JPS60185105A

JPS60185105A - Size measuring device utilizing light

Info

Publication number: JPS60185105A
Application number: JP4014684A
Authority: JP
Inventors: Shoichi Takei; 竹居　昭一; Tetsuo Yano; 哲夫矢野; Sakunori Oota; 策教太田
Original assignee: Ando Electric Co Ltd
Current assignee: Ando Electric Co Ltd
Priority date: 1984-03-02
Filing date: 1984-03-02
Publication date: 1985-09-20

Abstract

PURPOSE:To improve the accuracy of a size without measured errors, by adding an auxiliary circuit to a light detector, and obtaining the size of a part, where effects are small even though the beam diameter of parallel scanning light or the detecting sensitivity of the light detector is changed. CONSTITUTION:The detected voltage VP of parallel scanning light 1 by a light detector 4 is inputted to a divider 6. The detected voltage VP is obtained when the parallel scanning light 1 is converged by a condensor lens 3 and inputted to the light detector 4 under the state a material to be measured 2 is not present. The voltage VP is made to one half by the divider 6 and the result is inputted to a sample and hold circuit 7. A holding signal from a terminal 9 is added to the sample and hold circuit 7 when the light detector 4 detects the detected voltage VP. Therefore, the sample and hold circuit 7 holds the value of one half the detected voltage VP. From a comparator 8, an output is sent out in a range of a size Ls, in which the detected voltage V becomes one half the VP. By adding the auxiliary circuit, the measuring accuracy of the size of a part, in which the effects are small even though the beam diameter or the detecting sensitivity is changed, can be improved.

Description

[Detailed description of the invention]

（ａ）　発明の技術分野この発明は、被測定物に平行走査光を照射し、被測定物
によって中する影を光検出器で検出することにより、被
測定物の寸法を測定するようにした光による寸法測定装
、置についてのものである。（ｂ）　従来技術と問題点このような場合の従来装置の構成図の一例を第１図に示
す。第１図の１は平行走査光、２は被測定物、３は集光レン
ズ、４は光検出器である。平行走査光１を被測定物２に当てると、被測定物２によ
って影５ができる。光検出器４は平行走査光１を検出し、検出電圧Ｖを発生
ずる。この場合、平行走査光１が集光レンズ３に当たっ
ている部分からは・検出電圧Ｖが出るが、影５による部
分には平行走査光ｌが当たらないので、検出電圧Ｖは０
である。第１図の従来装置は被測定物２による影５の１法Ｌｌを
検出電圧Ｖが発生ずる寸法Ｌ２に置換して測定するもの
である− 次に、第１図の検出電圧Ｖの拡大図を第２図に示す。第２図のＶ３１とＶ３２は第１図の集光１／ンズ３によ
る光検出器４の検出電圧である。第２図から明らかなように、検出電圧Ｖ　３１　と検出
電圧Ｖ３２の端部はテーバ伏になっており、寸法Ｌ　２
　＞　”ｌ法Ｉ、４〉月決Ｌ３の関係になってもする。 χ」法１７．１は光検出器４の検出電圧Ｖが０のところ
の司法であり、寸法Ｌ４は寸法Ｌ２と司法Ｌ３の中間部
分の寸法である。 χＪ法１，２は第１図の影５の月決Ｌ１に対し、ｉ、　
２　＞　１．、　Ｉの関係になっている。これらは、平行走査光１がある径をもっているために起
こる現象である。さらに、平行走査光１のビーム径は水平位置により変化
することが、あり、平行走査光１の光／（ツーや光検出
器４の検出感度はエージノブなどで変化するので、検出
電圧■も変化するようになる。したがって、被測定物２の寸法ＬＬを光検出器４の検出
電圧Ｖからめようとすると、測定誤差になることがある
。（Ｃ）　発明の１」的この発明は、第１図の光検出器４に補助回路を追加する
ことにより、第１図の従来装置による測定誤差が少なく
なるようにすることを１」的とする。（ｄ′）発明の実施例まず、この発明による実施例の構成図を第３図に示す。第３図の６は分割器、７はサンプルボールド回路、８は
コンパレータである。分割器６は、光検出器４の検出電圧■を半分に分割する
。サンプル；ｊ、−ルド回路７は、端子(a) Technical field of the invention This invention measures the dimensions of an object to be measured by irradiating the object with parallel scanning light and detecting the shadow cast by the object with a photodetector. This is about an optical dimension measuring device. (b) Prior art and problems An example of a configuration diagram of a conventional device in such a case is shown in FIG. In FIG. 1, 1 is a parallel scanning beam, 2 is an object to be measured, 3 is a condenser lens, and 4 is a photodetector. When the parallel scanning light 1 is applied to the object 2 to be measured, a shadow 5 is formed by the object 2 to be measured. A photodetector 4 detects the parallel scanning light 1 and generates a detection voltage V. In this case, the detection voltage V is output from the part where the parallel scanning light 1 hits the condenser lens 3, but the detection voltage V is 0 because the parallel scanning light 1 does not hit the part due to the shadow 5.
It is. The conventional device shown in FIG. 1 measures the shadow 5 of the object to be measured 2 by replacing it with the dimension L2 where the detection voltage V is generated. is shown in Figure 2. V31 and V32 in FIG. 2 are voltages detected by the photodetector 4 by the condensing 1/lens 3 in FIG. 1. As is clear from FIG. 2, the ends of the detection voltage V 31 and the detection voltage V 32 are tapered down, and the dimension L 2
> ``l method I, 4> Even if the relationship is L3, χ'' method 17.1 is a law when the detection voltage V of the photodetector 4 is 0, and dimension L4 is This is the dimension of the middle part of L3. χJ method 1, 2 is for monthly decision L1 of shadow 5 in Figure 1, i,
2 > 1. , the relationship is I. These phenomena occur because the parallel scanning light 1 has a certain diameter. Furthermore, the beam diameter of the parallel scanning light 1 may change depending on the horizontal position, and the detection sensitivity of the light/( Therefore, when attempting to calculate the dimension LL of the object to be measured 2 from the detection voltage V of the photodetector 4, a measurement error may occur. The purpose of 1 is to reduce the measurement error caused by the conventional device shown in FIG. 1 by adding an auxiliary circuit to the photodetector 4 shown in the figure. (d') Embodiment of the Invention First, the invention A block diagram of an embodiment according to the present invention is shown in Fig. 3. In Fig. 3, 6 is a divider, 7 is a sample bold circuit, and 8 is a comparator. Divide sample;

