JP2543566B2 - Analog type Faraday effect type optical position detector - Google Patents
Analog type Faraday effect type optical position detectorInfo
- Publication number
- JP2543566B2 JP2543566B2 JP63079958A JP7995888A JP2543566B2 JP 2543566 B2 JP2543566 B2 JP 2543566B2 JP 63079958 A JP63079958 A JP 63079958A JP 7995888 A JP7995888 A JP 7995888A JP 2543566 B2 JP2543566 B2 JP 2543566B2
- Authority
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- Prior art keywords
- optical element
- light
- faraday
- magnet
- faraday effect
- 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
- 230000003287 optical effect Effects 0.000 title claims description 38
- 230000000694 effects Effects 0.000 title claims description 10
- 238000005259 measurement Methods 0.000 claims description 18
- 238000001514 detection method Methods 0.000 claims description 17
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- 230000010287 polarization Effects 0.000 description 10
- 239000013307 optical fiber Substances 0.000 description 5
- 239000000428 dust Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- Optical Transform (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、光を用いた位置検出装置に関し、特に航空
機等の耐環境性を要求される装置に使用するもので、工
作機械や化学プラント等にも利用することが出来る。Description: TECHNICAL FIELD The present invention relates to a position detecting device using light, and is particularly used for a device such as an aircraft that is required to have environmental resistance, and is used for a machine tool or a chemical plant. It can also be used for etc.
従来のアナログ式光位置検出装置は第２図及び第３図
に示されるものが知られている。これは、光源１から射
出された測定光が光ファイバー２を通って検出端部６か
ら射出され、ミラー４によって反射され、別の光ファイ
バ５の検出端部６′に入射し、光ファイバ５を通って受
光器３によって受光されるようになっている。Known analog type optical position detecting devices are shown in FIG. 2 and FIG. This is because the measurement light emitted from the light source 1 passes through the optical fiber 2 and is emitted from the detection end 6 and is reflected by the mirror 4 and is incident on the detection end 6 ′ of another optical fiber 5 and the optical fiber 5 is emitted. It is adapted to be received by the light receiver 3 therethrough.
したがって、ミラー４と検出端部６、６′との距離が
変ると受光される光量が変化することになるので、この
光量変化がミラー４と検出端部６、６′の位置信号とな
る。一般には一定光量に制御された光源を用いて、検出
端部６、６′を固定しておき、ミラー４を被測定物に取
付けておくことにより、被測定物の位置変化を検出する
ことが出来る。Therefore, the amount of light received changes when the distance between the mirror 4 and the detection ends 6 and 6'changes, and this change in the amount of light becomes the position signal of the mirror 4 and the detection ends 6 and 6 '. Generally, by using a light source controlled to have a constant light amount, the detection ends 6 and 6'are fixed and the mirror 4 is attached to the object to be measured, so that the position change of the object to be measured can be detected. I can.
この場合、ミラー４と検出端部６、６′との距離と受
光器の検出光量との関係は第３図のようになる。In this case, the relationship between the distance between the mirror 4 and the detection ends 6 and 6'and the amount of light detected by the light receiver is as shown in FIG.
ミラー４の位置が零“0"のときは、検出端部６、６′
と接触した状態である。When the position of the mirror 4 is zero "0", the detection ends 6 and 6 '
Is in contact with.
しかしながら、このような従来の装置においては、検
出端部６、６′とミラー４との間に空間が存在するた
め、光を妨害する異物の付着、即ち塵埃や付着又は温度
変化に伴う結露の発生等が生じた場合、測定光がそれら
に妨害されて正確な位置検出が不可能となる欠点を有し
ていた。However, in such a conventional device, since there is a space between the detection end portions 6 and 6'and the mirror 4, foreign matter that interferes with light is adhered, that is, dust or adhesion or condensation caused by temperature change. In the case of occurrence, etc., there is a drawback that the measuring light is blocked by them and accurate position detection becomes impossible.
したがって、前記欠点を防止するために堅牢な防塵カ
バーを設けたり、測定前にアルコール等で検出端部やミ
ラーの表面を洗浄する等の作業が不可欠であった。その
ため、位置検出装置が大型化し、保持を行うにも多大な
労力を要していた。Therefore, it is indispensable to provide a robust dustproof cover in order to prevent the above-mentioned defects and to wash the detection end portion and the surface of the mirror with alcohol before the measurement. Therefore, the position detection device becomes large in size, and a great deal of labor is required to hold the position detection device.
