JPH05273066A - Pressure sensor - Google Patents
Pressure sensorInfo
- Publication number
- JPH05273066A JPH05273066A JP7123692A JP7123692A JPH05273066A JP H05273066 A JPH05273066 A JP H05273066A JP 7123692 A JP7123692 A JP 7123692A JP 7123692 A JP7123692 A JP 7123692A JP H05273066 A JPH05273066 A JP H05273066A
- Authority
- JP
- Japan
- Prior art keywords
- film
- magneto
- pressure
- magnetization
- light
- 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.)
- Withdrawn
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、液体または気体の圧力
変化を直線偏光の偏光面回転として検出する圧力センサ
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for detecting a pressure change of a liquid or a gas as rotation of a plane of polarization of linearly polarized light.
【０００２】[0002]
【従来の技術】従来より、光を用いて圧力を測定する方
法としては、以下の様なものが知られている。まず１つ
の方法は、圧力が加わると複屈折が変化する光弾性素子
と光フアイバによる伝送路を組み合わせたものであり、
圧力が加わることによる光の偏光状態の変化によって圧
力を検出するものである。また、もう１つの方法は、特
開昭６３−２０５５３４号公報に開示されている様に、
圧力によって永久磁石などの磁気源を変位させ、この変
位により生ずる磁界の変化を磁気光学素子でピックアッ
プし、磁気光学素子を通る光の直線偏光面の回転に変換
するものである。また、更に別の方法は、磁気光学素子
の磁化状態が歪みによって変化する性質、すなわち磁歪
の逆効果を利用して圧力を段階的に測定するものであ
る。2. Description of the Related Art Conventionally, the following methods have been known as methods for measuring pressure using light. First, one method is a combination of a photoelastic element whose birefringence changes when pressure is applied and a transmission line using an optical fiber,
The pressure is detected by the change of the polarization state of light due to the application of pressure. Another method is disclosed in JP-A-63-205534,
A magnetic source such as a permanent magnet is displaced by pressure, and a change in magnetic field caused by this displacement is picked up by a magneto-optical element and converted into rotation of a linear polarization plane of light passing through the magneto-optical element. Still another method is to measure the pressure stepwise by utilizing the property that the magnetization state of the magneto-optical element changes due to strain, that is, the inverse effect of magnetostriction.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記の
従来の方法のうち、複屈折の変化を用いる方法と、磁歪
の逆効果を用いる方法においては、結晶の機械的歪みを
介して光弾性素子の複屈折を変化させたり、磁気光学素
子の磁化状態を変化させたりしているため、感度と機械
的強度の両立が困難であるという問題点がある。However, among the above-mentioned conventional methods, in the method using the change of birefringence and the method using the inverse effect of magnetostriction, the photoelastic element of the photoelastic element is mediated by the mechanical strain of the crystal. Since the birefringence is changed or the magnetization state of the magneto-optical element is changed, it is difficult to achieve both sensitivity and mechanical strength.
【０００４】また、永久磁石を変位させる方法において
は、この永久磁石を変位させるための機械的な構造が必
要となるため、圧力の検出装置の構成が複雑化するとい
う問題点がある。従って、本発明は上述した課題に鑑み
てなされたものであり、その目的とするところは、簡単
な構成で、検出感度の向上と機械的強度の向上が図れる
様な圧力センサを提供することにある。Further, in the method of displacing the permanent magnet, a mechanical structure for displacing the permanent magnet is required, which causes a problem that the structure of the pressure detecting device becomes complicated. Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a pressure sensor with a simple configuration that can improve detection sensitivity and mechanical strength. is there.
【０００５】[0005]
【課題を解決するための手段】上述の課題を解決し、目
的を達成するために、本発明の圧力センサは、圧力によ
り変形する部材と、該部材の変形に応じて変形する磁気
光学膜と、該磁気光学膜の変形を直線偏光の偏光面回転
として検出する検出手段とを具備することを特徴として
いる。In order to solve the above-mentioned problems and to achieve the object, a pressure sensor of the present invention comprises a member which is deformed by pressure and a magneto-optical film which is deformed according to the deformation of the member. And a detection means for detecting the deformation of the magneto-optical film as rotation of the polarization plane of linearly polarized light.
【０００６】また、この発明に係わる圧力センサにおい
て、前記磁気光学膜は、ダイアフラム状に形成された前
記部材上に配設されており、前記検出手段は、前記磁気
光学膜を透過した光の偏光面の回転角を検出することを
特徴としている。Further, in the pressure sensor according to the present invention, the magneto-optical film is disposed on the member formed in a diaphragm shape, and the detecting means polarizes the light transmitted through the magneto-optical film. The feature is that the rotation angle of the surface is detected.
