectric element plate 2 to generate ultrasonic waves, the excited ultrasonic waves propagate through the film 5 and directly reach the detection piezoelectric element plate 2'.
A part of it reaches the detection piezoelectric element plate 2' via the support member 6, the base 4, and the support member 6'.
ところが、上述したようにフイルム５の端部を
圧電素子板２から離れる方向に延長し、圧電素子
板２と支持部材６との間の距離を大きくした場合
フイルム５の延長部と支持部材６との音響インピ
ーダンスの差が大きくなり、両者の伝播効率が極
めて小さくなる上に両者間において超音波を減衰
するための距離を充分にとることができる。従つ
て支持部材６，６′及び基台４を経由する超音波
は検出用圧電素子板２′に達するまでに極めて微
弱になるので、検出用圧電素子板２′の出力に殆
んど影響を与えることがない。 However, as described above, when the end of the film 5 is extended in the direction away from the piezoelectric element plate 2 and the distance between the piezoelectric element plate 2 and the support member 6 is increased, the extended part of the film 5 and the support member 6 are The difference in acoustic impedance between the two becomes large, the propagation efficiency between the two becomes extremely small, and a sufficient distance can be provided between the two to attenuate the ultrasonic waves. Therefore, the ultrasonic waves passing through the support members 6, 6' and the base 4 become extremely weak by the time they reach the detection piezoelectric element plate 2', and therefore have almost no effect on the output of the detection piezoelectric element plate 2'. I have nothing to give.
ところで、吸水性樹脂薄板若しくはフイルムの
如き超音波伝播体を伝播する超音波は、伝播体に
少々の撓みがあつても殆んど影響を受けないが、
鋭角で極端な撓みがある場合には影響を受ける。
ところが、本考案の湿度検知素子は、上述したよ
うに弾性を有する支持部材６によりフイルム５を
張力を付与した状態で支持したので、フイルム５
に撓みが生じるのを有効に防止でき、又若し極端
な撓みが生じた場合にはそれを吸収することがで
き、従つて、更に正確な湿度に関する情報を得る
ことができる。 By the way, ultrasonic waves propagating through an ultrasonic propagating body such as a water-absorbing resin thin plate or film are hardly affected even if the propagating body is slightly bent.
It is affected by sharp angles and extreme deflections.
However, in the humidity sensing element of the present invention, since the film 5 is supported under tension by the elastic support member 6 as described above, the film 5
It is possible to effectively prevent deflection from occurring, and if extreme deflection occurs, it can be absorbed, and therefore more accurate information regarding humidity can be obtained.
第３図には本考案の他の実施例が示されてい
る。即ち、この実施例では、吸水性樹脂フイルム
５の励起用圧電素子板２側端部のみを弾性を有す
る支持部材６により支持し、他端を弾性を有しな
い支持部材７により支持した例が示されている。
勿論上記フイルム５は一定の張力を付与された状
態で支持されている。従つて、この実施例でも上
記したと全く同一の作用、効果を得ることがで
き、またフイルム５の他端を弾性を有しない支持
部材により支持したことから、湿度検知素子の組
み立てが容易になるという利点がある。 Another embodiment of the invention is shown in FIG. That is, this embodiment shows an example in which only the end portion of the water-absorbing resin film 5 on the excitation piezoelectric element plate 2 side is supported by the support member 6 having elasticity, and the other end is supported by the support member 7 having no elasticity. has been done.
Of course, the film 5 is supported under a constant tension. Therefore, in this embodiment, the same functions and effects as described above can be obtained, and since the other end of the film 5 is supported by a non-elastic supporting member, the humidity sensing element can be easily assembled. There is an advantage.
