JPH0594931U - Retro-reflective photoelectric switch - Google Patents

Abstract

(57) [Abstract] [Purpose] The retroreflective photoelectric switch of the present invention eliminates the need for increasing the positional accuracy of the reflector and the light emitting element and the light receiving element. [Structure] Projecting beam 21a and receiving beam 22a
Is overlapped in a direction (arrow Q direction) orthogonal to the plane including the optical axes 21b and 22b of the light projecting element 21 and the light receiving element 22, and the both optical axes 21b and 22b are long.
The width is narrow and overlaps in the direction parallel to the plane including the arrow (direction of arrow R). As a result, even if there is a positional error of the reflecting plate 12 in the longitudinal direction (direction of arrow Q) of the overlapping portion 23 of the projected beam 21a and the received beam 22a, the reflecting plate 12 will have a positional error.
Does not deviate from the detection area.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a retroreflective photoelectric switch that performs various detections based on the presence or absence of light reflected from a reflector.

[0002]

[Prior Art]

 Conventionally, in a retroreflective photoelectric switch, a light projecting element projects light toward the reflector plate, and the light reflected by the reflector plate is received by a light receiving element. I am trying to do it.

By the way, in this type of retroreflective photoelectric switch, as seen in Japanese Utility Model Laid-Open No. 3-58837, a foreign object having a high reflectance (for example, white paper) is provided in the vicinity of the light receiving element. It is necessary to reduce the overlap between the emitted light beam and the received light beam so that they will not be detected.

It is also desired to enable detection at a long distance. For this purpose, as shown in FIGS. 17 and 18, the light projected by the light projecting element 1 and the light receiving element 2 are transmitted. It is necessary to thin the overlapping portion 3 with the received beam of. In addition, 4 is a reflector.

However, in such a photoelectric switch 5, since the overlapping portion 3 is thin, the positional accuracy of the light projecting element 1 and the light receiving element 2 and the reflecting plate 4 must be increased.

In particular, when the reflecting plate 4 is provided on the moving body 6 that moves in the direction of arrow A as shown in FIG. 19, in the above-described photoelectric switch 5, the moving body 6 reaches the position shown by the chain double-dashed line. However, there is a problem that this cannot be detected and the detectable area Lj is small.

[0007] Such a problem could be similarly applied to the carrier type self-propelled conveyor disclosed in Japanese Utility Model Publication No. 3-13461. That is, as shown in FIG. 20, a concave reflector (mirror plate) 8 at the rear of the carrier 7, which is a moving body, emits light and receives light by the photoelectric switch 5 at the front of the succeeding carrier 7. , Career 7 is trying to prevent conflicts between colleagues. In this case, since the overlapping portion 3 of the projected beam and the received beam is thin, there is a problem that a larger reflector 8 is required as the traveling path becomes sharper.

[0008]

[Problems to be solved by the device]

 As described above, if the overlapping portion 3 of the light emitting beam and the light receiving beam is made thin, the probability of erroneously detecting a foreign object having a high reflectance at a short distance is reduced, but the light emitting element and the light receiving element are combined with the reflector. Position accuracy must be increased, especially when a reflector is provided on the moving body, the detectable area of the reflector becomes small and a large reflector is required. There was a problem such as becoming.

The present invention has been made in view of the above circumstances, and an object thereof is not only to reduce the probability of erroneously detecting a foreign object having a high reflectance at a short distance, but also to provide a light emitting element and a light receiving element. It is not necessary to increase the positional accuracy of the element and the reflector, and when the reflector is provided on the moving body, the detectable area of the reflector can be made large, and the moving body can be detected satisfactorily at any distance. Another object of the present invention is to provide a regressive reflection type photoelectric switch which can be made small and which can be made smaller in size when used in a carrier type self-propelled conveyor.

[0010]

[Means for Solving the Problems]

 The recursive reflection type photoelectric switch of the present invention projects the light emitted from the light projecting element through the projecting optical element, reflects the light by the reflecting plate, and receives the light reflected by the reflecting plate. In a device in which the light receiving element is made to receive light through the light emitting element and the light receiving optical element, the light projecting beam and the light receiving beam are orthogonal to a plane including both optical axes of the light projecting element and the light receiving element. It has a feature in that it is configured so that it overlaps in a long direction and is narrow in a direction parallel to the plane including both optical axes.

[0011]

[Action]

 According to the above means, the light projecting optical element and the light receiving optical element are configured such that the light projecting beam and the light receiving beam overlap each other in a direction orthogonal to a plane including both optical axes of the light projecting element and the light receiving element. Therefore, even if there is a positional error of the reflecting plate in the longitudinal direction of the overlapping portion, the reflecting plate does not fall out of the detection area.

In this case, since the projected beam and the received beam are narrowly overlapped in the direction parallel to the plane including both optical axes, a foreign object having a high reflectance is erroneously detected at a short distance. This problem can be minimized.