本発明は、前記欠点を解決するために、前記洗浄作業
を必要とせず、且つ組立てが簡単で小型の光位置検出装
置を提供することを目的とするものである。SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact optical position detecting device which does not require the cleaning work and is easy to assemble to solve the above drawbacks.
本発明においては、ファラデー光学素子の一端面に偏
光子を、他端面に検光子を取り付けた棒状ファラデー光
学素子を例えば航空機の舵面制御用アクチュエータ等に
連動する筒状磁石の中に軸方向に相対変位可能に挿入す
ることにより、アクチュエータ等の位置を光学的に検出
するものである。即ち筒状磁石と棒状ファラデー光学素
子との相対的位置の変化により、棒状ファラデー光学素
子の中を通過する光の偏光面の回転角を外部空間を介す
ることなく光アナログ信号として取り出すようにしてあ
る。In the present invention, a rod-shaped Faraday optical element in which a polarizer is attached to one end face of the Faraday optical element and an analyzer is attached to the other end face thereof is axially arranged in a cylindrical magnet interlocked with, for example, an actuator for controlling the control surface of an aircraft. The position of the actuator or the like is optically detected by inserting it so as to be relatively displaceable. That is, the rotation angle of the polarization plane of the light passing through the rod-shaped Faraday optical element is extracted as an optical analog signal without passing through the external space by changing the relative position of the cylindrical magnet and the rod-shaped Faraday optical element. .
ファラデー光学素子は、磁界により、その中を通過す
る光の偏光面を回転させる性質（いわゆるファラデー効
果）を有する素子であり、この偏光面の回転角θＦは、
光の進行方向成分の磁界の強さHFと磁界が及び長さｌと
物性常数（ベルデ定数）Ｖとに比例し、次のように表わ
される。A Faraday optical element is an element having the property of rotating the polarization plane of light passing through it by a magnetic field (so-called Faraday effect), and the rotation angle θ F of this polarization plane is
The magnetic field strength H F of the light traveling direction component and the magnetic field are proportional to the length l and the physical property constant (Verdet constant) V, and are expressed as follows.
θＦ＝Ｖ・ｌ・HF したがって、磁界の強さが一定の場合、ファラデー光
学素子に影響を及ぼす磁界の長さｌが変ることにより、
θＦが変化する。そして、このθＦの変化を何等かの方
法によって検出することによりｌの移動量（変位）を検
出することが出来る。θ F = V · l · H F Therefore, when the magnetic field strength is constant, the length l of the magnetic field affecting the Faraday optical element changes,
θ F changes. Then, the movement amount (displacement) of l can be detected by detecting the change in θ F by some method.
本発明は、上記原理に基づき、光学的に位置の検出を
行うようにしたものである。The present invention is based on the above principle and is adapted to optically detect the position.
以下、本発明の実施例について説明する。 Examples of the present invention will be described below.
第１図は本発明実施例の概略説明図で、第１図（ａ）
は、その断面図、同図（ｂ）は第１図（ａ）における×
−×断面図である。FIG. 1 is a schematic explanatory view of an embodiment of the present invention, and FIG. 1 (a)
Is its cross-sectional view, and FIG. 1 (b) is x in FIG. 1 (a).
It is a cross-sectional view.
21は測定用の光源で、周知の制御手段を用いた光量の
安定したものが使用される。24は棒状のファラデー光学
素子で、光源側即ち測定光入射側の一端面24a（以下、
端部24aともいう）に偏光子23を、他端面24b（以下、端
部24bともいう）に検光子25を取り付けた丸棒状のもの
である。このファラデー光学素子24を例えば航空機の舵
面制御用アクチュエータ等に連動する筒状磁石の中に軸
方向に相対的に移動可能に挿入することにより、アクチ
ュエータ等の位置を光学的に検出するものである。即ち
筒状磁石と棒状ファラデー光学素子との相対変位により
ファラデー光学素子24の中を通る光の偏光面の回転角が
変化したとき、この変化に対応する信号を、外部空間を
介することなく光のアナログ信号として取り出すように
してある。第１図は、本発明の基本原理を示す説明であ
る。Reference numeral 21 denotes a light source for measurement, which has a stable light quantity using a well-known control means. 24 is a rod-shaped Faraday optical element, one end surface 24a on the light source side, that is, the measurement light incident side (hereinafter,
A polarizer 23 is attached to the end portion 24a), and an analyzer 25 is attached to the other end surface 24b (hereinafter, also referred to as the end portion 24b). By inserting this Faraday optical element 24 into a cylindrical magnet that is interlocked with, for example, an actuator for controlling the control surface of an aircraft so as to be relatively movable in the axial direction, the position of the actuator or the like can be optically detected. is there. That is, when the rotation angle of the plane of polarization of the light passing through the Faraday optical element 24 changes due to the relative displacement of the cylindrical magnet and the rod-shaped Faraday optical element, a signal corresponding to this change is transmitted to the light without passing through the external space. It is taken out as an analog signal. FIG. 1 is an explanation showing the basic principle of the present invention.
