JP2003279330A - Shape measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for acquiring a focus position of a shape measuring apparatus having two or more optical displacement meters. <P>SOLUTION: The shape measuring apparatus having two or more optical displacement meters comprises a means for acquiring a photodetecting quantity of all optical displacement meters, a means for calculating the sum of the photodetecting quantity, a means for storing the maximum photodetecting quantity sum Fmax and an optical displacement meter position L for acquiring the sum Fmax, and a means for scanning the displacement in an optical axis direction. When a focus position is decided, the meters are scanned so as to gradually approach to an object to be measured from a remote point by the scanning means, the sum F of the photodetecting quantities F1, F2,..., Fn of the meters during scanning is calculated by an arithmetic means, the present sum Fis always compared with the stored sum Fmax, a spot in which the sum F becomes maximum is searched, and is set to a focus spot Lf. <P>COPYRIGHT: (C)2004,JPO

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、形状測定装置に関
する。より詳しくは、２つ以上の光学式変位計を有する
形状測定装置のフォーカス位置取得方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring device. More specifically, the present invention relates to a focus position acquisition method for a shape measuring device having two or more optical displacement gauges.

【０００２】[0002]

【従来の技術】従来、非球面レンズ等の形状測定方法と
しては、接触式形状測定装置により測定することが一般
的であるが、接触式の測定方法によると、被測定物にキ
ズがつくという問題があった。そのため、被測定物の表
面の損傷が問題となるような測定の場合には非接触プロ
ーブを用いた測定が用いられるようになってきている。
この方法は、光学式変位計を常に被測定物表面にフォー
カス追従制御させながら被測定面を走査し、光学式変位
計の移動量から面形状を測定するものである。2. Description of the Related Art Conventionally, as a shape measuring method for an aspherical lens or the like, a contact type shape measuring apparatus has been generally used. However, according to the contact type measuring method, an object to be measured is scratched. There was a problem. Therefore, in the case of measurement in which damage to the surface of the object to be measured poses a problem, measurement using a non-contact probe has come to be used.
This method scans the surface to be measured while controlling the optical displacement meter to focus and follow the surface of the object to be measured, and measures the surface shape from the amount of movement of the optical displacement meter.

【０００３】ここで、ある一つの固定された周波数のレ
ーザー光を光源としたヘテロダイン干渉計を光学式変位
計として備えた形状計測装置で、段差を含む被測定物を
測定することを考えてみる。ヘテロダイン干渉計のよう
な光学式変位計を有する形状計測装置により、段差を含
む被測定物表面を走査すると、被測定物表面の段差など
で光が途切れ、段差を越えた後において、段差の前と違
う位置でフォーカス制御をおこなってしまい、段差の後
の測定データに光学式変位計の測定範囲整数個分オフセ
ットがのることがある。これは、ヘテロダイン干渉計な
どを利用した光学式変位計の測長範囲は、高々１μｍ弱
であり、図２に示す様に同じ変位を繰り返し出力してい
るためである。Now, let us consider measuring an object to be measured including a step with a shape measuring apparatus equipped with a heterodyne interferometer using a laser light of a fixed frequency as a light source as an optical displacement meter. . When the surface of a DUT including a step is scanned by a shape measuring device having an optical displacement meter such as a heterodyne interferometer, the light is interrupted by the step on the surface of the DUT, and after the step, before the step. The focus control may be performed at a different position, and the measurement data after the step may be offset by an integral number of the measurement range of the optical displacement meter. This is because the measuring range of the optical displacement meter using the heterodyne interferometer is at most a little less than 1 μm and the same displacement is repeatedly output as shown in FIG.

【０００４】つまり、段差の高さが光学式変位計の測定
範囲を越えると、段差前と段差後では、被測定物と光学
式変位計の距離は、本当は測定範囲整数個分だけ異なる
（図２、図３の距離Ａ、Ｂ）のに、光学式変位計の出力
においては、同じ出力となり（図２の出力Ａ、Ｂ）、こ
の出力に基づいてフォーカス制御を行うため、段差の前
後で形状データにオフセットがのってしまうのである。
段差などを測定するには、その高さよりも光学式変位計
の測定範囲が充分広ければ、上述のことが発生しない。That is, when the height of the step exceeds the measurement range of the optical displacement meter, the distance between the object to be measured and the optical displacement meter before and after the step actually differs by an integral number of measurement ranges (Fig. 2 and the distances A and B in FIG. 3), the output of the optical displacement meter is the same (outputs A and B in FIG. 2), and focus control is performed based on this output, so that before and after the step. The offset is added to the shape data.
To measure a step or the like, the above does not occur if the measurement range of the optical displacement meter is sufficiently wider than the height.

