JPH03137590A - Photoelectric switch - Google Patents
Photoelectric switchInfo
- Publication number
- JPH03137590A JPH03137590A JP1276396A JP27639689A JPH03137590A JP H03137590 A JPH03137590 A JP H03137590A JP 1276396 A JP1276396 A JP 1276396A JP 27639689 A JP27639689 A JP 27639689A JP H03137590 A JPH03137590 A JP H03137590A
- Authority
- JP
- Japan
- Prior art keywords
- light
- detected
- light receiving
- incident
- photoelectric switch
- 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
- 230000010287 polarization Effects 0.000 claims abstract description 8
- 238000001514 detection method Methods 0.000 abstract description 11
- 238000009792 diffusion process Methods 0.000 abstract description 9
- 239000013307 optical fiber Substances 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract 1
- 238000002834 transmittance Methods 0.000 description 14
- 239000004698 Polyethylene Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- -1 polyethylene Polymers 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 239000004677 Nylon Substances 0.000 description 2
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は透明又は半透明であって、その存在の有無によ
る光の透過率の変化が極めて小さい検出対象物を適確に
検出できる透過型の光電スイッチに関する。Detailed Description of the Invention [Field of Industrial Application] The present invention is a transmissive type that can accurately detect a detection target that is transparent or semitransparent and whose light transmittance changes extremely little depending on its presence or absence. related to photoelectric switches.
物品の有無を光の透過率又は反射率の変化により検出し
、電気信号として出力する光電スイッチは、広範な用途
に用いられる。この光電スイッチの透過型のものを第５
図に示すと、（１）は投光部で、図示しないアンプユニ
ット内の発光素子から光を導く光ファイバ（２）と、こ
の光ファイバ（２）から出た光を可及的に平行光化する
レンズ（３）を有する。（４）は投光部（１）に対向配
置された受光部で、アンプユニット内の受光素子に光結
合された光ファイバ（５）の端部前方に集光レンズ（６
）を配置している。2. Description of the Related Art Photoelectric switches that detect the presence or absence of an article based on a change in light transmittance or reflectance and output it as an electrical signal are used in a wide range of applications. The transmission type of this photoelectric switch is the fifth one.
As shown in the figure, (1) is a light projector, which includes an optical fiber (2) that guides light from a light emitting element in an amplifier unit (not shown), and a parallel light beam that converts the light emitted from this optical fiber (2) into as much parallel light as possible. It has a lens (3) that changes. (4) is a light receiving unit disposed opposite to the light projecting unit (1), and is located in front of the end of the optical fiber (5) that is optically coupled to the light receiving element in the amplifier unit.
) are placed.
この光電スイッチ（７）は、投光部（１）から受光部（
４）に向かう光を検出対象物（８）が遮り、受光レベル
が所定値以下になると、物品有りの判定をし、電気信号
として出力する。This photoelectric switch (7) has a light emitter (1) to a light receiver (
When the detection object (8) blocks the light directed toward 4) and the received light level falls below a predetermined value, it is determined that an article is present and output as an electrical signal.
上記透過型の光電スイッチ（７）は、光の透過率の変化
により物品の有無を検出するので、不透明な検出対象物
に対しては、正確な検出が行える。The transmission type photoelectric switch (7) detects the presence or absence of an object based on a change in light transmittance, so that it can accurately detect an opaque object to be detected.
しかし、検出対象物が、ポリエチレン、ナイロン、塩化
ビニールのフィルム等のように透明又は半透明の物であ
ると、その有無による透過率の変化は数％程度であるた
め、アンプユニット内の判定レベルの設定が掻めて困難
になる。However, if the object to be detected is transparent or translucent, such as polyethylene, nylon, or vinyl chloride film, the change in transmittance due to the presence or absence of the object is only a few percent, so the judgment level within the amplifier unit is It becomes difficult to set the settings.
そして、電源電圧の変動、投光部及び受光部の投受光面
の汚れ、被検出物の透過率の微小なばらつき等によって
誤動作し易い。Malfunctions are likely to occur due to fluctuations in power supply voltage, dirt on the light emitting/receiving surfaces of the light emitting section and the light receiving section, minute variations in the transmittance of the object to be detected, and the like.