ファラデー光学素子は、磁界により、その中を通過す
る光の偏光面を回転させる性質（いわゆるファラデー効
果）を有する素子であり、この偏光面の回転角θＦは、
磁界の強さHrと磁界が及ぶ長さｌと物性常数（ベルデ定
数）Ｖとに比例し、次のように表わされる。A Faraday optical element is an element having the property of rotating the polarization plane of light passing through it by a magnetic field (so-called Faraday effect), and the rotation angle θ F of this polarization plane is
It is proportional to the strength H r of the magnetic field, the length 1 of the magnetic field and the physical property constant (Verdet constant) V, and is expressed as follows.
θＦ＝Ｖ・ｌ・Hr したがって、磁界の強さが一定の場合、ファラデー光
学素子に影響を及ぼす磁界の長さｌが変る端部24aに偏
光子23を設け、受光器側即ち測定光射出側端部24bに検
出子25を設ける。この検光子25と前記偏光子23とは同じ
ものであるが、これらは互いに偏光面が90゜の直交状態
に配置される。27は受光器で、ファラデー光学素子から
検光子を通過して出て来た光量を測定するものである。
22、26は光源21からの測定光を導く光ファイバ又はこれ
と等価の光導体で、それぞれ光源側とファラデー光学素
子の測定光入射側端部24aにおる偏光子23及び測定光射
出側端部24bにある検光子25の受光器側とに接続されて
いる。θ F = V · l · H r Therefore, when the strength of the magnetic field is constant, the polarizer 23 is provided at the end 24a where the length l of the magnetic field affecting the Faraday optical element changes, and the light receiver side, that is, the measurement light A detector 25 is provided at the emitting end 24b. The analyzer 25 and the polarizer 23 are the same, but they are arranged so that their planes of polarization are 90 ° orthogonal to each other. Reference numeral 27 denotes a light receiver, which measures the amount of light emitted from the Faraday optical element through the analyzer.
Reference numerals 22 and 26 denote optical fibers that guide the measurement light from the light source 21 or equivalent optical conductors, and the polarizer 23 and the measurement light emission side end portions of the light source side and the measurement light incident side end portion 24a of the Faraday optical element, respectively. It is connected to the light receiver side of the analyzer 25 in 24b.
筒状磁石28はフェライトコアー等により成形された筒
状の永久磁石で、その中空部に前記棒状のファラデー光
学素子が軸方向に沿って相対的に移動するように挿入さ
れている。磁石の極性は図のように測定光入射側をＳ
極、測定光射出側をＮ極とした場合、磁石中空部におけ
る磁界の方向は矢印Ｈで示す方向となる。The tubular magnet 28 is a tubular permanent magnet formed by a ferrite core or the like, and the rod-shaped Faraday optical element is inserted into the hollow portion of the permanent magnet so as to move relatively along the axial direction. The polarity of the magnet is S on the measurement light incident side as shown in the figure.
When the pole and the measurement light emitting side are N poles, the direction of the magnetic field in the hollow portion of the magnet is the direction indicated by the arrow H.
磁石28の中空部における磁界の強さは中空部内部にお
いてはほぼ一様に分布しており、磁石28が半径方向には
多少動いても、回転しても中に挿入されているファラデ
ー光学素子のファラデー効果には影響がない。The strength of the magnetic field in the hollow portion of the magnet 28 is almost evenly distributed inside the hollow portion, and the Faraday optical element is inserted even if the magnet 28 moves slightly in the radial direction or rotates. It does not affect the Faraday effect of.
また、本実施例では、筒状磁石28の発生磁界を使用温
度範囲内において十分に強くし、筒状磁石28内に挿入さ
れるファラデー光学素子24を確実に磁気飽和させるよう
にしている。これによって、温度の変化に基づく光の出
力変化を小さく抑えることができる。Further, in this embodiment, the magnetic field generated by the tubular magnet 28 is made sufficiently strong within the operating temperature range so that the Faraday optical element 24 inserted in the tubular magnet 28 is magnetically saturated. As a result, it is possible to suppress a change in light output due to a change in temperature.
