JP2010139463A - Method of measuring sphericity of sphere, and method of measuring curvature radius of sphere - Google Patents

Method of measuring sphericity of sphere, and method of measuring curvature radius of sphere Download PDF

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JP2010139463A
JP2010139463A JP2008318066A JP2008318066A JP2010139463A JP 2010139463 A JP2010139463 A JP 2010139463A JP 2008318066 A JP2008318066 A JP 2008318066A JP 2008318066 A JP2008318066 A JP 2008318066A JP 2010139463 A JP2010139463 A JP 2010139463A
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JP5188377B2 (en
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Masayuki Nara
正之 奈良
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Mitutoyo Corp
Mitsutoyo Kiko Co Ltd
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Mitsutoyo Kiko Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To achieve a method of measuring sphericity of a sphere and a method of measuring a curvature radius of a sphere, by which a better measurement of a surface shape of an optically transparent sphere can be performed. <P>SOLUTION: An interference band is created wherein a first reflected light R1 on the upper surface of an optically transparent sphere 10 and a second reflected light R2 on the lower surface of the sphere 10 are interfered. Using for example an interferometer 100 to which a Fizeau type interferometer is applied, distribution of an optical path difference between the upper surface and the lower surface of the sphere 10 can be calculated based on the interference band, and sphericity of the phere 10 can be calculated based on the optical path difference. In addition, when the first reflected light R1 is interfered with the second reflected light R2 to generate the interference band, by detecting a first arrangement wherein the focus of a light irradiated from a light source 1 becomes a center of the sphere 10 and a second arrangement wherein the focus of a light irradiated from a light source 1 becomes a surface of the sphere 10, a curvature radius of the sphere 10 can be calculated based on an amount of moving from the first arrangement to the second arrangement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、球体の真球度の測定方法および球体の曲率半径の測定方法に係り、特に、光学的に透明な球体の真球度および曲率半径の測定方法に関する。   The present invention relates to a method for measuring the sphericity of a sphere and a method for measuring a radius of curvature of a sphere, and more particularly to a method of measuring the sphericity and radius of curvature of an optically transparent sphere.

従来、可干渉性の光源から出力された光が基準板の参照面で反射された参照光と、その光源からの光が被測定物の測定対象面（被検面）で反射された測定光とを干渉させて生成した干渉縞に基づき、被測定物の表面形状に関する測定を行う技術が知られている（例えば、特許文献１参照。）。
特開２００８−８２７８１号公報 Conventionally, reference light in which light output from a coherent light source is reflected on the reference surface of the reference plate, and measurement light in which light from the light source is reflected on the measurement target surface (test surface) of the object to be measured A technique for measuring the surface shape of the object to be measured based on the interference fringes generated by the interference is known (see, for example, Patent Document 1).
JP 2008-82781 A

しかしながら、上記特許文献１の場合、より正確な測定とするため、好適な干渉縞を生成するように被測定物の位置を調整する作業は煩雑であった。
また、光学的に透明な球体を被測定物とした場合、その透明な球体に光源からの光が照射されると、球体上面側の凸面で反射される反射光と、凸面を透過して球体下面側の凹面で反射される反射光とが生じるので、参照光を合わせると３つの反射光が混在することとなる。 However, in the case of the above-mentioned Patent Document 1, in order to obtain more accurate measurement, the work of adjusting the position of the object to be measured so as to generate a suitable interference fringe is complicated.
In addition, when an optically transparent sphere is used as the object to be measured, when light from the light source is irradiated to the transparent sphere, the reflected light reflected by the convex surface on the upper surface side of the sphere and the sphere passing through the convex surface are transmitted. Since reflected light reflected by the concave surface on the lower surface side is generated, when the reference light is combined, three reflected lights are mixed.

本発明の目的は、光学的に透明な球体の表面形状に関する好適な測定が可能となる、球体の真球度の測定方法および球体の曲率半径の測定方法を提供することである。   An object of the present invention is to provide a method for measuring the sphericity of a sphere and a method for measuring a radius of curvature of the sphere, which allow suitable measurement regarding the surface shape of an optically transparent sphere.

以上の課題を解決するため、請求項１に記載の発明は、球体の真球度の測定方法であって、
光学的に透明な球体の中心に焦点を合わせるように、その球体に向けて所定の光源から光を照射し、
前記球体の前記光源側の上面を参照面とし、前記球体の前記光源と反対側の下面を被検面とするように、前記上面で反射された第一反射光と、前記上面を透過して前記下面で反射された第二反射光とを干渉させ、
前記第一反射光と前記第二反射光とが干渉することで生成した干渉縞を測定することにより得られる前記第一反射光と前記第二反射光との光路差の分布に基づき、前記球体の真球度を算出することを特徴とする。 In order to solve the above problems, the invention described in claim 1 is a method for measuring the sphericity of a sphere,
In order to focus on the center of an optically transparent sphere, light is emitted from a predetermined light source toward the sphere,
The first reflected light reflected by the upper surface and the upper surface are transmitted so that the upper surface on the light source side of the sphere is a reference surface and the lower surface opposite to the light source of the sphere is a test surface. Interfering with the second reflected light reflected by the lower surface,
Based on the distribution of the optical path difference between the first reflected light and the second reflected light obtained by measuring the interference fringes generated by the interference between the first reflected light and the second reflected light, the sphere The sphericity of is calculated.

