JPH0836955A - Multi-stage reflection scanning area sensor - Google Patents

Abstract

PURPOSE:To prevent missing of sensing a small and/or thin object using a simple configuration by installing a light projecting element in specified positional relationship with a plane reflector consisting of a pair of opposingly arranged reflecting boards, and receiving the light from the light projecting element upon iterative reflections by the reflecting boards. CONSTITUTION:A pair of reflecting boards 11, 12 are arranged opposingly so that a plane reflector 1 is formed. A light projecting element 2 is provided. which has an optical axis inclined at a certain angle theta deg. to the normal to the board 11, and the light from the projecting element 2 is interatively reflected by the boards 11, 12 and received by a light receiving element 3, and a sensor circuit, 4 senses any object which has passed the space of this plane reflector and intersected the optical axis. According to this constitution where the light does not make interreflection, a multi-stage reflection scanning area sensor is accomplished which can prevent missing of sensing a small and/or thin object.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the passage and presence of an object in a device for supplying parts and other objects, and more particularly to a multi-stage reflection scanning type area sensor capable of detecting the passage and presence of an object in space. .

[0002]

2. Description of the Related Art In a conventional area sensor, as shown in FIG. 6, a plurality of optoelectronic sensors P and S are arranged facing each other at equal intervals in the longitudinal direction of a pair of supporting columns R facing each other, and calculation is performed from the output thereof. The circuit C detects the presence or absence of an object.

[0003]

The above area sensor is
As is clear from FIG. 6, when a plurality of photoelectric sensors P and S are arranged side by side, they cannot be arranged below a certain pitch due to mutual interference of light, so that a small object or a thin object can be detected. There was a problem that it could not be done.

Further, in the photoelectric sensor, since the projector P and the light receiver S are arranged so as to face each other, a large number of sets of photoelectric sensors P and S are required, resulting in an increase in cost. There was.

Therefore, the inventor of the present invention arranges the optical axis of the light projecting element with a certain angle with respect to the perpendicular line of the one of the reflecting plates, and causes the pair of reflecting plates to be sequentially reflected in multiple stages for scanning. As a result of further research and development focusing on the technical idea of the present invention of detecting with a light receiving element, a small object or a thin object can be prevented from being missed, and the object of the present invention to achieve cost reduction can be achieved. Reached

[0006]

SUMMARY OF THE INVENTION A multi-stage reflective scanning type area sensor according to the present invention (a first invention according to claim 1) comprises a pair of reflecting plates provided with mirror surfaces arranged so as to face each other. Of the light projecting element arranged with its optical axis inclined by a certain angle with respect to the perpendicular of the reflecting plate, and the light projected along the optical axis of the light projecting element is reflected by one of the reflecting plates. Next, by repeating the reflection on the other reflecting plate, it is arranged at a position where the reflected light scanned in the longitudinal direction of the pair of reflecting plates can be received, and an object between the pair of opposing reflecting plates. And a light receiving element for detecting.

According to the multi-stage reflective scanning area sensor of the present invention (the second invention according to claim 2), in the first invention, the pair of reflectors are formed by plane reflectors arranged in parallel. There is something.

The multi-stage reflective scanning type area sensor of the present invention (the third invention according to claim 3) is the same as that of the first invention.
The pair of reflectors are constituted by reflectors provided in parallel with concave reflecting mirror surfaces.

The multistage reflective scanning type area sensor of the present invention (the fourth invention according to claim 4) is different from the first invention in that
A passage detection circuit for detecting an object passing between the pair of reflectors is added based on a change in a signal output from the light receiving element.

The multi-stage reflective scanning area sensor of the present invention (the fifth invention according to claim 5) is different from the first invention in that
The presence / absence detection circuit for detecting the presence / absence of an object between the pair of reflectors is added based on the state of the signal output from the light receiving element.

[0011]

According to the multi-stage reflection scanning type area sensor of the first aspect of the present invention, the optical axis of the light projecting element is arranged so that the optical axis is inclined at a constant angle with respect to the vertical line of the one reflector. The light projected along is repeatedly reflected by one reflection plate and then reflected by the other reflection plate, and is scanned in the longitudinal direction of the pair of reflection plates, and the reflected light is reflected. When the light receiving element receives light, an object between the pair of opposing reflecting plates is detected.

