JPH01175138A - Permeation type photoelectric switch - Google Patents
Permeation type photoelectric switchInfo
- Publication number
- JPH01175138A JPH01175138A JP33565387A JP33565387A JPH01175138A JP H01175138 A JPH01175138 A JP H01175138A JP 33565387 A JP33565387 A JP 33565387A JP 33565387 A JP33565387 A JP 33565387A JP H01175138 A JPH01175138 A JP H01175138A
- Authority
- JP
- Japan
- Prior art keywords
- light
- light receiving
- receiving section
- lens
- 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.)
- Pending
Links
- 230000002093 peripheral effect Effects 0.000 claims abstract description 28
- 238000001514 detection method Methods 0.000 claims abstract description 27
- 230000003287 optical effect Effects 0.000 claims description 22
- 230000005540 biological transmission Effects 0.000 claims description 11
- 238000003384 imaging method Methods 0.000 claims description 7
- 238000007493 shaping process Methods 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 19
- 230000000903 blocking effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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- Switches Operated By Changes In Physical Conditions (AREA)
Abstract
Description
【発明の詳細な説明】
（イ）産業上の利用分野
この発明は、広い視野内の、例えば微小物体の有無を光
の回折現象を利用して検出する透過形光電スイッチに関
する。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a transmission type photoelectric switch that detects the presence or absence of, for example, a minute object within a wide field of view by utilizing a light diffraction phenomenon.
（ロ）従来の技術
従来の広視野光電スイッチは、光源にＬＥＤアレイ或い
は蛍光灯を使用し、受光素子としてはＣＣＤを使用して
いる。つまり、複数のＬＥＤ （発光ダイオード）を並
列配置したＬＥＤアレイを使用することで投光領域を広
げる一方、受光側はＬＥＤアレイに対応してＣＣＤライ
ンセンサを配置し、検出物体の検出範囲を広げている。(B) Prior Art A conventional wide-field photoelectric switch uses an LED array or a fluorescent lamp as a light source, and uses a CCD as a light receiving element. In other words, by using an LED array in which multiple LEDs (light emitting diodes) are arranged in parallel, the light emitting area is expanded, while on the light receiving side, a CCD line sensor is placed in correspondence with the LED array to expand the detection range of the detected object. ing.
投光領域内に遮光物（被検出物体）が存在しない時は、
投光素子から投射された投光綿はそのまま受光素子に受
光される。この場合、受光素子は検出信号を出力しない
。一方、投光領域内に遮光物が存在する時は、投光線が
遮光物に遮られ、受光素子は投光線を受光しない。これ
により、受光素子が検出信号を出力する。When there is no shielding object (object to be detected) within the light emitting area,
The light emitted from the light emitting element is directly received by the light receiving element. In this case, the light receiving element does not output a detection signal. On the other hand, when a light blocking object exists within the light projection area, the light beam is blocked by the light blocking object and the light receiving element does not receive the light beam. As a result, the light receiving element outputs a detection signal.
（ハ）発明が解決しようとする問題点
従来の透過形光電スイッチは、光源にＬＥＤアレイを使
用し、受光側にＣＣＤラインセンサを使用している。こ
のため、光源が大型化し余計な場所を取る不利がある。(C) Problems to be Solved by the Invention Conventional transmission type photoelectric switches use an LED array as a light source and a CCD line sensor on the light receiving side. This has the disadvantage that the light source becomes large and takes up unnecessary space.
また、受光部は結像レンズとラインセンサを用いている
ため、ピントの合う距離範囲が限定され、所謂焦点深度
が浅い不利がある。また、ＣＣＤラインセンサを駆動す
るための受光回路が複雑でコスト高となる欠点がある。Furthermore, since the light receiving section uses an imaging lens and a line sensor, the distance range that can be focused is limited, and there is a disadvantage that the so-called depth of focus is shallow. Another disadvantage is that the light receiving circuit for driving the CCD line sensor is complicated and costly.
