JP3456695B2 - Birefringence measuring method and apparatus therefor - Google Patents
Birefringence measuring method and apparatus thereforInfo
- Publication number
- JP3456695B2 JP3456695B2 JP08300799A JP8300799A JP3456695B2 JP 3456695 B2 JP3456695 B2 JP 3456695B2 JP 08300799 A JP08300799 A JP 08300799A JP 8300799 A JP8300799 A JP 8300799A JP 3456695 B2 JP3456695 B2 JP 3456695B2
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- JP
- Japan
- Prior art keywords
- light
- light receiving
- birefringence
- optical system
- transmitted
- Prior art date
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、レーザプリンタ等
に用いられる光書込用或いはピックアップ用などに用い
られるプラスチックスレンズ等のプラスチック製品なる
被検物の複屈折を測定する複屈折測定方法及びその装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a birefringence measuring method for measuring the birefringence of a test object made of a plastic product such as a plastic lens used for optical writing or pickup used in a laser printer or the like. Regarding the device.
【０００２】[0002]
【従来の技術】従来、この種の被検レンズ等の被検物に
関する複屈折の測定方法としては、位相変調法や回転検
光子法が知られている。これらの方法にあっては、透明
な被検物に細い平行ビームを照射し、被検物からの透過
光をフォトダイオード等の受光素子で受光し、被検物の
複屈折による透過光の偏光状態の変化を検出することに
より、被検物の複屈折を求めるものである。2. Description of the Related Art Conventionally, a phase modulation method and a rotation analyzer method have been known as methods of measuring birefringence of an object such as a lens to be inspected. In these methods, a transparent parallel beam is radiated onto a test object, the transmitted light from the test object is received by a light receiving element such as a photodiode, and the transmitted light is polarized by birefringence of the test object. The birefringence of the test object is obtained by detecting the change in the state.
【０００３】位相変調法では、「光技術コンタクト」Ｖ
ol.27.No.3(1989)中の「位相変調法による複屈折 測定
と応用」p.127〜p.134等により報告されているように、
光弾性変調器（ＰＥＭ）を利用して照射光を位相変調さ
せ、透明な被検物を透過した光のビート信号と変調信号
との位相から複屈折を求めるようにしている。In the phase modulation method, "optical technology contact" V
ol.27.No.3 (1989) `` Measurement and application of birefringence by phase modulation method '' p.127-p.134, etc.
The irradiation light is phase-modulated by using a photoelastic modulator (PEM), and the birefringence is obtained from the phase of the beat signal and the modulation signal of the light transmitted through the transparent test object.
【０００４】回転検光子法では、「光学的測定ハンドブ
ック」(1981年7月25日発刊）田幸敏治、辻内順平、南茂
夫編、朝倉書店中の「偏光解析」p.256〜p.265等に報告
されているように、透明な被検物の背面に置いた検光子
を回転させながら検光子の背面の受光素子で透過光を受
光し、検光子の回転に伴う受光素子からの受光出力の変
化により複屈折を求めるようにしている。In the rotation analyzer method, "Optical Measurement Handbook" (published on July 25, 1981) Toshiharu Tayuki, Junpei Tsujiuchi, Shigeo Minami, "Polarization Analysis" p.256-p.265 in Asakura Shoten. As reported in, the transmitted light is received by the light receiving element on the back side of the analyzer while rotating the analyzer placed on the back side of the transparent object, and the received light output from the light receiving element accompanying the rotation of the analyzer. The birefringence is determined by the change of.
【０００５】さらに、特開平４−５８１３８号公報、特
開平７−７７４９０号公報等によれば、拡大した平行光
を透明な被検物に照射し、その透過光をＣＣＤカメラ等
の２次元センサで受光することにより、被検物の複屈折
を求めるようにしており、複屈折の面計測を可能として
いる。Further, according to JP-A-4-58138 and JP-A-7-77490, a magnified parallel light is irradiated onto a transparent object, and the transmitted light is transmitted through a two-dimensional sensor such as a CCD camera. The birefringence of the object to be inspected is obtained by receiving the light by, and the surface of the birefringence can be measured.
【０００６】[0006]
【発明が解決しようとする課題】位相変調法、回転偏光
子法は、何れも、例えば細い平行ビームを被検物に照射
しフォトダイオードで受光する、という所謂“点計測”
であるため、被検物の全面を測定するには被検物や測定
装置を調整する必要があり、特にレンズのような非平板
を被検物とするような場合には、被検レンズに照射した
光ビームが被検レズで屈折されるため、被検物や測定装
置のセッティングが複雑かつ困難である。Both the phase modulation method and the rotating polarizer method are so-called "point measurement" in which, for example, a thin parallel beam is applied to an object to be detected and is received by a photodiode.
Therefore, in order to measure the entire surface of the object to be inspected, it is necessary to adjust the object to be inspected and the measuring device, and especially when using a non-flat plate such as a lens as the object to be inspected, Since the irradiated light beam is refracted by the test lens, setting of the test object and the measuring device is complicated and difficult.
【０００７】また、特開平４−５８１３８号公報によれ
ば、“面計測”であるため、被検物等の調整は不要であ
るものの、レーザプリンタ等で用いられる書込用プラス
チックレンズ（通常はｆθレンズ）などのように、一般
に高ＮＡ、大口径で非軸対称なものも多い測定対象の場
合、場所による屈折の度合いの差が大きく、透過光がけ
られたり重なったり、透過像が歪んだりするため、レン
ズの全面に渡って鮮明な透過像を得ることが難しく、全
面に渡っての正確な測定が困難である。Further, according to Japanese Patent Laid-Open No. 4-58138, since the "surface measurement" is performed, adjustment of an object to be inspected or the like is unnecessary, but a plastic lens for writing used in a laser printer or the like (usually In the case of measuring objects such as fθ lens) that generally have a high NA, a large aperture and are non-axisymmetric, the difference in the degree of refraction depending on the location is large and the transmitted light is eclipsed or overlapped, and the transmitted image is distorted. Therefore, it is difficult to obtain a clear transmission image over the entire surface of the lens, and it is difficult to perform accurate measurement over the entire surface.
【０００８】さらに、これらの測定方法は、測定に使用
する光源の波長により測定レンジが制限されるため、被
検物の厚みが大きい場合、得られる測定値に光源波長に
起因する不確定性が含まれてしまう不具合がある。具体
的な提案例としては、例えば、特開平４−５８１３８号
公報等によれば、拡大した平行光を透明な被検物に照射
し、その透過光をＣＣＤカメラ等の２次元センサで受光
することにより、被検物の複屈折を求めるようにしてい
るが、複屈折の測定結果が、複屈折位相差にして０〜λ
／４（λ：光源波長）の範囲内で得られるため、その範
囲を越える複屈折位相差の測定結果は不確定となる。つ
まり、複屈折位相差の測定値をδとし、真の複屈折位相
差をδ′とした場合、
δ′＝ｍ・λ／２±δ（ｍ：整数）
なる関係となり、整数ｍの値が不確定となる。結局、特
開平４−５８１３８号公報例では、光源波長λにより測
定範囲が決まってしまうため、測定範囲を越えるような
大きな複屈折には対応できず、かつ、複屈折分布が測定
範囲を越える場合も同様に対応できない。特にレーザプ
リンタ等で用いられる光書込み系用のプラスチックレン
ズは、小径のプラスチックレンズ、或いは光ディスクに
比べて肉厚が厚く光源波長で決まる測定範囲を上回るよ
うな複屈折及び複屈折分布を持つ場合も十分に考えられ
る。このようなことから、複屈折測定方法としては、光
源波長による制約を受けることなく、大きな複屈折の測
定が可能であることが要求される。Further, in these measuring methods, since the measuring range is limited by the wavelength of the light source used for measurement, when the thickness of the test object is large, there is uncertainty in the obtained measured value due to the light source wavelength. There is a problem that it is included. As a concrete proposal example, for example, according to Japanese Patent Laid-Open No. 4-58138, etc., a transparent parallel object is irradiated with enlarged parallel light, and the transmitted light is received by a two-dimensional sensor such as a CCD camera. By doing so, the birefringence of the test object is determined.
Since it is obtained within the range of / 4 (λ: light source wavelength), the measurement result of the birefringence phase difference exceeding that range becomes uncertain. That is, when the measured value of the birefringence phase difference is δ, and the true birefringence phase difference is δ ′, the relationship is δ ′ = m · λ / 2 ± δ (m: integer), and the value of the integer m is Uncertain. After all, in the example of Japanese Patent Laid-Open No. 4-58138, the measurement range is determined by the light source wavelength λ, so that it is not possible to cope with a large birefringence that exceeds the measurement range, and the birefringence distribution exceeds the measurement range. Can't do the same. In particular, a plastic lens for optical writing system used in a laser printer or the like may have a small diameter plastic lens, or may have a birefringence and a birefringence distribution which are thicker than an optical disc and exceed the measurement range determined by the light source wavelength. Well thought out. For this reason, the birefringence measuring method is required to be capable of measuring large birefringence without being restricted by the wavelength of the light source.
【０００９】そこで、本発明は、被検物表面における汚
れ等のノイズの影響を受けにくい良好なる複屈折の測定
が可能な複屈折測定方法及びその装置を提供することを
目的とする。Therefore, it is an object of the present invention to provide a birefringence measuring method and an apparatus therefor capable of excellent birefringence measurement which is hardly affected by noise such as stains on the surface of an object to be inspected.
【００１０】また、複数の受光素子を並設させてなる受
光素子アレイを利用することで、短時間、かつ、高い空
間分解能での複屈折測定が可能な複屈折測定装置を提供
することを目的とする。Another object of the present invention is to provide a birefringence measuring apparatus which can measure birefringence in a short time with high spatial resolution by utilizing a light receiving element array in which a plurality of light receiving elements are arranged in parallel. And
【００１１】また、被検物がレンズのように曲率をもつ
場合、被検物を透過する光の屈折の仕方が場所によって
異なるため、全ての透過光を受光素子に導くには、複雑
な構成や調整が必要となり、操作性が悪い上に時間がか
かるという問題があるので、本発明は、被検物がレンズ
のように曲率をもつ場合でも、簡単、短時間、かつ、高
い空間分解能で高精度な測定が可能な複屈折測定装置を
提供することを目的とする。Further, when the object to be inspected has a curvature like a lens, the way of refracting the light passing through the object to be inspected differs depending on the place. Therefore, it is complicated to guide all the transmitted light to the light receiving element. Since there is a problem that operability and adjustment are required, and the operability is poor and it takes time, the present invention is simple, short time, and has high spatial resolution even when the test object has a curvature like a lens. It is an object of the present invention to provide a birefringence measuring device capable of highly accurate measurement.
【００１２】また、被検物がレンズの場合は、その種類
によって焦点距離が異なり、さらに非軸対称レンズの場
合は直交方向で各々の焦点距離が異なる状況があるが、
本発明は、このような被検レンズの種類の変更に対する
汎用性を高め得る複屈折測定装置を提供することを目的
とする。Further, when the object to be inspected is a lens, the focal length differs depending on the type, and in the case of a non-axisymmetric lens, there are situations in which the focal lengths differ in the orthogonal direction.
It is an object of the present invention to provide a birefringence measuring device that can enhance versatility with respect to such a change in the type of lens under test.
【００１３】加えて、本発明は、位置、配置の設定変更
を自動化することで、装置の操作性を向上させ得る複屈
折測定装置を提供することを目的とする。In addition, an object of the present invention is to provide a birefringence measuring device capable of improving the operability of the device by automating the setting change of the position and the arrangement.
【００１４】また、被検物の面積が大きい場合、被検物
の全面に対して透過した光束を一度に受光しようとする
と、透過像を光学的に縮小する必要があり、測定の空間
的な分解能が落ちる。透過像を光学的に縮小せず被検物
の透過光束を一度に受光しようとすると大きな面積の偏
光素子、受光素子が必要となりコストがかかるという問
題があるが、本発明は、被検物全面に渡って、高い空間
分解能での測定が可能な複屈折測定方法及びその装置を
提供することを目的とする。Further, when the area of the object to be inspected is large, it is necessary to optically reduce the transmission image when attempting to receive the light flux transmitted through the entire surface of the object to be inspected at one time, which results in spatial measurement. The resolution drops. If it is attempted to receive the transmitted light flux of the test object at one time without optically reducing the transmitted image, there is a problem in that a polarizing element and a light receiving element having a large area are required, and the cost is high. It is an object of the present invention to provide a birefringence measuring method and apparatus capable of measuring with high spatial resolution.
【００１５】加えて、本発明は、被検物が焦点距離の短
いレンズの場合であっても、被検物全面に渡って、高い
空間分解能での測定が可能な複屈折測定方法及びその装
置を提供することを目的とする。In addition, the present invention provides a birefringence measuring method and apparatus capable of measuring with high spatial resolution over the entire surface of the object to be measured even when the object is a lens having a short focal length. The purpose is to provide.