In the multi-stage reflective scanning area sensor of the second invention having the above structure, the optical axis of the light projecting element is arranged so that the optical axis is inclined by a constant angle with respect to the vertical line of the one reflecting plate. The light projected along the line is repeatedly reflected by one of the pair of plane reflecting plates arranged in parallel and then by the other reflecting plate. By scanning the plate in the longitudinal direction and receiving the reflected light by the light receiving element, an object between the pair of opposing reflecting plates is detected.

In the multi-stage reflection scanning type area sensor of the third invention having the above-mentioned structure, the optical axis of the light projecting element is arranged with the optical axis inclined by a certain angle with respect to the perpendicular of the one reflecting plate. The light projected along the line is repeatedly reflected by one of the pair of reflectors having concave reflecting mirror surfaces arranged in parallel and then by the other reflector. Then, the pair of reflection plates are scanned in the longitudinal direction, and the reflected light is received by the light receiving element to detect an object between the pair of opposed reflection plates.

In the multi-stage reflection scanning type area sensor of the fourth invention having the above-mentioned structure, in addition to the operation of the first invention, the passage detecting circuit is arranged to detect the change of the signal output from the light receiving element. It detects an object passing between the plates.

In the multi-stage reflection scanning type area sensor of the fifth invention having the above-mentioned structure, in addition to the operation of the first invention, the presence / absence detection circuit is arranged to detect the pair of reflections based on the state of the signal output from the light receiving element. The presence or absence of an object between the plates is detected.

[0016]

According to the multi-stage reflective scanning area sensor of the first aspect of the present invention, which has the above-mentioned operation, the light is projected from the light projecting element in which the optical axis is inclined by a certain angle with respect to the perpendicular of the one reflecting plate. The reflected light is sequentially reflected on a pair of reflecting plates in multiple stages and scanned to be detected by the light receiving element, so that small objects and thin objects can be prevented from being missed and the cost can be reduced.

In addition to the effect of the first aspect of the invention, the multi-stage reflective scanning area sensor of the second aspect of the invention which has the above-mentioned effect uses a flat reflector, and therefore has the effect of simplifying the structure and reducing the cost.

In addition to the effect of the first aspect of the invention, the multi-stage reflective scanning area sensor of the third aspect of the present invention, which has the above-described operation, uses a reflector plate having a concave reflecting mirror surface. By increasing the scannable distance, it is possible to detect an object in a large space.

In addition to the effect of the first aspect of the invention, the multi-stage reflective scanning area sensor of the fourth aspect of the present invention having the above-described operation can detect an object passing between the pair of reflectors based on a change in the signal output by the light receiving element. This has the effect of enabling detection.

In addition to the effect of the first aspect of the invention, the multi-stage reflective scanning area sensor of the fifth aspect of the present invention which has the above-described operation determines whether or not there is an object between the pair of reflectors based on the state of the signal output by the light receiving element. This has the effect of enabling detection.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) As shown in FIG. 1, the multi-stage reflective scanning area sensor according to the first embodiment includes flat reflecting plates 11 and 12 having plane mirror surfaces arranged in parallel facing each other. A pair of flat reflectors 1 and the one flat reflector 11
And the light projected along the optical axis of the light projecting element 2 is reflected by one reflecting plate 11. Next, by repeating the reflection by the other reflection plate 12, it is arranged at a position where the reflected light scanned in the longitudinal direction of the pair of reflection plates 1 can be received, and the pair of reflection plates facing each other. 11, 12
Between the light receiving element 3 for detecting an object between the light receiving element 3 and the opposing reflecting plate 1 based on the change in the signal output by the light receiving element 3.
Passage detection circuit 4 for detecting an object passing between 1 and 12
It consists of and.

As shown in FIG. 1, the pair of flat reflectors 1 are made up of flat plate members having a predetermined height and width, which are vertically arranged with a certain distance therebetween. And a flat reflection plate 12, and a mirror surface is formed on the opposing inner rectangular plane.

As shown in FIG. 1, the light projecting element 2 is composed of a photoelectric element which projects light in accordance with an electric input arranged above the other flat reflecting plate 12 arranged on the left side in the figure. The reflected light is arranged above the plane mirror surfaces of the pair of flat reflecting plates 1 facing each other with the optical axis inclined by a constant angle θ (the incident angle is determined by this angle) with respect to the perpendicular. Since the light is reflected at a reflection angle θ that is equal to the incident angle, it reaches the mirror surface portion slightly below the other flat reflection plate 12.

