JPS61212773A - Photosensor - Google Patents

Abstract

PURPOSE:To achieve a higher sensitivity of a photo sensor, by a method wherein opposed two planes of a medium are tapered at a specified angle and a polarized light from a polarizing means is made incident on the medium to be reflected on the two planes facing each other several times and the polarization component of a specified direction is taken out with a photo detection element on one end side larger in the interval between the two planes of the medium. CONSTITUTION:Opposed reflecting surfaces 7 of a medium 1 comprising an electrooptic material or a magnetooptic material are tapered at a certain angle (2alpha). A light L1 made incident into a horizontal plane 9 at an incident angle theta is converted into linearly polarized or circularly polarized light by a polarization means 8 and reflected on a reflecting surface 7 inclined by an angle alpha of from the horizontal plance 9. Then, as the reflection is repeated on the reflecting surface 7, the incident angle of the light approaches zero gradually and finally reaches zero, where the light returns to the incidence side again and turns to an emission light l2 to obtain a propagation optical path longer in substance in the medium 1. Since the angle of rotation of the polarization surface to the emission of the light from the incidence thereof into the medium 1 is proportional to th propagation optical path length therein 1, the longer the propagation optical path length, the higher the sensitivity of a photosensor.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は電界あるいは磁界を検出する光センサに関する
。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to optical sensors that detect electric or magnetic fields.

従来の技術 近年、光フアイバ技術の発展に伴なって、計測分野にお
いて、透過性や反射性の様々な媒質の物性の変化を光で
検出して、所望の測定項目を測定する。光センサの導入
が活発化している。特に、光ファイバは電気的に絶縁性
、無誘導性を有しているので、同様の性質を持つ光セン
サとの組合せによるセンサシステムで電界、磁界を検出
して電圧、電流を測定すれば、金属線路を用いた測定に
伴われる感電等の危険を冒すことなく高電圧士の計測を
行なうことができる。そこで電力分野において高感度の
電界、磁界検出用光センサの実用化が大きく叫ばれてい
る。BACKGROUND OF THE INVENTION In recent years, with the development of optical fiber technology, in the field of measurement, desired measurement items are measured by detecting changes in the physical properties of various transparent and reflective media using light. Optical sensors are increasingly being introduced. In particular, optical fibers are electrically insulating and non-inductive, so if you use a sensor system in combination with an optical sensor with similar properties to detect electric and magnetic fields and measure voltage and current, High voltage technicians can perform measurements without running the risk of electric shock and the like associated with measurements using metal lines. Therefore, in the power field, there is a great demand for the practical application of highly sensitive optical sensors for detecting electric and magnetic fields.

従来の電界検出用光センサの構成図を第５図に示す。入
射光り、は偏光子２を通って直線偏光に、さらにス波長
板３を通って円偏光に変換され、電気光学定数をもつ媒
質１に入射角θで入射される。A configuration diagram of a conventional optical sensor for detecting an electric field is shown in FIG. The incident light is converted into linearly polarized light through a polarizer 2, and into circularly polarized light through a wavelength plate 3, and is incident on a medium 1 having an electro-optic constant at an incident angle θ.

媒質１の相対する平行な２平面７には全反射膜６が付加
されており、この光は２平６面７の間を多重反射した後
、偏光補償板５、検光子４を通り出射光Ｌ２となる。A total reflection film 6 is added to two opposing parallel planes 7 of the medium 1, and after this light undergoes multiple reflections between the two planes and six planes 7, it passes through a polarization compensator 5 and an analyzer 4 and becomes an output light. It becomes L2.

ところで、このとき媒質１に電界Ｅが加えられていたも
のとすると、電気光学定数を有する媒質１の屈折率楕円
体が変形をひき起こし、媒質１は電界Ｅの大きさに応じ
た複屈折性を有するので、偏光子２およびス波長板３で
円偏光に変換された入射光り、は媒質１を通過すること
により楕円偏光となる。従って、偏光補償板５および検
光子４を通過した出射光Ｌ２のエネルギーは電界Ｅの大
きさに応じたものとなり、このエネルギーを測定するこ
とにより電界Ｅの大きさを求めることができる。By the way, if we assume that an electric field E is applied to the medium 1 at this time, the refractive index ellipsoid of the medium 1 having an electro-optic constant causes deformation, and the medium 1 exhibits birefringence according to the magnitude of the electric field E. Therefore, the incident light converted into circularly polarized light by the polarizer 2 and wavelength plate 3 becomes elliptically polarized light by passing through the medium 1. Therefore, the energy of the emitted light L2 that has passed through the polarization compensator 5 and the analyzer 4 corresponds to the magnitude of the electric field E, and by measuring this energy, the magnitude of the electric field E can be determined.

