JPH035845Y2 - - Google Patents
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- Publication number
- JPH035845Y2 JPH035845Y2 JP2041484U JP2041484U JPH035845Y2 JP H035845 Y2 JPH035845 Y2 JP H035845Y2 JP 2041484 U JP2041484 U JP 2041484U JP 2041484 U JP2041484 U JP 2041484U JP H035845 Y2 JPH035845 Y2 JP H035845Y2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- reflected
- detector
- edge
- threshold
- Prior art date
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Links
- 238000001514 detection method Methods 0.000 claims description 62
- 238000006073 displacement reaction Methods 0.000 claims description 42
- 230000003287 optical effect Effects 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 18
- 238000005259 measurement Methods 0.000 claims description 11
- 238000010586 diagram Methods 0.000 description 7
- 230000004069 differentiation Effects 0.000 description 5
- 238000003708 edge detection Methods 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000011549 displacement method Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Measurement Of Optical Distance (AREA)
Description
【考案の詳細な説明】
本考案は、光学式表面変位検出回路に係り、特
に、遠隔物体の厚さや変位等を非接触で測定する
ことができる光学式表面変位検出装置に用いるの
に好適な、ビ−ム走査範囲の基準位置に対応して
配設された基準光検出素子から出力される基準信
号と、測定対象面によるビ−ム反射光のうち、ビ
−ム照射方向とは異なる設定方向の反射光のみを
受光するようにされた反射光検出素子から出力さ
れる反射信号の発生時間間隔から、測定対象面の
設定方向変位を求めるための光学式表面変位検出
回路の改良に関する。[Detailed description of the invention] The present invention relates to an optical surface displacement detection circuit, and is particularly suitable for use in an optical surface displacement detection device that can measure the thickness, displacement, etc. of a remote object without contact. , the reference signal output from the reference light detection element arranged corresponding to the reference position of the beam scanning range, and the beam reflected light from the measurement target surface, settings that differ from the beam irradiation direction. The present invention relates to an improvement in an optical surface displacement detection circuit for determining the displacement of a surface to be measured in a set direction from the generation time interval of a reflection signal output from a reflected light detection element configured to receive only reflected light in that direction.
産業界における生産の自動化、ロボツト導入等
に伴ない、計測のインプロセス化、高速度化、高
精度化が急速に優勢されており、赤熱した鉄板の
圧延工程における厚さのインプロセス測定のよう
に、遠隔物体の厚さや変位等を非接触で測定でき
る表面変位検出装置の必要性も大となつている。 With the automation of production and the introduction of robots in the industrial world, in-process measurement, higher speed, and higher accuracy are rapidly gaining ground. In addition, there is a growing need for a surface displacement detection device that can measure the thickness, displacement, etc. of a remote object in a non-contact manner.
このような非接触式の表面変位検出装置として
は、被測定物体に投射した光の反射光や散乱光を
変位に関する信号とする光学的変位方式を利用し
たもの、磁束変化、渦電流、容量変化等、電磁気
的場の効果を利用したもの、放射線の吸収度を利
用したもの、超音波を利用したもの等が提案され
ているが、被測定物体との設定距離を大きく取れ
るという点では、光学的方式を利用したもの（以
下、光学式表面変位検出装置と称する）が有利で
ある。 Such non-contact surface displacement detection devices include those that use an optical displacement method that uses reflected light and scattered light of the light projected onto the object to be measured as signals related to displacement, magnetic flux changes, eddy currents, capacitance changes, etc. etc., methods using electromagnetic field effects, methods using radiation absorption, methods using ultrasonic waves, etc. have been proposed, but optical An optical surface displacement detection device (hereinafter referred to as an optical surface displacement detection device) is advantageous.
この光学式表面変位検出装置としては、種々の
方式が提案されているが、その１つに、例えば第
１図に示す如く、レ−ザビ−ム発生器２０と、該
レ−ザビ−ム発生器２０から発生されたスポツト
状のレ−ザビ−ム２１を、等角速度で回転走査す
るための回転ミラ−２２と、該回転ミラ−２２に
よつて形成された回転走査ビ−ム２３が、基準位
置を走査したことを検出するための基準光検出素
子２４と、回転走査ビ−ム２３の測定対象面１０
による反射光のうち、測定対象面１０と垂直な方
向（変位測定方向）の反射光のみを通過させるス
リツト２６と、該スリツト２６を通過した反射光
の有無を検出するための反射光検出素子２８とを
備え、変位検出回路２９により測定される、前記
基準光検出素子２４から出力される基準信号と前
記反射光検出素子２８から出力される反射信号の
発生時間間隔、即ち、回転走査ビ−ム２３の走査
角度θから、測定対象面１０の上下方向変位Ｘを
求めるようにした、いわゆる、投射ビ−ム回転走
査方式によるものがある。 Various methods have been proposed as this optical surface displacement detection device, and one of them, for example, as shown in FIG. A rotating mirror 22 for rotating and scanning a spot-shaped laser beam 21 generated from a device 20 at a constant angular velocity, and a rotating scanning beam 23 formed by the rotating mirror 22. A reference light detection element 24 for detecting that the reference position has been scanned, and a measurement target surface 10 of the rotating scanning beam 23.
