JP2011215017A

JP2011215017A - Aspheric surface measuring apparatus

Info

Publication number: JP2011215017A
Application number: JP2010083870A
Authority: JP
Inventors: Masaaki Tomimizu; 政昭冨水; Souto Katsura; 宗涛葛
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2010-03-31
Filing date: 2010-03-31
Publication date: 2011-10-27

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus constituted of a structure preventing a breakdown of an application end of an interference optical system due to a collision between a sample stage for holding a sample and an application end of the optical system when measuring an aspheric surface of a measured surface with high accuracy.SOLUTION: A sample holder mechanism A and an interference optical mechanism B are installed so as to allow relative movement severally, with the holder mechanism A for holding the sample 10 while the optical mechanism B composed of the interference optical system 2 for performing optical interference measurement by emitting measurement light. A breakdown of the optical system 2 is prevented by providing a low-strength part 64 on the sample stage 6 for holding the measured object 10 on its end in the holder mechanism A, the strength part 64 absorbing a shock in colliding with the application end 2a of the optical system 2.

Description

本発明は、被測定物の非球面形状を有する被測定面（被検面）に測定光を照射し、被測定面からの戻り光と参照光との干渉により得られる干渉縞に基づき被測定面の形状を測定する非球面形状測定装置に関し、とくに被測定物を保持するサンプルステージの構造に関するものである。 The present invention irradiates measurement light onto a measurement surface (test surface) having an aspherical shape of a measurement object, and measures the measurement based on interference fringes obtained by interference between return light from the measurement surface and reference light. More particularly, the present invention relates to a structure of a sample stage that holds a measurement object.

従来、非球面形状の被測定面に球面波を照射して被測定面からの戻り光と参照光との干渉により形成される干渉縞に基づき、被測定面の局所的な形状を特定する手法が知られているが、このような手法により被測定面全域に対応した干渉縞を得ることは難しい。 Conventionally, a method for identifying a local shape of a measurement surface based on interference fringes formed by interference between return light from the measurement surface and reference light by irradiating aspherical measurement surface with a spherical wave However, it is difficult to obtain interference fringes corresponding to the entire surface to be measured by such a method.

そこで、干渉計または被測定面を測定光軸方向に順次移動させることにより、被測定面の径方向の部分領域毎に対応した干渉縞が順次生じるようにし、その各干渉縞を解析して被測定面の径方向の各部分領域の形状を求め、それらを繋ぎ合わせることにより被測定面全域の形状を特定する手法が知られている（下記特許文献１参照）。 Therefore, by sequentially moving the interferometer or the surface to be measured in the measurement optical axis direction, interference fringes corresponding to each partial region in the radial direction of the surface to be measured are sequentially generated. A technique is known in which the shape of each partial region in the radial direction of the measurement surface is obtained and the shape of the entire surface to be measured is specified by connecting them (see Patent Document 1 below).

一方、干渉計または被測定面を測定光軸と垂直な面内において順次移動させ、移動毎に被測定面の各部分領域に対応した干渉縞を縞解析可能な程度に拡大して撮像し、その各干渉縞を解析して被測定面の各部分領域の形状を求め、それらを繋ぎ合わせることにより被測定面全域の形状を特定する手法も知られている（下記特許文献２参照）。 On the other hand, the interferometer or the surface to be measured is sequentially moved in a plane perpendicular to the measurement optical axis, and the interference fringes corresponding to each partial region of the surface to be measured are enlarged and imaged to the extent that the fringe analysis can be performed for each movement. A technique is also known in which each interference fringe is analyzed to determine the shape of each partial region of the surface to be measured, and the shape of the entire surface to be measured is specified by connecting them (see Patent Document 2 below).

特開昭６２−１２６３０５号公報JP-A-62-126305 米国特許第６,９５６,６５７号明細書US Pat. No. 6,956,657

近年、非球面レンズの形状が複雑化しており、例えば、１つのレンズ面（被測定面）において、レンズ面の中心軸を中心に、凹形状となっている部分（凹面部）と凸形状となっている部分（凸面部）とを併せ持つような非球面形状のものが利用されるようになっている。このような凹面部と凸面部を有する被測定面の形状を光干渉測定により測定することは困難であるとされ、これまでは、光触針を用いた三次元形状測定により形状測定が行われていた。 In recent years, the shape of an aspheric lens has become complicated. For example, in one lens surface (surface to be measured), a concave portion (concave surface portion) and a convex shape centered on the central axis of the lens surface An aspherical shape having a portion (convex surface portion) that is formed is used. It is considered difficult to measure the shape of the surface to be measured having such a concave portion and a convex portion by optical interference measurement, and until now, shape measurement has been performed by three-dimensional shape measurement using an optical stylus. It was.

すなわち、一般的な光干渉測定法では、被測定面に照射された測定光が被測定面から再帰反射される（戻り光が元の光路を逆進する）領域のみで適正な干渉縞が得られるが、被測定面に照射される測定光が、測定光軸に沿って発散しながら進行する球面波か、測定光軸に沿って収束しながら進行する球面波のいずれかに固定されている上記特許文献１、２記載の手法では、被測定面からの戻り光の進行方向が凹面部と凸面部とで全く異なるため、凹面部と凸面部の両方の領域で共に適正な干渉縞を得ることができないのである。 That is, in a general optical interference measurement method, an appropriate interference fringe is obtained only in the region where the measurement light irradiated on the measurement surface is retroreflected from the measurement surface (the return light travels backward in the original optical path). However, the measurement light applied to the surface to be measured is fixed to either a spherical wave that travels while diverging along the measurement optical axis or a spherical wave that travels while converging along the measurement optical axis In the methods described in Patent Documents 1 and 2, since the traveling direction of the return light from the measured surface is completely different between the concave surface portion and the convex surface portion, appropriate interference fringes are obtained in both the concave surface portion and the convex surface portion. It cannot be done.

上記のような点から、本発明の発明者らは、例えば、上記のような凹面部と凸面部を有する非球面形状の測定においても、被測定物と干渉光学系とを相対的に３軸方向に移動可能であるとともに、被測定物をその中心軸の回りに回転させつつ光干渉測定を行い、さらに順次被測定物の中心軸と干渉光学系の測定光軸とのなす角度を変更しつつ同様に被測定物をその中心軸を中心として回転させつつ光干渉測定を行うことを繰り返し、その各干渉縞を解析して被測定面の各部分領域の形状を求め、それらを繋ぎ合わせることにより被測定面全域の形状を特定する手法が有効であることを研究結果として得ている。 From the above points, the inventors of the present invention, for example, relatively measure the object to be measured and the interference optical system in three axes in the measurement of the aspherical shape having the concave surface and the convex surface as described above. In addition to being able to move in the direction, the optical interference measurement is performed while rotating the object to be measured around its central axis, and the angle formed between the central axis of the object to be measured and the measuring optical axis of the interference optical system is sequentially changed. Similarly, repeat the optical interference measurement while rotating the object to be measured about its central axis, analyze each interference fringe to find the shape of each partial area of the surface to be measured, and connect them together As a result of research, we have found that the method of identifying the shape of the entire surface to be measured is effective.

その際に、上記のような被測定物を保持して非球面形状の中心軸の回りに回転させる被測定物の保持機構と、干渉光学系を保持してその測定光軸の方向を移動させる機構とを、それぞれ移動させて被測定面と干渉光学系との関係を所定の相対姿勢とする測定装置を設置した場合に、被測定物を保持するサンプルステージの移動軌跡と、干渉光学系の照射先端部の移動軌跡とが交差することから、測定のために被測定物をサンプルステージにセットする際もしくは測定後の被測定物を取り外すためにサンプルステージを移動させているときに、または、両者の相対姿勢を所定の状態に調整しているときなどにおいて、上記サンプルステージと干渉光学系の照射先端部とが衝突して破損が発生する恐れがある。 At that time, the measurement object holding mechanism that holds the measurement object as described above and rotates around the central axis of the aspherical shape, and the interference optical system is held and the direction of the measurement optical axis is moved. When a measuring device is installed in which the mechanism is moved so that the relationship between the surface to be measured and the interference optical system has a predetermined relative orientation, the movement locus of the sample stage that holds the object to be measured, and the interference optical system Since the movement trajectory of the irradiation tip intersects, when setting the measurement object on the sample stage for measurement or when moving the sample stage to remove the measurement object after measurement, or When the relative posture of the two is adjusted to a predetermined state, the sample stage and the irradiation tip of the interference optical system may collide with each other and damage may occur.

とくに、干渉光学系の照射先端部には対物レンズもしくは干渉のための参照光を得る基準板等の高価な光学素子が配設されており、これらの光学素子に衝突の影響による破損等が生起すると、部品が高価であるとともに、高い測定精度を確保するために高い部品精度および取付精度が要求されるために、その修理に多くの時間と費用がかかり、測定効率の点でも問題が生じる。 In particular, expensive optical elements such as an objective lens or a reference plate for obtaining reference light for interference are disposed at the irradiation tip of the interference optical system, and these optical elements are damaged due to the influence of a collision. Then, the parts are expensive, and high parts accuracy and mounting accuracy are required to ensure high measurement accuracy. Therefore, a lot of time and cost are required for the repair, and there is a problem in terms of measurement efficiency.

