【発明の詳細な説明】「産業上の利用分野」この発明は光の干渉作用によって、粗な表面を持つ金属
加工表面の凹凸を非接触にて検査する装置に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an apparatus for non-contactly inspecting the irregularities of a metal processing surface having a rough surface by the interference effect of light.
「従来技術」光の干渉計であるフィゾー型干渉計では、単位縞当たり
の間隔距離が約０．３μｍであるため、被検体の凹凸差
が大きすぎると測定できなくなる。"Prior Art" In the Fizeau type interferometer, which is an optical interferometer, the interval distance per unit fringe is about 0.3 μm, so if the difference in unevenness of the object is too large, measurement cannot be performed.
そこで、それよりも凹凸差の大きなものを測定できる斜
入射干渉装置が開発されている。それは、第５図に示す
ようなレーザ発振器ａがら出射する可干渉性のレーザ光
をレンズにで平行光束になし、この光束を第１回折格子
すによって回折する。その回折された回折光のうち、＋
１次光を被検体Ｃの面上にて反射させる。そして、同時
にその反射された＋１次光と先の第１回折格子すを透過
した０次光とを第２回折格格子によって重ね合わせて干
渉させる。このように干渉縞を形成し、その干渉縞によ
って被検体Ｃの被検面の形状を測定する。Therefore, an oblique incidence interferometry device that can measure objects with a larger unevenness difference than that has been developed. In this method, a coherent laser beam emitted from a laser oscillator a as shown in FIG. 5 is converted into a parallel beam by a lens, and this beam is diffracted by a first diffraction grating. Of the diffracted light, +
The primary light is reflected on the surface of the subject C. At the same time, the reflected +1st-order light and the 0th-order light that has passed through the first diffraction grating are superimposed by the second diffraction grating to cause interference. Interference fringes are formed in this way, and the shape of the surface to be examined of the object C is measured using the interference fringes.
この斜入射干渉計は、第６図に示すように、第１回折格
子すのピッチをｄ３回折角度をθ、使用するレーザ光の
波長をλとすると、一般に、（ｓｉｎ θ）／λ＝１／
ｄが成立する。一方被検体Ｃの凹凸差がｈであるとその凹
凸差りによって発生する＋１次光の光路差Δ１は、Δ１ ＝ ２ ｈｓｉｎ θと表される。As shown in FIG. 6, in this grazing incidence interferometer, if the pitch of the first diffraction grating is d3, the diffraction angle is θ, and the wavelength of the laser beam used is λ, then (sin θ)/λ=1. /
d holds true. On the other hand, when the unevenness difference of the object C is h, the optical path difference Δ1 of the +1st-order light generated by the unevenness difference is expressed as Δ1 = 2 hsin θ.
ところで、この光路差Δ１によって１本の干渉縞が発生
する場合には、Δ１−２ ｈｓｉｎ θ＝λが、成立するので、この時の凹凸差りは感度を表すこと
になり、ｈ＝λ／（２ｓｉｎ θ） ＝ｄ／２と表すことができる。従って、Ｈｅ−Ｎｅガスを用いた
レーザ光の波長λが、６３２．８ｒ＋ｍ、 ＋ １次光
の回折角度θが、９．１度となる場合、（この時、第１
回折格子のピッチｄは４μｍの場合）には、感度が２μ
ｍとなり、フィゾー型干渉計で測定できながった大きな
凹凸差でも計測できるのである。By the way, when one interference fringe is generated due to this optical path difference Δ1, Δ1-2 hsin θ=λ holds true, so the difference in unevenness at this time represents the sensitivity, and h=λ/ It can be expressed as (2sin θ) = d/2. Therefore, when the wavelength λ of the laser beam using He-Ne gas is 632.8r+m, + the diffraction angle θ of the first-order light is 9.1 degrees, (at this time, the first-order
When the pitch d of the diffraction grating is 4 μm), the sensitivity is 2 μm.
m, making it possible to measure even large unevenness differences that cannot be measured with a Fizeau interferometer.