一方、磁界検出用光センサは第５図の電界検出用光セン
サの２波長板３を除去し、さらに媒質１の代わりに磁気
光学定数を有する媒質を設けたような構成をしている。On the other hand, the optical sensor for detecting a magnetic field has a structure in which the two-wavelength plate 3 of the optical sensor for detecting an electric field shown in FIG. 5 is removed, and a medium having a magneto-optic constant is provided in place of the medium 1.

そして、偏光子２により直線偏光に変換された入射光Ｌ
１が媒質を通過する。Then, the incident light L converted into linearly polarized light by the polarizer 2
1 passes through the medium.

このとき磁界Ｈが存在するとファラデー効果が生じて直
線偏光の偏光面が磁界Ｈの大きさに応じて回転し、偏光
補償板５、検光子４に入射する。従って、磁界Ｈの大き
さが０であって偏光面が回転しないときのこの偏光面と
直交するように予め検光子４を設置しておけば、出射光
Ｌ２エネルギーは磁界Ｈの大きさに応じたものとなる。At this time, if the magnetic field H is present, a Faraday effect occurs, and the polarization plane of the linearly polarized light rotates according to the magnitude of the magnetic field H, and the linearly polarized light is incident on the polarization compensator 5 and the analyzer 4. Therefore, if the analyzer 4 is installed in advance so as to be orthogonal to the plane of polarization when the magnitude of the magnetic field H is 0 and the plane of polarization does not rotate, the energy of the emitted light L2 will depend on the magnitude of the magnetic field H. It becomes something.

すなわち、出射光Ｌ２のエネルギーを検出することによ
り磁界Ｈの大きさを求めることができる。That is, the magnitude of the magnetic field H can be determined by detecting the energy of the emitted light L2.

発明が解決しようとする問題点 媒質１に入射してから出射するまでの偏光面の回転角は
媒質１中の伝搬光路長りに比例するので、伝搬光路長し
が大きいほど光センサの感度が高くなる。例えば、入射
光が媒質１を１回通過させるだけの光センサに比べて、
反射面で１回反射させ、媒質１を２回通過させる光セン
サは２倍の伝搬光路長しすなわち２倍の感度を持ってお
り、同様にしてｎ回反射させるとｎ＋１倍の感度を有す
る。Problems to be Solved by the Invention Since the rotation angle of the plane of polarization from the time it enters the medium 1 to the time it exits is proportional to the length of the optical propagation path in the medium 1, the greater the length of the optical propagation path, the greater the sensitivity of the optical sensor. It gets expensive. For example, compared to an optical sensor in which the incident light passes through the medium 1 only once,
An optical sensor that reflects once on a reflective surface and passes through medium 1 twice has twice the propagation path length, that is, has twice the sensitivity, and similarly, when reflected n times, it has n+1 times the sensitivity.

第５図に示されるような多重反射型光センサでは入射角
θによって伝搬光路長しが異なるが実際には入射角θは
小さい値であるので、やはり感度ｍは反射回数ｎによっ
て決定されると言える。第５図から反射回数ｎは、 β ｎ＝　　　　　　　−１・・・・（１）Ｗｌ　ｔａｎθ ただし、ｌ：媒質１の実行長 Ｗ：媒質１の厚さ θ：入射角 であり、感度ｍは次式で表わされる。In a multiple reflection type optical sensor as shown in Fig. 5, the propagation optical path length differs depending on the incident angle θ, but in reality the incident angle θ is a small value, so the sensitivity m is determined by the number of reflections n. I can say it. From Fig. 5, the number of reflections n is β n= -1 (1) Wl tanθ where l: effective length of medium 1 W: thickness of medium 1 θ: angle of incidence, and sensitivity m is as follows. It is expressed by the formula.

ｍ＝　（ｎ＋　１）ＸＥＸＰ ＝　Ｃ］　ＸＥＸＰ　　・・・・（２）Ｗ−ｔａｎθ 〔〕ニガウス記号 Ｅ　：電界の大きさ Ｐ　：媒質１の電気光学定数 例えば、Ｉｔ　＝３０ｍｍ、　Ｗ　＝　５　ｍｍ、θ＝
１０°とすると、感度ｍ＝１１・Ｅ−Ｐとなる。ここで
、電気光学定数Ｐは媒質１の結晶に固有の値であるので
、感度ｍは媒質１を構成する結晶の長さｌに比例し、結
晶の厚みＷおよび入射角θの正接ｔａｎθに反比例する
。従って、感度ｍを高めようとするには、結晶長さｌを
大きくする、結晶の厚さＷを小さくする、あるいは正接
ｔａｎθを小さくすればよい。m= (n+ 1)XEXP = C] θ=
When the angle is 10°, the sensitivity m=11·E−P. Here, since the electro-optical constant P is a value specific to the crystal of medium 1, the sensitivity m is proportional to the length l of the crystal constituting medium 1, and inversely proportional to the thickness W of the crystal and the tangent tanθ of the incident angle θ. do. Therefore, in order to increase the sensitivity m, the crystal length l may be increased, the crystal thickness W may be reduced, or the tangent tan θ may be reduced.