【００１６】同様に、本発明は、被検物が平行平板或い
は焦点距離の長いレンズ場合であっても、被検物全面に
渡って、高い空間分解能での測定が可能な複屈折測定方
法及びその装置を提供することを目的とする。併せて、
被検物が焦点距離の長いレンズの測定においては装置の
小型化を図ることを目的とする。Similarly, the present invention provides a birefringence measuring method and a birefringence measuring method capable of performing measurement with high spatial resolution over the entire surface of an object to be measured even when the object is a parallel plate or a lens having a long focal length. The purpose is to provide the device. together,
The object of the present invention is to reduce the size of the device when measuring a lens whose test object has a long focal length.
【００１７】また、上記目的を実現するために、分割測
定を実施する場合、被検物表面に光学系光軸方向への凹
凸（奥行き）があると、場所によって被検物表面と受光
素子との結像関係が成立しなくなり、画像がぼけるた
め、正確な複屈折情報が得られないという問題を生じ得
るが、本発明は、このような状況下でも、被検物の全面
に渡っての正確な測定が可能な複屈折測定方法及びその
装置を提供することを目的とする。Further, in order to achieve the above object, when performing the divided measurement, if there is unevenness (depth) in the optical system optical axis direction on the surface of the object to be measured, the surface of the object to be detected and the light receiving element may be different depending on the location. However, since the image forming relationship is not established and the image is blurred, accurate birefringence information cannot be obtained. However, the present invention can be applied to the entire surface of the test object even in such a situation. It is an object of the present invention to provide a birefringence measuring method and an apparatus therefor capable of performing accurate measurement.
【００１８】また、測定レンジが使用する光源波長によ
って制限され、それを越えるような大きな複屈折の位相
差測定結果には、光源波長に起因する不確定性が含まれ
るという問題を生ずるが、本発明は、光源波長に制限さ
れない（無限大の）広い測定レンジを得ることができる
複屈折測定方法及びその装置を提供することを目的とす
る。Further, the measurement range is limited by the wavelength of the light source used, and a large birefringence phase difference measurement result exceeding the range causes a problem that the uncertainty due to the wavelength of the light source is included. An object of the present invention is to provide a birefringence measuring method and an apparatus therefor capable of obtaining a wide (infinite) measuring range which is not limited to a light source wavelength.
【００１９】さらに、上記目的を実現する上で、被検領
域内において被検物の複屈折の変化が大きい場合、被検
物の透過光束にて形成される２次元的な明暗分布（光弾
性干渉縞）の明るい部分同士の間隔、或いは暗い部分同
士の間隔（干渉縞間隔）が狭くなり、その間隔が単一の
受光素子のサイズより小さくなり、測定レンジの拡大を
正確に実施できなくなってしまう不具合を生じ得ること
があるが、本発明は、被検領域内において被検物の複屈
折の変化が大きい場合であっても、測定レンジの拡大を
実現し得る複屈折測定方法及びその装置を提供すること
を目的とする。Further, in order to achieve the above object, when the change in birefringence of the test object is large in the test area, a two-dimensional light-dark distribution (photoelasticity) formed by the transmitted light flux of the test object is obtained. The interval between the bright parts of the interference fringes or the interval between the dark parts (interference fringe interval) becomes narrower, and the interval becomes smaller than the size of a single light receiving element, so that the measurement range cannot be expanded accurately. However, the present invention provides a birefringence measuring method and apparatus capable of expanding the measurement range even when the change in the birefringence of the test object in the test area is large. The purpose is to provide.
【００２０】また、上記目的を実現する上で、光源波長
に制限されない広い測定レンジを得る場合、処理に時間
がかかり、また、処理誤差も生ずる不具合を生じ得る
が、本発明は、−λ／４〜＋λ／４なる測定レンジを−
λ／2〜＋λ／2まで拡大する処理を、短時間で、かつ、
処理誤差を完全になくして実現し得る複屈折測定方法及
びその装置を提供することを目的とする。In order to achieve the above object, when a wide measurement range not restricted by the wavelength of the light source is obtained, it takes a long time for processing and a processing error may occur. However, the present invention provides -λ / 4 to + λ / 4 measurement range-
Processing for expanding from λ / 2 to + λ / 2 in a short time
An object of the present invention is to provide a birefringence measuring method and an apparatus therefor which can be realized without completely eliminating a processing error.
【００２１】また、上述の目的を実現する複屈折測定装
置においては、被検２次元領域において基準と設定した
位置での複屈折位相差測定値に対する任意位置での複屈
折位相差の変化分（位相差分布）が、２次元空間分布と
して得られる。言い換えると基準位置での複屈折測定値
に対する比較測定となる。従って、基準位置での複屈折
位相差測定値が、既に、使用光源波長にて決まる測定範
囲を超えている可能性もあるので、当該複屈折測定装置
による測定値は複屈折位相差の絶対値とは必ずしもいえ
ない。そこで、本発明は、被検空間における基準と設定
した位置での複屈折位相差の絶対値を測定、或いは推定
しておき、２次元空間分布の測定結果と組み合わせるこ
とで、被検領域全体における複屈折位相差の絶対値を判
断可能にする複屈折測定方法及びその装置を提供するこ
とを目的とする。Further, in the birefringence measuring apparatus which realizes the above-mentioned object, the change amount of the birefringence phase difference at an arbitrary position with respect to the birefringence phase difference measurement value at the position set as the reference in the two-dimensional region to be measured ( Phase difference distribution) is obtained as a two-dimensional spatial distribution. In other words, it is a comparative measurement with respect to the birefringence measurement value at the reference position. Therefore, since the birefringence phase difference measurement value at the reference position may already exceed the measurement range determined by the used light source wavelength, the measurement value by the birefringence measurement device concerned is the absolute value of the birefringence phase difference. Not necessarily. Therefore, in the present invention, the absolute value of the birefringence phase difference at the position set as the reference in the test space is measured or estimated, and combined with the measurement result of the two-dimensional spatial distribution to determine the entire test region. An object of the present invention is to provide a birefringence measuring method and an apparatus therefor capable of determining the absolute value of the birefringence phase difference.
【００２２】さらに、光書き込み系は、実使用では複数
のレンズにて構成されることが多い点に着目し、本発明
は、それらが光学系として組みあがった状態であって
も、前述した測定に対応可能な複屈折測定装置を提供す
ることを目的とする。Further, focusing on the fact that the optical writing system is often composed of a plurality of lenses in actual use, the present invention provides the above-mentioned measurement even when they are assembled as an optical system. It is an object of the present invention to provide a birefringence measuring device that can handle the above.
【００２３】[0023]
【課題を解決するための手段】請求項１記載の発明の複
屈折測定方法は、ほぼ円偏光を被検物に対して照射し、
前記被検物を透過した光束を検光子のみを介して受光手
段により受光するとともに前記検光子を回転させたとき
に得られる光強度変化より求めた被検物透過光の偏光情
報と、前記被検物を透過した光束を移相子と前記検光子
とを介して前記受光手段により受光するとともに前記検
光子を回転させたときに得られる光強度変化より求めた
被検物透過光の偏光情報との、両偏光情報に基づき前記
被検物の複屈折を求めるようにした。この場合、任意に
設定した被検領域内での基準位置における複屈折位相差
の絶対量を推定し、推定された複屈折位相差の絶対量を
測定された複屈折位相差の２次元空間分布の測定値全て
に適用して被検領域全体における複屈折位相差の絶対量
を測定することで、２次元被検領域全体における複屈折
位相差の絶対値が判断可能となる。また、請求項２記載
の発明は、請求項１記載の複屈折測定方法において、前
記移相子を光学系光軸以外の方向に進退させることで、
前記被検物から前記受光手段までの光路に前記移相子が
介在される状態と介在されない状態とを生成するように
した。 The birefringence measuring method of the invention according to claim 1 irradiates a test object with substantially circularly polarized light,
Polarization information of the transmitted light of the test object obtained from the light intensity change obtained when the light beam that has passed through the test object is received by the light receiving means only through the analyzer and the analyzer is rotated, and Polarization information of the transmitted light of the test object obtained from the light intensity change obtained when the light beam that has passed through the test object is received by the light receiving means through the phase shifter and the analyzer and the analyzer is rotated. And the birefringence of the test object is obtained based on both polarization information. In this case,
Birefringence phase difference at the reference position within the set test area
Estimate the absolute amount of
All measured values of the two-dimensional spatial distribution of the measured birefringence retardation
Applied to the absolute amount of birefringence retardation in the entire region under test
By measuring the birefringence in the entire two-dimensional test area
The absolute value of the phase difference can be determined. The invention according to claim 2 is the birefringence measuring method according to claim 1, wherein the retarder is moved back and forth in a direction other than the optical axis of the optical system.
A state in which the retarder is interposed and a state in which the retarder is not interposed are generated in the optical path from the test object to the light receiving means .
【００２４】従って、これらの請求項１、２記載の発明
によれば、被検物表面における汚れ等のノイズの影響を
受けにくい複屈折の測定が可能となる。[0024] Therefore, according to these claims 1, 2 SL placing of the invention, it is possible to measure the susceptible birefringence effect of noise such as dirt in the surface of the test object.
【００２５】請求項３記載の発明の複屈折測定装置は、
被検物に対してほぼ円偏光を照射するための光源と、前
記被検物を透過した透過光の偏光状態を変化させる移相
子と、この移相子を透過した光の偏光状態を検知するた
めの検光子と、この検光子を透過した光を受光する複数
の受光素子が並設された受光素子アレイよりなる受光手
段と、前記被検物を透過した透過光の光束を常に光軸に
対してほぼ平行にするための照射光学系と、前記被検物
を透過した光を前記受光素子アレイの受光面上に結像さ
せるための結像光学系と、前記被検物から前記受光手段
までの光路上に前記移相子が介在される状態と介在され
ない状態とを生成する移相子進退切換手段と、前記検光
子をその光軸回りに回転させる回転手段と、この回転手
段による 前記検光子の回転角度を検知する回転角検知手
段と、前記被検物を保持する保持手段と、前記受光手段
により受光検出される受光出力と前記回転角検知手段に
より検知された回転角度とに基づき前記被検物の複屈折
を算出する演算手段と、を備え、前記照射光学系が、組
合せ自在な複数の光学系よりなる。 The birefringence measuring apparatus according to the invention of claim 3 is
A light source for irradiating the subject with almost circularly polarized light,
Phase shift that changes the polarization state of transmitted light that has passed through the test object
And the polarization state of the light transmitted through this retarder.
Analyzer and a plurality of detectors that receive the light transmitted through this analyzer.
Receiver consisting of a light-receiving element array in which the light-receiving elements of
And the luminous flux of the transmitted light that has passed through the test object is always on the optical axis.
An irradiation optical system for making them substantially parallel to each other, and the object to be inspected
The light transmitted through is imaged on the light receiving surface of the light receiving element array.
Image forming optical system for moving the object, and the light receiving means from the object to be measured.
The phase shifter is interposed in the optical path up to
And a phase shifter advancing / retreating switching means for generating
Rotating means for rotating the child around its optical axis and this rotating hand
Rotation angle detection hand for detecting the rotation angle of the analyzer by the step
A step, a holding means for holding the test object, and the light receiving means
The received light output detected by the
Birefringence of the object based on the detected rotation angle and
Calculating means for calculating
It consists of multiple optical systems that can be combined.
【００２６】従って、前記受光手段が複数の受光素子が
並設された受光素子アレイよりなることから、短時間か
つ高い空間分解能での複屈折測定が可能となる。また、
前記被検物を透過した透過光の光束を常に光軸に対して
ほぼ平行にするための照射光学系と、前記被検物を透過
した光を前記受光素子アレイの受光面上に結像させるた
めの結像光学系とを備えることから、被検物がレンズの
ように曲率をもつ場合でも簡単、短時間、高い空間分解
能で、かつ、高精度な測定が可能となる。そして、前記
照射光学系が組合せ自在な複数の光学系よりなることか
ら、被検レンズの種類の変更に対する汎用性を高めるこ
とができる。 Therefore, the light receiving means includes a plurality of light receiving elements.
Since it is composed of light receiving element arrays arranged in parallel,
Birefringence measurement with high spatial resolution is possible. Also,
The luminous flux of the transmitted light that has passed through the test object is always aligned with the optical axis.
Irradiation optics for making them almost parallel and transmission through the test object
The formed light is focused on the light receiving surface of the light receiving element array.
Image-forming optical system for
Simple, short time, high spatial resolution even with curvature
It is possible to measure with high accuracy. And said
Is the irradiation optical system composed of multiple freely combinable optical systems?
To improve versatility for changing the type of lens under test.
