JP6223706B2 - Reflective photoelectric sensor - Google Patents

Description

  The present invention relates to a reflective photoelectric sensor including a light projecting element and a light receiving element.

  Conventionally, the presence or absence of the reflected light of the light projected from the light projecting element to the detection area and the intensity of the reflected light are detected by the light receiving element to determine whether or not the detection target exists in the detection area. A reflection type photoelectric sensor for detection is known. As such a reflection type photoelectric sensor, as shown in FIG. 8, along a light path used for detection, a light projecting element 91, a light projecting lens 92, a mirror 93, a light receiving lens 94, and a light receiving element 95 are provided. There is a reflection type photoelectric sensor 90 provided with (for example, Patent Document 1).

JP 2004-28598 A

  By the way, the above-described reflective photoelectric sensor 90 further includes a lens barrel 96 (light projection guide) penetrating the mirror 93 along the optical axis of the light projecting element 91. Therefore, when detecting the detection object TG, a part of the light deflected by the mirror 93 out of the light indicated by the two-dot chain arrow in FIG. 8 is shown in the barrel 96 as indicated by the broken arrow in FIG. As a result, the amount of light that can be received by the light receiving element 95 is reduced. In this case, the detection performance of the reflective photoelectric sensor 90 may be reduced due to a decrease in the amount of light received by the light receiving element 95.

  The present invention has been made in view of such problems. An object of the present invention is to provide a reflective photoelectric sensor that can suppress a decrease in the amount of light received by a light receiving element among the light reflected by a detection target.

A reflective photoelectric sensor that solves the above problems includes a light projecting element capable of projecting light onto a detected object, a mirror capable of deflecting light reflected from the detected object, and an optical axis of the light projecting element. A lens barrel penetrating the mirror along the same optical axis, a light receiving element capable of receiving light deflected by the mirror, and a transparent plate disposed in front of the lens barrel. The light projected from the light projecting element through the transparent plate is reflected from the detected object, passes through the transparent plate, is deflected by the mirror, and is received by the light receiving element . Furthermore, in the same reflective photoelectric sensor, the distance from the light receiving surface to the axial center of the barrel is longer than the distance from the light receiving surface to the center of the mirror in the direction orthogonal to the light receiving surface of the light receiving element. In other words, the area of the mirror on the light receiving element side is larger than that of the lens barrel .

  According to the above configuration, the light projected from the light projecting element is reflected from the detected body when the detected body is present. The light reflected by the detection object is deflected by the mirror and then received by the light receiving element. Thus, the reflective photoelectric sensor detects the presence / absence of the detected object based on whether or not the reflected light reflected from the detected object is received by the light receiving element. In the above configuration, in the direction orthogonal to the light receiving surface of the light receiving element, the distance from the light receiving surface to the axial center of the lens barrel is longer than the distance from the light receiving surface to the center of the mirror. For this reason, for example, in the same direction, there is the following difference compared to the case where the distance from the light receiving surface to the center of the lens barrel is equal to the distance from the light receiving surface to the center of the mirror. That is, in the above configuration, the area of the mirror capable of deflecting light on the light receiving element side with respect to the lens barrel can be increased in the direction orthogonal to the light receiving surface of the light receiving element. In other words, in the same direction, the area of the mirror that is blocked by the lens barrel on the opposite side of the light receiving element from the lens barrel can be reduced. Accordingly, it is possible to suppress a reduction in the amount of light received by the light receiving element among the light reflected by the detection target.

  The reflective photoelectric sensor further includes a mirror holding portion that holds the mirror, and the lens barrel has an end opposite to the light receiving element side end of the lens barrel in a direction orthogonal to the light receiving surface. It is desirable that the portion is made to penetrate the mirror holding portion so that the portion matches the end of the mirror holding portion opposite to the end on the light receiving element side.

  According to the above configuration, in the direction orthogonal to the light receiving surface, the end of the barrel opposite to the end of the light receiving lens, and the end of the mirror holding portion opposite to the end of the light receiving lens No mirror is placed between the two. For this reason, even if light is deflected, the area of the mirror that is blocked by the lens barrel can be further reduced. Therefore, it is possible to further suppress a reduction in the amount of light received by the light receiving element among the light reflected by the detection target.