【０００５】ヘテロダイン干渉計の測定範囲を広げるた
めには、複数のわずかに周波数のずれたレーザー光を光
源とすると有効であることが知られている（特開平１１
−２０１７２７）。そこで、被測定物に段差があるよう
な被測定物を精度よく測定するためには、わずかにずれ
た複数の周波数のレーザ光を光源としたヘテロダイン干
渉計を光学式変位計として備えた形状計測装置が用いら
れる。これは、同一地点を測定可能な複数の光学式変位
計を備えた形状計測装置とみなすこともできる。In order to extend the measurement range of the heterodyne interferometer, it has been known that it is effective to use a plurality of laser beams having slightly shifted frequencies as light sources (Japanese Patent Laid-Open No. 11-1999).
-2017727). Therefore, in order to accurately measure an object to be measured that has a step, the shape measurement equipped with a heterodyne interferometer that uses laser light of multiple frequencies that are slightly shifted as a light source is an optical displacement meter. The device is used. This can also be regarded as a shape measuring device provided with a plurality of optical displacement meters capable of measuring the same point.

【０００６】上述のような光学式変位計を、一つあるい
は２つ以上備えた形状計測装置において、測定を行うに
は、まずフォーカス位置を取得しなければならない。特
開平５−３４１１９号公報、特開平５−１０７０５７号
公報等に１つの光学式変位計を有する形状計測装置のフ
ォーカス位置取得方法が記されている。すなわち、測定
を始める前に光学式変位計の光軸方向に、光学式変位計
を走査して、徐々に光学式変位計と被測定物の距離を近
づけるといった工程を行い、走査中の光学式変位計が受
ける受光量を監視し、受光量が最大になった地点を最も
測定光が集光した地点とし、当該地点をフォーカス位置
と決定している。In order to perform the measurement in the shape measuring apparatus equipped with one or two or more optical displacement meters as described above, it is necessary to first obtain the focus position. JP-A-5-34119, JP-A-5-107057 and the like describe a focus position acquisition method for a shape measuring device having one optical displacement gauge. That is, before starting the measurement, the optical displacement meter is scanned in the optical axis direction of the optical displacement meter to gradually bring the distance between the optical displacement meter and the measured object closer to each other. The amount of light received by the displacement meter is monitored, and the point where the amount of received light is maximum is determined as the point where the measurement light is most condensed, and the point is determined as the focus position.

【０００７】[0007]

【発明が解決しようとする課題】しかし、前述した同一
地点を測定する２つ以上の光学式変位計を非接触プロー
ブとして備え、フォーカス位置を取得する必要がある形
状計測装置においては、特開平５−３４１１９号公報、
特開平５−１０７０５７号公報等に記された方法では、
フォーカス位置を取得することができない。それは、２
つ以上の光学式変位計を有する形状計測装置において
は、組立て上の誤差などにより、それぞれの光学変位計
が受ける受光量が最大になる地点が、それぞれの光学変
位計において微妙に異なる地点となり、上記のような方
法ではフォーカス位置を決定できないという問題があ
る。However, in the shape measuring device which is provided with two or more optical displacement gauges for measuring the same point as the non-contact probe and it is necessary to acquire the focus position, Japanese Patent Laid-Open Publication No. Hei 5 (1999) -58200 has been proposed. -34119 gazette,
In the method described in JP-A-5-107057, etc.,
Unable to get the focus position. It is 2
In a shape measuring device having two or more optical displacement gauges, the point where the amount of light received by each optical displacement gauge becomes maximum due to assembly errors, etc., becomes a slightly different point in each optical displacement gauge, The above method has a problem that the focus position cannot be determined.

【０００８】本発明は、上記の問題を鑑み、２つ以上の
光学式変位計を有する形状計測装置においても、光学変
位計のフォーカス地点を決定する方法を提供することを
目的としてなされたものである。In view of the above problems, the present invention has been made for the purpose of providing a method for determining a focus point of an optical displacement meter even in a shape measuring apparatus having two or more optical displacement meters. is there.

