JPS5826325Y2 - position detection device - Google Patents
position detection deviceInfo
- Publication number
- JPS5826325Y2 JPS5826325Y2 JP1977052262U JP5226277U JPS5826325Y2 JP S5826325 Y2 JPS5826325 Y2 JP S5826325Y2 JP 1977052262 U JP1977052262 U JP 1977052262U JP 5226277 U JP5226277 U JP 5226277U JP S5826325 Y2 JPS5826325 Y2 JP S5826325Y2
- Authority
- JP
- Japan
- Prior art keywords
- light
- light beam
- measured
- scanning
- receiving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Length Measuring Devices By Optical Means (AREA)
Description
【考案の詳細な説明】
本考案は、光束走査方式を利用した光束伝播方向の位置
検出装置に関するものである。[Detailed Description of the Invention] The present invention relates to a position detection device in the direction of propagation of a light beam using a light beam scanning method.
光束の走査による物体の外形寸法等の測定装置は、走査
方向の長さまたは位置を検出するものが一般的で、光束
伝播方向の位置検出は行なわれていない。Devices for measuring the external dimensions of an object by scanning a light beam generally detect the length or position in the scanning direction, but do not detect the position in the light beam propagation direction.
まず、従来の外形寸法測定装置の原理を第１図、第２図
を用いて簡単に説明する。First, the principle of a conventional external dimension measuring device will be briefly explained using FIGS. 1 and 2.
第１図は、走査型外形寸法測定装置の一般的ｆｊ原理ブ
ロック図である。FIG. 1 is a general fj principle block diagram of a scanning type external dimension measuring device.
図中１は光束走査装置で、被測定物２の方向に伝播する
光束３を一定幅Ａに一定速度で走査する。In the figure, reference numeral 1 denotes a beam scanning device, which scans a beam 3 propagating in the direction of the object 2 to be measured in a constant width A at a constant speed.
このときの走査される光束の位置を第２図ａの様に表わ
すことができる。The position of the scanned light beam at this time can be expressed as shown in FIG. 2a.
ただし、横軸ｔは時間を表わし、縦軸Ｂは走査方向の位
置座標で、その軸上の２およびＡはそれぞれ被測定物、
走査範囲の相対的ｔｘ位置を表わす。However, the horizontal axis t represents time, the vertical axis B represents the position coordinate in the scanning direction, and 2 and A on the axis represent the object to be measured, respectively.
Represents the relative tx position of the scan range.
上記走査によって第１図４の受光系で得られる信号Ｃは
第２図すに示す様に被測定物２によって光束が遮断され
た時間だけ低レベルになるパルス信号である。The signal C obtained by the light receiving system of FIG. 1 through the above scanning is a pulse signal that becomes low level only during the time when the light beam is interrupted by the object to be measured 2, as shown in FIG.
すなわちパルス信号Ｃの立上り、立下りは被測定物の位
置を表わし、パルス幅りは大きさを表わす。That is, the rising and falling edges of the pulse signal C represent the position of the object to be measured, and the pulse width represents the magnitude.
したがって、第１図５の処理回路によって被測定物の走
査方向の位置および外形寸法を知ることができる。Therefore, the position and external dimensions of the object to be measured in the scanning direction can be determined by the processing circuit shown in FIG.
このよ５な従来の外形寸法測定装置では、光束伝播方向
の位置の違いによって検出感度が異なるため、被測定物
が置かれる光束伝播方向Ｅ（第１図）の位置を制限する
必要が生じる。In such a conventional external dimension measuring apparatus, the detection sensitivity varies depending on the position in the light beam propagation direction, so it is necessary to limit the position in the light beam propagation direction E (FIG. 1) where the object to be measured is placed.
また高分解能測定では走査光束を微細にすることが望ま
れ、レンズを用いて光束を絞るため、ビームウェスト付
近で測定す−る必要が生じる。Furthermore, in high-resolution measurements, it is desired to make the scanning light beam minute, and since a lens is used to narrow down the light beam, it is necessary to measure near the beam waist.
ところが、従来の位置検出装置で、光束伝播方向の被測
定物の位置を検出しようとした場合、被測定物に光を照
射し、その散乱光を受けて光量を比較し光軸方向の位置
を検出するように構成されているので、被測定物の表面
に明暗がある、表面あらさが異る、表面性状に変動があ
るたどした場合、投光照射光束の有限なビーム径により
検出するため物体表面の明暗等の境界と位置とを区別す
るために測定精度をあげられなく、その分譲差を生ずる
。However, when attempting to detect the position of an object to be measured in the direction of light flux propagation using a conventional position detection device, the object is irradiated with light, receives the scattered light, and compares the amount of light to determine the position in the optical axis direction. Because it is configured to detect, if the surface of the object to be measured has brightness or darkness, different surface roughness, or variations in surface texture, it can be detected using the finite beam diameter of the projected light beam. The accuracy of measurement cannot be improved because it is necessary to distinguish between the boundaries and positions of brightness and darkness on the surface of an object, resulting in differences in distribution.
