JP2922931B2 - Fiber optic photoelectric switch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber photoelectric switch, and more particularly, to a switch that combines a light projecting element and a light receiving element to detect light blocking or reflection by an object to be detected. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber type photoelectric switch in which an optical fiber is connected to a light projecting element and a light receiving element, and a detection unit can be set at a position away from the light projecting element and the light receiving element.

[Conventional technology]

The photoelectric switch has the features that it can perform a switch operation by detecting the presence or absence of a detection target in a non-contact manner and that the switch operation is reliable, and is incorporated in a control mechanism for controlling various mechanical devices. Has been used. Especially,
Since the optical fiber type photoelectric switch can be installed at an arbitrary position and posture at the detection unit provided at the tip of the optical fiber, the detection unit can be set at a place away from the photoelectric switch body, and the installation of the detection unit It has advantages that the space may be narrow and that a plurality of photoelectric switches can be collected and managed in one place.
It has become widely used.

FIG. 9 shows an appearance structure of a general optical fiber type photoelectric switch. The photoelectric switch body 1 controls the light emitting element and the light receiving element together with the light emitting element and the light receiving element, and amplifies the detection signal. An amplifier unit composed of a control circuit is installed. An optical fiber 2 for light emission and an optical fiber 3 for light reception are connected to the photoelectric switch body 1, and a detection unit 4 is provided at the tip of both fibers 2, 3. The illustrated photoelectric switch is a reflection-type photoelectric switch, and the light projected from the tip of the detection unit 4 to the detection target space is reflected by the detection target object, and the reflected light is returned to the detection unit 4 again. Thereby, the detection target is detected and the operation is performed. In the photoelectric switch, in addition to the reflection type shown in the figure, a light-emitting detecting unit and a light-receiving detecting unit are arranged to face each other, and the photoelectric switch is operated by blocking an optical path between the light-emitting detecting units by an object to be detected. There is also a transmission type photoelectric switch.

When using an optical fiber photoelectric switch as described above, there is a case where it is desired to perform a switch operation based on a combination result of detection main forces at a plurality of detection units. For example, when the switch is to be operated only when the detection target is detected by both of the two detection units, or when the switch is to be operated when the detection target is detected by at least one of the two detection units. And so on. That is, a plurality of detection units, that is, photoelectric switches
D-connection or OR-connection. As described above, in the case where the switch operation is performed based on the result of the logical operation of the detection in the plurality of detection units, conventionally, a plurality of photoelectric switches corresponding to the number of the detection units are used side by side, and the detection output from each photoelectric switch is used. The switch is operated according to the result of the signal being logically processed by an appropriate electronic circuit.

FIG. 10 shows an example of a circuit in the case of outputting a logical operation result by combining a plurality of photoelectric switches. In FIG. 10 (a), the output transistors t of the _two photoelectric switches S ₁ and S ₂ are used. Are OR-connected on the electric circuit C to perform the switching operation of the load P, and FIG. 10 (b)
Then, the AND connection is made in the same way.

[Problems to be solved by the invention]

However, in the above-described conventional technology, the number of photoelectric switch bodies 1 equal to the number of inputs for performing logical operation, that is, the number of detectors 4 is determined.
However, there is a problem that the cost is extremely high and the installation space is additionally required. Further, an electric circuit for performing a logical operation on the output from the photoelectric switch is also required. If the AND circuit shown in Figure 10 (b), one of the circuit current of the photoelectric switch S ₁ is, since also flows to the other output transistor of the photoelectric switch S _2, it should be aware of the current capacity and voltage drop, In particular, in the case of an AND circuit, there is a problem that the photoelectric switches S ₁ and S ₂ that are electrically connected to each other are affected by each other, such as the number of photoelectric switches S _{1 that} can be connected simultaneously is limited. Furthermore, since the output from the photoelectric switches S ₁ ... Is logically operated, there is a problem that the response speed until the final switch operation is delayed by the rise time of the photoelectric switch S ₁ .