本発明は、このような事情に鑑みなされたものであり、被測定面の非球面形状を高精度に測定する際に、被測定物を保持するサンプルステージと干渉光学系の照射先端部との衝突による干渉光学系の照射先端部の破損を防止するようにした非球面形状測定装置を提供することを目的とする。 The present invention has been made in view of such circumstances, and when measuring the aspherical shape of the surface to be measured with high accuracy, the sample stage that holds the object to be measured and the irradiation tip of the interference optical system. It is an object of the present invention to provide an aspherical shape measuring apparatus that prevents damage to the irradiation tip of an interference optical system due to collision.

上記目的を達成するため、本発明の非球面形状測定装置は以下のように構成されている。 In order to achieve the above object, the aspherical shape measuring apparatus of the present invention is configured as follows.

すなわち、本発明に係る非球面形状測定装置は、非球面形状の被測定面を有する被測定物を保持する被測定物保持機構と、前記被測定物の被測定面に測定光を照射し該被測定面からの戻り光と参照光との干渉による干渉縞を取得する光干渉測定を行う干渉光学系を有する干渉光学機構とを備え、前記干渉縞に基づき前記被測定面の形状を測定する非球面形状測定装置であって、
前記被測定物保持機構および前記干渉光学機構は、それぞれ相対的に移動可能に設置されてなり、
前記被測定物保持機構は、前記被測定物を先端に保持するサンプルステージを備え、該サンプルステージに前記干渉光学系の照射先端部と衝突した際に衝撃を吸収する低強度部が設けられたことを特徴とする。 That is, an aspherical shape measuring apparatus according to the present invention includes a measured object holding mechanism that holds a measured object having an aspherical measured surface, and irradiates the measured surface of the measured object with measurement light. An interference optical mechanism having an interference optical system for performing an optical interference measurement for obtaining an interference fringe due to interference between return light from the surface to be measured and reference light, and measuring the shape of the surface to be measured based on the interference fringe An aspherical shape measuring device,
The measured object holding mechanism and the interference optical mechanism are installed to be relatively movable,
The object holding mechanism includes a sample stage that holds the object to be measured at the tip, and the sample stage is provided with a low-strength portion that absorbs an impact when the sample stage collides with the irradiation tip of the interference optical system. It is characterized by that.

また、本発明における前記低強度部は、切欠き構造で構成することが可能である。 In addition, the low-strength portion in the present invention can be configured with a notch structure.

前記サンプルステージは、前記被測定物とともに該被測定物の被測定面軸の回りに回転可能である回転ステージ部と、該回転ステージ部を回転中心位置が変更可能に保持する調整部とを備え、前記回転ステージ部が被測定物回転機構により回転駆動されるように構成してなり、前記回転ステージ部に前記低強度部を設置するのが好適である。 The sample stage includes a rotation stage unit that can rotate around the measurement surface axis of the object to be measured together with the object to be measured, and an adjustment unit that holds the rotation stage unit so that the rotation center position can be changed. It is preferable that the rotating stage unit is configured to be rotationally driven by a measured object rotating mechanism, and the low-strength unit is installed on the rotating stage unit.

また、本発明における前記被測定物保持機構は、前記被測定物を被測定面軸を中心として回転させる被測定物回転機構と、該被測定物回転機構を搭載し前記被測定面軸と直交方向または平行方向に直線移動させる第１スライド機構とを備え、
前記干渉光学機構は、前記干渉光学系を保持し該干渉光学系をその測定光軸と前記被測定面軸とのなす測定角度を変更可能に旋回させる光学系旋回機構と、該光学系旋回機構を搭載し前記第１スライド機構の移動方向と直交方向に直線移動させる第２スライド機構とを備えることが好ましい。 Further, the measurement object holding mechanism in the present invention includes a measurement object rotation mechanism that rotates the measurement object about a measurement surface axis, and a measurement object rotation mechanism that is mounted and orthogonal to the measurement surface axis. A first slide mechanism that linearly moves in a direction or parallel direction,
The interference optical mechanism holds the interference optical system and rotates the interference optical system so that the measurement angle between the measurement optical axis and the axis of the surface to be measured can be changed, and the optical system rotation mechanism And a second slide mechanism that linearly moves in a direction orthogonal to the moving direction of the first slide mechanism.

前記第１スライド機構および前記第２スライド機構をエアスライドで構成するのが好適である。 It is preferable that the first slide mechanism and the second slide mechanism are constituted by air slides.

前記被測定物回転機構および前記光学系旋回機構をエアスピンドルで構成するのが好適である。 It is preferable that the object rotation mechanism and the optical system turning mechanism are constituted by an air spindle.

なお、上記「被測定面軸」とは被測定物の被測定面における非球面形状の中心軸をいうものとする。 The “measurement surface axis” refers to the central axis of the aspherical shape on the measurement surface of the object to be measured.

本発明に係る非球面形状測定装置は、上述の構成を備えていることにより、以下のような作用効果を奏する。 The aspherical shape measuring apparatus according to the present invention has the following configuration and effects as follows.

すなわち、本発明の非球面形状測定装置においては、非球面形状の被測定面を有する被測定物を保持する被測定物保持機構と、被測定物の被測定面に測定光を照射し該被測定面からの戻り光と参照光との干渉による干渉縞を取得する光干渉測定を行う干渉光学系を有する干渉光学機構とを、それぞれ相対的に移動可能に設置してなり、上記被測定物保持機構における被測定物を先端に保持するサンプルステージに上記干渉光学系の照射先端部と衝突した際に衝撃を吸収する低強度部を設けたことにより、測定のために被測定物をサンプルステージにセットする際もしくは測定後の被測定物を取り外すためにサンプルステージを移動させているときに、または、両者の相対姿勢を所定の状態に調整しているときなどにおいて、上記サンプルステージと干渉光学系の照射先端部とが衝突した際には、上記被測定物を保持したサンプルステージの低強度部が変形または折損することなどにより衝撃を吸収し、干渉光学系の照射先端部が破損するなどのダメージを受けることが防止できる。したがって、干渉光学系の照射先端部に配設された対物レンズおよび基準板等の高価な光学素子に衝突の影響による破損等が生起することなく、修理に多くの時間と費用がかかることを未然に防止することができる。 That is, in the aspherical shape measuring apparatus of the present invention, the measured object holding mechanism for holding the measured object having the aspherical measured surface, and the measurement surface of the measured object are irradiated with the measurement light and the measured object is irradiated. An interference optical mechanism having an interference optical system for performing optical interference measurement for obtaining an interference fringe due to interference between the return light from the measurement surface and the reference light is installed so as to be relatively movable. A sample stage for holding the object to be measured in the holding mechanism is provided with a low-strength part that absorbs an impact when it collides with the irradiation tip of the interference optical system. When the sample stage is moved in order to remove the object to be measured after measurement, or when the relative posture of the two is adjusted to a predetermined state, the sample step is performed. When the sample collides with the irradiation tip of the interference optical system, the low-strength part of the sample stage holding the object to be measured is deformed or broken to absorb the impact, and the irradiation tip of the interference optical system. Can be prevented from being damaged. Therefore, it takes a lot of time and money to repair the optical elements such as the objective lens and the reference plate arranged at the irradiation tip of the interference optical system without causing damage due to the impact of the collision. Can be prevented.

また、上記低強度部を切欠き構造で構成すると、簡単な構造で低強度部が形成でき、衝突により変形したサンプルステージは、部品交換により短期間で修復でき、早期に測定を再開することが可能である。 In addition, if the low-strength part is configured with a notch structure, the low-strength part can be formed with a simple structure, and the sample stage deformed by a collision can be repaired in a short period of time by replacing parts, and measurement can be resumed early. Is possible.

また、本発明におけるサンプルステージを、被測定物とともに被測定面軸の回りに回転可能である回転ステージ部と、該回転ステージ部を回転中心位置が変更可能に保持する調整部とを備え、回転ステージ部が被測定物回転機構により回転駆動されるように構成してなり、前記回転ステージ部に低強度部を設置すると、被測定物を所定の特性で回転作動および移動が行え、測定機能および測定精度を確保しつつ上記低強度部による干渉光学系の照射先端部の破損防止を図ることができる。 In addition, the sample stage according to the present invention includes a rotating stage unit that can rotate around the measurement surface axis together with the object to be measured, and an adjusting unit that holds the rotating stage unit so that the rotation center position can be changed. The stage unit is configured to be rotationally driven by a measured object rotation mechanism. When a low-strength unit is installed on the rotary stage unit, the measured object can be rotated and moved with predetermined characteristics, and the measurement function and It is possible to prevent the irradiation tip of the interference optical system from being damaged by the low-strength part while ensuring measurement accuracy.

