JPH03158786A - Reflection type photoelectric sensor - Google Patents
Reflection type photoelectric sensorInfo
- Publication number
- JPH03158786A JPH03158786A JP1298582A JP29858289A JPH03158786A JP H03158786 A JPH03158786 A JP H03158786A JP 1298582 A JP1298582 A JP 1298582A JP 29858289 A JP29858289 A JP 29858289A JP H03158786 A JPH03158786 A JP H03158786A
- Authority
- JP
- Japan
- Prior art keywords
- light
- ratio
- signal
- receiving element
- semiconductor laser
- 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.)
- Pending
Links
- 239000004065 semiconductor Substances 0.000 claims abstract description 25
- 238000001514 detection method Methods 0.000 claims abstract description 13
- 238000010586 diagram Methods 0.000 description 7
- 238000013459 approach Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
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Abstract
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、反射型光電センナに関する。[Detailed description of the invention] (Industrial application field) The present invention relates to a reflective photoelectric sensor.
（従来の技術）
第３図は従来におけるコリメートタイプの反射型光電セ
ンサの構成図、第４図はそのブロック回路図である。(Prior Art) FIG. 3 is a configuration diagram of a conventional collimated type reflective photoelectric sensor, and FIG. 4 is a block circuit diagram thereof.
これらの図において、符号ｌはステム、２はステムＩに
一体に設けられるヒートシンク、３はヒートシンク２の
上面に取り付けられる光源としての半導体レーザー ４
はヒートシンク２の端面に取り付けられる対象物体から
の反射レーザー光を受光する信号検出用の受光素子、５
はステム１面に設けられ、半導体レーザー３の後端側か
ら出射されるレーザー光を直接受光するモニター用の受
光素子、８は半導体レーザー３からの出射光を平行光と
するマイクロフレネルレンズよりなるコリメートレンズ
、９はステムｌに一体に取り付けられ、上記のそれぞれ
の要素を内蔵するように設けられるパッケージ、ＩＯは
パッケージ９開口に設けられる透明板である。In these figures, reference numeral 1 indicates a stem, 2 indicates a heat sink provided integrally with the stem I, and 3 indicates a semiconductor laser as a light source attached to the upper surface of the heat sink 2. 4
5 is a light receiving element for signal detection that receives reflected laser light from a target object, which is attached to the end face of the heat sink 2;
8 is a monitor light-receiving element that is provided on one side of the stem and directly receives the laser light emitted from the rear end side of the semiconductor laser 3, and 8 is a micro Fresnel lens that converts the light emitted from the semiconductor laser 3 into parallel light. A collimating lens 9 is integrally attached to the stem l, and a package provided to house the above-mentioned respective elements, IO is a transparent plate provided in the opening of the package 9.
上記のような構成において、半導体レーザー３の前端面
からの出射光はコリメートレンズ８により平行光とされ
て対象物体であるワイヤー１１側に出射される。ワイヤ
ー１１の背面側には反射ミラー１２が設けられ、ワイヤ
ー１１が図のように存在する場合はワイヤー１１により
レーザー光の一部が散乱され、ワイヤー１１が存在しな
い場合には出射光は反射ミラー１２で反射されて受光素
子４側に戻ってくる。信号処理回路１５では、受光素子
４で受光される反射光量がしきい値を下回る場合に、ワ
イヤーＩＫの検出信号を出力するようになっている。In the above configuration, the light emitted from the front end face of the semiconductor laser 3 is converted into parallel light by the collimator lens 8, and is emitted toward the wire 11, which is the target object. A reflective mirror 12 is provided on the back side of the wire 11, and when the wire 11 is present as shown in the figure, part of the laser beam is scattered by the wire 11, and when the wire 11 is not present, the emitted light is reflected by the reflective mirror. 12 and returns to the light receiving element 4 side. The signal processing circuit 15 outputs a wire IK detection signal when the amount of reflected light received by the light receiving element 4 is less than a threshold value.
一方、半導体レーザー３の後端面からの出射光は受光素
子５で直接受光され、その受光信号はＡＰＣ回路Ｉ６に
与えられ、ＡＰＣ回路１６は半導体レーザー３が一定の
設定出力において出射を行うように、電源１４からの電
圧を適宜調整して駆動制御信号として半導体レーザー３
に与えるようになっている。半導体レーザー３が一定の
設定出力において出射を行わない場合、受光素子４にお
ける反射受光量か対象物品の存在に関係な（変動し、検
出動作が精度良く行われなくなる。On the other hand, the light emitted from the rear end surface of the semiconductor laser 3 is directly received by the light receiving element 5, and the received light signal is given to the APC circuit I6, which controls the semiconductor laser 3 to emit light at a constant set output. , the voltage from the power supply 14 is adjusted appropriately to output the semiconductor laser 3 as a drive control signal.