【０００９】[0009]

【課題を解決するための手段】請求項１の発明は、同じ
測定点を測定する２つ以上の光学式変位計を非接触プロ
ーブとして備え、測定を行う前に光学式変位計の測定光
が集光するフォーカス地点を取得する必要がある形状測
定装置において、それぞれの光学式変位計の受光量Ｆ
１,Ｆ２、・・・・,Ｆｎを取得する手段と、光学式変位
計を光軸方向に走査させる制御手段と、光学式変位計の
移動量を測定する手段と、前記受光量和Ｆを演算する手
段と前記受光量和Ｆを記憶する手段を有し、前記受光量
和Ｆの演算結果に基づいてフォーカス地点を決定するこ
とを特徴とし、もって２つ以上の光学式変位計を有する
形状測定装置においてもフォーカス地点を決定すること
を可能としたものである。According to a first aspect of the present invention, two or more optical displacement gauges for measuring the same measurement point are provided as non-contact probes, and the measurement light of the optical displacement gauge is measured before the measurement. In the shape measuring device that needs to obtain the focus point for focusing, the amount of received light F of each optical displacement meter
, Fn, a control means for scanning the optical displacement meter in the optical axis direction, a means for measuring the movement amount of the optical displacement meter, and the received light amount sum F. A shape having a means for calculating and a means for storing the sum F of received light amount, and determining a focus point based on a calculation result of the sum F of received light amount. The measuring device can also determine the focus point.

【００１０】請求項２の発明は、請求項１記載の形状測
定装置において、フォーカス地点を決定する方法とし
て、光学式変位計を走査手段により被測定物の遠点に
移動させる、徐々に光学式変位計を被測定物に近づけ
る方向に走査させる。同時に光学式変位計の受光量Ｆ
１、Ｆ２・・・、Ｆｎと移動量Ｌを取得し、演算手段
により受光量和Ｆ（＝Ｆ１＋Ｆ２＋Ｆ３＋・・・・Ｆ
ｎ）を演算し、記憶手段により記憶している最大受光
量和Ｆｍａｘと比較し、記憶されているＦｍａｘより
現在の受光量和Ｆが大きかった場合、最大受光量和Ｆｍ
ａｘとして現在の受光量和Ｆ、最大受光量時移動量Ｌｆ
として現在の光学式変位計の移動量Ｌを記憶する。受
光量和Ｆが最大受光量和Ｆｍａｘ×α以下で、かつ、Ｆ
ｍａｘがβ以上の場合走査を停止する、という工程を含
むことを特徴とし、もって、フォーカス地点を速やか
に、かつ、確実に発見できることを可能としたものであ
る。According to a second aspect of the present invention, in the shape measuring apparatus according to the first aspect, as a method of determining a focus point, an optical displacement meter is moved to a far point of the object to be measured by a scanning means, and the optical type is gradually changed. The displacement meter is scanned in the direction of approaching the object to be measured. At the same time, the amount of light received by the optical displacement meter F
, Fn, and the moving amount L are acquired, and the light receiving amount sum F (= F1 + F2 + F3 + ... F
n) is calculated and compared with the maximum received light amount sum Fmax stored by the storage means. If the current received light amount sum F is larger than the stored Fmax, the maximum received light amount sum Fm.
The sum F of the current received light amount as ax and the movement amount Lf at the time of maximum received light amount
The current movement amount L of the optical displacement meter is stored as. The total received light amount F is less than or equal to the maximum total received light amount Fmax × α, and F
The present invention is characterized by including a step of stopping the scanning when max is β or more, which enables the focus point to be found promptly and surely.

【００１１】請求項３の発明は、請求項２記載の形状測
定装置において、αを０＜α＜１とすることを特徴と
し、もって、光学式変位計がフォーカス地点を通過した
ことを推測することを可能としたものである。According to a third aspect of the present invention, in the shape measuring apparatus according to the second aspect, α is set to 0 <α <1. Therefore, it is estimated that the optical displacement meter has passed the focus point. It made it possible.

【００１２】請求項４の発明は、請求項２記載の形状測
定装置において、βを０＜β＜Ｆｍａｘとすることを特
徴とし、もって、フォーカス地点を過ぎる前に走査を停
止しないようにしたものである。According to a fourth aspect of the present invention, in the shape measuring apparatus according to the second aspect, β is set to 0 <β <Fmax, so that the scanning is not stopped before passing the focus point. Is.