請求項２に記載の発明は、球体の曲率半径の測定方法であって、
光学的に透明な球体の中心に焦点を合わせるように、その球体に向けて所定の光源から光を照射し、
前記球体の前記光源側の上面を参照面とし、前記球体の前記光源と反対側の下面を被検面とするように、前記上面で反射された第一反射光と、前記上面を透過して前記下面で反射された第二反射光とが干渉して干渉縞が生成される際に、前記球体が位置する第一配置を測定し、
次いで、前記球体を前記光源から光軸に沿って離間させて前記球体の前記参照面に焦点が合った際に、前記球体が位置する第二配置を測定し、
前記第一配置から前記第二配置までの移動量に基づき、前記球体の曲率半径を算出することを特徴とする。 The invention according to claim 2 is a method of measuring a radius of curvature of a sphere,
In order to focus on the center of an optically transparent sphere, light is emitted from a predetermined light source toward the sphere,
The first reflected light reflected by the upper surface and the upper surface are transmitted so that the upper surface on the light source side of the sphere is a reference surface and the lower surface opposite to the light source of the sphere is a test surface. When the interference pattern is generated by interference with the second reflected light reflected by the lower surface, the first arrangement where the sphere is located is measured,
Next, when the sphere is separated from the light source along the optical axis and the reference surface of the sphere is focused, a second arrangement where the sphere is located is measured.
The radius of curvature of the sphere is calculated based on the amount of movement from the first arrangement to the second arrangement.

本発明によれば、球体の真球度の測定方法において、光学的に透明な球体の上面を参照面とし、球体の下面を被検面とすることで、上面（参照面）での第一反射光と、下面（被検面）での第二反射光とが干渉した干渉縞を生成させて、例えば、フィゾー型干渉計を応用した干渉計を用いて、それら反射光による干渉縞を測定することにより球体の上面と下面との間の光路差の分布を算出することができ、その光路差分布に基づいて球体の真球度を算出することができる。特に、干渉計における干渉縞の生成に伴う反射光の到達を指標とすることによって、球体に向けて照射する光の焦点を球体の中心に合わせる作業を比較的容易に行うことができるので、その干渉縞の測定を容易に行うことが可能となり、好適に球体の真球度の測定を行うことができる。
また、球体の曲率半径の測定方法において、光学的に透明な球体の上面を参照面とし、球体の下面を被検面とすることで、例えば、フィゾー型干渉計を応用した干渉計を用いて、光源から照射された光の焦点が球体の中心となって第一反射光と第二反射光とにより干渉縞が生成される球体の第一配置と、光源から照射された光の焦点が球体の上面（参照面）となる球体の第二配置を容易に検出することができ、その第一配置から第二配置までの移動量に基づいて、球体の曲率半径を好適に測定することができる。 According to the present invention, in the method for measuring the sphericity of a sphere, the upper surface of the optically transparent sphere is used as a reference surface, and the lower surface of the sphere is used as a test surface. Generate interference fringes in which the reflected light interferes with the second reflected light on the lower surface (test surface) and measure the interference fringes due to the reflected light using, for example, an interferometer applying a Fizeau interferometer Thus, the distribution of the optical path difference between the upper surface and the lower surface of the sphere can be calculated, and the sphericity of the sphere can be calculated based on the optical path difference distribution. In particular, by using the arrival of reflected light accompanying the generation of interference fringes in the interferometer as an index, the work of focusing the light irradiating the sphere on the center of the sphere can be performed relatively easily. The interference fringes can be easily measured, and the sphericity of the sphere can be preferably measured.
In the method of measuring the radius of curvature of the sphere, the upper surface of the optically transparent sphere is used as a reference surface, and the lower surface of the sphere is used as a test surface. For example, an interferometer using a Fizeau interferometer is used. The first arrangement of spheres in which interference fringes are generated by the first reflected light and the second reflected light, with the focal point of the light emitted from the light source being the center of the sphere, and the focal point of the light emitted from the light source is the sphere The second arrangement of the sphere serving as the upper surface (reference surface) of the sphere can be easily detected, and the radius of curvature of the sphere can be suitably measured based on the amount of movement from the first arrangement to the second arrangement. .

以下、本発明の実施形態たる球体の真球度の測定方法および球体の曲率半径の測定方法について図面を参照して説明する。
本発明において、光学的に透明な球体に対する測定を実施するにあたり、フィゾー型の干渉計を応用した干渉計１００を用いる。 Hereinafter, a method for measuring the sphericity of a sphere and a method for measuring a radius of curvature of the sphere according to an embodiment of the present invention will be described with reference to the drawings.
In the present invention, an interferometer 100 to which a Fizeau interferometer is applied is used for measurement on an optically transparent sphere.