It is designed to be given to If the semiconductor laser 3 does not emit light at a constant set output, the amount of reflected light received by the light receiving element 4 will vary regardless of the presence of the target article, and the detection operation will not be performed accurately.
（発明が解決しようとする課題）
しかしながら、実際にはＡＰＣ回路１６を使用している
にしかかわらず検出信号が精度良く出力されない問題が
下記の理由により発生している。(Problems to be Solved by the Invention) However, in reality, despite the use of the APC circuit 16, a problem arises in which the detection signal is not output with high accuracy due to the following reasons.
すなわち、上記のＡＰＣ回路１６は、半導体レーザー３
が連続発振使用される場合に有効に機能し、上記の反射
型光電センサのように半導体レーザー３がパルス発振さ
れるものでは、与えられる受光信号が不連続であるので
どうしてもＡＰＣ回路１６における制御動作の追随性が
悪い。これにより、半導体レーザー３の出力が設定出力
を上回ったり下回ったりするものである。That is, the APC circuit 16 described above has the semiconductor laser 3
functions effectively when continuous oscillation is used, and when the semiconductor laser 3 is pulse-oscillated like the above-mentioned reflective photoelectric sensor, the control operation in the APC circuit 16 is unavoidable because the received light signal is discontinuous. tracking is poor. This causes the output of the semiconductor laser 3 to exceed or fall below the set output.
本発明は上記の問題点に鑑みてなしたもので、反射型光
電センサにおいて、半導体レーザーの出力が変化する場
合にも、対象物体の検出が精度良く行えるようにするこ
とを目的とする。The present invention has been made in view of the above problems, and an object of the present invention is to enable a reflective photoelectric sensor to detect a target object with high accuracy even when the output of a semiconductor laser changes.
（課題を解決するための手段）
本発明は、このような目的を達成するために、反射型光
電センサを、光源としての半導体レーザーと、前記半導
体レーザーから出射され、対象物体で反射された反射レ
ーザー光を受光する第１受光素子と、前記半導体レーザ
ーから出射されるレーザー光を直接受光する第２受光素
子と、前記第１と第２の受光素子からの受光信号におけ
る比を算出する比演算回路と、前記比演算回路で得られ
る比値をしきい値と比較し、その比較結果に基づいて対
象物体の検出信号を出力する信号処理回路とを備えてな
る構成とした。(Means for Solving the Problems) In order to achieve such an object, the present invention provides a reflective photoelectric sensor that includes a semiconductor laser as a light source and a reflection emitted from the semiconductor laser and reflected by a target object. a first light-receiving element that receives laser light; a second light-receiving element that directly receives laser light emitted from the semiconductor laser; and a ratio calculation that calculates a ratio between light-receiving signals from the first and second light-receiving elements. The present invention is configured to include a circuit, and a signal processing circuit that compares the ratio value obtained by the ratio calculation circuit with a threshold value and outputs a detection signal of the target object based on the comparison result.
（作用）
本発明によれば、第１受光素子で受光される反射レーザ
ー光と、第２受光素子で受光される直接のレーザー光と
におけるそれぞれの受光信号の比に基づいて対象物体の
検出を判定しているので、出射光の出力が変化する場合
もそれぞれの受光信号は同様の割合で変化し、これによ
り出射光の出力変化に影響を受けることなく物体の検出
が行われる。(Operation) According to the present invention, a target object is detected based on the ratio of the light reception signals of the reflected laser light received by the first light receiving element and the direct laser light received by the second light receiving element. Since the determination is made, even if the output of the emitted light changes, the respective light reception signals change at the same rate, so that object detection is performed without being affected by the change in the output of the emitted light.
（実施例）
以下、本発明の実施例を図面を参照して詳細に説明する
。第１図は本発明の反射型光電センサのブロック回路図
である。なお、反射型光電センサの機械的な組み立て構
成は、第３図に示す従来例のものと同様となる。従来例
における受光素子４が本発明の第１の受光素子となり、
受光素子５か第２の受光素子となる。(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block circuit diagram of a reflective photoelectric sensor of the present invention. Note that the mechanical assembly structure of the reflective photoelectric sensor is similar to that of the conventional example shown in FIG. The light receiving element 4 in the conventional example becomes the first light receiving element of the present invention,
The light receiving element 5 becomes the second light receiving element.