更に、このＣＣＤラインセンサは、スキャン方式である
ため、応答速度が遅い欠点がある。仮に、ＣＣＤライン
センサに変えて、ＰＤアレイ（フォトダイオードアレイ
）を使用した場合、応答速度は速くなる反面、広視野で
微小物体を検出するにはＰＤ数を多くしなければならず
、この場合、受光回路が一層複雑となりコスト高となる
等、幾多の不利があった。Furthermore, since this CCD line sensor uses a scanning method, it has a drawback of slow response speed. If a PD array (photodiode array) is used instead of a CCD line sensor, the response speed will be faster, but the number of PDs must be increased to detect minute objects in a wide field of view. , there were many disadvantages such as the light receiving circuit becoming more complicated and the cost increasing.
この発明は、以上のような問題点を解消させ、光源が小
さく場所を取らず、しかも広視野内に存在する微小物体
の検出晴度が高く、安価な透過形光ミスインチを提供す
ることを目的とする。The present invention solves the above-mentioned problems and provides an inexpensive transmission type optical misinch that has a small light source that does not take up much space, has high brightness for detecting minute objects existing within a wide field of view, and is inexpensive. purpose.
（ニ）問題点を解決するための手段及び作用この目的を
達成させるために、この発明の透過形光電スイッチでは
、次のような構成としている。(d) Means and operation for solving the problem In order to achieve this object, the transmission type photoelectric switch of the present invention has the following configuration.
透過形光電スイッチは、点光源に近い投光素子と、投光
素子が投射する光を広視野光線にする投光レンズと、広
視野光線を結像レンズを介して受光する受光素子とから
なり、前記受光素子の受光面は非回折光を受光する中心
受光部と、回折光を受光する周辺受光部とから構成し、
中心受光部の出力をゲート信号として周辺受光部の受光
部を同期検出することで、検出物体のを無を判別し検出
信号を出力するように構成されている。Transmissive photoelectric switches consist of a light emitting element that is close to a point light source, a light emitting lens that converts the light projected by the light emitting element into a wide-field beam, and a light-receiving element that receives the wide-field beam through an imaging lens. , the light-receiving surface of the light-receiving element is composed of a central light-receiving part that receives undiffracted light and a peripheral light-receiving part that receives diffracted light;
By synchronously detecting the light receiving parts of the peripheral light receiving parts using the output of the central light receiving part as a gate signal, it is configured to determine whether there is a detected object or not and output a detection signal.
このような構成を有する透過形光電スイッチでは、受光
素子の受光面が非回折光受光用の中心受光部と、回折光
受光用の周辺受光部とから構成されている。中心受光部
は、受光面の中央部に、つまり結像レンズの焦点面に対
応する中央部に設けられ、周辺受光部はこの中心受光部
の周辺に、それぞれ独立して設けられている。In a transmission type photoelectric switch having such a configuration, the light receiving surface of the light receiving element is composed of a central light receiving section for receiving non-diffracted light and a peripheral light receiving section for receiving diffracted light. The central light-receiving section is provided at the center of the light-receiving surface, that is, at the center corresponding to the focal plane of the imaging lens, and the peripheral light-receiving sections are provided independently around the center light-receiving section.
例えば、投光領域に検出物体（微小物体）が存在しない
場合を想定すると、受光面上の光強度の分布は受光面中
央部にのみ集中する。この集中する光強度分布範囲は中
心受光部で受光される。中心受光部では集中光を受光す
ることでゲート信号を出力する。ここでは、微小物体が
存在せず回折現象が生じていないため、周辺受光部は全
く回折光を受光しない。つま、す、周辺受光部は受光信
号を出力しない。従って、この場合、検出信号は出力さ
れない。For example, assuming that there is no detection object (microscopic object) in the light projection area, the light intensity distribution on the light receiving surface is concentrated only at the center of the light receiving surface. This concentrated light intensity distribution range is received by the central light receiving section. The central light receiving section outputs a gate signal by receiving concentrated light. Here, since there is no minute object and no diffraction phenomenon occurs, the peripheral light receiving section does not receive any diffracted light. The peripheral light-receiving section does not output a light-receiving signal. Therefore, in this case, no detection signal is output.