また、表面性状が変動すれば散乱反射光の指向特性の変
動により大きな誤差変動を生ずる。Furthermore, if the surface properties change, large error fluctuations will occur due to changes in the directional characteristics of the scattered reflected light.
本考案は上記要求に応じ、高分解能、高精度測定を可能
にするためビームウェストを中心とした光束伝播方向の
被測定物の位置を検出する位置検出装置を提供するもの
である。In response to the above-mentioned requirements, the present invention provides a position detection device that detects the position of an object to be measured in the direction of propagation of a light beam centered on the beam waist in order to enable high-resolution and high-precision measurement.
以下、本考案を第３図及び４図の実施例に従がって説明
する。Hereinafter, the present invention will be explained according to the embodiments shown in FIGS. 3 and 4.
第３図中６は平行光束を発生するレーザ等の光源、７は
その光束を入射し、出射角な鋸歯状的に掃引する偏向器
で、たとえば回転ミラー偏向器、超音波偏向器などであ
る。In Fig. 3, 6 is a light source such as a laser that generates a parallel light beam, and 7 is a deflector that receives the light beam and sweeps it in a sawtooth pattern at an output angle, such as a rotating mirror deflector or an ultrasonic deflector. .
８は偏向器７を出た光束を被測定物２へ照射する対物レ
ンズで、幾何光学的偏向点９と前側焦点とを等しく設置
する。Reference numeral 8 denotes an objective lens for irradiating the light flux exiting the deflector 7 onto the object to be measured 2, and the geometrical optical deflection point 9 and the front focal point are set equally.
その結果、レンズ８の出射光束は後側焦点にビームウェ
ストをもち、伝播方向が常に平行な状態で走査される。As a result, the emitted light beam from the lens 8 has a beam waist at the rear focal point and is scanned with its propagation direction always parallel.
被測定物２は、ビームウェストを中心とした前後一定範
囲内に置かれるものとする。The object to be measured 2 is placed within a certain range before and after the beam waist.
被測定物を走査して外形寸法等の情報を得た光束は集光
レンズ１０で集光されて受光素子１１へ入射する。A light beam that scans the object to be measured and obtains information such as external dimensions is condensed by a condenser lens 10 and enters a light receiving element 11 .
受光素子１１は、２分割された受光面をもち、それぞれ
の受光面に光束が入射したときそれぞれから受光信号が
得られるものを用い、受光面の分割境界が走査方向と垂
直にまた、受光面に前記偏向点の像ができる様に集光レ
ンズの後側焦点位置に配置される。The light-receiving element 11 has a light-receiving surface divided into two parts, and a light-receiving signal is obtained from each light-receiving surface when a light beam is incident on each light-receiving surface.The dividing boundary of the light-receiving surface is perpendicular to the scanning direction, and It is placed at the back focal position of the condenser lens so that an image of the deflection point is formed at the focal point.
上記の光学系により、ビームウェストが第２図と・同様
に第４図Ｆの様に走査された場合、受光素子から立下り
時、立上り時の異なる２つの信号Ｇ。When the beam waist is scanned by the above optical system as shown in FIG. 2 and as shown in FIG. 4F, two different signals G are generated from the light receiving element at falling and rising times.
Ｈが得られる。H is obtained.
この２つの信号を加算増幅器１２に加えると、第４図に
示す和信号■を得ることができ、そのパレス幅りから被
測定物の外形寸法を知ることができる。When these two signals are added to the summing amplifier 12, a sum signal (2) shown in FIG. 4 can be obtained, and the external dimensions of the object to be measured can be determined from the width of the pulse.
一方、本考案で検出しようとしている光束伝播方向の位
置は、得られた２つの信号の立下り時どおし、又は立上
りとおしの時間差を求めることによって知ることができ
る。On the other hand, the position in the light flux propagation direction that is to be detected in the present invention can be found by determining the time difference between the falling edges or rising edges of the two obtained signals.
時間差の求め方としては、第３図に示すように差動増幅
器１３とピーク検出器１４によるピーク検出方法と直接
的に位相検出器または時間検出器によって測定する方法
とがある。As shown in FIG. 3, methods for determining the time difference include a peak detection method using a differential amplifier 13 and a peak detector 14, and a method of directly measuring it using a phase detector or a time detector.
