JPH06337235A - Image surface measuring apparatus - Google Patents
Image surface measuring apparatusInfo
- Publication number
- JPH06337235A JPH06337235A JP6292194A JP6292194A JPH06337235A JP H06337235 A JPH06337235 A JP H06337235A JP 6292194 A JP6292194 A JP 6292194A JP 6292194 A JP6292194 A JP 6292194A JP H06337235 A JPH06337235 A JP H06337235A
- Authority
- JP
- Japan
- Prior art keywords
- diffraction grating
- measured
- light
- image plane
- diffracted
- 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.)
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Links
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- Testing Of Optical Devices Or Fibers (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、カメラレンズ等により
形成される像面の状態を測定する像面測定装置に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image plane measuring device for measuring the state of an image plane formed by a camera lens or the like.
【０００２】[0002]
【従来技術およびその問題点】複数のレンズ素子から構
成される撮影レンズ系では、レンズ素子が１個でも偏心
ないし傾斜すると、これが結像系である場合には像面に
倒れを生じ、さらに諸収差のバランスが崩れて結像性能
が劣化する。つまり、被写体像が、画面中央付近ではフ
ィルム面上に結像するが、周辺部ではフィルム面の前方
または後方に結像してしまい、撮影画面の周辺がボケる
という問題を生じてしまう。そのため、各レンズ素子を
偏心および傾斜しないようにレンズ鏡筒に対して正確に
位置決めする必要がある。2. Description of the Related Art In a photographing lens system composed of a plurality of lens elements, even if only one lens element is eccentric or tilted, if it is an image forming system, the image plane is tilted, and further various points are caused. The aberration balance is lost and the imaging performance deteriorates. That is, the subject image is formed on the film surface in the vicinity of the center of the screen, but is imaged in front of or behind the film surface in the peripheral portion, which causes a problem that the periphery of the photographic screen is blurred. Therefore, it is necessary to accurately position each lens element with respect to the lens barrel so as not to decenter and tilt.
【０００３】しかしながら、レンズ素子の組付け時の機
械的精度を向上させるためには、各部品の精度や、組付
けの精度が高く要求され、コスト、時間がかかるという
問題があった。したがって、レンズ素子を鏡筒などに組
み付けた後に像面の傾斜を簡単に測定できる装置が望ま
れていた。However, in order to improve the mechanical accuracy when assembling the lens element, the accuracy of each component and the accuracy of assembly are required to be high, and there is a problem that cost and time are required. Therefore, there has been a demand for an apparatus that can easily measure the tilt of the image plane after the lens element is mounted on a lens barrel or the like.
【０００４】[0004]
【発明の目的】本発明は、上記従来技術の問題に鑑みて
なされたもので、レンズにより形成される像面の傾きを
簡単かつ迅速に検出できる像面測定装置を提供すること
を目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an image plane measuring apparatus capable of simply and quickly detecting the inclination of the image plane formed by a lens. .
【０００５】[0005]
【発明の概要】この目的を達成する請求項１に記載の発
明は、被測定光学系に測定光を照射する測定光源と、前
記被測定光学系の前に配置され、前記測定光源から発し
た測定光を回折させる回折格子と、この回折格子を光軸
と平行な軸を中心に回転させる回転機構と、前記被測定
光学系の焦点位置に配置され、前記回折格子で回折して
被測定光学系を透過した回折光を反射する基準反射面
と、この基準反射面で反射され、前記被測定光学系およ
び前記回折格子を介して合成された異なる次数の回折光
により形成される干渉縞を、前記回折格子を回転させな
がら検出する検出手段と、を備えたことに特徴を有す
る。SUMMARY OF THE INVENTION In order to achieve this object, the invention according to claim 1 is a measurement light source for irradiating an optical system to be measured with measurement light, and a measurement light source which is arranged in front of the optical system to be measured. A diffraction grating that diffracts the measurement light, a rotating mechanism that rotates the diffraction grating about an axis parallel to the optical axis, and a diffraction grating that is arranged at the focal position of the measured optical system and diffracted by the diffraction grating to measure the measured optical system. A reference reflection surface that reflects the diffracted light that has passed through the system, and an interference fringe that is reflected by this reference reflection surface and that is formed by diffracted light of different orders synthesized via the optical system to be measured and the diffraction grating, And a detection unit that detects the diffraction grating while rotating the diffraction grating.