干渉計１００は、図１に示すように、光源１と、コリメータレンズ２と、ビームスプリッタ３と、対物レンズ４と、結像レンズ５と、撮像素子６、制御部７等を備えている。   As shown in FIG. 1, the interferometer 100 includes a light source 1, a collimator lens 2, a beam splitter 3, an objective lens 4, an imaging lens 5, an image sensor 6, a control unit 7, and the like.

光源１は、例えば、可干渉性に優れたレーザ光を出力するレーザ光源である。   The light source 1 is, for example, a laser light source that outputs laser light having excellent coherence.

コリメータレンズ２は、ビームスプリッタ３の前面側と光源１との間に配されており、光源１から出力された光を平行光に変換し、ビームスプリッタ３の前面に向けて入射させる。   The collimator lens 2 is disposed between the front side of the beam splitter 3 and the light source 1, converts the light output from the light source 1 into parallel light, and enters the light toward the front surface of the beam splitter 3.

ビームスプリッタ３は、前面側から入射された光を、後面側に透過させて出射させる。
また、ビームスプリッタ３は、後面側から入射された光の光路を９０°曲げて、光出射側面から出射させる。 The beam splitter 3 transmits the light incident from the front side to the rear side and emits it.
Further, the beam splitter 3 bends the optical path of the light incident from the rear surface side by 90 ° and emits the light from the light emitting side surface.

対物レンズ４は、ビームスプリッタ３の後面側と被測定物を載置する載置台９との間に配されており、ビームスプリッタ３の後面側から出射された光を被測定物（球体１０）に向けて集光する。
また、対物レンズ４は、被測定物（球体１０）で反射された反射光を、ビームスプリッタ３の後面に向けて入射させる。 The objective lens 4 is disposed between the rear surface side of the beam splitter 3 and the mounting table 9 on which the object to be measured is placed, and the light emitted from the rear surface side of the beam splitter 3 is measured with the object to be measured (sphere 10). Condensed toward.
The objective lens 4 causes the reflected light reflected by the object to be measured (the sphere 10) to enter the rear surface of the beam splitter 3.

結像レンズ５は、ビームスプリッタ３の光出射側面と撮像素子６との間に配されており、ビームスプリッタ３の光出射側面から出射された光を撮像素子６へ導く。
なお、結像レンズ５と撮像素子６の間に、絞り板８が配されている。 The imaging lens 5 is disposed between the light output side surface of the beam splitter 3 and the image sensor 6, and guides light emitted from the light output side surface of the beam splitter 3 to the image sensor 6.
A diaphragm plate 8 is disposed between the imaging lens 5 and the image sensor 6.

撮像素子６は、例えば、ＣＣＤ（Charge Coupled Device）であり、参照面で反射された第一反射光と、被検面で反射された第二反射光とを干渉させて生成した干渉縞の撮像を行う。
また、撮像素子６は、撮像した干渉縞に関するデータ（例えば、干渉縞の画像データ）を、制御部７に出力する。 The imaging device 6 is, for example, a CCD (Charge Coupled Device), and captures interference fringes generated by causing interference between the first reflected light reflected by the reference surface and the second reflected light reflected by the test surface. I do.
Further, the image sensor 6 outputs data regarding the captured interference fringes (for example, image data of the interference fringes) to the control unit 7.

制御部７は、入力された干渉縞に関するデータに基づき、所定の測定処理を実行する。
例えば、制御部７は、干渉縞に関するデータに基づいて、第一反射光と第二反射光との光路差の分布を算出する。また、制御部７は、算出した光路差の分布に基づき、例えば、球体の真球度を算出する。
また、制御部７は、反射光の測定を行った被測定物としての球体の配置に基づき、球体の曲率半径を算出する。 The control unit 7 performs a predetermined measurement process based on the input data regarding interference fringes.
For example, the control unit 7 calculates the distribution of the optical path difference between the first reflected light and the second reflected light based on the data regarding the interference fringes. Further, the control unit 7 calculates, for example, the sphericity of the sphere based on the calculated distribution of optical path differences.
Moreover, the control part 7 calculates the curvature radius of a sphere based on the arrangement | positioning of the sphere as a to-be-measured object which measured the reflected light.

次に、本発明に係る球体の真球度の測定方法について説明する。   Next, a method for measuring the sphericity of a sphere according to the present invention will be described.

図１に示すように、干渉計１００における所定の載置位置（載置台９）に、被測定物である光学的に透明な球体１０を載置する。なお、載置台９に載置された球体１０は、図示しない駆動部によって、光軸に沿った方向や、光軸と交差する方向に移動可能に備えられている。   As shown in FIG. 1, an optically transparent sphere 10 as an object to be measured is placed on a predetermined placement position (mounting table 9) in the interferometer 100. The spherical body 10 placed on the placing table 9 is provided so as to be movable in a direction along the optical axis or a direction intersecting the optical axis by a driving unit (not shown).