近年、波面測定の自動化をするためには、位相干渉測定
法が用いられていて、干渉計の２つの波面間の光路差は
、干渉模様の位相調整中に検出器の各分析部で測定され
る。例えば、Ｊ、Ｈ，Ｂｒｕｎｉｎｇ他著ｒＤｉｇｉｔ
ａｌ Ｗａｖｅｆｒｏｎｔ Ｍｅａｓｕｒｉｎｇ Ｉｎ
ｔｅｒｆｅｒｏｍｅｔｅｒ ｆｏｒ Ｔｅｓｔｉｎｇ
０ｐｔｉｃａｌ ５ｕｆａｃｅｓ ａｎｄ Ｌｅｎ
ｓｅｓ Ｊ［Ａｐｐｌｉｅｄ ０ｐｔｉｃｓ、第１８
巻、 ２６９Ｂ−２７０３頁（１９７４年）］やＧａ１
１ａｇｈｅｒ他の米国特許第８．６９４．０８８号（１
９７２年９月２６日発行） 、Ｎ、Ｂａ１ａｓｕｂｒａ
＊ａｎｉａｎの米国特許第４．２２５．２４０号（１９
８０年９月３０日発行）、Ｍ、５ｃｈａｈａ−著ｒＰｒ
ｏｃｅｅｄｉｎｇｓ ５ＰＩＥＪ ［８０６巻： １
８８−１９１頁（１９８１年） ］ 、Ｈ，Ｚ、Ｈｕ著
ｒＰｏｌａｒｉｚａｔｉｏｎ ｈｅｔ−ｅｒｏｄｙｎｅ
ｉｎｔｅｒｆｅｒｏｍｅｔｒｙ ｕｓｉｎｇ ａ
ｓｉｍｐｌｅ ｒｏｔａｔｉｎ−ｇ ａｎａｌｙｚｅｒ
Ｊ 、及び特開昭６２−１７７４２１などに開示がある
。In recent years, phase interferometry has been used to automate wavefront measurements, and the optical path difference between the two wavefronts of the interferometer is measured by each analysis section of the detector during phase adjustment of the interference pattern. Ru. For example, rDigit by J. H. Bruning et al.
al Wavefront Measuring In
Terferometer for Testing
0ptical 5ufaces and Len
ses J [Applied Optics, No. 18
Vol., pp. 269B-2703 (1974)] and Ga1
U.S. Pat. No. 8.694.088 to 1agher et al.
Published September 26, 1972), N, Ba1asubra
*anian U.S. Patent No. 4.225.240 (19
Published September 30, 1980), M, 5chaha-author rPr
oceedings 5PIEJ [Volume 806: 1
pp. 88-191 (1981) ], H, Z. Hu, Polarization het-erodyne
interferometry using a
simple rotatin-g analyzer
J, and Japanese Unexamined Patent Publication No. 62-177421.
位相測定干渉法は、高いデータ濃度を提供でき、ビーム
の強度分布に対してのみならず、光学素子や検出器の当
初の配置に関する幾何学的な歪みに対しても、影響を受
けにくい。ところが、この手法を用いての斜入射干渉計
による自動測定については開示されてない。そこで本出
願人は、この位相干渉測定法と斜入射干渉計を結び付け
るために、二つの異なる方法を試みた。しかしながら、
次の理由により困難が生じていた。その第１の方法は、
第７図に示すように、被検体Ｍを載置台５上で、重力加
速度の作用するＺ、方向に対して移動させ、光路差に変
化を与えることにより、干渉縞が位相変調するようにし
たのである。しかしながら、斜めより観察する被検体Ｍ
は、回折格子４より斜めより入射光を照射され、反射し
たレーザ光の進行方向ｄ、力方向対して直交する方向Ｘ
方向・Ｙ１方向に対して、被検体Ｍの像を結像面７に於
てｙ１方同に移動させる。すなわち、干渉縞に位相変調
が与えられると同時に、干渉縞が生じている被検体像が
移動してしまう。得られた画像の同一地点の異なる位相
情報を得るには、得られた画像のｘ１ｙ１方向の再移動
処理を行う必要がある。また、この画像を正確に移動さ
せるにはシステムを複雑にするか、ソフトウェアを追加
しなければならない。Phase-measuring interferometry can provide high data density and is insensitive not only to the intensity distribution of the beam but also to geometric distortions with respect to the original placement of optical elements and detectors. However, automatic measurement using a grazing incidence interferometer using this technique is not disclosed. Therefore, the present applicant tried two different methods to combine this phase interferometry method with a grazing incidence interferometer. however,
Difficulties arose due to the following reasons. The first method is
As shown in FIG. 7, the subject M was moved on the mounting table 5 in the Z direction where gravitational acceleration acts, and the optical path difference was changed so that the interference fringes were phase-modulated. It is. However, the subject M observed obliquely
is incident light obliquely irradiated from the diffraction grating 4, the traveling direction d of the reflected laser light, and the direction X perpendicular to the force direction.
The image of the subject M is moved in the y1 direction on the imaging plane 7 with respect to the Y1 direction. That is, at the same time that phase modulation is applied to the interference fringes, the object image in which the interference fringes are occurring moves. In order to obtain different phase information at the same point in the obtained image, it is necessary to re-move the obtained image in the x1y1 direction. Additionally, moving this image accurately requires a complicated system or additional software.