【０００６】請求項２に記載の発明は、測定光源から照
射された測定光を回折させる回折格子と、この回折格子
で回折された回折光を被測定光学系の被測定結像面に結
像させる基準レンズと、前記被測定結像面に配置され、
前記回折光を反射する基準反射面と、前記回折格子を前
記基準レンズの光軸と平行な軸を中心に回転させる回転
機構と、前記基準反射面で反射され、前記基準光学系お
よび前記回折格子を介して合成された異なる次数の回折
光により形成される干渉縞を、前記回折格子を回転させ
ながら検出する検出手段と、を備えたことに特徴を有す
る。According to a second aspect of the present invention, a diffraction grating for diffracting the measurement light emitted from the measurement light source and the diffracted light diffracted by the diffraction grating are formed on the measurement image forming plane of the measurement optical system. And a reference lens, which is arranged on the measured image plane,
A reference reflection surface that reflects the diffracted light, a rotation mechanism that rotates the diffraction grating about an axis parallel to the optical axis of the reference lens, and the reference optical system and the diffraction grating that are reflected by the reference reflection surface. It is characterized in that an interference fringe formed by diffracted light of different orders synthesized through is detected by rotating the diffraction grating.
【０００７】[0007]
【実施例】以下図示実施例に基づいて本発明を説明す
る。図１および図２は、本発明を適用した像面測定装置
の実施例の光学的構成を示す光路図である。図１は、被
測定光学系としての被測定レンズ１７を測定する測定装
置、図２は、基準レンズ１８によりカメラ４１のフィル
ム面における像面の状態を測定する測定装置である。両
測定装置は、基本的構成は同一なので、共通の構成は図
１に示した実施例に基づいて説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. 1 and 2 are optical path diagrams showing an optical configuration of an embodiment of an image plane measuring apparatus to which the present invention is applied. 1 shows a measuring device for measuring a lens 17 to be measured as an optical system to be measured, and FIG. 2 shows a measuring device for measuring a state of an image plane on a film surface of a camera 41 by a reference lens 18. Since both measuring devices have the same basic structure, the common structure will be described based on the embodiment shown in FIG.
【０００８】レーザ光源１１から照射された平行光線束
は、ハーフミラー１３を透過して回折格子１５により回
折され、回折光が被測定レンズ１７により基準反射面１
９に結像される。基準反射面１９は、±一次回折光のみ
を反射し、他の次数の回折光を吸収または透過するもの
で、被測定レンズ１７の焦点位置またはその近傍に、被
測定レンズ１７の光軸Ｏ（理想光軸）と直交する向きに
配置されている。なお、この実施例では被測定レンズ１
７は無限遠に合焦する状態に調整してある。The parallel light flux emitted from the laser light source 11 passes through the half mirror 13 and is diffracted by the diffraction grating 15, and the diffracted light is reflected by the lens 17 to be measured on the reference reflection surface 1.
9 is imaged. The reference reflecting surface 19 reflects only ± first-order diffracted light and absorbs or transmits diffracted light of other orders, and the optical axis O (of the measured lens 17 is located at or near the focal position of the measured lens 17. It is arranged in a direction orthogonal to the ideal optical axis). In addition, in this embodiment, the lens to be measured 1
No. 7 is adjusted to focus on infinity.
【０００９】基準反射面１９は、円形の中心部分１９
ａ、これと同心の環状の反射部分１９ｂおよび外方部分
１９ｃを備えている。反射部分１９ｂは、入射光を反射
するが、中心部分１９ａおよび外方部分１９ｂは入射光
を吸収して反射しない。つまり基準反射面１９は、中心
を光軸Ｏと一致させた状態で、反射部分１９ｂに±一次
回折光が入射し、中心部分１９ａに０次回折光が入射
し、外方部分１９ｃに他の次数の回折光が入射するよう
に形成してある。なお、基準反射面１９は、±一次回折
光のみを反射し、他の次数の回折光は透過する構成でも
よい。The reference reflecting surface 19 has a circular center portion 19
a, an annular reflecting portion 19b and an outer portion 19c which are concentric therewith. The reflecting portion 19b reflects the incident light, but the central portion 19a and the outer portion 19b absorb the incident light and do not reflect it. That is, with the center of the reference reflecting surface 19 aligned with the optical axis O, ± first-order diffracted light enters the reflecting portion 19b, 0-th order diffracted light enters the central portion 19a, and other orders enter the outer portion 19c. It is formed so that the diffracted light of is incident. The reference reflection surface 19 may be configured to reflect only ± first-order diffracted light and transmit diffracted light of other orders.