なお、このような透明又は半透明の検出対象物を、反射
型の光電スイッチを用いて検出しようとしても、やはり
誤動作し易く実用性に乏しい、透明又は半透明の物体は
、入射した光の大部分を透過するため、反射率が本来少
なく、さらにフィルム状のものでは、風圧等で揺れ動き
反射方向が大きく変化するからである。Note that even if you try to detect such a transparent or semi-transparent object using a reflective photoelectric switch, it is likely to malfunction and is impractical. This is because the reflectance is inherently low because the light passes through a portion of the light, and in the case of a film-like film, it sways due to wind pressure and the like, and the direction of reflection changes greatly.
そこで本発明は、透明又は半透明の検出対象物の存在の
有無を信頼性高く判定できる光電スイッチを提供するこ
とを目的とする。SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a photoelectric switch that can reliably determine the presence or absence of a transparent or translucent detection target.
本発明は透明又は半透明の物体の多くが、光を拡散しつ
つ透過させる光拡散透過性を有していることに着目し、
この拡散光のみを一対の偏光板を用いることにより検出
しようとするものである。The present invention focuses on the fact that many transparent or semi-transparent objects have a light diffusion transmittance that allows light to pass through while being diffused.
The aim is to detect only this diffused light by using a pair of polarizing plates.
したがうて、本発明は、ポリエチレン、ナイロン、塩化
ビニールのフィルム等の表面又は内部に光を拡散させる
粗面又は不均一層がある透明または半透明の物体の検出
に適し、鏡面仕上げされたガラス板のような光の拡散が
少ない物体の検出には適さない。Therefore, the present invention is suitable for detecting transparent or translucent objects that have a rough surface or uneven layer that diffuses light on the surface or inside, such as polyethylene, nylon, or vinyl chloride films, and is suitable for detecting mirror-finished glass plates. It is not suitable for detecting objects with low light diffusion such as objects.
そして、このような光拡散透過性の物体の有無判定に用
いられる本発明の光電スイッチは、検出対象物を挾んで
投光部及び受光部を対向配置し、この投光部の投光面及
び受光部の受光面に、夫々偏光方向が相互に９０”異な
る偏光板を配置し、投光部から受光部に入射し、受光部
の偏光板を透過した光量が所定レベルを越えたとき、検
出対象物有りの判定して電気的に出方する構成を育する
。The photoelectric switch of the present invention, which is used to determine the presence or absence of such a light-diffusion-transmitting object, has a light emitting section and a light receiving section facing each other with the object to be detected sandwiched between them. Polarizing plates are placed on the light-receiving surface of the light-receiving section, and when the amount of light that enters the light-receiving section from the light-emitting section and passes through the polarizing plate of the light-receiving section exceeds a predetermined level, it is detected. Develop a configuration that determines the presence of an object and outputs it electrically.
上記構成において、投光部がら投光される光は、その偏
光板の作用によって偏光となる。この偏光は検出対象物
が存在しない場合は、この偏光方向を変化させないで、
受光部に入射する、しかし受光部の偏光板は、これとは
偏光方向が９０°異なっているので、この偏光を完全に
遮断し、受光素子への入射光はない。In the above configuration, the light projected from the light projecting section becomes polarized light by the action of the polarizing plate. If there is no object to be detected, this polarized light does not change its polarization direction.
However, since the polarizing plate of the light receiving part has a polarization direction that is 90° different from this, this polarized light is completely blocked, and no light enters the light receiving element.
一方拡散透過性を持つ検出対象物がある場合は、投光部
から投光された偏光は、検出対象物を透過する際に、光
束の微小な単位毎に、その投光方向を不規則に変化させ
る。このため受光部の偏光板と偏光方向が一致して透過
する光の成分が拡散の程度に応じて発生し、これが受光
素子に入射して、受光出力を発生させる。On the other hand, if there is an object to be detected that has diffuse transmittance, the polarized light emitted from the light emitter will change the direction of the light irregularly for each minute unit of light flux as it passes through the object. change. Therefore, a component of light that is transmitted with the same polarization direction as that of the polarizing plate of the light receiving section is generated depending on the degree of diffusion, which enters the light receiving element and generates a light receiving output.
したがって、アンプユニットの判定回路は、この受光素
子の受光出力が零若しくは所定レベルに満たないとき、
物品なしと判定し、この受光出力が所定レベル以上のと
き物品ありと判定し、電気的に判定信号を出力する。Therefore, the determination circuit of the amplifier unit determines that when the light receiving output of this light receiving element is zero or less than a predetermined level,
It is determined that there is no article, and when this light reception output is equal to or higher than a predetermined level, it is determined that there is an article, and an electrical determination signal is output.