仮に、投光領域に光を遮る微小物体が存在する場合、こ
の微小物体により光の回折現象が生じ、受光面上の光強
度の分布は中心受光部は勿論、周辺受光部にも回折光が
入射する。中心受光部は、ゲート信号を出力し、周辺受
光部は受光信号を出力する。ここにおいて、回折光を受
光する周辺受光部の受光量が同期検出され、検出信号が
出力される。If there is a microscopic object blocking the light in the light projection area, this microscopic object will cause a light diffraction phenomenon, and the light intensity distribution on the light receiving surface will be such that the diffracted light will be reflected not only in the central light receiving area but also in the peripheral light receiving areas. incident. The central light receiving section outputs a gate signal, and the peripheral light receiving section outputs a light reception signal. Here, the amount of light received by the peripheral light receiving section that receives the diffracted light is synchronously detected and a detection signal is output.
この発明では、光源として点光源に近い、例えばＬＥＤ
（発光ダイオード）を使うから、光源の大型化が解消さ
れる。また、受光素子として、例えばＰＤ（フォトダイ
オード）を使用するため、受光回路が簡単で応答速度も
速く、安価な光電スイッチを捉供し得る。In this invention, the light source is close to a point light source, for example, an LED.
(Light-emitting diodes) are used, eliminating the need for larger light sources. Further, since a PD (photodiode), for example, is used as the light receiving element, the light receiving circuit is simple, the response speed is fast, and an inexpensive photoelectric switch can be provided.
（ホ）実施例
第２図は、この発明に係る透過形光電スイッチの基本光
学系を示す概略構成図である。(E) Embodiment FIG. 2 is a schematic diagram showing the basic optical system of a transmission type photoelectric switch according to the present invention.
透過形光電スイッチは、投光素子１と、受光素子５とを
一定距離を開いて対向状に配置し、投光素子１側に投光
レンズ２、受光素子５側に受光レンズ４をそれぞれ配置
している。投光素子１は、ＬＤ（半導体レーザ）或いは
ＬＥＤ （発光ダイオード）の点光源に近いものを使用
する。この光源の面積は、可能な限り小さい方が後述す
る回折光の分離において有利である。この投光素子１の
配置は、投光レンズ２の焦点位置よりも僅かに近（配置
させである。これにより、投光レンズ２から、やや拡が
った光ビーム３が射出される。光ビーム（投光線）３は
、例えば略平行光線或いは扇状に拡がるスリット光線と
して射出される。受光レンズ４は、例えばフーリエ変換
レンズ等の一般的な結像レンズであり、受光素子５の受
光面は、投光ビーム３の焦点位置（最もスポットサイズ
の小さくなる距離）に配置されている。The transmission type photoelectric switch has a light emitting element 1 and a light receiving element 5 arranged facing each other with a certain distance apart, and a light emitting lens 2 is arranged on the light emitting element 1 side and a light receiving lens 4 is arranged on the light receiving element 5 side. are doing. As the light projecting element 1, an LD (semiconductor laser) or an LED (light emitting diode), which is close to a point light source, is used. It is advantageous for the area of this light source to be as small as possible in separating diffracted light, which will be described later. The light projecting element 1 is arranged slightly closer than the focal point of the light projecting lens 2. As a result, a slightly expanded light beam 3 is emitted from the projecting lens 2.The light beam ( The light emitting light beam) 3 is emitted as, for example, a substantially parallel light beam or a slit light beam that spreads in a fan shape.The light receiving lens 4 is a general imaging lens such as a Fourier transform lens, and the light receiving surface of the light receiving element 5 is It is arranged at the focal position of the light beam 3 (the distance where the spot size is the smallest).
受光素子５は、ＰＤ（フォトダイオード）であり、その
チップは第１図に示すように構成されている。つまり、
受光素子５の受光面は中央部に非回折光を受光する中心
受光部５１と、この中心受光部５１の周辺に、回折光を
受光する周辺受光部５２とから構成され、中心受光部５
１と周辺受光部５２は、それぞれ独立して信号を得るこ
とができるように設定しである。The light receiving element 5 is a PD (photodiode), and its chip is constructed as shown in FIG. In other words,
The light-receiving surface of the light-receiving element 5 is composed of a center light-receiving section 51 that receives non-diffracted light at the center, and a peripheral light-receiving section 52 that receives diffracted light around the center light-receiving section 51.
1 and the peripheral light receiving section 52 are set so that signals can be obtained independently from each other.