【００１０】基準反射面１９の反射部１９ｂで反射され
た±１次回折光は、光路を逆行して再び被測定レンズ１
７を透過し、回折格子１５で回折され、ハーフミラー１
３で結像レンズ２１方向に反射される。そして、回折格
子１５により、往路で＋１次方向に回折されさらに復路
で−１次方向に回折された回折光、および往路で−１次
方向に回折され復路で＋１次方向に回折された回折光の
みが、結像レンズ２１の焦点位置に配設された空間フィ
ルタ２３により選択透過され、測定面２５上に集束され
る。観察面２５上に結像された±１次回折光により形成
される干渉縞（図５参照）がフォトディテクタ２７によ
り光電変換され、その強度が電気信号によるデータとし
て出力される。空間フィルタ２３は、中央に上記±１次
回折光のみを透過させる孔２３ａを有する。孔２３ａの
周辺部分２３ｂは、入射光を吸収する。The ± first-order diffracted light reflected by the reflecting portion 19b of the reference reflecting surface 19 travels backward in the optical path and the lens 1 to be measured again.
7 and is diffracted by the diffraction grating 15, and the half mirror 1
3 is reflected in the direction of the imaging lens 21. Then, by the diffraction grating 15, the diffracted light that is diffracted in the + first order direction on the outward path and further diffracted in the −1st order direction on the return path, and the diffracted light that is diffracted in the −first order direction on the outward path and diffracted in the + first order direction on the return path. Only the light is selectively transmitted by the spatial filter 23 arranged at the focal position of the imaging lens 21 and focused on the measurement surface 25. The interference fringes (see FIG. 5) formed by the ± first-order diffracted lights imaged on the observation surface 25 are photoelectrically converted by the photodetector 27, and the intensity thereof is output as data by an electric signal. The spatial filter 23 has a hole 23a in the center for transmitting only the ± first-order diffracted light. The peripheral portion 23b of the hole 23a absorbs incident light.
【００１１】回折格子１５は、所定ピッチ（Pitch ）の
スリット格子であり、被測定レンズ１７のほぼ前側焦点
位置に光軸Ｏと直交方向に配置され、回転機構２９によ
り光軸０または光軸Ｏと平行な軸を中心に回転可能に保
持されている。フォトディテクタ２７が出力した電気信
号は、マイクロコンピュータ等の画像処理装置で画像処
理して、記録媒体に記録し、あるいはディスプレイに表
示して像面の倒れを視覚的に観察する。The diffraction grating 15 is a slit grating having a predetermined pitch (Pitch), and is arranged in a direction substantially orthogonal to the optical axis O at a focal position on the front side of the lens 17 to be measured, and is rotated by the rotating mechanism 29 to the optical axis 0 or O. It is held rotatably about an axis parallel to. The electric signal output from the photodetector 27 is subjected to image processing by an image processing device such as a microcomputer and recorded on a recording medium or displayed on a display to visually observe the tilt of the image plane.
【００１２】図１の測定装置は、被測定レンズ１７の状
態を測定する態様であったが、図２の実施例は、結像光
学系が理想状態または理想状態に近い状態にあるときの
被測定光学系の結像面の状態を測定する態様である。こ
の実施例では、一眼レフカメラ４１において、基準レン
ズ１８が理想状態にあるときのフィルム面上における結
像状態を測定する。この測定により、基準レンズ１８に
対するフィルム面の傾き、あるいはボディマウント面４
３とフィルム面の基準となるフィルムガイドレール４３
との平行度、光軸と直交する方向のずれなどが分かる。The measuring apparatus of FIG. 1 has a mode in which the state of the lens 17 to be measured is measured, but the embodiment of FIG. 2 measures the state when the imaging optical system is in the ideal state or a state close to the ideal state. In this mode, the state of the image plane of the measurement optical system is measured. In this embodiment, the single-lens reflex camera 41 measures the image formation state on the film surface when the reference lens 18 is in the ideal state. By this measurement, the inclination of the film surface with respect to the reference lens 18 or the body mount surface 4
3 and the film guide rail 43 serving as a reference for the film surface
You can see the parallelism with, and the deviation in the direction orthogonal to the optical axis.
【００１３】測定に際しては、基準レンズ１８は無限遠
合焦状態とし、ミラー４７をアップし、裏蓋（図示せ
ず）を開いたあるいは装着前の状態で測定装置本体（図
示せず）にセットする。そして、フィルムガイドレール
４３（外レール）に圧板と同様に基準反射面１９１を当
て付ける。つまり、基準反射面１９１は、装填されたフ
ィルム感光面と等価になる。なお、基準反射面１９１の
基本的構成は基準反射面１９と同一である。At the time of measurement, the reference lens 18 is focused at infinity, the mirror 47 is raised, and the back cover (not shown) is opened or set on the measuring device main body (not shown) before mounting. To do. Then, the reference reflecting surface 191 is applied to the film guide rail 43 (outer rail) in the same manner as the pressure plate. That is, the reference reflective surface 191 is equivalent to the loaded film photosensitive surface. The basic structure of the reference reflecting surface 191 is the same as that of the reference reflecting surface 19.