以上の構成による作用を説明する。 The operation of the above configuration will be described.
筒状磁石28は、位置検出を必要とする部材、例えば航
空機の舵面用アクチュエータに連動して図面上左右方向
即ち磁石の軸線方向に移動するようになっているものと
する。It is assumed that the tubular magnet 28 moves in the left-right direction in the drawing, that is, in the axial direction of the magnet, in conjunction with a member that requires position detection, for example, a control surface actuator of an aircraft.
光源21から出た光は、光ファイバ22に導かれて偏光子
23を通過する時に直線偏光となり、この直線偏光がファ
ラデー光学素子24に入射する。アクチュエータ等に連動
して、筒状磁石28が例えば図面上で右方向に移動したと
すれば、ファラデー光学素子24に入謝した直線偏光は、
ファラデー光学素子24が磁石の中空部に挿入された量
（長さ）に応じた偏光面の回転を生ずる。The light emitted from the light source 21 is guided to the optical fiber 22 and is a polarizer.
When passing through 23, it becomes linearly polarized light, and this linearly polarized light is incident on the Faraday optical element 24. If the cylindrical magnet 28 is moved to the right in the drawing in conjunction with the actuator or the like, the linearly polarized light that has entered the Faraday optical element 24 is
The Faraday optical element 24 causes the polarization plane to rotate depending on the amount (length) of the magnet inserted into the hollow portion of the magnet.
偏光子23と検光子25との偏光面を90゜の直交状態に置
いていた場合、磁石の中に挿入される棒状ファラデー素
子の量が大きくなればなる程ファラデー効果による偏光
面の回転角が大きくなり、その結果検光子25を通過さて
受光器27に入射する光の量も多くなる。When the polarization planes of the polarizer 23 and the analyzer 25 are placed in a 90 ° orthogonal state, the rotation amount of the polarization plane due to the Faraday effect increases as the amount of rod-shaped Faraday elements inserted in the magnet increases. As a result, the amount of light that passes through the analyzer 25 and enters the light receiver 27 also increases.
従って、受光器27にて検出される光の量を知ることに
より、筒状磁石28の移動量から、これに連動するアクチ
ュエータの位置を検出することが出来るものである。Therefore, by knowing the amount of light detected by the light receiver 27, it is possible to detect the position of the actuator interlocked with the movement amount of the cylindrical magnet 28.
なお、筒状磁石28として永久磁石の代りに空芯コイル
を用いることができ、この場合、空芯コイルに流す電流
を十分大きくし、常にファラデー光学素子の磁化を飽和
させておくことにより安定した位置の検出が行われる。An air-core coil can be used instead of the permanent magnet as the cylindrical magnet 28, and in this case, the current flowing in the air-core coil is sufficiently large to stabilize the magnetization of the Faraday optical element. The position is detected.
また、周囲の温度モニターし、コイルに流す電流を制
御することにより、温度補償を行うことをもできる。In addition, temperature compensation can be performed by monitoring the ambient temperature and controlling the current flowing through the coil.
本発明によれば、ファラデー光学素子の測定光入射側
および射出側の端面に偏光子および検光子を取り付けて
いるので、悪環境下で使用されても塵埃や結露による悪
影響を受けず、正確な位置検出を行うことができるとと
もに、集光用のレンズや防塵カバー等が不要な小型で低
コストの位置検出装置を提供することが出来る。さら
に、ファラデー光学素子の磁気飽和部分の長さを変化さ
せて位置を検出するので、温度変化による出力の変化を
確実に抑えることが出来る。According to the present invention, the polarizer and the analyzer are attached to the end faces of the Faraday optical element on the measurement light incident side and the emission side. It is possible to provide a small-sized and low-cost position detection device that can perform position detection and does not require a condenser lens or a dust cover. Furthermore, since the position is detected by changing the length of the magnetically saturated portion of the Faraday optical element, it is possible to reliably suppress changes in output due to temperature changes.