特に、本発明は、検出対象物が存在しないときは、投光
量をいかに多くしても受光出力が零であるので、光透過
率が小さい検出対象物であっても、投光量を多くするこ
とにより検出可能とすることができる。In particular, in the present invention, when there is no object to be detected, the received light output is zero no matter how much light is emitted, so even if the object is to be detected with low light transmittance, the amount of light emitted can be increased It can be made detectable by
本発明の一実施例を図面を参照して以下に説明する。 An embodiment of the present invention will be described below with reference to the drawings.
第１図に示す光電スイッチ（１０）の構成図において、
（１１）は投光部で、図示しないアンプユニットの発光
素子から延長された光ファイバ（１２）の端部前方に、
集光レンズ（１３）を配置し、さらにその前面に偏光板
（１４）を配置している。 （１５）は前記投光部（
１１）と対向配置した受光部で、前記アンプユニットの
受光素子と光結合された光ファイバ（１６）の端部前方
に、集光レンズ（１７）を配置し、さらにその前面に偏
光板（１８）を配置している。 （１９）は投光部（
１１）と受光部（１５）の間に通される検出対象物で、
ポリエチレンフィルム等の光拡散透過性を有するもので
ある。In the configuration diagram of the photoelectric switch (10) shown in FIG.
(11) is a light projecting part, which is located in front of the end of an optical fiber (12) extending from a light emitting element of an amplifier unit (not shown).
A condensing lens (13) is arranged, and a polarizing plate (14) is further arranged in front of it. (15) The light projecting section (
11), a condensing lens (17) is disposed in front of the end of the optical fiber (16) that is optically coupled to the light receiving element of the amplifier unit, and a polarizing plate (18) is disposed in front of the condensing lens (17). ) are placed. (19) is the light emitting part (
11) and a detection target passed between the light receiving part (15),
It is a material that has light diffusion and transparency, such as a polyethylene film.
上記構成において、２つの偏光板（１４） （１８）
は、図示したように、その偏光方向が相互に９０°異な
っている。In the above configuration, two polarizing plates (14) (18)
As shown in the figure, their polarization directions differ by 90° from each other.
また、投光部（１１）の集光レンズ（１３）は、偏光板
（１４）に向かう光を可及的に平行光化するためのもの
で、偏光を得るため必要である。Further, the condensing lens (13) of the light projection unit (11) is for collimating the light directed toward the polarizing plate (14) as much as possible, and is necessary to obtain polarized light.
また受光部（１５）の集光レンズ（１７）は偏光板（１
８）を透過した光を、光ファイバ（１６）に集光するた
めに用いられる。In addition, the condenser lens (17) of the light receiving section (15) is equipped with a polarizing plate (1
8) is used to condense the light transmitted through the optical fiber (16).
上記構成において、投光部（１１）から受光部（１５）
に向けて投光された偏光りは、拡散透過性を有する検出
対象物（１９）に入射すると、その表面が、完全な鏡面
でない、或いは、その内部が光学的に均一でない等の原
因によって拡散しながら透過する。このため受光部（１
５）の偏光板（１８）には、拡散の程度に応じて偏光性
を持つ光として入射し、受光部（１５）の偏光板（１８
）の偏光方向に一致した光が、集光レンズ（１７）及び
光ファイバ（１６）を通して、図示しない受光素子に入
射する。In the above configuration, from the light emitter (11) to the light receiver (15)
When the polarized light projected toward the target object (19) enters the detection object (19), which has diffuse transmittance, it becomes diffused due to reasons such as the surface of the object is not a perfect mirror or the inside thereof is not optically uniform. Transparent while doing so. Therefore, the light receiving part (1
The light enters the polarizing plate (18) of the light receiving part (15) as polarized light depending on the degree of diffusion.
) is incident on a light receiving element (not shown) through a condenser lens (17) and an optical fiber (16).
この受光素子の出力はアンプユニット内の判定回路で所
定の基準電圧と比較され、検出対象物ありと判定される
。The output of this light receiving element is compared with a predetermined reference voltage in a determination circuit within the amplifier unit, and it is determined that there is an object to be detected.