A slit 26 that allows only the reflected light in a direction perpendicular to the measurement target surface 10 (displacement measurement direction) to pass among the reflected light caused by the slit 26, and a reflected light detection element 28 for detecting the presence or absence of the reflected light that has passed through the slit 26. and the generation time interval between the reference signal output from the reference light detection element 24 and the reflection signal output from the reflected light detection element 28, which is measured by the displacement detection circuit 29, that is, the rotational scanning beam. There is a so-called projection beam rotation scanning method in which the vertical displacement X of the surface to be measured 10 is determined from the scanning angle .theta.
又、前出第１図に示した投射ビ−ム回転走査方
式における、回転走査ビーム２３の走査角度θと
変位量Ｘの関係が光学的に非線形となり、複雑な
補正が必要となるだけでなく、回転ミラ−２２と
測定対象面１０間の距離l1、l2、l3等を計算する
必要があるという問題点を解消するものとして、
出願人は既に実願昭58−139708において、第２図
に示す如く、前記回転ミラ−２２と測定対象面１
０の間に、前記回転ミラ−２２により扇状に回転
走査される回転走査ビ−ム２３を互いに平行な平
行走査ビ−ム３１とするためのコリメ−タレンズ
３０を挿入することによつて、回転走査ビ−ム２
３の走査角度θと測定対象面１０の変位量Ｘの間
に光学的な線形関係が成立するようにして、精度
の高い測定を簡単に行うことができるようにし
た、投射ビ−ム平行走査方式によるものを提案し
ている。 Furthermore, in the projection beam rotation scanning method shown in FIG. , to solve the problem that it is necessary to calculate the distances l 1 , l 2 , l 3 , etc. between the rotating mirror 22 and the surface to be measured 10,
As shown in FIG.
0, by inserting a collimator lens 30 for converting the rotating scanning beam 23 rotated in a fan shape by the rotating mirror 22 into parallel scanning beams 31 parallel to each other. scanning beam 2
Projection beam parallel scanning in which an optical linear relationship is established between the scanning angle θ of No. 3 and the displacement amount X of the measurement target surface 10, making it possible to easily perform highly accurate measurements. We are proposing a method based on this method.
しかしながら、前出第１図あるいは第２図に示
した光学式表面変位検出装置のいずれにおいて
も、測定精度を高精度とするためには、変位検出
回路２９で、基準信号と反射信号の発生時間間隔
を精度良く測定する必要があり、そのためには、
前記基準信号及び反射信号のエツジ位置あるいは
中心位置を精度良く求める必要がある。 However, in either of the optical surface displacement detection devices shown in FIG. 1 or 2, in order to achieve high measurement accuracy, the displacement detection circuit 29 must It is necessary to measure the distance accurately, and to do so,
It is necessary to accurately determine the edge position or center position of the reference signal and the reflected signal.
一方、光学式測定機器におけるエツジ検出装置
としては、出願人が既に特開昭58−173408、特願
昭58−102477、実願昭58−87424等において、
種々の方法を提案しているが、特開昭58−173408
で提案したような、測定対象物との相対移動時に
生ずる明暗に基づき、少なくとも２組の位相ずれ
信号を発生するよう移動面と略平行な面内に配設
された４個の受光素子からなるセンサと、前記各
組の位相ずれ信号の差を演算する第１及び第２の
演算手段と、これら第１及び第２の演算手段の出
力信号の差を演算する第３の演算手段及び和を演
算する第４の演算手段と、この第４の演算手段の
出力信号が所定レベルにある間に生じる、前記第
３の演算手段の出力信号と基準レベルのクロス信
号を出力する検知手段と、を含むエツジ検出装置
は、投影機には適しているものの、そのまま光学
式表面変位検出装置に用いるには、構成が非常に
複雑である。又、特願昭58−102477で提案したよ
うな、受光器を、被測定物の映像が進む方向に二
分割された２つの受光要素から形成すると共に、
これらの受光要素の出力信号を各々微分する微分
回路と、これら微分回路の出力信号の差を演算す
る差動回路と、この差動回路からの出力信号を参
照信号と比較して、被測定物のエツジとなる一点
を判別する判定回路と、を含むエツジ検出装置
は、２つの出力信号の波形がほぼ同じである高速
度走査型レ−ザ測長機には適しているものの、一
般に、散乱光の関係で見掛上の反射光径が異なる
ため、基準信号と反射信号の波形が大幅に異な
り、特に反射信号が非対称波形になり易い光学式
表面変位検出装置にそのまま用いるのには適して
いない。更に、実願昭58−87424で提案したよう
な、光線ビ−ムの一部を被測定物の直前で検知し
て、その光量変動を電気信号に変換して出力する
光量検知手段を設けると共に、この光量検知手段
を、その出力装置が判定装置における基準信号又
は受光器出力信号の補正信号となるように光量検
知手段に接続したエツジ検出装置も、やはり、光
学式表面変位検出装置にそのまま用いるのには適
していないという問題点を有していた。 On the other hand, as an edge detection device for an optical measuring instrument, the applicant has already published Japanese Patent Application Laid-Open No. 58-173408, Japanese Patent Application No. 58-102477, Utility Application No. 58-87424, etc.