You can
【００２７】請求項４〜１１記載の発明の複屈折測定装
置は、被検物に対してほぼ円偏光を照射するための光源
と、前記被検物を透過した透過光の偏光状態を変化させ
る移相子と、この移相子を透過した光の偏光状態を検知
するための検光子と、この検光子を透過した光を受光す
る複数の受光素子が並設された受光素子アレイよりなる
受光手段と、前記被検物を透過した透過光の光束を常に
光軸に対してほぼ平行にするための照射光学系と、前記
被検物を透過した光を前記受光素子アレイの受光面上に
結像させるための結像光学系と、前記被検物から前記受
光手段までの光路上に前記移相子が介在される状態と介
在されない状態とを生成する移相子進退切換手段と、前
記検光子をその光軸回りに回転させる回転手段と、この
回転手段による前記検光子の回転角度を検知する回転角
検知手段と、前記被検物を保持する保持手段と、前記受
光手段により受光検出される受光出力と前記回転角検知
手段により検知された回転角度とに基づき前記被検物の
複屈折を算出する演算手段と、を備える。これにより、
前記受光手段が複数の受光素子が並設された受光素子ア
レイよりなることから、短時間かつ高い空間分解能での
複屈折測定が可能となる。また、前記被検物を透過した
透過光の光束を常に光軸に対してほぼ平行に するための
照射光学系と、前記被検物を透過した光を前記受光素子
アレイの受光面上に結像させるための結像光学系とを備
えることから、被検物がレンズのように曲率をもつ場合
でも簡単、短時間、高い空間分解能で、かつ、高精度な
測定が可能となる。 The birefringence measuring device according to any one of claims 4 to 11
Is a light source for irradiating the subject with almost circularly polarized light.
And changing the polarization state of the transmitted light transmitted through the test object.
And the polarization state of the light transmitted through this retarder
And the light that has passed through this analyzer.
It consists of a light receiving element array in which multiple light receiving elements are arranged in parallel.
The light receiving means and the luminous flux of the transmitted light that has passed through the test object are always
An irradiation optical system for making it substantially parallel to the optical axis, and
The light transmitted through the object to be inspected is received on the light receiving surface of the light receiving element array.
An image forming optical system for forming an image and the receiving optical system from the test object.
The state and the interposition of the retarder on the optical path to the optical means.
An absent state and a phase shifter advancing / retreating switching means,
Rotating means for rotating the analyzer around its optical axis,
Rotation angle for detecting the rotation angle of the analyzer by the rotation means
Detection means, holding means for holding the test object, and the receiving means.
Received light output detected by light means and rotation angle detection
Based on the rotation angle detected by the means,
Arithmetic means for calculating birefringence. This allows
The light receiving means is a light receiving element array in which a plurality of light receiving elements are arranged in parallel.
Since it consists of rays, it is possible to obtain high spatial resolution in a short time.
Birefringence measurement is possible. In addition, the sample was transmitted
To substantially parallel light beams of the transmitted light always with respect to the optical axis
Irradiation optical system and the light receiving element for transmitting the light transmitted through the test object.
Image forming optical system for forming an image on the light receiving surface of the array
Therefore, if the test object has a curvature like a lens,
However, it is easy, short time, high spatial resolution, and highly accurate.
It becomes possible to measure.
【００２８】その上で、請求項４、５記載の発明は、前
記被検物に対する前記照射光学系の光軸方向の位置を移
動調整する移動手段と、前記照射光学系の光軸方向にお
ける位置を検知する検知手段と、を備える。従って、被
検レンズの種類の変更に対する汎用性を高めることがで
きる。請求項５記載の発明では、前記照射光学系が組合
せ自在な複数の光学系よりなることから、被検レンズの
種類の変更に対する汎用性を高めることができる。 In addition, the invention according to claims 4 and 5 is characterized in that the moving means for moving and adjusting the position of the irradiation optical system with respect to the test object in the optical axis direction, and the irradiation optical system. A detection unit that detects a position in the optical axis direction. Therefore, versatility with respect to the change of the type of the lens to be inspected can be enhanced. In the invention according to claim 5, the irradiation optical system is a combination.
Since it consists of multiple flexible optical systems,
The versatility for changing the type can be improved.
【００２９】請求項６、８記載の発明は、前記移相子、
検光子、受光素子アレイ、移相子進退切換手段、回転手
段、回転角検知手段及び結像光学系を一体にして搭載し
たベースと、このベースを光学系光軸とほぼ垂直方向に
移動させるベース移動手段と、このベース移動手段より
移動する前記ベースの光学系光軸と垂直方向における位
置を検知するベース位置検知手段と、を備える。 [0029] The invention of claim 6 and 8 wherein the pre KiUtsuri retarder,
A base on which an analyzer, a light-receiving element array, a phase shifter advancing / retreating switching means, a rotating means, a rotation angle detecting means, and an imaging optical system are integrally mounted, and a base for moving the base in a direction substantially perpendicular to the optical axis of the optical system. A moving means and a base position detecting means for detecting the position of the base moving from the base moving means in a direction perpendicular to the optical axis of the optical system are provided .
【００３０】請求項７、９記載の発明は、前記被検物を
保持する前記保持手段を光学系光軸とほぼ垂直方向に移
動させる保持手段移動手段と、この保持手段移動手段よ
り移動する前記保持手段の光学系光軸と垂直方向におけ
る位置を検知する保持手段位置検知手段と、を備える。
従って、被検物が焦点距離の長いレンズの測定において
は装置の小型化を図ることもできる。[0030] The invention of claim 7 and 9 wherein the pre-Symbol holding means moving means for moving the holding means for holding a specimen in a direction substantially perpendicular to the optical system optical axis, to move from the holding means moving means Holding means position detecting means for detecting the position of the holding means in the direction perpendicular to the optical axis of the optical system.
Therefore , the device can be downsized in the measurement of the lens whose test object has a long focal length.
【００３１】請求項１０記載の発明は、前記結像光学系
と前記受光素子アレイとを一体にして搭載した受光ベー
スを備える。 The invention of claim 10 wherein is provided with a receiving base mounted so as to be integrated with said light receiving element array and before Kiyuizo optics.
【００３２】請求項１１記載の発明は、前記結像光学系
の結像倍率が可変自在である。従って、被検領域内にお
いて被検物の複屈折の変化が大きい場合でも、測定レン
ジの拡大が可能となる。The invention of claim 11, wherein the imaging magnification of the pre Kiyuizo optical system is variable freely. Therefore, even when the change in birefringence of the test object is large in the test region, the measurement range can be expanded.
【００３３】[0033]
【発明の実施の形態】本発明の実施の形態を図面に基づ
いて説明する。図１は本実施の形態に用いる複屈折測定
装置の構成例を示すもので、例えばプラスチック製の軸
対称レンズ等の測定対象とする被検物１は保持手段とし
てのホルダ（図示せず）により保持される。このような
被検物１に対して、光源である半導体レーザ２からの直
線偏光の光ビ−ムは、λ／４板３により円偏光にされた
後、顕微鏡対物レンズと同等に作用するレンズ４によっ
て発散光に変換されて、被検物１に照射される。ここ
に、レンズ４により被検物１を透過した光束を常に光軸
に対して平行にするための照射光学系５が構成されてい
る。このレンズ４はベース６に搭載されており、レンズ
４と被検物１との間隔を調整することを目的に、ステッ
ピングモータ(図示せず)の回転により光線の進行方向に
進退可能である。ここに、照射光学系５に対する移動手
段が構成され、また、そのステッピングモータには回転
原点位置センサ（図示せず）が取り付けられており、ス
テッピングモータのパルス数を計数することによりレン
ズ４の移動位置の検知が可能とされている（実際には、
後述するパソコン中でのパルス数の計数動作に基づきレ
ンズ４の位置が検知される…検知手段）。レンズ４と被
検物１との間隔は、レンズ４の焦点と被検物（被検レン
ズ）４の焦点がほぼ一致するよう設定されており、それ
により被検物を透過した光は、光学系光軸に対してほぼ
平行な光束となる。It will be described with reference to implementation in the form of the embodiment of the present invention in the drawings. FIG. 1 shows a configuration example of a birefringence measuring device used in the present embodiment. For example, an object 1 to be measured such as a plastic axially symmetric lens is held by a holder (not shown) as a holding means. Retained. A linearly polarized light beam from a semiconductor laser 2 as a light source is circularly polarized by a λ / 4 plate 3 for such an object 1 and then acts as a microscope objective lens. It is converted into divergent light by 4 and is irradiated onto the test object 1. An irradiation optical system 5 for always making the light flux transmitted through the test object 1 by the lens 4 parallel to the optical axis is configured here. The lens 4 is mounted on the base 6 and can be moved back and forth in the traveling direction of the light beam by rotating a stepping motor (not shown) for the purpose of adjusting the distance between the lens 4 and the object 1. Here, moving means for the irradiation optical system 5 is configured, and a rotation origin position sensor (not shown) is attached to the stepping motor, and the lens 4 is moved by counting the number of pulses of the stepping motor. It is possible to detect the position (actually,
The position of the lens 4 is detected based on the counting operation of the number of pulses in a personal computer which will be described later (detection means). The distance between the lens 4 and the inspection object 1 is set so that the focal point of the lens 4 and the focal point of the inspection object (inspection lens) 4 are substantially coincident with each other. The light flux is almost parallel to the optical axis of the system.
【００３４】被検物１を透過し、被検物１の複屈折にて
楕円偏光になった光束を検光子７、レンズ８を介して受
光手段としての受光素子アレイを構成するＣＣＤカメラ
９にて受光する。検光子７に対しては、ほぼ光の進行方
向回りに回転させるステッピングモータ１０及びギヤ系
１１が回転手段１２として設けられている。ステッピン
グモータ１０には回転原点位置センサ（図示せず）が取
り付けられており、ステッピングモータ１０のパルス数
を計数することにより検光子７の回転角度の検知が可能
とされている（実際には、後述するパソコン中でのパル
ス数の計数動作に基づき検光子７の回転角度が検知され
る…回転角検知手段）。１３はこのステッピングモータ
１０を駆動するモータドライバであり、パソコン１４及
びパルス発生器１５からのパルスを受けてステッピング
モータ１０を駆動する。A light beam which has passed through the object to be inspected 1 and has been elliptically polarized by the birefringence of the object to be inspected 1 is passed through an analyzer 7 and a lens 8 to a CCD camera 9 which constitutes a light receiving element array as a light receiving means. To receive light. The analyzer 7 is provided with a stepping motor 10 and a gear system 11 that rotate about the traveling direction of light as a rotating unit 12. A rotation origin position sensor (not shown) is attached to the stepping motor 10, and the rotation angle of the analyzer 7 can be detected by counting the number of pulses of the stepping motor 10 (actually, The rotation angle of the analyzer 7 is detected based on the counting operation of the number of pulses in a personal computer which will be described later (rotation angle detection means). A motor driver 13 drives the stepping motor 10, and receives the pulses from the personal computer 14 and the pulse generator 15 to drive the stepping motor 10.
【００３５】レンズ８は被検物１の表面近傍とＣＣＤカ
メラ９との間でほぼ結像関係が成立するようその位置が
調整されており、その材質には内部の複屈折が十分除去
されたものが用いられている。ここに、レンズ８により
被検物１を透過した光束をＣＣＤカメラ９の受光面上に
結像させるための結像光学系１６が構成されている。１
７は被検物１の透過光の偏光状態を移相させるための移
相子としてのλ／４板であり、ベース１８に搭載されて
いる。このベース１８は図示しないシリンダ等よりなる
移相子進退切換手段により光学系光軸とほぼ垂直な方向
に進退することにより、照射光が被検物１を透過してか
らＣＣＤカメラ９に到達するまでの光路内に対して抜き
差し自在とされている。これにより、被検物１の透過光
の偏光に対して、λ／4の位相差を与える状態と与えな
い状態の両方を生成することが可能とされている。The position of the lens 8 is adjusted so that a substantially image-forming relationship is established between the surface of the object 1 to be examined and the CCD camera 9, and its material is sufficiently free from internal birefringence. Things are used. An image forming optical system 16 for forming an image on the light receiving surface of the CCD camera 9 by the lens 8 is formed here. 1
Reference numeral 7 denotes a λ / 4 plate as a phase shifter for shifting the polarization state of the transmitted light of the test object 1, which is mounted on the base 18. This base 18 advances and retreats in a direction substantially perpendicular to the optical axis of the optical system by a phase shifter advance / retreat switching means including a cylinder (not shown), so that the irradiation light reaches the CCD camera 9 after passing through the object 1. It can be freely inserted into and removed from the optical path up to. As a result, it is possible to generate both the state in which the phase difference of λ / 4 is applied and the state in which the phase difference of λ / 4 is not applied to the polarization of the transmitted light of the DUT 1.
【００３６】また、ＣＣＤカメラ９により撮像された２
次元画像データは、画像入力器１９を通してパソコン１
４のメモリ中に取り込まれ、画像データ及びステッピン
グモータ１０の回転角度データを基に、所定の演算方法
によって被検物１の複屈折位相差及び主軸方位が計算さ
れる。このパソコン１４中に含まれるＣＰＵを始めとす
る演算処理機能により被検レンズ１の複屈折を算出する
演算手段としての機能が実行される。ちなみに、ＣＣＤ
カメラ９により撮像された画像はパソコン１４のモニタ
或いは専用のモニタに表示される。2 taken by the CCD camera 9
Dimensional image data is sent to the personal computer 1 through the image input device 19.
