JP2007093288A - Light measuring instrument and light measuring method - Google Patents

Light measuring instrument and light measuring method Download PDF

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JP2007093288A
JP2007093288A JP2005280363A JP2005280363A JP2007093288A JP 2007093288 A JP2007093288 A JP 2007093288A JP 2005280363 A JP2005280363 A JP 2005280363A JP 2005280363 A JP2005280363 A JP 2005280363A JP 2007093288 A JP2007093288 A JP 2007093288A
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light
measurement
coupling element
splitting
reflecting mirror
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Haruhisa Yagi
晴久 八木
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To establish a measuring instrument for simultaneously measuring, through simple adjustment, chromatic aberration, coma aberration, astigmatism, and spherical aberration of an optical component which corresponds to a plurality of wavelengths, using a single device. <P>SOLUTION: This light measuring instrument is equipped with a plurality of light sources different in wavelengths. Rays of light simultaneously outputted from the light sources are divided into reference light and measurement light for each of individual wavelengths, and superimposed on each other by being applied to an object under inspection and to referential movable mirrors 13, 14, and 15. A plurality of interference fringe images different in wavelengths can be thus formed. Wavelength selection filters 16 and 17 are used to classify the formed fringe images by wavelength, which are fetched into a personal computer. Electronic analysis of the taken-in images makes it possible to measure coma aberration, astigmatism, and spherical aberrations. Furthermore, as to chromatic aberration measurement, it is possible to calculate the chromatic aberrations from the amount of deviation of the focal distance of the object by using the measurement light of individual wavelengths. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、干渉計を用いてのカメラ、顕微鏡、望遠鏡、メガネなどの光学機器やＣＤ、ＤＶＤ、ＢＤなどの光記録装置などに用いるレンズ等の光学部品の収差測定、及び、光ファイバーや光導路等の屈折率分布測定や光透過物体及び反射物体の形状計測などの位相測定に用いる干渉像を撮影する光計測装置及び光計測方法に関する。   The present invention relates to aberration measurement of optical parts such as lenses used in optical devices such as cameras, microscopes, telescopes, and glasses using optical interferometers and optical recording devices such as CD, DVD, and BD, optical fibers, and optical paths. The present invention relates to an optical measurement device and an optical measurement method for capturing an interference image used for phase measurement such as refractive index distribution measurement and shape measurement of a light transmission object and a reflection object.

干渉計を用いての光学部品の収差測定や位相測定は一般的に知られており、高精度での測定が可能となっている。収差測定は試料の干渉像を記録する過程と、その像から位相を解析して収差を求める過程に大別される。干渉像を記録する装置としては、レーザ光源とＣＣＤカメラ及びマイケルソンやマッハチェンダなどの干渉計によって構成される。位相解析としては、フーリエ変換法や位相ステップ法などがあり、収差の計算にはゼルニケ公式が用いられる。
マイケルソン干渉計を用いた代表的な干渉像の記録方法を図２に示す。レーザ光源３０１から出た光をビームエキスパンダ３０８により平行光にする。平行光になった光はビームスプリッタ３０２により参照光と計測光に分けられる。参照光は基準ミラー３０３に照射され、計測光は試料３０４を透過して試料後方焦点に置かれた基準ミラー３０５に照射される。ミラー３０５表面上に焦点を結んだ光は反射されて再び試料３０４に入射し、再び平行光となってビームスプリッタ３０２まで戻る。基準ミラー３０３で反射された参照光は往路と同じ光路でビームスプリッタ３０２まで戻る。ビームスプリッタ３０２まで戻った参照光と計測光は再び重ねあわされる。再び重ねあわされた光は計測光と参照光の位相差により干渉縞が生じる。この干渉縞をＣＣＤカメラ３０６で撮影することで干渉縞の記録が可能となる。撮影された干渉像をパソコン３０７に取り込みフーリエ変換法にて位相情報を抽出する。
得られた位相情報からゼルニケ公式を用いると収差を求めることが出来る。また、位相ステップ法を用いるには基準ミラー３０３もしくは基準ミラー３０５のどちらかに高精度移動装置を取り付けることで可能となる。この時、１回の移動につき１枚の画像を撮影して複数の画像をパソコン３０７に取り込み計算すると、位相情報が得られる。この位相情報からゼルニケ公式により収差を求めることができる。しかしながら、この方法は単色光における測定のため特定の波長に対する収差のみしか測定できない。
そこで、代表的な異なった波長に対する色収差の測定方法が提案されている（特許文献１）。図３は複数の光源を用いた色収差測定用撮影部の概略図である。波長の異なった光源４０１、光源４０２、光源４０３から出たそれぞれの光をハーフプリズム４０４、反射プリズム４０５を用いて同一の軸上に重ね、コリメータレンズ４０６により平行光にする。平行光となったそれぞれの光は試料４０７に入射する。入射したそれぞれの光は試料４０７が持つ屈折率により屈折する。屈折量は光の波長により異なるので試料４０７の後方に置かれたレンズ４０８により結像されると、その結像位置が異なる。結像位置が異なった複数の像を受光素子４０９により検出する。複数波長から生じたそれぞれの像位置のずれ量とレンズ４０８の出射角度からの計算で各波長の屈折率を得ることが出来る。この方法により異なる波長に対しての試料が持つ色収差測定が可能となる。
しかし、この技術は収差の一種である色収差しか測定できない。そこで、異なる波長に対しての光透過物体の収差測定に応用できる複数光源を用いた干渉計測技術が提案されている（例えば、特許文献２）。図４は複数の光源を用いた干渉計測用撮影部の概略図である。波長の異なった光源５０１、光源５０２、光源５０３から出たそれぞれの光をビームスプリッタ５０４、ビームスプリッタ５０５を用いて同一の軸上に重ね、コリメータ５０６により平行光にする。平行光になった光はビームスプリッタ５０７により参照光と計測光に分けられる。参照光は基準ミラー５０８に、計測光は試料５０９にそれぞれ照射される。計測光は試料５０９で反射されてビームスプリッタ５０７まで戻る。参照光も基準ミラー５０８で反射されてビームスプリッタ５０７に戻る。ビームスプリッタ５０７まで戻った参照光と計測光は再び重ね合わされる。再び重ね合わされた計測光と参照光は、位相差により干渉縞が生じる。それぞれの波長により計測された干渉縞をビームスプリッタ５１０、ビームスプリッタ５１１によりＣＣＤカメラ５１２、ＣＣＤカメラ５１３、ＣＣＤカメラ５１４にて撮影する。撮影された干渉像を電子計算機５１５に取り込み、先に述べた方法で処理することで収差測定が可能となる。
特開平６−１９４２６４号公報 特開平５−１１３３１６号公報 Aberration measurement and phase measurement of an optical component using an interferometer are generally known, and measurement with high accuracy is possible. Aberration measurement is roughly divided into a process of recording an interference image of a sample and a process of analyzing the phase from the image to obtain an aberration. The apparatus for recording the interference image includes a laser light source, a CCD camera, and an interferometer such as a Michelson or Mach chainer. As phase analysis, there are a Fourier transform method, a phase step method, and the like, and the Zernike formula is used for calculation of aberration.
FIG. 2 shows a typical interference image recording method using a Michelson interferometer. The light emitted from the laser light source 301 is converted into parallel light by the beam expander 308. The light that has become parallel light is divided into reference light and measurement light by a beam splitter 302. The reference light is applied to the reference mirror 303, and the measurement light is transmitted through the sample 304 and applied to the reference mirror 305 placed at the back focal point of the sample. The light focused on the surface of the mirror 305 is reflected and reenters the sample 304, and becomes parallel light again and returns to the beam splitter 302. The reference light reflected by the reference mirror 303 returns to the beam splitter 302 along the same optical path as the forward path. The reference light and the measurement light that have returned to the beam splitter 302 are overlapped again. The light that is superimposed again causes interference fringes due to the phase difference between the measurement light and the reference light. The interference fringes can be recorded by photographing the interference fringes with the CCD camera 306. The captured interference image is taken into the personal computer 307 and phase information is extracted by the Fourier transform method.
Using the Zernike formula from the obtained phase information, the aberration can be obtained. In addition, the phase step method can be used by attaching a high-precision moving device to either the reference mirror 303 or the reference mirror 305. At this time, phase information can be obtained by taking one image per movement and taking a plurality of images into the personal computer 307 for calculation. From this phase information, the aberration can be obtained by the Zernike formula. However, this method can measure only the aberration for a specific wavelength because of the measurement in monochromatic light.
Therefore, a typical method for measuring chromatic aberration with respect to different wavelengths has been proposed (Patent Document 1). FIG. 3 is a schematic view of a chromatic aberration measurement photographing unit using a plurality of light sources. The light emitted from the light sources 401, 402, and 403 having different wavelengths are overlapped on the same axis using the half prism 404 and the reflecting prism 405, and are collimated by the collimator lens 406. Each light that has become parallel light enters the sample 407. Each incident light is refracted by the refractive index of the sample 407. Since the amount of refraction varies depending on the wavelength of light, when the image is formed by the lens 408 placed behind the sample 407, the image formation position differs. A plurality of images with different imaging positions are detected by the light receiving element 409. The refractive index of each wavelength can be obtained by calculating from the shift amount of each image position generated from a plurality of wavelengths and the emission angle of the lens 408. This method makes it possible to measure chromatic aberration of samples with different wavelengths.
However, this technique can only measure chromatic aberration, which is a kind of aberration. Therefore, an interference measurement technique using a plurality of light sources that can be applied to aberration measurement of a light transmitting object for different wavelengths has been proposed (for example, Patent Document 2). FIG. 4 is a schematic diagram of an imaging unit for interference measurement using a plurality of light sources. The light beams emitted from the light sources 501, 502, and 503 having different wavelengths are superimposed on the same axis using the beam splitter 504 and the beam splitter 505, and are collimated by the collimator 506. The light that has become parallel light is divided into reference light and measurement light by a beam splitter 507. The reference light is applied to the reference mirror 508, and the measurement light is applied to the sample 509. The measurement light is reflected by the sample 509 and returns to the beam splitter 507. The reference light is also reflected by the reference mirror 508 and returns to the beam splitter 507. The reference light and measurement light that have returned to the beam splitter 507 are superimposed again. The measurement light and the reference light that are superimposed again cause interference fringes due to the phase difference. The interference fringes measured at the respective wavelengths are photographed by the CCD camera 512, the CCD camera 513, and the CCD camera 514 by the beam splitter 510 and the beam splitter 511. Aberration measurement can be performed by taking the captured interference image into the electronic computer 515 and processing it by the method described above.
JP-A-6-194264 JP-A-5-113316