Therefore, an object of the present invention is to provide an optical fiber photoelectric switch capable of performing logical operation on detection information from a plurality of detection units and outputting the information as described above. The object of the present invention is to provide a device that operates reliably and has a high response speed.

[Means for solving the problem]

The optical fiber type photoelectric switch according to the first aspect of the present invention, which solves the above problem, has a light emitting unit, a light emitting unit, a light receiving unit and an amplifier unit, and a light emitting unit and a light receiving unit. A reflection type optical fiber type photoelectric switch including a connected optical fiber and a detection unit provided at the tip of the optical fiber, and emitting and receiving light by one detection unit, wherein one end of the optical fiber is connected to the detection unit and the other end. An optical fiber for light emission whose end is connected to the light emitting unit, and a light receiving optical fiber whose one end is connected to the detecting unit and the other end is connected to the light receiving unit, wherein the detecting unit has a plurality, Although the information can be individually detected, the information is connected to the same light emitting part and light receiving part, and a plurality of pieces of information detected by the plurality of detecting parts are logically operated. Are input to the light receiving unit of the photoelectric switch body.

An optical fiber photoelectric switch according to the present invention is a photoelectric switch body including a light emitting unit having a light emitting element, a light receiving unit having a light receiving element, an amplifier unit for controlling the light emitting element and the light receiving element and amplifying a detection signal, and the like. And, an optical fiber connected to the light emitting part and the light receiving part of the photoelectric switch body, and a detecting part provided at the tip of the optical fiber, the detecting part, the light emitting optical fiber and the light receiving optical fiber are arranged, A so-called reflection type photoelectric switch is configured in which light projected from the tip of the light emitting optical fiber is reflected by the object to be detected, and returned light is received by the tip of the light receiving optical fiber. Such a basic structure of the photoelectric switch, particularly the structure of the photoelectric switch body, can be exactly the same as that of a normal optical fiber photoelectric switch.

According to the present invention, a detection signal is logically operated by a combination structure of an optical fiber and a detecting unit, and a result of the logical operation is input to a light receiving unit of the photoelectric switch main body. In the optical fiber, a plurality of light emitting optical fibers are connected to the light projecting unit, and a plurality of light receiving optical fibers are also connected to the light receiving unit. Among them, one or a plurality of one set of light emitting optical fibers and one set of light receiving optical fibers are arranged and connected to one detecting section, and a plurality of such detecting sections are provided. That is, a plurality of sets of detecting units are connected in parallel to one set of the light projecting unit and the light receiving unit. Then, if any one of the plurality of detection units detects a detection object, a detection signal is input to the light receiving unit. Therefore, the detection signals in the plurality of detection units are referred to by a logical operation. An OR operation is performed and the result is input to the light receiving section of the photoelectric switch body.

The number of detectors to be installed can be two or three or more depending on the number of pieces of detection information required. When the number of detection units increases, the amount of light projected to each detection unit decreases. Therefore, it is preferable to increase the output of the light projection unit of the photoelectric switch body or increase the number of light projection units. When the amount of light received by the light receiving unit decreases, the sensitivity of the light receiving unit may be increased or the number of light receiving units may be increased.

The optical fiber type photoelectric switch according to claim 2 includes a photoelectric switch body having a light projecting unit, a light receiving unit, and an amplifier unit, an optical fiber connected to the light projecting unit and the light receiving unit, and a detecting unit provided at a tip of the optical fiber. A reflection-type optical fiber photoelectric switch that emits and receives light with a single detection unit, wherein the detection unit is provided in a plurality of stages, and a first-stage detection unit includes a light-emitting unit connected to the light-projection unit. And one end of another light receiving optical fiber is connected to the other end, and the other end of the light receiving optical fiber of the preceding stage detecting portion is connected to the second stage and subsequent detecting portions. And one end of another light-receiving optical fiber is connected to the other end, and the other end of the light-receiving optical fiber in the final-stage detection section is connected to the light-receiving section of the photoelectric switch body. Going on.

The basic structure is the same as that of the first aspect of the present invention, and in this case also, the structure of the detection unit constitutes a reflective photoelectric switch.