Although various methods have been proposed, Japanese Patent Application Laid-Open No. 173408
It consists of four light-receiving elements arranged in a plane approximately parallel to the plane of movement so as to generate at least two sets of phase-shifted signals based on the brightness and darkness that occurs when moving relative to the object to be measured, as proposed in . A sensor, first and second calculation means for calculating the difference between the phase shift signals of each set, third calculation means for calculating the difference between the output signals of the first and second calculation means, and a sum. a fourth calculating means for calculating, and a detecting means for outputting a cross signal between the output signal of the third calculating means and a reference level, which occurs while the output signal of the fourth calculating means is at a predetermined level. Although the edge detection device included in the present invention is suitable for a projector, its configuration is too complicated to be used as is in an optical surface displacement detection device. In addition, as proposed in Japanese Patent Application No. 102477/1984, the light receiver is formed from two light receiving elements divided into two in the direction in which the image of the object to be measured travels.
A differentiating circuit that differentiates the output signals of these light-receiving elements, a differential circuit that calculates the difference between the output signals of these differentiating circuits, and a differential circuit that calculates the difference between the output signals of these differentiating circuits. An edge detection device including a determination circuit that determines a single point that is an edge of the Since the apparent diameter of the reflected light differs depending on the light, the waveforms of the reference signal and the reflected signal are significantly different, making it especially suitable for use as is in an optical surface displacement detection device where the reflected signal tends to have an asymmetrical waveform. do not have. Furthermore, as proposed in Utility Application No. 58-87424, a light amount detection means is provided which detects a part of the light beam just in front of the object to be measured, converts the fluctuation in light amount into an electrical signal, and outputs it. An edge detection device in which this light amount detection means is connected to a light amount detection means such that its output device serves as a reference signal in the determination device or a correction signal for the light receiver output signal can also be used as is in the optical surface displacement detection device. The problem was that it was not suitable for
又、基準信号と反射信号の波形の違いを克服す
るべく、各出力信号の中間点を直接捉え、それら
の間隔から時間間隔を決定することが考えられる
が、各出力信号の中間点を検出するに際して、例
えば２階微分を用いる方法は、回路が複雑になる
だけでなく、正確な中間点を求めるのが困難であ
るという問題点を有していた。 Also, in order to overcome the difference in waveform between the reference signal and the reflected signal, it is possible to directly capture the midpoint of each output signal and determine the time interval from those intervals, but it is possible to detect the midpoint of each output signal. In this case, for example, a method using second-order differentiation has the problem that not only the circuit becomes complicated, but also that it is difficult to find an accurate intermediate point.
本考案は、前記従来の問題点を解消するべくな
されたもので、基準信号や反射信号の中間点を直
接求めることなく、基準信号と反射信号の発生時
間間隔を、極めて簡単な回路で精度良く求めるこ
とができる光学式表面変位検出回路を提供するこ
とを目的とする。 The present invention was devised to solve the above-mentioned conventional problems, and it is possible to accurately determine the generation time interval between the reference signal and the reflected signal using an extremely simple circuit, without directly determining the intermediate point between the reference signal and the reflected signal. It is an object of the present invention to provide an optical surface displacement detection circuit that can be used to detect surface displacements.