【）からの、１．
−ルド信号により、分割器６の出力をサンプルホールド
する。コンパレータ８は、サンプルホールド回路７の出力と光
検出器４の検出電圧■を入力とし、検出電圧■の値が下
がりサンプルホールド回路７の出　゛力以下になると出
力する。次に、第３図の作用を第４図を参照しながら説明する。最初に平行走査光１による光検出器４の検出電圧Ｖｐを
分割器６に入力する。検出電圧Ｖｐは被測定物２がない状態で平行走査光１か
集光レンズ３により集光され光検出器４に入射する場合
に得られる。この検出電圧Ｖｒは分割器６で半分にされ、サンプル、
】−ルド回路７に入る。端子【）からのホールド信号は、光検出器４カ≦検出電
圧■Ｐを検出しているときにサンプル＋トールＦ回路７
に加えられる。したかって、−リーンプル；１．−ルド回路７は検出型
１１ｖＰの半分の値を１−ルドす、る。二Ｊノバン−タ８からは、第４図のように検出型Ｏ：、
　ＶかＶ＋・の半分以下になる寸法Ｌ５の範囲で出力か
出るようになる。すなわち、第３図の実施例は第４図の司法１，５を検出
するためのものである。一１法１．５を検出する理由は、次のとおりである。ビーｌ、径が小さい平行走査光１により得られる検出電
圧は、第５図の点ｚ−１２−ｘ３−ｚ１５　１　（ｉ−
１７−１８のように立上り、立下りか急な特Ｖ１．にな
る・被測定物か水平方向に移動したとき、被測定物に当る平
行走査光１のビーム径が大きくなると検出電圧は、第５
図の点１１−２１−１３−２２−２３−１６−２４−１
８のように立上り、立下りが緩やかな特性になる。しかし、両方の特性４も検出電圧ＶＰの半分の値に相当
する点１３と点１６を通過しており、平行走査光ｌのビ
ーム径が変化しても点］３と点１６の位置はほとんど変
化しないことかわかる。また、光検出器４の検出感度が良好なときや平行走査光
ｌの光パワーが大きいときに得られる検出電圧ＶＰは第
６図の点４１−４２−４３−４４−／＋５−４６−４７
−４８のように立上り、立下りが急な特性になる。集光レンズ３がｔ１７れてきた場合、光検出器４の検出
感度が悪くなってきた場合、平行走査光１の光パワーが
小さくなった場合には、検出電圧ｖ１゜は第６図の点５
　ｘ−５２−４’−４−４５−５３−５４のように出力
電圧が小さくなり、立」ニリ、立下りが緩やかな特性に
なる。しかし、第６図の両方の特性とも検出電圧Ｖｐの半分の
値に相当する点４３と点４６の間のＩＪ法と点５２と点
５３の間の司法はそれぞれＬ５になり、はとんど変化し
ないことが分る。この発明はこれらの点に着目したもので、第５図の点１
３と点１６の間、第６図の点４３と点４６の間、および
点５２と点５３の間の寸法に相当する第４図のＸＪ法Ｌ
５を検出するようにしたものである。（０）　発明の効果この発明は、光検出器４に補助回路を加えることにより
、平行走査光ｌのビーム径または光検出２：；４の検出
感度が変化しても、影響が少ない部分の・１法をめるよ
うにしているので、測定誤差の少ない１１法７１１１１
定装；ηを提供することができる。From [), 1.
- The output of the divider 6 is sampled and held by the field signal. The comparator 8 receives the output of the sample-and-hold circuit 7 and the detected voltage (2) of the photodetector 4 as input, and outputs an output when the value of the detected voltage (2) decreases to be less than the output of the sample-and-hold circuit 7. Next, the operation of FIG. 3 will be explained with reference to FIG. 4. First, the voltage Vp detected by the photodetector 4 due to the parallel scanning light 1 is input to the divider 6. The detection voltage Vp is obtained when the parallel scanning light 1 or the parallel scanning light 1 is focused by the condenser lens 3 and is incident on the photodetector 4 in the absence of the object to be measured 2 . This detection voltage Vr is halved by the divider 6, and the sample,
] - Enter the lead circuit 7. The hold signal from terminal [) is sample + tall F circuit 7 when detecting photodetector 4 ≦ detection voltage ■P.
added to. Therefore, - lean pull; 1. The -hold circuit 7 holds half the value of the detection type 11vP. From the 2J Novanta 8, the detection type O:, as shown in Figure 4.
Output will be produced within the range of dimension L5, which is less than half of V or V+. That is, the embodiment shown in FIG. 3 is for detecting judicial points 1 and 5 shown in FIG. The reason for detecting method 1.5 is as follows. The detection voltage obtained by parallel scanning beam 1 with a small diameter beam is expressed as the point z-12-x3-z15 1 (i-
17-18 with a sudden rise and fall or special V1. When the object to be measured moves in the horizontal direction, when the beam diameter of parallel scanning light 1 that hits the object increases, the detection voltage becomes
Points in the diagram 11-21-13-22-23-16-24-1
8, it has a characteristic of gradual rise and fall. However, both characteristics 4 also pass through points 13 and 16, which correspond to half the value of the detection voltage VP, and even if the beam diameter of the parallel scanning light l changes, the positions of points 3 and 16 are almost the same. I know it won't change. Furthermore, the detection voltage VP obtained when the detection sensitivity of the photodetector 4 is good or when the optical power of the parallel scanning light l is large is the point 41-42-43-44-/+5-46-47 in FIG.
-48, it has a characteristic with a steep rise and fall. When the condenser lens 3 becomes t17, when the detection sensitivity of the photodetector 4 becomes worse, or when the optical power of the parallel scanning light 1 becomes smaller, the detection voltage v1° changes to the point in Fig. 6. 5
As shown in x-52-4'-4-45-53-54, the output voltage becomes small, and the rise and fall characteristics become gentle. However, for both characteristics in FIG. 6, the IJ method between points 43 and 46, which corresponds to half the value of the detection voltage Vp, and the judicial method between points 52 and 53 are respectively L5, and the It turns out that it doesn't change. This invention focuses on these points, and points 1 in Figure 5
The XJ method L in FIG. 4 corresponds to the dimensions between point 3 and point 16, between point 43 and point 46 in FIG. 6, and between point 52 and point 53.
5 is detected. (0) Effects of the Invention This invention adds an auxiliary circuit to the photodetector 4, so that even if the beam diameter of the parallel scanning light l or the detection sensitivity of the photodetector 2:;・Since we use 1 method, 11 methods with less measurement error 71111
Standard specification: η can be provided.