ところで、正接ｔａｎθがある値以下になる、すなわち
入射角θがある値以下であると、入射点Ｐ。Incidentally, when the tangent tan θ is below a certain value, that is, when the incident angle θ is below a certain value, the incident point P.

と入射側の反射面７上の最初の反射点Ｐ１　との間隔が
光束の直径以下になって効率的なエネルギー入射が行な
われなくなるので、正接ｔａｎθはある一定値以上にし
ておく必要がある。そこで、感度ｍを高めるためには、
結晶の長さ！を厚さＷに比べてできるだけ大きく設定し
なければならない。Since the distance between the light beam and the first reflection point P1 on the reflection surface 7 on the incident side becomes less than the diameter of the luminous flux, efficient energy injection is no longer performed, so the tangent tan θ must be set to a certain value or more. Therefore, in order to increase the sensitivity m,
Crystal length! must be set as large as possible compared to the thickness W.

なお、磁界検出用光センサについても同様のことが言え
る。Note that the same can be said of the optical sensor for detecting a magnetic field.

このように従来は高感度の多重反射型光センサを実現し
ようとすると大型化してしまうという問題点を有してい
た。As described above, conventionally, when attempting to realize a highly sensitive multiple reflection type optical sensor, the sensor becomes large in size.

本発明の目的は小型でかつ高感度の光センサを提供する
ことにある。An object of the present invention is to provide a compact and highly sensitive optical sensor.

問題点を解決するための手段 本発明の光センサは第１図に示されるように、媒質１の
相対する反射面７が平行ではなく、ある角度（２α）を
なして設けられてテーパ構造となり、入射角θで入射し
た光Ｌ１が反射面７での反射を繰返すうちに次第に入射
角が０に近くなり、ついには０となって再び入射側へ戻
り出射光Ｌ２となることによって媒質１中において実質
的に長い光路長を得るものである。Means for Solving the Problems As shown in FIG. 1, the optical sensor of the present invention has a tapered structure in which the opposing reflecting surfaces 7 of the medium 1 are not parallel but are arranged at a certain angle (2α). As the light L1 enters at an incident angle θ and is repeatedly reflected on the reflecting surface 7, the incident angle gradually approaches 0, and finally reaches 0 and returns to the incident side again to become the output light L2, which causes light to enter the medium 1. In this case, a substantially long optical path length is obtained.

本発明の好ましい態様においては、第２図に示されるよ
うに、直線偏光または円偏光を発生させる偏光手段８お
よび検光子４と媒質ｌとの間に媒質１よりも屈折率の高
い物質１１が挿入されている。In a preferred embodiment of the present invention, as shown in FIG. 2, a substance 11 having a higher refractive index than the medium 1 is provided between the polarizing means 8 for generating linearly polarized light or circularly polarized light, the analyzer 4, and the medium 1. It has been inserted.

詐月 まず、本発明による光センサの動作原理を説明する。第
３図は第１図の点線の部分Ａの拡大図である。この図に
おいて、水平面９に対して入射角θで入射した光り、は
、偏光手段８で直線偏光あるいは円偏光に変換された後
、水平面９とαの角度をなす傾いた反射面７で反射され
る。その時、反射光Ｌ３の水平面９に対する反射角はθ
−２αとなる。次に反射光Ｌ３は同様に水平面９とαの
角度をなす相対する反射面７に水平面９に対する入射角
θ−２αで入射し、今度は水平面９に対する反射角θ−
４αで反射される。First, the operating principle of the optical sensor according to the present invention will be explained. FIG. 3 is an enlarged view of the dotted line section A in FIG. In this figure, light incident on a horizontal surface 9 at an incident angle θ is converted into linearly polarized light or circularly polarized light by a polarizing means 8, and then reflected by an inclined reflecting surface 7 forming an angle α with the horizontal surface 9. Ru. At that time, the reflection angle of the reflected light L3 with respect to the horizontal plane 9 is θ
-2α. Next, the reflected light L3 similarly enters the opposing reflecting surface 7 that forms an angle of α with the horizontal surface 9 at an incident angle θ−2α with respect to the horizontal surface 9, and this time, the reflected light L3 enters at an incident angle θ−2α with respect to the horizontal surface 9.
It is reflected by 4α.