本考案は、ビ−ム走査範囲の基準位置に対応し
て配設された基準光検出素子から出力される基準
信号と、測定対象面によるビ−ム反射光のうち、
ビ−ム照射方向とは異なる設定方向の反射光のみ
を受光するようにされた反射光検出素子から出力
される反射信号の発生時間間隔から、測定対象面
の設定方向変位を求めるための光学式表面変位検
出回路において、前記基準光検出素子の前方に配
置されたエツジ部材と、前記基準信号と交差する
第１閾値を発生する第１設定器と、前記反射信号
と２つの位置で交差する第２閾値を発生する第２
設定器と、前記基準信号と第１閾値の、前記エツ
ジ部材のエツジ位置に対応する交差位置を検出す
る第１検出器と、前記反射信号と第２閾値の２つ
の交差位置を検出する第２検出器と、前記第１検
出器で検出されるエツジ交差位置と前記第２検出
器で検出される前記反射信号と第２閾値の一方の
交差位置間に発生したクロツクパルス数を計数す
る第１カウンタと、前記エツジ交差位置と前記第
２検出器で検出される前記反射信号と第２閾値の
他方の交差位置間に発生したクロツクパルス数を
計数する第２カウンタと、両カウンタで計数され
た両パルス数を演算して、前記基準信号と反射信
号の発生時間間隔を求もる演算器と、を備えるこ
とにより、前記目的を達成したものである。 In the present invention, among the reference signal output from the reference light detection element arranged corresponding to the reference position of the beam scanning range and the beam reflected by the measurement target surface,
An optical method for determining the displacement of a surface to be measured in a set direction from the generation time interval of reflection signals output from a reflected light detection element that receives only reflected light in a set direction different from the beam irradiation direction. In the surface displacement detection circuit, an edge member disposed in front of the reference light detection element, a first setter that generates a first threshold that intersects the reference signal, and a first edge member that intersects the reflected signal at two positions. 2nd threshold value
a setting device; a first detector that detects a position of intersection between the reference signal and the first threshold value corresponding to an edge position of the edge member; and a second detector that detects a position of intersection between the reflected signal and the second threshold value. a detector; and a first counter that counts the number of clock pulses generated between an edge crossing position detected by the first detector and one crossing position of the reflected signal and a second threshold detected by the second detector. a second counter that counts the number of clock pulses generated between the edge crossing position and the other crossing position of the reflected signal detected by the second detector and the second threshold; and both pulses counted by both counters. The above-mentioned object is achieved by including a calculator that calculates the generation time interval of the reference signal and the reflected signal by calculating a number.
又、本考案の実施態様は、前記第１設定器及び
第２設定器が、前記基準光検出素子出力又は反射
光検出素子出力の最大値を保持し、該保持信号を
分圧して前記第１閾値又は第２閾値を発生するも
のとして、散乱光や電源変動等により基準信号や
反射信号の波高値が変動した場合であつても、エ
ツジ交差位置又は反射信号と第２閾値の２つの交
差位置を精度良く求めることができるようにした
ものである。 Further, in an embodiment of the present invention, the first setting device and the second setting device hold the maximum value of the reference light detection element output or the reflected light detection element output, and divide the holding signal to set the maximum value of the reference light detection element output or the reflected light detection element output. Even if the wave height value of the reference signal or reflected signal fluctuates due to scattered light or power fluctuations, etc., the threshold value or the second threshold value is generated. can be determined with high accuracy.
更に、本発明の他の実施様態は、前記第２検出
器を、前記反射信号と第２閾値を比較する比較器
と、該比較器出力の矩形波信号をデジタル処理し
て２つの交差位置に対応するパルス信号を発生す
るデジタル微分回路とから構成して、前記反射信
号と第２閾値の２つの交差位置を容易に検出でき
るようにしたものである。 Further, in another embodiment of the present invention, the second detector includes a comparator that compares the reflected signal with a second threshold value, and a rectangular wave signal output from the comparator that is digitally processed to produce two intersecting positions. It is constructed from a digital differentiator circuit that generates a corresponding pulse signal, so that it is possible to easily detect the two intersection positions of the reflected signal and the second threshold value.
本発明においては、基準光検出素子の前方にエ
ツジ部材を配置し、基準信号と第１閾値の前記エ
ツジ部材のエツジ位置に対応する交差位置と、反
射信号と第２閾値の一方の交差位置間に発生した
クロツクパルス数と、前記エツジ交差位置と、反
射信号と第２閾値の他方の交差位置間に発生した
クロツクパルス数を計数し、両パルス数を演算し
て、基準信号と反射信号の発生時間間隔を求める
ようにしたので、基準信号や反射信号の中間点を
直接求めることなく、従つて極めて簡単な回路に
より、基準信号と反射信号の発生時間間隔を精度
良く求めることができる。 In the present invention, an edge member is disposed in front of the reference light detection element, and between an intersection position of the reference signal and the first threshold value corresponding to the edge position of the edge member and an intersection position of one of the reflected signal and the second threshold value. The number of clock pulses generated between the edge crossing position and the other crossing position of the reflected signal and the second threshold are counted, and both pulse numbers are calculated to calculate the generation time of the reference signal and the reflected signal. Since the interval is determined, the generation time interval between the reference signal and the reflected signal can be determined with high precision using an extremely simple circuit without directly determining the midpoint between the reference signal and the reflected signal.
以下面を参照して、本考案の実施例を詳細に説
明する。 Embodiments of the present invention will be described in detail with reference to the following aspects.