[Brief explanation of the drawing]

第１図は従来装置の構成図、第２図は第１図の検出電圧Ｖの拡大図、第て３図はこの
発明による実施例の構成図、第４図は第３図の作用説明
図、明図。１・・・・・・平行走査光、２・・・・・被測定物、３
・・・　集光レンズ、４・・・・・光検出器、５・・・
・・影、６・・・分割器、７・・・・・・ザ／プル、ｊ
、−ルド回路、８・・・・フッパレータ、９・・・端子
、１０・・・端子。代理人　ブｔ・皿中　小　俣　欽　司第１図第２図第３因第４図第５図Fig. 1 is a block diagram of a conventional device, Fig. 2 is an enlarged view of the detected voltage V in Fig. 1, Fig. 3 is a block diagram of an embodiment according to the present invention, and Fig. 4 is an explanatory diagram of the operation of Fig. 3. , Mingzu. 1...Parallel scanning light, 2...Object to be measured, 3
... Condensing lens, 4... Photodetector, 5...
...shadow, 6...divider, 7...the/pull, j
, - field circuit, 8... Hupparator, 9... terminal, 10... terminal. Agent Butsu Saranaka Komata Kin Tsukasa Figure 1 Figure 2 Cause 3 Figure 4 Figure 5

Claims

[Claims] 1. Dimensions by light, in which the dimensions of the object to be measured are measured by irradiating the object to be measured with parallel scanning light and detecting the shadow caused by the object with a photodetector. The measuring device includes: a divider that halves the peak value of the output of the photodetector; a sample hold circuit that holds the output of the 0; f divider; and the peak value and the output of the sample hold circuit as inputs. A 1-method measuring device using light, comprising: a comparator, and measuring the 1J method of the object to be measured from a position where the output of the comparator 11; f is output.