JPH05141939A - Method and device for measuring change quantity of small angle - Google Patents
Method and device for measuring change quantity of small angleInfo
- Publication number
- JPH05141939A JPH05141939A JP10225291A JP10225291A JPH05141939A JP H05141939 A JPH05141939 A JP H05141939A JP 10225291 A JP10225291 A JP 10225291A JP 10225291 A JP10225291 A JP 10225291A JP H05141939 A JPH05141939 A JP H05141939A
- Authority
- JP
- Japan
- Prior art keywords
- angle
- crystal
- measuring
- polarizer
- change quantity
- 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
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は微小角度の変化量を測定
する方法及び装置に関する。詳しくは、本発明は、従来
の角度測定器に付加して使用することによって、さらに
微小な回転角度を高い精度で測定することが可能な微小
角度の変化量を測定する方法及び装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a minute angle change amount. More specifically, the present invention relates to a method and an apparatus for measuring a minute angle change amount that can be used in addition to a conventional angle measuring device to measure a further minute rotation angle with high accuracy.
【０００２】[0002]
【従来の技術】従来、回転角度の測定には、円筒状に、
はめあいを持つ二つの回転体が利用されている。このは
めあい部の円周方向に沿って目盛を刻印し、外側の回転
体を固定して、内側の回転体を基準となる位置から回転
させ、その時の回転角度を目盛から読み取る。2. Description of the Related Art Conventionally, a cylindrical shape has been used for measuring a rotation angle.
Two rotating bodies with fits are used. A scale is marked along the circumferential direction of the fitting portion, the outer rotating body is fixed, the inner rotating body is rotated from the reference position, and the rotation angle at that time is read from the scale.
【０００３】この方法の欠点は、回転体のはめあい部分
の加工精度によって、回転角度の測定精度が決まること
である。従って、測定精度が高くなる程、より高い加工
精度が要求され、また構造も複雑になると共に高価にな
る。更に、測定装置を使用する環境の変化（温度変化
等）や、使用年数によるはめあい部分の摩耗等により、
測定精度が異なる場合がある。The drawback of this method is that the accuracy of measurement of the rotation angle is determined by the processing accuracy of the fitting portion of the rotating body. Therefore, the higher the measurement accuracy, the higher the processing accuracy required, the more complicated the structure, and the more expensive. Furthermore, due to changes in the environment in which the measuring device is used (temperature changes, etc.) and wear of the fitting parts due to years of use,
The measurement accuracy may differ.
【０００４】[0004]
【発明が解決しようとする課題】本発明の目的は、微少
な回転角度の測定において、このような問題点を解消し
た方法及び装置を提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for solving such a problem in measuring a minute rotation angle.
【０００５】[0005]
【課題を解決するための手段】本願発明者は、この目的
達成のため鋭意研究の結果、結晶の回転角度が、結晶を
透過したレーザー光の偏光状態に与える影響を考察する
ことにより、簡素にしてコンパクトな微小回転角度の測
定方法及び装置を発明するに至った。As a result of earnest research aimed at achieving this object, the inventor of the present invention simplified the study by considering the effect of the rotation angle of the crystal on the polarization state of the laser beam transmitted through the crystal. And invented a compact and compact method and apparatus for measuring a minute rotation angle.
【０００６】本発明の測定方法及び装置を図１によって
説明する。本発明の結晶の複屈折性を利用した微少角度
を測定する装置は、レーザー光源１、レーザー光を所定
の方向に進行させるための反射鏡２及び３、複屈折性を
有する光学結晶素子４、これを紙面に垂直な軸のまわり
回転させるための回転ステージ５、該結晶素子透過後の
レーザー光の偏光状態を調べるための偏光子６、これを
光の進行方向に平行な軸の周りに回転させるための回転
ホルダー７、偏光子透過後のレーザー光の出力を測定す
るための出力測定器８、結晶に入射させる光の偏光度が
低い場合に、これを改善するための波長板９によって構
成される。The measuring method and apparatus of the present invention will be described with reference to FIG. The apparatus for measuring a minute angle utilizing the birefringence of crystals of the present invention includes a laser light source 1, reflecting mirrors 2 and 3 for advancing a laser beam in a predetermined direction, an optical crystal element 4 having birefringence, A rotating stage 5 for rotating this around an axis perpendicular to the plane of the paper, a polarizer 6 for examining the polarization state of the laser light after passing through the crystal element, and rotating this about an axis parallel to the light traveling direction. A rotating holder 7 for controlling the output, an output measuring device 8 for measuring the output of the laser light after passing through the polarizer, and a wavelength plate 9 for improving the polarization of the light incident on the crystal when the polarization is low. To be done.
【０００７】レーザー光が結晶素子４に入射すると、常
光線及び異常光線に分れて、結晶内部を進む。結晶透過
後のレーザー光の偏光状態は、これら常光線及び異常光
線の相互作用量によって変化する。この作用量は、結晶
回転ステージ５の角度θに対応している。When the laser light is incident on the crystal element 4, it is divided into an ordinary ray and an extraordinary ray and travels inside the crystal. The polarization state of the laser light after passing through the crystal changes depending on the amount of interaction between these ordinary rays and extraordinary rays. This amount of action corresponds to the angle θ of the crystal rotation stage 5.