実施例では、例えば投光素子ｌは波長０．８μｍのＬＤ
とし、投光素子１と投光レンズ２間の焦点距離ｆ１を１
０＋ｎｍ、受光レンズ４の直径りを１０ｍｍ、受光レン
ズ４と受光素子５との焦点距離ｆ２を２０ｍｎ＋、投光
ビーム３の受光素子側における拡がり幅Ｗを３０ｍｍに
設定している（第２図参閘）。また、第１図に示す受光
素子５の受光面の１ｉｔ・横辺のそれぞれの長さＡは１
ｍｍとし、面内中央、つまり中心受光部５１径ａは２
０μｍに設定しである。In the embodiment, for example, the light projecting element l is an LD with a wavelength of 0.8 μm.
The focal length f1 between the light emitting element 1 and the light emitting lens 2 is 1.
0+nm, the diameter of the light-receiving lens 4 is set to 10 mm, the focal length f2 between the light-receiving lens 4 and the light-receiving element 5 is set to 20 mm+, and the spread width W of the emitted beam 3 on the light-receiving element side is set to 30 mm (see Figure 2). lock). Furthermore, the length A of each side of the light receiving surface of the light receiving element 5 shown in FIG. 1 is 1
mm, and the in-plane center, that is, the diameter a of the center light receiving part 51, is 2
It is set to 0 μm.
第３図は、実施例透過形光電スイッチの回路構成を示す
ブロック図である。FIG. 3 is a block diagram showing the circuit configuration of the transmissive photoelectric switch according to the embodiment.
投光器には、発振器１１が備えてあり、発光ダイオード
１はパルス変調光を投射する。これにより、外乱光によ
る悪影響が防止できる。このパルス変調光を受光素子（
中心受光部５１、周辺受光部５２）５が受光した時、増
幅回路１２．１２ａがパルス変調光を増幅する。この増
幅回路１２．１２ａは交流結合されており、定常的外乱
光は増幅せず、パルス変調光のみを増幅するように設定
しである。波形整形回路１３．１３ａでは、増幅された
パルス変調光を波形整形する。中心受光部５１からは、
微小物体の有無にかがわらずパルス変調光が得られるの
で、これをゲート信号として用いる。仮に、微小物体が
存在し、この遮光物により生ずる回折光を周ｉ７］受光
部５２が受光した時、ゲート回路１４で同期検出される
。そして、積分回路１５で積分値とした後、再び波形整
形回路１６で波形整形し、光量が一定レベルを越えた場
合に、波形整形回路１６が検出物体有りの信号を出力す
る。つまり、中心受光部５１は微小物体検出に直接寄与
しないが、中心受光部５１の出力をゲート出力として使
用し、回折光を受光する周辺受光部５２の受光出力を同
期検出することにより、微小物体による回折光線が微弱
であっても確実に検出できるようになっている。The light projector is equipped with an oscillator 11, and the light emitting diode 1 projects pulse modulated light. This makes it possible to prevent adverse effects caused by ambient light. This pulse modulated light is transmitted to the light receiving element (
When the central light receiving section 51 and the peripheral light receiving section 52) 5 receive light, the amplifier circuit 12.12a amplifies the pulse modulated light. This amplifier circuit 12.12a is AC-coupled and is set so as not to amplify stationary disturbance light but only pulse modulated light. The waveform shaping circuit 13.13a shapes the waveform of the amplified pulse modulated light. From the center light receiving section 51,
Since pulse modulated light can be obtained regardless of the presence or absence of a minute object, this is used as a gate signal. If a minute object exists and the light receiving section 52 receives the diffracted light generated by this light blocking object, the gate circuit 14 will synchronously detect the diffracted light. After the integrated value is obtained by the integrating circuit 15, the waveform is again shaped by the waveform shaping circuit 16, and when the amount of light exceeds a certain level, the waveform shaping circuit 16 outputs a signal indicating that a detected object is present. In other words, although the central light receiving section 51 does not directly contribute to the detection of minute objects, by using the output of the central light receiving section 51 as a gate output and synchronously detecting the light receiving output of the peripheral light receiving section 52 that receives diffracted light, it is possible to detect minute objects. Even if the diffracted light beam is weak, it can be reliably detected.
第７図は、透過形光電スイッチの他の実施例を示す光学
系の概略説明図である。FIG. 7 is a schematic explanatory diagram of an optical system showing another embodiment of a transmission type photoelectric switch.