本実施例は、第３図に示す如く、前出第２図に
示した従来例と同様の、レ−ザビ−ム発生器２０
と、回転ミラ−２２と、例えばフオトダイオ−ド
からなる基準光検出素子２４と、スリツト２６
と、例えばフオトダイオ−ドからなる反射光検出
素子２８と、変位検出回路29と、コリメ−タレン
ズ３０とを有する光学式表面変位検出装置におい
て、平行走査ビ−ム３１中の基準位置にミラ−４
０を設け、該ミラー４０により前記基準検出素子
２８にナイフエツジ４２及びレンズ４３を介して
レ−ザビ−ムを入射するように構成すると共に、
前記変位検出回路２９を、前記基準光検出素子２
４出力の基準信号S1及び前記反射光検出素子２８
出力の反射信号S2を各々増幅するアンプ４６、４
８と、前記基準信号S1と交差する第１閾値Vref1
を発生する第１設定器５０と、前記反射信号S2と
２つの位置で交差する第２閾値Vref2を発生する
第２設定器５２と、前記基準信号S1と第１閾値
Vref1の、前記ナイフエツジ４２のエツジ位置に
対応する交差位置P1を検出する第１検出器５４
と、前記反射信号S2と第２閾値Vref2の２つの交
差位置P21，P22を検出する第２検出器５６と、各
検出器５４、５６で検出される交差位置のうち、
エツジ交差位置P1及び反射信号S2と第２閾値
Vref2の２つの交差位置P21，P22を選択するため
のシフトレジスタ５８と、クロツクパルス発生器
６０と、第１検出器５４で検出されるエツジ交差
位置P1と第２検出器５６で検出される反射信号
S2と第２閾値Vref2の一方の交差位置P21間に発生
したクロツクパルス数Ａを計数する第１カウンタ
６２と、第１検出器５４で検出されるエツジ交差
位置P1と第２検出器５６で検出される反射信号
S2と第２閾値Vref2の他方の交差位置P22間に発生
したクロツクパルス数Ｂを計数する第２カウンタ
６４と、両カウンタ６２，６４で計数された両パ
ルス数を演算して、前記基準信号S1と反射信号S2
の発生時間間隔を求める演算器６６と、発生時間
間隔と変位量ｘを関係づける設定値を入力するさ
めの第３設定器６８と、該第３設定器６８の設定
値を利用して前記演算器６６出力の発生時間間隔
を変位に換算するための変位換算器７０と、該変
位換算器７０出力を表示するための表示器７２
と、から構成したものである。第３図において４
４は、反射光検出素子２８に入射される反射光を
集光するためのレンズである。 As shown in FIG. 3, this embodiment uses a laser beam generator 20 similar to the conventional example shown in FIG.
, a rotating mirror 22, a reference light detection element 24 made of, for example, a photodiode, and a slit 26.
In an optical surface displacement detection device having a reflected light detection element 28 made of, for example, a photodiode, a displacement detection circuit 29, and a collimator lens 30, a mirror 4 is placed at a reference position in a parallel scanning beam 31.
0, and the mirror 40 is configured so that the laser beam is incident on the reference detection element 28 via the knife edge 42 and the lens 43,
The displacement detection circuit 29 is connected to the reference light detection element 2.
4-output reference signal S1 and the reflected light detection element 28
Amplifiers 46 and 4 each amplify the output reflected signal S2 .
8, and a first threshold value Vref 1 that intersects with the reference signal S 1
a first setter 50 that generates a second threshold Vref 2 that intersects the reflected signal S 2 at two positions, a second setter 52 that generates a second threshold Vref 2 that intersects the reflected signal S 2 at two positions,
A first detector 54 detecting the intersection position P 1 corresponding to the edge position of the knife edge 42 of Vref 1
and a second detector 56 that detects the two crossing positions P 21 and P 22 of the reflected signal S 2 and the second threshold Vref 2 , and among the crossing positions detected by each of the detectors 54 and 56,
Edge intersection position P 1 , reflected signal S 2 and second threshold
A shift register 58 for selecting two crossing positions P 21 and P 22 of Vref 2 , a clock pulse generator 60, and an edge crossing position P 1 detected by the first detector 54 and detected by the second detector 56. reflected signal
A first counter 62 that counts the number of clock pulses A generated between one of the crossing positions P 21 between S 2 and the second threshold Vref 2 , and an edge crossing position P 1 detected by the first detector 54 and a second detector. Reflected signal detected at 56
A second counter 64 counts the number of clock pulses B generated between the other intersection point P 22 of S 2 and the second threshold Vref 2 , and the numbers of pulses counted by both counters 62 and 64 are calculated, Signal S 1 and reflected signal S 2
a calculator 66 for calculating the occurrence time interval of a displacement converter 70 for converting the generation time interval of the output of the device 66 into displacement; and a display 72 for displaying the output of the displacement converter 70.
It is composed of and. In Figure 3, 4
4 is a lens for condensing the reflected light incident on the reflected light detection element 28.