【００１３】請求項５の発明は、請求項２記載の形状測
定装置において、走査終了後記憶手段により記憶されて
いるＬｆをフォーカス地点とすることを特徴とし、もっ
て、それぞれの受光量情報からフォーカス地点を簡易に
決定可能としたものである。According to a fifth aspect of the present invention, in the shape measuring apparatus according to the second aspect, Lf stored by the storage means after scanning is set as a focus point. The point can be easily determined.

【００１４】[0014]

【発明の実施の形態】図１は、本発明の一実施例を説明
するための概略構成図（図１（Ａ）は平面図、図１
（Ｂ）は側面図）で、図中、１は被測定物、２は第一の
光学式変位計、３は第二の光学式変位計、４は第一の光
学式変位計受光量測定手段、５は第二の光学式変位計受
光量測定手段、６、７、８は走査手段、９は６の光学式
変位計２および３の光軸方向移動量測定手段、１０は被
測定物治具、１１は、記憶手段および制御手段である。1 is a schematic configuration diagram for explaining an embodiment of the present invention (FIG. 1 (A) is a plan view, FIG.
(B) is a side view, in which 1 is an object to be measured, 2 is a first optical displacement meter, 3 is a second optical displacement meter, and 4 is a first optical displacement meter received light amount measurement. Means 5 is a second optical displacement meter received light quantity measuring means, 6, 7 and 8 are scanning means, 9 is an optical displacement direction measuring means 6 of the optical displacement gauges 2 and 3 of 6, and 10 is a measured object. The jig 11 is a storage means and a control means.

【００１５】ここでは、形状測定装置が光学変位計を２
つ有し、駆動軸としてＸ、Ｙ、Ｚ軸の３軸（６、７、
８）有しているとしている。被測定物１と第一光学式変
位計２および第二光学式変位計３は水平に配置されてい
る。従って、Ｙ軸方向がフォーカス方向（光軸方向）で
あり、Ｘ、或いは、Ｚ方向に走査する。他に、被測定物
１と第一光学式変位計２および第二光学式変位計３を垂
直（上下）に配置し、Ｚ方向をフォーカス方向とし、
Ｘ、Ｙ方向に走査して構わない、なお、１０は被測定物
取り付け治具である。In this case, the shape measuring device uses an optical displacement gauge.
Has three driving axes, namely X, Y, and Z axes (6, 7,
8) I have it. The DUT 1, the first optical displacement meter 2 and the second optical displacement meter 3 are horizontally arranged. Therefore, the Y-axis direction is the focus direction (optical axis direction), and scanning is performed in the X or Z direction. In addition, the DUT 1, the first optical displacement meter 2 and the second optical displacement meter 3 are arranged vertically (up and down), and the Z direction is the focus direction,
It does not matter if scanning is performed in the X and Y directions, and 10 is an object mounting jig.

【００１６】図４、図５により、本発明を説明する。The present invention will be described with reference to FIGS.

【００１７】光学式変位計を有する走査型形状測定装置
においては、測定を始める前に、フォーカス引き込み動
作を行わせ、フォーカス位置を取得しなければ測定を行
うことができない。光学式変位計を一つだけを有する形
状測定装置の場合には、光学式変位計をフォーカス位置
近傍で光軸方向に走査して光学式変位計の受光量が最大
となる地点をフォーカス位置として、フォーカス位置を
取得している。In the scanning type profile measuring apparatus having the optical displacement gauge, the measurement cannot be performed unless the focus pull-in operation is performed and the focus position is acquired before starting the measurement. In the case of a shape measuring device that has only one optical displacement gauge, the optical displacement gauge is scanned in the optical axis direction in the vicinity of the focus position and the point where the amount of light received by the optical displacement gauge is maximum is set as the focus position. , The focus position is acquired.

