JPH01127984A - Magnetic field sensor - Google Patents
Magnetic field sensorInfo
- Publication number
- JPH01127984A JPH01127984A JP28586187A JP28586187A JPH01127984A JP H01127984 A JPH01127984 A JP H01127984A JP 28586187 A JP28586187 A JP 28586187A JP 28586187 A JP28586187 A JP 28586187A JP H01127984 A JPH01127984 A JP H01127984A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- light
- polarizer
- faraday
- field sensor
- 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.)
- Pending
Links
- 239000011701 zinc Substances 0.000 claims abstract description 10
- 229910052714 tellurium Inorganic materials 0.000 claims abstract description 8
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910004611 CdZnTe Inorganic materials 0.000 claims abstract description 6
- 230000003287 optical effect Effects 0.000 claims description 13
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 7
- 229910052725 zinc Inorganic materials 0.000 claims description 7
- 229910052793 cadmium Inorganic materials 0.000 claims description 6
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 6
- 238000005259 measurement Methods 0.000 abstract description 9
- 230000010287 polarization Effects 0.000 abstract description 7
- 239000013307 optical fiber Substances 0.000 abstract description 5
- 229910004613 CdTe Inorganic materials 0.000 abstract description 2
- 239000013078 crystal Substances 0.000 abstract description 2
- CEKJAYFBQARQNG-UHFFFAOYSA-N cadmium zinc Chemical compound [Zn].[Cd] CEKJAYFBQARQNG-UHFFFAOYSA-N 0.000 abstract 1
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000035945 sensitivity Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910007709 ZnTe Inorganic materials 0.000 description 1
- QWUZMTJBRUASOW-UHFFFAOYSA-N cadmium tellanylidenezinc Chemical compound [Zn].[Cd].[Te] QWUZMTJBRUASOW-UHFFFAOYSA-N 0.000 description 1
- RPPBZEBXAAZZJH-UHFFFAOYSA-N cadmium telluride Chemical compound [Te]=[Cd] RPPBZEBXAAZZJH-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
Abstract
Description
【発明の詳細な説明】
（イ）発明の属する技術分野
本発明は磁界センサに関し、より詳細にはファラデー効
果を利用した磁界センサに関する０（ロ）従来技術とそ
の問題点
鉛ガラス等の光の透過性の良い磁気光学材料に外ｊｉｔ
ｓから磁界を加え、磁界と同じ方向に光を透過させると
ファラデー効果により磁気光学材料を通−過中に光の偏
波面が回転する現象が知られている０偏波面の回転角θ
（０）は下式により与えられる０θ＝ Ｖ ｅ Ｈｌ
・・・・・・ （１）ここで、ｖｅ：ベルデ定数
（０１０ｅ°ｍ）Ｈ：磁界の強さ（Ｏｅ）
ｌ ：ファラデー回転素子の長さ（闘）この磁気旋光現
象を利用して磁界の測定を行うことができる。Detailed Description of the Invention (a) Technical field to which the invention pertains The present invention relates to a magnetic field sensor, and more particularly relates to a magnetic field sensor using the Faraday effect. (b) Prior art and its problems The outer jit is made of magneto-optical material with good transparency.
It is known that when a magnetic field is applied from s and light is transmitted in the same direction as the magnetic field, the polarization plane of the light rotates while passing through the magneto-optical material due to the Faraday effect.The rotation angle θ of the zero polarization plane
(0) is given by the following formula 0θ= V e Hl
...... (1) Here, ve: Verdet constant (010e°m) H: Magnetic field strength (Oe) l: Length of Faraday rotation element (T) Using this magnetic optical rotation phenomenon, the magnetic field is can be measured.
第３図はファラデー効果を利用した磁界センサの一例を
示している。同図によると、光源からの出射光は偏光子
４で無偏光の光から直線偏光にされた後、ファラデー回
転素子６０に入射する。入射した直線偏光は、ファラデ
ー回転素子６０を透過する間に磁界７の影響により偏波
面が角度θだけ回転された後、検光子８で光強度に変換
され、光検出器（ホトダイオード等）により検出される
。FIG. 3 shows an example of a magnetic field sensor using the Faraday effect. According to the figure, the light emitted from the light source is converted from non-polarized light to linearly polarized light by a polarizer 4, and then enters a Faraday rotator 60. The incident linearly polarized light has its plane of polarization rotated by an angle θ due to the influence of the magnetic field 7 while passing through the Faraday rotation element 60, and is then converted into light intensity by the analyzer 8 and detected by a photodetector (photodiode, etc.). be done.