次いで、光源１から球体１０に向けて光を照射し、球体１０の中心Ｏに焦点を合わせるように、その球体１０の位置（球体１０が載置された載置台９の位置）を調整する。
ここで、光源１から照射された光の焦点が球体１０の中心Ｏに合った場合、球体１０の光源１側の上面を参照面１１とし、球体１０の光源１と反対側の下面を被検面１２とすると、図２に示すように、入射光が参照面１１で反射された第一反射光Ｒ１と、入射光が参照面１１を透過し被検面１２で反射された第二反射光Ｒ２とが生じる。
そして、第一反射光Ｒ１と第二反射光Ｒ２は、それぞれ入射光の経路をたどるように戻り、対物レンズ４、ビームスプリッタ３、結像レンズ５を通じて、撮像素子６へと導かれる。ただし、第二反射光Ｒ２は第一反射光Ｒ１より、球体１０の中心Ｏを通過する一往復分（参照面１１と被検面１２の間の一往復分）、長い光路を有している。 Next, light is emitted from the light source 1 toward the sphere 10 and the position of the sphere 10 (the position of the mounting table 9 on which the sphere 10 is mounted) is adjusted so as to focus on the center O of the sphere 10.
Here, when the light emitted from the light source 1 is focused on the center O of the sphere 10, the upper surface of the sphere 10 on the light source 1 side is used as the reference surface 11, and the lower surface of the sphere 10 opposite to the light source 1 is tested. As shown in FIG. 2, as shown in FIG. 2, as shown in FIG. 2, first reflected light R <b> 1 in which incident light is reflected by the reference surface 11, and second reflected light in which incident light passes through the reference surface 11 and is reflected by the test surface 12. R2 is generated.
Then, the first reflected light R1 and the second reflected light R2 return to follow the path of the incident light, respectively, and are guided to the image sensor 6 through the objective lens 4, the beam splitter 3, and the imaging lens 5. However, the second reflected light R2 has a longer optical path than the first reflected light R1 by one reciprocation passing through the center O of the sphere 10 (one reciprocation between the reference surface 11 and the test surface 12). .

こうして、球体１０における参照面１１と被検面１２の間の一往復分の光路長が異なる第一反射光Ｒ１と第二反射光Ｒ２が同じ経路を通って撮像素子６に導かれるため、第一反射光Ｒ１と第二反射光Ｒ２とがその光路長が異なることに伴い干渉することとなり、撮像素子６において干渉縞が検出されて測定される。   Thus, the first reflected light R1 and the second reflected light R2 having different optical path lengths for one round trip between the reference surface 11 and the test surface 12 in the sphere 10 are guided to the image sensor 6 through the same path. The first reflected light R1 and the second reflected light R2 interfere with each other as their optical path lengths differ, and interference fringes are detected and measured by the image sensor 6.

なお、図３に示すように、光源１から照射された光の焦点が球体１０の中心Ｏに合わない場合、反射光が入射光の経路をたどって戻ることができないので、反射光が撮像素子６へ導かれない。
つまり、球体１０の中心Ｏに焦点を合わせることで、撮像素子６に反射光が到達することとなるので、撮像素子６への反射光の到達を指標とすることによって、球体１０の中心Ｏに焦点を合わせる作業（球体１０の位置調節作業）を比較的容易に行うことが可能になっている。 As shown in FIG. 3, when the light emitted from the light source 1 is not focused on the center O of the sphere 10, the reflected light cannot return along the path of the incident light. Not led to 6.
That is, since the reflected light reaches the image sensor 6 by focusing on the center O of the sphere 10, the arrival of the reflected light to the image sensor 6 is used as an index to reach the center O of the sphere 10. The operation of adjusting the focus (the operation of adjusting the position of the sphere 10) can be performed relatively easily.

次いで、撮像素子６で測定された干渉縞に基づき、制御部７が、測定された範囲中の各点での、参照面１１と被検面１２との間の光路差の分布を算出する（後述する式（１）参照）。
例えば、制御部７は、干渉縞の画像データに対してフーリエ変換法による処理を施すことで、光の位相（例えば、被検面１２の位相）を求めて、各点での光路差の分布を算出する。つまり、撮像素子６で測定された干渉縞は、球体１０の光学的な直径（球体１０の中心Ｏを通る参照面１１と被検面１２の距離）のばらつきを含んでいるので、この干渉縞から、測定された範囲中の各点における参照面１１と被検面１２との間の光路差の分布を算出することができる。
また、制御部７は、算出した光路差の分布に基づき、球体１０の真球度を算出する（後述する式（２）参照）。 Next, based on the interference fringes measured by the image sensor 6, the control unit 7 calculates the distribution of the optical path difference between the reference surface 11 and the test surface 12 at each point in the measured range ( (See formula (1) below).
For example, the control unit 7 obtains the phase of the light (for example, the phase of the test surface 12) by performing processing by Fourier transform on the image data of the interference fringes, and distributes the optical path difference at each point. Is calculated. That is, the interference fringes measured by the imaging device 6 include variations in the optical diameter of the sphere 10 (the distance between the reference surface 11 passing through the center O of the sphere 10 and the test surface 12). Thus, the distribution of the optical path difference between the reference surface 11 and the test surface 12 at each point in the measured range can be calculated.
Further, the control unit 7 calculates the sphericity of the sphere 10 based on the calculated distribution of optical path differences (see formula (2) described later).