本出願人が試みた第２の方法は、第８図に示すように、
回折格子６の後に、ｄ２方向に対して直交方向に回折格
子１９を配置し、ｙ２方向に移動できる駆動装置１６、
例えば、圧電素子とこれを駆動する電圧制御装置等を設
けた。回折格子６により生じた干渉縞は、この回折格子
１９の格子信号に重畳され、新しい干渉縞が結像面７に
できる。The second method attempted by the applicant is as shown in Figure 8.
A driving device 16 that arranges a diffraction grating 19 in a direction perpendicular to the d2 direction after the diffraction grating 6 and can move it in the y2 direction;
For example, a piezoelectric element and a voltage control device for driving the piezoelectric element were provided. The interference fringes generated by the diffraction grating 6 are superimposed on the grating signal of the diffraction grating 19, and new interference fringes are created on the imaging plane 7.
しかしながら、斜めより観察する被検体Ｍの像は、Ｘｚ
Ｖｚ平面上にｙ２方向に縮小された像になる。発生する
干渉縞の間隔を一定に保つためには、回折格子４及び６
とは異なる特殊な格子を制作する必要性があった。また
、縮小された像を光学系８で、修正したのち、この後ろ
に格子を配置して、位相変調を加える場合でも、この格
子の後ろに受光素子用の像倍率調整用光学系を配置しな
ければならない。However, the image of the subject M observed obliquely is
The image is reduced in the y2 direction on the Vz plane. In order to keep the interval between the generated interference fringes constant, the diffraction gratings 4 and 6 are
There was a need to create a special grid that was different from the previous one. Furthermore, even if a grating is placed behind the reduced image after it is corrected by the optical system 8 and phase modulation is applied, the optical system for adjusting the image magnification for the light receiving element is placed behind the grating. There must be.
「発明が、解決しようとする問題点」ところで、このような斜入射干渉計にあっては、フィゾ
ー型干渉計での干渉縞の間隔０．３μｍに比べると、干
渉縞の間隔が２４０μｍというように計測感度が低い。"Problems to be Solved by the Invention" By the way, in such a grazing incidence interferometer, the spacing between interference fringes is 240 μm, compared to 0.3 μm in a Fizeau type interferometer. The measurement sensitivity is low.
それで被検面の高低差が大きくても測定できる。しかし
、従来の斜入射干渉計そのものは縞模様の解析を目視で
するためのものであり、干渉計の微調整は測定者が行な
っていた。その微調整の方法は被検体Ｍが斜入射干渉計
の測定領域にはいるように、載置台５上で被検体Ｍ ＠
ｚ 。Therefore, measurements can be made even if the surface to be tested has a large difference in height. However, conventional grazing-incidence interferometers are used to visually analyze fringe patterns, and fine adjustments to the interferometer are performed by the measurer. The method of fine adjustment is to place the object M on the mounting table 5 so that it enters the measurement area of the oblique incidence interferometer.
z.
方向に対して移動させると共に、ｘｙ方向でなす平面で
の回転、並びにＸ＋ｙｔ方向に移動させる。即ち、３次
元的に移動させて調整をしていた。このため、従来開示
された斜入射干渉計は、縞模様が単純でかつ、データの
濃度（コントラスト）が充分である被検体Ｍにしか適用
されず形状の計測はできなかったのである。In addition to moving in the direction, rotation on a plane made in the xy direction, and moving in the X+yt direction. That is, adjustments were made by moving three-dimensionally. For this reason, the conventionally disclosed grazing incidence interferometers were applicable only to objects M with simple striped patterns and sufficient data density (contrast), and could not measure the shape.
この発明は、以上に述べたような従来の欠点を補うため
に、前記干渉計に位相測定法を組み合わせることによっ
て、面性状が荒い被検体を自動測定できる斜入射干渉自
動測定装置を提供することを目的とする。In order to compensate for the conventional drawbacks as described above, the present invention provides an automatic oblique incidence interference measuring device that can automatically measure a specimen with a rough surface texture by combining the interferometer with a phase measurement method. With the goal.
「問題点を解決するための手段」本発明の装置は、可干渉性の光を出射する出射手段、こ
の出射手段から出射された光線を発散させる光学手段、
この光学手段透過後の光線を平行光線束に形成する平行
光束形成手段、この平行光線形成手段透過後の光を、特
定方向に回折される回折光線と直進透過する透過光線と
二分割する第１回折格子と、被検面検査用の被検体の載
置台と、第１回折格子と同一の第２回折格子とにより、
この第２回折格子によって回折された回折光線と、第１
回折格子により回折された後、被検面で反射され第２回
折格子を透過した光線との干渉作用により形成された干
渉縞をつくる手段。"Means for Solving the Problems" The device of the present invention includes an output means for outputting coherent light, an optical means for diverging the light beam emitted from the output means,
A parallel light beam forming means for forming the light beam after passing through the optical means into a parallel light beam; a first means for dividing the light after passing through the parallel light beam forming means into a diffracted light beam that is diffracted in a specific direction and a transmitted light beam that is transmitted in a straight line; With the diffraction grating, the specimen mounting table for inspecting the surface to be inspected, and the second diffraction grating that is the same as the first diffraction grating,
The diffracted light beam diffracted by this second diffraction grating and the first
Means for creating interference fringes formed by interference with a light beam that has been diffracted by a diffraction grating, reflected by a surface to be measured, and transmitted through a second diffraction grating.