また、筒状磁石の中に棒状のファラデー光学素子を挿
入しているので、測定移動方向と直角な方向、即ち半径
方向の変位に対しては測定結果への影響が少ないので、
比較的中空部の寸法公差を大きくとることができるた
め、加工や組立てが容易であり、従来例のような外部反
射ミラーの取付けが不要なので小型で堅牢な装置を得る
ことが出来る。In addition, since the rod-shaped Faraday optical element is inserted in the cylindrical magnet, the measurement result is less affected by the displacement in the direction perpendicular to the measurement movement direction, that is, the radial direction.
Since the dimensional tolerance of the hollow portion can be made relatively large, it is easy to process and assemble, and there is no need to attach an external reflection mirror as in the conventional example, so that a small and robust device can be obtained.
第１図は本発明実施例の概略説明図で、第１図（ａ）
は、その断面図、第１図（ｂ）は第１図（ａ）における
×−×断面図。第２図及び第３図は従来技術の説明であ
る。 21……測定光源 23……偏光子 24……ファラデー光学素子 24a……測定光入射側端部（測定光入射側の端面） 24b……測定光射出側端部（測定光射出側の端面） 25……検光子 27……受光器 28……筒状磁石FIG. 1 is a schematic explanatory view of an embodiment of the present invention, and FIG. 1 (a)
Is a cross-sectional view thereof, and FIG. 1B is a cross-sectional view taken along the line XX in FIG. 2 and 3 are illustrations of the prior art. 21 …… Measuring light source 23 …… Polarizer 24 …… Faraday optical element 24a …… Measuring light incident side end (end of measuring light incident) 24b …… Measuring light emitting end (end of measuring light emitting side) 25 …… Analyzer 27 …… Receiver 28 …… Cylindrical magnet
Claims (4)
該磁石の軸線方向でこれと相対変位する棒状ファラデー
光学素子を挿入した光位置検出装置であって、 前記ファラデー光学素子の測定光入射側端面に偏光子を
取り付けるとともに、 測定光射出端面に検光子を取り付け、 前記筒状磁石と前記ファラデー光学素子の相対変位によ
り前記ファラデー光学素子の磁気飽和する部分の長さを
変化させることで、該変位を検出することを特徴とする
アナログ式ファラデー効果型光位置検出装置。1. A hollow portion of a cylindrical magnet magnetized in the axial direction,
An optical position detecting device in which a rod-shaped Faraday optical element that is displaced relative to the magnet in the axial direction of the magnet is inserted, wherein a polarizer is attached to the end face of the Faraday optical element on the measurement light incident side, and an analyzer is attached to the end face of the measurement light emission. An analog type Faraday effect light characterized by detecting the displacement by changing the length of the magnetically saturated portion of the Faraday optical element by relative displacement of the cylindrical magnet and the Faraday optical element. Position detection device.
る請求項第１記載のアナログ式ファラデー効果型光位置
検出装置。2. The analog type Faraday effect type optical position detecting device according to claim 1, wherein the cylindrical magnet is a permanent magnet.
ことを特徴とする請求項第１記載のアナログ式ファラデ
ー効果型光位置検出装置。3. The analog type Faraday effect type optical position detecting device according to claim 1, wherein the cylindrical magnet is composed of a hollow coil.
測定光射出側の検光子には受光器が、それぞれ光導体に
より接続されていることを特徴とする請求項第１、第
２、第３に記載したいずれかのアナグ式ファラデー効果
型光位置検出装置。4. A light source for measurement is provided on the polarizer on the measurement light incident side,
A light receiver is connected to each of the analyzers on the measurement light emission side by a light conductor, and the anag type Faraday effect type optical position detection device according to any one of claims 1, 2 and 3 is characterized. apparatus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63079958A JP2543566B2 (en) | 1988-03-31 | 1988-03-31 | Analog type Faraday effect type optical position detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63079958A JP2543566B2 (en) | 1988-03-31 | 1988-03-31 | Analog type Faraday effect type optical position detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01250821A JPH01250821A (en) | 1989-10-05 |
| JP2543566B2 true JP2543566B2 (en) | 1996-10-16 |
Family
ID=13704816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63079958A Expired - Lifetime JP2543566B2 (en) | 1988-03-31 | 1988-03-31 | Analog type Faraday effect type optical position detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2543566B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5655811A (en) * | 1979-10-15 | 1981-05-16 | Mitsubishi Electric Corp | Sensor |
| JPS58200166A (en) * | 1982-05-19 | 1983-11-21 | Hitachi Ltd | Measuring system for contactless tachometer |
-
1988
- 1988-03-31 JP JP63079958A patent/JP2543566B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01250821A (en) | 1989-10-05 |
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