4, the birefringence phase difference and the principal axis direction of the object 1 are calculated by a predetermined calculation method based on the image data and the rotation angle data of the stepping motor 10. A function as an arithmetic means for calculating the birefringence of the lens 1 to be inspected is executed by an arithmetic processing function including a CPU included in the personal computer 14. By the way, CCD
The image captured by the camera 9 is displayed on the monitor of the personal computer 14 or a dedicated monitor.
【００３７】また、レンズ８とＣＣＤカメラ９とを一体
に搭載した受光ベース２０が設けられている。この受光
ベース２０は、図示しないステッピングモータの回転に
より、レンズ８とＣＣＤカメラ９との位置関係を保つこ
とを目的に、光学系の光軸方向に進退自在とされてい
る。さらに、検光子７、レンズ８、ＣＣＤカメラ９、ス
テッピングモータ１０、λ／４板１７、ベース１８、受
光ベース２０を一体に搭載した共通なベース２１が設け
られている。このベース２１はガイド２２により測定光
学系の光軸に対してほぼ直交する方向（図面上、矢印で
示す上下方向）に移動自在とされている。また、このベ
ース２１は空間的な分割測定を実施することを目的に、
ステッピングモータ２３の回転により光学系光軸とほぼ
垂直な方向に進退する。ここに、ガイド２２やステッピ
ングモータ２３等によりベース２１を光軸に直交する方
向に移動調整するベース移動手段２４が構成されてい
る。このベース移動手段２４に対してはそのベース２１
の移動位置を検知するベース位置検知手段（図示せず）
が付加されている。Further, a light receiving base 20 on which the lens 8 and the CCD camera 9 are mounted integrally is provided. The light receiving base 20 is movable in the optical axis direction of the optical system for the purpose of maintaining the positional relationship between the lens 8 and the CCD camera 9 by the rotation of a stepping motor (not shown). Further, a common base 21 on which an analyzer 7, a lens 8, a CCD camera 9, a stepping motor 10, a λ / 4 plate 17, a base 18 and a light receiving base 20 are integrally mounted is provided. The base 21 is movable by a guide 22 in a direction substantially perpendicular to the optical axis of the measurement optical system (vertical direction indicated by an arrow in the drawing). In addition, this base 21 is for the purpose of performing spatially divided measurement,
Rotation of the stepping motor 23 advances and retracts in a direction substantially perpendicular to the optical axis of the optical system. Here, a base moving means 24 for moving and adjusting the base 21 in a direction orthogonal to the optical axis by a guide 22, a stepping motor 23, etc. is configured. For this base moving means 24, its base 21
Base position detecting means (not shown) for detecting the moving position of the
Has been added.
【００３８】このような複屈折測定装置を用いた本実施
の形態の複屈折測定方法について説明する。まず、被検
物１をホルダにより所定の位置にセットし、ベース１８
を後退させて、被検物１からＣＣＤカメラ９までの光路
内にλ／４板１７が介在されない状態、即ち、被検物透
過光の偏光に対しλ／4の位相差を与えない状態にす
る。この状態で、検光子７の透過軸方位を回転原点から
（１８０／ｎ）度ずつ回転させる。ｎは予め設定された
測定ポイント数である。検光子７が（１８０／ｎ）度回
転する毎にＣＣＤ画像をパソコン１４のメモリに取り込
んで、検光子７の回転角度デ−タとｎ枚のＣＣＤ画像デ
−タを取得する。A birefringence measuring method of this embodiment using such a birefringence measuring apparatus will be described. First, the object to be inspected 1 is set at a predetermined position by the holder, and the base 18
To a state where the λ / 4 plate 17 is not interposed in the optical path from the DUT 1 to the CCD camera 9, that is, a state in which the λ / 4 phase difference is not given to the polarization of the transmitted light of the DUT. To do. In this state, the transmission axis direction of the analyzer 7 is rotated by (180 / n) degrees from the rotation origin. n is the preset number of measurement points. Every time the analyzer 7 rotates by (180 / n) degrees, the CCD image is taken into the memory of the personal computer 14, and the rotation angle data of the analyzer 7 and n CCD image data are acquired.
【００３９】次に、ベース１８を前進させ、被検物１か
らＣＣＤカメラ９までの光路内にλ／４板１７を介在さ
せて、被検物１の透過偏光にほぼλ／4の位相差を与え
る。この場合、被検物１を透過して、光学系光軸に対し
て平行になった光束がλ／4板１７の面にほぼ垂直に入
射するように、λ／4板１７及びベース１８を位置調整
しておく。ベース１８を前進させた状態で、前述した場
合と同様、検光子７の透過軸方位を回転原点から（１８
０／ｎ）度ずつ回転させながら、ＣＣＤ画像デ−タをパ
ソコン１４のメモリに取り込んで、検光子７の回転角度
デ−タとｎ枚の画像デ−タを取得する。Next, the base 18 is moved forward, the λ / 4 plate 17 is interposed in the optical path from the DUT 1 to the CCD camera 9, and the transmitted polarized light of the DUT 1 has a phase difference of approximately λ / 4. give. In this case, the λ / 4 plate 17 and the base 18 are arranged so that the light flux that has passed through the DUT 1 and becomes parallel to the optical axis of the optical system enters the surface of the λ / 4 plate 17 substantially vertically. Adjust the position. With the base 18 moved forward, as in the case described above, the transmission axis direction of the analyzer 7 is set to (18
The CCD image data is loaded into the memory of the personal computer 14 while being rotated by 0 / n) degrees, and the rotation angle data of the analyzer 7 and n image data are acquired.
【００４０】以上の手順により取得した合計２×ｎ枚の
画像デ−タと検光子７の回転角のデ−タを基に、以下の
演算処理にて被検物１の複屈折を求める。The birefringence of the test object 1 is obtained by the following arithmetic processing based on a total of 2.times.n pieces of image data obtained by the above procedure and the rotation angle data of the analyzer 7.
【００４１】まず、ベース１８が後退した状態におい
て、検光子７の透過軸方位を回転させたとき、ＣＣＤカ
メラ９の各画素により検出される光強度Ｉ０ は(１)式
Ｉ０ ＝（１／２）(１−sinδsin２φcos２θ＋cosδsin２θ） ……（１）
で表される。また、ベース１８が前進した状態におい
て、検光子７の透過軸方位を回転させたとき、ＣＣＤカ
メラ９の各画素により検出される光強度Ｉ４５ は(２)
式
Ｉ４５＝（１／２）(１＋cosδcos２θ−sinδcos２φsin２θ） ……（２）
で表される。これらの（１）(２)式において、θは検光
子７の透過軸方位、δは被検物１の複屈折位相差、φは
被検物１の主軸方位である。First, when the transmission axis azimuth of the analyzer 7 is rotated with the base 18 retracted, the light intensity I 0 detected by each pixel of the CCD camera 9 is expressed by the formula (1) I 0 = (1 / 2) (1-sinδsin2φcos2θ + cosδsin2θ) ... (1) Further, when the transmission axis azimuth of the analyzer 7 is rotated with the base 18 moved forward, the light intensity I 45 detected by each pixel of the CCD camera 9 is (2)
Formula I 45 = (1/2) (1 + cosδcos2θ-sinδcos2φsin2θ) (2) In these equations (1) and (2), θ is the transmission axis direction of the analyzer 7, δ is the birefringence phase difference of the test object 1, and φ is the main axis direction of the test object 1.
【００４２】ここに、検光子７の回転に伴う光強度変化
の位相を各々ψ０，ψ４５とすると、（１）(２)式よ
り、これらの位相ψ０，ψ４５ は、
ψ０ ＝tan−１（−tan２φ） …………………………………（３）
ψ４５＝tan−１（−１／tanδcos２φ） …………………………（４）
のように表される。Here, assuming that the phases of the light intensity change due to the rotation of the analyzer 7 are ψ 0 and ψ 45 , respectively, from the expressions (1) and (2), these phases ψ 0 and ψ 45 are ψ 0 = tan −1 (−tan 2φ) ……………………………… (3) ψ 45 = tan −1 (−1 / tan δcos 2φ) ………………………… (4) Represented by.
【００４３】また、取り込んだＣＣＤ画像データと検光
子７の回転角データとにより、ψ０，ψ４５ とは、次
の（５）(６)式
ψ０ ＝tan−１｛Σ(Ｉ０ｉ・sin２θｉ）／Σ(Ｉ０ｉ
・cos２θｉ）} …（５）
ψ４５＝tan−１｛Σ(Ｉ４５ｉ・sin２θｉ）／Σ(Ｉ
４５ｉ・cos２θｉ）}…（６）
で計算される。Further, based on the captured CCD image data and the rotation angle data of the analyzer 7, ψ 0 and ψ 45 are expressed by the following formulas (5) and (6) ψ 0 = tan −1 {Σ (I 0i · sin2θ i ) / Σ (I 0i
-Cos2 (theta) i )} ... (5) (psi) 45 = tan- 1 {(( 45i * sin2 (theta) i ) / ((I
45i · cos2θ i )} (6).
【００４４】従って、これらの（３）〜（６）式より、 δ＝tan−１（cosφ／tanψ４５） …………………（７） φ＝（１／２）tan−１（１／tanψ０） …………………（８） により、位相差δ、主軸方位φが求められる。Therefore, from these equations (3) to (6), δ = tan −1 (cosφ / tanφ 45 ) ... (7) φ = (1/2) tan −1 (1 / Tan ψ 0 ) …………………………………………………………………………………………………………………… (8)
【００４５】ところで、図１に示したような測定光学系
では、被検物１に照射した光は、被検物１によりほぼ平
行化されるため、被検物１を透過した光は、光学系光軸
と垂直な平面内で被検物１とほぼ同じ面積をもつ平行光
束となる。ここに、被検物１が書込み光学系に用いられ
るようなレンズの場合、通常その面積は大きいため、透
過光束もそれに伴い大きな面積となる。被検物１の透過
光束がλ／4板１７を透過することを考えた場合、λ／4
板１７の面積は直径３０ｍｍ程度が上限で、それを超え
るサイズのものを作ろうとするとコストがかかるため、
被検物透過光束の全体について、λ／4板１７を透過さ
せることができない。かといって、被検物１の透過光束
をλ／4板１７の面積に合わせて光学的に縮小しても、
書込み光学系に用いられるレンズの場合、その主走査方
向の長さに対して副走査方向は大幅に短いため、副走査
方向における測定の空間的な分解能が低下する。By the way, in the measuring optical system as shown in FIG. 1, the light radiated to the object 1 to be inspected is almost parallelized by the object 1 to be inspected. It becomes a parallel light flux having substantially the same area as the DUT 1 in a plane perpendicular to the optical axis of the system. Here, in the case where the DUT 1 is a lens used in a writing optical system, its area is usually large, and therefore the transmitted light flux also has a large area accordingly. Considering that the transmitted light flux of the object to be inspected 1 passes through the λ / 4 plate 17, λ / 4
The upper limit of the area of the plate 17 is about 30 mm, and it will be costly to make a size larger than that.
The λ / 4 plate 17 cannot be transmitted with respect to the entire test object transmitted light flux. However, even if the transmitted light flux of the DUT 1 is optically reduced according to the area of the λ / 4 plate 17,
In the case of a lens used in a writing optical system, the sub-scanning direction is significantly shorter than the length in the main-scanning direction, so that the spatial resolution of measurement in the sub-scanning direction deteriorates.
【００４６】このため、本実施の形態では、請求項３記
載の発明に相当する空間分割測定方法として、λ／４板
１７以降の光学系素子をユニットとしてベース２１に一
体にして、このベース２１を光学系光軸にほぼ直交する
方向に移動させ、被検物１とほぼ同じサイズを持つ光弾
性干渉縞の空間像を部分的に幾つかに分割してＣＣＤカ
メラ９で観察することで、測定を行うものである。例え
ば、図２に示すように、まず、被検物１の測定対象領域
Ｅ１が観察できるようにステッピングモータ２３により
ベース２１を移動させ、この状態で上述のように位相差
及び主軸方位を測定する。続いて、被検物１の測定対象
領域Ｅ２が観察できるようにステッピングモータ２３に
よりベース２１を移動させ、この状態で同様に位相差及
び主軸方位を測定し、さらに、被検物１の測定対象領域
Ｅ３が観察できるようにステッピングモータ２３により
ベース２１を移動させ、この状態で同様に位相差及び主
軸方位を測定すればよい。Ｅ１〜Ｅ３の領域での測定結
果をつなぎ合わせることで、被検物１全体における測定
結果が得られる。被検物１が高さ方向に大きい場合で
も、高さ方向に移動可能なステージを用意すれば同様の
分割測定が可能となる。Therefore, in this embodiment, as a space division measuring method corresponding to the invention of claim 3, the optical system elements after the λ / 4 plate 17 are integrated as a unit with the base 21, and the base 21 is integrated. Is moved in a direction substantially orthogonal to the optical axis of the optical system, and the aerial image of the photoelastic interference fringes having substantially the same size as the DUT 1 is partially divided and observed by the CCD camera 9. It is to measure. For example, as shown in FIG. 2, first, the base 21 is moved by the stepping motor 23 so that the measurement target region E1 of the test object 1 can be observed, and in this state, the phase difference and the main axis azimuth are measured as described above. . Subsequently, the base 21 is moved by the stepping motor 23 so that the measurement target region E2 of the test object 1 can be observed, and the phase difference and the main axis azimuth are similarly measured in this state, and the measurement target of the test object 1 is further measured. The base 21 is moved by the stepping motor 23 so that the region E3 can be observed, and in this state, the phase difference and the main axis azimuth may be similarly measured. By connecting the measurement results in the areas E1 to E3, the measurement result of the entire test object 1 can be obtained. Even when the DUT 1 is large in the height direction, the same divisional measurement can be performed by preparing a stage that can move in the height direction.