しかし、屈折率を持つ光透過物体の測定では、それぞれの波長で屈折量が異なるため測定の際には各波長に適応するように干渉計を構成する光学部品の全配置を再調整する必要がある。例えば、位相ステップ法を用いる際には、干渉計を構成する光学部品の移動量を各波長に対して変化させなければならない。また、フーリエ変換法に用いる際には、各波長により縞数が異なるため、高精度測定をする際には各波長において最適な縞数になるように干渉計を構成する光学部品の全配置を再調整する必要がある。よって、試料を装置にセットした後、再調整が必要となり測定に時間がかかる。また、異なる波長に対しての収差を測定するために装置を変えるとその都度セットし再調整が必要となり、非常に手間がかかる。   However, when measuring light-transmitting objects with a refractive index, the amount of refraction differs at each wavelength, so it is necessary to readjust the entire arrangement of the optical components that make up the interferometer to adapt to each wavelength. is there. For example, when the phase step method is used, the movement amount of the optical component constituting the interferometer must be changed with respect to each wavelength. In addition, since the number of fringes differs depending on each wavelength when used in the Fourier transform method, the entire arrangement of the optical components constituting the interferometer is set so that the optimum number of fringes is obtained at each wavelength when performing high-accuracy measurement. Need to readjust. Therefore, after the sample is set in the apparatus, readjustment is necessary and it takes time for measurement. Further, if the apparatus is changed in order to measure aberrations for different wavelengths, it must be set and readjusted each time, which is very laborious.

そこで本発明では、１つの装置で調整が簡便で、異なる波長に対しての光学部品の収差をフーリエ変換法でも位相ステップ法でも計算できる画像を撮影する方法を確立する。   Therefore, the present invention establishes a method for photographing an image that can be easily adjusted with one apparatus and that can calculate aberrations of optical components for different wavelengths by either a Fourier transform method or a phase step method.