前記構成に、第１、第２回折格子のいずれか一方を２方
向に動かせる機械機構手段、全ての配列点にわたって、
前記位相変調の少なくとも１周期の全期間中、前記干渉
縞の輻射エネルギーを感光検知する手段、例えば、２次
元の半導体アレーを備えたカメラ、前記干渉縞に於て感
光検出された輻射エネルギーを、被検体からの波面表示
する位相地図或は位相画像に変換する構成装置を付加す
ることによる手段を構じた。The configuration includes a mechanical mechanism that can move either the first or second diffraction grating in two directions, over all the array points,
During the entire period of at least one period of the phase modulation, a means for photosensitively detecting the radiant energy of the interference fringes, for example, a camera equipped with a two-dimensional semiconductor array, the radiant energy photosensitively detected in the interference fringes, A means for converting the wavefront from the object into a phase map or a phase image was added.
「実施例」本発明は、斜入射干渉計によって形成される干渉縞の位
相を測定するものである。位相を変調する手段によって
、得られた干渉縞は、画像手段によって感光検知され、
その信号はコンピュータ処理によって位相の計算をし、
被検体の表面の凹凸を示す地図或は、画像を作成する。"Example" The present invention measures the phase of interference fringes formed by a grazing incidence interferometer. The interference fringes obtained by the means for modulating the phase are photosensitively detected by the imaging means,
The phase of the signal is calculated by computer processing,
A map or image showing the unevenness of the surface of the subject is created.
これらのデータを基にして、予め決めた、欠陥判定値と
比較して、被検体が欠陥であるかどうかを判断する。Based on these data, it is compared with a predetermined defect determination value to determine whether or not the object is defective.
以下、この発明の実施例について添付図を参照しながら
説明する。第１図（ａ）及び（ｂｌは、この発明に係わ
る干渉計Ａ部分と処理部Ｃからなる装置を示す。干渉計
Ａはレーザ発振器１と、発散レンズ２と、コリメーター
レンズ３と、第１回折格子４と、載置台５と、第２回折
格子６と、像面７に干渉縞Ｂを結像させる光学素子ユニ
ット８を持ち、像面７に干渉縞Ｂを形成する。Embodiments of the present invention will be described below with reference to the accompanying drawings. 1(a) and (bl) show an apparatus consisting of an interferometer part A and a processing part C according to the present invention.The interferometer A includes a laser oscillator 1, a diverging lens 2, a collimator lens 3, It has a first diffraction grating 4 , a mounting table 5 , a second diffraction grating 6 , and an optical element unit 8 for forming an image of interference fringes B on an image plane 7 .
像面７には、干渉縞Ｂを走査する光電変換部９を設ける
。処理部Ｃは光電変換部９で所定のデータを得て、測定
のために必要な処理を行う。データ収集とか処理部Ｃの
構成は後述の機能を有する構成であれば適宜である。A photoelectric conversion unit 9 for scanning the interference fringes B is provided on the image plane 7 . The processing section C obtains predetermined data from the photoelectric conversion section 9 and performs necessary processing for measurement. The data collection and processing section C may have any suitable configuration as long as it has the functions described below.
なお、第１図（ａ）の記号１０は反射プリズムで光路を
９０度折曲する。１１はピンホールであり、発散レンズ
２に付着した塵により発生する有害な散乱光を除去する
。１２は反射ミラーで光路を９０折曲曲する。これらの
装置全体は図示以外の防振装置上に載置する。Note that symbol 10 in FIG. 1(a) is a reflecting prism that bends the optical path by 90 degrees. A pinhole 11 removes harmful scattered light generated by dust attached to the diverging lens 2. 12 is a reflecting mirror that bends the optical path by 90 degrees. These entire devices are placed on a vibration isolator other than what is shown.
レーザ発振器１は、可干渉光を出射するものであり、本
発明の実施例にあっては出力ＩＷのアルゴン（Ａｒ）レ
ーザを用いた。このアルゴンレーザから出射される５１
１．４ｎｍの緑色光線は、被検体測定用の光線とする。The laser oscillator 1 emits coherent light, and in the embodiment of the present invention, an argon (Ar) laser with an output of IW is used. 51 emitted from this argon laser
The 1.4 nm green light beam is used for measuring the object.