この実施例では、投光レンズ２及び受光レンズ４の曲面
形状をトーリック面或いはシリフドリカル面と、回転対
称面の組合わせレンズとして、扇状に拡がるスリット光
３を射出するようにしている。また、受光素子５は第８
図で示すように、受光面の中心部に帯状（直線状）の中
心受光部５１と、その両側に配置され互いに電気的に結
合された周辺受光部５２．５２を設けた例を示している
。In this embodiment, the curved surfaces of the light emitting lens 2 and the light receiving lens 4 are a combination lens of a toric surface or a sylphdrical surface and a rotationally symmetrical surface, so that a slit light 3 that spreads out in a fan shape is emitted. Further, the light receiving element 5 is the eighth
As shown in the figure, an example is shown in which a strip-shaped (linear) central light receiving section 51 is provided at the center of the light receiving surface, and peripheral light receiving sections 52 and 52 are arranged on both sides of the central light receiving section 51 and electrically coupled to each other. .
つまり、二つの周辺受光部５２の出力線は１本に設定し
である。この場合、より微小な物体を安定して検出する
ことが出来、また受光系の上下方向の光軸合わせが極め
て簡易となる。In other words, the output lines of the two peripheral light receiving sections 52 are set to one. In this case, smaller objects can be detected stably, and vertical alignment of the optical axis of the light receiving system becomes extremely simple.
尚、投光ビーム３の形状は、実施例に限らず必要とする
検出領域の形状に応じて設定することが可能である。Note that the shape of the projected beam 3 is not limited to the embodiment and can be set depending on the shape of the required detection area.
第９図（Ａ）は、受光レンズ４に対しピンホール６１を
ｆ＃えた光軸合わせ用遮蔽板６を、脱着可能に取付けた
状態を示す説明図であり、第９図（Ｃ）は受光レンズ４
に対し光軸合わせ用レンズ６２を、脱着可能に取付けた
状態を示す説明図である。FIG. 9(A) is an explanatory diagram showing a state in which the optical axis alignment shielding plate 6 with a pinhole 61 is removably attached to the light receiving lens 4, and FIG. lens 4
FIG. 6 is an explanatory diagram showing a state in which an optical axis alignment lens 62 is removably attached to the lens.
非回折光のエネルギを中心受光部５１のみに集中させる
ためには、受光器の方向を変える等の手段により投光ビ
ーム３と受光器の光軸を合致させる必要がある。第９図
（Ａ）及び第９図（Ｃ）は、この光軸合わせ作業を容易
にするための実施例である。付加したピンホール６１及
びレンズ６２は、非回折光のスポットを大きくする作用
がある。従って、仮に光軸が僅か傾いている場合であっ
ても、中心受光部５１からの出力が得られる。そこで、
光軸調整時は、中心受光部５１からの出力が最大となる
ように受光器を調整する〔９図（Ｂ）参！！別。In order to concentrate the energy of the undiffracted light only on the central light receiving section 51, it is necessary to align the optical axes of the projected light beam 3 and the light receiver by means such as changing the direction of the light receiver. FIG. 9(A) and FIG. 9(C) are examples for facilitating this optical axis alignment work. The added pinhole 61 and lens 62 have the effect of enlarging the spot of undiffracted light. Therefore, even if the optical axis is slightly tilted, an output from the central light receiving section 51 can be obtained. Therefore,
When adjusting the optical axis, adjust the light receiver so that the output from the center light receiving section 51 is maximized [see Figure 9 (B)! ! another.
これにより、光軸調整を簡易に実行し得る。調整が終了
した特恵て、ビンボール６１或いはレンズ６２を取り外
す。尚、光軸調整は受光器の方向を変えるだけでなく、
受光レンズ４または受光素子５を光軸と垂直方向へ動か
すことによっても行い得る。Thereby, optical axis adjustment can be performed easily. After the adjustment is completed, the bottle ball 61 or lens 62 is removed. Note that optical axis adjustment not only changes the direction of the receiver;
This can also be done by moving the light receiving lens 4 or the light receiving element 5 in a direction perpendicular to the optical axis.
第６図（Ａ）乃至第６図（Ｃ）は、実施例透過形光電ス
イッチの動作原理を示す説明図である。FIG. 6(A) to FIG. 6(C) are explanatory diagrams showing the operating principle of the transmissive photoelectric switch according to the embodiment.