【００１４】次に、像面３１の倒れにより発生する±１
次回折光の光路差を、図３を参照して説明する。図３
は、基準反射面１９付近の光路の様子を示してある。同
図において、像面３１は、光軸Ｏを含む面内において基
準反射面１９から反時計方向に角度φだけ倒れている。
この倒れ角φが最大になる光軸周りの回転角θを基準反
射面１９に対する最大傾斜方向とする。本実施例におい
て、回転角θは光軸Ｏと直交する面内の角度、倒れ角φ
は光軸Ｏを含む面内の角度であって、回転角θの初期位
置はＸ軸方向（図面においては紙面に垂直な方向）と
し、倒れ角φは基準反射面１９から測る。Next, ± 1 caused by the tilt of the image plane 31
The optical path difference of the next-order diffracted light will be described with reference to FIG. Figure 3
Shows the state of the optical path near the reference reflecting surface 19. In the figure, the image plane 31 is tilted counterclockwise from the reference reflecting surface 19 by an angle φ in a plane including the optical axis O.
The rotation angle θ around the optical axis at which the tilt angle φ becomes maximum is the maximum inclination direction with respect to the reference reflecting surface 19. In this embodiment, the rotation angle θ is an in-plane angle orthogonal to the optical axis O, and the tilt angle φ is
Is an angle within a plane including the optical axis O, the initial position of the rotation angle θ is in the X-axis direction (direction perpendicular to the paper surface in the drawing), and the tilt angle φ is measured from the reference reflection surface 19.
【００１５】ここで、＋１次回折光は、入射光方向から
見ると、あたかもＡ点から発散（反射）されたように見
える。したがって、Ａ点の基準反射面１９からの長さを
Ｔとすると、実質的に＋１次回折光の光路長は２Ｔだけ
長くなる。一方、−１次回折光は、入射方向から見る
と、あたかもＢ点から発散（反射）されたように見え
る。したがって−１次回折光の光路長は、２Ｔだけ短く
なる。このように＋１次回折光と−１次回折光とでは、
計４Ｔの光路差を生じ、この光路差により、±１次回折
光は、観察面２５上にニュートンリング状の干渉縞を生
じる（図５（Ａ）参照）。フォトディテクタ２７は、破
線２８で囲んだ領域の干渉縞の強度を測定する。Here, the + 1st-order diffracted light appears to have diverged (reflected) from point A when viewed from the incident light direction. Therefore, assuming that the length from the reference reflection surface 19 at the point A is T, the optical path length of the + 1st order diffracted light is substantially increased by 2T. On the other hand, the −1st-order diffracted light appears to have been diverged (reflected) from point B when viewed from the incident direction. Therefore, the optical path length of the −1st order diffracted light is shortened by 2T. Thus, in the + 1st-order diffracted light and the -1st-order diffracted light,
An optical path difference of 4T in total is generated, and due to this optical path difference, ± 1st-order diffracted light produces Newton ring-shaped interference fringes on the observation surface 25 (see FIG. 5A). The photo detector 27 measures the intensity of the interference fringes in the area surrounded by the broken line 28.
【００１６】回折格子１５の初期位置からの回転角θと
光路差Ｐ（θ）、干渉縞Ｉ（θ）（強度）との関係は、
下記式の通りである。 Ｐ（θ）＝４Ｔcos θ …… Ｉ（θ）＝(1/2) Ｉ0[1+cos{(8πＴ／λ)cosθ}] …… ただし、λはレーザ光源の波長、Ｉ0 は平均光強度であ
る。したがって、回折格子１５を回転させると、±１次
回折光の干渉縞は、回転角９０゜につき４Ｔ／λ回明暗
を繰り返す。The relationship between the rotation angle θ of the diffraction grating 15 from the initial position, the optical path difference P (θ), and the interference fringe I (θ) (intensity) is as follows.
The formula is as follows. P (θ) = 4T cos θ ・ ・ ・ I (θ) = (1/2) I 0 [1 + cos {(8πT / λ) cos θ}] ・ ・ ・ where λ is the wavelength of the laser light source and I 0 is the average light Strength. Therefore, when the diffraction grating 15 is rotated, the interference fringes of the ± 1st-order diffracted lights repeat bright and dark 4T / λ times for each rotation angle of 90 °.