図において、符号２０は光源としての半導体レーザー
２１は半導体レーザー２０の電源、２２は上記半導体レ
ーザー２０から出射され、対象物体で反射された反射レ
ーザー光を受光する第１受光素子、２３は半導体レーザ
ー２０から出射されるレーザー光を直接受光する第２受
光素子、２５は第１と第２の受光素子２２．２３からの
受光信号における比を算出する比演算回路、２６は比演
算回路２５で得られる比値をしきい値と比較し、その比
較結果に基づいて対象物体の検出信号を出力する信号処
理回路である。In the figure, reference numeral 20 is a semiconductor laser as a light source.
21 is a power source for the semiconductor laser 20; 22 is a first light-receiving element that receives reflected laser light emitted from the semiconductor laser 20 and reflected by a target object; and 23 is a first light-receiving element that directly receives the laser light emitted from the semiconductor laser 20. a second light-receiving element; 25 is a ratio calculation circuit that calculates the ratio between the light-receiving signals from the first and second light-reception elements 22 and 23; 26 is a ratio calculation circuit that compares the ratio value obtained by the ratio calculation circuit 25 with a threshold; This is a signal processing circuit that outputs a detection signal of the target object based on the comparison result.
上記実施例の動作を説明する。The operation of the above embodiment will be explained.
今、半導体レーザー２０からの直接光を受光することに
より第２受光素子２３で流れる電流量をＡ１反射光を受
光することにより第１受光素子２２で流れる電流量をＢ
とし、その受光信号Ａ、Ｂが比演算回路２５に与えられ
ると、比演算回路２５ではその比値Ｂ／Ａ−αを算出し
、その比値信号αを信号処理回路２６に与える。信号処
理回路２６は、その比値信号における比値αを設定され
るしきい値と比較し、例えば、しきい値を上回る場合に
物体の検出信号Ｃを出力する。Now, by receiving the direct light from the semiconductor laser 20, the amount of current flowing in the second light receiving element 23 is A1, and by receiving the reflected light, the amount of current flowing in the first light receiving element 22 is B.
When the received light signals A and B are given to the ratio calculation circuit 25, the ratio calculation circuit 25 calculates the ratio value B/A-α, and gives the ratio value signal α to the signal processing circuit 26. The signal processing circuit 26 compares the ratio value α in the ratio value signal with a set threshold value, and outputs an object detection signal C when it exceeds the threshold value, for example.
上記において、出射光の出力が１．２倍に変化する場合
、受光信号はともに１．２Ａ、１．２Ｂとなり、比値は
上記と同様にαとなるもので、出射光の出力変化に影響
されることなく検出信号Ｃの出力が行われるものである
。In the above, if the output of the emitted light changes by 1.2 times, the received light signals will both be 1.2A and 1.2B, and the ratio value will be α as above, which will affect the change in the output of the emitted light. In this case, the detection signal C is outputted without being detected.
第２図は他の実施例を示すもので、この実施例において
は、第１図に示すものにおいて、第１と第２の受光素子
２２．２３と比演算回路２５との間に減算回路２７と加
算回路２８とのそれぞれを設け、減算回路２７と加算回
路２８とから比演算回路２５に減算受光信号Ａ−Ｂと加
算受光信号Ａ十Ｂとを与え、比演算回路２５ではＡ−Ｂ
／Ａ＋Ｂ＝１−α／１＋αが比値として算出され、その
比値ｌ−α／Ｉ＋αが信号処理回路２６でしきい値と比
較されるようになっている。第１図で示す実施例の構成
では、反射による受光信号Ｂが非常に小さい場合は比値
αが０に近付き、しきい値の設定、しきい値との比較が
困難なものとなるが、第２図のような構成とすれば受光
信号Ｂが小さい場合も１−α／１＋αは小さくならない
のでその問題が解消される。上記のように、信号処理回
路２６でしきい値と比較される比値は、αそのものであ
ってもよく、αの関数値であってもよい。FIG. 2 shows another embodiment, in which a subtraction circuit 27 is provided between the first and second light receiving elements 22, 23 and the ratio calculation circuit 25 in the embodiment shown in FIG. The subtraction circuit 27 and the addition circuit 28 provide the subtraction light reception signal A-B and the addition light reception signal A+B to the ratio calculation circuit 25.