【００４７】なお、被検物１の測定対象領域を決定する
際は、例えば、ベース２１を移動させながら、ＣＣＤカ
メラ９で撮像しモニタした光弾性干渉縞を観察すること
で、適当な領域を選択するようにしてもよい。或いは、
ステッピングモータ２３に回転原点位置センサを取り付
け、このステッピングモータ２３に供給するパルス数に
よりベース２１の移動距離を検知できる構成とし、予め
測定対象領域を決定しておき、その領域を観察できる位
置までベース２１を自動的に移動させるようにしてもよ
い。後者の場合、実際にはパソコン１４中でのパルス数
の計数動作に基づきベース２１（従って、λ／４板１７
等）の移動距離が検知される（ベース位置検知手段）。When determining the measurement target area of the test object 1, for example, by observing the photoelastic interference fringes imaged and monitored by the CCD camera 9 while moving the base 21, an appropriate area can be determined. You may make it select. Alternatively,
A rotation origin position sensor is attached to the stepping motor 23, and the moving distance of the base 21 can be detected by the number of pulses supplied to the stepping motor 23. The measurement target area is determined in advance, and the base is moved to a position where the area can be observed. 21 may be moved automatically. In the latter case, the base 21 (therefore, the λ / 4 plate 17) is actually based on the counting operation of the pulse number in the personal computer 14.
Etc.) is detected (base position detecting means).
【００４８】このようにして、本実施の形態の基本的構
成及び動作によれば、分解能を低下させることなく、被
検物１全体の複屈折測定が可能となる。As described above, according to the basic configuration and operation of the present embodiment, it is possible to measure the birefringence of the entire object 1 without lowering the resolution.
【００４９】つづいて、本実施の形態の第一の変形例を
図１及び図２を参照して説明する。 Next, a first modified example of the present embodiment will be described with reference to FIGS .
【００５０】図２で説明したような空間分割測定を実施
する場合、被検物１の表面に凹凸（奥行き）があると、
受光ベース２０を移動させたときに被検物面とＣＣＤカ
メラ９の受光面との結像関係がくずれる。例えば、被検
物１がレンズのとき、測定装置にセットしたレンズの光
軸付近（頂点付近）の表面とＣＣＤカメラ９の受光面と
の結像関係を成立させた（ピントを合わせた）状態にお
いて、ベース２１を光学系光軸と垂直な方向に移動させ
てレンズ(被検物１)の端面部分を観察したとき、レンズ
は曲率をもっているため、被検レンズの表面とＣＣＤカ
メラ９の受光素子面との結像関係が成り立たなくなる。
従って、光学的にぼけた像が得られることになり、その
ような像を用いて測定を実施すると測定結果にノイズが
含まれる。When performing the space division measurement as described with reference to FIG. 2, if the surface of the object to be inspected 1 has unevenness (depth),
When the light receiving base 20 is moved, the image forming relationship between the surface of the object to be inspected and the light receiving surface of the CCD camera 9 is broken. For example, when the DUT 1 is a lens, a state is established (focused) between the surface near the optical axis (near the apex) of the lens set in the measuring device and the light receiving surface of the CCD camera 9. When the base 21 is moved in the direction perpendicular to the optical axis of the optical system and the end surface of the lens (test object 1) is observed, since the lens has a curvature, the surface of the test lens and the light received by the CCD camera 9 are received. The imaging relationship with the element surface is no longer established.
Therefore, an optically blurred image is obtained, and when the measurement is performed using such an image, the measurement result contains noise.
【００５１】そこで、本変形例では、被検物１の形状情
報（被検物表面の凹凸情報）を予め測定装置に記憶させ
ておき、ベース２１の光学系光軸と垂直な方向への移動
量に合わせて、受光ベース２０を光学系光軸方向に移動
させつつ測定を実施する。レンズ８とＣＣＤカメラ９と
の間隔が常に一定で受光ベース２０を移動させるため、
結像光学系の結像倍率は受光ベース２０の移動によらず
常に一定に保たれる。例えば、被検物１が凸レンズの場
合は、その光軸付近の被検物１表面に対して、端面部分
の表面は、ＣＣＤカメラ９からみて奥に存在することに
なる。その場合、被検レンズの曲率半径をＲ、結像光学
系にて観察する領域の光学系光軸からの距離（レンズ高
さ）をｈ、被検レンズの光軸付近の表面と観察領域にお
ける表面との奥行きの差をｄとすると、ｄは次の(９)式
ｄ＝Ｒ−√（Ｒ２−ｈ２） …………………………(９)
で表せる。Therefore, in the present modification , the shape information of the object 1 to be inspected (information on the surface roughness of the object to be inspected) is stored in the measuring device in advance, and the base 21 is moved in the direction perpendicular to the optical axis of the optical system. The measurement is performed while moving the light receiving base 20 in the optical axis direction of the optical system according to the amount. Since the distance between the lens 8 and the CCD camera 9 is always constant and the light receiving base 20 is moved,
The imaging magnification of the imaging optical system is always kept constant regardless of the movement of the light receiving base 20. For example, when the object 1 to be inspected is a convex lens, the surface of the end face portion is behind the surface of the object 1 to be inspected near the optical axis thereof when viewed from the CCD camera 9. In that case, the radius of curvature of the lens to be inspected is R, the distance (lens height) from the optical system optical axis of the region to be observed by the imaging optical system is h, and the surface near the optical axis of the lens to be inspected and the observation region are Assuming that the difference in depth from the surface is d, d can be expressed by the following equation (9) d = R-√ (R 2 -h 2 ) ... (9).
【００５２】従って、被検物１の光軸付近を測定した状
態からベース２１を光学系光軸からｈだけ移動させたと
きは、受光ベース２０をｄだけ光学系光軸方向に前進さ
せて測定を実施すれば、測定する領域における被検物１
の表面にピントのあった鮮明な画像が得られ、正確な測
定が可能となる。Therefore, when the base 21 is moved by h from the optical axis of the optical system while the vicinity of the optical axis of the object to be inspected 1 is measured, the light receiving base 20 is moved forward by d in the optical system optical axis direction for measurement. If you perform the
A clear image with the surface of the object in focus can be obtained, and accurate measurement is possible.
【００５３】本実施の形態の第二の変形例を図１ないし
図３を参照して説明する。上述した説明では、被検物１
が軸対称でかつ、焦点距離が短いレンズである場合であ
るが、本変形例では、被検物１が非軸対称なレンズの場
合に関する。A second modification of the present embodiment will be described with reference to FIGS. 1 to 3. In the above description, the inspection object 1
Is a lens that is axisymmetric and has a short focal length, but in this modification , the object 1 is a non-axisymmetric lens.
【００５４】書込み光学系に用いられるレンズにおいて
は、直交２方向（主走査方向と副走査方向）で焦点距離
が異なるような非軸対称のレンズが用いられることがあ
る。このようなレンズの複屈折を測定する場合、被検物
１に球面波を照射したのでは被検物の透過光束を光学系
光軸に対して平行化できない。この結果、被検物１を透
過した光線はλ／4板１７の面に斜めに入射することに
なり、λ／4板１７を透過した光の偏光にλ／４の位相
差を正確に与えることができなくなり、そのための測定
誤差が生じる。また、被検物１の主走査方向と副走査方
向で結像の仕方が異なってくるため、ＣＣＤカメラ９の
受光面上では歪んだ画像が得られ、被検物１の全面に渡
って正確な測定が困難になる。As the lens used in the writing optical system, a non-axisymmetric lens having different focal lengths in two orthogonal directions (main scanning direction and sub scanning direction) may be used. When measuring the birefringence of such a lens, the transmitted light flux of the test object cannot be made parallel to the optical axis of the optical system by irradiating the test object 1 with a spherical wave. As a result, the light rays that have passed through the DUT 1 are obliquely incident on the surface of the λ / 4 plate 17, and the polarization of the light that has passed through the λ / 4 plate 17 is accurately given a λ / 4 phase difference. Cannot be performed, which causes a measurement error. In addition, since the image forming method differs between the main scanning direction and the sub-scanning direction of the test object 1, a distorted image is obtained on the light receiving surface of the CCD camera 9, and the entire test object 1 is accurately measured. Measurement becomes difficult.
【００５５】そこで、本変形例では、このような非軸対
称レンズを被検物１として測定する場合は、被検物１に
軸対称な光束を照射せずに、例えば、シリンダレンズの
ように一方向にのみ曲率をもつレンズを、図１における
レンズ４と非軸対称レンズ（被検物１）との間に設置し
て、非軸対称な光束を被検物１に照射してやることで、
被検物１の透過光束を平行化させるようにしたものであ
る。Therefore, in the present modification , when such a non-axisymmetric lens is measured as the test object 1, the test object 1 is not irradiated with an axially symmetric light beam, and, for example, a cylinder lens is used. By installing a lens having a curvature only in one direction between the lens 4 and the non-axisymmetric lens (inspection object 1) in FIG. 1, and irradiating the inspected object 1 with a non-axisymmetric light flux,
The transmitted light flux of the inspection object 1 is made parallel.
【００５６】例えば、図３に示すように、非軸対称レン
ズ（被検物１）の主走査方向の焦点距離をｆ1、副走査
方向の焦点距離をｆ2（ただし、ｆ1＞ｆ2）、レンズ４
の焦点距離をｆo、図１におけるレンズ４と非軸対称レ
ンズ（被検物１）との間に設置したシリンダレンズ２５
の副走査方向の焦点距離をｆc（主走査方向は平面なの
で、その焦点距離は無限大）、肉厚をｔ、屈折率をｎc
とし、レンズ４と非軸対称レンズ（被検物１）との間隔
（主点間距離）をΔ1、シリンダレンズ２５と非軸対称
レンズ（被検物１）との間隔をΔ2としたとき、
Δ１ ＝ｆ０＋ｆ１−ｔ{１−(１／ｎｃ)} ……………………(10)
ｆ１−ｔ{１−(１／ｎｃ)}＝{ｆｃ(Δ２−ｆ２)／(Δ２−ｆ２−ｆ２})＋Δ２
……………………(11)
を満たすように間隔Δ1、Δ2を設定すると、非軸対称レ
ンズ（被検物１）を透過した光をほぼ平行化できる。こ
れにより、前述した実施の形態の方法による測定が可能
となる。また、各々のレンズをステージ等の駆動手段に
搭載して、形状データを測定装置に記憶しておけば、光
学系配置の自動設定も可能である。For example, as shown in FIG. 3, the focal length of the non-axisymmetric lens (test object 1) in the main scanning direction is f 1 , and the focal length in the sub scanning direction is f 2 (where f 1 > f 2 ), Lens 4
The focal length of which is f o , and the cylinder lens 25 installed between the lens 4 and the non-axisymmetric lens (test object 1) in FIG.
In the sub-scanning direction is f c (since the main scanning direction is a plane, the focal length is infinite), the wall thickness is t, and the refractive index is n c.
The distance between the lens 4 and the non-axisymmetric lens (test object 1) (distance between principal points) is Δ 1 , and the distance between the cylinder lens 25 and the non-axisymmetric lens (test object 1) is Δ 2 . Then, Δ 1 = f 0 + f 1 −t {1- (1 / n c )} …………………… (10) f 1 −t {1- (1 / n c )} = {f c (Δ 2 -f 2) / ( Δ 2 -f 2 -f 2}) + Δ 2 ........................ interval delta 1 so as to satisfy (11), setting the delta 2, non-axisymmetric lens The light transmitted through the (test object 1) can be substantially collimated. This enables the measurement by the method of the above-described embodiment. Further, if each lens is mounted on a driving means such as a stage and the shape data is stored in the measuring device, the optical system arrangement can be automatically set.