【００１７】像面３１が基準反射面１９と一致している
ときの観察平面２５上での干渉縞４１の様子を図４に示
し、図３に示すように像面３１が倒れているときの干渉
縞の様子を図５（Ａ）に示した。回折格子１５を図２の
状態から矢印方向に９０゜回転させると、＋１次回折光
は、紙面に対して０次回折光の真上に、−１次回折光は
紙面に対して０次回折光の真下に来るので、±１次回折
光の光路差が０になる。したがって、観察平面２５上で
の干渉縞は、図５（Ｂ）に示すようにヌル状態に変わ
る。回折格子１５を３６０゜回転させたときの干渉光の
強度変化を、図６ないし図８のグラフに示してある。FIG. 4 shows a state of the interference fringes 41 on the observation plane 25 when the image plane 31 is coincident with the reference reflection plane 19, and when the image plane 31 is tilted as shown in FIG. The appearance of the interference fringes is shown in FIG. When the diffraction grating 15 is rotated 90 ° in the direction of the arrow from the state of FIG. 2, the + 1st-order diffracted light is directly above the 0th-order diffracted light with respect to the paper surface, and the −1st-order diffracted light is directly below the 0th-order diffracted light with respect to the paper surface. Therefore, the optical path difference of the ± 1st order diffracted light becomes zero. Therefore, the interference fringes on the observation plane 25 change to the null state as shown in FIG. The change in the intensity of the interference light when the diffraction grating 15 is rotated 360 ° is shown in the graphs of FIGS.
【００１８】回折格子１５を所定角度回転させる間に生
じる干渉縞Ｉ（θ）の明暗の個数をカウントすることに
より、長さＴが求まる。例えば、回折格子１５を１８０
゜回転させて干渉光の明暗（強度）の変化を検出し、明
暗の回数をカウントする。このカウント値がｎであれ
ば、式、 Ｔ＝ｎλ／８ … により長さＴ、すなわち像面３１の倒れ量が求まる。こ
の倒れ量の大きさにより、被測定レンズ１７の良、不良
が判定できる。像面の倒れ量が最も大きい回転角θが像
面の倒れ方向（最大傾斜方向）である。この像面の倒れ
方向は、明暗が最も粗になる回転角θ0 、つまり、明暗
の周期が最も長い波の頂点に対応する回転角θ0 と一致
する。The length T can be obtained by counting the number of bright and dark interference fringes I (θ) generated while rotating the diffraction grating 15 by a predetermined angle. For example, if the diffraction grating 15 is 180
It is rotated by ° to detect the change in intensity (intensity) of the interference light, and the number of intensities is counted. If this count value is n, the length T, that is, the amount of tilt of the image plane 31 can be obtained by the equation: T = nλ / 8. Based on the magnitude of this amount of tilt, it is possible to determine whether the measured lens 17 is good or bad. The rotation angle θ with the largest amount of tilt of the image plane is the tilt direction (maximum tilt direction) of the image plane. The falling direction of the image plane, the rotation angle theta 0 which brightness is most coarse, that is, consistent with the rotation angle theta 0 the period of light and dark corresponds to the vertex of the longest waves.
【００１９】さらに、以上の測定および演算で求めた発
散点間の光軸方向距離ｄ、倒れ量Ｔ等により、像面３１
の倒れ角φを求めることができる。＋一次光、−一次光
の高さをｙとすると、 φ＝ｔａｎ-1ｄ／２ｙ≒ｄ／２ｙ …… である。ここで、ｄ＝２Ｔ、 ｙ＝λｆ／Pitch であり、式より、Ｔ＝ｎλ／８ である。したがって、これらを上記式に代入して像面
３１の倒れ角φを式、 φ＝８ｎ・Pitch ／ｆ により求めることができる。Further, the image plane 31 is determined by the distance d in the optical axis direction between the divergence points and the tilt amount T obtained by the above measurement and calculation.
The tilt angle φ of can be obtained. Letting y be the height of the + primary light and the −primary light, φ = tan −1 d / 2y≈d / 2y. Here, d = 2T, y = λf / Pitch, and from the equation, T = nλ / 8. Therefore, by substituting these into the above equation, the tilt angle φ of the image plane 31 can be obtained by the equation φ = 8n · Pitch / f 2.
【００２０】被検光学系の各レンズの偏心による像面の
倒れに与える感度を予めシミュレーションしておけば、
以上の測定および演算により求めた倒れ量Ｔおよび倒れ
方向φに基づいて、被検光学系の複数のレンズのうち、
どのレンズをどの方向へどれだけの量調整すればよいか
を演算処理により求めることができる。If the sensitivity given to the tilt of the image plane due to the decentering of each lens of the optical system to be tested is simulated beforehand,
Based on the tilt amount T and the tilt direction φ obtained by the above measurement and calculation, among the plurality of lenses of the test optical system,
Which lens should be adjusted in which direction and by what amount can be obtained by arithmetic processing.