一方、第２図に示すように検出対象物がない場合は、投
光部（１１）から投光された偏光りは、偏光性を保った
まま、受光部（１５）の偏光板（１８）に入射するため
、ここで遮光され、受光素子の出力は無信号レベルとな
る。したがって、アンプユニット内の判定回路で、検出
対象物なしの判定がされる。On the other hand, when there is no object to be detected as shown in FIG. Since the light is incident on the light source, the light is blocked here, and the output of the light receiving element becomes a no-signal level. Therefore, the determination circuit within the amplifier unit determines that there is no object to be detected.
ここで、本発明の光電スイッチ（１０）が拡散透過性を
持つ検出対象物に対して、いかに信頼性高く判定を行う
かについて数値例を示して説明する。Here, a numerical example will be given to explain how the photoelectric switch (10) of the present invention makes a highly reliable determination for a detection target having diffuse transmittance.
検出対象物の光の透過率が９７％、拡散率（入射した偏
光の全光量に対し、さらに９０’偏光した光の光量の比
率）を３％とすると、受光部の受光レベル（受光素子の
増幅器を通した出力電圧）は、第５図に示す偏光板がな
い光電スイッチ（７）の場合は、検出対象物（８）が無
しから有りに変化しても、受光出力が１００％から９７
％、例えばＩＯＶから９．７Ｖと小さい比率でしか変化
しない、一方、第１図に示す本発明の偏光板を有する光
電スイッチ（１０）の場合は、検出対象物（１９）が無
しから有りに変化すると、例えばＯＶから０．２９Ｖと
変化する。Assuming that the light transmittance of the object to be detected is 97% and the diffusion rate (ratio of the amount of 90' polarized light to the total amount of incident polarized light) is 3%, the light receiving level of the light receiving part (the light receiving level of the light receiving element) is 3%. In the case of the photoelectric switch (7) without a polarizing plate shown in Fig. 5, the output voltage (output voltage through an amplifier) will vary from 100% to 97% even if the detection target (8) changes from absent to present.
%, for example, 9.7V from IOV.On the other hand, in the case of the photoelectric switch (10) having the polarizing plate of the present invention shown in FIG. 1, the detection target (19) changes from absent to present. When the voltage changes, for example, it changes from OV to 0.29V.
つまり、本発明の光電スイッチは拡散光の有無によって
０％から１００％へと受光出力が変化するので、電源電
圧の低下、投受光面の汚れ等に殆ど影響されないで判定
できる。In other words, in the photoelectric switch of the present invention, the light receiving output changes from 0% to 100% depending on the presence or absence of diffused light, so that determination can be made almost unaffected by a drop in power supply voltage, dirt on the light emitting/receiving surface, etc.
このように本発明の光電スイッチ（１０）が、光の透過
率の変化を検出するのではなく、拡散の有無を検出して
いることは、第３図に示すように、光透過率が小さい絵
柄（２０）が点在するフィルム（２１）等の検出にも使
用できることになる。すなわち、絵柄（２０）の部分で
も、十分に光が透過するような強い光で投光すれば、こ
の透過した光の拡散の有無を検出できるのである。一方
、第５図に示す従来の光電スイッチ（７）では、絵柄の
有る場所とない場所で光の透過率が大きく異なるため検
出できない。The fact that the photoelectric switch (10) of the present invention detects the presence or absence of diffusion rather than a change in the light transmittance is because the light transmittance is small, as shown in FIG. It can also be used to detect a film (21) etc. in which patterns (20) are scattered. That is, if light is projected with enough intensity to pass through the pattern (20), it is possible to detect whether or not the transmitted light is diffused. On the other hand, with the conventional photoelectric switch (7) shown in FIG. 5, the light transmittance differs greatly between areas with and without patterns, and therefore cannot be detected.
本発明は、必ずしも第１図に示したように、投光部（１
１）と受光部（１５）を分離する必要はない、検出対象
物の厚みを、所定範囲内に決められる場合は、第４図に
示すように一体型とする方が、取付けが容易になる。The present invention does not necessarily include the light projecting section (1) as shown in FIG.
1) and the light receiving part (15) do not need to be separated; if the thickness of the object to be detected can be determined within a predetermined range, installation will be easier if they are integrated as shown in Figure 4. .
