JP6269015B2 - Photoelectric sensor head - Google Patents

Description

  The present invention relates to a photoelectric sensor head, and more particularly to a sensor head for a coaxial retroreflection photoelectric sensor.

As a photoelectric sensor used for detecting the presence or absence of an object, a reflection photoelectric sensor using light reflection is known. Among reflective photoelectric sensors, there is a so-called regressive reflective photoelectric sensor.
A retroreflective photoelectric sensor generally includes a sensor head incorporating a light emitting element and a light receiving element, and a retroreflective plate (hereinafter also referred to as a reflector). When using the retro-reflective photoelectric sensor, the light emitter / receiver and the reflector are arranged to face each other. When there is no object on the optical path of the light emitted from the light emitting element, the light is reflected by the reflector and enters the light receiving element. On the other hand, when an object is present on the optical path, the light emitted from the light emitting element is blocked by the object, so that the amount of light incident on the light receiving element is reduced. That is, the amount of light received by the light receiving element varies depending on whether an object is present on the optical path. The retroreflective photoelectric sensor detects the presence or absence of an object based on the difference in the amount of received light.

  Further, the retroreflective photoelectric sensor includes a twin-lens type and a coaxial type, and in the case of the coaxial type, the light projecting path and the light receiving path are substantially coincided with each other by a polarizing means such as a polarizing beam splitter (PBS). Separate the light projecting path and the light receiving path.

JP 2009-289739 A

In the case of a coaxial retroreflective photoelectric sensor, the light projecting path and the light receiving path are not physically separated, so the light path is separated by the polarizing means, but the light from the projector partially becomes stray light and the sensor head And is incident on the light receiving element.
Since the amount of stray light is small, there is not much influence when simply determining the presence or absence of a normal object. However, when the object is, for example, a transparent body, the difference in the amount of received light due to the presence or absence is very small. Therefore, stray light affects the amount of received light, and the SN ratio is deteriorated. As a result, it affects the stability of detection accuracy by the photoelectric sensor.

  An object of the present invention is to provide a photoelectric sensor head effective in increasing the detection accuracy of the photoelectric sensor.

  According to one aspect of the present invention, the photoelectric sensor head includes a light projecting unit that emits light, a light separating unit, a light receiving unit, a reflecting unit, and a reflecting surface. The light separating unit is provided on the optical path of the outgoing light from the light projecting unit, and the outgoing light and the reflected light that is reflected and returned from the outside and forms a coaxial optical path with the outgoing light are incident. To do. The light receiving unit has a light receiving surface that receives the reflected light separated from the optical path coaxial with the outgoing light by the light separating unit. The reflection unit is disposed at a position facing the light receiving surface and reflects stray light that goes out of the optical path of the emitted light. The reflection surface is formed in the reflection portion and has a predetermined angle with respect to the light receiving surface so that the reflected stray light travels in the outward direction of the light receiving surface.

  Since the photoelectric sensor head according to the present invention can reduce the amount of stray light reflected in the photoelectric sensor head that enters the light receiving unit, the accuracy of object detection by the photoelectric sensor can be improved.

1 is a schematic configuration diagram of an entire photoelectric sensor according to an embodiment. FIG. The block diagram which abbreviate | omits and shows the inside of the sensor head of the photoelectric sensor. The perspective view of the case of the sensor head of the photoelectric sensor. The figure which shows the optical path in the inside of the sensor head of the photoelectric sensor by a comparative example. The figure which shows the optical path in the sensor head of the photoelectric sensor which concerns on this Embodiment. The figure which shows typically the structure of the reflection part of the photoelectric sensor. The figure which shows schematically the position of the said reflection part, and the optical path of a stray light. The figure for demonstrating the structure of the reflection part. The figure which shows the structure of the reflection part which concerns on the modification 1 typically. The figure which shows the structure of the reflection part which concerns on the modification 2 typically. The figure which shows the structure of the reflection part which concerns on the modification 3 typically. The figure which shows the structure of the reflection part which concerns on the modification 4 typically.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.
In addition, in order for those skilled in the art to provide a thorough understanding of the present disclosure, the accompanying drawings and the following description are provided, and are not intended to limit the subject matter described in the claims.