【００１８】しかし、２つ以上の光学式変位計を有する
形状測定装置では、それぞれの光学式変位計のフォーカ
ス地点が微妙に異なるため、上記の方法では、最適なフ
ォーカス位置を得ることができない。２つ以上の光学式
変位計を有する形状測定装置における、光学式変位計の
受光量と位置の関係を図４に示す。光学変位計を遠点か
らフォーカス地点方向へ移動させていくと、徐々に受光
量が増え始め（図４．Ａ）、フォーカス地点で最大とな
り（図４．Ｂ）、フォーカス地点を通過すると、再び受
光量は少なくなる（図４．Ｃ）。本発明では、それぞれ
の受光量の和が最大となった地点をフォーカス地点（図
４．Ｂ）とすることにする。However, in a shape measuring device having two or more optical displacement gauges, the focus points of the respective optical displacement gauges are slightly different, so that the above method cannot obtain an optimum focus position. FIG. 4 shows the relationship between the amount of light received and the position of the optical displacement meter in the shape measuring device having two or more optical displacement meters. When the optical displacement sensor is moved from the far point toward the focus point, the amount of received light gradually increases (Fig. 4.A) and reaches the maximum at the focus point (Fig. 4.B). The amount of light received decreases (Fig. 4.C). In the present invention, the point at which the sum of the received light amounts is maximum is the focus point (FIG. 4.B).

【００１９】具体的なフォーカス位置の取得方法は以下
の工程の通りである。A specific focus position acquisition method is as follows.

【００２０】まず、光学式変位計２および光学式変位計
３を走査手段６により、被測定物の遠点に移動させる
（Ｓ２）。次に、走査手段６により、被測定物１と光学
式変位計２および光学式変位計３を徐々に近づける方向
へ移動させる（Ｓ３）。同時に、光学式変位計２および
光学式変位計３の受光量Ｆ１、Ｆ２を受光取得手段４お
よび受光取得手段５から取得し、受光量和Ｆを演算手段
１１により算出する（Ｓ４）。算出した受光量和Ｆを、
記憶手段により記憶している最大受光量和Ｆｍａｘと比
較し（Ｓ５）、現在の受光量和Ｆが保持している最大受
光量和Ｆｍａｘより大きければ、現在の受光量和Ｆを最
大受光量和Ｆｍａｘとして記憶手段により記憶保持す
る。また、その時のＹ軸移動量Ｌも、最大受光量和が得
られた位置Ｌｆとして、記憶手段により記憶保持する
（Ｓ６）。First, the optical displacement meter 2 and the optical displacement meter 3 are moved to the far point of the object to be measured by the scanning means 6 (S2). Next, the scanning means 6 moves the DUT 1, the optical displacement meter 2, and the optical displacement meter 3 in a direction in which they gradually approach each other (S3). At the same time, the light receiving amounts F1 and F2 of the optical displacement meter 2 and the optical displacement meter 3 are acquired from the light receiving acquiring means 4 and the light receiving acquiring means 5, and the light receiving amount sum F is calculated by the calculating means 11 (S4). The calculated received light amount sum F is
It is compared with the maximum received light amount sum Fmax stored by the storage means (S5), and if the current received light amount sum F is larger than the held maximum received light amount sum Fmax, the current received light amount sum F is summed to the maximum received light amount sum. The storage means stores and holds it as Fmax. The Y-axis movement amount L at that time is also stored and held by the storage means as the position Lf at which the maximum sum of received light amounts is obtained (S6).

【００２１】さらに、最大受光量和Ｆｍａｘと現在の受
光量和Ｆとの比較を行い、Ｆｍａｘ×αよりもＦが小さ
く、かつ、Ｆｍａｘが在る閾値βよりも大きければフォ
ーカス地点をもはや通過したとして、走査を停止させる
（Ｓ７、Ｓ８）。フォーカス位置取得工程は、これで終
了する。このときに記憶している移動量Ｌｆが最大受光
量和取得位置であり、すなわち、フォーカス位置であ
る。上記の走査停止条件を満たさない場合は、図５のフ
ロー図のＳ３から、走査終了条件を満たすまで繰り返し
行う。Further, the maximum received light amount sum Fmax is compared with the current received light amount sum F, and if F is smaller than Fmax × α and larger than the threshold β where Fmax exists, the focus point is no longer passed. As a result, the scanning is stopped (S7, S8). This is the end of the focus position acquisition process. The movement amount Lf stored at this time is the maximum light reception amount sum acquisition position, that is, the focus position. If the above scanning stop condition is not satisfied, the process is repeated from S3 in the flowchart of FIG. 5 until the scanning end condition is satisfied.

