JPH0651072A - Area sensor - Google Patents

Abstract

PURPOSE:To provide an area sensor which can be accomplished at a low cost even though the sensing area is wide and which has a high reliance upon electric contacting. CONSTITUTION:An area sensor is equipped with a light projector 22 and receiver 28 which are arranged on the optical axis 32 while facing one another at a certain spacing, a plurality of reflex mirror units 34 installed between them 22, 28 in longitudinal arrangement, and another plurality of reflex mirror units 40 which are located apart from the first named mirror units 34 and mate with the respective ones 34. Each of the mirror units 34 has a reflex mirror 36 and another 38 which are arranged in an angle whose apex is opened. Each of the other mirror units 40 has a reflex mirror 42 and another 44 which are arranged in an angle form whose apex is left open.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an area sensor which is a kind of transmission type photoelectric switch and which detects the presence or absence of a detection object in a detection area (detection area) having a certain area.

[0002]

2. Description of the Related Art This type of area sensor is used, for example, in a molding machine, a pressing machine or the like to detect when a part of a human body enters a dangerous area.

A conventional example of this type of area sensor is shown in FIG. This area sensor comprises a light projector 4 which emits light 6 and a light receiver 8 which receives the light 6 from it and converts it into an electrical signal.
The transmission type photoelectric switch unit 2 which is a set of
It is composed of many vertically arranged. Each light projector 4 constitutes a light projecting block 10, and each light receiver 8 comprises a light receiving block 1.
Make up 4. 12 and 16 are electric wires.

When a detection object 20 such as a part of a human body enters from somewhere in the detection area 18 between the light projecting block 10 and the light receiving block 14 from the front and back sides of the paper, it is determined which one. The light 6 of the photoelectric switch unit 2 is blocked, and as a result, the presence of the detection object 20 can be detected.

[0005]

However, in the above area sensor, when the detection area 18 becomes wider, a large number of photoelectric switch units 2 are required accordingly,
Therefore, there is a problem that it becomes very expensive.

Further, since a large number of photoelectric switch units 2 constitute one area sensor, it is necessary to electrically connect a large number of photoelectric switch units 2 with a connector or the like. Contact reliability becomes a problem.

Therefore, the main object of the present invention is to provide an area sensor which can be manufactured at a low cost even if the detection area is wide and which has high electrical contact reliability.

[0008]

In order to achieve the above object, an area sensor of the present invention is arranged on one light emitting / receiving axis so as to be opposed to each other with a gap therebetween, and a light projecting device for emitting light. Receiver for receiving the light of the above and converting it into an electric signal, a plurality of first reflecting mirror units arranged in series between the projector and the light receiver, and the first reflecting mirror unit.
And a plurality of second reflecting mirror units respectively corresponding to the respective first reflecting mirror units, and each of the first reflecting mirror units is provided. A first reflecting mirror that reflects incident light from the light emitting / receiving axis in a direction substantially orthogonal to the light emitting / receiving axis, and a light substantially parallel to and opposite in direction to the light from the first reflecting mirror. And a second reflecting mirror that reflects light having a distance in the direction along the projecting / receiving axis onto the projecting / receiving axis, and each of the second reflecting mirror units corresponds to the second reflecting mirror. A third reflecting mirror for receiving the light from the first reflecting mirror of the first reflecting mirror unit and reflecting it in a direction substantially parallel to the light projecting and receiving axis; and a light from the third reflecting mirror And reflects it towards the second reflector of the corresponding first reflector unit. Wherein the fourth reflector and that each have.

In addition, a reflecting mirror unit having a structure in which two double-sided reflecting mirrors are arranged in a box-shape so as to be substantially orthogonal to each other is provided in each of the first reflecting mirror unit and the second reflecting mirror unit.
It may be used for each of the reflecting mirror units.

[0010]

According to the above construction, the light emitted from the projector is sequentially reflected by each of the first reflecting mirror units and each of the second reflecting mirror units, while the light is predetermined in the direction along the light projecting and receiving axis. The light path is shifted by a distance of 1 to form a detection area, and finally the light is incident on the light receiver. When a detection object enters somewhere in this detection area, the light is blocked thereby, and as a result, the presence of the detection object can be detected.