According to the present invention, the light emitting optical fiber connected to the light emitting portion of the photoelectric switch main body is first connected to the first stage detecting portion, and the light receiving optical fiber of the first stage detecting portion is connected to the light receiving portion of the photoelectric switch main body. The other end of the other receiving optical fiber is connected to both the light emitting optical fiber of the second stage detecting unit and the other end of the light receiving optical fiber of the final stage detecting unit is connected to the light receiving unit of the photoelectric switch body. It is to be connected to.

The basic structure is the same as that of the first aspect of the present invention, and in this case also, the structure of the detection unit constitutes a reflective photoelectric switch.

According to the present invention, the light emitting optical fiber connected to the light emitting portion of the photoelectric switch main body is first connected to the first stage detecting portion, and the light receiving optical fiber of the first stage detecting portion is connected to the light receiving portion of the photoelectric switch main body. , And is used as a light emitting optical fiber of the second stage detection unit. Then, the light receiving optical fiber of the final stage detecting section is connected to the light receiving section of the photoelectric switch main body. That is, a plurality of detection units are serially connected in order by optical fibers, and light emitted from the light emission unit of the photoelectric switch main body returns to the light reception unit via each detection unit. It has become. Therefore, the detection signal is not input to the light-receiving unit unless all the detection units detect the detection target, and the detection signals of the multiple-stage detection unit are AND-operated and input to the light-receiving unit of the photoelectric switch body. become.

[Action]

According to the first aspect of the present invention, as described above, in the plurality of sets of the reflection type detection units installed in parallel, the respective detection units are independently connected to the light emitting unit and the light receiving unit. If any one of the detection units detects the detection target, the detection signal is input to the light receiving unit of the photoelectric switch main body. That is, the detection signals from the plurality of detection units are ORed.

According to the second aspect of the present invention, as described above, the plurality of reflection-type detection units installed in series are connected from the light-emitting unit to the light-receiving unit in such a manner that all the detection units are connected in series. Therefore, the detection signal is not input to the light receiving unit of the photoelectric switch main body unless all the detecting units detect the detection target.
That is, the detection signals from the plurality of detection units are ANDed.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

In the embodiment shown in FIG. 1, an output obtained by ORing reflection type photoelectric switches is obtained.

The photoelectric switch body 10 has a light emitting element, a light receiving element, an amplifier unit, a power supply, and other structures similar to those of a normal photoelectric switch. At one end of the photoelectric switch main body 10, a light projecting unit 11 and a light receiving unit 12 are provided.

A light projecting optical fiber cable 20 is connected to the light projecting unit 11 via a connector 21. The light projecting optical fiber cable 20 is composed of an aggregate of a plurality of optical fibers 22. In the figure, an enlarged end view of the connector 21 is shown on the side of the connector 21. In this figure, black circles represent individual optical fibers 22. The receiver 12 has a connector
The optical fiber cable 30 for light reception is connected via 31. The light receiving optical fiber cable 30 is also formed of an aggregate of a plurality of optical fibers 32. In the enlarged view of the end face of the connector 31, the light receiving optical fiber 32 is represented by a white circle.

After the optical fiber cable 20 for light emission and the optical fiber cable 30 for light reception,
The coupler 70 near the distal end is divided into individual optical fiber cables 60 for detection and connected to the detecting section 40 at the distal end. In the detection unit 40, the light projecting optical fiber 22 and the light receiving optical fiber 32 are arranged side by side. In the figure, detector
An enlarged end view of the detection unit 40 is shown on the side of 40, and the projecting optical fiber 22 is a black circle, and the receiving optical fiber is
32 is represented by a white circle. That is, some optical fibers 22 and 32 are divided from the light emitting and receiving optical fiber cables 20 and 30, taken out to one detecting optical fiber cable 60, and connected to the detecting unit 40.

The operation of the optical fiber photoelectric switch having the above structure will be described. Arrows in the figure indicate the progress of light.