また、保持した被測定物を被測定面軸を中心として回転させる被測定物回転機構および該被測定物回転機構を搭載し被測定面軸と直交方向または平行方向に直線移動させる第１スライド機構を備える被測定物保持機構と、被測定面に測定光を照射して光干渉測定を行う干渉光学系を保持し該干渉光学系をその測定光軸と被測定面軸とのなす測定角度を変更可能に旋回させる光学系旋回機構および該光学系旋回機構を搭載し第１スライド機構の移動方向と直交方向に直線移動させる第２スライド機構を備える干渉光学機構とを備えるように構成すると、２軸方向に設けた第１スライド機構と第２スライド機構を別途に作動させて、それぞれの移動負荷を軽減することで移動精度を確保して測定精度を高めることができるとともに、両スライド機構を別々に配置したことで一体に構成した場合に比べて構成のコンパクト化が図れ、また、一体化構造において必要とされる周辺部材の高剛性化による精度向上を不要にし、低剛性構造で十分な測定精度を確保でき、しかも、２軸方向の回転動作を被測定物回転機構と光学系旋回機構とに分離して別途に作動させて、それぞれの移動負荷を軽減することで移動精度を確保して測定精度を高めることができ、微小非球面レンズ等の形状測定を高精度に実現できる。 Further, a measured object rotating mechanism that rotates the measured object held about the measured surface axis, and a first slide mechanism that is mounted with the measured object rotating mechanism and moves linearly in a direction perpendicular to or parallel to the measured surface axis. A measurement object holding mechanism, and an interference optical system that performs optical interference measurement by irradiating the measurement surface with measurement light, and measuring the angle between the measurement optical axis and the measurement surface axis. An optical system turning mechanism that turns in a changeable manner and an interference optical mechanism that includes the optical system turning mechanism and that has a second slide mechanism that moves linearly in a direction orthogonal to the moving direction of the first slide mechanism are provided. The first slide mechanism and the second slide mechanism provided in the axial direction are separately operated to reduce the respective movement loads, thereby ensuring the movement accuracy and increasing the measurement accuracy. By arranging them separately, the structure can be made compact compared to the case where they are integrated, and it is not necessary to improve accuracy by increasing the rigidity of the peripheral members required in the integrated structure. Measurement accuracy can be ensured, and the rotational motion in two axes is separated into the measured object rotation mechanism and the optical swivel mechanism and operated separately to reduce the respective movement load and ensure the movement accuracy. As a result, the measurement accuracy can be increased, and the shape measurement of a minute aspheric lens or the like can be realized with high accuracy.

また、上記第１スライド機構および第２スライド機構をエアスライドで構成すると、気体を潤滑膜とすることで使用に伴う摩耗が発生せず、被測定物および干渉光学系の移動精度すなわち測定精度を長期間にわたって良好に維持することができる。 Further, when the first slide mechanism and the second slide mechanism are constituted by air slides, wear due to use is not generated by using a gas as a lubricating film, and the movement accuracy of the measured object and the interference optical system, that is, the measurement accuracy is improved. It can be maintained well over a long period of time.

同様に、上記被測定物回転機構および光学系旋回機構をエアスピンドルで構成すると、使用に伴う摩耗が発生せず、被測定物の回転精度および測定角度の変更精度すなわち測定精度を長期間にわたって良好に維持することができる。 Similarly, if the measured object rotation mechanism and the optical system turning mechanism are configured with an air spindle, wear due to use does not occur, and the measured object rotation accuracy and measurement angle change accuracy, that is, measurement accuracy is good over a long period of time. Can be maintained.

本発明の一実施形態に係る非球面形状測定装置における被測定物保持機構と干渉光学機構との先端衝突状態を示す要部平面図である。It is a principal part top view which shows the front-end | tip collision state of the to-be-measured object holding | maintenance mechanism and interference optical mechanism in the aspherical surface shape measuring apparatus which concerns on one Embodiment of this invention. 本発明の一実施形態に係る非球面形状測定装置の概略構成を示す斜視図である。It is a perspective view which shows schematic structure of the aspherical surface shape measuring apparatus which concerns on one Embodiment of this invention. 図２のカバーを省略した概略正面図である。It is the schematic front view which abbreviate | omitted the cover of FIG. 図３の定盤を省略した平面図である。FIG. 4 is a plan view in which the surface plate of FIG. 3 is omitted. 図４の一例の移動状態を示す平面図である。It is a top view which shows the movement state of an example of FIG. 図２の実施形態における光学系および制御系の構成を示す機構図である。FIG. 3 is a mechanism diagram showing configurations of an optical system and a control system in the embodiment of FIG. 2. 一例の測定動作を示す動作フロー図である。It is an operation | movement flowchart which shows an example measurement operation | movement.

以下、本発明の実施形態について、図面を参照しながら詳細に説明する。なお、図６の機構図では、図１〜図５に対して各部材の大きさや部材間の距離等を適宜変更して示してあり、詳細な形状や構造を示すものではない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the mechanism diagram of FIG. 6, the size of each member, the distance between the members, and the like are appropriately changed with respect to FIGS. 1 to 5, and the detailed shape and structure are not shown.

図２〜図６に示す本実施形態の非球面形状測定装置１は、被測定物１０（非球面レンズ）が有する回転対称な被測定面１０ａ（図６参照）の非球面形状を測定解析するものであり、被測定面１０ａに測定光を照射し該被測定面１０ａからの戻り光を参照光と合成して干渉光を得る干渉光学系２と、得られた干渉光により形成される干渉縞を撮像する第１撮像系３および第２撮像系４と、撮像された干渉縞を解析して被測定面１０ａの形状を求める測定解析系５（図６参照）と、被測定物１０を保持姿勢が手動調整可能であるサンプルステージ６と、を備えてなる。 The aspherical shape measuring apparatus 1 of the present embodiment shown in FIGS. 2 to 6 measures and analyzes the aspherical shape of the rotationally symmetric measured surface 10a (see FIG. 6) of the measured object 10 (aspherical lens). The interference optical system 2 that irradiates the measurement surface 10a with measurement light and combines the return light from the measurement surface 10a with reference light to obtain interference light, and interference formed by the obtained interference light A first image pickup system 3 and a second image pickup system 4 for picking up the fringes, a measurement analysis system 5 (see FIG. 6) for analyzing the picked-up interference fringes to obtain the shape of the measurement target surface 10a, and the device under test 10 And a sample stage 6 whose holding posture can be manually adjusted.

そして、上記サンプルステージ６を含み、保持姿勢が調整された被測定物１０を被測定面軸Ｓの回りに回転させる第１エアスピンドル７０（被測定物回転機構）、およびＸ方向（被測定面軸Ｓと直交する方向）に直線（スライド）移動させる第１のエアスライド７（第１スライド機構）を備えた被測定物保持機構Ａが構成される。また、上記干渉光学系２、第１撮像系３および第２撮像系４を含み、これらを鉛直方向であるＺ方向を中心として旋回させる第２エアスピンドル８０（光学系旋回機構）、およびＹ方向（被測定面軸Ｓと平行方向）に直線（スライド）移動させる第２のエアスライド８（第２スライド機構）を備えた干渉光学機構Ｂが構成される。 Then, a first air spindle 70 (measuring object rotating mechanism) that rotates the object to be measured 10 including the sample stage 6 and whose holding posture is adjusted around the surface axis S to be measured, and an X direction (surface to be measured) A measurement object holding mechanism A including a first air slide 7 (first slide mechanism) that moves in a straight line (slide) in a direction orthogonal to the axis S is configured. In addition, the interference optical system 2, the first imaging system 3, and the second imaging system 4, including a second air spindle 80 (optical system pivoting mechanism) that pivots around the Z direction that is the vertical direction, and the Y direction An interference optical mechanism B including a second air slide 8 (second slide mechanism) that moves in a straight line (slide) in the direction parallel to the measurement surface axis S is configured.

＜被測定物保持機構Ａ＞
上記サンプルステージ６は、図３、図４および図６に示すように、移動ベースとなる基台部６０と、該基台部６０に取り付けられた調整部６１と、該調整部６１に回転軸Ｅと被測定面軸Ｓ（図６参照）との位置調整可能に設置され、後述の第１エアスピンドル７０（被測定物回転機構）を介して回転可能に保持された回転ステージ部６２と、該回転ステージ部６２の先端に設置された被測定物ホルダー６３とを備え、該被測定物ホルダー６３に被測定物１０が保持される。 <Measurement holding mechanism A>
As shown in FIGS. 3, 4, and 6, the sample stage 6 includes a base portion 60 that serves as a movement base, an adjustment portion 61 that is attached to the base portion 60, and a rotating shaft that is attached to the adjustment portion 61. A rotary stage unit 62 installed so as to be capable of adjusting the position of E and the surface axis S to be measured (see FIG. 6), and rotatably held via a first air spindle 70 (measuring object rotation mechanism) described later; A measurement object holder 63 installed at the tip of the rotary stage unit 62 is provided, and the measurement object 10 is held by the measurement object holder 63.

そして、上記サンプルステージ６における回転ステージ部６２は、例えば、アルミニウム系材料により棒状に形成され、該回転ステージ部６２の途中には、図１にも示すように、一部の径が細くなるように切欠き構造に構成された低強度部６４が設けられている。この低強度部６４は、干渉光学系２の照射先端部２ａと衝突した際に折損もしくは変形して衝撃を吸収し、照射先端部２ａにダメージが発生するのを阻止する。 The rotary stage portion 62 in the sample stage 6 is formed in a rod shape by, for example, an aluminum-based material, and a part of the diameter is reduced in the middle of the rotary stage portion 62 as shown in FIG. A low-strength portion 64 having a notch structure is provided. This low-strength portion 64 breaks or deforms when it collides with the irradiation tip portion 2a of the interference optical system 2 and absorbs the impact, thereby preventing the irradiation tip portion 2a from being damaged.