[0011]

1 is a schematic view showing an area sensor according to an embodiment of the present invention. This area sensor is provided with a pair of a light emitter 22 and a light receiver 28 which are arranged on one light emitting and receiving shaft 32 so as to face each other with a space therebetween, and are arranged in tandem between the light emitter 22 and the light receiver 28. A plurality of (three in the illustrated example) first reflecting mirror units 34, and a plurality of (three in the illustrated example), which are arranged apart from the first reflecting mirror unit 34 and respectively correspond to the respective reflecting mirror units 34. (Three) second reflecting mirror unit 40.

The projector 22 has, for example, a light emitting diode, a semiconductor laser or the like, and emits light 24. Reference numeral 26 is an electric wire for the projector 22.

The light receiver 28 has, for example, a photodiode or the like, receives the light 24 emitted from the light projector 22 and reflected by the respective reflecting mirror units 34 and 40, and converts it into an electric signal, for example, an on / off signal. To do. Reference numeral 30 is an electric wire for the light receiver 28.

Each of the reflecting mirror units 34 includes the light emitting and receiving shaft 3 described above.
2 a first reflecting mirror 36 that reflects the light 24 (for example, the light 24a) from above in a direction substantially orthogonal (including orthogonal) to the light emitting and receiving axis 32, and the light 24 (for example, the light 2) from the reflecting mirror 36.
4b) light 24 (for example, 24d) that is substantially parallel (including parallel) and has an opposite direction to the same light 24b and has a distance in the direction along the light emitting / receiving axis 32 is reflected on the light emitting / receiving axis 32. The second reflecting mirror 38 (24e indicates an example of the reflected light) is provided.

The light 24 emitted from the projector 22 is incident on the reflecting mirror 36 of the reflecting mirror unit 34 on the side of the projector 22 and the reflecting mirror 38 of the reflecting unit 34 on the side of the light receiver 28.
The light emitted from is incident on the light receiver 28.

Each reflecting mirror unit 40 includes light 24 (eg, light 24) from the reflecting mirror 36 of the corresponding reflecting mirror unit 34.
b) The third reflecting mirror 42 which receives and reflects it in a direction substantially parallel (including parallel) to the light emitting and receiving axis 32, and the light 24 (for example, the light 24c) from this reflecting mirror 42 is received and is reflected by the third reflecting mirror 42. It has the 4th reflecting mirror 44 (24d shows an example of the reflected light) which reflects toward the reflecting mirror 38 of the corresponding reflecting mirror unit 34, respectively.

With such a structure, the light 24 emitted from the projector 22 is reflected by the first reflecting mirror unit 34 and the second reflecting mirror unit 34.
Are sequentially reflected by the reflecting mirror 40 of the
The light path is shifted by a predetermined distance in the direction along the light emitting / receiving axis 32 to form the detection area 46, and finally the light is incident on the light receiver 28. When the detection object 20 as described above enters somewhere in the detection area 46, the light 24
As a result, the presence of the detection object 20 can be detected.

In this case, the light 24 emitted from the projector 22 is
Is preferably sufficiently narrowed, which prevents the later light 24 from spreading and reducing the amount of light incident on the light receiver 28.

In the area sensor as described above, the detection area 46 can be easily widened and narrowed by increasing or decreasing the number of connected reflecting mirror units 34 and 40.

Further, since the area can be detected by the set of the projector 22 and the light receiver 28, the cost can be reduced even if the detection area 46 is large. This is a set of projector 22 and photoreceiver 28 corresponding to the photoelectric switch unit 2 described above, and a set of reflecting mirror units 34 and 40.
This is because, when the costs of and are compared, the cost of the former having an electric circuit is much higher.

Further, since the combination of the optical units of the reflecting mirror units 34 and 40 is used to detect the area, the electrical connection portion is only in the portion of the set of the projector 22 and the light receiver 28. Therefore, the electrical contact reliability is very high as compared with the conventional one in which a large number of photoelectric switch units 2 are unit-connected.

It is preferable to use a reflecting mirror unit 50 having a structure as shown in FIG. 2 for each of the reflecting mirror units 34 and 40.

The reflecting mirror unit 50 has a structure in which two double-sided reflecting mirrors 54 and 56 are arranged in a housing 52 so as to be in a V shape and substantially orthogonal (including orthogonal) to each other. . The cross-sectional shape of the housing 52 may be quadrangular or circular, and is arbitrary. Double-sided reflecting mirrors 54 and 5
6 has, for example, a structure in which a silver film is sandwiched between two transparent glass plates.