【００２１】図５ないし図７には、回折格子１５を３６
０゜回転させたときの干渉光の強度変化をグラフに示し
てある。図において、回転角θが０゜および１８０゜は
回折格子１５のスリットが紙面に対して直交方向に延び
ている状態、同回転角θが９０゜および２７０゜は回折
格子１５のスリットが紙面と平行に延びている状態であ
る。これらのグラフにおいて、波形のピークは１次回折
光の光路差が２ｎλ／２のときであり、波形の谷は同光
路差が（２ｎ−１）λ／２のときである。そして、明暗
の周期が最も長い波の中央値に相当する角度θが像面３
１の最大傾斜方向である。そして、回折格子１５が１８
０゜回転する間に発生する波数ｎから、式により像面
３１の傾斜量が求まる。In FIGS. 5 to 7, the diffraction grating 15 is shown at 36.
The graph shows the intensity change of the interference light when rotated by 0 °. In the figure, when the rotation angles θ are 0 ° and 180 °, the slits of the diffraction grating 15 extend in a direction orthogonal to the paper surface, and when the rotation angles θ are 90 ° and 270 °, the slits of the diffraction grating 15 are on the paper surface. It is in a state of extending in parallel. In these graphs, the peak of the waveform is when the optical path difference of the first-order diffracted light is 2nλ / 2, and the valley of the waveform is when the optical path difference is (2n−1) λ / 2. Then, the angle θ corresponding to the median value of the waves having the longest light-dark cycle is the image plane 3
The maximum tilt direction is 1. And the diffraction grating 15 is 18
From the wave number n generated during 0 ° rotation, the amount of tilt of the image plane 31 can be obtained by an equation.
【００２２】図６の測定例では、回折格子１５を１８０
゜回転する間に、６回明暗を繰り返している。したがっ
て、Ｔ＝（λ／８）×６＝０．７５λとなる。同様に図
７、図８の測定例では、１０回明暗を繰り返しているの
で、Ｔ＝（λ／８）×１０＝１．２５λとなる。In the measurement example of FIG.
Light and dark are repeated 6 times during the rotation. Therefore, T = (λ / 8) × 6 = 0.75λ. Similarly, in the measurement examples of FIGS. 7 and 8, since light and dark are repeated 10 times, T = (λ / 8) × 10 = 1.25λ.
【００２３】また、図６および図７の実施例では、波形
の最も周期の長い部分がθ≒０゜、１８０゜、３６０゜
のときに表われることから、像面の最大傾斜方向が図２
の像面３１の傾斜と一致することが分かる。また、図８
では、波形の最も周期の長い部分がθ≒６０゜のときに
表われることより、像面３１の最大傾斜方向は、図３の
像面３１を光軸０を中心に回折格子１５と同方向におよ
そ６０゜回転した状態であることが分かる。In the embodiments of FIGS. 6 and 7, the longest part of the waveform appears when θ≈0 °, 180 ° and 360 °, so the maximum tilt direction of the image plane is shown in FIG.
It can be seen that it matches the inclination of the image plane 31 of. Also, FIG.
Since the longest part of the waveform appears when θ≈60 °, the maximum tilt direction of the image plane 31 is the same direction as that of the diffraction grating 15 with the optical axis 0 at the image plane 31 of FIG. It can be seen that it has been rotated by about 60 °.
【００２４】以上、本実施例では、平行なレーザ光を、
回折格子１５を回転しながら回折させて被測定レンズ１
７により基準反射面１９上に結像させ、基準反射面１９
で±１次回折光のみを反射させ、再び回折格子１５で回
折させ、空間フィルタ２３により往路における＋１次回
折光で復路での−１次回折光、および往路における−１
次回折光で復路での＋１次回折光のみを透過させてこれ
らを干渉させ、その干渉縞の強度をフォトディテクタ２
７で測定している。したがって、被測定レンズ１７によ
り形成される像面３１が基準反射面１９に対して傾斜し
ている場合は、干渉縞の強度（明暗）が回折格子１５の
回転に伴って変化するので、その明暗の数をカウントす
ることにより像面の傾斜量の測定ができる。そして、回
折格子１５を所定角度回転している間に変化する干渉縞
の明暗の周期に基づいて、像面の傾斜方向も測定でき
る。As described above, in this embodiment, the parallel laser light is
Lens 1 to be measured by diffracting while rotating diffraction grating 15
7 to form an image on the reference reflection surface 19 and
, Only the ± 1st order diffracted light is reflected, and again diffracted by the diffraction grating 15, and the spatial filter 23 diffracts the + 1st order diffracted light in the outward path and the −1st order diffracted light in the backward path and
Only the + 1st-order diffracted light on the return path is transmitted by the 2nd-order diffracted light to interfere with each other, and the intensity of the interference fringe is measured by the photodetector
It is measured at 7. Therefore, when the image plane 31 formed by the lens-to-be-measured 17 is inclined with respect to the reference reflection surface 19, the intensity (brightness) of the interference fringes changes as the diffraction grating 15 rotates. The amount of tilt of the image plane can be measured by counting the number of. Then, the tilt direction of the image plane can also be measured based on the light-dark cycle of the interference fringes that changes while rotating the diffraction grating 15 by a predetermined angle.