つまり、図１には、後述の移動機構を有する干渉光学機構Ｂの作動に応じて、干渉光学系２がその測定光軸Ｌが所定角度に調整され、図５でＹ方向に移動された状態で、サンプルステージ６が上方に移動した際に、このサンプルステージ６の回転ステージ部６２の先端部が、上記干渉光学系２の照射先端部２ａに衝突した状態を示している。この衝突に伴い、回転ステージ部６２の先端部に矢印で示される力Ｆが作用すると、上記切欠き構造により径が細く、曲げ強度が低くなるように設けられた低強度部６４が図で下向きに変形し、その変形量が大きくなると折損して衝撃を吸収するものであり、干渉光学系２の照射先端部２ａ側には変形および破損が生じないように、とくに内部に配置されている光学素子に影響が及ばないようにしている。 That is, FIG. 1 shows a state in which the measurement optical axis L of the interference optical system 2 is adjusted to a predetermined angle and moved in the Y direction in FIG. 5 according to the operation of the interference optical mechanism B having a moving mechanism described later. Thus, when the sample stage 6 moves upward, the tip of the rotating stage 62 of the sample stage 6 collides with the irradiation tip 2a of the interference optical system 2. When a force F indicated by an arrow is applied to the tip of the rotary stage unit 62 due to this collision, the low strength portion 64 provided so as to have a small diameter and a low bending strength due to the notch structure is directed downward in the figure. When the amount of deformation increases, it breaks and absorbs the impact, and the optically disposed optical element 2 is particularly arranged so that no deformation or damage occurs on the irradiation tip 2a side of the interference optical system 2. The element is not affected.

上記調整部６１は、回転ステージ部６２すなわち被測定物ホルダー６３の回転中心位置がその平面内でＸ方向およびＺ方向に手動で調整可能であるとともに、回転中心の傾きがθＸ方向θＺ方向に手動で調整可能であり、後述の干渉光学系２の測定光軸Ｌとの初期調整を行うように構成されている。その調整により、初期状態において、被測定物１０の被測定面軸Ｓと調整部６１の回転軸Ｅとが一致するように、さらに、干渉光学系２の測定光軸Ｌとが一致するように設定してから測定が開始される。 The adjusting unit 61 is capable of manually adjusting the rotation center position of the rotary stage unit 62, that is, the workpiece holder 63, in the X direction and the Z direction within the plane, and the inclination of the rotation center is manually adjusted in the θX direction and the θZ direction. The initial adjustment with the measurement optical axis L of the interference optical system 2 to be described later is performed. By the adjustment, in the initial state, the measurement surface axis S of the DUT 10 and the rotation axis E of the adjustment unit 61 coincide with each other, and further, the measurement optical axis L of the interference optical system 2 coincides. Measurement starts after setting.

また、上記サンプルステージ６に保持された被測定物１０は、第１エアスピンドル７０（被測定物回転機構）によって測定時に回転作動されるとともに、測定角度を変更する際に第１エアスライド７（第１スライド機構）によってＸ方向位置が移動操作される。つまり、前記基台部６０に第１エアスピンドル７０が調整部６１と同軸に取り付けられ、その回転駆動力が上記回転ステージ部６２に伝達され、保持した被測定物１０とともに回転ステージ部６２を回転作動させるように設けられている。 The object to be measured 10 held on the sample stage 6 is rotated during measurement by the first air spindle 70 (measuring object rotation mechanism), and the first air slide 7 ( The position in the X direction is moved by the first slide mechanism. In other words, the first air spindle 70 is attached to the base portion 60 coaxially with the adjusting portion 61, and the rotational driving force is transmitted to the rotary stage portion 62 to rotate the rotary stage portion 62 together with the held object 10 to be measured. It is provided to operate.

さらに、上記基台部６０が第１エアスライド７の摺動台７３に搭載され、該摺動台７３が定盤９（防振台）にＸ方向に敷設されたガイド７４に摺動可能に載置されている。この第１エアスライド７は、静圧気体軸受けであり摺動台７３に加圧エアが導入され、ガイド７４との隙間に気体潤滑膜が生成されて摺動台７３がガイド７４から浮上し、不図示のモータの駆動によって摺動台７３をガイド７４に沿って移動操作可能に設けられている。ガイド７４の位置は不図示のエンコーダにより検出され、解析制御装置５０によってＸ方向位置が制御される。 Further, the base portion 60 is mounted on a slide base 73 of the first air slide 7 so that the slide base 73 can slide on a guide 74 laid in the X direction on the surface plate 9 (anti-vibration base). It is placed. The first air slide 7 is a static pressure gas bearing, and pressurized air is introduced into the slide base 73, a gas lubricating film is generated in the gap with the guide 74, and the slide base 73 floats from the guide 74. The sliding base 73 is provided so as to be movable along the guide 74 by driving a motor (not shown). The position of the guide 74 is detected by an encoder (not shown), and the position in the X direction is controlled by the analysis control device 50.

また、上記第１エアスピンドル７０は、図示してないが、ケース内に回転軸が気体潤滑膜を介して回転可能に保持され、その回転軸にはサーボモータが設置されて回転駆動される公知の構造であり、回転位置（回転量）はエンコーダにより検出され、解析制御装置５０によって回転位置が制御される。 The first air spindle 70 is not shown in the figure, but a rotary shaft is rotatably held in the case through a gas lubrication film, and a servo motor is installed on the rotary shaft and is driven to rotate. The rotational position (rotation amount) is detected by the encoder, and the rotational position is controlled by the analysis control device 50.

＜干渉光学機構Ｂ＞
干渉光学系２は、図６に示すように、フィゾータイプの光学系配置をなすものであり、高可干渉性の光束を出力する光源部２０と、該光源部２０からの出力光のビーム径を拡大するビーム径拡大レンズ２１と、後述の干渉光を図中上方に向けて反射する光束分岐光学素子２２と、該光束分岐光学素子２２を透過した光束をコリメートするコリメータレンズ２３と、該コリメータレンズ２３からの平面波の一部を参照基準平面２４ａにおいて再帰反射して参照光となし、その余を測定光軸Ｌに沿って進行する測定光として照射する平面基準板２４と、これらの光学素子を収納した鏡筒２５とを備えてなる。また、上記平面基準板２４は、ピエゾ素子２９を備えたフリンジスキャンアダプタ２８に保持され、フリンジスキャン計測等を実施する際に測定光軸Ｌ方向に微動するように構成されている。 <Interference optical mechanism B>
As shown in FIG. 6, the interference optical system 2 has a Fizeau type optical system arrangement, and includes a light source unit 20 that outputs a highly coherent light beam, and a beam diameter of output light from the light source unit 20. A beam diameter enlarging lens 21, a beam branching optical element 22 for reflecting interference light described later upward in the figure, a collimator lens 23 for collimating the light beam transmitted through the beam branching optical element 22, and the collimator A part of the plane wave from the lens 23 is retroreflected on the reference standard plane 24a to form reference light, and the rest is irradiated as measurement light traveling along the measurement optical axis L, and these optical elements. And a lens barrel 25 in which is stored. The plane reference plate 24 is held by a fringe scan adapter 28 provided with a piezo element 29, and is configured to finely move in the direction of the measurement optical axis L when performing fringe scan measurement or the like.

上記干渉光学系２の照射先端部２ａには、上記のように平面基準板２４が設置されるほか、必要に応じて対物レンズなどの光学素子が設置される。 At the irradiation tip 2a of the interference optical system 2, the flat reference plate 24 is installed as described above, and an optical element such as an objective lens is installed as necessary.

なお、図６は説明用に大きさを変更して示しており、とくに測定光として被測定面１０ａに照射される光束の径は被測定面１０ａの外径に対して非常に小さく、その照射測定範囲は部分的であり、後述のように被測定面１０ａは同心円状に複数の輪帯状（径の異なるリング状）に分割された測定領域に設定される。 Note that FIG. 6 shows the size changed for explanation. In particular, the diameter of the light beam applied to the measurement surface 10a as measurement light is very small with respect to the outer diameter of the measurement surface 10a. The measurement range is partial, and the measurement surface 10a is set in a measurement region that is concentrically divided into a plurality of annular zones (ring shapes having different diameters) as will be described later.