ここで、偏光子４と検光子８との間には光軸に関して４
５°ずれていて、回転角θに比例する光強度変化を受け
た光が検光子８から出射するよ５＞てしている。Here, between the polarizer 4 and the analyzer 8, there are 4
The light that is shifted by 5 degrees and undergoes a light intensity change proportional to the rotation angle θ is emitted from the analyzer 8.
上記磁界センサでは、ファラデー回転素子６０として例
えばＺｌＳｅを使用していたが、次のような問題があっ
た。In the magnetic field sensor described above, ZlSe, for example, was used as the Faraday rotary element 60, but there were the following problems.
■ セ／すが大型化する問題があった。■ There was a problem with the size of the center/su.
ＺｌＳｅのベルデ定数Ｖｅは０．１５ ｍ ｆｎ ／
ｏｅｃｍ（波長λ＝０．８５μｍ、温度２０℃）であり
、磁界に対する感度（変調度ｍ）を例えば磁界３０００
ｅに対して２チ程度得ようとすれば、Ｚｎ５ｅの長さｌ
が約５順程度必要であり、これ以上の感度を得ようとす
れば更にＺｌＳｅの長さｊを大きくしなければならず、
七／すが大型化した。The Verdet constant Ve of ZlSe is 0.15 m fn /
oecm (wavelength λ = 0.85 μm, temperature 20°C), and the sensitivity to the magnetic field (modulation degree m) is, for example, 3000
If you want to obtain about 2 inches for e, the length l of Zn5e
is required, and if you want to obtain higher sensitivity than this, the length j of ZlSe must be further increased,
7/The size has increased.
なお、変調度ｍとは磁界による光強度の変化率を意味し
、ｍ＝Ａｃ／ｐｃで表される（第４図参照）。Note that the modulation degree m means the rate of change in light intensity due to the magnetic field, and is expressed as m=Ac/pc (see FIG. 4).
ここで、ｋＧはファラデー回転素子に印加される交流電
流による交流磁界を意味し、またＤＣは入射光強度（一
定）を意味する。Here, kG means an alternating magnetic field due to an alternating current applied to the Faraday rotation element, and DC means the intensity of incident light (constant).
■ 温度による出力変化幅が大きく、測定誤差が生じる
問題があった。■ There was a problem that the range of output change due to temperature was large, resulting in measurement errors.
Ｚｎ５ｅは温度特性を有し、例えば温度を２０℃→＝１
０℃→６０℃→２０°Ｃと変化させたとき（第５図のグ
ラフ参照）出力変化幅が±２％程度と大きく（第５図の
グラフ参照）、精密磁界測定時に測定誤差の要因となっ
ていた。Zn5e has temperature characteristics, for example, when the temperature is changed from 20℃ to 1
When changing from 0°C to 60°C to 20°C (see the graph in Figure 5), the output variation range is as large as ±2% (see the graph in Figure 5), which may cause measurement errors when measuring precision magnetic fields. It had become.
（ハ）発明の目的
本発明は上記従来技術を解決するためになされたもので
、その目的とするところは、小型化することが出来ると
共に、温度による測定誤差を可及的に少なくすることが
出来る磁界センサを提供することである０
（ニ）発明の構成
本発明は、ファラデー効果を利用して磁界を測定する磁
界センサにおいて、ファラデー回転素子としてＣｄＺｎ
Ｔｅ （カドミウム・亜鉛・テルル）を用いたことを特
徴としている０
また、光進路に沿りて配置された偏光子、旋光子、ファ
ラデー回転素子及び検光子を含む磁界センサにおいて、
前記ファラデー回転素子に、ＣｄＺｎＴｅ（カドミウム
・亜鉛・テルル）を用いたことを特徴としている。(c) Purpose of the Invention The present invention has been made to solve the above-mentioned prior art, and its purpose is to reduce the size of the device and to reduce measurement errors due to temperature as much as possible. (d) Structure of the Invention The present invention provides a magnetic field sensor that measures a magnetic field using the Faraday effect, in which CdZn is used as a Faraday rotation element.