【００２２】ここで、αは、０＜α＜１とする。通常
は、０．５〜０．６で使用する。すなわち、現在の受光
量和Ｆが最大受光量和Ｆｍａｘに対して半分程度となっ
たら、光学式変位計がフォーカス地点を通過したものと
判断し、走査終了条件としている。しかし、フォーカス
位置を通過する前の受光量は非常に小さく値も不安定な
ため、フォーカス地点を通過する前に走査が終了してし
まう恐れがある。それゆえ、Ｆｍａｘに閾値を設け、Ｆ
ｍａｘがある値以上の場合にしか、上記の機能を働かせ
ないようにしている。すなわち、「Ｆ＜（Ｆｍａｘ×
α）」と「Ｆｍａｘ＞β」両方を満たす事を光学式変位
計２および３の走査終了条件としている。βは通常、Ｆ
ｍａｘ×０．１もしくは×０．２程度が適当である。Here, α is set to 0 <α <1. Usually, 0.5 to 0.6 is used. That is, when the current light receiving amount sum F becomes about half of the maximum light receiving amount sum Fmax, it is determined that the optical displacement meter has passed the focus point, and the scanning end condition is set. However, since the amount of received light before passing through the focus position is very small and the value is unstable, there is a risk that scanning will end before passing through the focus point. Therefore, a threshold is set for Fmax, and Fmax
Only when max is a certain value or more, the above function is made to work. That is, “F <(Fmax ×
It is a scanning end condition of the optical displacement meters 2 and 3 that both α) ”and“ Fmax> β ”are satisfied. β is usually F
A value of max × 0.1 or × 0.2 is suitable.

【００２３】上記の方法により、フォーカス位置を決定
した後は、フォーカス位置まで光学変位計を移動させフ
ォーカス制御に切り替え、Ｘ軸、Ｚ軸を走査させて被測
定物の形状測定を行う。After the focus position is determined by the above method, the optical displacement meter is moved to the focus position to switch to focus control, and the X and Z axes are scanned to measure the shape of the object to be measured.

【００２４】[0024]

【発明の効果】請求項１の発明によれば、同じ測定点を
測定する２つ以上の光学式変位計を非接触プローブとし
て備え、測定を行う前に光学式変位計の測定光が集光す
るフォーカス地点を取得する必要がある形状測定装置に
おいて、それぞれの光学式変位計の受光量Ｆ１,Ｆ２,・
・・・,Ｆｎを取得する手段と、光学式変位計を光軸方
向に走査させる制御手段と、光学式変位計の移動量を測
定する手段と、前記受光量和Ｆを演算する手段と前記受
光量和Ｆを記憶する手段を有し、前記受光量和Ｆの演算
結果に基づいてフォーカス地点を決定することを特徴と
し、２つ以上の光学式変位計の受光量和Ｆを利用してい
るので、２つ以上の光学式変位計を有する形状測定装置
においてもフォーカス地点を決定することを可能とな
る。According to the first aspect of the present invention, two or more optical displacement gauges for measuring the same measurement point are provided as non-contact probes, and the measurement light of the optical displacement gauge is condensed before the measurement. In the shape measuring device that needs to acquire the focus point to be received, the amount of light received F1, F2 ,.
..., Fn acquisition means, control means for scanning the optical displacement meter in the optical axis direction, means for measuring the movement amount of the optical displacement meter, means for calculating the received light amount sum F, and It is characterized by having a means for storing the sum F of received light and determining the focus point based on the calculation result of the sum F of received light, using the sum F of received light of two or more optical displacement meters. Therefore, the focus point can be determined even in the shape measuring device having two or more optical displacement gauges.