請求項１記載の本発明の光計測装置は、可干渉性光を射出する光源と、前記可干渉性光を計測光と参照光に分けるとともに、前記計測光の戻り光と前記参照光の戻り光を重ね合わせて干渉光を形成する光分割結合素子と、前記光分割結合素子により分けられた前記計測光を反射する計測光反射鏡と、前記光分割結合素子により分けられた前記参照光を反射する参照光反射鏡とを備えた光計測装置であって、前記光源として、第１の光源と、前記第１の光源と波長の異なる可干渉性光を射出する第２の光源を設け、前記光分割結合素子として、前記第１の光源の前記可干渉性光を第１の計測光と第１の参照光に分けるとともに前記第１の計測光の戻り光と前記第１の参照光の戻り光を重ね合わせて第１の干渉光を形成する第１の光分割結合素子と、前記第２の光源の前記可干渉性光を第２の計測光と第２の参照光に分けるとともに前記第２の計測光の戻り光と前記第２の参照光の戻り光を重ね合わせて第２の干渉光を形成する第２の光分割結合素子を設け、前記参照光反射鏡として、前記第１の参照光を反射する第１の参照光反射鏡と、前記第２の参照光を反射する第２の参照光反射鏡を設け、前記計測光反射鏡では、前記第１の計測光と前記第２の計測光とを反射させ、前記第１の干渉光は、前記第２の光分割結合素子を透過し、前記第２の光分割結合素子を透過する前記第１の干渉光と、前記第２の光分割結合素子で形成される前記第２の干渉光とを分割する波長選択フィルタを設け、前記波長選択フィルタで分割された前記第１の干渉光と前記第２の干渉光とを個々に検出する光検出手段を設け、前記計測光反射鏡と前記第１の光分割結合素子との間に被検レンズまたは屈折率をもつ被検物体を配置して前記被検レンズまたは前記被検物体の収差を計測することを特徴とする。
請求項２記載の本発明は、請求項１に記載の光計測装置において、前記計測光反射鏡を可動式とし、前記計測光反射鏡と前記第１の光分割結合素子との光学的距離または角度を変更可能な構成としたことを特徴とする。
請求項３記載の本発明は、請求項１に記載の光計測装置において、前記参照光反射鏡を可動式とし、前記参照光反射鏡と前記光分割結合素子との光学的距離または角度を変更可能な構成としたことを特徴とする。
請求項４記載の本発明は、請求項１に記載の光計測装置において、前記第１の光分割結合素子から前記計測光反射鏡までの光学的距離と、前記第１の光分割結合素子から前記第１の参照光反射鏡までの光学的距離を等しくし、前記第２の光分割結合素子から前記計測光反射鏡までの光学的距離と、前記第２の光分割結合素子から前記第２の参照光反射鏡までの光学的距離を等しくしたことを特徴とする。
請求項５記載の本発明は、請求項１に記載の光計測装置において、前記参照光反射鏡と前記光分割結合素子との間に透過フィルタを設けたことを特徴とする。
請求項６記載の本発明は、請求項１に記載の光計測装置において、前記光源としてレーザ光源を用いたことを特徴とする。
請求項７記載の本発明は、請求項１に記載の光計測装置において、前記光分割結合素子としてビームスプリッタを用いたことを特徴とする。
請求項８記載の本発明は、請求項１に記載の光計測装置において、前記光分割結合素子としてハーフミラーを用いたことを特徴とする。
請求項９記載の本発明は、請求項１に記載の光計測装置において、前記光検出手段としてＣＣＤカメラまたはCMOSカメラを用いたことを特徴とする。
請求項１０記載の本発明は、請求項１に記載の光計測装置において、前記光源として、第１の光源及び前記第２の光源と波長の異なる可干渉性光を射出する第３の光源を設け、前記光分割結合素子として、前記第３の光源の前記可干渉性光を第３の計測光と第３の参照光に分けるとともに前記第３の計測光の戻り光と前記第３の参照光の戻り光を重ね合わせて第３の干渉光を形成する第３の光分割結合素子を設け、前記参照光反射鏡として、前記第３の参照光を反射する第３の参照光反射鏡を設け、前記計測光反射鏡では、前記第１の計測光、前記第２の計測光、及び前記第３の計測光を反射させ、前記第１の干渉光は、前記第２の光分割結合素子及び前記第３の光分割結合素子を透過し、前記第２の干渉光は、前記第３の光分割結合素子を透過し、前記第３の光分割結合素子で形成される前記第３の干渉光を、前記第３の光分割結合素子を透過する前記第１の干渉光及び前記第２の干渉光から分割する波長選択フィルタを設けたことを特徴とする。
請求項１１記載の本発明の光計測方法は、請求項１から１０のいずれかに記載の光計測装置を用いた光計測方法であって、前記参照光反射鏡を所定量だけ移動させることで、前記参照光反射鏡と前記光分割結合素子との光学的距離または角度を変化させ、変化させたそれぞれの前記距離における前記干渉光を前記光検出手段によって検出することを特徴とする。 The optical measurement device according to the first aspect of the present invention includes a light source that emits coherent light, the coherent light is divided into measurement light and reference light, and the return light of the measurement light and the return of the reference light. A light splitting and coupling element that forms interference light by superimposing light, a measurement light reflecting mirror that reflects the measurement light divided by the light splitting and coupling element, and the reference light that is split by the light splitting and coupling element. An optical measurement device including a reference light reflecting mirror that reflects, wherein the light source includes a first light source and a second light source that emits coherent light having a wavelength different from that of the first light source, As the light splitting and coupling element, the coherent light of the first light source is divided into first measurement light and first reference light, and return light of the first measurement light and first reference light. First light splitting and coupling element that forms first interference light by superimposing return light The coherent light of the second light source is divided into second measurement light and second reference light, and the return light of the second measurement light and the return light of the second reference light are superimposed. A second light splitting and coupling element that forms second interference light is provided, and the reference light reflecting mirror includes a first reference light reflecting mirror that reflects the first reference light, and the second reference light. A reflecting second reference light reflecting mirror is provided, the measuring light reflecting mirror reflects the first measuring light and the second measuring light, and the first interference light is the second light. Wavelength selection for splitting the first interference light transmitted through the split coupling element and transmitted through the second optical split coupling element and the second interference light formed by the second optical split coupling element A filter is provided to individually detect the first interference light and the second interference light divided by the wavelength selection filter. A detecting means is provided, and a test lens or a test object having a refractive index is disposed between the measurement light reflecting mirror and the first light splitting and coupling element, and aberrations of the test lens or the test object are measured. It is characterized by measuring.
According to a second aspect of the present invention, in the optical measurement device according to the first aspect, the measurement light reflecting mirror is movable, and an optical distance between the measurement light reflecting mirror and the first light splitting and coupling element or The configuration is such that the angle can be changed.
According to a third aspect of the present invention, in the optical measurement apparatus according to the first aspect, the reference light reflecting mirror is movable, and an optical distance or angle between the reference light reflecting mirror and the light splitting and coupling element is changed. It is characterized by having a possible configuration.
According to a fourth aspect of the present invention, there is provided the optical measurement apparatus according to the first aspect, wherein an optical distance from the first optical division coupling element to the measurement light reflecting mirror, and from the first optical division coupling element The optical distance to the first reference light reflecting mirror is made equal, the optical distance from the second light splitting and coupling element to the measuring light reflecting mirror, and the second light splitting and coupling element to the second The optical distance to the reference light reflecting mirror is equalized.
According to a fifth aspect of the present invention, in the optical measurement apparatus according to the first aspect, a transmission filter is provided between the reference light reflecting mirror and the optical division coupling element.
According to a sixth aspect of the present invention, in the optical measurement apparatus according to the first aspect, a laser light source is used as the light source.
According to a seventh aspect of the present invention, in the optical measurement device according to the first aspect, a beam splitter is used as the light splitting and coupling element.
According to an eighth aspect of the present invention, in the optical measurement device according to the first aspect, a half mirror is used as the optical division coupling element.
According to a ninth aspect of the present invention, in the optical measurement device according to the first aspect, a CCD camera or a CMOS camera is used as the light detecting means.
According to a tenth aspect of the present invention, in the optical measurement device according to the first aspect, a third light source that emits coherent light having a wavelength different from that of the first light source and the second light source is used as the light source. Provided as the light splitting and coupling element, the coherent light of the third light source is divided into third measurement light and third reference light, and the return light of the third measurement light and the third reference A third light splitting and coupling element that forms a third interference light by superimposing the return light of the light is provided, and a third reference light reflecting mirror that reflects the third reference light is used as the reference light reflecting mirror. The measurement light reflecting mirror reflects the first measurement light, the second measurement light, and the third measurement light, and the first interference light is reflected by the second light splitting and coupling element. And the third light splitting and coupling element is transmitted, and the second interference light passes through the third light splitting and coupling element. And splitting the third interference light formed by the third light splitting and coupling element from the first interference light and the second interference light transmitted through the third light splitting and coupling element. A wavelength selective filter is provided.
An optical measurement method according to an eleventh aspect of the present invention is an optical measurement method using the optical measurement device according to any one of the first to tenth aspects, wherein the reference light reflecting mirror is moved by a predetermined amount. The optical distance or angle between the reference light reflecting mirror and the light splitting and coupling element is changed, and the interference light at each changed distance is detected by the light detection means.