前記第１設定器５０及び第２設定器５２は、そ
れぞれ、前記アンンプ４６を介して入力される基
準光検出素子２４出力又は前記アンプ４８を介し
て入力される反射光検出素子２８出力の最大値を
保持するためのコンデンサ５０Ａ又は５２Ａと、
該コンデンサ５０Ａ又は５２Ａによる保持電圧
を、例えば1/2に分圧して前記第１閾値Vref1又
は第２閾値Vref2を発生する可変型の分圧抵抗５
０Ｂ又は５２Ｂと、から構成されている。 The first setter 50 and the second setter 52 respectively set the maximum value of the output of the reference light detection element 24 inputted via the amplifier 46 or the output of the reflected light detection element 28 inputted via the amplifier 48. a capacitor 50A or 52A for holding the
A variable voltage dividing resistor 5 that generates the first threshold value Vref 1 or the second threshold value Vref 2 by dividing the voltage held by the capacitor 50A or 52A by, for example, 1/2.
0B or 52B.
又、前記第１検出器５４は、前記アンプ４６を
介して入力される基準光検出素子２４出力と前記
第１閾値Vref1を比較する比較器５４Ａと、該比
較器５４Ａ出力の矩形波信号Sp1を微分して、基
準信号S1の立上がり、即ちエツジ交差位置に対応
するパルス信号P1を発生する微分回路５４Ｂと、
から構成されている。 The first detector 54 also includes a comparator 54A that compares the output of the reference photodetecting element 24 input via the amplifier 46 with the first threshold value Vref 1 , and a rectangular wave signal Sp output from the comparator 54A. 1 and generates a pulse signal P1 corresponding to the rising edge of the reference signal S1 , that is, the edge crossing position;
It consists of
更に、前記第２検出器５６は、前記アンプ４８
を介して入力される反射光検出素子２８出力と前
記第２閾値Vref2を比較する比較器５６Ａと、第
４図に示す如く、該比較器５６Ａ出力の矩形波信
号Sp2を微分し、一方を反転して論理和を取るこ
とによつて、又は、第５図に示す如く、矩形波信
号Sp2を微小時間だけ遅延して、元の信号との排
他的論理和を取ることによつて、反射信号S2の立
上り及び立下り、即ち、２つの交差位置に対応す
るパルス信号P21，P22を発生するデジタル微分回
路５６Ｂと、から構成されている。 Furthermore, the second detector 56 is connected to the amplifier 48.
As shown in FIG . 4, a comparator 56A compares the output of the reflected light detection element 28 input via the second threshold value Vref 2 , and as shown in FIG. By inverting and calculating the logical sum, or by delaying the square wave signal Sp2 by a minute time and calculating the exclusive logical sum with the original signal, as shown in Fig. 5. , and a digital differentiation circuit 56B that generates pulse signals P 21 and P 22 corresponding to the rise and fall of the reflected signal S 2 , that is, the two crossing positions.
本実施例における各部信号波形の例を第６図に
示す。図から明らかな如く、エツジ交差位置P1
と反射信号S2の立上りP21の時間間隔を計数した
パルス数Ａ及びエツジ交差位置P1と反射信号S2
の立下りP22の時間間隔を計数したパルス数Ｂを
加算して、２で割ることによつて、エツジ交差位
置P1と反射信号S2の中間点に対応するパルス数
（Ａ＋Ｂ）／２を、精度良く求めることができる。 FIG. 6 shows examples of signal waveforms at various parts in this embodiment. As is clear from the figure, the edge intersection position P 1
, the pulse number A calculated by counting the time interval between the rising edge P 21 of the reflected signal S 2 , the edge crossing position P 1 and the reflected signal S 2
The number of pulses corresponding to the midpoint between the edge crossing position P 1 and the reflected signal S 2 is obtained by adding the number B of pulses counted over the time interval of the falling edge P 22 of can be determined with high accuracy.
本実施例においては、第１閾値Vref1及び第２
閾値Vref2を、いずれも、基準信号S1の最大値又
は反射信号S2の最大値に応じて変動させるように
しているので、散乱光や電源変動等による出力信
号の波高値変動に拘らず、精度の良い測定を行う
ことができる。又、非対称波形である場合の中間
点を狙うことも容易である。なお、分圧抵抗５０
Ｂ、５２Ｂによる分圧比は１／２に限定されず、
又、第１閾値Vref1及び第２閾値Vref2を定電圧
設定とすることも可能である。 In this embodiment, the first threshold Vref 1 and the second
Since the threshold value Vref 2 is varied depending on the maximum value of the reference signal S 1 or the maximum value of the reflected signal S 2 , it is possible to adjust the threshold value Vref 2 regardless of fluctuations in the peak value of the output signal due to scattered light, power fluctuations, etc. , it is possible to perform accurate measurements. Furthermore, it is also easy to aim for the midpoint in the case of an asymmetric waveform. In addition, the voltage dividing resistor 50
The partial pressure ratio by B and 52B is not limited to 1/2,
Further, it is also possible to set the first threshold value Vref 1 and the second threshold value Vref 2 to constant voltage settings.