発散レンズ２は、レーザ発振器１から出射されたレーザ
光を発散させる。The diverging lens 2 diverges the laser light emitted from the laser oscillator 1.
コリメーターレンズ３は、ピンホール１１を通過し反射
ミラー１２で反射してきたレーザ光を平行な光束に形成
する。The collimator lens 3 forms the laser beam that has passed through the pinhole 11 and been reflected by the reflection mirror 12 into a parallel beam of light.
第１回折格子４は、コリメーターレンズ３により平行光
束となったレーザ光を回折させるためのものであり、こ
の実施例にあっては、平面を機械的に刻設して多数の溝
を形成したものから構成されているが、ホログラフィッ
ク格子を用いることも可能である。第１回折格子４によ
っって回折されたレーザのうち＋１次光αと、第１回折
格子４で回折されずに直進透過する０次光βを被検体Ｔ
測定用の光線とする。The first diffraction grating 4 is for diffracting the laser beam that has been made into a parallel beam by the collimator lens 3, and in this embodiment, a large number of grooves are formed by mechanically carving a flat surface. However, it is also possible to use a holographic grating. The +1st order light α of the laser diffracted by the first diffraction grating 4 and the 0th order light β which is transmitted straight without being diffracted by the first diffraction grating 4 are transferred to the subject T.
It is used as a light beam for measurement.
第２回折格子６は、回折格子４と同一のもので、第３図
に示すように、第１回折格子４によって回折されて被検
体Ｔの検査面で反射された＋１次光γと第１回折格子４
で回折されずにそのまま直進透過したＯ次光βとを重ね
干渉させるや像面７に干渉縞Ｂ１を結像させる光学素子
ユニット８は、光電変換部９の受光サイズにあった大き
さに干渉縞Ｂ１の大きさを換え、像面７に結像させると
共に回折格子６によって生じた不要な多次光や干渉縞を
除去する。The second diffraction grating 6 is the same as the diffraction grating 4, and as shown in FIG. Diffraction grating 4
The optical element unit 8 forms interference fringes B1 on the image plane 7 by superimposing and interfering with the O-order light β that has passed straight through without being diffracted by the optical element unit 8. The size of the fringe B1 is changed to form an image on the image plane 7, and unnecessary multi-order light and interference fringes generated by the diffraction grating 6 are removed.
光電変換部９は二次元の半導体カメラとする。The photoelectric conversion unit 9 is a two-dimensional semiconductor camera.
光電変換部９からは、光信号を出力し画像記憶手段をも
つユニット１４へ供給する。ユニット１４は、光電変換
部９からの光信号を時系列的に量子化を行い、量子化デ
ータを記録再生する。また、ユニット１４は、コンピュ
ータ１３のコマンドの形式で記録再生し、前記データを
コンピュータ１３が自由に読み書きする。The photoelectric conversion section 9 outputs an optical signal and supplies it to a unit 14 having image storage means. The unit 14 quantizes the optical signal from the photoelectric conversion section 9 in time series, and records and reproduces the quantized data. Further, the unit 14 records and reproduces data in the form of commands from the computer 13, and the computer 13 freely reads and writes the data.
コンピュータ１３からの電子出力１７は電圧制御器１５
に供給され、所定の時間的に変化する信号１８を圧電素
子１６に供給し、第２回折格子６を光軸（レーザ光の進
行方向）と前記回折格子の２方向に移動させる。圧電素
子１６は、干渉縞Ｂが一方向に走査するように、即ち位
相変調が行なえるように回折格子６を動かすのである。Electronic output 17 from computer 13 is connected to voltage controller 15
A predetermined time-varying signal 18 is supplied to the piezoelectric element 16, and the second diffraction grating 6 is moved in two directions: the optical axis (the traveling direction of the laser beam) and the diffraction grating. The piezoelectric element 16 moves the diffraction grating 6 so that the interference fringes B scan in one direction, that is, phase modulation can be performed.
干渉模様の位相地図或は位相画像は、以下の方法を用い
て作成する。第１図（ｂ）に示すように被検体Ｔを理想
の鏡面体にして載置台５におく。第２図に像面７の干渉
縞Ｂ、に対して、横断方向の光の強度分布を示す。干渉
縞Ｂ、の光の強度は横断方向に正弦波状に現われる。The phase map or phase image of the interference pattern is created using the following method. As shown in FIG. 1(b), the subject T is made into an ideal mirror body and placed on the mounting table 5. FIG. 2 shows the intensity distribution of light in the transverse direction with respect to the interference fringes B on the image plane 7. The light intensity of interference fringes B appears sinusoidally in the transverse direction.