従来技術のように装置全体の調整が少なく、１つの装置で複数の波長に対する収差をフーリエ変換法でも位相ステップ法でも計算することが可能な画像を撮影することができる。また、フーリエ変換法に用いる画像でヒルベルト変換法にも適用できる。
さらに従来の装置を複数用いるときに発生する試料のセット及び装置全体の再調整などの手間を削減でき、時間を大幅に短縮できる。 There is little adjustment of the entire apparatus as in the prior art, and it is possible to take an image in which aberrations for a plurality of wavelengths can be calculated by a Fourier transform method or a phase step method with one apparatus. Moreover, it is an image used for the Fourier transform method and can also be applied to the Hilbert transform method.
Furthermore, it is possible to reduce the time and labor required for setting a sample and re-adjusting the entire apparatus when using a plurality of conventional apparatuses, and the time can be greatly shortened.

図１は、本発明の最良の形態を示す光計測装置の概略構成図である。
本装置は、複数の波長に対する被検レンズの収差を求めるため画像を撮影するものである。
レーザ１、レーザ２、及びレーザ３は、それぞれ第１の光源、第２の光源、及び第３の光源である。レーザ１の波長をλ１、レーザ２の波長をλ２、レーザ３の波長をλ３とし、それぞれの波長をλ１＜λ２＜λ３とする。
ビームエキスパンダ４、ビームエキスパンダ５、及びビームエキスパンダ６は、それぞれの波長の可干渉性光を平行光にする。 FIG. 1 is a schematic configuration diagram of an optical measuring device showing the best mode of the present invention.
This apparatus captures an image in order to obtain aberrations of the test lens for a plurality of wavelengths.
Laser 1, laser 2, and laser 3 are a first light source, a second light source, and a third light source, respectively. The wavelength of the laser 1 is λ1, the wavelength of the laser 2 is λ2, the wavelength of the laser 3 is λ3, and each wavelength is λ1 <λ2 <λ3.
The beam expander 4, the beam expander 5, and the beam expander 6 make coherent light of each wavelength parallel light.

まずレーザ１の波長λ１は、以下のように測定される。
ピエゾ素子を備えた測定可動ミラー（計測光反射鏡）２４を被検レンズ２５の波長λ１の焦点位置に配置する。レーザ１から出た波長λ１の可干渉性光は、ビームスプリッタ（光分割結合素子）７により参照光と計測光に分けられ、参照光はビームスプリッタ７の１／４の厚さを持ち、同等の屈折率を持つλ１透過フィルタ１０を透過し、ピエゾ素子を備えた基準可動ミラー（参照光反射鏡）１３に照射されて反射し、再びλ１透過フィルタ１０を透過してビームスプリッタ７に戻る。計測光は被検レンズ２５を透過して測定可動ミラー２４上に焦点を結び、反射されて再び被検レンズ２５を透過し、ビームスプリッタ７に戻る。
ビームスプリッタ７では、計測光の戻り光と参照光の戻り光が重ね合わされ、波長λ１の干渉縞が形成される。波長λ１の干渉縞は、ビームスプリッタ８、ビームスプリッタ９、波長選択フィルタ１６、及び波長選択フィルタ１７をそれぞれ順に透過した後に、レンズ１８によってＣＣＤカメラ（光検出手段）２１の画素上に結像される。
ＣＣＤカメラ２１によって撮影した干渉縞画像データはパソコンに取り込んで処理を行う。フーリエ変換法を用いる際には、パソコンに取り込んだ画像データをそのまま処理に用いることができるが、縞の本数が足りない場合には基準可動ミラー１３を傾けることで可能となる。縞数を増やすには計測光と参照光が重なる時の成す角度が大きくなるように基準可動ミラー１３を傾ける。また、縞数を減らしたい時には計測光と参照光が重なる時の成す角度を小さくなるように基準可動ミラー１３を傾ける。計測光と参照光が重なる時の成す角度が0の時、縞数は0本となる。 First, the wavelength λ1 of the laser 1 is measured as follows.
A measuring movable mirror (measuring light reflecting mirror) 24 provided with a piezo element is arranged at the focal position of the wavelength λ1 of the lens 25 to be tested. The coherent light of wavelength λ1 emitted from the laser 1 is divided into reference light and measurement light by a beam splitter (light splitting and coupling element) 7, and the reference light has a thickness that is ¼ that of the beam splitter 7. Is transmitted through the λ1 transmission filter 10 having a refractive index of λ1, irradiated to and reflected by a reference movable mirror (reference light reflecting mirror) 13 having a piezo element, transmitted through the λ1 transmission filter 10 again, and returned to the beam splitter 7. The measurement light passes through the test lens 25, focuses on the measurement movable mirror 24, is reflected, passes through the test lens 25 again, and returns to the beam splitter 7.
In the beam splitter 7, the return light of the measurement light and the return light of the reference light are overlapped to form an interference fringe having the wavelength λ1. The interference fringe having the wavelength λ1 is sequentially transmitted through the beam splitter 8, the beam splitter 9, the wavelength selection filter 16, and the wavelength selection filter 17, and then formed on the pixel of the CCD camera (light detection means) 21 by the lens 18. The
Interference fringe image data photographed by the CCD camera 21 is taken into a personal computer and processed. When the Fourier transform method is used, the image data captured in the personal computer can be used for processing as it is, but when the number of stripes is insufficient, the reference movable mirror 13 can be tilted. In order to increase the number of fringes, the reference movable mirror 13 is tilted so that the angle formed when the measurement light and the reference light overlap is increased. Further, when it is desired to reduce the number of fringes, the reference movable mirror 13 is tilted so as to reduce the angle formed when the measurement light and the reference light overlap. When the angle formed when the measurement light and the reference light overlap is zero, the number of fringes is zero.

ここでは一般的に知られている４ステップ法を例に説明する。
位相ステップ法とは、基準可動ミラー１３で反射した参照光と、被検レンズ２５を透過した計測光とによって形成された干渉縞から位相情報を導く手段である。具体的には参照光路と計測光路の差を既知量だけ変化させて得られる複数の干渉縞画像から位相情報を導く手段である。４ステップ法の場合、計測光路と参照光路の差を４分の１波長ずつずらして得られる４つの干渉縞画像｜１、｜２、｜３、｜４の強度分布を用いる。｜１、｜２、｜３、｜４の干渉縞画像を形成する計測光路と参照光路の位相差はそれぞれ０、π／２、π、３π／２である。｜１、｜２、｜３、｜４の強度分布から位相情報φは式１でもとめることが可能である。
φ＝ｔａｎ-1[（｜２−｜１）／（｜１−｜３）]・・・式１
この方法に基づいて位相ステップをするには位相ステップ量単位をπ／２として０、（π／２）π、π、（３／２）πと変化させた４枚の画像が必要となる。これらの画像を撮影するには基準可動ミラー１３の移動量を０、（１／８）λ１、（１／４）λ１、（３／８）λ１と変化させて撮影し、パソコンにて式１に代入して計算すれば可能となる。 Here, a generally known four-step method will be described as an example.
The phase step method is means for deriving phase information from interference fringes formed by the reference light reflected by the reference movable mirror 13 and the measurement light transmitted through the lens 25 to be examined. Specifically, this is means for deriving phase information from a plurality of interference fringe images obtained by changing the difference between the reference optical path and the measurement optical path by a known amount. In the case of the 4-step method, intensity distributions of four interference fringe images | 1, | 2, | 3, and | 4 obtained by shifting the difference between the measurement optical path and the reference optical path by a quarter wavelength are used. The phase differences between the measurement optical path and the reference optical path that form the interference fringe images of | 1, | 2, | 3, and | 4 are 0, π / 2, π, and 3π / 2, respectively. From the intensity distribution of | 1, | 2, | 3, and | 4, the phase information φ can also be obtained from Equation 1.
φ = tan −1 [(| 2- | 1) / (| 1- | 3)]... Formula 1
In order to perform the phase step based on this method, four images are required in which the phase step amount unit is changed to 0, (π / 2) π, π, and (3/2) π with π / 2. In order to capture these images, the amount of movement of the reference movable mirror 13 is changed to 0, (1/8) λ1, (1/4) λ1, and (3/8) λ1. This can be done by substituting