【００２５】[0025]
【発明の効果】以上の通り請求項１に記載の発明は、回
折格子を回転させながら被測定光学系により形成される
干渉縞を測定するので、被測定光学系のレンズ系の傾き
および傾斜方向を簡単に測定できる。請求項２に記載の
発明は、基準レンズを使用するので、被測定光学系の結
像面の傾きおよび傾斜方向を簡単に検出することができ
る。さらに、請求項１および２に記載の発明は、測定光
が回折格子、被測定光学系を２回通るので、±１次光回
折光を干渉させることにより、２倍の精度で検出ができ
る。As described above, according to the first aspect of the present invention, since the interference fringes formed by the optical system to be measured are measured while rotating the diffraction grating, the tilt and tilt directions of the lens system of the optical system to be measured are measured. Can be easily measured. According to the second aspect of the present invention, since the reference lens is used, it is possible to easily detect the inclination and the inclination direction of the image plane of the optical system to be measured. Further, in the inventions described in claims 1 and 2, since the measurement light passes through the diffraction grating and the optical system to be measured twice, it is possible to detect with double accuracy by interfering the ± first-order diffracted light.
【図１】本発明を適用した像面測定装置の一実施例の光
路を示した図である。FIG. 1 is a diagram showing an optical path of an embodiment of an image plane measuring apparatus to which the present invention is applied.
【図２】本発明を適用した像面測定装置の別の実施例の
光路を示した図である。FIG. 2 is a diagram showing an optical path of another embodiment of the image plane measuring apparatus to which the present invention is applied.
【図３】同実施例における基準面付近の様子を拡大して
示す図である。FIG. 3 is an enlarged view showing a state near a reference plane in the example.
【図４】本装置による干渉縞の様子を示す図である。FIG. 4 is a diagram showing a state of interference fringes of the present apparatus.
【図５】本装置による干渉縞の様子を異なる状態で示す
図である。FIG. 5 is a diagram showing a state of interference fringes of the present apparatus in different states.
【図６】回折格子を回転させて干渉縞の強度変化を測定
したグラフを示す図である。FIG. 6 is a diagram showing a graph in which the intensity change of interference fringes is measured by rotating the diffraction grating.
【図７】回折格子を回転させて干渉縞の強度変化を測定
したグラフを示す図である。FIG. 7 is a diagram showing a graph in which the intensity change of interference fringes is measured by rotating the diffraction grating.
【図８】回折格子を回転させて干渉縞の強度変化を測定
したグラフを示す図である。FIG. 8 is a diagram showing a graph in which the intensity change of interference fringes is measured by rotating the diffraction grating.
１１ レーザ光源 １３ ハーフミラー １５ 回折格子 １７ 被測定レンズ（被測定光学系） １８ 基準レンズ １９ 基準反射面 ２３ 空間フィルタ ２５ 観測面 ２７ フォトディテクタ ２９ 回転機構 11 Laser Light Source 13 Half Mirror 15 Diffraction Grating 17 Lens to be Measured (Optical System to be Measured) 18 Reference Lens 19 Reference Reflection Surface 23 Spatial Filter 25 Observation Surface 27 Photo Detector 29 Rotation Mechanism
Claims (7)
源と、 前記被測定光学系の前に配置され、前記測定光源から発
した測定光を回折させる回折格子と、 この回折格子を光軸と平行な軸を中心に回転させる回転
機構と、 前記被測定光学系の焦点位置に配置され、前記回折格子
で回折して被測定光学系を透過した回折光を反射する基
準反射面と、 この基準反射面で反射され、前記被測定光学系および前
記回折格子を介して合成された異なる次数の回折光によ
り形成される干渉縞を、前記回折格子を回転させながら
検出する検出手段と、を備えたことを特徴とする像面測
定装置。1. A measurement light source for irradiating an optical system to be measured with measurement light, a diffraction grating arranged in front of the measurement optical system for diffracting the measurement light emitted from the measurement light source, and a diffraction grating A rotation mechanism that rotates about an axis parallel to the axis, a reference reflection surface that is disposed at the focal position of the measured optical system, and that reflects the diffracted light that has been diffracted by the diffraction grating and transmitted through the measured optical system, An interference fringe reflected by the reference reflection surface and formed by diffracted light of different orders synthesized through the optical system to be measured and the diffraction grating, and detecting means for detecting while rotating the diffraction grating. An image plane measuring device characterized by being provided.