上記第２撮像系４は、主に、被測定面１０ａが初期姿勢（測定光軸Ｌと回転軸Ｅとが互いに一致し、かつ被測定面軸Ｓが測定光軸Ｌと平行となる状態の姿勢）をとるときに撮像を行うものであり、上記干渉光学系２の光束分岐光学素子２２により図中上方に向けて反射され、第１撮像系３に向けて干渉光を反射するための光束分岐光学素子３４を透過した干渉光を集光する結像レンズ４０と、エリアＣＣＤやＣＭＯＳ等からなる２次元イメージセンサ４２を有してなる撮像カメラ４１と、これらの光学素子を収納した鏡筒４５とを備えてなり、結像レンズ４０により２次元イメージセンサ４２上に形成された干渉縞の画像データを取得するように構成されている。 The second imaging system 4 is mainly configured so that the measured surface 10a is in an initial posture (the measurement optical axis L and the rotation axis E coincide with each other and the measured surface axis S is parallel to the measurement optical axis L). A light beam for reflecting the interference light toward the first image pickup system 3 by being reflected upward by the light beam branching optical element 22 of the interference optical system 2. An imaging lens 40 for condensing the interference light transmitted through the branch optical element 34, an imaging camera 41 having a two-dimensional image sensor 42 composed of an area CCD, a CMOS, and the like, and a lens barrel containing these optical elements 45, and is configured to acquire image data of interference fringes formed on the two-dimensional image sensor 42 by the imaging lens 40.

また、上記第１撮像系３は、被測定面１０ａの回転時に撮像を行うものであり、上記光束分岐光学素子３４により反射され図中右方に進行する干渉光を集光する結像レンズ３０と、ラインＣＣＤやＣＭＯＳ等からなる１次元イメージセンサ３２を有してなる撮像カメラ３１と、これらの光学素子を収納した鏡筒３５とを備えてなり、結像レンズ３０により１次元イメージセンサ３２上に形成された干渉縞の画像データを取得するように構成されている。 The first image pickup system 3 picks up an image when the surface to be measured 10a rotates, and forms an imaging lens 30 that collects the interference light reflected by the light beam splitting optical element 34 and traveling rightward in the drawing. And an imaging camera 31 having a one-dimensional image sensor 32 composed of a line CCD, a CMOS, and the like, and a lens barrel 35 housing these optical elements. It is configured to acquire image data of the interference fringes formed on the top.

なお、上記干渉光学系２の鏡筒２５は水平方向（測定初期状態でＹ方向）に配置され、該鏡筒２５の上部に第２撮像系４の鏡筒４５が縦方向（Ｚ方向）に立設されるとともに、鏡筒２５と平行に第１撮像系３の鏡筒３５が設置され、各鏡筒２５，３５，４５は相互に固定され、一体的に移動するようになっている。 The lens barrel 25 of the interference optical system 2 is arranged in the horizontal direction (Y direction in the initial measurement state), and the lens barrel 45 of the second imaging system 4 is arranged in the vertical direction (Z direction) above the lens barrel 25. The lens barrel 35 of the first imaging system 3 is installed in parallel with the lens barrel 25, and the lens barrels 25, 35, and 45 are fixed to each other and moved integrally.

上記干渉光学系２（第１撮像系３および第２撮像系４）は、第２エアスピンドル８０（光学系旋回機構）によって測定角度の変更時に旋回作動されるとともに、測定角度を変更する際に第２エアスライド８（第２スライド機構）によってＹ方向位置が移動操作される。つまり、回転軸がＺ方向となるように縦向きに設置された第２エアスピンドル８０の上端に、前記干渉光学系２の鏡筒２５が搭載されている。そして、該第２エアスピンドル８０は保持部８１に保持され、その回転駆動力が上記鏡筒２５に伝達され、干渉光学系２（第１撮像系３および第２撮像系４）をＺ軸を中心として旋回作動（θＺ）させるように設けられている。 The interference optical system 2 (the first imaging system 3 and the second imaging system 4) is turned when the measurement angle is changed by the second air spindle 80 (optical system turning mechanism), and when the measurement angle is changed. The position in the Y direction is moved by the second air slide 8 (second slide mechanism). That is, the lens barrel 25 of the interference optical system 2 is mounted on the upper end of the second air spindle 80 that is installed vertically so that the rotation axis is in the Z direction. The second air spindle 80 is held by the holding portion 81, and its rotational driving force is transmitted to the lens barrel 25, and the interference optical system 2 (the first imaging system 3 and the second imaging system 4) is moved along the Z axis. It is provided so as to be pivoted (θZ) as the center.

さらに、上記保持部８１が第２エアスライド８の基台部８２の中間位置（図４参照）に搭載されている。該基台部８２の図４で上方の一端は第２エアスライド８の摺動台８３に搭載され、該摺動台８３は定盤９（防振台）に設置されたＹ方向（第１エアスライド７の移動方向に直交する方向）に敷設されたガイド８４に摺動可能に載置されている。上記基台部８２の図４で下方の他端はエアブッシュ８６によって摺動台８３が水平となるように所定の高さに保持されている。該エアブッシュ８６は導入された圧縮空気によって底面が定盤９の上面に対して気体潤滑膜を介して浮上するように構成され、定盤９上を低摩擦状態で摺動する。 Further, the holding portion 81 is mounted at an intermediate position of the base portion 82 of the second air slide 8 (see FIG. 4). The upper end of the base 82 in FIG. 4 is mounted on a slide base 83 of the second air slide 8, and the slide base 83 is installed in the Y direction (the first direction) installed on the surface plate 9 (vibration isolation base). It is slidably mounted on a guide 84 laid in a direction orthogonal to the moving direction of the air slide 7. The other lower end of the base 82 in FIG. 4 is held at a predetermined height by the air bush 86 so that the slide base 83 is horizontal. The air bushing 86 is configured such that the bottom surface of the air bushing 86 is floated with respect to the upper surface of the surface plate 9 through a gas lubrication film by the introduced compressed air, and slides on the surface plate 9 in a low friction state.

そして、第２エアスライド８は、上記第１エアスライド７と同様に摺動台８３に加圧エアが導入され、ガイド８４との隙間に気体潤滑膜が生成されて摺動台８３がガイド８４から浮上し、不図示のモータの駆動によって摺動台８３をガイド８４に沿って移動操作可能に設けられている。このガイド８４の位置は不図示のエンコーダによって検出され、解析制御装置５０によってＹ方向位置が制御される。 Then, in the second air slide 8, the pressurized air is introduced into the sliding table 83 in the same manner as the first air slide 7, and a gas lubrication film is generated in the gap between the guide 84 and the sliding table 83 becomes the guide 84. The sliding table 83 is provided so as to be movable along the guide 84 by driving a motor (not shown). The position of the guide 84 is detected by an encoder (not shown), and the position in the Y direction is controlled by the analysis control device 50.

また、上記第２エアスピンドル８０は、図示してないが、第１エアスピンドル７０と同様にケース内に回転軸が気体潤滑膜を介して回転可能に保持され、その回転軸にはサーボモータが設置されて回転駆動される公知の構造であり、回転位置（回転量）はエンコーダによって検出され、解析制御装置５０により回転位置が制御される。この第２エアスピンドル８０は、干渉光学系２の鏡筒２５を保持している部分が基台部８２および摺動台８３に対して昇降移動可能であり、下方に設置された昇降アクチュエータ８７の駆動によって昇降移動され、その昇降位置がエンコーダによって検出され、解析制御装置５０によりＺ方向位置が制御される。 Although the second air spindle 80 is not shown, a rotating shaft is rotatably held in the case through a gas lubrication film in the same manner as the first air spindle 70, and a servo motor is attached to the rotating shaft. It is a known structure that is installed and rotationally driven. The rotational position (rotation amount) is detected by an encoder, and the rotational position is controlled by the analysis control device 50. In the second air spindle 80, the portion of the interference optical system 2 that holds the lens barrel 25 can be moved up and down with respect to the base 82 and the slide base 83. It is moved up and down by the drive, its lift position is detected by the encoder, and the position in the Z direction is controlled by the analysis control device 50.

上記被測定物保持機構Ａおよび干渉光学機構Ｂの動作により、上記被測定面１０ａは、干渉光学系２の測定光軸Ｌに対する相対姿勢（測定光軸Ｌに対する傾き角度およびＸ，Ｙ，Ｚ方向位置）を自在に変更し得るようになっている。 Due to the operations of the measurement object holding mechanism A and the interference optical mechanism B, the measurement target surface 10a is positioned relative to the measurement optical axis L of the interference optical system 2 (inclination angle with respect to the measurement optical axis L and X, Y, and Z directions). (Position) can be changed freely.

上記被測定物保持機構Ａおよび干渉光学機構Ｂは、図２に示すように、定盤９上に設置され、この定盤９は支持脚９１上に設置された防振台９２に載置され、上部空間はカバー９５によって覆われ、測定部分の急激な温度変化および湿度変化に伴う測定精度の低下を防止している。該カバー９５には、前扉９５ａおよび上扉９５ｂが設けられ、被測定物１０の交換時等に開いて測定者による作業が行えるようにしている。 As shown in FIG. 2, the measurement object holding mechanism A and the interference optical mechanism B are installed on a surface plate 9, and the surface plate 9 is placed on a vibration isolation table 92 installed on a support leg 91. The upper space is covered with a cover 95 to prevent a decrease in measurement accuracy due to a sudden temperature change and humidity change in the measurement part. The cover 95 is provided with a front door 95a and an upper door 95b, which are opened when the object to be measured 10 is exchanged, etc., and can be operated by a measurer.