【００５７】本実施の形態の第三の変形例を図１及び図
２を参照して説明する。本変形例は、被検物１が平行平
板或いは焦点距離の長いレンズの場合への適用例であ
る。A third modification of the present embodiment will be described with reference to FIGS. 1 and 2. This modification is an example of application to the case where the test object 1 is a parallel plate or a lens having a long focal length.
【００５８】被検物１が平行平板のときは、被検物１に
球面波を照射しても被検物１の透過光束は平行化されな
いため、予め平行化した光束を被検物１に照射する。具
体的には、図１におけるレンズ４と被検物１との間の光
軸上に軸対称レンズを配設して、この軸対称レンズの焦
点とレンズ４の焦点とを一致させてやることで、平行光
束を被検物に照射してやることができ、前述した方法に
よる測定が可能となる。この場合、レンズ４と被検物１
の間に配設される軸対称レンズを光学系光軸方向に進退
可能なステージに搭載し、被検物１の形状データを測定
装置に記憶しておけば、光学系配置の自動設定が可能で
ある。When the object to be inspected 1 is a parallel plate, the transmitted light flux of the object to be inspected 1 is not parallelized even if the object to be inspected 1 is irradiated with a spherical wave. Irradiate. Specifically, an axially symmetric lens is provided on the optical axis between the lens 4 and the object 1 in FIG. 1, and the focal point of this axially symmetric lens and the focal point of the lens 4 are made to coincide with each other. in, can'll irradiating the collimated beam into the test object, it is possible to measure by how the aforementioned. In this case, the lens 4 and the test object 1
If the axially symmetric lens arranged between the two is mounted on a stage that can move back and forth in the optical axis direction of the optical system, and the shape data of the DUT 1 is stored in the measuring device, the optical system layout can be set automatically. Is.
【００５９】また、被検物１が焦点距離の長いレンズの
場合、図１におけるレンズ４の焦点と被検物１の焦点と
を一致させるには、レンズ４と被検物１との間隔を大き
くする必要があり、測定装置が巨大化する。そのため、
本変形例では、被検物１が焦点距離の長いレンズの場合
は、それを平行平板と見倣して、平行平板測定のときと
同様に平行光束を被検物１に照射して測定を実施する。
実際には、平行平板でないので、その透過光束は厳密に
は平行されず、そのための測定誤差が生じるが、焦点距
離の長いレンズの場合、その誤差は非常に小さくなるた
め無視できる。それにより測定装置の巨大化が防げる。Further, when the object 1 to be inspected is a lens having a long focal length, in order to make the focal point of the lens 4 in FIG. It needs to be large, and the measuring device becomes huge. for that reason,
In this modification , when the DUT 1 is a lens having a long focal length, it is imitated as a parallel plate, and a parallel luminous flux is applied to the DUT 1 in the same manner as in the parallel plate measurement. carry out.
Actually, since it is not a parallel flat plate, the transmitted light flux is not strictly parallel, and a measurement error occurs for that, but in the case of a lens having a long focal length, the error is extremely small and can be ignored. This prevents the measuring device from becoming huge.
【００６０】また、被検物１が平行平板或いは焦点距離
の長いレンズの場合における、空間分割測定について説
明する。被検物１に平行光束を照射する場合は、被検物
１の全面を覆えるだけの直径の光束を照射しないと、前
述したような、図１におけるベース２１を光学系光軸と
ほぼ垂直な方向に移動させながらの空間分割測定が実施
できない。被検物１の面積が大きい場合、被検物１の全
面を覆える光束を作ろうとすると高価な光学系が必要と
なる。[0060] Also, some have test object 1 is a parallel plate is in the case of the long lens focal length, is described space division measurement. When irradiating the collimated beam into the specimen 1 when not irradiated with light flux diameter of only Ooeru the whole surface of the test object 1, as described above, almost an optical system optical axis base 21 in FIG. 1 Space division measurement cannot be performed while moving in the vertical direction. When the area of the object to be inspected 1 is large, an expensive optical system is required to create a light beam that covers the entire surface of the object to be inspected 1.
【００６１】この問題を解決するために、被検物１およ
びそのホルダ（保持手段）を光学系光軸と垂直な方向に
移動可能なステージ（保持手段移動手段）に搭載し、ス
テージを光学系光軸とほぼ垂直な方向に移動させその位
置を保持手段位置検知手段により検知しながら空間分割
測定を実施する。この際、ベース２１側を固定したまま
で、また、被検物１表面は平面とみなせるので受光ベー
ス２０は移動させなくてよい。In order to solve this problem, the object to be inspected 1 and its holder (holding means) are mounted on a stage (holding means moving means) which is movable in a direction perpendicular to the optical axis of the optical system, and the stage is used as an optical system. Space division measurement is carried out while moving in a direction substantially perpendicular to the optical axis and detecting the position thereof by the holding means position detection means. At this time, the light receiving base 20 does not have to be moved since the surface of the DUT 1 can be regarded as a flat surface while the base 21 side is fixed.
【００６２】被検物１が非球面レンズである場合も、上
述の何れかの装置及び方法によっても被検レンズ透過光
束を厳密には平行化できないが、そのための誤差は通常
小さく無視できるため、球面レンズ、或いは平行平板と
見倣して上述の方法を適用してもよい。Even when the object 1 to be inspected is an aspherical lens, the light flux transmitted through the lens to be inspected cannot be strictly collimated by any of the above-mentioned devices and methods, but the error for that is usually small and can be ignored. The above-mentioned method may be applied by imitating a spherical lens or a parallel plate.
【００６３】本実施の形態の第四の変形例を図１及び図
４を参照して説明する。 A fourth modification of the present embodiment will be described with reference to FIGS. 1 and 4 .
【００６４】本実施の形態の測定方法による複屈折位相
差の測定結果の出力範囲は−λ／4〜＋λ／4（λ：測定
に使用する半導体レーザ２の波長）の範囲に限定され、
それを越えるような大きな複屈折の位相差測定結果に
は、光源波長に起因する不確定性が含まれる。即ち、複
屈折位相差の真値をΔ、測定値をδとすると、両者には
次式
Δ＝δ±ｎ・λ（ｎ：整数） ……………………(12)
の関係が成り立ち、整数ｎの値が特定できない。The output range of the birefringence phase difference measurement result by the measuring method of the present embodiment is limited to the range of −λ / 4 to + λ / 4 (λ: wavelength of the semiconductor laser 2 used for measurement).
The phase difference measurement result of a large birefringence exceeding that includes an uncertainty due to the wavelength of the light source. That is, assuming that the true value of the birefringence phase difference is Δ and the measured value is δ, the relationship of the following equation Δ = δ ± n · λ (n: integer) …………………… (12) Therefore, the value of the integer n cannot be specified.
【００６５】そこで、本変形例では、ＣＣＤカメラ９の
隣接画素（隣接受光素子）における位相差測定結果につ
いて、その差を検出し、差を補正する処理を施すことに
より、光源波長に制限を受けない広い測定レンジが得ら
れるようにしたものである。Therefore, in this modification , the light source wavelength is limited by detecting the difference between the phase difference measurement results of the adjacent pixels (adjacent light receiving elements) of the CCD camera 9 and correcting the difference. It is designed to obtain a wide measurement range.
【００６６】まず、図４(ａ)に、位相差測定結果の断面
分布の例を示すが、測定結果は−λ／4〜＋λ／4の範囲
内に限られている。図４(ａ)における横軸はＣＣＤカメ
ラ９の位置を表わしている。ここで、ＣＣＤカメラ９に
おける隣り合う画素間で測定値の差をとると、測定レン
ジを越える位置でλ／2に近い段差が検出される。従っ
て、その位置で段差を補正するように測定値にλ／2を
足すか、あるいは引くことで、図４(ａ)の断面分布が図
４(ｂ)のように変換でき、光源波長の制限を受けない広
いレンジで測定結果が得られることになる。First, FIG. 4A shows an example of the cross-sectional distribution of the phase difference measurement result, but the measurement result is limited to the range of -λ / 4 to + λ / 4. The horizontal axis in FIG. 4A represents the position of the CCD camera 9. Here, when the difference between the measured values between the adjacent pixels in the CCD camera 9 is taken, a step close to λ / 2 is detected at a position exceeding the measurement range. Therefore, by adding or subtracting λ / 2 to the measured value so as to correct the step at that position, the cross-sectional distribution of FIG. 4 (a) can be converted as shown in FIG. 4 (b), and the light source wavelength limitation The measurement result can be obtained in a wide range that is not affected by.
【００６７】本実施の形態の第五の変形例を図１を参照
して説明する。 A fifth modification of the present embodiment will be described with reference to FIG .
【００６８】本変形例では、例えば図１の測定装置にお
ける結像光学系１６を複数枚のレンズで構成し、各々の
レンズの間隔を変えて合成焦点距離を変化させること
で、結像光学系１６の倍率が可変となる。光弾性干渉縞
の縞間隔が狭く、縞間隔がＣＣＤカメラ９の単一画素の
サイズより小さくなった場合、結像光学系１６の倍率を
あげれば、ＣＣＤカメラ９の受光面上での干渉縞間隔が
広がる。それにより干渉縞を検知することができ、上述
した第四の変形例の方法によるＣＣＤカメラ９の隣接画
素間での測定値の比較処理が可能となり、測定レンジを
拡大できる。In this modification, for example , the image forming optical system 16 in the measuring apparatus of FIG. 1 is composed of a plurality of lenses, and the combined focal length is changed by changing the distance between the lenses, thereby forming the image forming optical system. The magnification of 16 is variable. If the fringe spacing of the photoelastic interference fringes is narrow and the fringe spacing is smaller than the size of a single pixel of the CCD camera 9, the interference fringes on the light receiving surface of the CCD camera 9 can be increased by increasing the magnification of the imaging optical system 16. The distance increases. As a result, the interference fringes can be detected, the comparison processing of the measurement values between the adjacent pixels of the CCD camera 9 by the method of the fourth modification described above becomes possible, and the measurement range can be expanded.
【００６９】本実施の形態の第六の変形例を図１及び図
５を参照して説明する。 A sixth modification of the present embodiment will be described with reference to FIGS. 1 and 5 .
【００７０】上述した第四の変形例の方法によると、無
限大の測定レンジが得られるが、被検領域内におけるＣ
ＣＤカメラ９の隣り合う画素の全部を比較、或いは補正
するのには処理に時間がかかる。According to the method of the fourth modified example described above, an infinite measurement range can be obtained, but C in the test area is
It takes a long time to compare or correct all the adjacent pixels of the CD camera 9.
【００７１】そこで、本実施の形態の測定方法による複
屈折位相差の測定レンジ−λ／4〜＋λ／4を、−λ／2
〜＋λ／2まで広げる処理を短時間で行う方法を提供す
るものである。[0071] Therefore, the measurement range -λ / 4~ + λ / 4 birefringence phase difference by the measurement method of the present implementation, 1-? / 2
It is intended to provide a method of performing a process of expanding to + λ / 2 in a short time.
【００７２】図１において被検物１の透過光束がＣＣＤ
カメラ９に到達するまでの光路内にλ／4板１７を介在
させたとき、このλ／4板１７を透過した楕円偏光の長
軸方向を情報として用いる。例えば図５において、αが
λ／4板１７を透過した楕円偏光の長軸方向であるとす
ると、αが第一及び第二象限のときは、位相差測定値に
処理を加えず、第三象限のときは、測定値からλ／2を
引き、第四象限のときは、測定値にλ／2を足すという
処理を施す。それにより、測定レンジ−λ／4〜＋λ／4
を−λ／2〜＋λ／2まで広げることができ、その処理が
短時間で行える。また、上述した第四の変形例の方法で
は、隣接画素間における測定値のλ／2の差を検出しよ
うとするが、測定値にノイズがのっているときは隣接画
素間での測定値の差がλ／2近くまでならないときがあ
り、その場合は処理誤差が生じる。本変形例では、この
ような隣接画素間における測定値の比較処理を行わない
ため、差の検出誤差、補正誤差を完全になくせる。In FIG. 1, the transmitted light flux of the object 1 is a CCD.
When the λ / 4 plate 17 is interposed in the optical path up to the camera 9, the major axis direction of the elliptically polarized light transmitted through the λ / 4 plate 17 is used as information. For example, in FIG. 5, if α is the major axis direction of the elliptically polarized light transmitted through the λ / 4 plate 17, when α is in the first and second quadrants, the phase difference measurement value is not processed, and In the quadrant, λ / 2 is subtracted from the measured value, and in the fourth quadrant, λ / 2 is added to the measured value. As a result, measurement range -λ / 4 to + λ / 4
Can be expanded from -λ / 2 to + λ / 2, and the processing can be performed in a short time. Further, in the method of the fourth modified example described above, the difference of λ / 2 of the measured values between the adjacent pixels is detected, but when the measured values have noise, the measured values between the adjacent pixels are measured. In some cases, the difference between the two does not reach close to λ / 2, in which case a processing error occurs. In this modification , since the comparison process of the measured values between the adjacent pixels is not performed, the difference detection error and the correction error can be completely eliminated.