  The reflective photoelectric sensor further includes a light projecting lens that collects light projected from the light projecting element, and the light projecting lens is arranged on the detected object side in a direction along the optical axis of the light projecting element. Preferably, the light projecting element is provided inside the base end side of the lens barrel in a direction along the optical axis of the light projecting element.

  According to the above configuration, compared to the case where the light projecting element and the light projecting lens are provided on the base end side of the lens barrel, the light projecting element and the light projecting lens are disposed at a short distance in the direction along the optical axis of the light projecting element. Can fit inside. For this reason, it is possible to reduce the size of the reflective photoelectric sensor in the direction along the optical axis of the light projecting element.

  According to the above reflection type photoelectric sensor, it is possible to suppress a reduction in the amount of reflected light of the light projected on the detection object.

The perspective view of a reflection type photoelectric sensor. The perspective view which shows the internal structure of a reflection type photoelectric sensor. Sectional drawing which shows the arbitrary cross sections in the left-right direction of a reflective photoelectric sensor. The perspective view which shows the internal structure of a reflection type photoelectric sensor. (A), (b) is a front view which shows the internal structure of a reflection type photoelectric sensor. The sectional side view which shows the effect | action of a reflection type photoelectric sensor typically. FIG. 5 is a front sectional view schematically showing the operation of the reflective photoelectric sensor. The schematic diagram which shows schematic structure of the conventional reflective photoelectric sensor.

Hereinafter, an embodiment of a reflective photoelectric sensor will be described with reference to the drawings.
As shown in FIG. 1, the reflective photoelectric sensor 10 is a transparent plate that covers an outer casing 11 that has a rectangular box shape that is long in the vertical direction, and an opening 12 that is formed in a rectangular shape in the upper portion of the narrow and vertically long front surface of the outer casing 11. 13. The reflective photoelectric sensor 10 includes an indicator lamp 14 that protrudes from the upper end surface of the exterior 11 and a power supply unit 15 that supplies power. Support holes 16 and 17 through which fixing members such as bolts are inserted when the reflective photoelectric sensor 10 is installed are formed through the left and right sides of the exterior 11. The support holes 16, 17 are formed on the left and right side surfaces of the exterior 11 on the front lower side and the rear upper side that is the diagonal of the front lower side. The indicator lamp 14 can be lit in different lighting modes depending on the case, for example, when the detected object TG (see FIG. 6) is detected in the detection region or when nothing is detected. In this embodiment, in FIG. 1, the longitudinal direction of the exterior 11 of the reflective photoelectric sensor 10 is the vertical direction Z, the penetration direction of the support holes 16 and 17 with respect to the exterior 11 is the left-right direction X, and the left-right direction X A direction perpendicular to the vertical direction Z is defined as a front-rear direction Y.

  As shown in FIG. 2, the reflection photoelectric sensor 10 receives therein a light projecting unit 20 for projecting light toward the detection object TG and light reflected by the detection object TG. And a light receiving unit 40.

  As shown in FIG. 3, the light projecting unit 20 includes a light projecting element 21 that can project light onto the detection target TG, and a light projecting lens 22 that condenses the light projected from the light projecting element 21. I have. As shown in FIG. 2, the light projecting unit 20 includes a relay board 23 on which the light projecting element 21 is directly mounted, a light projecting board 24 connected to the relay board 23, the light projecting element 21, and the light projecting element. And a light projection guide portion 25 for supporting the lens 22 therein. Here, a two-dot chain line passing through the center of the light projecting element 21 shown in FIG. 3 indicates the optical axis P <b> 1 of the light projecting element 21. Hereinafter, the direction in which the optical axis P <b> 1 of the light projecting element 21 extends is also referred to as the optical axis direction of the light projecting element 21. In the present embodiment, the optical axis direction of the light projecting element 21 coincides with the front-rear direction Y. 3 shows a cross section in the left-right direction X including the optical axis P1 of the light projecting element 21 in the reflective photoelectric sensor 10 shown in FIG.