例えば、球体１０の直径をＤ（θ，φ）とし（θ：球の緯度にあたる角度、φ：球の経度にあたる角度）、球体１０内部の屈折率をｎとした場合、干渉縞に基づいて制御部７で計算された光路差の分布ｍ（θ，φ）は、以下の式（１）で表すことができる。   For example, when the diameter of the sphere 10 is D (θ, φ) (θ: an angle corresponding to the latitude of the sphere, φ: an angle corresponding to the longitude of the sphere), and the refractive index inside the sphere 10 is n, the control is performed based on the interference fringes. The optical path difference distribution m (θ, φ) calculated by the unit 7 can be expressed by the following equation (1).

Figure 2010139463
Figure 2010139463

また、制御部７は、算出した光路差の分布ｍ（θ，φ）における、ｍ（θ，φ）の最大値と最小値の差をとり、光学的な真球度Ｓ０を以下の式（２）により算出する。
Ｓ０＝ｍａｘ（ｍ（θ，φ））−ｍｉｎ（ｍ（θ，φ）） … 式（２） The control unit 7, in the distribution m of the calculated optical path difference (θ, φ), m ( θ, φ) takes the difference between the maximum value and the minimum value of the following formula an optical sphericity S 0 Calculate by (2).
S 0 = max (m (θ, φ)) − min (m (θ, φ)) (2)

また、球体材料の屈折率ｎが既知である場合、光路差の分布ｍ（θ，φ）を屈折率ｎで割ることにより、直径値のばらつきを算出することができる（式（３））。
ＤＡ（θ，φ）＝ｍ（θ，φ）／ｎ … 式（３）
また、球体１０の（実長さでの）真球度Ｓは、以下の式（４）により算出できる。
Ｓ＝ｍａｘ（ＤＡ（θ，φ））−ｍｉｎ（ＤＡ（θ，φ）） …式（４） Also, when the refractive index n of the spherical material is known, the variation in diameter value can be calculated by dividing the optical path difference distribution m (θ, φ) by the refractive index n (Equation (3)).
D A (θ, φ) = m (θ, φ) / n (3)
Further, the sphericity S (in actual length) of the sphere 10 can be calculated by the following equation (4).
S = max (D A (θ, φ)) − min (D A (θ, φ)) (4)

なお、ここで測定された干渉縞は、１回の測定で光が当たった範囲のものであるので、球体１０の全面に亘る測定を行う場合には、球体１０を回転させての複数の測定を行う必要がある。その際、図４に示すように、各測定での測定範囲の一部分が重なるスティッチングを行うようにすることで、球体１０全体の真球度を求めることができる。   In addition, since the interference fringes measured here are those in the range where light hits in one measurement, when performing measurement over the entire surface of the sphere 10, a plurality of measurements by rotating the sphere 10 are performed. Need to do. At that time, as shown in FIG. 4, the sphericity of the entire sphere 10 can be obtained by performing stitching in which a part of the measurement range in each measurement overlaps.

このように、本発明に係る球体の真球度の測定方法によれば、光学的に透明な球体１０の上面を参照面１１とし、球体１０の下面を被検面１２とすることで、フィゾー型干渉計を応用した干渉計１００を用いて、参照面１１と被検面１２との間の光路差の分布を算出することができ、その光路差分布に基づいて球体１０の真球度を算出することができる。
特に、干渉計１００における撮像素子６への反射光の到達を指標とすることによって、球体１０に向けて照射する光の焦点を球体１０の中心Ｏに合わせる作業を比較的容易に行うことができるので、撮像素子６による干渉縞の測定を容易に行うことが可能となり、好適に球体１０の真球度の測定を行うことができる。 As described above, according to the method for measuring the sphericity of a sphere according to the present invention, the upper surface of the optically transparent sphere 10 is used as the reference surface 11 and the lower surface of the sphere 10 is used as the test surface 12. The optical path difference distribution between the reference surface 11 and the test surface 12 can be calculated by using the interferometer 100 to which the interferometer is applied, and the sphericity of the sphere 10 can be calculated based on the optical path difference distribution. Can be calculated.
In particular, by using the arrival of reflected light to the image sensor 6 in the interferometer 100 as an index, the work of focusing the light irradiated toward the sphere 10 on the center O of the sphere 10 can be performed relatively easily. Therefore, it is possible to easily measure the interference fringes by the image pickup device 6 and preferably measure the sphericity of the sphere 10.

次に、本発明に係る球体の曲率半径の測定方法について説明する。   Next, a method for measuring the radius of curvature of the sphere according to the present invention will be described.