次にλ２における測定について説明する。ピエゾ素子を備えた測定可動ミラー２４を被検レンズ２５の波長λ２の焦点位置に配置する。レーザ２から出た波長λ２の可干渉性光はビームスプリッタ８により参照光と計測光に分けられ、参照光はビームスプリッタ８と同じ厚さを持ち、同等の屈折率を持つλ２透過フィルタ１１を透過し、ピエゾ素子を備えた基準可動ミラー１４に照射されて反射し、再びλ２透過フィルタ１１を透過してビームスプリッタ８に戻る。計測光は被検レンズ２５を透過して測定可動ミラー２４上に焦点を結び、反射されて再び被検レンズ２５を透過し、ビームスプリッタ７を透過してビームスプリッタ８に戻る。ビームスプリッタ８で計測光と参照光が重ね合わされ、波長λ２の干渉縞が形成される。波長λ２の干渉縞は、ビームスプリッタ９、波長選択フィルタ１６を透過し、波長選択フィルタ１７で反射されレンズ１９によってＣＣＤカメラ２２の画素上に結像される。
ＣＣＤカメラ２２によって撮影した干渉縞画像はパソコンに取り込んで処理を行う。フーリエ変換法を用いる際には、パソコンに取り込んだ画像をそのまま処理に用いることができるが、縞の本数が足りない場合には基準可動ミラー１４を傾けることで可能となる。縞数を増やすには計測光と参照光が重なる時の成す角度が大きくなるように基準可動ミラー１４を傾ける。また、縞数を減らしたい時には計測光と参照光が重なる時の成す角度を小さくなるように基準可動ミラー１４を傾ける。計測光と参照光が重なる時の成す角度が0の時、縞数は0本となる。位相ステップ法を用いる際には、基準可動ミラー１４を等間隔で移動させることで可能となる。４ステップ法の場合、基準可動ミラー１４の移動量を０、（１／８）λ２、（１／４）λ２、（３／８）λ２と変化させて撮影し、パソコンにて式１に代入して計算すれば可能となる。 Next, the measurement at λ2 will be described. A measurement movable mirror 24 provided with a piezo element is arranged at the focal position of the wavelength λ2 of the lens 25 to be measured. The coherent light of wavelength λ2 emitted from the laser 2 is divided into reference light and measurement light by the beam splitter 8, and the reference light has the same thickness as the beam splitter 8 and the λ2 transmission filter 11 having the same refractive index. The light is transmitted, irradiated to and reflected by the reference movable mirror 14 having a piezoelectric element, passes through the λ2 transmission filter 11 again, and returns to the beam splitter 8. The measurement light passes through the test lens 25, focuses on the measurement movable mirror 24, is reflected, passes through the test lens 25 again, passes through the beam splitter 7, and returns to the beam splitter 8. The measurement light and the reference light are overlapped by the beam splitter 8 to form an interference fringe having a wavelength λ2. The interference fringes having the wavelength λ 2 are transmitted through the beam splitter 9 and the wavelength selection filter 16, reflected by the wavelength selection filter 17, and imaged on the pixel of the CCD camera 22 by the lens 19.
The interference fringe image photographed by the CCD camera 22 is taken into a personal computer and processed. When the Fourier transform method is used, an image taken in a personal computer can be used as it is for processing, but when the number of stripes is insufficient, the reference movable mirror 14 can be tilted. To increase the number of fringes, the reference movable mirror 14 is tilted so that the angle formed when the measurement light and the reference light overlap is increased. Further, when it is desired to reduce the number of fringes, the reference movable mirror 14 is tilted so as to reduce the angle formed when the measurement light and the reference light overlap. When the angle formed when the measurement light and the reference light overlap is zero, the number of fringes is zero. When using the phase step method, it is possible to move the reference movable mirror 14 at equal intervals. In the case of the 4-step method, the amount of movement of the reference movable mirror 14 is changed to 0, (1/8) λ2, (1/4) λ2, and (3/8) λ2, and the result is assigned to Equation 1 on a personal computer. It will be possible to calculate.

次にλ３における測定について説明する。ピエゾ素子を備えた測定可動ミラー２４を被検レンズ２５のλ３の焦点位置に配置する。レーザ３から出た波長λ３の可干渉性光はビームスプリッタ９により参照光と計測光に分けられ、参照光はビームスプリッタ７、ビームスプリッタ８と同じ厚さを持ち、同等の屈折率を持つλ３透過フィルタ１２を透過し、ピエゾ素子を備えた基準可動ミラー１５に照射されて反射し、再びλ３透過フィルタ１２を透過してビームスプリッタ９に戻る。計測光は被検レンズ２５を透過して測定可動ミラー２４上に焦点を結び反射されて再び被検レンズ２５を透過し、ビームスプリッタ７、ビームスプリッタ８を透過してビームスプリッタ９に戻る。ビームスプリッタ９で計測光と参照光が重ね合わされ、波長λ３の干渉縞が形成される。波長λ３の干渉縞は、波長選択フィルタ１６で反射されてレンズ２０によってＣＣＤカメラ２３の画素上に結像される。
ＣＣＤカメラ２３によって撮影した干渉縞画像はパソコンに取り込ンで処理を行う。フーリエ変換法を用いる際には、パソコンに取り込んだ画像をそのまま処理に用いることができるが、縞の本数が足りない場合には基準可動ミラー１５を傾けることで可能となる。縞数を増やすには計測光と参照光が重なる時の成す角度が大きくなるように基準可動ミラー１５を傾ける。また、縞数を減らしたい時には計測光と参照光が重なる時の成す角度を小さくなるように基準可動ミラー１５を傾ける。計測光と参照光が重なる時の成す角度が0の時、縞数は0本となる。位相ステップ法を用いる際には、基準可動ミラー１５を等間隔で移動させることで可能となる。４ステップ法の場合、基準可動ミラー１５の移動量を０、（１／８）λ３、（１／４）λ３、（３／８）λ３と変化させ撮影し、パソコンにて式１に代入して計算すれば可能となる。 Next, the measurement at λ3 will be described. A measurement movable mirror 24 provided with a piezo element is arranged at the focal position of λ3 of the lens 25 to be examined. The coherent light of wavelength λ3 emitted from the laser 3 is divided into reference light and measurement light by the beam splitter 9, and the reference light has the same thickness as the beam splitter 7 and the beam splitter 8 and has the same refractive index λ3. The light passes through the transmission filter 12, is irradiated and reflected on the reference movable mirror 15 having a piezo element, passes through the λ3 transmission filter 12 again, and returns to the beam splitter 9. The measurement light passes through the test lens 25, is focused on the measurement movable mirror 24, is reflected, passes through the test lens 25 again, passes through the beam splitter 7 and the beam splitter 8, and returns to the beam splitter 9. The beam splitter 9 superimposes the measurement light and the reference light to form an interference fringe having a wavelength λ3. The interference fringes having the wavelength λ3 are reflected by the wavelength selection filter 16 and imaged on the pixels of the CCD camera 23 by the lens 20.
The interference fringe image photographed by the CCD camera 23 is taken into a personal computer and processed. When the Fourier transform method is used, an image captured in a personal computer can be used for processing as it is, but when the number of stripes is insufficient, the reference movable mirror 15 can be tilted. In order to increase the number of fringes, the reference movable mirror 15 is tilted so that the angle formed when the measurement light and the reference light overlap is increased. Further, when it is desired to reduce the number of fringes, the reference movable mirror 15 is tilted so as to reduce the angle formed when the measurement light and the reference light overlap. When the angle formed when the measurement light and the reference light overlap is zero, the number of fringes is zero. When using the phase step method, it is possible to move the reference movable mirror 15 at equal intervals. In the case of the four-step method, the amount of movement of the reference movable mirror 15 is changed to 0, (1/8) λ3, (1/4) λ3, (3/8) λ3, and the result is assigned to Equation 1 on a personal computer. It becomes possible if it calculates.