It is characterized by the use of Te (cadmium, zinc, tellurium)0 In addition, in a magnetic field sensor including a polarizer, a polarizer, a Faraday rotation element, and an analyzer arranged along the optical path,
The present invention is characterized in that CdZnTe (cadmium, zinc, tellurium) is used for the Faraday rotation element.
この発明で使用するＣｄ Ｚｎ Ｔｅは、ベルデ定数Ｖ
ｅが０．５２ ｍｉｎｌｏａｃｍ （波長λ＝ ０．８
５ μｍ、温度２０℃）と大きく、センサをＺｎ５ｅに
比して／」・型化することが出来る。また、温度特性に
つ−・ても−１０°Ｃ〜６０″Ｃの温度変化で出力変化
幅力１十０．５係と小さく、精密測定時に測定誤差を可
及的に少なく抑えることが出来る。Cd Zn Te used in this invention has a Verdet constant V
e is 0.52 minloacm (wavelength λ = 0.8
It is large (5 μm, temperature 20°C) and can be shaped into a sensor compared to Zn5e. In addition, the temperature characteristics are as small as 10.5 times the output change width with a temperature change of -10°C to 60''C, making it possible to keep measurement errors as low as possible during precision measurements. .
（ホ）発明の実施例
以下図面を参照して本発明の好ましく１実施例について
説明する。(E) Embodiment of the Invention A preferred embodiment of the invention will be described below with reference to the drawings.
第１図は本発明による磁界セ／すの構成を示す平面図で
ある。図中符号１は光源としてのＬＥＤ（発光ダイオー
ド）、２．１０は光ファイノく−１３，９はロッドレン
ズである。また、４は偏光子、５は旋光子、６はファラ
デー回転素子、８は検光子で、光進路に沿って配置され
ている。また、１１は光検出器としてのフォトダイオー
ド、１２はケースである０
この磁界センサの基本構成については、第３図に示すも
のとほぼ同じであるが、ここで重要な点は、ファラデー
回転素子６として、ＧｄＺｎＴｅ（カドミウム・亜鉛・
テルル）を用いた点である。このＣｄＺｎＴｅ（カドミ
ウム・亜鉛・テルル）は、ＣｄＴｅ（カドミウム・テル
ル）にＺｎ （亜鉛）を添加した伝導タイプがＰ型又は
Ｎ型の単結晶で、そのベルデ定数ｖｅは波長λ＝０．８
５μｍ１温度２０℃の下で、Ｖｅ ＝ ０．８５ ｍｌ
ｎｌｏｅｃｍであり、従来の磁界センサに使用されたＺ
ｎ Ｓｅ （Ｖｅ ＝ ０．１５ ｍｉｎｌｏｅｃｍ）
に比して約３倍大きい。従って、従来の磁界センサと同
一感度を得ようとすれば、ファラデー回転素子６の長さ
ｌを約１７３に縮小することができる。例えば、磁界３
０００ｅに対して感度を２多程度得ようとすれば、Ｚｎ
５ｅでは長さｌが約５ＥＩ程度必要であるのに対し、Ｃ
ｄＺｎＴｅでは長さｌが５寵Ｘ （０，ｌＬ５ ／ ０
．５２ ） ＝ １．４４ ｙａで済む。また、長さｌ
が同じならば、感度については約３倍大きくすることが
出来る０
また、温度特性については、第２図のグラフ（＠界７を
一定にして温度を変化させた時のファラデー回転角θの
変化、すなわちフォトダイオード１１の出力変化を表す
グラフ）に示すように、上記従来例と同様に温度を変化
させたとき出力変化幅が±０．５％であり、従来の磁界
センサ（同様の温度変化で出力変化幅が±２チ〜±４％
）に比して非常に小さく、このため精密磁界測定時にお
いてｆｆ１１１定誤差を可及的に少なくすることができ
る。FIG. 1 is a plan view showing the configuration of a magnetic field cell according to the present invention. In the figure, reference numeral 1 is an LED (light emitting diode) as a light source, 2, 10 is an optical fiber, 13, 9 is a rod lens. Further, 4 is a polarizer, 5 is an optical rotator, 6 is a Faraday rotation element, and 8 is an analyzer, which are arranged along the optical path. In addition, 11 is a photodiode as a photodetector, and 12 is a case. The basic configuration of this magnetic field sensor is almost the same as that shown in Fig. 3, but the important point here is that the Faraday rotation element 6, GdZnTe (cadmium, zinc,
The point is that tellurium) was used. This CdZnTe (cadmium-zinc-tellurium) is a single crystal with P-type or N-type conductivity, which is made by adding Zn (zinc) to CdTe (cadmium-tellurium), and its Verdet constant ve is at the wavelength λ = 0.8.