又、本実施例においては、第１カウンタ６２と
第２カウンタ６４の計数値の和（Ａ＋Ｂ）を２で
割ることによつて、クロツクパルス数と変位量を
従来と同様に対比させていたが、例えば、クロツ
クパルス数を従来の１／２とすることによつて、
２で割る演算を省略することも可能である。 Further, in this embodiment, the number of clock pulses and the amount of displacement are compared by dividing the sum (A+B) of the counts of the first counter 62 and the second counter 64 by 2, as in the conventional case. For example, by reducing the number of clock pulses to 1/2 of the conventional one,
It is also possible to omit the operation of dividing by 2.
なお、前記実施例においては、ナイフエツジ４
２を平行走査ビ−ム３１の走査方向上流側に配設
し、基準光検出素子２４で検出される基準信号の
立上りからエツジ交差位置を検出するようにして
いたが、エツジ交差位置を検出する方法はこれに
限定されず、例えば、ナイフエツジ４２を平行走
査ビ−ム３１の走査方向下流側に配設して、基準
信号の立下りからエツジ交差位置を検出するよう
に構成することも可能である。 In addition, in the above embodiment, the knife edge 4
2 was placed on the upstream side of the parallel scanning beam 31 in the scanning direction, and the edge crossing position was detected from the rising edge of the reference signal detected by the reference light detection element 24. The method is not limited to this, for example, it is also possible to arrange the knife edge 42 on the downstream side of the parallel scanning beam 31 in the scanning direction and detect the edge crossing position from the falling edge of the reference signal. be.
本考案は、実施例で示したような投射ビ−ム平
行走査方式の光学式表面変位検出装置に用いるの
に特に好適なものであるが、本考案の適用範囲は
これに限定されず、前出第１図に示したような投
射ビ−ム回転走査方式の光学式表面変位検出装置
や、他の方式の光学式表面変位検出装置、更に
は、一般の光学式測定機器にも同様に適用できる
ことは明らかである。 Although the present invention is particularly suitable for use in an optical surface displacement detection device using a projection beam parallel scanning method as shown in the embodiment, the scope of application of the present invention is not limited to this, and the invention is not limited to this. It can be similarly applied to optical surface displacement detection devices using a projection beam rotation scanning method as shown in Figure 1, other types of optical surface displacement detection devices, and even general optical measuring instruments. It is clear that it can be done.
以上説明したように、本考案によれば、基準信
号の中間点を求めることなく、又、反射信号の中
間点を直接求めることなく、基準信号と反射信号
の発生時間間隔を、極めて簡単な回路で精度良く
求めることができるという優れた効果を有する。 As explained above, according to the present invention, the generation time interval between the reference signal and the reflected signal can be calculated using an extremely simple circuit without determining the intermediate point of the reference signal or directly determining the intermediate point of the reflected signal. It has the excellent effect that it can be determined with high accuracy.
第１図は、従来の投射ビ−ム回転走査方式によ
る光学式表面変位検出装置の一例の構成を示すブ
ロツク線図、第２図は、出願人が既に提案した、
投射ビ−ム平行走査方式による光学式表面変位検
出装置の構成を示すブロツク線図、第３図は、本
考案に係る光学式表面変位検出回路の実施例が採
用された、光学式表面変位検出装置の構成を示す
ブロツク線図、第４図は、前記実施例で用いられ
ているデジタル微分回路の作用の一例を示す線
図、第５図は、同じくデジタル微分回路の作用の
他の例を示す線図、第６図は、前記実施例の各部
動作波形を示す線図である。
１０……測定対象面、２０……レ−ザビ−ム発
生器、２２……回転ミラ−、２４……基準光検出
素子、２６……スリツト、２８……反射光検出素
子、４２……ナイフエツジ、５０，５２……設定
器、５０Ａ，５２Ａ……コンデンサ、５０Ｂ，５
２Ｂ……分圧抵抗、５４，５６……検出器、５４
Ａ，５６Ａ……比較器、５４Ｂ……微分回路、５
６Ｂ……デジタル微分回路、５８……シフトレジ
スタ、６０……クロツクパルス発生器、６２，６
４……カウンタ、６６……演算器、S1……基準信
号、S2……反射信号、Vref1，Vref2……閾値、
P1……エツジ交差位置、P21，P22……交差位置、
Ａ，Ｂ……クロツクパルス数。
FIG. 1 is a block diagram showing the configuration of an example of an optical surface displacement detection device using a conventional projection beam rotation scanning method, and FIG.
FIG. 3 is a block diagram showing the configuration of an optical surface displacement detection device using a projection beam parallel scanning method. FIG. 4 is a block diagram showing the configuration of the device, FIG. 4 is a diagram showing an example of the operation of the digital differentiation circuit used in the above embodiment, and FIG. 5 is a diagram showing another example of the operation of the digital differentiation circuit used in the above embodiment. The diagram shown in FIG. 6 is a diagram showing the operation waveforms of each part of the embodiment. DESCRIPTION OF SYMBOLS 10... Surface to be measured, 20... Laser beam generator, 22... Rotating mirror, 24... Reference light detection element, 26... Slit, 28... Reflected light detection element, 42... Knife edge , 50, 52... Setting device, 50A, 52A... Capacitor, 50B, 5
2B...Voltage dividing resistor, 54, 56...Detector, 54
A, 56A... Comparator, 54B... Differential circuit, 5
6B...Digital differentiation circuit, 58...Shift register, 60...Clock pulse generator, 62,6
4...Counter, 66...Arithmetic unit, S1 ...Reference signal, S2 ...Reflected signal, Vref 1 , Vref 2 ...Threshold value,
P 1 ... Edge intersection position, P 21 , P 22 ... Intersection position,
A, B...Clock pulse number.