第４図は馬蹄形の本体ケースに組み込んだ実施例で、検
出対象物（１９）を通す検出用スリン） （２２）を挾
むように投光部（１１）と受光部（１５）を配置し、本
体ケースの基部に投光部（１１）のドライバ回路を含む
制御回路（２３）、受光部（１５）のアンプ（２４）
、判定回路（２５）等を組み込んでいる。なお、この実
施例では光ファイバを使用せず、投光素子（２６）及び
受光素子（２７）を直接に集光レンズ（１４） （１
８）に対向させている。Fig. 4 shows an example in which the main body is assembled into a horseshoe-shaped main case, in which the light emitting part (11) and the light receiving part (15) are arranged so as to sandwich the detection ring (22) through which the object to be detected (19) passes. A control circuit (23) including a driver circuit for the light emitter (11) and an amplifier (24) for the light receiver (15) are installed at the base of the case.
, a determination circuit (25), etc. are incorporated. In addition, in this embodiment, an optical fiber is not used, and the light emitting element (26) and the light receiving element (27) are directly connected to the condensing lens (14) (1
8).
本発明は、一対の偏光板を用いることにより、物体の有
無を透過光量の変化ではなく拡散光量の有無のみに着目
して検出する。このため、透明または半透明の物体であ
っても、信頌性高く確実に検出できる。By using a pair of polarizing plates, the present invention detects the presence or absence of an object by focusing only on the presence or absence of the amount of diffused light, rather than the change in the amount of transmitted light. Therefore, even transparent or semi-transparent objects can be detected reliably and with high reliability.
第１図及び第２図は本発明の光電スイッチの構成を示し
、第１図は検出対象物が有る場合、第２図は検出対象物
が無い場合を夫々示す。
第３図は、本発明の光電スイッチで検出可能となった絵
柄付きフィルムの平面図、第４図は本発明の他の実施例
を示す概略構成図である。
第５図は従来の光電スイッチの構成図である。
（ｌＯ）−光電スイッチ、（１１）−・投光部、（１４
） （１８）−ｍ−偏光板、（１５）−・−受光部、
（１９）−検出対象物。
特 許出願人 北陽電機株式会社
代 理 人 江 原 省
吾第１図
第２図1 and 2 show the configuration of the photoelectric switch of the present invention, FIG. 1 shows the case where there is an object to be detected, and FIG. 2 shows the case where there is no object to be detected, respectively. FIG. 3 is a plan view of a patterned film that can be detected by the photoelectric switch of the present invention, and FIG. 4 is a schematic diagram showing another embodiment of the present invention. FIG. 5 is a block diagram of a conventional photoelectric switch. (lO) - Photoelectric switch, (11) - Light emitter, (14
) (18)-m-polarizing plate, (15)--light receiving section,
(19) - Detection target object. Patent applicant: Hokuyo Electric Co., Ltd. Agent: Gangwon Province
Figure 1 Figure 2
Claims (1)
投光部及び受光部を対向配置し、この投光部の投光面及
び受光部の受光面に、夫々偏光方向が相互に９０°異な
る偏光板を配置し、投光部から受光部に入射した受光部
の偏光板を透過し光量が所定値を越えたとき検出対象物
有りと判定することを特徴とする光電スイッチ。A light emitting part and a light receiving part are arranged opposite to each other with a transparent or semi-transparent light-diffusion-transmissive object to be detected sandwiched between them, and the light emitting surface of the light emitting part and the light receiving surface of the light receiving part have polarization directions of 90° to each other. A photoelectric switch characterized by arranging different polarizing plates and determining that an object to be detected is present when the amount of light transmitted from the light projecting part to the light receiving part exceeds a predetermined value after passing through the polarizing plate of the light receiving part.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1276396A JPH03137590A (en) | 1989-10-23 | 1989-10-23 | Photoelectric switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1276396A JPH03137590A (en) | 1989-10-23 | 1989-10-23 | Photoelectric switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03137590A true JPH03137590A (en) | 1991-06-12 |
Family
ID=17568824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1276396A Pending JPH03137590A (en) | 1989-10-23 | 1989-10-23 | Photoelectric switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03137590A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9394196B2 (en) * | 2006-12-14 | 2016-07-19 | Ppg Industries Ohio, Inc. | Low density and high strength fiber glass for reinforcement applications |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6420479A (en) * | 1987-07-14 | 1989-01-24 | Nec Corp | Photosensor |
-
1989
- 1989-10-23 JP JP1276396A patent/JPH03137590A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6420479A (en) * | 1987-07-14 | 1989-01-24 | Nec Corp | Photosensor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9394196B2 (en) * | 2006-12-14 | 2016-07-19 | Ppg Industries Ohio, Inc. | Low density and high strength fiber glass for reinforcement applications |
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