【０００７】[0007]
【作用】以上の様に、この発明に係わる圧力センサは構
成されているので、圧力により変形し易い部分と機械的
強度の高い部分を合わせ持つダイアフラム状に形成され
た部材の表面に、磁気光学素子の薄膜を形成し、ダイア
フラムの膜部分の変形を磁気光学素子の膜で検出するこ
とにより、簡単な構成で、検出感度の向上と機械的強度
の向上を両立させた圧力センサを実現することができ
る。As described above, since the pressure sensor according to the present invention is constructed, the magneto-optical element is formed on the surface of the member formed in the shape of a diaphragm having both a portion easily deformed by pressure and a portion having high mechanical strength. By forming a thin film of the element and detecting the deformation of the diaphragm film portion with the film of the magneto-optical element, it is possible to realize a pressure sensor that has both a simple structure and improved detection sensitivity and mechanical strength. You can
【０００８】[0008]
【実施例】以下、本発明の好適な一実施例について、添
付図面を参照して詳細に説明する。まず、一実施例の圧
力センサについて説明する前に、磁歪を用いて圧力を検
出する方法について説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. First, before describing the pressure sensor of one embodiment, a method of detecting pressure using magnetostriction will be described.
【０００９】この磁歪を用いて圧力を検出する方法は、
磁気光学素子の磁化状態が加えられた応力によって変化
する性質を用いるものである。一般的に磁気光学素子
は、磁化することにより磁化方向に伸び縮みし、逆に伸
び縮みさせる（応力を加える）ことにより磁化の方向が
変化する性質を有している。磁化した時に、磁化方向に
伸びるものが、磁歪定数が正のものであり、逆に磁化方
向に縮むものが磁歪定数が負のものである。The method of detecting pressure using this magnetostriction is as follows:
It uses the property that the magnetized state of the magneto-optical element changes depending on the applied stress. In general, a magneto-optical element has a property that when magnetized, it expands and contracts in the direction of magnetization, and conversely, when it expands and contracts (applies stress), the direction of magnetization changes. When magnetized, those that extend in the magnetization direction have a positive magnetostriction constant, and those that contract in the magnetization direction conversely have a negative magnetostriction constant.
【００１０】例えば、磁歪定数が正の磁気光学素子に、
図１（ａ）に示した方向に圧縮応力を加えた場合、磁化
容易軸は図１（ａ）に示した様な応力と平行な方向から
図１（ｂ）に示した様な応力と垂直な方向に変化する。
ただし、どの程度の圧縮応力を加えた時に磁化容易軸の
方向が変化するかという応力の閾値は、磁気光学素子の
種類により異なる。また、逆に引っ張り応力を加えた場
合には、磁化容易軸は図１（ａ）に示した状態から変化
しない。For example, in a magneto-optical element having a positive magnetostriction constant,
When compressive stress is applied in the direction shown in FIG. 1 (a), the easy axis of magnetization is perpendicular to the stress shown in FIG. 1 (b) from the direction parallel to the stress shown in FIG. 1 (a). Change in the right direction.
However, the threshold value of the stress, which is how much compressive stress is applied to change the direction of the easy axis of magnetization, differs depending on the type of the magneto-optical element. On the contrary, when a tensile stress is applied, the easy axis of magnetization does not change from the state shown in FIG.
【００１１】従って、応力の働く方向に磁場をかけた場
合、その応力の大きさ（磁歪定数が正の磁気光学素子の
場合には圧縮応力の大きさであり、磁歪定数が負の磁気
光学素子の場合には引っ張り応力の大きさである）によ
って、磁気光学素子に生ずる応力方向の磁化が変化する
こととなる。ここで、磁気光学素子は、透過した光の偏
光面の角度を変化させる性質を有している。そして、偏
光面の回転角は磁化の関数であるから、磁気光学素子に
直線偏光の光を透過させ、その偏光面の回転角を測定す
ることにより、磁気光学素子の磁化の大きさを測定する
ことができる。まとめると、磁気光学素子を透過した光
の偏光面の回転角を測定することにより、磁気光学素子
の磁化の大きさを知ることができ、この磁化の大きさか
ら、更に磁気光学素子に加わっている応力の大きさを知
ることができるわけである。Accordingly, when a magnetic field is applied in the direction in which the stress acts, the magnitude of the stress (in the case of a magneto-optical element having a positive magnetostriction constant, the magnitude of compressive stress, and the magneto-optical element having a negative magnetostriction constant). In that case, the magnitude of the tensile stress) changes the magnetization in the stress direction generated in the magneto-optical element. Here, the magneto-optical element has the property of changing the angle of the polarization plane of the transmitted light. Since the rotation angle of the plane of polarization is a function of magnetization, linearly polarized light is transmitted through the magneto-optical element, and the rotation angle of the plane of polarization is measured to measure the magnitude of magnetization of the magneto-optical element. be able to. In summary, by measuring the rotation angle of the plane of polarization of the light transmitted through the magneto-optical element, it is possible to know the magnitude of the magnetization of the magneto-optical element. It is possible to know the magnitude of the existing stress.