Claims (1)
れた基準光検出素子から出力される基準信号
と、測定対象面によるビ−ム反射光のうち、ビ
−ム照射方向とは異なる設定方向の反射光のみ
を受光するようにされた反射光検出素子から出
力される反射信号の発生時間間隔から、測定対
象面の設定方向変位を求めるための光学式表面
変位検出回路において、 前記基準光検出素子の前方に配置されたエツ
ジ部材と、 前記基準信号と交差する第１閾値を発生する
第１設定器と、 前記反射信号と２つの位置で交差する第２閾
値を発生する第２設定器と、 前記基準信号と第１閾値の、前記エツジ部材
のエツジ位置に対応する交差位置を検出する第
１検出器と、 前記反射信号と第２閾値の２つの交差位置を
検出する第２検出器と、 前記第１検出器で検出されるエツジ交差位置
と前記第２検出器で検出される前記反射信号と
第２閾値の一方の交差位置間に発生したクロツ
クパルス数を計数する第１カウンタと、 前記エツジ交差位置と前記第２検出器で検出
される前記反射信号と第２閾値の他方の交差位
置間に発生したクロツクパルス数を計数する第
２カウンタと、 両カウンタで計数された両パルス数を演算し
て、前記基準信号と反射信号の発生時間間隔を
求める演算器と、 を備えたことを特徴とする光学式表面変位検出
回路。 (2) 前記第１設定器及び第２設定器が、前記基準
光検出素子出力又は反射光検出素子出力の最大
値を保持し、該保持信号を分圧して前記第１閾
値又は第２閾値を発生するものとされている実
用新案登録請求の範囲第１項記載の光学式表面
変位検出回路。 (3) 前記第２検出器が、前記反射信号と第２閾値
を比較する比較器と、該比較器出力の矩形波信
号をデジタル処理して２つの交差位置に対応す
るパルス信号を発生するデジタル微分回路とか
ら構成されている実用新案登録請求の範囲第１
項記載の光学式表面変位検出回路。[Claims for Utility Model Registration] (1) Between the reference signal output from the reference light detection element arranged corresponding to the reference position of the beam scanning range and the beam reflected by the measurement target surface. , an optical system for determining the displacement of a surface to be measured in a set direction from the generation time interval of reflection signals output from a reflected light detection element configured to receive only reflected light in a set direction different from the beam irradiation direction. In the type surface displacement detection circuit, an edge member disposed in front of the reference light detection element, a first setter that generates a first threshold that intersects with the reference signal, and an edge member that intersects with the reflected signal at two positions. a second setting device that generates a second threshold; a first detector that detects an intersection position of the reference signal and the first threshold that corresponds to an edge position of the edge member; a second detector for detecting an edge intersection position detected by the first detector; and an edge intersection position detected by the first detector, the reflected signal detected by the second detector, and a second threshold value. a first counter that counts the number of clock pulses; a second counter that counts the number of clock pulses generated between the edge crossing position and the other crossing position of the reflected signal detected by the second detector and a second threshold; An optical surface displacement detection circuit comprising: a calculation unit that calculates the number of pulses counted by both counters to determine the time interval between the occurrences of the reference signal and the reflected signal. (2) The first setting device and the second setting device hold the maximum value of the reference light detection element output or the reflected light detection element output, and divide the holding signal to set the first threshold value or the second threshold value. The optical surface displacement detection circuit according to claim 1 of the utility model registration claim. (3) The second detector includes a comparator that compares the reflected signal with a second threshold, and a digital circuit that digitally processes the rectangular wave signal output from the comparator to generate a pulse signal corresponding to two intersection positions. The first claim for utility model registration consists of a differential circuit.
Optical surface displacement detection circuit described in .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2041484U JPS60134105U (en) | 1984-02-15 | 1984-02-15 | Optical surface displacement detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2041484U JPS60134105U (en) | 1984-02-15 | 1984-02-15 | Optical surface displacement detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60134105U JPS60134105U (en) | 1985-09-06 |
| JPH035845Y2 true JPH035845Y2 (en) | 1991-02-14 |
Family
ID=30510876
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2041484U Granted JPS60134105U (en) | 1984-02-15 | 1984-02-15 | Optical surface displacement detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60134105U (en) |
-
1984
- 1984-02-15 JP JP2041484U patent/JPS60134105U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60134105U (en) | 1985-09-06 |
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