5μm 1 under temperature 20℃, Ve = 0.85 ml
nloecm and used in conventional magnetic field sensors
n Se (Ve = 0.15 minloecm)
It is about 3 times larger than . Therefore, in order to obtain the same sensitivity as a conventional magnetic field sensor, the length l of the Faraday rotation element 6 can be reduced to about 173. For example, magnetic field 3
If you want to obtain a sensitivity of 2 or more for 000e, Zn
In 5e, the length l is required to be about 5EI, whereas in C
In dZnTe, the length l is 5 x (0, lL5 / 0
．． 52) = 1.44 ya. Also, the length l
If the values are the same, the sensitivity can be increased by about 3 times.0 Also, regarding the temperature characteristics, see the graph in Figure 2 (Change in the Faraday rotation angle θ when the temperature is changed while keeping the field 7 constant). , that is, a graph representing the output change of the photodiode 11), when the temperature is changed in the same way as in the conventional example, the output change width is ±0.5%. The output change range is ±2 to ±4%.
), and therefore the ff111 constant error can be minimized as much as possible during precision magnetic field measurement.
上記磁界センサによると、ＬＥＤｌからの光は光ファイ
バー２を通ってロッドレンズ３で集光された後、偏光子
４に入射し、ここで無偏光の光（偏光方向が特定されず
、ランダムな偏光方向をもつ光）から直線偏光となり、
旋光子４を通ってファラデー回転素子６に入射する。直
線偏光は、このファラデー回転素子６を透過する間に磁
界７の影響により偏波面が角度θだげ回転され、そして
検光子８で光強度に変換され、ロッドレンズ９で集光さ
れた後、光ファイバー１０により光検出器であるフォト
ダイオード１１に導かれる。According to the above magnetic field sensor, the light from the LED 1 passes through the optical fiber 2 and is focused by the rod lens 3, and then enters the polarizer 4, where the light is unpolarized (the polarization direction is not specified and is randomly polarized). (directed light) becomes linearly polarized light,
The light passes through the optical rotator 4 and enters the Faraday rotation element 6 . While the linearly polarized light passes through the Faraday rotation element 6, the plane of polarization is rotated by an angle θ due to the influence of the magnetic field 7, and after being converted into light intensity by the analyzer 8 and condensed by the rod lens 9, The light is guided by an optical fiber 10 to a photodiode 11 which is a photodetector.
なお、偏光子４とファラデー回転素子６との間に旋光子
５を設置したのは、検光子８を偏光子４に対し光軸に関
して４５°ずらせて、回転角θに比例する光強度変化を
受けた光が検光子８から出射するようにするため、すな
わち磁界に比例した出力が得られるようにするためであ
る。ここで、旋光子５は４５°の旋光能を持つ長さに設
定されているＱ
磁界センサの構成については、上記のように偏光子４、
旋光子５、ファラデー回転素子６、検光子８を光進路に
沿って配置するタイプ以外のもの、例えば反射型タイプ
のものにも適用することが出来る。要はファラデー回転
素子を使用した磁界センサに広く適用することが出来る
。The reason for installing the optical rotator 5 between the polarizer 4 and the Faraday rotation element 6 is to shift the analyzer 8 by 45 degrees with respect to the optical axis with respect to the polarizer 4, so that the change in light intensity proportional to the rotation angle θ is detected. This is to ensure that the received light is emitted from the analyzer 8, that is, to obtain an output proportional to the magnetic field. Here, the length of the optical rotator 5 is set to have an optical rotation power of 45°. Regarding the configuration of the magnetic field sensor, as described above, the polarizer 4,
It is also possible to apply to a type other than the type in which the optical rotator 5, the Faraday rotation element 6, and the analyzer 8 are arranged along the optical path, for example, a reflective type. In short, it can be widely applied to magnetic field sensors using Faraday rotation elements.