このようにして相対する反射面７で順次ｎ回反射される
と、水平面９に対する入射角はθ−２ｎαとなる。ここ
で、予め角θ及びαを適当な値に設定しておくと、ある
反射回数ｎで入射角は、θ−２ｎα＝０　　　　　　　
・・・・（３）となり、入射光は第１図に示すように、
これまでたどってきた光路と上下対称の光路を通り、再
び反射面７でｎ回反射した後、偏光補償板５、検光子４
を通って出射光Ｌ２となる。すなわち、（３）式よりｎ
＝θ／２αとなるので、往復の反射回数Ｎは、 Ｎ＝２ｎ＝２　（θ／　２　ｃｘ　）　　　・・・・（
４）となる。When the light is reflected n times by the opposing reflecting surfaces 7 in this manner, the angle of incidence with respect to the horizontal surface 9 becomes θ-2nα. Here, if the angles θ and α are set to appropriate values in advance, the incident angle will be θ−2nα=0 at a certain number of reflections n.
...(3), and the incident light is as shown in Figure 1,
After passing through an optical path that is vertically symmetrical to the optical path that has been traced so far and being reflected n times at the reflecting surface 7, the polarization compensator 5 and the analyzer 4
It becomes the emitted light L2. That is, from equation (3), n
= θ/2α, so the number of round-trip reflections N is: N=2n=2 (θ/2 cx ) ・・・・・・(
4).

この光センサの感度はやはり反射回数Ｎにより決まり、
電界検出用光センサを例にとると、（２）式％式％ となる。なお、この場合媒質１の光の入射点から入射角
が０となる折返し点までの距離ｌは次式で示されるので
、媒質１はこの距離１以上の長さを持つ必要がある。The sensitivity of this optical sensor is determined by the number of reflections N,
Taking an optical sensor for detecting an electric field as an example, the formula (2) is as follows. In this case, the distance l from the light incidence point of the medium 1 to the turning point where the incident angle becomes 0 is expressed by the following equation, so the medium 1 must have a length equal to or greater than this distance 1.

２　　　　　　　ｔａ口α　　　　　　　　　　　　　
　・・・・（６）ただし、Ｗは媒質１の最大厚みである
。2 ta mouth α
...(6) However, W is the maximum thickness of the medium 1.

（５）式かられかるように感度ｍは入射角θおよび反射
面７の水平面９に対する角度αの各位によって決定され
る。例えば入射角θ＝１０°　とすると、α＝１°の時
１．：ｍ＝１１ＥＸＰ、α＝０．５の時ｍ＝２１ＸＥＸ
Ｐ、ａ＝　０゜１°の時、ｍ＝　ｌ０ＩＸＥＸＰとなる
。As can be seen from equation (5), the sensitivity m is determined by the incident angle θ and the angle α of the reflecting surface 7 with respect to the horizontal plane 9. For example, if the incident angle θ=10°, when α=1°, 1. : m=11EXP, m=21XEX when α=0.5
When P, a= 0°1°, m= l0IXEXP.

（３）式より理論的には角αが小さくなればなる程、感
度ｍが高くなるが、角αが小さくなると伝搬光路が長く
なり挿入損失が増加する。感度ｍの増加分が挿入損失の
増加分に等しくなるとシステム的にみて高感度化の効果
は零となってしまう。すなわち、この時が角αの下限値
となる。以下、角αの下限値について説明する。According to equation (3), theoretically, the smaller the angle α, the higher the sensitivity m becomes. However, as the angle α becomes smaller, the propagation optical path becomes longer and the insertion loss increases. When the increase in sensitivity m becomes equal to the increase in insertion loss, the effect of increasing sensitivity becomes zero from a system perspective. That is, this time becomes the lower limit value of the angle α. The lower limit value of the angle α will be explained below.

本発明の光センサにおける伝１般光路長しは次のように
表わされる。The general optical path length of the optical sensor of the present invention is expressed as follows.

Ｗ：媒質の厚み Ｎ：反射回数 θ：入射角 ところで、全反射膜６は一般に多層膜で構成されるので
、入射角θは１５°以下でなければ反射特性が劣化して
しまうことは周知である。そこで、反射回数Ｎを１００
程度以上の大きな値に設定すると（７）式は次のように
近似される。W: Thickness of the medium N: Number of reflections θ: Incident angle By the way, since the total reflection film 6 is generally composed of a multilayer film, it is well known that the reflection characteristics will deteriorate unless the incident angle θ is 15° or less. be. Therefore, the number of reflections N is set to 100.
If the value is set to a value larger than 100, the equation (7) can be approximated as follows.

Ｌ＝ＮＷ　　　　　　　　　　・・・・（８）また、反
射面７上の各反射点において各光束が重ならず、効率的
に光が媒質１の内部を伝搬するために（を媒質の厚さを
Ｗ１人射角をθ、光束の径をａとして各反射点の間隔Ｗ
　ｔａｎθが光束の径の２倍以上であることが必要であ
る。すなわち、Ｗ　ｔａｎθ≧２ａ　　　　　　　”（
９）となる。L=NW (8) Also, in order for the light beams to efficiently propagate inside the medium 1 without overlapping each other at each reflection point on the reflection surface 7, the thickness of the medium is set to W1. The interval W between each reflection point, where the angle of human incidence is θ and the diameter of the luminous flux is a
It is necessary that tan θ is twice or more the diameter of the luminous flux. That is, W tanθ≧2a ”(
9).