The light emitted from the light emitting unit 11 of the photoelectric switch main body 10 to the light emitting optical fiber 22 is emitted from the tip of each of the detection units 40 and 40 through another optical fiber 22. Detector 40
In front of the object, that is, the detection target M to be detected
When there is, the light is reflected, returns to the detection unit 40 again, and is received by the light receiving optical fiber 32. The light received by the optical fiber 32 for receiving light is
The electrical detection signal is output to the control unit 12 and then passed through the amplifier unit of the photoelectric switch body 10 and the like, and is input to an external control device or the like. As shown in FIG. 1, among the two detection units 40, 40, only the detection unit 40 located at the upper part in the figure detects the detection target M, and the detection part 40 located at the lower part in the figure If the object M is not detected, the lower detection unit
Although the light cannot be received by the light receiving optical fiber 32 from 40, the light received by the upper detecting unit 40 is transmitted to the light receiving unit 12 through the light receiving optical fiber 32 without any trouble. That is, in this embodiment, an OR connection is provided in which a detection signal is input to the light receiving unit 12 when at least one of the plurality of detecting units 40 detects the detection target M.

FIG. 2 shows an embodiment partially modified from the above embodiment. In this embodiment, a large number of detection units 40 are used, and two light emitting optical fiber cables 20 are used. Each projecting optical fiber cable 20 is a connector 21,
They are connected to the respective light emitting units 11,11. Therefore, the photoelectric switch main body 10 is provided with a plurality of light projecting units 11,11.

As described above, the number of detectors 40 can be arbitrarily increased as needed. When the number of detecting units 40 increases, dividing the light emitted from one light emitting unit 11 reduces the amount of light emitted by each detecting unit 40.
Is used to increase the amount of projected light. In addition, light receiving section
In order to increase the detection sensitivity in 12, the number of light receiving sections 12 may be increased to a plurality.

In the embodiment shown in FIG. 3, an AND-connected output is obtained by a reflection type photoelectric switch. The same reference numerals are given to the same structural parts as those in the above-described embodiment, and redundant description will be omitted.

The light emitting optical fiber cable 20 containing one optical fiber 22 is connected to the first-stage detection unit 40.
One end of an optical fiber cable 61 accommodating a light receiving optical fiber 62 is connected to the detection unit 40. However, this optical fiber 62 and optical fiber cable 61
Is not directly connected to the light receiving unit 12, but is connected to the detection unit 41 in the next stage. The optical fiber cable 30 containing the light receiving optical fiber 32 is connected to the detection unit 41 together with the optical fiber 62 and the optical fiber cable 61. That is, in this embodiment, two stages of the detection units 41 are provided.

The operation of the optical fiber photoelectric switch having such a structure will be described.

The light projected from the light projecting unit 11 to the light projecting optical fiber 22 and projected from the light projecting optical fiber 22 at the tip of the detecting unit 40 is reflected by the detection target M, and is again reflected by the optical fiber 62 of the detecting unit 40. Is received at. That is, the optical fiber 62 functions as a light receiving optical fiber. The light transmitted through the optical fiber 62 is emitted from the tip of the optical fiber 62 by the detection unit 41 at the next stage. That is, in the detection unit 41, the optical fiber 62 functions as a light emitting optical fiber.
When the light is reflected by the detection target M, the light is received by the light receiving optical fiber 32 of the detection unit 41, and a detection signal is input to the light reception unit 12. In other words, the light emitting unit 11, the detecting unit 40,
The detecting unit 41 and the light receiving unit 12 are connected in series by one optical path.

Therefore, when the detection target is detected by both the detection unit 40 and the detection unit 41, a detection signal is input to the light receiving unit 12, but if either the detection unit 40 or the detection unit 41 detects the detection target, If the object M cannot be detected, that is, if the reflected light cannot be received, no detection signal is input to the light receiving unit 12, and the AND connection in the logical operation is performed.