図５に示すように、干渉計１００における載置台９に、光学的に透明な球体１０を載置する。
次いで、その球体１０に向けて光源１から光を照射し、載置台９の位置を調整することで、球体１０の中心Ｏに焦点を合わせる（図中、左側の状態）。この球体１０の中心Ｏに光の焦点があった状態で、第一反射光Ｒ１と第二反射光Ｒ２とにより干渉縞が生成されるので、撮像素子６において干渉縞が検出される。なお、前述したように、球体１０に向けて照射する光の焦点を球体１０の中心Ｏに合わせる作業は、撮像素子６への反射光の到達（具体的には、反射光の到達光量）を指標とすることによって容易に行うことができる。
そして、この球体１０の中心Ｏに焦点が合って、干渉縞が生成した際の球体１０の位置（例えば、球体１０が載置された載置台９の位置であって、光軸方向に沿う位置）を測定し、その位置を第一配置とする。 As shown in FIG. 5, an optically transparent sphere 10 is mounted on the mounting table 9 in the interferometer 100.
Next, light is emitted from the light source 1 toward the sphere 10 and the position of the mounting table 9 is adjusted, thereby focusing on the center O of the sphere 10 (state on the left side in the figure). Since the interference fringes are generated by the first reflected light R1 and the second reflected light R2 in a state where the light is focused on the center O of the sphere 10, the interference fringes are detected by the image sensor 6. Note that, as described above, the operation of focusing the light irradiated toward the sphere 10 on the center O of the sphere 10 involves the arrival of reflected light to the image sensor 6 (specifically, the amount of light reaching the reflected light). This can be done easily by using an index.
The position of the sphere 10 when the interference fringe is generated by focusing on the center O of the sphere 10 (for example, the position of the mounting table 9 on which the sphere 10 is mounted and the position along the optical axis direction). ) Is measured and the position is set as the first arrangement.

次いで、球体１０を、光源１から光軸（例えば、対物レンズ４における光軸）に沿った方向に離間させるように、載置台９を移動させる。なお、球体１０が光源１から離間するように移動すると、光源１から照射された光の焦点が球体１０の中心Ｏからずれるので、反射光が撮像素子６にほとんど導かれなくなる。
そして、球体１０の上面である参照面１１に光の焦点が合うまで移動させる（図中、右側の状態）。なお、この球体１０表面の参照面１１に光の焦点が合うと、その反射光が撮像素子６に届くようになり、その反射光を検出可能になる。つまり、撮像素子６への反射光の到達を指標とすることによって、球体１０の参照面１１に焦点を合わせる作業を比較的容易に行うことができる。
この球体１０の参照面１１に焦点が合って、撮像素子６が反射光を検出した際の球体１０の位置（例えば、球体１０が載置された載置台９の位置）を測定し、その位置を第二配置とする。 Next, the mounting table 9 is moved so that the sphere 10 is separated from the light source 1 in the direction along the optical axis (for example, the optical axis of the objective lens 4). Note that when the sphere 10 moves away from the light source 1, the focus of the light emitted from the light source 1 is shifted from the center O of the sphere 10, so that the reflected light is hardly guided to the image sensor 6.
Then, the light is moved until the light is focused on the reference surface 11 which is the upper surface of the sphere 10 (right state in the figure). When the light is focused on the reference surface 11 on the surface of the sphere 10, the reflected light reaches the image sensor 6, and the reflected light can be detected. That is, by using the arrival of the reflected light to the image sensor 6 as an index, the work of focusing on the reference surface 11 of the sphere 10 can be performed relatively easily.
The position of the sphere 10 (for example, the position of the mounting table 9 on which the sphere 10 is mounted) is measured when the imaging device 6 detects the reflected light while focusing on the reference surface 11 of the sphere 10, and the position Is the second arrangement.

次いで、球体１０（載置台９）の第一配置から第二配置までの移動量を求め、その移動量に基づき、制御部７が球体１０の曲率半径Ｃｒを算出する。
なお、本実施形態の場合、光源１から照射された光の焦点が、球体１０の中心Ｏから球体１０の表面（参照面１１）まで移動するように、球体１０（載置台９）が移動されているので、その移動量は球体１０の半径に相当しており、この第一配置から第二配置までの移動量Ｃｒが、曲率半径「Ｃｒ」として測定される。 Next, the movement amount from the first arrangement to the second arrangement of the sphere 10 (mounting table 9) is obtained, and the control unit 7 calculates the curvature radius Cr of the sphere 10 based on the movement amount.
In the case of this embodiment, the sphere 10 (mounting table 9) is moved so that the focal point of the light emitted from the light source 1 moves from the center O of the sphere 10 to the surface (reference surface 11) of the sphere 10. Therefore, the movement amount corresponds to the radius of the sphere 10, and the movement amount Cr from the first arrangement to the second arrangement is measured as the curvature radius “Cr”.