λ１、λ２、λ３のそれぞれの測定において縞数を同一にしたい時には、測定可動ミラー２４とビームスプリッタ７の間のλ１における光学的距離と、ビームスプリッタ７と基準可動ミラー１３の間のλ１における光学的距離を等しくし、かつ測定可動ミラー２４とビームスプリッタ８の間のλ２における光学的距離と、ビームスプリッタ８と基準可動ミラー１４の間のλ２における光学的距離等しくし、かつ測定可動ミラー２４とビームスプリッタ９の間のλ３における光学的距離と、ビームスプリッタ９と基準可動ミラー１５の間のλ３における光学的距離等しく配置することで可能となる。
このように配置して測定可動ミラー２４を固定した時、ＣＣＤカメラ２１、ＣＣＤカメラ２２、ＣＣＤカメラ２３で撮影された干渉縞の画像から色収差を計算することが出来る。ＣＣＤカメラ上に結像されたスポットの干渉縞が出ている範囲が等しいならば色収差はないことがわかる。特定の波長だけスポットの干渉縞が出ている範囲が異なる場合、その波長だけ色収差により被検レンズの焦点位置からずれていることになる。そのずれ量は被検レンズ２５からＣＣＤカメラまでの距離とスポットの干渉縞が出ている範囲の大きさのずれから計算で求めることが出来る。
また、透過物体の厚みの計測をする際には、被検レンズ２５の位置に被検透過物体を配置して同様の手段にて、複数波長λ１、λ２、λ３より得られた干渉縞を記録し、それらの画像からフーリエ変換法または位相ステップ法にて位相情報を抽出する。しかし、位相情報は０〜２πｒａｄの範囲で断続的な情報であるので定量的にしか位相情報を得ることができない。そこで断続的な情報を繋ぎあわすことで連続した位相情報が得られる。得られた位相情報、測定波長、測定波長に対する透過物体の屈折率から透過物体の厚みを得ることができる。しかし、ここで得られた厚みの情報は光が透過物体を２回透過した時のものであるために、実際の厚みの２倍となっているので、１／２倍することで実際の厚みを得ることができる。
本装置では複数波長それぞれから厚みの情報を得られるので、厚みの平均をとることでより高精度な測定が可能となる。さらにそれぞれの波長から得られた厚みの情報の差から透過物体の光の透過特性、特に各波長に対する屈折率分布特性を知ることができる。 When it is desired to make the number of fringes the same in each measurement of λ1, λ2, and λ3, the optical distance at λ1 between the measurement movable mirror 24 and the beam splitter 7 and the optical distance at λ1 between the beam splitter 7 and the reference movable mirror 13 are used. The optical distance at λ 2 between the measurement movable mirror 24 and the beam splitter 8, and the optical distance at λ 2 between the beam splitter 8 and the reference movable mirror 14, and the measurement movable mirror 24. This is possible by arranging the optical distance at λ3 between the beam splitters 9 and the optical distance at λ3 between the beam splitter 9 and the reference movable mirror 15 to be equal.
When the measurement movable mirror 24 is fixed in such a manner, the chromatic aberration can be calculated from the interference fringe images photographed by the CCD camera 21, the CCD camera 22, and the CCD camera 23. It can be seen that there is no chromatic aberration if the interference fringes of spots imaged on the CCD camera are equal. When the range in which the spot interference fringes are different by a specific wavelength is different, it is shifted from the focal position of the test lens by the chromatic aberration by that wavelength. The amount of deviation can be obtained by calculation from the deviation between the distance from the lens to be examined 25 to the CCD camera and the size of the area where the spot interference fringes appear.
Further, when measuring the thickness of the transmission object, the test transmission object is placed at the position of the test lens 25 and the interference fringes obtained from the plurality of wavelengths λ1, λ2, and λ3 are recorded by the same means. Then, phase information is extracted from those images by the Fourier transform method or the phase step method. However, since the phase information is intermittent information in the range of 0 to 2π rad, the phase information can be obtained only quantitatively. Therefore, continuous phase information can be obtained by connecting intermittent information. From the obtained phase information, measurement wavelength, and refractive index of the transmission object with respect to the measurement wavelength, the thickness of the transmission object can be obtained. However, since the thickness information obtained here is information obtained when light passes through the transmission object twice, the thickness information is twice the actual thickness. Can be obtained.
In this apparatus, thickness information can be obtained from each of a plurality of wavelengths, so that more accurate measurement can be performed by averaging the thicknesses. Furthermore, the light transmission characteristics of the transmissive object, particularly the refractive index distribution characteristics for each wavelength, can be known from the difference in thickness information obtained from each wavelength.