FIG. 4 shows an embodiment in which the structure of the above embodiment is partially modified. As shown by detecting sections 40, 41,..., A large number of detecting sections 40 are connected in order by optical fibers 61. Yes, first
The optical fiber cable 20 for light projection is connected to the detection unit 40 at the stage, and the optical fiber 30 for light reception is connected to the detection unit 42 at the last stage. In this manner, an arbitrary number of detection units 40.
Can be linked by AND connection. If the number of the detection units 40 increases, the amount of projected light becomes insufficient. Therefore, two light projection units 11 are provided, and the optical fiber cables 20 connected to each other are collectively sent to the first stage detection unit 40.

The following examples are reference techniques that are not included in the technical scope of the present invention but can be implemented in combination with the present invention.

In the embodiment shown in FIG. 5, an AND-connected output is obtained by a transmission type photoelectric switch. The same reference numerals are given to the same structural parts as those in each of the above-described embodiments, and redundant description will be omitted.

In this embodiment, the light projecting optical fiber cable 20 is divided into two light projecting optical fiber cables 23 from the coupler 70. The divided light emitting optical fiber cables 23, 23 are connected to different light emitting detecting units 43, 43, respectively. Therefore, the light projecting optical fibers 22, 22 connected to the light projecting unit 11 are separately connected to the light projecting detecting units 43, 43, respectively.

Light-receiving detectors 44, 44 are provided opposite to the light-emitting detectors 43, 43, respectively. An optical fiber cable containing the optical fiber 32 for light reception
The two optical fiber cables 33, 33 are combined into one light receiving optical fiber cable 30 by a coupler 70 and connected to the light receiving section 12. The light emitted from the light emitting unit 11 is transmitted from the light emitting optical fiber 22 to the light emitting detecting unit 43, the detection object space, the light receiving detecting unit 44, and the light receiving optical fiber 32 from the light emitting optical fiber 22 for each set of detecting units. Was told,
The light is received by the light receiving unit 12.

The operation of the optical fiber photoelectric switch having such a structure will be described.

When the detection target M interrupts the optical path between the two sets of the light projecting detecting unit 43 and the light receiving detecting unit 44, the light receiving detecting unit 44 at that location cannot receive light. However, if the light is received by at least one of the light-receiving detectors 44, the light is transmitted to the light-receiving unit 12, so that no detection signal is output from the photoelectric switch body 10. If the optical paths of both the detection units are interrupted by the detection target M, the light reception by the light receiving optical fiber 32 and the light receiving unit 12 is interrupted, and a detection signal is output. That is, the detection signals from the two sets of the detection units 43 and 44 are OR-connected in a logical operation and input to the light receiving unit 12.

As shown in FIG. 6, the number of detectors 43 and 44 can be arbitrarily increased. When the number of detectors 43 and 44 is increased and the amount of light is insufficient, the number of light projecting units 11 may be increased.

The embodiment shown in FIG. 7 obtains an OR-connected output by a transmission type photoelectric switch. The same reference numerals are given to the same structural parts as those in each of the above-described embodiments, and redundant description will be omitted.

In this embodiment, the light emitting optical fiber cable 20 accommodating the light emitting optical fiber 22 is connected to the light emitting detecting unit 43 of the first stage, and the light receiving optical fiber is opposed to the light emitting detecting unit 43. A section 44 is provided. One end of an optical fiber cable 65 accommodating the optical fiber 64 is connected to the light receiving detection unit 44. The other end of the optical fiber cable 65 is connected to the second-stage light emitting detection unit 43. A second-stage light-receiving detector 44 is provided opposite to the light-emitting detector 43. The light-receiving optical fiber cable 30 containing the light-receiving optical fiber 32 is connected to the light-receiving detector 44. I have. Therefore, in this embodiment, the optical fiber 64 is
The first-stage detector functions as a light-receiving optical fiber,
The second-stage detector functions as a light-projecting optical fiber.

The operation of the optical fiber type photoelectric switch having the above structure will be described.