(Embodiment)
[1-1 Configuration]
[1-1-1 Configuration of Photoelectric Sensor]
FIG. 1 schematically shows the overall configuration of a photoelectric sensor according to an embodiment of the present invention. The photoelectric sensor 1 includes a sensor head 10 (an example of a photoelectric sensor head), a reflector 30, a cable 40, and an amplifier unit 50. The photoelectric sensor 1 is a so-called coaxial retroreflective photoelectric sensor in which a light projecting path and a light receiving path are separated by an optical element (polarizing beam splitter, half mirror, etc.) inside the sensor head 10.

As will be described later, the sensor head 10 includes a light projecting unit and a light receiving unit, and forms an optical path including the emitted light LP from the light projecting unit and the reflected light LR to the light receiving unit with the reflector 30. The reflector 30 is, for example, a retroreflective plate in which a large number of corner cubes are arranged, and is arranged to face the sensor head 10 with a certain detection distance. Between the sensor head 10 and the reflector 30 disposed so as to face each other, an optical path of the emitted light LP and the reflected light LR is formed. The detection object S passes on a transfer path arranged so as to cross the optical path. The sensor head 10 is connected to the amplifier unit 50 via a cable 40 in which a power supply line, a signal line, and the like are integrated. The amplifier unit 50 includes an amplifying unit, a control unit, and a power supply unit. The amplifier unit 50 receives a signal from the sensor head 10 and supplies a driving voltage to the sensor head 10 from the power supply unit.
In the illustrated example, the sensor head 10 and the amplifier unit 50 are separated, but a part or all of the amplifier unit 50 may be built in the sensor head 10.

[1-1-2 Configuration of sensor head]
FIG. 2 shows the sensor head 10 with a part of the internal configuration omitted. The sensor head 10 includes a case 11, a light emitting element 13 provided in the case 11, a light projecting lens 14, a polarization beam splitter 17 (an example of a light separation unit), a light receiving lens 15, a light receiving element 16, The light projecting / receiving port 18 and the reflecting portion 19 which is a feature of the present embodiment are provided. The light emitting element 13 and the light projecting lens 14 constitute a light projecting unit 21 (an example of a light projecting unit). The light receiving lens 15 and the light receiving element 16 constitute a light receiving unit 22 (an example of a light receiving unit).

As shown in FIG. 3, the case 11 is integrally formed of a black resin material and covers each component of the sensor head 10. Further, as shown in the figure, in a part of the inner wall of the case 11, a reflection portion 19 is formed at a position near the light projecting / receiving port 18 and facing the light receiving portion 22.
The light emitting element 13 is composed of a laser diode or the like that emits laser light, and emits outgoing light LP. The emitted light LP passes through the light projecting lens 14 and the polarization beam splitter 17 and is emitted from the light projecting / receiving port 18 toward the outside of the sensor head 10. The light projecting lens 14 is disposed in front of the light emitting element 13 (light projecting side).

The polarization beam splitter 17 is disposed in front of the light projecting lens 14 on the optical path of the outgoing light LP. The polarization beam splitter 17 is an optical element that separates the optical path of the outgoing light LP emitted from the light emitting element 13 and the optical path of the reflected light LR that is the light reflected from the outgoing light LP and returned to the reflector 30. The polarization beam splitter 17 may be replaced with a half mirror.
The light receiving lens 15 is disposed at a position facing the polarization beam splitter 17 and is disposed substantially orthogonal to the emission direction of the emitted light LP. The light receiving element 16 is configured by a photodiode, a phototransistor, or the like, and is disposed to face the polarization beam splitter 17 with the light receiving lens 15 interposed therebetween. The light receiving element 16 receives the reflected light LR from the polarization beam splitter 17 through the light receiving lens 15.

The light projecting / receiving port 18 passes the emitted light LP from the light projecting unit 21 to the outside of the sensor head 10 and passes the reflected light LR from the reflector 30 to the inside of the sensor head 10.
The reflection portion 19 is a part of the inner wall of the case 11 and is formed at a position facing the polarization beam splitter 17. The reflection unit 19 also faces the light receiving unit 22 with the polarization beam splitter 17 interposed therebetween. The size (range) of the reflection portion 19 is determined in proportion to the diameter of the laser light emitted from the light emitting element 13. That is, the reflecting portion 19 is formed wider as the laser diameter is larger. Details of the reflection unit 19 will be described later.