【００２５】請求項２の発明によれば、請求項１記載の
形状測定装置において、フォーカス地点を決定する方法
として、光学式変位計を走査手段により被測定物の遠
点に移動させる、徐々に光学式変位計を被測定物に近
づける方向に走査させる。同時に光学式変位計の受光
量Ｆ１、Ｆ２・・・、Ｆｎと移動量Ｌを取得し、演算
手段により受光量和Ｆ（＝Ｆ１＋Ｆ２＋Ｆ３＋・・・・
Ｆｎ）を演算し、記憶手段により記憶している最大受
光量和Ｆｍａｘと比較し、記憶されているＦｍａｘよ
り現在の受光量和Ｆが大きかった場合、最大受光量和Ｆ
ｍａｘとして現在の受光量和Ｆ、最大受光量時移動量Ｌ
ｆとして現在の光学式変位計の移動量Ｌを記憶する。
受光量和Ｆが最大受光量和Ｆｍａｘ×α以下で、かつ、
Ｆｍａｘがβ以上の場合走査を停止する、という工程を
含むことを特徴とし、遠点から光学式変位計を被測定物
の方へ近づけてゆき、フォーカス地点を通過した後に、
走査を止めているので、フォーカス地点を確実かつ速や
かに発見可能となる。According to a second aspect of the present invention, in the shape measuring apparatus according to the first aspect, as a method of determining the focus point, the optical displacement gauge is moved to the far point of the object to be measured by the scanning means, and gradually. The optical displacement meter is scanned in the direction of approaching the object to be measured. At the same time, the received light amounts F1, F2, ..., Fn and the movement amount L of the optical displacement meter are acquired, and the sum of received light F (= F1 + F2 + F3 + ...
Fn) is calculated and compared with the maximum received light amount sum Fmax stored by the storage means. When the current received light amount sum F is larger than the stored Fmax, the maximum received light amount sum F
The sum F of the current received light amount as max, and the movement amount L at the maximum received light amount
The current movement amount L of the optical displacement meter is stored as f.
The total received light amount F is less than or equal to the maximum total received light amount Fmax × α, and
It is characterized by including a step of stopping scanning when Fmax is β or more, and brings the optical displacement meter closer to the object to be measured from a far point, and after passing the focus point,
Since the scanning is stopped, the focus point can be found reliably and promptly.

【００２６】請求項３の発明によれば、請求項２記載の
形状測定装置において、αを０＜α＜１とすることを特
徴とし、フォーカス地点を通過したことを判断している
ので、フォーカス地点を通過後、走査し過ぎて被測定物
に衝突することを防いでいる。According to the invention of claim 3, the shape measuring apparatus according to claim 2 is characterized in that α is set to 0 <α <1, and it is determined that the focus point has been passed. After passing the point, it is prevented from scanning too much and colliding with the object to be measured.

【００２７】請求項４の発明によれば、請求項２記載の
形状測定装置において、βを０＜β＜Ｆｍａｘとするこ
とを特徴とし、フォーカス地点を通過したことを確認し
ているので、フォーカス地点を通過する前に走査を終了
することがない。According to the invention of claim 4, in the shape measuring apparatus according to claim 2, β is set to 0 <β <Fmax, and it is confirmed that the focus point has been passed. The scan is never finished before passing the point.

【００２８】請求項５の発明によれば、前記２記載の形
状測定装置において、走査終了後記憶手段により記憶さ
れているＬｆをフォーカス地点とすることを特徴とし、
それぞれの光学変位計の受光量情報からフォーカス地点
を決定しているので、非常に簡易にフォーカス地点を決
定することができる。According to a fifth aspect of the present invention, in the shape measuring apparatus according to the second aspect, Lf stored by the storage means after scanning is used as the focus point.
Since the focus point is determined from the received light amount information of each optical displacement meter, the focus point can be determined very easily.

【図面の簡単な説明】[Brief description of drawings]

【図１】 本発明の一実施例を説明するための要部概略
図構成図である。FIG. 1 is a schematic configuration diagram of a main part for explaining an embodiment of the present invention.

【図２】 光学式変位計の変位と出力の関係図である。FIG. 2 is a relationship diagram of displacement and output of an optical displacement meter.

【図３】 光学式変位計と被測定物の位置関係図であ
る。FIG. 3 is a positional relationship diagram of an optical displacement meter and an object to be measured.

【図４】 本発明の一実施例を説明するための光学変位
計の移動量と受光量和Ｆの関係図である。FIG. 4 is a relationship diagram of a movement amount and a received light amount sum F of an optical displacement meter for explaining an embodiment of the present invention.

【図５】 本発明の一実施例を説明するためのフロー図
である。FIG. 5 is a flowchart for explaining one embodiment of the present invention.