以下、ピーク検出方法について説明する。The peak detection method will be explained below.
差動増幅器から得られる、信号Ｇ、Ｈの立下り時および
立上り時のそれぞれから得られる差信号Ｊは、信号Ｇお
よびＨの立上り時と立下り時に正負異なる２つのピーク
をもつ。A difference signal J obtained from the differential amplifier from the falling and rising times of the signals G and H has two peaks with different positive and negative values at the rising and falling times of the signals G and H, respectively.
このピークは信号ＧとＨの位相差によるもので、位相差
は被測定物ノ位置カ光束伝播方向において、ビームウェ
ストを中心に正負異なって生じ、ビームウェストから離
れるに従がって大きくなる。This peak is due to the phase difference between the signals G and H. The phase difference occurs in positive and negative directions around the beam waist in the direction of propagation of the light beam at the position of the object to be measured, and increases as the distance from the beam waist increases.
従がってピーク検出器１４によって得られる出力信号に
は、ビームウェストを零として光束伝播方向の位置を表
わす。Therefore, the output signal obtained by the peak detector 14 represents the position in the beam propagation direction with the beam waist as zero.
第５図は走査光束のビームウェスト付近を拡大して図示
したもので、３はその光束、２は被測定物、１５はビー
ムウェストを表わす。FIG. 5 is an enlarged view of the vicinity of the beam waist of the scanning light beam, where 3 represents the light beam, 2 represents the object to be measured, and 15 represents the beam waist.
光束３は、前記説明した光学系により受光面に偏向点の
像を作るため、光束が偏向、走査されているにもかかわ
らず静止した状態で受光素子に入射する。The light beam 3 is incident on the light receiving element in a stationary state even though the light beam is deflected and scanned because an image of the deflection point is created on the light receiving surface by the optical system described above.
したがって、２分割された受光面には常に、光束の図面
上、平面的に仮定する中心線Ｋ（中心面）によって２分
割された光束りとＭとがそれぞれ入射する。Therefore, the light beam M and the light beam divided into two by the center line K (center plane), which is assumed to be two-dimensional in the diagram of the light beam, always enter the two-divided light receiving surface.
この光束によって得られる信号を光束りによって０１光
束ＭによってＨが得られるものとすると、被測定物２が
光束伝播方向Ｅにおいて、ビームウェスト１５に対して
後方にある場合、光束が図示した方向Ｂに走査されると
、被測定物の縁によって光束りが先に遮断され、信号Ｇ
が先に立下る。Assuming that the signal obtained by this luminous flux is 01 and H is obtained by the luminous flux M, when the object 2 to be measured is behind the beam waist 15 in the luminous flux propagation direction E, the luminous flux is directed in the direction B shown in the figure. When the object is scanned, the light beam is first interrupted by the edge of the object to be measured, and the signal G
falls first.
すなわち信号ＧがＨより進み位相となる。また、被測定
物が前方に置かれている場合は逆に遅れ位相となる。In other words, signal G leads H in phase. On the other hand, if the object to be measured is placed in front, the phase will be delayed.
２つの信号Ｇ、Ｈの立上り、立下り傾斜は、光束の走差
方向の光量分布と走査速度とによって定まる。The rising and falling slopes of the two signals G and H are determined by the light amount distribution in the scanning direction of the light beam and the scanning speed.
したがって、被測定物がビームウェストから離れるに従
がって、光量分布が変り、上記傾斜は小さくなり、信号
Ｇ、Ｈの位相差は大きくなる。Therefore, as the object to be measured moves away from the beam waist, the light amount distribution changes, the above-mentioned slope becomes smaller, and the phase difference between the signals G and H becomes larger.
この特性を第６図Ｎに示す。This characteristic is shown in FIG. 6N.
前記の、２つの信号Ｇ、Ｈの差信号Ｊに現われる２つの
ピークの波高値は、被測定物がビームウェストから十分
離れている場合は一定で、ビームウェスト付近では、回
折現象が強く現われるため前記２分割が不明瞭になり、
ビームウェストに近づくに従がって小さくなる。The wave height values of the two peaks appearing in the difference signal J between the two signals G and H are constant if the object to be measured is sufficiently far from the beam waist, but the diffraction phenomenon appears strongly near the beam waist. The two divisions become unclear,
It becomes smaller as it approaches the beam waist.