なお、前記干渉光学機構Ｂにおける昇降アクチュエータ８７は、定盤９より下方に延びて設置されているものであり、この場合には定盤９に昇降アクチュエータ８７が移動可能な長孔（不図示）が開口形成され、干渉光学系２のＹ方向移動を許容するように設けられている。 The lifting actuator 87 in the interference optical mechanism B is installed extending downward from the surface plate 9, and in this case, a long hole (not shown) through which the lifting actuator 87 can move on the surface plate 9. Is formed so as to allow the interference optical system 2 to move in the Y direction.

＜測定解析系５＞
上記測定解析系５は、１次元イメージセンサ３２および２次元イメージセンサ４２により取得された干渉縞の画像データの信号を受け、その画像データに基づき被測定面１０ａの形状データおよび被測定面１０ａの面偏芯量を演算解析するとともに、図７に基づき後述するような測定動作を制御するために、被測定物保持機構Ａの第１エアスライド７、第１エアスピンドル７０および上記干渉光学機構Ｂの第２エアスライド８、第２エアスピンドル８０、昇降アクチュエータ８７に駆動信号ａ〜ｆ（図６参照）を出力し、その駆動を制御するもので、コンピュータ等からなる解析制御装置５０と、該解析制御装置５０による解析結果や画像を表示する表示装置５１と、キーボードやマウス等からなる入力装置５２とを備えてなる。 <Measurement analysis system 5>
The measurement analysis system 5 receives the signal of the interference fringe image data acquired by the one-dimensional image sensor 32 and the two-dimensional image sensor 42, and based on the image data, the shape data of the measured surface 10a and the measured surface 10a. In order to calculate and analyze the surface eccentricity and to control a measurement operation as will be described later based on FIG. 7, the first air slide 7, the first air spindle 70 and the interference optical mechanism B of the measured object holding mechanism A are used. Drive signals a to f (see FIG. 6) are output to the second air slide 8, the second air spindle 80, and the lift actuator 87 to control the drive thereof, and the analysis control device 50 including a computer or the like, It comprises a display device 51 for displaying the analysis results and images by the analysis control device 50, and an input device 52 such as a keyboard or a mouse.

そして、上記被測定物１０は、被測定面軸Ｓを中心とした回転対称な被測定面１０ａを有しており、該被測定面１０ａは、上記干渉光学系２側に凹となる凹面部と、凸となる凸面部と、凹面部と凸面部との境界部分に位置する軸外停留点部とを有し、その形状に応じて、被測定面１０ａの設計データに基づき、該被測定面１０ａ上に、該被測定面１０ａを径方向に輪帯状（径の異なる同心円リング状）に分割してなる複数の測定領域を設定するものである。 The measured object 10 has a measured surface 10a that is rotationally symmetric about the measured surface axis S, and the measured surface 10a is a concave surface that is concave on the interference optical system 2 side. And a convex surface portion that is convex, and an off-axis stationary point portion that is located at the boundary portion between the concave surface portion and the convex surface portion, and based on the design data of the measured surface 10a, the measured device On the surface 10a, a plurality of measurement regions are set by dividing the surface 10a to be measured into a ring shape (concentric ring shape with different diameters) in the radial direction.

上記被測定面１０ａが初期姿勢をとるときに第２撮像系４の２次元イメージセンサ４２により撮像された干渉縞画像に基づき、測定光軸Ｌと被測定面軸Ｓとが一致するように調整部６１を手動調整するものである。 Based on the interference fringe image captured by the two-dimensional image sensor 42 of the second imaging system 4 when the measured surface 10a assumes the initial posture, the measurement optical axis L and the measured surface axis S are adjusted to coincide with each other. The unit 61 is manually adjusted.

また、解析制御装置５０は、測定光軸Ｌの被測定面１０ａとの交点位置が、設定された複数の測定領域上に順次移動するように、かつ移動毎に測定光軸Ｌが交点位置における被測定面１０ａの接平面と垂直に交わるように、被測定面１０ａに対する測定光軸Ｌの相対姿勢を、移動部分が相互に干渉することなく第１エアスライド７、第２エアスライド８、第２エアスピンドル８０、昇降アクチュエータ８７の駆動を制御する。さらに、上記第１エアスピンドル７０の作動により、被測定面１０ａを回転させつつ第１撮像系３の１次元イメージセンサ３２により撮像された各測定領域別干渉縞と、該各干渉縞が撮像されたときの被測定面１０ａの姿勢および回転角度の各データとに基づき、上記複数の測定領域の各々に対応した各形状情報を求めるとともに、各形状情報を繋ぎ合わせることにより分割した複数の測定領域を互いに合成して被測定面全域の形状情報を求めるものである。 In addition, the analysis control device 50 allows the measurement optical axis L at the intersection position so that the intersection position of the measurement optical axis L with the measurement target surface 10a sequentially moves on the plurality of set measurement areas. The relative orientation of the measurement optical axis L with respect to the surface to be measured 10a is set so that the moving portion does not interfere with each other so that the moving portion does not interfere with each other so that the tangent plane of the surface to be measured 10a intersects perpendicularly. (2) The drive of the air spindle 80 and the lifting actuator 87 is controlled. Further, by the operation of the first air spindle 70, the interference fringes for each measurement region imaged by the one-dimensional image sensor 32 of the first imaging system 3 while the surface to be measured 10a is rotated are imaged. A plurality of measurement regions divided by joining the shape information together with the shape information corresponding to each of the plurality of measurement regions based on the posture and rotation angle data of the measured surface 10a Are combined with each other to obtain shape information of the entire surface to be measured.

次に、本実施形態における非球面形状測定装置１の測定手順について図７に基づいて説明する。 Next, the measurement procedure of the aspheric surface shape measuring apparatus 1 in the present embodiment will be described based on FIG.

まず、電源がオンとされてから、被測定物１０をセットするために初期移動操作を行う。ステップＳ１で左側の第１エアスライド７を動作させて、サンプルステージ６を手前側に測定者（オペレータ）の近傍に、被測定物１０のセット作業が行いやすいように摺動台７３を移動させるのに続いて、第２エアスライド８を動作させて、干渉光学系２を右側にサンプルステージ６から離れる方向に摺動台８３を移動させ、被測定物１０をセットする作業に干渉しないように作業スペースを広げる（ステップＳ２）。 First, after the power is turned on, an initial movement operation is performed in order to set the DUT 10. In step S1, the first air slide 7 on the left side is operated, and the slide stage 73 is moved in the vicinity of the measurer (operator) with the sample stage 6 on the near side so that the work for setting the object to be measured 10 can be easily performed. Subsequently, the second air slide 8 is operated to move the interference optical system 2 to the right side in a direction away from the sample stage 6 so as not to interfere with the work of setting the object to be measured 10. The work space is expanded (step S2).

その後、カバー９５の前扉９５ａおよび上扉９５ｂを開き、測定者が手作業によって被測定物１０を、回転ステージ部６２の先端部の被測定物ホルダー６３にセットする。具体的には、測定者が被測定物１０（非球面形状を有するレンズ等）を保管位置より取り出し、サンプルステージ６の先端における被測定物ホルダー６３に運び、被測定物１０を所定姿勢に保持させる（ステップＳ３）。そして、上記カバー９５の前扉９５ａおよび上扉９５ｂを閉じ、カバー９５の内部の雰囲気（温度および湿度）が安定するまでの所定時間が経過するのを待ってから、測定を開始する。 Thereafter, the front door 95 a and the upper door 95 b of the cover 95 are opened, and the measurer manually sets the device under test 10 to the device under test holder 63 at the tip of the rotary stage unit 62. Specifically, the measurer takes out the object to be measured 10 (a lens having an aspherical shape, etc.) from the storage position, carries it to the object holder 63 at the tip of the sample stage 6, and holds the object to be measured 10 in a predetermined posture. (Step S3). Then, the front door 95a and the upper door 95b of the cover 95 are closed, and after waiting for a predetermined time until the atmosphere (temperature and humidity) inside the cover 95 is stabilized, measurement is started.

次に測定準備を行うものであり、ステップＳ４で第１エアスライド７および第２エアスライド８を動作させて、干渉光学系２と被測定物１０の被測定面１０ａとを正対位置、つまり被測定面軸Ｓと測定光軸Ｌとが一致する正対位置に移動させる。つまり、第１エアスライド７の摺動台７３を後退動作させて測定初期位置に移動させる一方、第２エアスライド８は摺動台８３を前進移動させて干渉光学系２の照射先端部を被測定物１０に接近させるとともに、被測定面軸Ｓ（回転軸Ｅ）と干渉光学系２の測定光軸Ｌとが一直線上に一致する測定初期状態に移動させる。 Next, measurement preparation is performed. In step S4, the first air slide 7 and the second air slide 8 are operated to bring the interference optical system 2 and the measured surface 10a of the measured object 10 into a directly-facing position, that is, The measurement surface axis S and the measurement optical axis L are moved to the directly facing position where they coincide. That is, the slide base 73 of the first air slide 7 is moved backward to move to the initial measurement position, while the second air slide 8 moves the slide base 83 forward to cover the irradiation tip of the interference optical system 2. While making it approach the measurement object 10, it moves to the measurement initial state where the to-be-measured surface axis | shaft S (rotation axis E) and the measurement optical axis L of the interference optical system 2 correspond on a straight line.