[1-2 Operation]
Hereinafter, the operation of the photoelectric sensor 1 will be described with reference to FIGS. 1 and 2.
The amplifier unit 50 supplies a drive voltage to the sensor head 10 via the cable 40. The sensor head 10 receives this drive voltage and emits laser light from the light projecting unit 21. The emitted light LP, which is laser light emitted from the sensor head 10, is incident on the light projecting lens 14 disposed on the same optical axis as the light projecting unit 21. The outgoing light LP passes through the light projection lens 14 and then enters the polarization beam splitter 17. The outgoing light LP passes through the polarization beam splitter 17 and is emitted from the light projecting / receiving port 18 toward the reflector 30 to the outside of the sensor head 10. The emitted light LP is reflected by the reflector 30 to become reflected light LR, and returns into the sensor head 10 through the light projecting / receiving port 18. As a result, an optical path for the outgoing light LP and the reflected light LR is formed between the sensor head 10 and the reflector 30. That is, the reflected light LR has an optical path coaxial with the outgoing light LP and travels in a direction opposite to the outgoing light LP. As shown in FIG. 1, the coaxial optical path here refers to the path of the outgoing light LP that enters the polarization beam splitter 17 and exits to the outside, and the reflection that returns from the outside and enters the polarization beam splitter 17. It is an optical path along the same axis including the path of the light LR.

  The reflected light LR that has entered the sensor head 10 enters the polarization beam splitter 17. The reflected light LR is separated from the optical path coaxial with the outgoing light LP by the polarizing beam splitter 17 in the direction of the light receiving unit 22 and enters the light receiving element 16 via the light receiving lens 15. The light receiving element 16 receives the reflected light LR and generates an electrical signal having an intensity corresponding to the amount of the reflected light LR received. The sensor head 10 outputs the generated electrical signal to the amplifier unit 50 via the cable 40. The amplifier unit 50 detects the presence or absence of an object based on the electrical signal, or outputs a signal indicating the amount of light received by the sensor head 10.

  Through the light projecting / receiving operation as described above, the photoelectric sensor 1 detects the presence or absence of an object based on the amount of light received by the sensor head 10. When the detection object S is not located in a predetermined detection region on the optical path of the emitted light LP, the emitted light LP emitted from the sensor head 10 is reflected by the reflector 30 to become reflected light LR and enters the light receiving unit 22 of the sensor head 10. To do. On the other hand, when the detection object S is located in the detection region on the optical path, the emitted light LP from the light projecting unit 21 of the sensor head 10 is blocked by the detection object S, so that the amount of reflected light LR received by the light receiving unit 22 Decrease. That is, since the amount of light received by the light receiving unit 22 of the sensor head 10 differs depending on whether or not the detection object S is located in the detection region, the presence or absence of the object is detected based on the difference in the amount of received light.

[1-3 Reflector]
[1-3-1 Comparative Example]
FIG. 4 schematically shows a sensor head 10 ′ according to a comparative example and its optical path. The sensor head 10 ′ is different from the sensor head 10 according to the present embodiment in that the reflecting portion 19 is not formed on the case 11 ′. Hereinafter, the light projecting / receiving operation by the sensor head 10 'according to the comparative example will be described.

  The outgoing light LP from the light emitting element 13 passes through the polarizing beam splitter 17 through the light projecting lens 14, passes through the light projecting / receiving port 18, and is emitted outside. The emitted light LP is reflected by the reflector 30 to become reflected light LR, and the reflected light LR returns from the light projecting / receiving port 18 to the polarization beam splitter 17. The reflected light LR from the polarization beam splitter 17 passes through the light receiving lens 15 and enters the light receiving element 16.

  In the above, some of the light components emitted from the light emitting element 13 do not pass through the polarization beam splitter 17 and travel toward the inner wall surface of the case 11 as stray light LS as shown in FIG. The stray light LSR ′ reflected on the inner wall surface of the case 11 returns to the light receiving unit 22 at a position facing the inner wall surface. As a result, the amount of light received by the light receiving element 16 changes due to the stray light LSR ′, resulting in a problem that the SN ratio is deteriorated.