このように、本発明に係る球体の曲率半径の測定方法によれば、光学的に透明な球体１０の上面を参照面１１とし、球体１０の下面を被検面１２とすることで、フィゾー型干渉計を応用した干渉計１００を用いて、光源１から照射された光の焦点が球体１０の中心Ｏとなる球体１０の第一配置と、光源１から照射された光の焦点が球体１０の表面（参照面１１）となる球体１０の第二配置を容易に検出することができ、その第一配置から第二配置までの移動量に基づいて、球体１０の曲率半径を測定することができる。
特に、干渉計１００における撮像素子６への反射光の到達を指標とすることによって、第一配置と第二配置とを容易に検出することができるので、球体１０の半径に相当する第一配置から第二配置までの移動量の測定を容易に行うことが可能となり、好適に球体１０の曲率半径の測定を行うことができる。 As described above, according to the method for measuring the radius of curvature of the sphere according to the present invention, the upper surface of the optically transparent sphere 10 is used as the reference surface 11, and the lower surface of the sphere 10 is used as the test surface 12. Using the interferometer 100 to which the interferometer is applied, the first arrangement of the sphere 10 in which the focus of the light emitted from the light source 1 is the center O of the sphere 10 and the focus of the light emitted from the light source 1 is the sphere 10. The second arrangement of the sphere 10 serving as the surface (reference surface 11) can be easily detected, and the radius of curvature of the sphere 10 can be measured based on the amount of movement from the first arrangement to the second arrangement. .
In particular, since the first arrangement and the second arrangement can be easily detected by using the arrival of reflected light to the image sensor 6 in the interferometer 100 as an index, the first arrangement corresponding to the radius of the sphere 10 is used. It is possible to easily measure the amount of movement from the first to the second arrangement, and it is possible to suitably measure the radius of curvature of the sphere 10.

なお、以上の実施の形態において、曲率半径のみを測定する場合、撮像素子６で反射光の光量ピークの検出を行えれば曲率半径の測定が可能となるので、撮像素子６にＣＣＤを用いる必要はなく、例えば、より安価な半導体光電変換素子等を用いてもよい。なお、この構成の場合、球体の上面での反射がなされればよいので、球体が透明である必要もない。   In the above embodiment, when only the radius of curvature is measured, it is possible to measure the radius of curvature if the image sensor 6 can detect the light intensity peak of the reflected light. Therefore, it is necessary to use a CCD for the image sensor 6. For example, a cheaper semiconductor photoelectric conversion element or the like may be used. In the case of this configuration, the sphere need not be transparent because it only needs to be reflected from the top surface of the sphere.

また、以上の実施の形態における球体の曲率半径の測定方法において、球体１０（載置台９）の移動量に基づき、球体の曲率半径を測定したが、本発明はこれに限定されるものではなく、例えば、対物レンズ４を移動させることで焦点を移動させるようにして、その対物レンズ４の移動量に基づいて球体の曲率半径を測定してもよい。   In the method for measuring the radius of curvature of the sphere in the above embodiment, the radius of curvature of the sphere is measured based on the amount of movement of the sphere 10 (mounting table 9). However, the present invention is not limited to this. For example, the focal point may be moved by moving the objective lens 4, and the radius of curvature of the sphere may be measured based on the amount of movement of the objective lens 4.

また、その他、具体的な細部構造等についても適宜に変更可能であることは勿論である。   In addition, it is needless to say that other specific detailed structures can be appropriately changed.

本実施形態における干渉計と、その干渉計を用いた球体の真球度の測定方法を示す説明図である。It is explanatory drawing which shows the interferometer in this embodiment, and the measuring method of the sphericity of the spherical body using the interferometer. 図１における球体部分の拡大図である。It is an enlarged view of the spherical part in FIG. 対物レンズが集光した光の焦点が球体の中心に合わない状態を示す説明図である。It is explanatory drawing which shows the state which the focus of the light which the objective lens condensed does not match the center of a sphere. 球体の真球度の測定方法におけるスティッチングに関する説明図である。It is explanatory drawing regarding the stitching in the measuring method of the sphericity of a sphere. 本実施形態における干渉計を用いた球体の曲率半径の測定方法を示す説明図である。It is explanatory drawing which shows the measuring method of the curvature radius of the sphere using the interferometer in this embodiment.

符号の説明Explanation of symbols

１ 光源
２ コリメータレンズ
３ ビームスプリッタ
４ 対物レンズ
５ 結像レンズ
６ 撮像素子
７ 制御部
８ 絞り板
９ 載置台
１０ 球体
１１ 参照面（上面）
１２ 被検面（下面）
１００ 干渉計
Ｏ 中心（球体の中心）
Ｒ１ 第一反射光
Ｒ２ 第二反射光
Ｃｒ 曲率半径（移動量） DESCRIPTION OF SYMBOLS 1 Light source 2 Collimator lens 3 Beam splitter 4 Objective lens 5 Imaging lens 6 Image pick-up element 7 Control part 8 Diaphragm plate 9 Mounting base 10 Sphere 11 Reference surface (upper surface)
12 Test surface (bottom surface)
100 Interferometer O Center (sphere center)
R1 First reflected light R2 Second reflected light Cr Curvature radius (movement amount)

Claims (2)