次に光路について説明する。
レーザ１、レーザ２、レーザ３から射出される可干渉性光は、ビームエキスパンダ４、ビームエキスパンダ５、及びビームエキスパンダ６により、それぞれ平行光にされ、ビームスプリッタ７、ビームスプリッタ８、及びビームスプリッタ９により、それぞれ計測光と参照光に分けられる。それぞれの参照光は、λ１透過フィルタ１０、λ２透過フィルタ１１、及びλ３透過フィルタ１２により、レーザ１、レーザ２、及びレーザ３から射出された光の波長毎に選択される。選択されたそれぞれの波長の光は、基準可動ミラー１３、基準可動ミラー１４、及び基準可動ミラー１５により、ビームスプリッタ７、ビームスプリッタ８、及びビームスプリッタ９までそれぞれ戻される。
一方、ビームスプリッタ７、ビームスプリッタ８、及びビームスプリッタ９により分けられた計測光は、すべて被検レンズ２５に照射され、被検レンズ２５を透過する。被検レンズ２５を透過した計測光は、測定稼動ミラー２４に照射されて反射し、ビームスプリッタ７、ビームスプリッタ８、ビームスプリッタ９まで戻される。ビームスプリッタ７、ビームスプリッタ８、ビームスプリッタ９まで戻されたそれぞれの波長の参照光と計測光は、重ね合わされることで、レーザ１、レーザ２、レーザ３から射出された光の波長の干渉縞を形成する。形成された干渉縞は、波長選択フィルタ１６と波長選択フィルタ１７により、レーザ１、レーザ２、レーザ３から射出された光の波長毎に分割し、それぞれの波長毎の干渉縞を得ることができ、この波長毎に分割された干渉縞をＣＣＤカメラ２１、ＣＣＤカメラ２２、ＣＣＤカメラ２３にて検出する。 Next, the optical path will be described.
The coherent light emitted from the laser 1, the laser 2, and the laser 3 is converted into parallel light by the beam expander 4, the beam expander 5, and the beam expander 6, respectively. The beam splitter 7, the beam splitter 8, and The beam splitter 9 separates the measurement light and the reference light. The respective reference lights are selected for each wavelength of the light emitted from the laser 1, the laser 2, and the laser 3 by the λ 1 transmission filter 10, the λ 2 transmission filter 11, and the λ 3 transmission filter 12. The selected light of each wavelength is returned to the beam splitter 7, the beam splitter 8, and the beam splitter 9 by the reference movable mirror 13, the reference movable mirror 14, and the reference movable mirror 15, respectively.
On the other hand, all the measurement lights divided by the beam splitter 7, the beam splitter 8, and the beam splitter 9 are irradiated to the test lens 25 and pass through the test lens 25. The measurement light that has passed through the test lens 25 is irradiated and reflected on the measurement operation mirror 24 and returned to the beam splitter 7, the beam splitter 8, and the beam splitter 9. The reference light and the measurement light of the respective wavelengths returned to the beam splitter 7, the beam splitter 8, and the beam splitter 9 are overlapped, thereby interference fringes of the wavelengths of the light emitted from the laser 1, laser 2, and laser 3. Form. The formed interference fringes can be divided for each wavelength of the light emitted from the laser 1, the laser 2 and the laser 3 by the wavelength selection filter 16 and the wavelength selection filter 17, and an interference fringe for each wavelength can be obtained. The interference fringes divided for each wavelength are detected by the CCD camera 21, the CCD camera 22, and the CCD camera 23.

なお、本装置では、光分割結合素子としてビームスプリッタを用いた場合で説明したが、ハーフミラーを用いてもよい。また、本装置では位相ステップ法を用いる際に基準可動ミラーを移動させたがレーザの発振波長を電流または電圧で制御し微小に波長を変えて位相ステップを行ってもよい。
また、光源からの干渉性光をそれぞれ周期的に射出させるとともに、光源の点滅周期に同期して開閉するシャッターを設けることが好ましい。このシャッターとしては、液晶シャッターや電子シャッターを用いることができ、オプティカルチョッパーを用いてもよい。
また、本装置では干渉縞検出手段としてCCDカメラを用いた場合で説明したがCMOSカメラやフィルム記録カメラを用いても同様の効果が得られる。フィルム記録カメラで検出した場合はスキャナ等の装置を使用しパソコン等の電子計算機に取り込むことで可能となる。
また、本装置では被検レンズの測定を例に挙げたが屈折率を持つ被検物体と組み合わされた光学部品、例えばガラス板とレンズの場合であっても測定は可能である。 In this apparatus, the beam splitter is used as the light splitting and coupling element. However, a half mirror may be used. In this apparatus, the reference movable mirror is moved when the phase step method is used. However, the phase step may be performed by changing the wavelength minutely by controlling the oscillation wavelength of the laser with current or voltage.
In addition, it is preferable to provide a shutter that periodically emits coherent light from the light source and opens and closes in synchronization with the blinking cycle of the light source. As this shutter, a liquid crystal shutter or an electronic shutter can be used, and an optical chopper may be used.
Further, in this apparatus, the case where a CCD camera is used as the interference fringe detecting means has been described, but the same effect can be obtained even if a CMOS camera or a film recording camera is used. When it is detected by a film recording camera, it can be obtained by using an apparatus such as a scanner and loading it into an electronic computer such as a personal computer.
In this apparatus, the measurement of the test lens is given as an example, but the measurement is possible even in the case of an optical component combined with a test object having a refractive index, for example, a glass plate and a lens.

本発明は、カメラ、顕微鏡、メガネなどの光学機器やＣＤ、ＤＶＤ、ＢＤ、HDＤＶＤなどの光記録装置などに用いるレンズ等の光学部品の収差測定及び、光ファイバーや光導路等の屈折率分布測定や光透過物体及び反射物体の形状計測などの位相測定に利用することができる。   The present invention provides aberration measurement of optical components such as lenses used in optical equipment such as cameras, microscopes, and glasses, and optical recording devices such as CD, DVD, BD, and HDDVD, and refractive index distribution measurement of optical fibers and optical paths. It can be used for phase measurement such as measurement of the shape of a light transmitting object and a reflecting object.

本発明の最良の形態を示す光計測装置の概略構成図1 is a schematic configuration diagram of an optical measuring device showing the best mode of the present invention. 従来の光計測装置の１つの光源を用いた収差測定用撮影部の概略図Schematic diagram of an aberration measurement imaging unit using one light source of a conventional optical measurement device 従来の光計測装置の複数の光源を用いた色収差測定用撮影部の概略図Schematic diagram of a chromatic aberration measurement photographing unit using a plurality of light sources of a conventional optical measuring device 従来の光計測装置の複数の光源を用いた干渉計測用撮影部の概略図Schematic diagram of imaging unit for interference measurement using multiple light sources of a conventional optical measurement device

符号の説明Explanation of symbols

１、２、３ レーザ
４、５、６ ビームエキスパンダ
７、８、９ ビームスプリッタ
１０ λ１透過フィルタ
１１ λ２透過フィルタ
１２ λ３透過フィルタ
１３、１４、１５ 基準可動ミラー
１６、１７ 波長選択フィルタ
１８、１９、２０ レンズ
２１、２２、２３ ＣＣＤカメラ
２４ 測定稼動ミラー
２５ 被検レンズ
1, 2, 3 Laser 4, 5, 6 Beam expander 7, 8, 9 Beam splitter 10 λ1 transmission filter 11 λ2 transmission filter 12 λ3 transmission filter 13, 14, 15 Reference movable mirror 16, 17 Wavelength selection filter 18, 19 , 20 Lens 21, 22, 23 CCD camera 24 Measurement operation mirror 25 Test lens

Claims (11)