第６図（Ａ）は、投光ビーム３上に障害物が全く存在し
ない場合の受光面上の光強度分布を示している。この場
合、受光面の中央部に対応する位置、つまり受光レンズ
４の焦点面に対応する中心受光部５１に、光分布が集中
することとなる。仮に、球面収差のない受光レンズ４を
用いると、ｄ＝２．２μｍとなり、直径２０μｍの範囲
に受光レンズ４に入射した光の全エヱルギ含まれること
となる。第２図の実施例の構成の場合、この全エネルギ
は約２００ μＷとなる。従って、第１図に示すように
中心受光部５１の大きさを２０μｍとし、受光系の光軸
を正確に合致させておくと、障害物が存在しない場合、
周辺受光部５２の出力は発生せず、検出信号は出ない。FIG. 6(A) shows the light intensity distribution on the light receiving surface when there are no obstacles on the projected light beam 3. In this case, the light distribution will be concentrated at a position corresponding to the center of the light-receiving surface, that is, at the central light-receiving section 51 corresponding to the focal plane of the light-receiving lens 4. If the light-receiving lens 4 without spherical aberration is used, d=2.2 μm, and the total energy of the light incident on the light-receiving lens 4 will be contained within a diameter of 20 μm. For the embodiment configuration of FIG. 2, this total energy is approximately 200 μW. Therefore, as shown in FIG. 1, if the size of the central light-receiving section 51 is 20 μm and the optical axes of the light-receiving system are aligned accurately, when there are no obstacles,
No output is generated from the peripheral light receiving section 52, and no detection signal is output.
つまり、中心受光部５１からのゲート信号のみが出力さ
れることとなる。In other words, only the gate signal from the central light receiving section 51 is output.
第６図（Ｂ）は、投光ビーム３上に微小な遮光物体が存
在する場合の受光面上の光強度分布を示している。この
場合、受光面上の光強度分布は、回折効果によって大き
く変化する。つまり、受光面の中央部にメインピークが
あり、このメインピークの形状と大きさは第６図（Ａ）
と同様であるが、メインピークの両側（周辺）にやや強
度の強い光分布、つまり回折光が発生する。−例として
、直径０．２ ａｍの球状の検出物体が投光ビーム３を
部分的に遮光している場合、周辺受光部５２．）：に前
述の全エネルギの約０．０３％、つまり約６０μＷの光
パワーが分布する結果、周辺受光部５２の出力が発生し
検出信号を出す。この時、中心受光部５１からもゲート
信号が出力されており、同期検出される。FIG. 6(B) shows the light intensity distribution on the light receiving surface when a minute light blocking object exists on the projected light beam 3. In this case, the light intensity distribution on the light receiving surface changes greatly due to the diffraction effect. In other words, there is a main peak at the center of the light-receiving surface, and the shape and size of this main peak are shown in Figure 6 (A).
However, a slightly stronger light distribution, that is, diffracted light, is generated on both sides (around the main peak) of the main peak. - For example, if a spherical detection object with a diameter of 0.2 am partially blocks the projected light beam 3, the peripheral light receiving section 52. ): As a result of the distribution of optical power of about 0.03% of the above-mentioned total energy, that is, about 60 μW, an output from the peripheral light receiving section 52 is generated and a detection signal is generated. At this time, a gate signal is also output from the center light receiving section 51, and synchronous detection is performed.
第６図（Ｃ）は、受光レンズ４から離れた位置に微小な
遮光物体が存在する場合の受光面上の光強度分布を示し
ている。この場合も、第４図（Ｂ）と同様に非回折光が
中心受光部５１に、回折光が周辺受光部５２に分布する
。従って、中心受光部５１からゲート信号が出力され、
周辺受光部５２の受光信号が同期検出される。FIG. 6(C) shows the light intensity distribution on the light-receiving surface when a minute light-blocking object exists at a position away from the light-receiving lens 4. In this case as well, the undiffracted light is distributed in the central light receiving section 51 and the diffracted light is distributed in the peripheral light receiving section 52 as in FIG. 4(B). Therefore, a gate signal is output from the central light receiving section 51,
The light reception signal of the peripheral light receiving section 52 is synchronously detected.