せる回折格子と、 この回折格子で回折された回折光を被測定光学系の被測
定結像面に結像させる基準レンズと、 前記被測定結像面に配置され、前記回折光を反射する基
準反射面と、 前記回折格子を前記基準レンズの光軸と平行な軸を中心
に回転させる回転機構と、 前記基準反射面で反射され、前記基準光学系および前記
回折格子を介して合成された異なる次数の回折光により
形成される干渉縞を、前記回折格子を回転させながら検
出する検出手段と、を備えたことを特徴とする像面測定
装置。2. A diffraction grating for diffracting the measurement light emitted from the measurement light source, a reference lens for forming an image of the diffracted light diffracted by the diffraction grating on a measured image forming surface of the measured optical system, and A reference reflection surface arranged on the measurement image forming surface, which reflects the diffracted light, a rotation mechanism which rotates the diffraction grating about an axis parallel to the optical axis of the reference lens, and is reflected by the reference reflection surface, An image plane, comprising: a detection unit that detects an interference fringe formed by diffracted light of different orders combined through the reference optical system and the diffraction grating while rotating the diffraction grating. measuring device.
射面は、±１次回折光のみを反射する像面測定装置。3. The image surface measuring device according to claim 1, wherein the reference reflecting surface reflects only ± first-order diffracted light.
準反射面で反射し、さらに前記回折格子で回折した±１
次回折光のみを透過する空間フィルタを備えている像面
測定装置。4. The apparatus according to claim 3, further comprising ± 1 reflected by the reference reflection surface and further diffracted by the diffraction grating.
An image plane measuring device equipped with a spatial filter that transmits only the second-order diffracted light.
段は、前記回折格子を所定角度回転させる間に変化する
前記干渉縞の明暗をカウントする像面測定装置。5. The image plane measuring device according to claim 1, wherein the detecting means counts the contrast of the interference fringes that changes while rotating the diffraction grating by a predetermined angle.
記干渉縞の明暗数から像面の傾き量を検出する像面測定
装置。6. The image plane measuring device according to claim 5, wherein the detecting means detects the amount of inclination of the image plane from the number of light and shade of the interference fringes.
記干渉縞の明暗の周期が最も長くなるときの前記回転格
子の基準位置からの回転角を検出して像面の倒れ方向を
検出する像面測定装置。7. The detecting means according to claim 5, wherein the detecting means detects a rotation angle from the reference position of the rotary grating when the light-dark cycle of the interference fringes is the longest, and detects the tilt direction of the image plane. Image plane measuring device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06292194A JP3315805B2 (en) | 1993-03-31 | 1994-03-31 | Image plane measuring device |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7355893 | 1993-03-31 | ||
| JP5-73558 | 1993-03-31 | ||
| JP06292194A JP3315805B2 (en) | 1993-03-31 | 1994-03-31 | Image plane measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06337235A true JPH06337235A (en) | 1994-12-06 |
| JP3315805B2 JP3315805B2 (en) | 2002-08-19 |
Family
ID=26403980
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06292194A Expired - Fee Related JP3315805B2 (en) | 1993-03-31 | 1994-03-31 | Image plane measuring device |
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| Country | Link |
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| JP (1) | JP3315805B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100398666B1 (en) * | 1994-11-07 | 2003-12-11 | 지고 코포레이션 | Surface contouring method and diffractometer using diffractive optical device |
| CN112840188A (en) * | 2018-10-12 | 2021-05-25 | 英弘精机株式会社 | Laser radar for meteorological observation |
-
1994
- 1994-03-31 JP JP06292194A patent/JP3315805B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100398666B1 (en) * | 1994-11-07 | 2003-12-11 | 지고 코포레이션 | Surface contouring method and diffractometer using diffractive optical device |
| CN112840188A (en) * | 2018-10-12 | 2021-05-25 | 英弘精机株式会社 | Laser radar for meteorological observation |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3315805B2 (en) | 2002-08-19 |
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