可干渉性光を射出する光源と、
前記可干渉性光を計測光と参照光に分けるとともに、前記計測光の戻り光と前記参照光の戻り光を重ね合わせて干渉光を形成する光分割結合素子と、
前記光分割結合素子により分けられた前記計測光を反射する計測光反射鏡と、
前記光分割結合素子により分けられた前記参照光を反射する参照光反射鏡とを備えた光計測装置であって、
前記光源として、第１の光源と、前記第１の光源と波長の異なる可干渉性光を射出する第２の光源を設け、
前記光分割結合素子として、前記第１の光源の前記可干渉性光を第１の計測光と第１の参照光に分けるとともに前記第１の計測光の戻り光と前記第１の参照光の戻り光を重ね合わせて第１の干渉光を形成する第１の光分割結合素子と、前記第２の光源の前記可干渉性光を第２の計測光と第２の参照光に分けるとともに前記第２の計測光の戻り光と前記第２の参照光の戻り光を重ね合わせて第２の干渉光を形成する第２の光分割結合素子を設け、
前記参照光反射鏡として、前記第１の参照光を反射する第１の参照光反射鏡と、前記第２の参照光を反射する第２の参照光反射鏡を設け、
前記計測光反射鏡では、前記第１の計測光と前記第２の計測光とを反射させ、
前記第１の干渉光は、前記第２の光分割結合素子を透過し、
前記第２の光分割結合素子を透過する前記第１の干渉光と、前記第２の光分割結合素子で形成される前記第２の干渉光とを分割する波長選択フィルタを設け、
前記波長選択フィルタで分割された前記第１の干渉光と前記第２の干渉光とを個々に検出する光検出手段を設け、
前記計測光反射鏡と前記第１の光分割結合素子との間に被検レンズまたは屈折率をもつ被検物体を配置して前記被検レンズまたは前記被検物体の収差を計測することを特徴とする光計測装置。 A light source that emits coherent light;
Splitting the coherent light into measurement light and reference light, and a light splitting and coupling element that forms interference light by superimposing the return light of the measurement light and the return light of the reference light;
A measurement light reflecting mirror that reflects the measurement light divided by the light splitting and coupling element;
An optical measurement device comprising a reference light reflecting mirror that reflects the reference light divided by the light splitting and coupling element,
As the light source, a first light source and a second light source that emits coherent light having a wavelength different from that of the first light source are provided.
As the light splitting and coupling element, the coherent light of the first light source is divided into first measurement light and first reference light, and return light of the first measurement light and first reference light. A first light splitting and coupling element that superimposes return light to form first interference light, and the coherent light of the second light source is divided into second measurement light and second reference light, and Providing a second light splitting and coupling element that overlaps the return light of the second measurement light and the return light of the second reference light to form a second interference light;
As the reference light reflecting mirror, a first reference light reflecting mirror that reflects the first reference light and a second reference light reflecting mirror that reflects the second reference light are provided,
The measurement light reflecting mirror reflects the first measurement light and the second measurement light,
The first interference light passes through the second light splitting and coupling element,
Providing a wavelength selection filter that splits the first interference light transmitted through the second light splitting and coupling element and the second interference light formed by the second light splitting and coupling element;
Provided is a light detection means for individually detecting the first interference light and the second interference light divided by the wavelength selection filter,
A test lens or a test object having a refractive index is arranged between the measurement light reflecting mirror and the first light splitting and coupling element, and the aberration of the test lens or the test object is measured. An optical measuring device. 前記計測光反射鏡を可動式とし、前記計測光反射鏡と前記第１の光分割結合素子との光学的距離または角度を変更可能な構成としたことを特徴とする請求項１に記載の光計測装置。   2. The light according to claim 1, wherein the measurement light reflection mirror is movable, and an optical distance or angle between the measurement light reflection mirror and the first light splitting and coupling element can be changed. Measuring device. 前記参照光反射鏡を可動式とし、前記参照光反射鏡と前記光分割結合素子との光学的距離または角度を変更可能な構成としたことを特徴とする請求項１に記載の光計測装置。   The optical measurement apparatus according to claim 1, wherein the reference light reflecting mirror is movable, and an optical distance or angle between the reference light reflecting mirror and the light splitting and coupling element can be changed. 前記第１の光分割結合素子から前記計測光反射鏡までの距離と、前記第１の光分割結合素子から前記第１の参照光反射鏡までの光学的距離を等しくし、前記第２の光分割結合素子から前記計測光反射鏡までの光学的距離と、前記第２の光分割結合素子から前記第２の参照光反射鏡までの光学的距離を等しくしたことを特徴とする請求項１に記載の光計測装置。   The distance from the first light splitting and coupling element to the measurement light reflecting mirror is made equal to the optical distance from the first light splitting and coupling element to the first reference light reflecting mirror, and the second light The optical distance from the split coupling element to the measurement light reflecting mirror and the optical distance from the second optical split coupling element to the second reference light reflecting mirror are equal to each other. The optical measuring device described. 前記参照光反射鏡と前記光分割結合素子との間に透過フィルタを設けたことを特徴とする請求項１に記載の光計測装置。   The optical measurement apparatus according to claim 1, wherein a transmission filter is provided between the reference light reflecting mirror and the light division coupling element. 前記光源としてレーザ光源を用いたことを特徴とする請求項１に記載の光計測装置。   The optical measurement apparatus according to claim 1, wherein a laser light source is used as the light source. 前記光分割結合素子としてビームスプリッタを用いたことを特徴とする請求項１に記載の光計測装置。   The optical measuring device according to claim 1, wherein a beam splitter is used as the light splitting and coupling element. 前記光分割結合素子としてハーフミラーを用いたことを特徴とする請求項１に記載の光計測装置。   The optical measurement apparatus according to claim 1, wherein a half mirror is used as the light splitting and coupling element. 前記光検出手段としてＣＣＤカメラまたはCMOSカメラを用いたことを特徴とする請求項１に記載の光計測装置。   The optical measurement device according to claim 1, wherein a CCD camera or a CMOS camera is used as the light detection means. 前記光源として、第１の光源及び前記第２の光源と波長の異なる可干渉性光を射出する第３の光源を設け、
前記光分割結合素子として、前記第３の光源の前記可干渉性光を第３の計測光と第３の参照光に分けるとともに前記第３の計測光の戻り光と前記第３の参照光の戻り光を重ね合わせて第３の干渉光を形成する第３の光分割結合素子を設け、
前記参照光反射鏡として、前記第３の参照光を反射する第３の参照光反射鏡を設け、
前記計測光反射鏡では、前記第１の計測光、前記第２の計測光、及び前記第３の計測光を反射させ、
前記第１の干渉光は、前記第２の光分割結合素子及び前記第３の光分割結合素子を透過し、
前記第２の干渉光は、前記第３の光分割結合素子を透過し、
前記第３の光分割結合素子で形成される前記第３の干渉光を、前記第３の光分割結合素子を透過する前記第１の干渉光及び前記第２の干渉光から分割する波長選択フィルタを設けたことを特徴とする請求項１に記載の光計測装置。 As the light source, a third light source that emits coherent light having a wavelength different from that of the first light source and the second light source is provided.
As the light splitting and coupling element, the coherent light of the third light source is divided into third measurement light and third reference light, and the return light of the third measurement light and the third reference light Providing a third light splitting and coupling element that superimposes the return light to form third interference light;
As the reference light reflecting mirror, a third reference light reflecting mirror that reflects the third reference light is provided,
The measurement light reflecting mirror reflects the first measurement light, the second measurement light, and the third measurement light,
The first interference light passes through the second light splitting and coupling device and the third light splitting and coupling device,
The second interference light passes through the third light splitting and coupling element,
A wavelength selective filter that divides the third interference light formed by the third light splitting and coupling element from the first interference light and the second interference light transmitted through the third light splitting and coupling element. The optical measuring device according to claim 1, wherein: 請求項１から１０のいずれかに記載の光計測装置を用いた光計測方法であって、前記参照光反射鏡を所定量だけ移動させることで、前記参照光反射鏡と前記光分割結合素子との距離または角度を変化させ、変化させたそれぞれの前記光学的距離における前記干渉光を前記光検出手段によって検出することを特徴とする光計測方法。
The optical measurement method using the optical measurement device according to claim 1, wherein the reference light reflecting mirror, the light division coupling element, and the reference light reflecting mirror are moved by moving the reference light reflecting mirror by a predetermined amount. And measuring the interference light at each of the changed optical distances by the light detection means.
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