【００１２】次に上述した原理に従って、液体あるいは
気体の圧力を測定する圧力センサについて図２を参照し
て説明する。圧力センサ１２は、ダイアフラム状に形成
されたベース部材１４と、このベース部材１４の膜状部
分１４ａの表面に形成された磁気光学材料から成る薄膜
１６（以下磁気光学膜と呼ぶ）と、この磁気光学膜１６
に直線偏光の光を照射するための照射装置１８と、磁気
光学膜１６を透過した光の偏光面の回転角を測定するた
めの検出装置２０とから概略構成されている。Next, a pressure sensor for measuring the pressure of liquid or gas according to the above-mentioned principle will be described with reference to FIG. The pressure sensor 12 includes a base member 14 formed in a diaphragm shape, a thin film 16 (hereinafter referred to as a magneto-optical film) made of a magneto-optical material formed on the surface of the film-shaped portion 14a of the base member 14, and the magnetic member. Optical film 16
An irradiation device 18 for irradiating linearly polarized light and a detection device 20 for measuring the rotation angle of the polarization plane of the light transmitted through the magneto-optical film 16 are roughly configured.
【００１３】ベース部材１４は、測定する圧力の大きさ
に対応した大きさに形成されており、また、使用する材
料も、圧力の大きさに応じて、ステンレス、アルミニウ
ム等が用いられる。磁気光学膜１６は、その磁化容易軸
がベース部材１４の膜状部分１４ａに対して垂直方向を
向く様に形成されており、材料としては、Ｄｙ3 Ｆｅ 5
Ｏ12が用いられている。なお、ベース部材１４の近傍に
は、永久磁石等（不図示）が配置されており、磁気光学
膜１６には、図２（ａ）に矢印で示した方向に磁界がか
けられている。The base member 14 has a magnitude of pressure to be measured.
It is formed in a size corresponding to
Depending on the amount of pressure, stainless steel or aluminum
Are used. The magneto-optical film 16 has an axis of easy magnetization.
Is perpendicular to the membranous portion 14a of the base member 14.
It is formed to face, and the material is Dy3 Fe Five
O12Is used. In the vicinity of the base member 14,
Is equipped with a permanent magnet etc. (not shown).
A magnetic field is applied to the film 16 in the direction indicated by the arrow in FIG.
It has been burned.
【００１４】図２（ａ）に示した状態においては、圧力
センサ１２には圧力が加わっておらず、磁気光学膜の磁
化容易軸の方向は磁界の方向と直交している。そのた
め、磁気光学膜１６に生ずる、磁界と平行な方向の磁化
は小さい。この状態において、照射装置１８から照射さ
れる直線偏光の光を、磁気光学膜１６に透過させた場合
には、光の入射方向の磁気光学素子の磁化が小さいの
で、光の偏光面の回転角も図２（ａ）にθで示した様に
小さい。In the state shown in FIG. 2A, no pressure is applied to the pressure sensor 12, and the direction of the easy axis of magnetization of the magneto-optical film is orthogonal to the direction of the magnetic field. Therefore, the magnetization generated in the magneto-optical film 16 in the direction parallel to the magnetic field is small. In this state, when the linearly polarized light emitted from the irradiation device 18 is transmitted through the magneto-optical film 16, since the magnetization of the magneto-optical element in the incident direction of the light is small, the rotation angle of the plane of polarization of the light. Is small as indicated by θ in FIG.