Of the reflected stray light LSR ′, the amount of light incident on the light receiving unit 22 is relatively small, and conventionally, there was not much influence on simple detection such as detecting the presence or absence of the detection object S. However, when the detection object S is an object such as a transparent body, detection is performed based on a minute difference in the amount of received light. Therefore, even if the amount of the stray light LSR ′ incident on the light receiving unit 22 is small, there is a problem in the stability of detection accuracy.
For example, in the case of detection by laser light emission, the stray light LS from the polarization beam splitter 17 is approximately 5% with respect to the total light emission amount of 100%. Of the stray light LS, the stray light LSR ′ reflected by the inner wall surface of the case 11 is approximately 0.5% of the total light emission amount of 100%, and the amount entering the light receiving unit 22 is approximately 0.05%. . On the other hand, when the detection object S is a transparent body or the like, the amount of the reflected light LR received by the light receiving unit 22 has a small difference caused by the presence or absence of the detection object. Therefore, even if the amount of stray light LSR ′ entering the light receiving unit 22 is small as described above, detection of an object such as a transparent body is affected, and there is a possibility that accurate object detection cannot be performed.

[1-3-2 Function and Configuration of Reflector]
The sensor head 10 according to the present embodiment includes a structure that prevents stray light LSR reflected on the inner wall surface of the case 11 from returning to the light receiving unit 22. Hereinafter, the function and configuration of the reflection unit will be described with reference to FIGS. 5 to 8.

FIG. 5 schematically shows the sensor head 10 and its optical path according to the present embodiment.
The outgoing light LP emitted from the light emitting element 13 passes through the polarizing beam splitter 17 through the light projecting lens 14, passes through the light projecting / receiving port 18, and is emitted to the outside. The emitted light LP is reflected by the reflector 30 to become reflected light LR, and the reflected light LR returns from the light projecting / receiving port 18 to the polarization beam splitter 17. The reflected light LR from the polarization beam splitter 17 passes through the light receiving lens 15 and enters the light receiving element 16.

  All the light components of the outgoing light LP from the light emitting element 13 are reflected without passing through the polarization beam splitter 17 and travel to the inner wall surface of the case 11 as stray light LS as shown in FIG. The stray light LSR reflected on the inner wall surface of the case 11 travels at a predetermined angle by the reflecting portion 19 formed on the inner surface. As a result, the amount of the reflected stray light LSR returning to the light receiving unit 22 via the polarization beam splitter 17 can be significantly reduced.

FIG. 6 schematically shows the structure of the reflecting portion 19. FIG. 6A is a cross-sectional view of the reflecting portion 19, and FIG. 6B is a plan view of the reflecting portion 19. As shown in FIG. 6A, the reflection section 19 has a plurality of triangular prisms in cross section and a plurality of rows of triangular prisms in plan view.
FIG. 7 schematically shows the position of the reflection unit 19 with respect to the light receiving unit 22 and the optical path of stray light. In the drawing, reference numeral 22 a indicates a light receiving surface of the light receiving element 16. The light receiving surface 22 a is a surface through which light enters the light receiving element 16. The reflection unit 19 is disposed so as to face the light receiving surface 22a with the polarization beam splitter 17 (not shown in FIG. 7) interposed therebetween. The reflection part 19 is further formed such that all the reflection surfaces 19a have a predetermined angle with respect to the light receiving surface 22a. The reflection surface 19a is formed so as to face in two directions and have no surface parallel to the light receiving surface 22a.

  As shown in FIG. 7, the stray light LS from the polarization beam splitter 17 (not shown in FIG. 7) travels toward the reflection unit 19. In the reflection part 19, the surface (namely, surface parallel to the light-receiving surface 22a) orthogonal to the advancing direction of the stray light LS is not formed. On the other hand, the plurality of reflecting surfaces 19a formed on the reflecting portion 19 are all formed to have a predetermined angle with respect to the light receiving surface 22a. Therefore, the light which hits the reflective surface 19a among the stray light LS is reflected according to the angle of the reflective surface 19a.

As shown in FIG. 8, the predetermined angle θ1 of the reflecting surface 19a with respect to the light receiving surface 22a is, for example, about 45 °. This corresponds to the incident angle θ2 of the stray light LS traveling substantially perpendicular to the light receiving surface 22a with respect to the reflecting surface 19a (VL in FIG. 8 is a perpendicular to the reflecting surface 19a).
With the above configuration, the stray light LS from the polarization beam splitter 17 is reflected by the reflection surface 19a, and most of the reflected stray light LSR travels outside the perpendicular VL of the reflection surface 19a (outward direction of the light receiving surface 22a). As a result, since the reflected stray light LSR travels so as to avoid the light receiving unit 22, the amount of the reflected stray light LSR incident on the light receiving unit 22 can be significantly reduced.