【００７３】本実施の形態の第七の変形例を図１及び図
５を参照して説明する。本変形例は、第四の変形例と第
六の変形例とを組合せたものである。A seventh modified example of the present embodiment will be described with reference to FIGS. 1 and 5. This modification is the same as the fourth modification and the
This is a combination of the six modified examples .
【００７４】まず、第六の変形例の方法にて−λ／4〜
＋λ／4の測定レンジを−λ／2〜＋λ／2まで拡大して
おき、その後、第四の変形例の方法にて無限大まで測定
レンジを広げる。第一段階における測定レンジの拡大を
処理誤差を完全になくして実現できる上に、第二段階で
隣接画素間において検出する段差の量がλ／2からλま
で広げられ、段差の検出がしやすくなるため、その検出
誤差も低減できる。従って、装置で使用する光源の波長
を越えるような大きな複屈折についても、より精度よく
測定できる。First, according to the method of the sixth modification, -λ / 4-
The measurement range of + λ / 4 is expanded to −λ / 2 to + λ / 2, and then the measurement range is expanded to infinity by the method of the fourth modification . The measurement range can be expanded in the first step without any processing error, and the amount of the level difference detected between adjacent pixels in the second level can be expanded from λ / 2 to λ, making it easy to detect the level difference. Therefore, the detection error can be reduced. Therefore, even large birefringence exceeding the wavelength of the light source used in the apparatus can be measured with higher accuracy.
【００７５】本実施の形態の第八の変形例を図１及び図
６を参照して説明する。本変形例では、２次元被検空間
内の基準と設定する位置にて、複屈折位相差の絶対量を
推定するための構成が付加されている。図６において、
３１は白色光源ユニット、３２は偏光板３３とλ／４板
３４とによる円偏光子、３５は偏光板３６とλ／４板３
７とによる円偏光子である。これにより、被検物１には
円偏光が照射され、被検物１の複屈折がないときには図
の観察者の方向から見ると消光状態が得られるように、
各々の偏光板３３，３６が調整されている。 An eighth modification of this embodiment will be described with reference to FIGS. 1 and 6 . In this modification , a configuration for estimating the absolute amount of the birefringence phase difference is added at a position set as a reference in the two-dimensional test space. In FIG.
Reference numeral 31 is a white light source unit, 32 is a circular polarizer comprising a polarizing plate 33 and a λ / 4 plate 34, and 35 is a polarizing plate 36 and a λ / 4 plate 3
7 is a circular polarizer. As a result, the test object 1 is irradiated with circularly polarized light, and when there is no birefringence of the test object 1, the extinction state is obtained when viewed from the direction of the observer in the figure.
The respective polarizing plates 33 and 36 are adjusted.
【００７６】ここに、円偏光による干渉のため、図の観
察者の方向から観察される光弾性干渉縞は被検物１の位
相差のみの影響を受けており、また、光源に白色光源ユ
ニット３１を用いているので、干渉縞が着色して観察さ
れる。λ／４板３４，３７には波長依存性があるため、
中心波長からずれるに従い若干の誤差を生ずるものの、
干渉色と位相差とには一定の関係（ニュートンのカラー
スケールなど）があるので、この干渉縞を見ることによ
って、２次元被検空間内の基準位置における位相差の大
凡の推定が可能である。Here, because of interference due to circularly polarized light, the photoelastic interference fringes observed from the direction of the observer in the figure are affected only by the phase difference of the object 1 to be examined, and the white light source unit is used as the light source. Since 31 is used, interference fringes are colored and observed. Since the λ / 4 plates 34 and 37 have wavelength dependence,
Although it causes some error as it deviates from the center wavelength,
Since the interference color and the phase difference have a constant relationship (Newton's color scale, etc.), it is possible to roughly estimate the phase difference at the reference position in the two-dimensional inspection space by looking at this interference fringe. .
【００７７】そこで、前述したような測定方法により得
られる位相差測定結果をδとすると、その絶対量Δは、
前述の(12)式で表され、整数ｎが特定できれば位相差の
絶対量Δを求めることができる。Therefore, when the phase difference measurement result obtained by the above-described measuring method is δ, the absolute amount Δ is
The absolute amount Δ of the phase difference can be obtained if the integer n can be specified by the above-mentioned equation (12).
【００７８】図５に示した構成による干渉縞の観察によ
り位相差が採るべき大凡の範囲を推定できるため、その
範囲に入るようにして、（12）式の整数ｎを決定するこ
とができる。By observing the interference fringes with the configuration shown in FIG. 5, the approximate range in which the phase difference should be taken can be estimated, so that the integer n in equation (12) can be determined so that it falls within that range.
【００７９】従って、手順としては、まず、図１に示し
たような複屈折測定装置により被検物１の複屈折位相差
の２次元空間分布を測定した後、図５に示すような構成
を用いて、任意に設定した２次元被検空間内での基準位
置における複屈折位相差の絶対量を推定、即ち、基準位
置における整数ｎを決定する。次に、その整数ｎを先に
測定した２次元空間分布の測定値全てに適用すること
で、２次元空間全体における複屈折位相差の絶対量を知
ることができる。Therefore, the procedure is as follows. First, the two-dimensional spatial distribution of the birefringence phase difference of the test object 1 is measured by the birefringence measuring apparatus as shown in FIG. It is used to estimate the absolute amount of the birefringence phase difference at the reference position in the arbitrarily set two-dimensional test space, that is, to determine the integer n at the reference position. Next, by applying the integer n to all the measured values of the two-dimensional spatial distribution measured previously, the absolute amount of the birefringence phase difference in the entire two-dimensional space can be known.
【００８０】なお、２次元被検空間内での基準位置にお
ける複屈折位相差の絶対量を知る（推定する）方法とし
ては、干渉色からの判別法以外にも、例えば、回転検光
子法などの点測定法において光源に多波長を用いて測定
するようにしてもよい。As a method of knowing (estimating) the absolute amount of the birefringence phase difference at the reference position in the two-dimensional space to be examined, other than the discrimination method from the interference color, for example, the rotation analyzer method or the like is used. In the point measurement method, the measurement may be performed using multiple wavelengths for the light source.
【００８１】本実施の形態の第九の変形例について説明
する。 A ninth modification of the present embodiment will be described .
【００８２】本変形例は、被検物１がレーザプリンタ等
における書込み光学系用のレンズのような場合に適用さ
れる。このような場合、被検物１は複数のレンズからな
るレンズ群により構成される。ここに、各レンズの持つ
複屈折の相乗効果が書込み光学系の実使用状態において
レンズ群を透過するビームに影響を与えるので、レンズ
群としての実使用状態での複屈折測定値が透過ビームを
評価する上で有効な情報となる。そこで、本変形例で
は、このようなレンズ群の各々をその実使用状態と同様
にベース上にレイアウトしてからベースを図１に示した
複屈折測定装置にセットして、図１における被検物１
(レンズ群)に発散光を照射するレンズ４と被検物１との
間隔を、書込み光学系における実使用時の点光源とレン
ズ群との間隔に相当するようセットしてから測定を実施
する。これにより、レンズ群に関しても、より実使用に
則した状態での複屈折が測定、評価可能となる。This modification is applied to the case where the object 1 is a lens for a writing optical system in a laser printer or the like. In such a case, the test object 1 is composed of a lens group including a plurality of lenses. Since the synergistic effect of the birefringence of each lens affects the beam that passes through the lens group in the actual use state of the writing optical system, the birefringence measurement value in the actual use state of the lens group indicates the transmitted beam. This information is useful for evaluation. Therefore, in the present modification , each of such lens groups is laid out on the base in the same manner as in the actually used state, and then the base is set in the birefringence measuring apparatus shown in FIG. Object 1 in 1
The measurement is performed after setting the distance between the lens 4 for irradiating the (lens group) with divergent light and the test object 1 so as to correspond to the distance between the point light source and the lens group during actual use in the writing optical system. . As a result, it is possible to measure and evaluate the birefringence of the lens group in a state more practically used.
【００８３】[0083]
【発明の効果】請求項１、２記載の発明によれば、被検
物表面における汚れ等のノイズの影響を受けにくい複屈
折測定が可能となる。Effects of the Invention According to the present invention, 2 Symbol placement, it is possible to hardly affected by birefringence measurement noise such as dirt in the surface of the test object.
【００８４】請求項３〜１１記載の発明によれば、被検
物表面における汚れ等のノイズの影響を受けにくい複屈
折測定が可能となる上に、被検物がレンズのように曲率
をもつ場合でも簡単、短時間、高い空間分解能で、か
つ、高精度な測定が可能となる。 [0084] According to the invention of claim 3 to 11 wherein, subject
Double bending that is not easily affected by noise such as dirt on the surface of an object
In addition to being able to measure folding, the object to be measured is curved like a lens.
Even if you have a simple, short time, high spatial resolution,
Therefore, highly accurate measurement becomes possible.
【００８５】特に、請求項３、４記載の発明によれば、
被検レンズの種類の変更に対する汎用性を高めることが
できる。 Particularly, according to the inventions of claims 3 and 4 ,
The versatility with respect to the change of the type of the lens to be inspected can be enhanced.
【００８６】また、請求項１１記載の発明によれば、被
検領域内において被検物の複屈折の変化が大きい場合で
も、測定レンジの拡大が可能となる。[0086] Also, according to the invention of claim 11 wherein, even when the change in the birefringence of the test object in the test area is large, it is possible to expand the measurement range.
【図１】本発明の各実施の形態で用いる複屈折測定装置
を示す構成図である。FIG. 1 is a configuration diagram showing a birefringence measuring device used in each embodiment of the present invention.
【図２】測定対象領域の分割の様子を示す正面図であ
る。FIG. 2 is a front view showing how the measurement target area is divided.
【図３】補正光学系による作用を説明するための図であ
り、（ａ）は主走査方向に見た平面図、（ｂ）は副走査
方向に見た側面図である。3A and 3B are views for explaining the action of the correction optical system, FIG. 3A is a plan view seen in the main scanning direction, and FIG. 3B is a side view seen in the sub-scanning direction.
【図４】位相差測定結果の補正前後の断面分布を示す特
性図である。FIG. 4 is a characteristic diagram showing a cross-sectional distribution before and after correction of a phase difference measurement result.
【図５】楕円偏光の長軸方向を説明するための説明図で
ある。FIG. 5 is an explanatory diagram for explaining a major axis direction of elliptically polarized light.
【図６】複屈折位相差の絶対量を推定するための構成を
示す光学系側面図である。FIG. 6 is a side view of an optical system showing a configuration for estimating an absolute amount of birefringence phase difference.
１ 被検物 ２ 光源 ５ 照射光学系 ７ 検光子 ９ 受光素子アレイ、受光手段 １２ 回転手段 １６ 結像光学系 １７ 移相子 ２０ 受光ベース ２１ ベース ２４ ベース移動手段 1 Object 2 light sources 5 Irradiation optical system 7 Analyzer 9 Light receiving element array, light receiving means 12 rotation means 16 Imaging optical system 17 Phase shifter 20 light receiving base 21 base 24 Base transportation
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G01M 11/00 - 11/08 G01N 21/17 - 21/61 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields investigated (Int.Cl. 7 , DB name) G01M 11/00-11/08 G01N 21/17-21/61
Claims (11)
記被検物を透過した光束を検光子のみを介して受光手段
により受光するとともに前記検光子を回転させたときに
得られる光強度変化より求めた被検物透過光の偏光情報
と、前記被検物を透過した光束を移相子と前記検光子と
を介して前記受光手段により受光するとともに前記検光
子を回転させたときに得られる光強度変化より求めた被
検物透過光の偏光情報との、両偏光情報に基づき前記被
検物の複屈折を求めるようにした複屈折測定方法であっ
て、任意に設定した被検領域内での基準位置における複
屈折位相差の絶対量を推定し、推定された複屈折位相差
の絶対量を測定された複屈折位相差の２次元空間分布の
測定値全てに適用して被検領域全体における複屈折位相
差の絶対量を測定するようにした複屈折測定方法。1. Obtained when substantially circularly polarized light is radiated to an object to be inspected, a light beam transmitted through the object to be inspected is received by a light receiving means via only the analyzer, and the analyzer is rotated. The polarization information of the transmitted light of the test object obtained from the change of the light intensity, and the light beam transmitted through the test object is received by the light receiving means via the phase shifter and the analyzer, and the analyzer is rotated. met birefringence measuring method so as to obtain the polarization information of the object transmitted light obtained from the light intensity changes resulting, the birefringence of the test object based on both the polarization information when
The reference position within the arbitrarily set test area.
Estimate the absolute amount of refraction phase difference and estimate the birefringence phase difference
Of the two-dimensional spatial distribution of the birefringence retardation measured by the absolute amount of
Birefringence phase applied to all measured values
A birefringence measuring method adapted to measure the absolute amount of difference .