The light path from the light emitting unit 11 is a light emitting optical fiber 22,
First stage light projecting detector 43, detection target space, light receiving detector 4
4, the optical fiber 64, the second-stage light emitting detection unit 43, the detection target space, from the light receiving detection unit 44 to the light receiving optical fiber 32,
Since they are connected in series, if the detection target M blocks the optical path in the detection space of either the first stage or the second stage,
Since no light is transmitted to the light receiving optical fiber 32, a detection signal is output. That is, an output in which the detection signals of the first and second stages are OR-connected by a logical operation is input to the light receiving unit 12.

In this embodiment as well, the number of detection stages can be increased by increasing the number of optical fibers 64 between the light projecting detecting unit 43 and the light receiving detecting unit 44 and the number of stages can be increased. Also, as shown in FIG.
It is also possible to compensate for the decrease in the amount of light in the optical path and to improve the sensitivity in the light receiving unit 12.

The arrangement structure of the optical fiber and the detection unit of each embodiment described above may be used alone, but may be implemented by combining the structures of a plurality of embodiments. For example, if the detection signals of a plurality of AND-connected detection units and the detection signals of a plurality of OR-connected detection units are input to the same light receiving unit, a more complicated logical operation output can be achieved. It is also possible to get

〔The invention's effect〕

In the optical fiber type photoelectric switch according to the first and second aspects of the present invention, the optical fiber and the detection unit connected to the light projecting unit and the light receiving unit of the photoelectric switch body are appropriately combined and arranged. With a simple structure, it is possible to input the result of the logical operation of the detection signals from the plurality of detection units to the light receiving unit. That is, unlike the related art, it is not necessary to provide a photoelectric switch for each detecting unit, and a single photoelectric switch body can correspond to a plurality of detecting units. Installation space can be reduced. In the conventional technology for electrically logically operating the output of the photoelectric switch, there is a problem that the internal circuits of the photoelectric switch electrically affect each other. Because we do not use
The above problems are completely eliminated. In addition, since there is no electrical logic operation circuit and the output of the photoelectric switch can be used immediately, the response speed is very fast and various controls can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a structural layout view showing an embodiment of the present invention, and FIGS.
4 is a structural layout diagram showing another embodiment, FIGS. 5 to 8 are structural layout diagrams showing different reference technologies, FIG. 9 is a perspective view of a conventional example, and FIG. 10 (a). , (B) is a circuit configuration diagram. 10 photoelectric switch body, 11 light emitting part, 12 light receiving part, 22 light emitting optical fiber, 32 light receiving optical fiber, 40 to 44 detection part, M detection target

Claims (2)

(57) [Claims] A photoelectric switch body having a light projecting unit, a light receiving unit, and an amplifier unit; an optical fiber connected to the light projecting unit and the light receiving unit; and a detecting unit provided at a tip of the optical fiber. A reflection-type optical fiber photoelectric switch that performs light emission and reception, wherein the optical fiber has one end connected to the detection unit and the other end connected to the light emission unit, and one end connected to the detection unit. A light receiving optical fiber connected to the light receiving portion and the other end is connected to the light receiving portion. There are a plurality of the detecting portions so that information can be individually detected. A plurality of pieces of information detected by the plurality of detection sections are logically operated and input to a light receiving section of the photoelectric switch main body, wherein: switch. 2. A photoelectric detection device comprising: a photoelectric switch body having a light projecting unit, a light receiving unit, and an amplifier unit; an optical fiber connected to the light projecting unit and the light receiving unit; and a detecting unit provided at an end of the optical fiber. An optical fiber photoelectric switch of a reflection unit that transmits and receives light at the detection unit, wherein the detection unit is provided in a plurality of stages, and a first-stage detection unit includes a light-projection optical fiber connected to the light-projection unit, Is connected to one end of another light receiving optical fiber, and the other end of the light receiving optical fiber of the preceding stage detecting unit is connected to the second and subsequent detecting units as the projecting optical fiber of the detecting unit. The other end of the optical fiber for light reception is connected to the other end of the optical fiber for light reception in the detection unit at the last stage, and the other end of the optical fiber for light reception is connected to the light reception unit of the photoelectric switch body. Iba-type photoelectric switch.