[1-4 Modification]
In the said embodiment, the form of the reflection part 19 is not limited to said thing. Hereinafter, modified examples of the reflection unit 19 will be described.
[1-4-1 Modification 1]
FIG. 9 shows the structure of the reflecting portion 119 formed on the inner surface of the case 11 according to the first modification. 9A is a cross-sectional view of the reflecting portion 119, FIG. 9B is a plan view of the reflecting portion 119, and FIG. 9C is a perspective view of the reflecting portion 119 viewed from the light receiving portion 22 side. is there. As shown in the figure, the reflecting portion 119 has a plurality of triangular shapes in cross section as in the above-described embodiment, but forms a plurality of triangular pyramids aligned in a plan view. By having such a structure, the reflecting portion 119 has the reflecting surface 119a facing in four directions and does not form a surface parallel to the light receiving surface 22a. Therefore, the amount of reflected stray light LSR incident on the light receiving portion 22 can be reduced. Can be greatly reduced.

[1-4-2 Modification 2]
FIG. 10 shows the structure of the reflecting portion 219 formed on the inner surface of the case 11 according to the second modification. 10A is a cross-sectional view of the reflecting portion 219, FIG. 10B is a plan view of the reflecting portion 219, and FIG. 10C is a perspective view of the reflecting portion 219 viewed from the light receiving portion 22 side. is there. As shown in the figure, the reflecting portion 219 forms one reflecting surface 219a having a predetermined angle throughout. Even with such a structure, since the reflecting portion 219 does not form a surface parallel to the light receiving surface 22a, the amount of the reflected stray light LSR incident on the light receiving portion 22 can be greatly reduced.

[1-4-3 Modification 3]
FIG. 11 shows the structure of the reflecting portion 319 formed on the inner surface of the case 11 according to the third modification. 11A is a cross-sectional view of the reflecting portion 319, FIG. 11B is a plan view of the reflecting portion 319, and FIG. 11C is a perspective view of the reflecting portion 319 as viewed from the light receiving portion 22 side. is there. As shown in the figure, the reflecting section 319 has a plurality of triangular cross sections, and a plurality of rows of triangular prisms in plan view. Unlike the example shown in FIG. 6, the reflecting portion 319 forms only a plurality of reflecting surfaces 319 a facing one direction. Even with such a structure, since all the reflecting surfaces 319a do not form a surface parallel to the light receiving surface 22a, the amount of the reflected stray light LSR incident on the light receiving unit 22 can be greatly reduced.

[1-4-4 Modification 4]
FIG. 12 shows a structure of a reflection portion 419 formed on the inner surface of the case 11 according to the fourth modification. 12A is a cross-sectional view of the reflecting portion 419, FIG. 12B is a plan view of the reflecting portion 419, and FIG. 12C is a perspective view of the reflecting portion 419 viewed from the light receiving portion 22 side. is there. As shown in the figure, the reflecting portion 419 has a plurality of triangular cross sections as in the third modification, but differs in that it forms a plurality of triangular pyramids aligned in plan view. Since the reflecting portion 419 has such a structure, it forms a plurality of reflecting surfaces 419a facing at least two directions and does not form a surface parallel to the light receiving surface 22a. Therefore, the reflected stray light LSR is incident on the light receiving portion 22. The amount of incident light can be greatly reduced.

[1-5 effects, etc.]
The sensor head 10 of the photoelectric sensor 1 according to the above embodiment includes a light projecting unit 21, a polarizing beam splitter 17, a light receiving unit 22, a reflecting unit 19, and a reflecting surface 19a. The polarization beam splitter 17 is provided on the optical path of the outgoing light LP from the light projecting unit 21, and receives the outgoing light LP and the reflected light LR that forms an optical path coaxial with the outgoing light LP. The light receiving unit 22 includes a light receiving surface 22a that receives the reflected light LR separated from the optical path coaxial with the emitted light by the polarization beam splitter 17. The reflection unit 19 is disposed at a position facing the light receiving surface 22a, and reflects the stray light LS that goes outside the optical path of the emitted light LP. The reflecting surface 19a is formed in the reflecting portion 19, and has a predetermined angle with respect to the light receiving surface 22a so that the reflected stray light LSR travels in the outward direction of the light receiving surface 22a. For this reason, since the amount of the stray light LSR reflected by the reflecting unit 19 entering the light receiving unit 22 can be significantly reduced, the accuracy of object detection by the photoelectric sensor 1 can be improved. Specifically, the amount of reflected stray light LSR entering the light receiving unit 22 can be reduced to about 1/10 (about 0.005% with respect to the laser emission amount) as compared with the conventional case.