媒質１内を伝搬する光束の径ａは励振用ファイバのコア
径が５０μｍということを考えると５０μｍ以下には絞
れず、かつ入射角θの最大値は１５°であるので（９）
式より次の関係式が成り立つことがわかる。Considering that the core diameter of the excitation fiber is 50 μm, the diameter a of the light beam propagating in the medium 1 cannot be narrowed down to less than 50 μm, and the maximum value of the incident angle θ is 15° (9)
From the equation, it can be seen that the following relational expression holds true.

Ｗ２Ｏ，３７３（ｍｍ）　　　　　　　　　””１口こ
のα１式を（８）式に代入すると、 し≧０．３７３・Ｎ　（ｍｍ）　　　　　・・・（１１
）となる。W2O, 373 (mm) ``'' 1 mouth Substituting this α1 formula into formula (8), then ≧0.373・N (mm) ・・・(11
).

第４図に媒質的伝搬光束の径ａを１００μｍとした時の
挿入損失を示す。（１１）式を用いて第４図の伝搬光路
長りを反射回数Ｎに変換し、また前述したように、反射
回数Ｎの多重反射型光センサの感度反射回数０の場合に
比べてＮ＋１倍となるので、この感度の倍数Ｎ＋１をデ
シベル表示することにより、伝導光路長しがＬＬｌｍｍ
のとき感度が２４．７ｄＢすなわち３００倍となり、挿
入損失も２４．７ｄＢとなって、３００倍の感度が高感
度化の限界となることがわかる。FIG. 4 shows the insertion loss when the diameter a of the medium-propagating light beam is 100 μm. Using equation (11), the propagation optical path length in Fig. 4 is converted into the number of reflections N, and as mentioned above, the sensitivity of the multiple reflection type optical sensor with the number of reflections N is N+1 times as compared to the case where the number of reflections is 0. Therefore, by expressing the multiple N+1 of this sensitivity in decibels, the conduction optical path length is LLlmm.
When the sensitivity is 24.7 dB, that is, 300 times higher, the insertion loss is also 24.7 dB, and it can be seen that the sensitivity of 300 times is the limit of high sensitivity.

この時（４）式より、 ２９９＝θ／α　　　　　　・・・・（１２）となり、
さらに入射角θの最大値１５°をこの（１２）式に代入
すると角αの下限値は０．０５°となる。At this time, from equation (4), 299=θ/α (12),
Further, when the maximum value of the incident angle θ, 15°, is substituted into this equation (12), the lower limit value of the angle α becomes 0.05°.

すなわち、反射面７のなす角２αは０．１°以上である
ことが必要である。That is, the angle 2α formed by the reflective surface 7 needs to be 0.1° or more.

また、第１図のような光センサを実際に製作する場合、
入射角が小さいので第３図の拡大図において、電気光学
定数あるいは磁気光学定数を有する媒質１からの出射光
Ｌ２と反射面７による反射光Ｌ３との間隔Ｓが小さく、
これらの光Ｌ２とＬ３との分離が容易ではない。例えば
、厚さＷが５ｍｍ。Also, when actually manufacturing an optical sensor like the one shown in Figure 1,
Since the incident angle is small, in the enlarged view of FIG. 3, the distance S between the emitted light L2 from the medium 1 having an electro-optic constant or magneto-optic constant and the reflected light L3 by the reflecting surface 7 is small;
It is not easy to separate these lights L2 and L3. For example, the thickness W is 5 mm.

入射角θが１０°の場合には出射光Ｌ２と反射光Ｌ３と
の間隔Ｓは１．７６ｍｍとなり、光束の径を１ｍｍと仮
定すると、０．７６ａｕｎシか分離のための余裕がなく
、分離が困難となってしまう。When the incident angle θ is 10°, the distance S between the emitted light L2 and the reflected light L3 is 1.76 mm, and assuming that the diameter of the light beam is 1 mm, there is no margin for separation of 0.76 aun. becomes difficult.