以上説明したように本考案によれば、超音波伝
播体の励起用圧電素子板側の端部を延長し、該伝
播体の両端若しくはその延長端部のみを、伝播体
に張力を付与した状態で弾性を有する板状支持部
材にて支持したので、支持部材側を経由する超音
波の伝播効率を小さくし、かつこの超音波を減衰
することができ、しかも伝播体に撓みが発生する
のを効果的に防止することができ、従つて正確に
湿度を検知することができる。 As explained above, according to the present invention, the end of the ultrasonic propagation body on the excitation piezoelectric element plate side is extended, and tension is applied to the propagation body only at both ends of the propagation body or at the extended end. Since it is supported by an elastic plate-shaped supporting member, it is possible to reduce the propagation efficiency of ultrasonic waves passing through the supporting member side and attenuate the ultrasonic waves, and also to prevent the generation of deflection in the propagating body. It can be effectively prevented and therefore humidity can be detected accurately.
第１図及び第２図は本考案に係る湿度検知素子
の平面図と正面図、第３図は本考案の他の実施例
の一部省略正面図、第４図は従来の湿度検知素子
の正面図である。
１，５……吸水性樹脂フイルム、２……励起用
圧電素子板、２′……検出用圧電素子板、３，
３′……支持材、４……基台、６，６′……支持部
材、７……支持部材。尚、図中、同一符号は同一
部分を示す。
1 and 2 are a plan view and a front view of a humidity sensing element according to the present invention, FIG. 3 is a partially omitted front view of another embodiment of the present invention, and FIG. 4 is a diagram of a conventional humidity sensing element. It is a front view. 1, 5... Water-absorbing resin film, 2... Piezoelectric element plate for excitation, 2'... Piezoelectric element plate for detection, 3,
3'... Supporting material, 4... Base, 6, 6'... Supporting member, 7... Supporting member. In addition, in the figures, the same reference numerals indicate the same parts.
Claims (1)
吸着、吸収により超音波減衰能が変化する吸水性
樹脂薄板若しくはフイルムから成り、前記励起用
圧電素子板が取付けられる薄板状の超音波伝播体
と、該超音波伝播体に取付けられ、前記励起用圧
電素子板により励起されて前記超音波伝播体を伝
播してくる超音波を検出する検出用圧電素子板と
を備える湿度検知素子において、前記超音波伝播
体の励起用圧電素子板側の端部を延長し、該超音
波伝播体の両端若しくは前記延長端部を、前記超
音波伝播体に張力を付与した状態で弾性を有する
板状支持部材にて支持したことを特徴とする湿度
検知素子。 A thin plate-shaped ultrasonic propagator to which the excitation piezoelectric element plate is attached, which is composed of an excitation piezoelectric element plate that excites ultrasonic waves, and a water-absorbing resin thin plate or film whose ultrasonic attenuation ability changes due to adsorption and absorption of moisture. and a detection piezoelectric element plate that is attached to the ultrasonic propagation body and detects ultrasonic waves that are excited by the excitation piezoelectric element plate and propagate through the ultrasonic propagation body, the humidity sensing element comprising: An elastic plate-shaped support that extends the end of the ultrasonic propagator on the side of the excitation piezoelectric element plate, and supports both ends of the ultrasonic propagator or the extended end with tension applied to the ultrasonic propagator. A humidity sensing element characterized in that it is supported by a member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14436181U JPS5847761U (en) | 1981-09-29 | 1981-09-29 | Humidity sensing element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14436181U JPS5847761U (en) | 1981-09-29 | 1981-09-29 | Humidity sensing element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5847761U JPS5847761U (en) | 1983-03-31 |
| JPH0114919Y2 true JPH0114919Y2 (en) | 1989-05-02 |
Family
ID=29937325
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14436181U Granted JPS5847761U (en) | 1981-09-29 | 1981-09-29 | Humidity sensing element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5847761U (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52106787A (en) * | 1976-03-03 | 1977-09-07 | Mitsubishi Electric Corp | Gas and humidity detection element |
-
1981
- 1981-09-29 JP JP14436181U patent/JPS5847761U/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52106787A (en) * | 1976-03-03 | 1977-09-07 | Mitsubishi Electric Corp | Gas and humidity detection element |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5847761U (en) | 1983-03-31 |
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