Since the reflection part 19 is black, the light component of the stray light LS is absorbed, and the amount of the reflected stray light LSR entering the light receiving part 22 can be more effectively reduced. Therefore, the accuracy of object detection measurement by the photoelectric sensor 1 can be improved.
Moreover, since the reflection part 19 is integrally molded by the case 11, while being easy to manufacture, the manufacturing cost can also be suppressed.

(Other embodiments)
As described above, the embodiments and the modifications thereof have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed.
Therefore, other embodiments will be exemplified below.

[1]
In the said embodiment and modification, the predetermined angle of the reflection part 19 with respect to the light-receiving surface 22a is not limited to around 45 degrees. Any angle that is within a range of less than 90 ° and that reduces the return amount of the stray light LSR to the light receiving unit 22 may be used.
Further, when a plurality of reflecting surfaces 19a are formed in the reflecting portion 19, the predetermined angles with respect to the light receiving surface 22a may be different angles.

[2]
The reflector 19 may be attached to the inner surface of the case 11 separately from the case 11.
The reflection unit 19 may include a polarizing filter instead of or in addition to the above embodiment. In this case, the polarizing filter is, for example, a filter having a polarization component different from that of the outgoing light LP from the light projecting unit 21 (for example, an S-polarized filter if the outgoing light LP is P-polarized light), as in the reflective unit 19 of the above embodiment. To place. Since this polarization filter transmits the light component of the stray light LS, the amount of the reflected stray light LSR can be reduced. As a result, the amount of the reflected stray light LSR entering the light receiving unit 22 can be reduced.

[3]
The reflection surface 19a of the reflection part 19 may be formed on a rough surface. By forming the reflection surface 19a as a rough surface, the stray light LS is diffused, so that the amount of the reflected stray light LSR entering the light receiving unit 22 can be reduced.

[4]
In the above embodiment and the modification, a laser diode is used as the light emitting element 13, but an LED may be used. That is, the wavelength region is not particularly limited as long as it emits light that is recursively reflected by the reflector 30.

As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided.
Accordingly, among the components described in the accompanying drawings and the detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  Moreover, since the above-mentioned embodiment is for demonstrating the technique in this indication, a various change, replacement, addition, abbreviation, etc. can be performed in a claim or its equivalent range.

DESCRIPTION OF SYMBOLS 1 Photoelectric sensor 10 Sensor head 11 Case 13 Light emitting element 14 Light emitting lens 15 Light receiving lens 16 Light receiving element 17 Polarizing beam splitter 18 Light projecting / receiving opening 19 Reflecting part 21 Light projecting part 22 Light receiving part 30 Reflector 40 Cable 50 Amplifier unit S Detection object

Claims (7)

A light projecting unit that emits light;
Provided on the optical path of the outgoing light from the light projecting unit, the outgoing light and the reflected light that is reflected and returned from the outside and forms a coaxial optical path with the outgoing light are incident. Light separation unit,
A light receiving portion having a light receiving surface for receiving the reflected light separated from the light path coaxial with the outgoing light by the light separating portion;
A reflecting portion that is arranged at a position facing the light receiving surface and reflects stray light that goes out of the optical path of the emitted light; and
A reflecting surface formed at the reflecting portion and having a predetermined angle with respect to the light receiving surface so that the reflected stray light travels in an outer direction of the light receiving surface;
A photoelectric sensor head comprising: The reflecting portion is composed of a plurality of the reflecting surfaces.
The photoelectric sensor head according to claim 1. The reflecting portion is composed of a reflecting surface facing two or more directions.
The photoelectric sensor head according to claim 2. The predetermined angle is less than 90 degrees;
The photoelectric sensor head according to claim 1. A case that covers the light projecting unit, the light receiving unit, and the light separating unit;
The reflection part is formed on a part of the case.
The photoelectric sensor head according to claim 1. The light receiving unit includes a light receiving lens and a light receiving element that receives light from the light separating unit through the light receiving lens,
The predetermined angle of the reflecting surface is formed so as to reduce the amount of the reflected stray light incident on the light receiving lens.
The photoelectric sensor head according to claim 1. The stray light is a light component in which a part of the emitted light is directed to the reflecting portion side by the light separating portion.
The photoelectric sensor head according to claim 1.

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