第１図（ｂｌにおいて、第２回折格子６に設置した圧電
素子１６が第２回折格子６を２方向に移動すると、この
干渉縞Ｂ、はその振幅と周期を一定に保ちながら、第２
図中の右方または左方に移動する。即ち、位相が変化す
るのである。干渉縞の強度を式で表すと、１（Ｘ＋！／＋６） ＝Ｉｏ （１＋ｒ ｃｏｓ ［φ
（ｘ、ｙ）＋６］ ） （１）各信号の位相差φが、求
めるべき被検体Ｔの形状に相当する位相分布である。位
相分布φ（ｘ、ｙ）を計算するには、まず、第２回折格
子６の移動による位相δをＮ段階変化させるものとし、
それに対応する干渉縞強度分布■、・Ｉ（Ｘ＋Ｌδ、）
を式にすると、 １１！
＝Ｉｌｌ ［１＋γ（ｃｏｓφｃｏｓδｌ５ｉｎφｓ
ｉｎδ正］＝ａ、＋ａ、ｃｏｓ ６１＋ａ、ｓｉｎ
δＩ（２）ただし、ａｏ” Ｉｏ
（３）ａ、＝ １．γＣＯ３φ
（４）ａ２＝−１ｏｙｓｉｎφ
（５）■。：光強度分布のバイアス成分■。γ ：干渉縞の光強度振幅成分ｘ、ｙ ：Ｘ方向、ｙ方向は、記憶された干渉縞の一
方向でＸ方向とｙ方向は直交するもの゛とする。In FIG. 1 (bl), when the piezoelectric element 16 installed on the second diffraction grating 6 moves the second diffraction grating 6 in two directions, this interference pattern B, while keeping its amplitude and period constant,
Move to the right or left in the diagram. That is, the phase changes. Expressing the intensity of interference fringes using the formula, 1(X+!/+6) = Io (1+r cos [φ
(x,y)+6]) (1) The phase difference φ between each signal is a phase distribution corresponding to the shape of the subject T to be determined. To calculate the phase distribution φ(x, y), first, the phase δ due to the movement of the second diffraction grating 6 is changed by N steps,
Corresponding interference fringe intensity distribution■,・I(X+Lδ,)
If we convert it into a formula, we get 11!
=Ill [1+γ(cosφcosδl5inφs
inδ positive]=a, +a, cos 61+a, sin
δI (2) However, ao” Io
(3) a, = 1. γCO3φ
(4) a2=-1oysinφ
(5)■. : Bias component of light intensity distribution■. γ: Light intensity amplitude components of interference fringes x, y: The X and Y directions are one direction of the stored interference fringes, and the X and Y directions are orthogonal.
ここで、■１実測値をＩ！ Ｘ＋Ｌδ正とすると、位相
φを求める問題は、誤差を含んだ１．から最も確からし
いφを求める問題に帰着できる。このため、測定値１．
理論値■１差を最小にする−よう、ａｏ＋ａｌ＋ａ２を
決め、ａｌ＋ ａｘからφを計算するとすると、差の指
標Ｅはこの最小値を取るａｏ、 ”ｌ＋ ８２を決めると、位
相分布とコントラストは、φ（ｘ、ｙ）・−ｔａｎ−’ （ａｚ／ａｔ ）
（７）γ（χ、ｙ）・（ａｌ”＋ａｚ”）／ａ
ｏ （８）（７） （８）式で示される。Here, ■1 actual measurement value I! Assuming that X+Lδ is positive, the problem of finding the phase φ is 1. This can be reduced to the problem of finding the most probable φ. Therefore, the measured value 1.
Theoretical value ■1 If we decide ao + al + a2 and calculate φ from al + ax so as to minimize the difference, then the difference index E takes this minimum value ao, ``l + 82 is determined, and the phase distribution and contrast are as follows. φ(x, y)・-tan-' (az/at)
(7) γ(χ, y)・(al”+az”)/a
o (8) (7) It is shown by the formula (8).
実測された光の強度分布から所望の位相信号を、前記不
要信号を分解して求めることができる。なお、本実施例
では、回折格子６を、移動する機構として圧電素子及び
圧電素子制御用高電圧発生装置としたが、微少を高速で
移動可能な機構、例えば超磁歪材（ＲＦｅ２など：Ｒ５
希土類元素）及び磁場発生制御装置を組合せたものなど
も適用可能である。A desired phase signal can be obtained from the actually measured light intensity distribution by decomposing the unnecessary signal. In this embodiment, the diffraction grating 6 is made of a piezoelectric element and a high voltage generator for controlling the piezoelectric element as a moving mechanism, but a mechanism that can move minute particles at high speed, such as a giant magnetostrictive material (RFe2, etc.: R5
A combination of rare earth elements) and a magnetic field generation control device is also applicable.