/A+B=1-α/1+α is calculated as a ratio value, and the ratio value l-α/I+α is compared with a threshold value in the signal processing circuit 26. In the configuration of the embodiment shown in FIG. 1, when the received light signal B due to reflection is very small, the ratio α approaches 0, making it difficult to set the threshold value and compare it with the threshold value. With the configuration shown in FIG. 2, even if the received light signal B is small, 1-α/1+α will not become small, so this problem will be solved. As described above, the ratio value that is compared with the threshold value in the signal processing circuit 26 may be α itself or may be a function value of α.
（発明の効果）
したがって本発明よれば、第１受光素子で受光される反
射レーザー光と、第２受光素子で受光される直接のレー
ザー光とにおけるそれぞれの受光信号の比に基づいて対
象物体の検出を判定しているので、出射光の出力が変化
する場合もそれぞれの受光信号は同様の割合で変化し、
これにより出射光の出力変化に影響を受けることなく物
体の検出が精度良く行われるようになった。(Effects of the Invention) Therefore, according to the present invention, the target object is detected based on the ratio of the received light signals of the reflected laser light received by the first light receiving element and the direct laser light received by the second light receiving element. Since detection is determined, even if the output of the emitted light changes, each received light signal changes at the same rate.
As a result, objects can now be detected with high precision without being affected by changes in the output of the emitted light.
第１図と第２図とは本発明の実施例に関し、第１図は反
射型光電センサのブロック回路図、第２図は他実施例の
ブロック回路図である。
第３図は反射型光電センサの従来例の構成図、第４図は
同ブロック回路図である。
２０・・・半導体レーザー
２２・・第１受光素子、
２３・・・第２受光素子、
２５・・・比演算回路、
２６・・・信号処理回路。1 and 2 relate to an embodiment of the present invention; FIG. 1 is a block circuit diagram of a reflective photoelectric sensor, and FIG. 2 is a block circuit diagram of another embodiment. FIG. 3 is a configuration diagram of a conventional example of a reflective photoelectric sensor, and FIG. 4 is a block circuit diagram of the same. 20... Semiconductor laser 22... First light receiving element, 23... Second light receiving element, 25... Ratio calculation circuit, 26... Signal processing circuit.
Claims (1)
た反射レーザー光を受光する第１受光素子と、 前記半導体レーザーから出射されるレーザー光を直接受
光する第２受光素子と、 前記第１と第２の受光素子からの受光信号における比を
算出する比演算回路と、 前記比演算回路で得られる比値をしきい値と比較し、そ
の比較結果に基づいて対象物体の検出信号を出力する信
号処理回路と、 を備えてなる反射型光電センサ。(1) A semiconductor laser as a light source; a first light receiving element that receives reflected laser light emitted from the semiconductor laser and reflected by a target object; and a second light receiving element that directly receives the laser light emitted from the semiconductor laser. a light receiving element; a ratio calculation circuit that calculates a ratio between light reception signals from the first and second light reception elements; a ratio value obtained by the ratio calculation circuit is compared with a threshold value; and based on the comparison result, A reflective photoelectric sensor comprising: a signal processing circuit that outputs a detection signal of a target object;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1298582A JPH03158786A (en) | 1989-11-16 | 1989-11-16 | Reflection type photoelectric sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1298582A JPH03158786A (en) | 1989-11-16 | 1989-11-16 | Reflection type photoelectric sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03158786A true JPH03158786A (en) | 1991-07-08 |
Family
ID=17861609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1298582A Pending JPH03158786A (en) | 1989-11-16 | 1989-11-16 | Reflection type photoelectric sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03158786A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011124060A (en) * | 2009-12-10 | 2011-06-23 | Yazaki Corp | Electric wire position detecting device of terminal crimping machine |
| KR20150052523A (en) | 2013-11-06 | 2015-05-14 | 완주군 | Bread or cookie containing taro and manufacturing method of the same |
| CN110926508A (en) * | 2019-11-28 | 2020-03-27 | 北京大学深圳研究生院 | Active driving type photoelectric sensor, front end circuit and driving method |
-
1989
- 1989-11-16 JP JP1298582A patent/JPH03158786A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011124060A (en) * | 2009-12-10 | 2011-06-23 | Yazaki Corp | Electric wire position detecting device of terminal crimping machine |
| KR20150052523A (en) | 2013-11-06 | 2015-05-14 | 완주군 | Bread or cookie containing taro and manufacturing method of the same |
| CN110926508A (en) * | 2019-11-28 | 2020-03-27 | 北京大学深圳研究生院 | Active driving type photoelectric sensor, front end circuit and driving method |
| CN110926508B (en) * | 2019-11-28 | 2021-11-19 | 北京大学深圳研究生院 | Active driving type photoelectric sensor, front end circuit and driving method |
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