That is, the light projected from the light projecting element 2 is reflected at an angle of reflection equal to the incident angle every time the light is totally reflected on the opposite mirror surface as shown by the broken line in FIG. Scanning is sequentially performed so as to reach a mirror surface portion slightly below the flat reflecting plate on one side, the scanning is advanced to below the pair of flat reflecting plates 1, and finally to the lower end of the one flat reflecting plate 11. It is configured.

The light-receiving element 3 is composed of a photoelectric element that outputs an electric signal when receiving light, and below the one flat reflecting plate 11, the other flat reflecting plate 1 is provided.
The optical axis is inclined by a certain angle with respect to the perpendicular of the mirror surface of the second mirror surface, and the reflected light that is scanned by reflecting the flat mirror surfaces of the pair of flat reflecting plates 1 in multiple stages is received, as shown in FIG. It is configured to output various electrical signals.

The passage detecting circuit 4 is connected to the light receiving element 3 and intercepts the optical axis of the reflected light which is multi-stage reflected and scanned when an object passes between the pair of flat reflectors 1. As shown in FIG. 2, the level of the electric signal output from the light receiving element 3 changes from the high level to the low level and from the low level to the high level again. It consists of a detectable structure.

In the multi-stage reflective scanning area sensor of the first embodiment having the above-mentioned structure, the light projecting element 2 projects light along the optical axis inclined downward, and the optical axis is broken line in FIG. Each time a total reflection is performed on the opposite mirror surface, the light is reflected at an angle of reflection equal to the angle of incidence, and is sequentially scanned so as to reach the mirror surface portion slightly below the opposite flat reflecting plate. The reflection plate 1 is sequentially moved downward, and finally reaches the lower direction of the one flat reflection plate 11.

The light receiving element 3 receives the reflected light which is scanned by reflecting the flat mirror surfaces of the pair of flat reflecting plates 1 in multiple stages and outputs an electric signal.

When the object passes between the pair of flat reflectors 1, the passage detection circuit 4 intercepts the optical axis of the reflected light which is multi-stage reflected and scanned, so that the electrical output from the light receiving element 3 is output. Since the signal level changes from the high level to the low level as shown in FIG. 2 and from the low level to the high level again, the passage of an object is detected based on this signal level change.

The multi-stage reflection scanning type area sensor of the first embodiment having the above-described operation is constructed from the light projecting element 2 in which the optical axis is inclined by a constant angle with respect to the perpendicular line of the one flat reflecting plate 11. The projected light is sequentially reflected on the pair of flat reflecting plates 1 in multiple stages and scanned to be detected by the light receiving element 3, so that the small object or the thin object can be prevented from being missed and the pair of photoelectric elements can be detected. Since it is good, it has the effect of reducing the cost.

Since the multi-stage reflective scanning area sensor of the first embodiment uses the pair of flat reflecting plates 1 which are inexpensive and have a simple structure, the structure of the entire apparatus is simplified and the cost is reduced.

Furthermore, in the multi-stage reflective scanning type area sensor of the first embodiment, the passage detecting circuit 4 detects the object passing between the pair of reflecting plates based on the change in the level of the signal output from the light receiving element 3. In addition to the above, when the passing speed of the object is constant, the size of the passing object can be detected from the pulse width of the pulse waveform shown in FIG. This has the effect of making it possible to detect the speed.

(Second Embodiment) As shown in FIG. 3, the multi-stage reflective scanning area sensor of the second embodiment has a pair of circumferential concave surfaces instead of the pair of flat reflectors of the first embodiment. The only difference is that it changes to a cylindrical mirror.

In the multi-stage reflection scanning type area sensor of the second embodiment having the above-mentioned structure, the light projecting element 2 of the light projecting element 2 arranged so that the optical axis thereof is inclined at a constant angle with respect to the perpendicular of the one cylindrical mirror. The light projected along the optical axis is reflected by one of the pair of cylindrical mirrors with a reflecting mirror surface that is a circular concave surface arranged in parallel, and then by the other cylindrical mirror. By repeating the above operation, the pair of cylindrical mirrors are scanned in the longitudinal direction, and the reflected light is received by the light receiving element 3 to detect an object between the pair of opposed cylindrical mirrors. is there.

In addition to the effect of the first embodiment, the multistage reflective scanning type area sensor of the second embodiment having the above-mentioned operation uses a cylindrical mirror having a reflecting mirror surface which forms a circumferential concave surface, and therefore diffuses light. By reducing the scannable distance, that is, by increasing the scannable distance, that is, the total length of the optical axis on which the light projected from the light projecting element 2 is reflected, it is possible to detect an object in a large space. In addition to the effect, it is possible to reduce the light amount of the light projecting element 2 if the spaces are the same.