「効 果」この発明に係わる光学的形状測定装置により求めた被検
体の計測結果を、３次元立体表示したものを第４図に示
す。等間隔のラインは被検体が平らな面であることを示
し、ラインの間隔はおおよそ１００μｍである。被検体
７表面の中央部のラインの乱れは、被検体Ｔの中央部が
内部に向かってくぼんでいることを示している。この第
４図の場合約１０μｍのくぼみが読み取れた。本実施例
では、第２回折格子６を移動させることにより、被検体
Ｔを移動させることなく、被検体７面からできる干渉縞
Ｂ１に位相変調を容易に与えることができる。光電変換
部９によって所定時間毎に干渉縞Ｂ、を操作して、不要
信号を含む光の強度信号の分布を測定する。その後に実
施例で説明した計算式を用い、この光の強度信号の分布
を表す関数に対してフーリエ級数展開を施す。そして、
正弦項ならびに余弦項を演算する共にこれらの比を演算
し、干渉縞Ｂ＋の位相信号を分離する。この位相信号か
ら前記被検体Ｔの凹凸状態を求め、形状測定を行うので
ある。本発明によって、被検体の面性状が荒くても測定
できるし、また自動測定ができるようになったので、多
数の被検体を短時間の内に精度よく測定することができ
るのである。"Effects" FIG. 4 shows a three-dimensional display of the measurement results of the object determined by the optical shape measuring device according to the present invention. Equally spaced lines indicate that the object is a flat surface, and the line spacing is approximately 100 μm. The disturbance in the line at the center of the surface of the object 7 indicates that the center of the object T is depressed toward the inside. In the case of FIG. 4, a depression of approximately 10 μm was read. In this embodiment, by moving the second diffraction grating 6, phase modulation can be easily imparted to the interference fringes B1 formed from the surface of the subject 7 without moving the subject T. The photoelectric conversion unit 9 operates the interference fringes B at predetermined time intervals to measure the distribution of light intensity signals including unnecessary signals. Thereafter, using the calculation formula explained in the embodiment, Fourier series expansion is applied to the function representing the distribution of the light intensity signal. and,
A sine term and a cosine term are calculated, and the ratio thereof is calculated to separate the phase signal of the interference pattern B+. The uneven state of the subject T is determined from this phase signal, and the shape is measured. According to the present invention, measurement can be performed even if the surface texture of the object is rough, and automatic measurement is now possible, so that a large number of objects can be measured with high accuracy in a short period of time.
第１図（ａｌ及び（ｂｌは各々この発明を示す平面図及
び側面図、第２図は干渉縞を位相変調させた波形、第３
図は本発明の第２回折格子の作用を表わす図、第４図は
被検体の３次元表示を示す図、第５図は従来の斜入射干
渉装置、第６図は第５図の作用を説明する図、第７図は
従来のフィゾー型干渉計、第８図は従来型の斜入射干渉
計装置。１：レーザ発振器 ２：発散レンズ ３：コリメータレ
ンズ ４：第１回折格子 ５：載置台６：第２回折格子
７：像面 ８：結像レンズα：回折光線 β：透過光
線 Ｔ：被検体第１図（ａ）第１図（ｂ）第図ら第図疋ｙｃｙｃ第４図第５図第図第図第図Figure 1 (al and (bl) are a plan view and a side view showing the present invention, respectively; Figure 2 is a waveform obtained by phase modulating interference fringes;
The figure shows the action of the second diffraction grating of the present invention, Fig. 4 shows a three-dimensional display of the object, Fig. 5 shows the conventional oblique incidence interference device, and Fig. 6 shows the action of Fig. 5. The diagrams for explanation, FIG. 7 is a conventional Fizeau type interferometer, and FIG. 8 is a conventional oblique incidence interferometer device. 1: Laser oscillator 2: Diverging lens 3: Collimator lens 4: First diffraction grating 5: Mounting table 6: Second diffraction grating 7: Image plane 8: Imaging lens α: Diffracted ray β: Transmitted ray T: Subject number Figure 1 (a) Figure 1 (b) Figure 4 Figure 5 Figure 5
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1267361AJPH03128411A (en) | 1989-10-13 | 1989-10-13 | Optical shape measuring device |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1267361AJPH03128411A (en) | 1989-10-13 | 1989-10-13 | Optical shape measuring device |
| Publication Number | Publication Date |
|---|---|
| JPH03128411Atrue JPH03128411A (en) | 1991-05-31 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1267361APendingJPH03128411A (en) | 1989-10-13 | 1989-10-13 | Optical shape measuring device |
| Country | Link |
|---|---|
| JP (1) | JPH03128411A (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003530564A (en)* | 2000-04-12 | 2003-10-14 | ナノ−オア テクノロジーズ インコーポレイテッド | Spatial and spectral wavefront analysis measurement method and apparatus |
| JP2009517871A (en)* | 2005-11-29 | 2009-04-30 | カール・ツァイス・エスエムティー・アーゲー | Projection irradiation system |
| US8472014B2 (en) | 2010-05-25 | 2013-06-25 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and refractive index distribution measuring apparatus |
| US8472013B2 (en) | 2008-12-25 | 2013-06-25 | Canon Kabushiki Kaisha | Refractive index distribution measurement method and apparatus that measure transmission wavefronts of a test object immersed in different media having refractive index lower than that of the test object |