なお、非球面形状測定装置１の初期設定（設置調整）において、回転ステージ部６２の中心位置と被測定物ホルダー６３の保持中心位置、つまり被測定物１０の被測定面軸Ｓが一致するように、調整部６１の手動調整により、第１エアスピンドル７０の回転軸Ｅに対し、回転ステージ部６２の中心位置（Ｘ位置およびＺ位置）、角度（θＸ，θＺ）等を設定しておく。その際、後述の光干渉測定により被測定物ホルダー６３に保持した被測定物１０の中心部の干渉光を撮像した２次元イメージセンサ４２の画像データ（干渉縞）を用いて被測定面軸Ｓを求め、上記位置調整を行うことが可能である。 In the initial setting (installation adjustment) of the aspherical surface shape measuring apparatus 1, the center position of the rotary stage unit 62 and the holding center position of the object holder 63, that is, the surface axis S of the object to be measured 10 coincide with each other. In addition, the center position (X position and Z position), angle (θX, θZ), and the like of the rotary stage 62 are set with respect to the rotation axis E of the first air spindle 70 by manual adjustment of the adjustment unit 61. At that time, the surface axis S to be measured using image data (interference fringes) of the two-dimensional image sensor 42 that captures the interference light at the center of the device under test 10 held in the device holder 63 to be measured by optical interference measurement described later. And the above-mentioned position adjustment can be performed.

さらに、ステップＳ５において第２エアスピンドル８０の回転駆動を行い、干渉光学系２の測定角度（被測定面軸Ｓと測定光軸Ｌとのなす角度）を設定角度に調整する。その際、測定角度が０度で正対位置（一直線上）の場合には、この動作は不要である。 Further, in step S5, the second air spindle 80 is rotationally driven to adjust the measurement angle of the interference optical system 2 (the angle formed by the measured surface axis S and the measurement optical axis L) to a set angle. At this time, if the measurement angle is 0 degree and the position is directly facing (on a straight line), this operation is not necessary.

次に、第１エアスピンドル７０の駆動を開始して、被測定物１０の回転を開始し、測定可能にする（ステップＳ６）とともに、光干渉測定を行う（ステップＳ７）。この測定は、光源部２０からの測定光を平面基準板２４を透過させて被測定面１０ａに照射し、反射された戻り光と、平面基準板２４の参照基準平面２４ａからの参照光との干渉により形成される干渉光の画像データつまり干渉縞（反射面の形状情報を担持している）を、１次元イメージセンサ３２および２次元イメージセンサ４２を用いて撮像し、その画像データを画像処理および形状解析により測定データを算出し、表示装置５１に表示し、データ保存する。なお、フリンジスキャン計測を行う場合は、フリンジスキャンアダプタ２８を用いて、平面基準板２４の測定光軸Ｌ方向の位置を適宜変更し、変更毎に測定を行う。 Next, driving of the first air spindle 70 is started, rotation of the DUT 10 is started to enable measurement (step S6), and optical interference measurement is performed (step S7). In this measurement, the measurement light from the light source unit 20 is transmitted through the flat reference plate 24 to irradiate the measurement target surface 10a, and the reflected return light and the reference light from the reference reference plane 24a of the flat reference plate 24 are used. Image data of interference light formed by interference, that is, interference fringes (having reflection surface shape information) is captured using the one-dimensional image sensor 32 and the two-dimensional image sensor 42, and the image data is subjected to image processing. Then, measurement data is calculated by shape analysis, displayed on the display device 51, and stored. In the case of performing fringe scan measurement, the position of the flat reference plate 24 in the measurement optical axis L direction is appropriately changed using the fringe scan adapter 28, and measurement is performed for each change.

この所定の測定角度での光干渉測定が完了すると、ステップＳ８で第１エアスピンドル７０による被測定物１０の回転を停止する一方、次の測定のために、ステップＳ９で第１エアスライド７の摺動台７３を移動させて、次の測定角度に応じたＸ方向位置に被測定物１０を移動させる。また、同時に第２エアスピンドル８０を作動させて、干渉光学系２の測定光軸Ｌを所定角度に旋回させる（ステップＳ１０）とともに、第２エアスライド８の摺動台８３を移動させて干渉光学系２のＹ方向位置を変更する。 When the optical interference measurement at the predetermined measurement angle is completed, the rotation of the object to be measured 10 by the first air spindle 70 is stopped in step S8, while the first air slide 7 is moved in step S9 for the next measurement. The slide table 73 is moved, and the DUT 10 is moved to a position in the X direction corresponding to the next measurement angle. At the same time, the second air spindle 80 is operated to rotate the measurement optical axis L of the interference optical system 2 by a predetermined angle (step S10), and the slide table 83 of the second air slide 8 is moved to cause interference optical. The Y direction position of the system 2 is changed.

たとえば、図４の正対位置から図５の直交位置まで測定角度を変更する場合には、第２エアスピンドル８０の旋回動作に応じて、干渉光学系２の照射先端部２ａがＸ方向は手前側（前進側）に、Ｙ方向は右側（後退側）に移動することに伴い、第１エアスライド７は被測定物１０をＸ方向に前進移動させる一方、第２エアスライド８は干渉光学系２を前進移動させることで、被測定物１０と干渉光学系２とが所定の距離および角度の相対姿勢となるように調整する。 For example, when the measurement angle is changed from the directly-facing position in FIG. 4 to the orthogonal position in FIG. 5, the irradiation tip 2 a of the interference optical system 2 is in front of the X direction according to the turning operation of the second air spindle 80. As the Y direction moves to the right side (forward side) and to the right side (backward side), the first air slide 7 moves the object to be measured 10 forward in the X direction, while the second air slide 8 moves to the interference optical system. By moving 2 forward, the object to be measured 10 and the interference optical system 2 are adjusted so as to have a relative attitude of a predetermined distance and angle.

上記のように測定角度を変更した後、ステップＳ６に戻って第１エアスピンドル７０の回転動作を開始して被測定物１０を被測定面軸Ｓの回りに回転させつつ、変更された測定角度における光干渉測定をステップＳ７で同様に行う。 After changing the measurement angle as described above, the measurement angle is changed while returning to step S6 and starting the rotation operation of the first air spindle 70 to rotate the DUT 10 about the measurement surface axis S. In step S7, the optical interference measurement is performed in the same manner.

これらの測定動作を１つの被測定物１０で測定が必要な角度分の回数だけ順次繰り返した後、つまり、被測定物１０の非球面形状に対応して設定された所定角度毎における測定が終了した際には、ステップＳ１２に移行して被測定物１０を初期位置に戻すものであり、第１エアスライド７および第２エアスライド８を作動して、上記ステップＳ３の被測定物１０をセットしたときと同じ位置に移動させ、ステップＳ１３で測定後の被測定物１０を被測定物ホルダー６３から取り外して、次の未測定の被測定物１０をセットした後、上記ステップＳ４に戻り、以下、上記と同様に新たにセットした被測定物１０に対応した測定角度の設定を行う。 These measurement operations are sequentially repeated as many times as necessary for one object 10 to be measured, that is, the measurement for each predetermined angle set corresponding to the aspherical shape of the object 10 is completed. In this case, the process proceeds to step S12 to return the object to be measured 10 to the initial position. The first air slide 7 and the second air slide 8 are actuated to set the object 10 to be measured in step S3. The measured object 10 after measurement is removed from the measured object holder 63 in step S13, the next unmeasured object 10 is set, and the process returns to step S4. In the same manner as described above, the measurement angle corresponding to the newly set object 10 is set.

上記測定動作を被測定物１０の数だけ繰り返し、すべての測定が終了した際には、ステップＳ１３で最終の被測定物１０を被測定物ホルダー６３から取り外し、電源をオフにして停止するものである。 When the above measurement operation is repeated for the number of objects to be measured 10 and all measurements are completed, the final object to be measured 10 is removed from the object holder 63 in step S13, and the power is turned off to stop. is there.

上記のように順次測定角度を変更して光干渉測定された画像データは、それぞれが担持している輪帯状領域形状情報を解析制御装置５０において解析処理し、被測定面１０ａ全域の形状情報を求める。 As described above, the image data obtained by sequentially changing the measurement angle and performing the optical interference measurement is subjected to analysis processing on the annular zone shape information carried by the analysis control device 50, and the shape information of the entire surface to be measured 10a is obtained. Ask.

以上、本発明の実施形態について詳細に説明したが、本発明は上述の実施形態に限定されるものではなく、種々に態様を変更することが可能である。 As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the above-mentioned embodiment, A various aspect can be changed.