そこで、第２図のように、電気光学定数もしくは磁気光
学定数を有する媒質１と偏光手段８及び偏光補償板５と
の間に媒質１よりも高い屈折率を有する媒質１１を挿入
する。すると、入射光Ｌ１が媒質１１から媒質１へ入射
するとき、および出射光Ｌ２が媒質１から媒質１１へ入
射するときにそれぞれ屈折するので、水平面９に対する
入射光り、の入射角θおよび出射光Ｌ２の取出し角θを
ともに大きく設定することができる。従って、出射光Ｌ
２を反射面７での反射光Ｌ３から分離させ、あるいは入
射光Ｌ１　から分離させて取出すことが容易となる。Therefore, as shown in FIG. 2, a medium 11 having a higher refractive index than the medium 1 is inserted between the medium 1 having an electro-optic constant or a magneto-optic constant and the polarizing means 8 and the polarization compensating plate 5. Then, since the incident light L1 is refracted when it enters the medium 1 from the medium 11, and the outgoing light L2 is refracted when it enters the medium 11 from the medium 1, the incident angle θ of the incident light with respect to the horizontal plane 9 and the outgoing light L2 Both of the take-out angles θ can be set large. Therefore, the output light L
2 from the reflected light L3 on the reflecting surface 7 or from the incident light L1.

おな、媒質１１の屈折率は、媒質１に光が入射する時に
全反射を起こさない程度に低く抑える必要がある。また
、媒質１と媒質１１との境界面は光の反射を抑えるため
に反射防止膜がコーティングされていることが望ましい
。Note that the refractive index of the medium 11 needs to be kept low enough to prevent total reflection when light is incident on the medium 1. Further, it is desirable that the interface between the medium 1 and the medium 11 be coated with an antireflection film to suppress reflection of light.

なお、上記した作用は、媒質１の互いに対向する反射面
７が水平面９に対して互いに対称に傾斜している場合に
ついて説明した。しかし、本発明は、対向する一対の反
射面７の一方のみが水平面９に対して傾斜し、他方の反
射面が水平面９に対して平行であってもよい。その場合
も、それら一対の反射面のなす角度を２αとするならば
、傾斜した反射面での反射ごとに光の水平面９に対する
角度が４αずつ減少することだけが異なり、上記した関
係が同様に成立し、また、同様な効果を得ることができ
る。Note that the above-mentioned effects have been described in the case where the mutually opposing reflecting surfaces 7 of the medium 1 are inclined symmetrically with respect to the horizontal plane 9. However, in the present invention, only one of the pair of opposing reflecting surfaces 7 may be inclined with respect to the horizontal surface 9, and the other reflecting surface may be parallel to the horizontal surface 9. In that case, if the angle formed by the pair of reflecting surfaces is 2α, the only difference is that the angle of the light with respect to the horizontal plane 9 decreases by 4α for each reflection on the inclined reflecting surface, and the above relationship is the same. This is true, and similar effects can be obtained.

実施例 以下、本発明の実施例について説明する。Example Examples of the present invention will be described below.

実施例１ 第１の実施例は第１図において、まず媒質１として厚さ
０．５ｍｍ、長さ４．３ｍｍの８！＋ｚＳ１０□ｏ結晶
を用い、表面をテーパ状に研磨して相対する表面のなす
角２αを０．１°とした。次に、これらの表面上にＴｉ
Ｏ２、Ｓｉｎ、の多層膜による全反射膜６を形成する。Example 1 In the first example, in FIG. 1, the medium 1 is 8! having a thickness of 0.5 mm and a length of 4.3 mm. A +zS10□o crystal was used, and the surfaces were polished into a tapered shape so that the angle 2α between the opposing surfaces was 0.1°. Next, Ti is deposited on these surfaces.
A total reflection film 6 made of a multilayer film of O2 and Sin is formed.

さらに、媒質１の相対する表面の一部を水平面９に対し
て角１０°になるようにそれぞれ研磨し、一方に偏光手
段８としてＸ波長板および偏光子を設け、他方に偏光補
償板５および検光子４を設けて電界検出用光センサを構
成した。Further, parts of the opposing surfaces of the medium 1 are polished so that they form an angle of 10° with respect to the horizontal plane 9, and an X wavelength plate and a polarizer are provided as polarizing means 8 on one side, and a polarization compensating plate 5 and a polarizer on the other side. An analyzer 4 was provided to constitute an optical sensor for detecting an electric field.

光を入射角１０’で入射させて電界の測定を行なったと
ころ、第５図に示した従来の多重反射型光センサに比べ
て１０倍以上の感度が得られた。When the electric field was measured with light incident at an incident angle of 10', a sensitivity more than 10 times that of the conventional multiple reflection type optical sensor shown in FIG. 5 was obtained.