また、このピークの正、負極性は信号Ｇ、Ｈの位相差の
極性で変る他、信号Ｇ、Ｈの立上り、立下りとでも異な
る。Further, the positive and negative polarities of this peak vary depending on the polarity of the phase difference between the signals G and H, and also differ depending on the rising and falling edges of the signals G and H.
第６図Ｐは信号Ｇ、Ｈの立下り時に生ずるピーク値の特
性である。FIG. 6P shows the characteristics of the peak values that occur when the signals G and H fall.
第６図に示した様に、位相差の特性は広範囲に渡って良
好な比例関係を持続するが、ピーク値の特性は比例関係
は得られない。As shown in FIG. 6, the phase difference characteristics maintain a good proportional relationship over a wide range, but the peak value characteristics do not exhibit a proportional relationship.
しかし、ピーク検出による方法は、実用上要求される前
記ピークウェスト付近で高い感度が得られる他、光束の
走査が一定速度で行なわれない場合にも利用できる。However, the peak detection method not only provides high sensitivity near the peak waist, which is practically required, but can also be used when scanning of the light beam is not performed at a constant speed.
つまり、偏向器に振動ミラー型、たとえば音叉偏向器等
を用いた場合は正弦振動状の走査になり走査の速度が変
化して位相検出が困難な場合に効果を発揮する。In other words, when a vibrating mirror type deflector, such as a tuning fork deflector, is used as a deflector, scanning is performed in a sinusoidal manner, and the scanning speed changes, which is effective when phase detection is difficult.
このようにピーク検出による方法はビームウェスト近傍
の回折現象を利用したもので走査の形式に無関係に適用
できる。In this way, the peak detection method utilizes the diffraction phenomenon near the beam waist, and can be applied regardless of the type of scanning.
上記説明では、本考案の実施例として第３図にピーク検
出による方法を示したが、等速度走査の場合には位相検
出または時間検出でも実現できる。In the above description, a method using peak detection was shown in FIG. 3 as an embodiment of the present invention, but in the case of constant velocity scanning, phase detection or time detection can also be used.
つまり、第３図において差動増幅器およびピーク検出器
を位相検出器または時間検出器に置き替えることで可能
になる。That is, this becomes possible by replacing the differential amplifier and peak detector in FIG. 3 with a phase detector or a time detector.
以上の実施例の位置検出装置を、従来の外形寸法測定装
置等に組込むことによって、被測定物の光束伝播方向の
位置を明確にし、該測定装置の高性能化を可能にする。By incorporating the position detection device of the above embodiment into a conventional external dimension measuring device or the like, the position of the object to be measured in the light beam propagation direction can be clarified and the performance of the measuring device can be improved.
つまり、光束走査方式の分解能は光束の外径に反比例す
るためレンズを用いて光束を締る方法が適切で、被測定
物をビームウェスト付近に置く必要があり、また感度は
被測定物の位置に依存する要素を含むため、その位置を
検出して制限する必要がある他、高精度測定では、校正
用ゲージと比較測定を行なうことが一般的で、その条件
として同一位置での測定が望まれるからである。In other words, the resolution of the beam scanning method is inversely proportional to the outer diameter of the beam, so it is appropriate to use a lens to narrow the beam, and the object to be measured must be placed near the beam waist, and the sensitivity depends on the position of the object. In addition to the need to detect and limit the position of the gauge because it includes elements that depend on This is because
以上説明したように本考案の位置検出装置は、光束の走
査により通常の概念とは異なる光束伝播方向の位置検出
を可能にし、走査されているにもかかわらず静止像を形
成せしめ、従来の装置のように被測定物体上の光源の像
を形成してその像を２分して光量差をみるものと異なり
、受光素子が走査光束の実像を受光して、光束走査によ
る時間差で検出しているので、表面性状の影響を受ける
ことなく、高分解能、高精度に位置を検出でき、従来の
外形寸法測定装置等に容易に組み込むことができ、それ
らの装置の性能を著しく向上させることもできる。As explained above, the position detection device of the present invention enables position detection in a light beam propagation direction different from the usual concept by scanning the light beam, and forms a stationary image even though it is being scanned, making it possible to detect the position in the light beam propagation direction, which is different from the conventional concept. Unlike the method that forms an image of the light source on the object to be measured and divides the image into two to see the difference in light intensity, the light receiving element receives a real image of the scanning light beam and detects it based on the time difference due to the scanning of the light beam. Because of this, the position can be detected with high resolution and high accuracy without being affected by surface texture, and it can be easily incorporated into conventional external dimension measuring devices, etc., and can significantly improve the performance of those devices. .