| US8477297B2 (en) | 2010-12-03 | 2013-07-02 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and apparatus, and method of producing optical element thereof, that use multiple transmission wavefronts of a test object immersed in at least one medium having a different refractive index from that of the test object and multiple reference transmission wavefronts of a reference object having known shape and refractive index distribution |
| US8508725B2 (en) | 2009-12-07 | 2013-08-13 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and apparatus using position measurement and a reference object |
| US8525982B2 (en) | 2010-05-25 | 2013-09-03 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and refractive index distribution measuring apparatus |
| US8786863B2 (en) | 2009-03-25 | 2014-07-22 | Canon Kabushiki Kaisha | Transmitted wavefront measuring method, refractive-index distribution measuring method, and transmitted wavefront measuring apparatus that calculate a frequency distribution and obtain a transmitted wavefront of the object based on a primary frequency spectrum in the frequency distribution |
| CN104374380A (en)* | 2014-11-17 | 2015-02-25 | 中国航空工业第六一八研究所 | 3D assistant installation and correction method and device for large-scale instrument and equipment |
| CN105892257A (en)* | 2014-12-10 | 2016-08-24 | 青岛理工大学 | Method and device for recording hologram by sine structured light |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013064741A (en)* | 2000-04-12 | 2013-04-11 | Icos Vision Systems Nv | Method and apparatus for spatial and spectral wavefront analysis and measurement |
| JP2003530564A (en)* | 2000-04-12 | 2003-10-14 | ナノ−オア テクノロジーズ インコーポレイテッド | Spatial and spectral wavefront analysis measurement method and apparatus |
| JP2009517871A (en)* | 2005-11-29 | 2009-04-30 | カール・ツァイス・エスエムティー・アーゲー | Projection irradiation system |
| US8228485B2 (en) | 2005-11-29 | 2012-07-24 | Carl Zeiss Smt Gmbh | Projection illumination system |
| US8472013B2 (en) | 2008-12-25 | 2013-06-25 | Canon Kabushiki Kaisha | Refractive index distribution measurement method and apparatus that measure transmission wavefronts of a test object immersed in different media having refractive index lower than that of the test object |
| US8786863B2 (en) | 2009-03-25 | 2014-07-22 | Canon Kabushiki Kaisha | Transmitted wavefront measuring method, refractive-index distribution measuring method, and transmitted wavefront measuring apparatus that calculate a frequency distribution and obtain a transmitted wavefront of the object based on a primary frequency spectrum in the frequency distribution |
| US8508725B2 (en) | 2009-12-07 | 2013-08-13 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and apparatus using position measurement and a reference object |
| US8525982B2 (en) | 2010-05-25 | 2013-09-03 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and refractive index distribution measuring apparatus |
| US8472014B2 (en) | 2010-05-25 | 2013-06-25 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and refractive index distribution measuring apparatus |
| US8477297B2 (en) | 2010-12-03 | 2013-07-02 | Canon Kabushiki Kaisha | Refractive index distribution measuring method and apparatus, and method of producing optical element thereof, that use multiple transmission wavefronts of a test object immersed in at least one medium having a different refractive index from that of the test object and multiple reference transmission wavefronts of a reference object having known shape and refractive index distribution |
| CN104374380A (en)* | 2014-11-17 | 2015-02-25 | 中国航空工业第六一八研究所 | 3D assistant installation and correction method and device for large-scale instrument and equipment |
| CN105892257A (en)* | 2014-12-10 | 2016-08-24 | 青岛理工大学 | Method and device for recording hologram by sine structured light |
| CN105892257B (en)* | 2014-12-10 | 2019-09-03 | 青岛理工大学 | Method and device for recording hologram with sinusoidal structured light |
| Publication | Publication Date | Title |
|---|---|---|
| Creath | V phase-measurement interferometry techniques | |
| US3829219A (en) | Shearing interferometer | |
| US6271924B1 (en) | Noncontact acoustic optic scanning laser vibrometer for determining the difference between an object and a reference surface | |
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| Zhang et al. | Spatiotemporal phase unwrapping and its application in fringe projection fiber optic phase-shifting profilometry | |
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| Tverdokhleb et al. | A laser Doppler tomography method for investigating volume recording media |