実施例２ 第２の実施例は第２図において、媒質１として第１の実
施例のＢ１１゜５ｉＯ２ｏ結晶と同一のものを用い、や
はりテーパ状の表面のなす角２αを０．１゜として、こ
れらの表面上にＴｉ１ｔ、ＳｉＯ□の多層膜による全反
射膜６を形成した。次に、媒質１１としてＧａＰを用い
て媒質１の厚さの大きい方の一端面に接するように設置
し、さらに第１の実施例とどうように偏光手段８として
Ｘ波長板、偏光子を設けるとともに偏光補償板５、検光
子４を設けて電界検出用光センサとした。Example 2 In the second example, in FIG. 2, the same B11°5iO2o crystal as the first example was used as the medium 1, and the angle 2α formed by the tapered surface was 0.1°. A total reflection film 6 made of a multilayer film of Ti1t and SiO□ was formed on these surfaces. Next, GaP is used as the medium 11 and installed so as to be in contact with one thick end surface of the medium 1, and further an X wavelength plate and a polarizer are provided as the polarizing means 8 in the same manner as in the first embodiment. A polarization compensation plate 5 and an analyzer 4 were also provided to form an optical sensor for detecting an electric field.

媒質１　（Ｂｉ、２Ｓｉ　Ｏ□。）および（ＧａＰ）の
屈折率はそれぞれ２．４５．３．３１であり、水平面９
に対して媒質１１への入射角を４７°としたところ媒質
１への入射角は９°となり、電界の測定において第１の
実施例と同様の感度が得られた。The refractive index of medium 1 (Bi, 2SiO□.) and (GaP) is 2.45.3.31, respectively, and the horizontal plane 9
On the other hand, when the angle of incidence on the medium 11 was set to 47°, the angle of incidence on the medium 1 was 9°, and the same sensitivity as in the first example was obtained in the measurement of the electric field.

なお、上記実施例１．２では電気光学定数を有する媒質
１としてＢｉ＋２Ｓ！０２ｏを用いたが、ＺｎＳ。In Example 1.2, the medium 1 having an electro-optic constant is Bi+2S! 02o was used, but ZnS.

Ｚｎ５ｅＳＬｉＮｂＯａ、Ｂｔ４（ＧｅＯ４）＋、Ｂｊ
４（ＳＬＯｎ）ｉ、Ｂｉ＋ｚＧｅＯｚｏを用いることも
できる。Zn5eSLiNbOa, Bt4(GeO4)+, Bj
4(SLOn)i, Bi+zGeOzo can also be used.

また、磁界検出用光センサを構成するときには媒質１と
して磁気光学定数を有するＦＲ−５、ＺｎＳ。Moreover, when configuring an optical sensor for detecting a magnetic field, FR-5 or ZnS having a magneto-optical constant is used as the medium 1.

Ｂｉ＋２ＧｅＯｚｏ等を用い、さらに偏光手段８として
は偏光子のみの使用で足りる。It is sufficient to use Bi+2GeOzo or the like, and use only a polarizer as the polarizing means 8.

さらに、上記実施例１．２では全反射膜６としてＴｌＯ
２、Ｓｉｎ、による多層膜を用いたが、他の誘電体材料
による膜でもよい。ただし、一般に反射膜として用いら
れる金、Ａ１などはＰ偏光およびＳ偏光に対する反射率
が異なるので本発明の光センサに用いることは好ましく
ない。Furthermore, in the above embodiment 1.2, the total reflection film 6 is TlO.
Although a multilayer film made of 2.Sin was used, a film made of other dielectric materials may be used. However, gold, A1, and the like, which are generally used as reflective films, have different reflectances for P-polarized light and S-polarized light, so it is not preferable to use them in the optical sensor of the present invention.

発明の詳細 な説明したように本発明によれば、小型でありながら非
常に高感度の光センサを提供することができる。従って
、本発明の光センサを用いることによって、高電圧下に
おいても安全にかつ高精度の電圧、電流測定を行なうこ
とが可能となるので、本発明は電力分野等において有用
なものである。DETAILED DESCRIPTION OF THE INVENTION According to the present invention as described above, it is possible to provide an optical sensor that is small but has very high sensitivity. Therefore, by using the optical sensor of the present invention, it is possible to safely and accurately measure voltage and current even under high voltage, so the present invention is useful in the electric power field and the like.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例にかかる光センサの構成図、
第２図は他の実施例の構成図、第３図は第１図の実施例
の部分拡大図、第４図は伝搬光路長に対する挿入損失を
示すグラフ、第５図は従来の光センサの構成図である。 （主な参照番号） Ｌ、　　・・入射光、　Ｌ２　・・出射光、１・・電気
光学定数もしくは磁気光学定数を有する媒質、 ２・・偏光子、　　３・・Ａ波長板、 ４・・検光子、　　５・・偏光補償板、６・・全反射膜
、　７・・反射面、 ８・・偏光手段、　９・・水平面、 １１・・媒質FIG. 1 is a configuration diagram of an optical sensor according to an embodiment of the present invention,
Fig. 2 is a block diagram of another embodiment, Fig. 3 is a partially enlarged view of the embodiment of Fig. 1, Fig. 4 is a graph showing insertion loss versus propagation optical path length, and Fig. 5 is a diagram of a conventional optical sensor. FIG. (Main reference numbers) L,...Incoming light, L2...Outgoing light, 1...Medium having an electro-optic constant or magneto-optic constant, 2...Polarizer, 3...A wavelength plate, 4...Detection Photon, 5. Polarization compensation plate, 6. Total reflection film, 7. Reflection surface, 8. Polarizing means, 9. Horizontal surface, 11. Medium