【符号の説明】[Explanation of symbols]

１・・・被測定物 ２・・・第一の光学式変位計 ３・・・第二の光学式変位計 ４・・・第一の光学式変位計受光量取得手段 ５・・・第二の光学式変位計受光量取得手段 ６、７、８・・・走査手段 ９・・・Ｙ軸測定手段 １０・・・被測定物治具 １１・・・制御手段・記憶手段 1 ... DUT 2 ... The first optical displacement meter 3 ... Second optical displacement meter 4 ... First optical displacement meter received light amount acquisition means 5: Second optical displacement meter received light amount acquisition means 6, 7, 8 ... Scanning means 9 ... Y-axis measuring means 10 ... DUT jig 11 ... Control means / storage means

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】同じ測定点を測定する２つ以上の光学式変
位計を非接触プローブとして備え、測定を行う前に光学
式変位計の測定光が集光するフォーカス地点を取得する
必要がある形状測定装置において、それぞれの光学式変
位計の受光量Ｆ１，Ｆ２，・・・・,Ｆｎを取得する手
段と、光学式変位計を光軸方向に走査させる制御手段
と、光学式変位計の移動量を測定する手段と、前記受光
量和Ｆを演算する手段と、前記受光量和Ｆを記憶する手
段を有し、前記受光量和Ｆの演算結果に基づいてフォー
カス地点を決定することを特徴とする形状計測装置。1. A non-contact probe having two or more optical displacement gauges for measuring the same measurement point, and it is necessary to obtain a focus point where the measurement light of the optical displacement gauge is focused before performing the measurement. In the shape measuring device, means for acquiring the received light amounts F1, F2, ..., Fn of the respective optical displacement meters, control means for scanning the optical displacement meters in the optical axis direction, and A means for measuring the amount of movement, a means for calculating the received light amount sum F, and a means for storing the received light amount sum F are provided, and the focus point is determined based on the calculation result of the received light amount sum F. Characteristic shape measuring device. 【請求項２】請求項１記載の形状測定装置において、フ
ォーカス地点を決定する方法として、光学式変位計を
走査手段により被測定物の遠点に移動させる、徐々に
光学式変位計を被測定物に近づける方向に走査させる。
同時に光学式変位計の受光量Ｆ１,Ｆ２・・・,Ｆｎと
移動量Ｌを取得し、演算手段により受光量和Ｆ（＝Ｆ
１＋Ｆ２＋Ｆ３＋・・・・Ｆｎ）を演算し、記憶手段
により記憶している最大受光量和Ｆｍａｘと比較し、
記憶されているＦｍａｘより現在の受光量和Ｆが大きか
った場合、最大受光量和Ｆｍａｘとして現在の受光量和
Ｆ、最大受光量時移動量Ｌｆとして現在の光学式変位計
の移動量Ｌを記憶する。受光量和Ｆが最大受光量和Ｆ
ｍａｘ×α以下で、かつ、Ｆｍａｘがβ以上の場合走査
を停止する、という工程を含むことを特徴とする形状計
測装置。2. The shape measuring apparatus according to claim 1, wherein as a method of determining a focus point, an optical displacement meter is moved to a far point of an object to be measured by a scanning means, and the optical displacement meter is gradually measured. Scan in the direction that approaches the object.
At the same time, the amount of light received F1, F2, ..., Fn and the amount of movement L of the optical displacement meter are acquired, and the sum of the amount of received light F (= F
1 + F2 + F3 + ... Fn) is calculated and compared with the maximum received light amount sum Fmax stored by the storage means,
When the current light receiving amount sum F is larger than the stored Fmax, the current light receiving amount sum F is stored as the maximum light receiving amount sum Fmax, and the current movement amount L of the optical displacement meter is stored as the maximum light receiving amount movement amount Lf. To do. Sum of received light F is maximum sum of received light F
A shape measuring device comprising a step of stopping scanning when max × α or less and Fmax is β or more. 【請求項３】請求項２記載の形状測定装置において、α
を０＜α＜１とすることを特徴とする形状計測装置。3. The shape measuring device according to claim 2, wherein α
A shape measuring apparatus, wherein 0 <α <1. 【請求項４】請求項２記載の形状測定装置において、β
を０＜β＜Ｆｍａｘとすることを特徴とする形状計測装
置。4. The shape measuring device according to claim 2, wherein β
Is 0 <β <Fmax. 【請求項５】請求項２記載の形状測定装置において、走
査終了後記憶手段により記憶されているＬｆをフォーカ
ス地点とすることを特徴とする形状計測装置。5. The shape measuring apparatus according to claim 2, wherein the focus point is Lf stored by the storage means after the scanning is completed.