【００１５】一方、図２（ｂ）に矢印Ｐで示した様に、
圧力センサ１２に圧力が加わった場合には、ベース部材
１４は図示した様に変形し、磁気光学膜１６には圧縮応
力が働く。このとき働く圧縮応力が一定の閾値応力を越
えていた場合には、磁気光学膜１６を構成するＤｙ3 Ｆ
ｅ5 Ｏ12は、負の磁歪定数を持っているため、圧縮応力
により、磁気光学膜１６の磁化容易軸は、磁気光学膜１
６の面内方向を向くこととなる。その結果、磁気光学膜
１６の磁化容易軸と磁界の方向は平行となり、磁気光学
膜の面内方向の磁化は大きくなる。従って、磁気光学膜
１６を透過する光の偏光面の回転角も、図２（ｂ）にφ
で示した様に大きくなる。On the other hand, as shown by an arrow P in FIG.
When pressure is applied to the pressure sensor 12, the base member 14 is deformed as shown in the drawing, and compressive stress acts on the magneto-optical film 16. If the compressive stress acting at this time exceeds a certain threshold stress, Dy 3 F forming the magneto-optical film 16 is formed.
Since e 5 O 12 has a negative magnetostriction constant, the easy axis of magnetization of the magneto-optical film 16 is compressed by the compressive stress.
6 will be directed in the in-plane direction. As a result, the easy axis of magnetization of the magneto-optical film 16 and the direction of the magnetic field become parallel, and the in-plane magnetization of the magneto-optical film becomes large. Therefore, the rotation angle of the polarization plane of the light transmitted through the magneto-optical film 16 is also φ in FIG.
It becomes large as shown in.
【００１６】このように、ある一定の閾値圧力（磁気光
学膜１６に閾値応力を発生させる様な圧力）を越える圧
力が圧力センサ１２に加わった場合には、磁気光学膜１
６の磁化容易軸の方向が９０°変化し、それに伴って磁
気光学素子を透過する光の偏光面の回転角も変化する。
そのため、この回転角の変化を測定することによって、
圧力センサ１２に加わる圧力が一定の閾値圧力を越えた
か否かを検出することができる。In this way, when a pressure exceeding a certain threshold pressure (pressure that causes threshold stress in the magneto-optical film 16) is applied to the pressure sensor 12, the magneto-optical film 1
The direction of the easy axis of magnetization 6 changes by 90 °, and the rotation angle of the plane of polarization of the light passing through the magneto-optical element also changes accordingly.
Therefore, by measuring the change in this rotation angle,
It is possible to detect whether or not the pressure applied to the pressure sensor 12 exceeds a certain threshold pressure.
【００１７】磁化容易軸の方向が変化する閾値圧力は、
磁気光学膜１６の磁歪定数とベース部材１４の変形量で
決まる。そのため、ベース部材１４の膜状部分１４ａの
厚さを変化させる等の操作を行って、圧力の大きさとベ
ース部材１４の変形量との関係を変化させることによ
り、検出する閾値圧力の値を変化させることができる。
なお、上記の様な圧力センサ１２を制作する方法として
は、以下の様な方法が考えられる。まず、ベース部材１
４としてのシリコン単結晶に膜状部分１４ａをマイクロ
マシニングの手法を用いて形成した後、磁気光学膜１６
としてのＤｙ3Ｆｅ5 Ｏ12の膜をスパッタ法によって制
作する。その他の製膜法として、ＬＥＰ法・ＣＤＶ法を
用いても良い。この様にして制作する磁気光学膜１６
は、製作条件を制御することによって、磁化容易軸の方
向を制御することができる。磁気光学膜を形成した後、
エッチング等の手法を用いて光導波路を形成する。The threshold pressure at which the direction of the easy axis of magnetization changes is
It is determined by the magnetostriction constant of the magneto-optical film 16 and the amount of deformation of the base member 14. Therefore, the value of the threshold pressure to be detected is changed by performing an operation such as changing the thickness of the film-shaped portion 14a of the base member 14 to change the relationship between the magnitude of the pressure and the deformation amount of the base member 14. Can be made
The following method can be considered as a method of producing the pressure sensor 12 as described above. First, the base member 1
After forming the film-like portion 14a on the silicon single crystal as No. 4 by using the micromachining method, the magneto-optical film 16 is formed.
A film of Dy 3 Fe 5 O 12 is prepared by the sputtering method. As another film forming method, the LEP method / CDV method may be used. Magneto-optical film 16 produced in this way
Can control the direction of the easy axis of magnetization by controlling the manufacturing conditions. After forming the magneto-optical film,
An optical waveguide is formed using a technique such as etching.