例えば、上述の実施形態では、低強度部６４を切欠き構造に形成して断面積を低減することで曲げ強度が低くなるように構成し、干渉光学系２の照射先端部２ａとの衝突時の衝撃を吸収するように構成しているが、その強度低下構造としては、断面積低減構造のほか、低強度材料を使用することなどの変形が可能である。ただし、測定精度確保の点からは、被測定物１０の保持精度を確保する必要があり、可撓性または柔軟性を有する材料で形成することは不適切である。 For example, in the above-described embodiment, the low-strength portion 64 is formed in a notch structure so that the bending area is reduced by reducing the cross-sectional area, and at the time of collision with the irradiation tip portion 2a of the interference optical system 2 However, the strength reduction structure can be modified such as using a low-strength material in addition to the cross-sectional area reduction structure. However, from the viewpoint of ensuring measurement accuracy, it is necessary to ensure the holding accuracy of the DUT 10, and it is inappropriate to form the material with flexibility or flexibility.

また、上述の実施形態では、第１エアスライド７をＸ方向に設置し、第２エアスライド８をＹ方向に設置しているが、逆に第１エアスライド７をＹ方向に設置し、第２エアスライド８をＸ方向に設置するようにしてもよい。 In the above-described embodiment, the first air slide 7 is installed in the X direction and the second air slide 8 is installed in the Y direction. Conversely, the first air slide 7 is installed in the Y direction. The two air slides 8 may be installed in the X direction.

また、上述の実施形態では、昇降アクチュエータ８７を干渉光学機構Ｂに設置しているが、被測定物保持機構Ａとの少なくとも一方に備えているように構成すればよい。 In the above-described embodiment, the elevating actuator 87 is installed in the interference optical mechanism B. However, it may be configured to be provided in at least one of the measured object holding mechanism A.

また、上述の実施形態では、被測定面１０ａが凹面部および凸面部を有する形状のものとされているが、このような形状の被測定面に測定対象が限定されるものではない。本発明の非球面形状測定装置は、回転対称な種々の非球面形状の被測定面の測定に用いることが可能である。 Moreover, in the above-mentioned embodiment, although the to-be-measured surface 10a is made into the shape which has a concave surface part and a convex surface part, a measuring object is not limited to the to-be-measured surface of such a shape. The aspherical shape measuring apparatus of the present invention can be used for measuring various measurement surfaces having various aspherical shapes that are rotationally symmetric.

１非球面形状測定装置
２干渉光学系
２ａ照射先端部
３第１撮像系
４第２撮像系
５測定解析系
６サンプルステージ
７第１エアスライド（第１スライド機構）
８第２エアスライド（第２スライド機構）
９定盤
１０被測定物
１０ａ被測定面
２０光源部
２１ビーム径拡大レンズ
２２光束分岐光学素子
２３コリメータレンズ
２４平面基準板
２４ａ参照基準平面
２５鏡筒
２８フリンジスキャンアダプタ
２９ピエゾ素子
３０結像レンズ
３１撮像カメラ
３２１次元イメージセンサ
３４光束分岐光学素子
３５鏡筒
４０結像レンズ
４１撮像カメラ
４２２次元イメージセンサ
４５鏡筒
５０解析制御装置
５１表示装置
５２入力装置
６０基台部
６１調整部
６２回転ステージ部
６３被測定物ホルダー
６４低強度部
７０第１エアスピンドル（被測定物回転機構）
７３摺動台
７４ガイド
８０第２エアスピンドル（光学系旋回機構）
８１保持部
８２基台部
８３摺動台
８４ガイド
８６エアブッシュ
８７昇降アクチュエータ（昇降機構）
９１支持脚
９２防振台
９５カバー
９５ａ前扉
９５ｂ上扉
Ａ被測定物保持機構
Ｂ干渉光学機構
Ｅ回転軸
Ｌ測定光軸
Ｓ被測定面軸
DESCRIPTION OF SYMBOLS 1 Aspherical surface shape measuring apparatus 2 Interference optical system 2a Irradiation front-end | tip part 3 1st imaging system 4 2nd imaging system 5 Measurement analysis system 6 Sample stage 7 1st air slide (1st slide mechanism)
8 Second air slide (second slide mechanism)
DESCRIPTION OF SYMBOLS 9 Surface plate 10 Measured object 10a Measured surface 20 Light source part 21 Beam diameter expansion lens 22 Beam splitting optical element 23 Collimator lens 24 Plane reference plate 24a Reference reference plane 25 Lens barrel 28 Fringe scan adapter 29 Piezo element 30 Imaging lens 31 Imaging camera 32 One-dimensional image sensor 34 Beam splitting optical element 35 Lens barrel 40 Imaging lens 41 Imaging camera 42 Two-dimensional image sensor 45 Lens barrel 50 Analysis control device 51 Display device 52 Input device 60 Base unit 61 Adjustment unit 62 Rotation stage Part 63 Device holder 64 Low strength part 70 First air spindle (Measuring object rotating mechanism)
73 Slide base 74 Guide 80 Second air spindle (optical system turning mechanism)
81 Holding portion 82 Base portion 83 Slide table 84 Guide 86 Air bush 87 Lifting actuator (lifting mechanism)
91 Support leg 92 Anti-vibration table 95 Cover 95a Front door 95b Upper door A Measuring object holding mechanism B Interference optical mechanism E Rotating axis L Measuring optical axis S Measuring surface axis

Claims

非球面形状の被測定面を有する被測定物を保持する被測定物保持機構と、前記被測定物の被測定面に測定光を照射し該被測定面からの戻り光と参照光との干渉による干渉縞を取得する光干渉測定を行う干渉光学系を有する干渉光学機構とを備え、前記干渉縞に基づき前記被測定面の形状を測定する非球面形状測定装置であって、
前記被測定物保持機構および前記干渉光学機構は、それぞれ相対的に移動可能に設置されてなり、
前記被測定物保持機構は、前記被測定物を先端に保持するサンプルステージを備え、該サンプルステージに前記干渉光学系の照射先端部と衝突した際に衝撃を吸収する低強度部が設けられたことを特徴とする非球面形状測定装置。 An object holding mechanism for holding an object to be measured having an aspherical surface to be measured, and interference between a return light from the surface to be measured and a reference light by irradiating the surface to be measured of the object to be measured An interference optical mechanism having an interference optical system for performing an optical interference measurement for obtaining an interference fringe, and an aspherical shape measuring apparatus for measuring the shape of the surface to be measured based on the interference fringe,
The measured object holding mechanism and the interference optical mechanism are installed to be relatively movable,
The object holding mechanism includes a sample stage that holds the object to be measured at the tip, and the sample stage is provided with a low-strength portion that absorbs an impact when the sample stage collides with the irradiation tip of the interference optical system. An aspherical shape measuring apparatus characterized by the above.

前記低強度部を、切欠き構造で構成したことを特徴とする請求項１記載の非球面形状測定装置。 The aspherical shape measuring apparatus according to claim 1, wherein the low-strength portion has a notch structure.

前記サンプルステージは、前記被測定物とともに該被測定物の被測定面軸の回りに回転可能である回転ステージ部と、該回転ステージ部を回転中心位置が変更可能に保持する調整部とを備え、前記回転ステージ部が被測定物回転機構により回転駆動されるように構成してなり、前記回転ステージ部に前記低強度部を設置することを特徴とする請求項１または２記載の非球面形状測定装置。 The sample stage includes a rotation stage unit that can rotate around the measurement surface axis of the object to be measured together with the object to be measured, and an adjustment unit that holds the rotation stage unit so that the rotation center position can be changed. 3. The aspherical shape according to claim 1, wherein the rotary stage portion is configured to be rotationally driven by a measured object rotating mechanism, and the low-strength portion is installed on the rotary stage portion. measuring device.

前記被測定物保持機構は、前記被測定物を被測定面軸を中心として回転させる被測定物回転機構と、該被測定物回転機構を搭載し前記被測定面軸と直交方向または平行方向に直線移動させる第１スライド機構とを備え、
前記干渉光学機構は、前記干渉光学系を保持し該干渉光学系をその測定光軸と前記被測定面軸とのなす測定角度を変更可能に旋回させる光学系旋回機構と、該光学系旋回機構を搭載し前記第１スライド機構の移動方向と直交方向に直線移動させる第２スライド機構とを備えることを特徴とする請求項１〜３のうちいずれか１項記載の非球面形状測定装置。 The measurement object holding mechanism includes a measurement object rotation mechanism that rotates the measurement object about a measurement surface axis, and a measurement object rotation mechanism that is mounted in a direction orthogonal or parallel to the measurement surface axis. A first slide mechanism for linear movement,
The interference optical mechanism holds the interference optical system and rotates the interference optical system so that the measurement angle between the measurement optical axis and the axis of the surface to be measured can be changed, and the optical system rotation mechanism The aspherical shape measuring apparatus according to any one of claims 1 to 3, further comprising: a second slide mechanism that is mounted and moves linearly in a direction orthogonal to the moving direction of the first slide mechanism.

前記第１スライド機構および前記第２スライド機構をエアスライドで構成してなることを特徴とする請求項４記載の非球面形状測定装置。 The aspherical shape measuring apparatus according to claim 4, wherein the first slide mechanism and the second slide mechanism are constituted by air slides.

前記被測定物回転機構および前記光学系旋回機構をエアスピンドルで構成してなることを特徴とする請求項４記載の非球面形状測定装置。
The aspherical shape measuring apparatus according to claim 4, wherein the object rotation mechanism and the optical system turning mechanism are constituted by an air spindle.