第１図は、従来の外形寸法測定装置の原理ブロック図で
図中１は光束走査装置、２は被測定物、３は光束、４は
受光系、５は処理部、Ａは走査幅または走査範囲、Ｂは
走査方向、Ｃは受光信号、Ｅは光束伝播方向である。
第２図ａは、第１図の装置の光束の走査を図示したもの
でｔは時間である。
またｂは信号Ｃの波形でＤはそのパレス幅である。
第３図は本考案の実施例で、第４図はその信号波形であ
る。
図中６は光源、７は偏向器、９は偏向点、８，１０はレ
ンズ、１１は受光素子、１２は加算増幅器、１３は差動
増幅器、１４はピーク検出器、Ｇ及びＨは受光信号、■
は和信号、Ｊは差信号、Ｋは出力信号である。
第５図は走査光束のビームウェスト付近の拡大図で１５
はビームウェスト、Ｋは、光束３の中心線（中心面）、
Ｌ、Ｍは中心線Ｋによって２分割された光束である。
第６図は本考案の装置の特性を示したもので、横軸は、
光束伝播方向の被測定物の位置、縦軸は出力である。
曲線Ｐはピーク検出による特性、Ｎは位相検出による特
性である。FIG. 1 is a principle block diagram of a conventional external dimension measuring device. In the figure, 1 is a beam scanning device, 2 is an object to be measured, 3 is a beam of light, 4 is a light receiving system, 5 is a processing section, and A is a scanning width or a scanning section. B is the scanning direction, C is the received light signal, and E is the light beam propagation direction. FIG. 2a illustrates the scanning of the light beam of the device of FIG. 1, where t is time. Further, b is the waveform of the signal C, and D is its pulse width. FIG. 3 shows an embodiment of the present invention, and FIG. 4 shows its signal waveform. In the figure, 6 is a light source, 7 is a deflector, 9 is a deflection point, 8 and 10 are lenses, 11 is a light receiving element, 12 is a summing amplifier, 13 is a differential amplifier, 14 is a peak detector, G and H are light receiving signals , ■
is a sum signal, J is a difference signal, and K is an output signal. Figure 5 is an enlarged view of the vicinity of the beam waist of the scanning light beam.
is the beam waist, K is the center line (center plane) of the luminous flux 3,
L and M are luminous fluxes divided into two by the center line K. Figure 6 shows the characteristics of the device of the present invention, and the horizontal axis is
The position of the object to be measured in the light beam propagation direction, and the vertical axis is the output. Curve P is a characteristic based on peak detection, and curve N is a characteristic based on phase detection.
Claims (1)
る偏光器と；偏光器により走査された光束を被測定物へ
照射するために前記偏光器の偏光点と前側焦点とが＋致
する位置に配置されたレンズと；前記レンズの出射光束
を集束する集光レンズと：前記集光レンズの光軸上で受
光面が２分割され、分割されたそれぞれの受光面に光束
が入射したとき２つの受光信号を出力する前記焦光レン
ズの後側焦点位置に受光面が配置された受光素子と；該
受光素子から出力される２つの受光信号のそれぞれの立
上り時又は立下り時の時間差から光束伝播方向の被測定
物の位置を検出する処理回路とを備えた位置検出装置。a light source that generates a parallel light beam in the form of a beam; a polarizer that scans the light beam; and a polarization point of the polarizer and a front focus in order to irradiate the object to be measured with the light beam scanned by the polarizer; A condensing lens that focuses the emitted light beam of the lens; A light receiving surface of the condensing lens is divided into two on the optical axis, and the light beam enters each of the divided light receiving surfaces. A light-receiving element whose light-receiving surface is arranged at the rear focal position of the focusing lens that outputs two light-receiving signals; and a time difference between the rising and falling times of the two light-receiving signals output from the light-receiving element. A position detection device including a processing circuit that detects the position of an object to be measured in a direction of propagation of a light beam.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1977052262U JPS5826325Y2 (en) | 1977-04-26 | 1977-04-26 | position detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1977052262U JPS5826325Y2 (en) | 1977-04-26 | 1977-04-26 | position detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS53147857U JPS53147857U (en) | 1978-11-21 |
| JPS5826325Y2 true JPS5826325Y2 (en) | 1983-06-07 |
Family
ID=28943117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1977052262U Expired JPS5826325Y2 (en) | 1977-04-26 | 1977-04-26 | position detection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5826325Y2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4969351A (en) * | 1972-11-06 | 1974-07-04 |
-
1977
- 1977-04-26 JP JP1977052262U patent/JPS5826325Y2/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4969351A (en) * | 1972-11-06 | 1974-07-04 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53147857U (en) | 1978-11-21 |
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