[0013]

【Example】

 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. First, in FIG. 5, a reflecting plate 12 is attached to the moving body 11, and the moving body 11 is adapted to move along the traveling path 13 in the direction of arrow A. The reflector 12 is configured to return the reflected light in the incident direction.

A photoelectric switch 14 is provided outside the traveling path 13. The principle structure of the photoelectric switch 14 is shown in FIGS. The details of the optical element are shown in FIGS.

As shown in FIG. 3, the lens 15 is formed by forming two convex lens portions 17 and 18 on the other surface portion of the concave lens portion 16 of which one surface portion is concave. The lower half portion 16a of the portion 16 and the convex lens portion 17 constitute a light projecting lens portion 19 which is a light projecting optical element, and the upper half portion 16b of the concave lens portion 16 and the convex lens portion 18 form a light receiving lens which is a light receiving optical element. The part 20 is configured.

Therefore, by the light projecting lens unit 19, the light projecting beam 21a from the light projecting element 21 includes both optical axes 21b and 22b of the light projecting element 21 and the light receiving element 22, as shown in FIG. The light is diffused in the direction orthogonal to the plane (direction of arrow Q), and becomes parallel light in the direction parallel to the plane including both optical axes 21b and 22b (direction of arrow R).

Further, the light receiving beam 22a to the light receiving element 22 is in a relation that it is more diffused than the light projecting beam 21a as a whole by the light receiving lens portion 20, but is on a plane including both optical axes 21b and 22b. The light is diffused in a direction (arrow Q direction) orthogonal to the light, and becomes parallel light in a direction (arrow R direction) parallel to the plane including both optical axes 21b and 22b.

As a result, as shown in FIG. 1, the projected beam 21a and the received beam 22a are orthogonal to the plane including the optical axes 21b and 22b of the projecting element 21 and the receiving element 22 (arrow Q). Direction) and a narrow width in the direction (arrow R direction) parallel to the plane including the optical axes 21b and 22b.

As a result, as is clear from a comparison with FIG. 18, there is a positional error of the reflection plate 12 in the longitudinal direction (direction of arrow Q) of the overlapping portion 23 of the projection beam 21a and the reception beam 22a. However, the reflector 12 does not fall out of the detection area.

In this case, since the projection beam 21a and the reception beam 22a are narrowly overlapped in the direction (arrow R direction) parallel to the plane including the optical axes 21b and 22b, white It is possible to minimize the inconvenience of erroneously detecting a foreign object with high reflectance such as paper at a short distance.

In FIG. 5, the moving body 11 and the photoelectric switch 14 are viewed from above, and therefore the light projecting element 21 and the light receiving element 22 are in a vertical relationship. Then, as shown in FIG. 5, the overlapping portion 23 of the projected light beam 21a and the received light beam 22a is in the range shown by the diagonal lines. As seen from the comparison with FIG. 19, the overlapping portion 23 extends in the direction of the arrow Q when seen two-dimensionally, so that the detectable area La of the moving body 11 is longer than the conventional detectable area Lj.

In such a photoelectric switch 14, both beams 21a and 22a are diffused in one direction (arrow Q direction) of the directions orthogonal to the plane including both optical axes 21b and 22b. Since the configuration is such that diffusion in the other direction (direction of arrow S in FIG. 1) is reduced, useless spread of light can be eliminated, and reduction in received light amount can be prevented as much as possible.

FIG. 6 shows a second embodiment in which the photoelectric switch 14 having the above-mentioned configuration is used in a carrier type self-propelled conveyor, and in this case, the overlapping portion 23 becomes wider in plan view. Therefore, the detectable area for the reflecting plate 24 becomes large, the size of the reflecting plate 24 does not need to be so large, and there is no problem even if the curve of the traveling path 25 is configured to be a sharp curve.

The light projecting lens unit and the light receiving lens unit are not limited to the configurations of the light projecting lens unit 19 and the light receiving lens unit 20 of the first embodiment, and the following third embodiment to third embodiment will be described. It may be as in the seventh embodiment.

7 and 8 show a third embodiment. As shown in FIG. 7, two convex lens portions 32 and 33 are integrally formed on the specially shaped convex lens portion 31 to form a light projecting lens portion 34 and a light receiving lens portion 35. Further, in this case, when the state of the optical path of the projected beam (received beam) is seen from the direction of arrow U a in FIG. 7, the light is diffused as shown in FIG. 8, and the projected light when seen from the direction of arrow Va in FIG. The states of the optical paths of the beam and the received beam are similar to those in FIG. 2 described above.

9 and 10 show a fourth embodiment. As shown in FIG. 9, two convex lens portions 42 and 43 are integrally formed on the convex lens portion 41 to form a light projecting lens portion 44 and a light receiving lens portion 45. Further, in this case, when the state of the optical path of the projected beam (received beam) is seen from the direction of the arrow Ub in FIG. 9, the light is diffused as shown in FIG. The optical paths of the beam and the received beam are the same as in FIG. 2 described above.