【００１８】以上説明した様に、一実施例の圧力センサ
においては、ダイアフラム構造のベース部材と、このベ
ース部材の膜状部分に形成された磁気光学膜を組み合わ
せることにより、応力に対する磁気光学膜の変形を大き
くとることが可能でありながら、機械的強度も確保する
ことが実現されている。すなわち、従来の様に、磁気光
学素子そのものに機械的強度をも受け持たせてる場合に
は、機械的強度と検出感度とを両立させることは困難で
あったが、一実施例によれば、機械的強度と検出感度と
を両立させた圧力センサを提供することができる。As described above, in the pressure sensor of one embodiment, by combining the base member having the diaphragm structure and the magneto-optical film formed on the film-shaped portion of the base member, the magneto-optical film against the stress is formed. While it is possible to take a large amount of deformation, it has been realized that the mechanical strength is secured. That is, as in the conventional case, when the magneto-optical element itself is also responsible for mechanical strength, it was difficult to achieve both mechanical strength and detection sensitivity, but according to one embodiment, A pressure sensor having both mechanical strength and detection sensitivity can be provided.
【００１９】[0019]
【発明の効果】以上説明した様に、本発明の圧力センサ
によれば、圧力により変形し易い部分と機械的強度の高
い部分を合わせ持つダイアフラム状に形成された部材の
表面に、磁気光学素子の薄膜を形成し、ダイアフラムの
膜部分の変形を磁気光学素子の膜で検出することによ
り、簡単な構成で、検出感度の向上と機械的強度の向上
を両立させた圧力センサを実現することができる。As described above, according to the pressure sensor of the present invention, the magneto-optical element is formed on the surface of the member formed in the shape of a diaphragm having both the portion easily deformed by pressure and the portion having high mechanical strength. By forming the thin film of and the deformation of the diaphragm film part is detected by the film of the magneto-optical element, it is possible to realize a pressure sensor that has both improved detection sensitivity and improved mechanical strength with a simple configuration. it can.
【図１】磁気光学素子に働く応力の方向と磁化容易軸の
方向との関係を示した図である。FIG. 1 is a diagram showing a relationship between a direction of stress acting on a magneto-optical element and a direction of an easy axis of magnetization.
【図２】圧力センサに圧力が加わっていない状態と、圧
力が加わったときの状態の変化を示した図である。FIG. 2 is a diagram showing a state in which pressure is not applied to the pressure sensor and a change in state when pressure is applied.
１２ 圧力センサ １４ ベース部材 １６ 磁気光学膜 １８ 照射装置 ２０ 検出装置 12 pressure sensor 14 base member 16 magneto-optical film 18 irradiation device 20 detection device
Claims (2)
する検出手段とを具備することを特徴とする圧力セン
サ。1. A member comprising: a member that is deformed by pressure; a magneto-optical film that is deformed according to the deformation of the member; and a detection unit that detects the deformation of the magneto-optical film as a polarization plane rotation of linearly polarized light. Characteristic pressure sensor.
成された前記部材上に配設されており、前記検出手段
は、前記磁気光学膜を透過した光の偏光面の回転角を検
出することを特徴とする請求項１に記載の圧力センサ。2. The magneto-optical film is disposed on the member formed in a diaphragm shape, and the detection means detects a rotation angle of a polarization plane of light transmitted through the magneto-optical film. The pressure sensor according to claim 1, wherein:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7123692A JPH05273066A (en) | 1992-03-27 | 1992-03-27 | Pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7123692A JPH05273066A (en) | 1992-03-27 | 1992-03-27 | Pressure sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05273066A true JPH05273066A (en) | 1993-10-22 |
Family
ID=13454863
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7123692A Withdrawn JPH05273066A (en) | 1992-03-27 | 1992-03-27 | Pressure sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05273066A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006062275A1 (en) * | 2004-12-08 | 2006-06-15 | Mdt Co., Ltd. | Variable inductor type mems pressure sensor using magnetostrictive effect |
| JP2012176294A (en) * | 2012-06-19 | 2012-09-13 | Toshiba Corp | Blood pressure sensor |
-
1992
- 1992-03-27 JP JP7123692A patent/JPH05273066A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006062275A1 (en) * | 2004-12-08 | 2006-06-15 | Mdt Co., Ltd. | Variable inductor type mems pressure sensor using magnetostrictive effect |
| JP2012176294A (en) * | 2012-06-19 | 2012-09-13 | Toshiba Corp | Blood pressure sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990608 |