退させることで、前記被検物から前記受光手段までの光
路に前記移相子が介在される状態と介在されない状態と
を生成するようにした請求項１記載の複屈折測定方法。2. By advancing and retracting the retarder in a direction other than the optical axis of the optical system, a state where the retarder is interposed and a state where the retarder is not interposed are provided in an optical path from the object to be measured to the light receiving means. The method for measuring birefringence according to claim 1, wherein the birefringence is generated.
めの光源と、 前記被検物を透過した透過光の偏光状態を変化させる移
相子と、 この移相子を透過した光の偏光状態を検知するための検
光子と、 この検光子を透過した光を受光する複数の受光素子が並
設された受光素子アレイよりなる受光手段と、 前記被検物を透過した透過光の光束を常に光軸に対して
ほぼ平行にするための照射光学系と、 前記被検物を透過した光を前記受光素子アレイの受光面
上に結像させるための結像光学系と、 前記被検物から前記受光手段までの光路上に前記移相子
が介在される状態と介在されない状態とを生成する移相
子進退切換手段と、 前記検光子をその光軸回りに回転させる回転手段と、 この回転手段による前記検光子の回転角度を検知する回
転角検知手段と、 前記被検物を保持する保持手段と、 前記受光手段により受光検出される受光出力と前記回転
角検知手段により検知された回転角度とに基づき前記被
検物の複屈折を算出する演算手段と、 を備え、前記照射光学系が、組合せ自在な複数の光学系
よりなる 複屈折測定装置。3. An object to be inspected is irradiated with substantially circularly polarized light.
And a light source for changing the polarization state of the transmitted light transmitted through the test object.
A detector for detecting the phase and the polarization state of light transmitted through this phase shifter.
A photon and multiple photo detectors that receive the light that has passed through this analyzer are arranged side by side.
The light receiving means composed of a light receiving element array provided, and the light flux of the transmitted light that has passed through the object to be measured is always aligned with the optical axis.
An irradiation optical system for making the light beams substantially parallel to each other, and a light receiving surface of the light receiving element array for transmitting the light transmitted through the test object.
An image forming optical system for forming an image on the upper side, and the retarder on the optical path from the object to be measured to the light receiving means.
Phase shift that generates a state in which the
Child advance / retreat switching means, rotation means for rotating the analyzer around its optical axis, and a rotation detecting means for detecting the rotation angle of the analyzer by the rotation means.
Rotation angle detecting means, holding means for holding the object to be inspected, light receiving output detected by the light receiving means, and the rotation
Based on the rotation angle detected by the angle detection means,
Comprising calculating means for calculating the birefringence of test object, wherein the illumination optical system, a combination freely plurality of optical systems
A birefringence measuring device consisting of .
めの光源と、 前記被検物を透過した透過光の偏光状態を変化させる移
相子と、 この移相子を透過した光の偏光状態を検知するための検
光子と、 この検光子を透過した光を受光する複数の受光素子が並
設された受光素子アレイよりなる受光手段と、 前記被検物を透過した透過光の光束を常に光軸に対して
ほぼ平行にするための照射光学系と、 前記被検物を透過した光を前記受光素子アレイの受光面
上に結像させるための結像光学系と、 前記被検物から前記受光手段までの光路上に前記移相子
が介在される状態と介在されない状態とを生成する移相
子進退切換手段と、 前記検光子をその光軸回りに回転させる回転手段と、 この回転手段による前記検光子の回転角度を検知する回
転角検知手段と、 前記被検物を保持する保持手段と、 前記受光手段により受光検出される受光出力と前記回転
角検知手段により検知された回転角度とに基づき前記被
検物の複屈折を算出する演算手段と、 を備え、 前記被検物に対する前記照射光学系の光軸方向の位置を
移動調整する移動手段と、 前記照射光学系の光軸方向における位置を検知する検知
手段と、 を備える 複屈折測定装置。4. An object is irradiated with substantially circularly polarized light.
And a light source for changing the polarization state of the transmitted light transmitted through the test object.
A detector for detecting the phase and the polarization state of light transmitted through this phase shifter.
A photon and multiple photo detectors that receive the light that has passed through this analyzer are arranged side by side.
The light receiving means composed of a light receiving element array provided, and the light flux of the transmitted light that has passed through the object to be measured is always aligned with the optical axis.
An irradiation optical system for making the light beams substantially parallel to each other, and a light receiving surface of the light receiving element array for transmitting the light transmitted through the test object.
An image forming optical system for forming an image on the upper side, and the retarder on the optical path from the object to be measured to the light receiving means.
Phase shift that generates a state in which the
Child advance / retreat switching means, rotation means for rotating the analyzer around its optical axis, and a rotation detecting means for detecting the rotation angle of the analyzer by the rotation means.
Rotation angle detecting means, holding means for holding the object to be inspected, light receiving output detected by the light receiving means, and the rotation
Based on the rotation angle detected by the angle detection means,
An arithmetic means for calculating the birefringence of the test object; and a position in the optical axis direction of the irradiation optical system with respect to the test object.
Moving means for moving and adjusting, and detection for detecting the position of the irradiation optical system in the optical axis direction
Birefringence measurement apparatus comprising a means.
光学系よりなる請求項４記載の複屈折測定装置。 5. The irradiation optical system includes a plurality of freely combinable irradiation optical systems.
The birefringence measuring device according to claim 4, which comprises an optical system .
めの光源と、 前記被検物を透過した透過光の偏光状態を変化させる移
相子と、 この移相子を透過した光の偏光状態を検知するための検
光子と、 この検光子を透過した光を受光する複数の受光素子が並
設された受光素子アレイよりなる受光手段と、 前記被検物を透過した透過光の光束を常に光軸に対して
ほぼ平行にするための照射光学系と、 前記被検物を透過した光を前記受光素子アレイの受光面
上に結像させるための結像光学系と、 前記被検物から前記受光手段までの光路上に前記移相子
が介在される状態と介在されない状態とを生成する移相
子進退切換手段と、 前記検光子をその光軸回りに回転させる回転手段と、 この回転手段による前記検光子の回転角度を検知する回
転角検知手段と、 前記被検物を保持する保持手段と、 前記受光手段により受光検出される受光出力と前記回転
角検知手段により検知された回転角度とに基づき前記被
検物の複屈折を算出する演算手段と、 を備え、 前記移相子、検光子、受光素子アレイ、移相子進退切換
手段、回転手段、回転角検知手段及び結像光学系を一体
にして搭載したベースと、 このベースを光学系光軸とほぼ垂直方向に移動させるベ
ース移動手段と、 このベース移動手段より移動する前記ベースの光学系光
軸と垂直方向における位置を検知するベース位置検知手
段と、 を備える 複屈折測定装置。6. A test object is irradiated with substantially circularly polarized light.
And a light source for changing the polarization state of the transmitted light transmitted through the test object.
A detector for detecting the phase and the polarization state of light transmitted through this phase shifter.
A photon and multiple photo detectors that receive the light that has passed through this analyzer are arranged side by side.
The light receiving means composed of a light receiving element array provided, and the light flux of the transmitted light that has passed through the object to be measured is always aligned with the optical axis.
An irradiation optical system for making the light beams substantially parallel to each other, and a light receiving surface of the light receiving element array for transmitting the light transmitted through the test object.
An image forming optical system for forming an image on the upper side, and the retarder on the optical path from the object to be measured to the light receiving means.
Phase shift that generates a state in which the
Child advance / retreat switching means, rotation means for rotating the analyzer around its optical axis, and a rotation detecting means for detecting the rotation angle of the analyzer by the rotation means.
Rotation angle detecting means, holding means for holding the object to be inspected, light receiving output detected by the light receiving means, and the rotation
Based on the rotation angle detected by the angle detection means,
Comprising calculating means for calculating the birefringence of test object, wherein the retarder, an analyzer, a light receiving element array, the retarder retractable switching
Means, rotation means, rotation angle detection means, and imaging optical system
And the base mounted to move the base almost perpendicular to the optical axis of the optical system.
Source moving means and the optical system light of the base moving from the base moving means.
Base position detection hand that detects the position in the direction perpendicular to the axis
Birefringence measuring apparatus comprising: a stage, a.
めの光源と、 前記被検物を透過した透過光の偏光状態を変化させる移
相子と、 この移相子を透過した光の偏光状態を検知するための検
光子と、 この検光子を透過した光を受光する複数の受光素子が並
設された受光素子アレイよりなる受光手段と、 前記被検物を透過した透過光の光束を常に光軸に対して
ほぼ平行にするための照射光学系と、 前記被検物を透過した光を前記受光素子アレイの受光面
上に結像させるための結像光学系と、 前記被検物から前記受光手段までの光路上に前記移相子
が介在される状態と介在されない状態とを生成する移相
子進退切換手段と、 前記検光子をその光軸回りに回転させる回転手段と、 この回転手段による前記検光子の回転角度を検知する回
転角検知手段と、 前記被検物を保持する保持手段と、 前記受光手段により受光検出される受光出力と前記回転
角検知手段により検知された回転角度とに基づき前記被
検物の複屈折を算出する演算手段と、 を備え、 前記被検物を保持する前記保持手段を光学系光軸とほぼ
垂直方向に移動させる保持手段移動手段と、 この保持手段移動手段より移動する前記保持手段の光学
系光軸と垂直方向における位置を検知する保持手段位置
検知手段と、 を備える 複屈折測定装置。7. A test object is irradiated with substantially circularly polarized light.
And a light source for changing the polarization state of the transmitted light transmitted through the test object.
A detector for detecting the phase and the polarization state of light transmitted through this phase shifter.
A photon and multiple photo detectors that receive the light that has passed through this analyzer are arranged side by side.
The light receiving means composed of a light receiving element array provided, and the light flux of the transmitted light that has passed through the object to be measured is always aligned with the optical axis.
An irradiation optical system for making the light beams substantially parallel to each other, and a light receiving surface of the light receiving element array for transmitting the light transmitted through the test object.
An image forming optical system for forming an image on the upper side, and the retarder on the optical path from the object to be measured to the light receiving means.
Phase shift that generates a state in which the
Child advance / retreat switching means, rotation means for rotating the analyzer around its optical axis, and a rotation detecting means for detecting the rotation angle of the analyzer by the rotation means.
Rotation angle detecting means, holding means for holding the object to be inspected, light receiving output detected by the light receiving means, and the rotation
Based on the rotation angle detected by the angle detection means,
Comprising calculating means for calculating the birefringence of test object, wherein the substantially the optical axis of the optical system the holding means for holding a specimen
Holding means moving means for moving in the vertical direction, and optical of the holding means moved by the holding means moving means.
Position of holding means for detecting the position in the direction perpendicular to the optical axis of the system
A birefringence measuring device comprising: a detecting unit .
移相子進退切換手段、回転手段、回転角検知手段及び結
像光学系を一体にして搭載したベースと、 このベースを光学系光軸とほぼ垂直方向に移動させるベ
ース移動手段と、 このベース移動手段より移動する前記ベースの光学系光
軸と垂直方向における位置を検知するベース位置検知手
段と、 を備える 請求項３又は４記載の複屈折測定装置。 8. A phase shifter, an analyzer, a light receiving element array,
Phase shifter advance / retreat switching means, rotation means, rotation angle detection means and connection
A base with an integrated image optical system and a base for moving this base in a direction almost perpendicular to the optical axis of the optical system.
Source moving means and the optical system light of the base moving from the base moving means.
Base position detection hand that detects the position in the direction perpendicular to the axis
The birefringence measuring device according to claim 3 , further comprising a step .
学系光軸とほぼ垂直方向に移動させる保持手段移動手段
と、 この保持手段移動手段より移動する前記保持手段の光学
系光軸と垂直方向における位置を検知する保持手段位置
検知手段と、 を備える請求項３又は４記載の 複屈折測定装置。9. The holding means for holding the object to be examined is lighted.
Holding means for moving in a direction almost perpendicular to the optical axis
And the optical of the holding means moving from the holding means moving means.
Position of holding means for detecting the position in the direction perpendicular to the optical axis of the system
The birefringence measuring apparatus according to claim 3 or 4 , further comprising: a detecting unit .
とを一体にして搭載した受光ベースを備える請求項６、
７、８又は９記載の複屈折測定装置。 10. The image forming optical system and the light receiving element array
7. A light-receiving base comprising :
The birefringence measuring device according to 7, 8 or 9 .
である請求項３、４ 、５、６、７、８又は９記載の複屈
折測定装置。11. The imaging magnification of the imaging optical system can be freely changed.
In a claim 3,4, 5, 6, 7, 8 or 9 birefringence measuring apparatus according.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08300799A JP3456695B2 (en) | 1999-03-26 | 1999-03-26 | Birefringence measuring method and apparatus therefor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08300799A JP3456695B2 (en) | 1999-03-26 | 1999-03-26 | Birefringence measuring method and apparatus therefor |
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| JP3456695B2 true JP3456695B2 (en) | 2003-10-14 |
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|---|---|---|---|
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