また、この実施例における光電スイッチの検出領域は、
検出物体の大きさによって異なるが、およそ第４図のハ
ツチングで示す領域となり、小さいレンズ口径にもかか
わらず、広い視野と深い焦点深度を有する。例えば、第
５図は従来の面光源とＣＣＤラインセンサを用いた広視
野光電スイッチの配置と検出領域を示すが、この従来例
と比較すると、第４図に示す実施例では光源が小型で、
消費電力も少なく、且つ広い検出領域の得られることが
判る。In addition, the detection area of the photoelectric switch in this example is
Although it varies depending on the size of the object to be detected, the area is approximately the area shown by the hatching in FIG. 4, and has a wide field of view and a deep depth of focus despite the small lens aperture. For example, FIG. 5 shows the arrangement and detection area of a conventional wide-field photoelectric switch using a surface light source and a CCD line sensor, but compared to this conventional example, the light source is smaller in the embodiment shown in FIG.
It can be seen that power consumption is low and a wide detection area can be obtained.
（へ）発明の効果
この発明では、以上のように、点光源に近い投光素子が
投射する光を投光レンズにより広視野光線とし、この広
視野光線を結像レンズを介して受光素子で受光すると共
に、受光素子は中心受光部と周辺受光部とから構成する
こととしたから、中心受光部で非回折光を受光し、周辺
受光部で回折光を受光し、中心受光部の出力をゲート出
力として周辺受光部の受光部を同期検出する。従って、
微小物体による回折光量が微弱であっても確実に検出し
得る。(f) Effects of the Invention As described above, in this invention, the light projected by the light projecting element near the point light source is converted into a wide field of view light by the light projecting lens, and this wide field of view light is transmitted to the light receiving element via the imaging lens. In addition to receiving light, the light-receiving element is composed of a center light-receiving section and a peripheral light-receiving section, so the center light-receiving section receives undiffracted light, the peripheral light-receiving section receives diffracted light, and the output of the center light-receiving section is The light receiving section of the peripheral light receiving section is synchronously detected as a gate output. Therefore,
Even if the amount of light diffracted by a minute object is weak, it can be reliably detected.
また、この発明では投光素子を点光源とし、受光素子も
ＰＤを使用するから、光源が小型で消費電力が少なく、
且つ広い視野を確保し得る。また、検出物体が光線のど
の部分に存在しても検出することが出来、焦点深度が深
い。更に、受光回路が簡単で応答速度も速い。また、検
出物体が小さい程安定して検出し得る等、発明目的を達
成した優れた効果を有する。In addition, in this invention, the light projecting element is a point light source, and the light receiving element also uses a PD, so the light source is small and consumes little power.
Moreover, a wide field of view can be ensured. Furthermore, the detection object can be detected no matter where it is located in the light beam, and the depth of focus is deep. Furthermore, the light receiving circuit is simple and the response speed is fast. Further, the present invention has an excellent effect of achieving the object of the invention, such as the smaller the detection object, the more stable the detection.
第１図は、受光面内に中心受光部と周辺受光部を備えた
受光素子を示す説明図、第２図は、実施例透過形光電ス
イッチの基本光学系を示す説明図、第３図は、実施例透
過形光電スイッチの回路構成例を示すブロック図、第４
図は実施例光電スイッチの検出領域を示す説明図、第５
図は、従来の光電スイッチの検出領域を示す説明図、第
６図（Ａ）、第６図（Ｂ）及び第６図（Ｃ）は、受光面
上の光量分布を示す説明図であって、第６図（Ａ）は、
投光領域内に遮光物がない状態の光強度分布を示す説明
図、第６図（Ｂ）は、投光ビーム上に微小な遮光物が存
在する場合の光強度分布を示す説明図、第６図（Ｃ）は
、受光レンズから遠く離れた位置に遮光物が存在する場
合の光強度分布をしめず説明図、第７図は、光電スイッ
チの他の構成例を示す斜視図、第８図は、受光素子の他
の実施例を示す説明図、第９図（Ａ）は、受光レンズに
光軸合わせ用ピンホールを取付けた状態を示す説明図、
第９図（Ｂ）は光軸を合Ｉｋさせた状態を示す説明図、
第９図（Ｃ）は、受光レンズに光軸合わせ用レンズを取
付けた状態を示す説明図である。
ｌ二枚光素子、 ２：投光レンズ、３：投光ビー
ム、 ４：受光レンズ、５：受光素子、 ５１
：中心受光部、５２：周辺受光部。
特許出願人 立石電機株式会社代理人
弁理士 中 村 茂 信第１図
第８図
第２図
１：投也素子
２°投化レン又゛
３ニオ少也ヒ゛−ム
４：受也しン又
５：受也木子
第４図
第５図
猷（憾
第７図
第９図（Ａ）
第９図（Ｂ）Fig. 1 is an explanatory diagram showing a light receiving element having a central light receiving part and a peripheral light receiving part in the light receiving surface, Fig. 2 is an explanatory diagram showing the basic optical system of the transmission type photoelectric switch according to the embodiment, and Fig. 3 is an explanatory diagram showing the basic optical system of the transmissive photoelectric switch. , Block diagram showing an example of the circuit configuration of the transmissive photoelectric switch according to the embodiment, No. 4
The figure is an explanatory diagram showing the detection area of the example photoelectric switch.