(Third Embodiment) The multi-stage reflective scanning area sensor of the third embodiment is intended to detect whether or not there are any parts in the parts box 6, and as shown in FIG. The pair of flat reflectors of the first embodiment are arranged at the lower portions of the left and right side walls of the component box, the light projecting element 2 is arranged at one end of the left side wall, and the light receiving element is arranged at the other end of the right side wall. The presence or absence of an object in the space between the pair of flat reflectors 1, that is, in the component box 6 is detected based on the state of the signal output from the light receiving element 3 instead of the passage detection circuit 4 by disposing the element 3. The presence / absence detection circuit 5 is changed.

In the multi-stage reflective scanning area sensor of the third embodiment having the above-mentioned structure, the light projecting element 2 arranged at one end of the left side wall of the component box 6 has the same vertical line as in the first embodiment. The light is tilted and projected, reflected in multiple stages, scanned from one end to the other end (from the front to the back in FIG. 4), and the light receiving element 3 arranged at the other end of the right side wall of the component box 6 reflects the reflected light. And outputs a signal, and the presence / absence detection circuit detects the presence / absence of an object between the pair of reflectors, that is, in the component box 6 based on the state of the signal output by the light receiving element, that is, the presence or absence of the signal. It is a thing.

That is, when there is a component in the component box 6, the reflected light scanned by the multi-stage reflection and scanned is blocked by the component and does not reach the light receiving element 3. When no signal is output from the light receiving element 3 (that is, the signal level is low), it means that there is a component in the component box 6, and conversely, a signal is output from the light receiving element 3 (that is, a signal). Is high) means that there are no parts in the parts box 6.

The multi-stage reflection scanning type area sensor of the third embodiment having the above-mentioned operation is based on the state (level) of the signal output by the light receiving element 3, and the pair of the pair of parts are arranged on both sides of the component box 6. It is possible to detect the presence / absence of an object between the flat reflectors 1.

That is, in the multi-stage reflective scanning type area sensor of the third embodiment, when the state of the signal output from the light receiving element 3 becomes high level as shown in FIG.
Since it can be detected that the parts have been exhausted, it is possible to replenish the parts box 6 with parts.

The above-described embodiments are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

The present invention is based on the above third embodiment.
By adjusting the angle of the optical axis of the light projecting element with respect to the size of the parts and adjusting the pitch of the multi-stage reflection, depending on the degree of passage of the optical axis, the level of the output signal of the light receiving element within the parts box It is also possible to detect the approximate remaining amount of the above parts.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment device of the present invention.

FIG. 2 is a diagram showing an output signal of a light receiving element of the second embodiment.

FIG. 3 is a perspective view showing opposing cylindrical mirrors of a second embodiment device of the present invention.

FIG. 4 is a perspective view showing a third embodiment device of the present invention.

FIG. 5 is a diagram showing an output signal of the light receiving element of the third embodiment.

FIG. 6 is a front view showing a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 pair of plane reflectors 2 light emitting element 3 light receiving element 4 passage detection circuit 11 one plane reflector 12 the other plane reflector

Claims (5)

[Claims] 1. A pair of reflecting plates provided with mirror surfaces arranged opposite to each other, a light projecting element having an optical axis inclined at a constant angle with respect to a perpendicular line of the one reflecting plate, The light projected along the optical axis of the light projecting element is reflected by one reflecting plate and then reflected by the other reflecting plate, so that the light is projected in the longitudinal direction of the pair of reflecting plates. A multi-stage reflective scanning type area sensor comprising a light receiving element which is arranged at a position capable of receiving the reflected light scanned and which detects an object between the pair of opposed reflecting plates. 2. The multi-stage reflective scanning type area sensor according to claim 1, wherein the pair of reflectors are formed by plane reflectors arranged in parallel. 3. The multi-stage reflection scanning type area sensor according to claim 1, wherein the pair of reflection plates are formed of reflection plates having reflection mirror surfaces that are concave and are arranged in parallel. 4. The multi-stage reflection scanning according to claim 1, further comprising a passage detection circuit for detecting an object passing between the pair of reflectors based on a change in a signal output from the light receiving element. Type area sensor. 5. The multi-stage reflection scanning according to claim 1, further comprising a presence / absence detection circuit for detecting the presence / absence of an object between the pair of reflectors based on a state of a signal output from the light receiving element. Type area sensor.