Claims (8)

【特許請求の範囲】[Claims] （１）電気光学材料あるいは磁気光学材料からなる媒質
と、前記媒質に偏光を入力させる偏光手段と、前記媒質
からの出射光を受ける検光子とを備え、前記偏光手段か
らの偏光が前記媒質に入射し、前記媒質の相対する２平
面で複数回反射された後、前記検光子に入射して所定の
方向の偏光成分が取り出される光センサにおいて、 前記媒質の前記２平面が所定の角度をなしてテーパ状に
形成されており、前記偏光手段と前記検光子は、前記２
平面間の間隔が広い前記媒質の一方の端部側に位置して
いることを特徴とする光センサ。(1) A medium made of an electro-optic material or a magneto-optic material, a polarizing means for inputting polarized light into the medium, and an analyzer for receiving light emitted from the medium, and the polarized light from the polarizing means is transmitted to the medium. In the optical sensor, the light enters the analyzer and after being reflected multiple times on two opposing planes of the medium, the polarized light components in a predetermined direction are extracted, the two planes of the medium forming a predetermined angle. The polarizing means and the analyzer are formed in a tapered shape.
An optical sensor characterized in that the optical sensor is located on one end side of the medium where the distance between the planes is wide. （２）前記所定の角度が０．１°以上である特許請求の
範囲第１項記載の光センサ。(2) The optical sensor according to claim 1, wherein the predetermined angle is 0.1° or more. （３）前記偏光手段は円偏光を出射し、前記媒質は電気
光学材料からなる特許請求の範囲第１項または第２項記
載の光センサ。(3) The optical sensor according to claim 1 or 2, wherein the polarizing means emits circularly polarized light, and the medium is made of an electro-optic material. （４）前記偏光手段は直線偏光を出射し、前記媒質は磁
気光学材料からなる特許請求の範囲第１項または第２項
記載の光センサ。(4) The optical sensor according to claim 1 or 2, wherein the polarizing means emits linearly polarized light, and the medium is made of a magneto-optical material. （５）電気光学材料あるいは磁気光学材料からなる第１
の媒質と、前記第１の媒質に偏光を入力させる偏光手段
と、前記第１の媒質からの出射光を受ける検光子とを備
え、前記偏光手段からの偏光が前記第１の媒質に入射し
、前記第１の媒質の相対する２平面で複数回反射された
後、前記検光子に入射して所定の方向の偏光成分が取り
出される光センサにおいて、 前記第１の媒質の前記２平面が所定の角度をなしてテー
パ状に形成されており、前記偏光手段と前記検光子は、
前記２平面間の間隔が広い前記第１の媒質の一方の端部
側に位置しており、 前記偏光手段および前記検光子と前記第１の媒質との間
に挿入され、前記第１の媒質の屈折率より大きい屈折率
の第２の媒質を有していることを特徴とする光センサ。(5) The first layer is made of an electro-optic material or a magneto-optic material.
a medium, a polarizing means for inputting polarized light into the first medium, and an analyzer for receiving light emitted from the first medium, the polarized light from the polarizing means is input to the first medium. , an optical sensor in which a polarized light component in a predetermined direction is extracted by entering the analyzer after being reflected multiple times on two opposing planes of the first medium, wherein the two planes of the first medium are in a predetermined direction. The polarizing means and the analyzer are formed in a tapered shape at an angle of
located on one end side of the first medium where the distance between the two planes is wide, and inserted between the polarizing means and the analyzer and the first medium; An optical sensor comprising a second medium having a refractive index greater than the refractive index of the second medium. （６）前記所定の角度が０．１°以上である特許請求の
範囲第５項記載の光センサ。(6) The optical sensor according to claim 5, wherein the predetermined angle is 0.1° or more. （７）前記偏光手段は円偏光を出射し、前記第１の媒質
は電気光学材料からなる特許請求の範囲第５項または第
６項記載の光センサ。(7) The optical sensor according to claim 5 or 6, wherein the polarizing means emits circularly polarized light, and the first medium is made of an electro-optic material. （８）前記偏光手段は直線偏光を出射し、前記第１の媒
質は磁気光学材料からなる特許請求の範囲第５項または
第６項記載の光センサ。(8) The optical sensor according to claim 5 or 6, wherein the polarizing means emits linearly polarized light, and the first medium is made of a magneto-optical material.