光学的に透明な球体の中心に焦点を合わせるように、その球体に向けて所定の光源から光を照射し、
前記球体の前記光源側の上面で反射された第一反射光と、前記上面を透過し前記球体の前記光源と反対側の下面で反射された第二反射光とを干渉させ、
前記第一反射光と前記第二反射光とが干渉することで生成した干渉縞を測定することにより得られる前記第一反射光と前記第二反射光との光路差に基づき、前記球体の真球度を算出することを特徴とする球体の真球度の測定方法。 In order to focus on the center of an optically transparent sphere, light is emitted from a predetermined light source toward the sphere,
The first reflected light reflected by the upper surface of the sphere on the light source side and the second reflected light transmitted through the upper surface and reflected by the lower surface of the sphere opposite to the light source;
Based on the optical path difference between the first reflected light and the second reflected light obtained by measuring the interference fringes generated by the interference between the first reflected light and the second reflected light, the trueness of the sphere is determined. A method for measuring the sphericity of a sphere, wherein the sphericity is calculated. 光学的に透明な球体の中心に焦点を合わせるように、その球体に向けて所定の光源から光を照射し、
前記球体の前記光源側の上面で反射された第一反射光と、前記上面を透過し前記球体の前記光源と反対側の下面で反射された第二反射光とが干渉して干渉縞が生成される際に、前記球体が位置する第一配置を測定し、
次いで、前記球体を前記光源から光軸に沿って離間させて前記球体の前記上面に焦点が合った際に、前記球体が位置する第二配置を測定し、
前記第一配置から前記第二配置までの移動量に基づき、前記球体の曲率半径を算出することを特徴とする球体の曲率半径の測定方法。 In order to focus on the center of an optically transparent sphere, light is emitted from a predetermined light source toward the sphere,
The first reflected light reflected from the upper surface of the sphere on the light source side and the second reflected light transmitted through the upper surface and reflected from the lower surface opposite to the light source of the sphere interfere to generate interference fringes. Measuring the first arrangement where the sphere is located,
Then, when the sphere is separated from the light source along the optical axis and the upper surface of the sphere is focused, a second arrangement where the sphere is located is measured.
A method for measuring a radius of curvature of a sphere, wherein the radius of curvature of the sphere is calculated based on a movement amount from the first arrangement to the second arrangement.
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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930729A (en) * 1973-06-29 1976-01-06 International Business Machines Corporation Interferometer apparatus incorporating a spherical element of index of refraction of two
JPS63284445A (en) * 1987-05-18 1988-11-21 Hitachi Ltd Method for evaluating spherical microlens
JPH03188302A (en) * 1989-12-18 1991-08-16 Topcon Corp Method and apparatus for measuring surface shape
JPH05196440A (en) * 1991-08-02 1993-08-06 Hughes Aircraft Co Interference ball bearing testing device
JPH08233549A (en) * 1995-02-24 1996-09-13 Nikon Corp Interference measuring system
JPH1090113A (en) * 1996-09-18 1998-04-10 Sony Corp Interferometer
JP2001091227A (en) * 1999-07-22 2001-04-06 Nikon Corp Measuring device for lens and measuring method for lens
JP2002195814A (en) * 2000-12-26 2002-07-10 Hoya Corp Device and method for measuring curvature radius of spherical surface
JP2002214076A (en) * 2001-01-12 2002-07-31 Nikon Corp Interference measuring system, method for measuring transmission wave front and projection lens
JP2005509874A (en) * 2001-11-15 2005-04-14 ザイゴ コーポレイション High-speed in-situ acquisition of aspheric Fizeau
US6917421B1 (en) * 2001-10-12 2005-07-12 Kla-Tencor Technologies Corp. Systems and methods for multi-dimensional inspection and/or metrology of a specimen

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930729A (en) * 1973-06-29 1976-01-06 International Business Machines Corporation Interferometer apparatus incorporating a spherical element of index of refraction of two
JPS63284445A (en) * 1987-05-18 1988-11-21 Hitachi Ltd Method for evaluating spherical microlens
JPH03188302A (en) * 1989-12-18 1991-08-16 Topcon Corp Method and apparatus for measuring surface shape
JPH05196440A (en) * 1991-08-02 1993-08-06 Hughes Aircraft Co Interference ball bearing testing device
JPH08233549A (en) * 1995-02-24 1996-09-13 Nikon Corp Interference measuring system
JPH1090113A (en) * 1996-09-18 1998-04-10 Sony Corp Interferometer
JP2001091227A (en) * 1999-07-22 2001-04-06 Nikon Corp Measuring device for lens and measuring method for lens
JP2002195814A (en) * 2000-12-26 2002-07-10 Hoya Corp Device and method for measuring curvature radius of spherical surface
JP2002214076A (en) * 2001-01-12 2002-07-31 Nikon Corp Interference measuring system, method for measuring transmission wave front and projection lens
US6917421B1 (en) * 2001-10-12 2005-07-12 Kla-Tencor Technologies Corp. Systems and methods for multi-dimensional inspection and/or metrology of a specimen
JP2005509874A (en) * 2001-11-15 2005-04-14 ザイゴ コーポレイション High-speed in-situ acquisition of aspheric Fizeau

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