【０００８】結晶透過後の光の偏光状態の把握は、偏光
子６と出力測定器８を用いて行う。偏光子透過後の光出
力が最大になるように、偏光子回転ホルダー７を回転さ
せた時の角度φを測定すると、回転ステージ５の角度θ
に対して、φは周期的に変化する値となる。更に、θの
変化量に対するφの変化量は数桁大きな値をとる。The polarization state of the light after passing through the crystal is grasped by using the polarizer 6 and the output measuring device 8. When the angle φ when the polarizer rotation holder 7 is rotated is measured so that the light output after passing through the polarizer is maximized, the angle θ of the rotation stage 5 is measured.
On the other hand, φ is a value that changes periodically. Furthermore, the amount of change in φ with respect to the amount of change in θ takes a value that is several orders of magnitude larger.
【０００９】この結果、偏光子回転ホルダー７の回転角
度φを測定することにより、結晶回転ステージ５の回転
角度θを知ることが可能になると共に，θ値の微少変化
量をそれよりも大きなφ値で知ることが可能になる。従
って、従来、角度を測定するための回転ステージに結晶
回転ステージ５を接合固定し、この装置を使用すること
によって回転角度の微少変化量を高い精度で測定するこ
とが可能になる。As a result, it becomes possible to know the rotation angle θ of the crystal rotation stage 5 by measuring the rotation angle φ of the polarizer rotation holder 7, and the minute change amount of the θ value is larger than that φ. It becomes possible to know by the value. Therefore, conventionally, by bonding and fixing the crystal rotation stage 5 to the rotation stage for measuring the angle and using this device, it becomes possible to measure the minute change amount of the rotation angle with high accuracy.
【００１０】[0010]
【実施例】本発明の一具体例を実験模式的に図２によっ
て説明する。光源１としてＹＡＧレーザーを用い、結晶
４としてＢＢＯを用いた。レーザー光は、反射鏡２及び
３を通って結晶４に導かれ、更に偏光子６を透過して、
出力測定器８に至る。結晶回転ステージ５の回転角度を
θ、偏光子回転ホルダー７の角度をφとして、測定した
結果は図３に示した。図において、横軸は結晶素子の回
転角度θで、縦軸は偏光子の回転角度φである。実線は
実験値で、破線は計算値を示した。θに対するφの変化
量として、１：３５０が得られた。この結果、１０秒の
測定精度を有する従来の偏光子回転ホルダーを用いれ
ば、８ｘ１０−６度までの回転角度微少変化量を測定す
ることが可能になることがわかった。EXAMPLES A specific example of the present invention will be schematically described by experiment with reference to FIG. A YAG laser was used as the light source 1, and BBO was used as the crystal 4. The laser light is guided to the crystal 4 through the reflecting mirrors 2 and 3, and further passes through the polarizer 6,
It reaches the output measuring device 8. The rotation angle of the crystal rotation stage 5 is θ and the angle of the polarizer rotation holder 7 is φ, and the measurement results are shown in FIG. In the figure, the horizontal axis is the rotation angle θ of the crystal element, and the vertical axis is the rotation angle φ of the polarizer. The solid line is the experimental value, and the broken line is the calculated value. The amount of change of φ with respect to θ was 1: 350. As a result, it was found that it is possible to measure the minute change amount of the rotation angle up to 8 × 10 −6 degrees by using the conventional polarizer rotation holder having the measurement accuracy of 10 seconds.
【図１】本発明の概要を示す説明図である。FIG. 1 is an explanatory diagram showing an outline of the present invention.
【図２】本発明の一具体例の実験模式図である。FIG. 2 is a schematic diagram of an experiment of a specific example of the present invention.
【図３】実施例の実験結果及び計算結果を示すグラフで
ある。FIG. 3 is a graph showing an experimental result and a calculation result of the example.
１ レーザー光源 ２ 反射鏡 ３ 反射鏡 ４ 複屈折性を有する結晶素子 ５ 回転ステージ ６ 偏光子 ７ 回転ホルダー ８ 出力測定器 ９ 波長板 1 Laser Light Source 2 Reflecting Mirror 3 Reflecting Mirror 4 Birefringent Crystal Element 5 Rotating Stage 6 Polarizer 7 Rotating Holder 8 Output Measuring Instrument 9 Wave Plate
Claims (2)
たレーザー光の結晶回転角度に対する偏光状態の変化か
ら該回転角度を測定することから成る微小角度の変化量
を測定する方法。1. A method for measuring a minute angle change amount, which comprises measuring a rotation angle of a laser beam transmitted through a crystal optical element having birefringence with respect to a crystal rotation angle.
に進行させるための反射鏡、結晶光学素子及び該素子を
固定した回転ステージ、偏光子及び該偏光子をレーザー
光の進行方向に平行な軸の周りに回転させるための回転
ホルダー及び偏光子透過後のレーザー光の出力を測定す
るための出力測定器から成る微小角度の変化量を測定す
る装置。2. A laser light source, a reflecting mirror for advancing laser light in a predetermined direction, a crystal optical element and a rotary stage on which the element is fixed, a polarizer and an axis parallel to the laser light advancing direction. A device for measuring the amount of change in a minute angle, which comprises a rotating holder for rotating around the lens and an output measuring device for measuring the output of the laser light after passing through the polarizer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10225291A JPH05141939A (en) | 1991-02-08 | 1991-02-08 | Method and device for measuring change quantity of small angle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10225291A JPH05141939A (en) | 1991-02-08 | 1991-02-08 | Method and device for measuring change quantity of small angle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05141939A true JPH05141939A (en) | 1993-06-08 |
Family
ID=14322410
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10225291A Pending JPH05141939A (en) | 1991-02-08 | 1991-02-08 | Method and device for measuring change quantity of small angle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05141939A (en) |
-
1991
- 1991-02-08 JP JP10225291A patent/JPH05141939A/en active Pending
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