（へ）発明の効果
以上のように本発明はファラデー回転素子として、Ｃｄ
ＺｎＴｅ （カドミウム・亜鉛・テルル）を用いている
ので、小型化することが出来ると共に、温度による測定
誤差？可及的に少なくすることが出来る。(f) Effects of the invention As described above, the present invention can be used as a Faraday rotation element.
Since it uses ZnTe (cadmium, zinc, tellurium), it can be made smaller and there is no measurement error due to temperature. It can be reduced as much as possible.
第１図及び第２図は本発明の一実施例を示すもので、第
１図は本発明による磁界センサの構成概念を示す平面図
、第２図はその温度特性を示すグラフであり、また第３
図乃至第５図は従来技術を示すもので、第３図は磁界セ
ンナの構成を示す概念図、第４図は変調度を説明する説
明図、第５図は温度特性を示すグラフである。
４・・・・偏光子、 ５・・・・旋光子、６．６０
・・・・ファラデー回転素子、８・・・・検光子。
特許出願人 住友電気工業株式会社
（外４名）
第３図
第４図
時間 −−
Ｎ
〜 −０−ＮＮ −ＯＮ1 and 2 show one embodiment of the present invention, FIG. 1 is a plan view showing the structural concept of the magnetic field sensor according to the invention, and FIG. 2 is a graph showing its temperature characteristics. Third
5 to 5 show the prior art. FIG. 3 is a conceptual diagram showing the configuration of a magnetic field sensor, FIG. 4 is an explanatory diagram illustrating the degree of modulation, and FIG. 5 is a graph showing temperature characteristics. 4... Polarizer, 5... Optical rotator, 6.60
...Faraday rotating element, 8...analyzer. Patent applicant Sumitomo Electric Industries, Ltd. (4 others) Figure 3 Figure 4 Time -- N ~ -0-NN -ON
Claims (2)
ンサにおいて、ファラデー回転素子としてＣｄＺｎＴｅ
（カドミウム・亜鉛・テルル）を用いたことを特徴とす
る磁界センサ。(1) In a magnetic field sensor that measures magnetic fields using the Faraday effect, CdZnTe is used as a Faraday rotation element.
A magnetic field sensor characterized by using (cadmium, zinc, tellurium).
ラデー回転素子及び検光子を含む磁界センサにおいて、
前記ファラデー回転素子に、ＣｄＺｎＴｅ（カドミウム
・亜鉛・テルル）を用いたことを特徴とする磁界センサ
。(2) In a magnetic field sensor including a polarizer, a polarizer, a Faraday rotation element, and an analyzer arranged along the optical path,
A magnetic field sensor characterized in that CdZnTe (cadmium, zinc, tellurium) is used for the Faraday rotation element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28586187A JPH01127984A (en) | 1987-11-12 | 1987-11-12 | Magnetic field sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28586187A JPH01127984A (en) | 1987-11-12 | 1987-11-12 | Magnetic field sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01127984A true JPH01127984A (en) | 1989-05-19 |
Family
ID=17697000
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28586187A Pending JPH01127984A (en) | 1987-11-12 | 1987-11-12 | Magnetic field sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01127984A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5790299A (en) * | 1995-12-15 | 1998-08-04 | Optics For Research | Optical isolator employing a cadmium-zinc-tellurium composition |
-
1987
- 1987-11-12 JP JP28586187A patent/JPH01127984A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5790299A (en) * | 1995-12-15 | 1998-08-04 | Optics For Research | Optical isolator employing a cadmium-zinc-tellurium composition |
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