The reflecting mirror unit 50 has a central axis 5
The light 60a from above 8 is reflected by one of the reflecting surfaces of the first double-sided reflecting mirror 54 in a direction substantially orthogonal to the central axis 58 (60b indicates the reflected light). Further, the light 60b is substantially parallel to and opposite in direction to the light 60b.
Light 60c which is distant from the center axis 58 in the direction along the central axis 58
Is reflected on the central axis 58 by one reflecting surface of the second double-sided reflecting mirror 56 (60d indicates the reflected light). Further, the light 60 incident from the opposite side of the light 60b
e is reflected on the central axis 58 by the other reflecting surface of the first double-sided reflecting mirror 54, and is reflected by the other reflecting surface of the second double-sided reflecting mirror 56 to the opposite side of the light 60c (60f is Shows the reflected light).

Therefore, by utilizing the left side surface of the reflecting mirror unit 50 in the drawing, the same operation as that of the first reflecting mirror unit 34 described above can be performed, and by using the right side surface thereof, the above-mentioned second reflecting surface can be obtained. The same operation as that of the reflecting mirror unit 40 can be performed.

Therefore, if such a reflecting mirror unit 50 is used for each of the first reflecting mirror unit 34 and each of the second reflecting mirror units 40 described above, the reflecting mirror units having the same structure can be used, which is even more advantageous. Cost reduction can be achieved.

Various means can be adopted as the means for connecting a plurality of such reflecting mirror units 50 or the above-mentioned reflecting mirror units 34 and 40 in series with each other. For example, these reflector units 34, 4
It is also possible to provide concave and convex portions which are fitted to each other at both ends of 0 and 50 and connect them with each other, or to fit these reflecting mirror units 34, 40 and 50 in series in the cylinder and fix them. You can

[0028]

As described above, according to the area sensor of the present invention, the area can be detected by the set of the projector and the receiver, so that the cost can be reduced even if the detection area is wide.

Further, since the combination of the optical units of the first and second reflecting mirror units is used to detect the area, the electrical connection portion is only provided in the portion of the set of the projector and the receiver. Therefore, the electrical contact reliability is very high.

Further, the reflecting mirror unit having a structure in which two double-sided reflecting mirrors are arranged in a box-shape so as to be substantially orthogonal to each other is the above-mentioned first reflecting mirror unit and each second reflecting mirror unit.
If each is used for each of the reflecting mirror units, all of the reflecting mirror units having the same structure will suffice, and the cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an area sensor according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a reflecting mirror unit used in the area sensor of FIG.

FIG. 3 is a schematic view showing an example of a conventional area sensor.

[Explanation of symbols]

 20 detection object 22 light projector 24 light 28 light receiver 32 light emitting / receiving axis 34 first reflecting mirror unit 36 first reflecting mirror 38 second reflecting mirror 40 second reflecting mirror unit 42 third reflecting mirror 44 fourth Reflector 46 Detection area 50 Reflector unit 52 Housing 54, 56 Double-sided reflector

Claims (2)

[Claims] 1. A light emitter, which is arranged on one light emitting / receiving axis so as to face each other at a distance from each other, emits light, and a light receiver which receives light from the light emitter and converts it into an electric signal, and the light emitter. And a plurality of first reflecting mirror units that are arranged in tandem between the light receiving device and the light receiving device, and a plurality of first reflecting mirror units that are arranged apart from the first reflecting mirror units and that correspond to the respective first reflecting mirror units. Second reflection mirror unit, and each of the first reflection mirror units reflects the incident light from the projection / reception axis in a direction substantially orthogonal to the projection / reception axis. A mirror and a light which is substantially parallel to and opposite in direction to the light from the first reflecting mirror, and reflects on the light emitting and receiving axis a distance away from the light in the direction along the light emitting and receiving axis. And each of the second reflection mirrors, The mirror unit receives a light from the first reflecting mirror of the corresponding first reflecting mirror unit and reflects the light in a direction substantially parallel to the projecting / receiving axis, and a third reflecting mirror. An area sensor, comprising: a fourth reflecting mirror which receives light from the mirror and reflects the light toward the second reflecting mirror of the corresponding first reflecting mirror unit. 2. A reflecting mirror unit having a structure in which two double-sided reflecting mirrors are arranged in a housing so as to be substantially V-shaped and substantially orthogonal to each other, the first reflecting mirror unit and the second reflecting mirror are provided. The area sensor according to claim 1, which is used in each unit.