11 and 12 show a fifth embodiment. As shown in FIG. 11, a light projecting lens unit 51 and a light receiving lens unit 52 are respectively composed of two convex toric lens units. Further, in this case, when the state of the optical path of the projected beam (received beam) is seen from the direction of arrow Uc in FIG. 11, it is diffused as shown in FIG. The state of the optical path of the received beam is similar to that of FIG. 2 described above.

13 and 14 show a sixth embodiment. As shown in FIG. 13, a light projecting lens unit 61 and a light receiving lens unit 62 are respectively composed of two concave toric lens units. Further, in this case, when the state of the optical path of the projected beam (received beam) is seen from the direction of the arrow Ud in FIG. 13, it is diffused as shown in FIG. The state of the optical path of the received beam is similar to that of FIG. 2 described above.

15 and 16 show a seventh embodiment. As shown in FIG. 15, two convex lens portions 72 and 73 are integrally formed on the concave lens portion 71 to form a light projecting lens portion 74 and a light receiving lens portion 75. Further, in this case, when the state of the optical path of the projected beam (received beam) is seen from the direction of arrow Ue in FIG. 15, it is diffused as shown in FIG. 16, and the projected beam when seen from the direction of arrow Ve in FIG. The state of the optical path of the received beam is the same as that shown in FIG.

[0030]

[Effect of the device]

 As is clear from the above description, the recursive reflection type photoelectric switch of the present invention can reduce the probability of erroneously detecting a foreign object having a high reflectance at a short distance, and at the same time, can be used as a light emitting element, a light receiving element and a reflector. It is not necessary to increase the position accuracy of the moving object, and when the reflecting plate is provided on the moving body, the detecting area of the reflecting plate can be made large, so that the moving object can be detected satisfactorily at both near and far, When it is used in a self-propelled conveyor, it has excellent effects such as making the reflector smaller.

[Brief description of drawings]

FIG. 1 is a front view according to the first embodiment of the present invention, showing a state in which a light projecting beam and a light receiving beam overlap with each other.

FIG. 2 is a side view showing how the projected beam and the received beam overlap each other.

FIG. 3 is a perspective view of a lens

FIG. 4 is a plan view showing a state of a projected beam (received beam).

FIG. 5 is a plan view showing a reflector attached to a moving body.

FIG. 6 is a plan view showing a second embodiment in which the present invention is applied to a carrier type self-propelled conveyor.

FIG. 7 is a perspective view of a lens showing a third embodiment of the present invention.

FIG. 8 is a plan view showing a state of a projected beam (received beam).

FIG. 9 is a perspective view of a lens showing a fourth embodiment of the present invention.

FIG. 10 is a plan view showing a state of a projected beam (received beam).

FIG. 11 is a perspective view of a lens showing a fifth embodiment of the present invention.

FIG. 12 is a plan view showing a state of a projected beam (received beam).

FIG. 13 is a perspective view of a lens showing a sixth embodiment of the present invention.

FIG. 14 is a plan view showing a state of a projected beam (received beam).

FIG. 15 is a perspective view of a lens showing a seventh embodiment of the present invention.

FIG. 16 is a plan view showing a state of a projected beam (received beam).

FIG. 17 is a view corresponding to FIG. 2 showing a conventional example.

FIG. 18 is a view equivalent to FIG.

FIG. 19 is a view corresponding to FIG.

FIG. 20 is a view equivalent to FIG.

[Explanation of symbols]

11 is a moving body, 14 is a photoelectric switch, 15 is a lens, 1
Reference numeral 9 is a light projecting lens unit (light projecting optical element), 20 is a light receiving lens unit (light receiving optical element), 21 is a light projecting element, 22 is a light receiving element, 21a is a light projecting beam, 21b is an optical axis, and 22a is a light receiving beam. , 22b is an optical axis, 23 is an overlapping portion, 24 is a reflector, 34 is a light projecting lens unit, 35 is a light receiving lens unit, 44 is a light projecting lens unit, 45 is a light receiving lens unit, 51 is a light projecting lens unit, and 52 is a light projecting lens unit. Is a light receiving lens portion, 61 is a light emitting lens portion, 62 is a light receiving lens portion, 74 is a light emitting lens portion, and 75 is a light receiving lens portion.

Claims (1)

[Scope of utility model registration request] 1. The light emitted from a light projecting element is projected through a light projecting optical element, the light is reflected by a reflecting plate, and the light reflected by the reflecting plate is received by a light receiving optical element. In the light receiving element, the light projecting optical element and the light receiving optical element are overlapped in a direction in which the light projecting beam and the light receiving beam are orthogonal to a plane including both optical axes of the light projecting element and the light receiving element. A retroreflective photoelectric switch, characterized in that the photoelectric conversion switch has a narrow width and overlaps in a direction parallel to a plane including both optical axes.