The figure is an explanatory diagram showing the detection area of a conventional photoelectric switch, and FIG. 6(A), FIG. 6(B), and FIG. 6(C) are explanatory diagrams showing the light amount distribution on the light receiving surface. , FIG. 6(A) is
FIG. 6(B) is an explanatory diagram showing the light intensity distribution when there is no light shielding object in the light projection area, and FIG. 6(C) is an explanatory diagram that does not show the light intensity distribution when a light shielding object exists at a position far away from the light receiving lens, FIG. 7 is a perspective view showing another example of the configuration of the photoelectric switch, and FIG. The figure is an explanatory diagram showing another example of the light receiving element, FIG. 9(A) is an explanatory diagram showing a state in which a pinhole for optical axis alignment is attached to the light receiving lens,
FIG. 9(B) is an explanatory diagram showing a state in which the optical axes are aligned,
FIG. 9(C) is an explanatory diagram showing a state in which the optical axis alignment lens is attached to the light receiving lens. l Two-piece optical element, 2: Light projecting lens, 3: Light projecting beam, 4: Light receiving lens, 5: Light receiving element, 51
: center light receiving section, 52: peripheral light receiving section. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 1 Figure 8 Figure 2 1: Throwing Element 2° Throwing Lens Mata 3 Nio Shaya Hime 4: Ukeya Shinmata 5: Ukeya Kimiko Figure 4 5 Figure 9 (A) Figure 9 (B)
Claims (2)
を広視野光線にする投光レンズと、広視野光線を結像レ
ンズを介して受光する受光素子とからなり、前記受光素
子の受光面は非回折光を受光する中心受光部と、回折光
を受光する周辺受光部とから構成し、中心受光部の出力
をゲート信号として周辺受光部の受光量を同期検出する
ことで、検出物体の有無を判別し検出信号を出力する透
過形光電スイッチ。(1) Consisting of a light projecting element close to a point light source, a light projecting lens that converts the light projected by the light projecting element into a wide field of view light, and a light receiving element that receives the wide field of view light through an imaging lens, The light-receiving surface of the element consists of a central light-receiving section that receives non-diffracted light and a peripheral light-receiving section that receives diffracted light. , a transmission type photoelectric switch that determines the presence or absence of a detection object and outputs a detection signal.
能に取付けたものである特許請求の範囲第１項記載の透
過形光電スイッチ。(2) The transmission type photoelectric switch according to claim 1, wherein an optical axis adjustment lens is detachably attached to the imaging lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33565387A JPH01175138A (en) | 1987-12-28 | 1987-12-28 | Permeation type photoelectric switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33565387A JPH01175138A (en) | 1987-12-28 | 1987-12-28 | Permeation type photoelectric switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01175138A true JPH01175138A (en) | 1989-07-11 |
Family
ID=18291009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33565387A Pending JPH01175138A (en) | 1987-12-28 | 1987-12-28 | Permeation type photoelectric switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01175138A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62284521A (en) * | 1986-06-02 | 1987-12-10 | Omron Tateisi Electronics Co | Photoelectric switch |
-
1987
- 1987-12-28 JP JP33565387A patent/JPH01175138A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62284521A (en) * | 1986-06-02 | 1987-12-10 | Omron Tateisi Electronics Co | Photoelectric switch |
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