  As shown in FIG. 2, the light projecting board 24 has a connection terminal 26 a that can be electrically connected to the power supply unit 15 on its lower end side, and a connection terminal 26 b that can be electrically connected to the relay board 23 on its upper end side. have. The light projecting substrate 24 is formed in a thin plate shape extending along the front-rear direction Y and the vertical direction Z. A quarter-arc notch 24a corresponding to the support hole 16 of the exterior 11 is formed on one end side (lower right side in FIG. 2) of the light projecting substrate 24, and the other end side (upper left in FIG. 2). A semicircular arc-shaped notch 24 b corresponding to the support hole 17 of the exterior 11 is formed on the side). The light projecting board 24 is a circuit board that controls the light emission of the light projecting element 21.

  As shown in FIG. 2, the relay board 23 includes a first extending portion 27 extending along the front-rear direction Y and the up-down direction Z, and a second extending portion 28 extending along the left-right direction X and the up-down direction Z. ing. That is, in the relay substrate 23, the first extending portion 27 and the second extending portion 28 are orthogonal to each other so as to form a substantially T shape in plan view from above. As shown in FIG. 2, a connection terminal 29 a that can be electrically connected to the light projecting substrate 24 is formed in the first extending portion 27, and as shown in FIG. 3, the second extending portion 28 has a light projecting portion. A connection terminal 29b that can be electrically connected to the element 21 is formed. With such a relay substrate 23, the optical axis direction of the light projecting element 21 (the front-rear direction Y in the present embodiment) is different from the direction orthogonal to the light projecting substrate 24 (the left-right direction X in the present embodiment). The light projecting element 21 can be electrically connected (mounted) to the light projecting substrate 24.

  As shown in FIGS. 2 and 3, the light projection guide unit 25 includes a mirror 31 that deflects reflected light of the light projected on the detection target TG, a mirror holding unit 32 that holds the mirror 31, and a light projection. And a lens barrel 33 extending along the optical axis P1 so as to surround the optical axis P1 of the element 21. Here, in the light projecting guide portion 25, the side on which light travels along the optical axis P1 of the light projecting element 21 is referred to as a distal end side, and the opposite side is also referred to as a proximal end side. The mirror holding portion 32 is provided so that the surface on the tip side intersects the optical axis direction (front-rear direction Y) of the light projecting element 21 so as to intersect the lens barrel 33. Further, the mirror 31 is held by the mirror holding unit 32 so that the reflected light reflected from the detection target TG can be deflected toward the light receiving unit 40.

  As shown in FIG. 2, the outer shape of the lens barrel 33 when viewed from the front-rear direction Y is substantially U-shaped when viewed from the front, and the mirror holding portion 32 is provided along the optical axis P <b> 1 of the light projecting element 21. doing. The axial center position of the lens barrel 33 when the lens barrel 33 penetrates the mirror holding portion 32 is a position above the center position of the mirror holding portion 32 in the vertical direction Z. In the present embodiment, the upper end of the lens barrel 33 and the upper end of the mirror holding portion 32 are coincident with each other. That is, in the vertical direction Z, the end portion 33b of the lens barrel 33 opposite to the end portion 33a on the light receiving portion 40 side is the end portion 32b of the mirror holding portion 32 opposite to the end portion 32a on the light receiving portion 40 side. Is consistent with 2, the width dimension of the lens barrel 33 is shorter than the width dimension of the mirror holding portion 32 in the left-right direction X, and the lens barrel 33 is positioned at the center of the mirror holding portion 32 in the left-right direction X. doing. As shown in FIG. 3, a through hole 34 is formed through the lens barrel 33 along the optical axis P <b> 1 of the light projecting element 21. In the present embodiment, the axis center of the lens barrel 33 is the axis center of the through hole 34 and coincides with the optical axis P1 of the light projecting element 21.

  As shown in FIG. 3, the through hole 34 of the lens barrel 33 has a first diameter portion 34a and a second diameter portion 34b having an inner diameter smaller than the first diameter portion 34a from the proximal end side toward the distal end side. A third diameter portion 34c having a smaller inner diameter than the first diameter portion 34a and a larger inner diameter than the second diameter portion 34b is formed. The light projecting element 21 is inserted into the first diameter portion 34 a on the proximal end side of the through hole 34, and the light projecting lens 22 is inserted into the third diameter portion 34 c on the distal end side of the through hole 34. . The second diameter portion 34 b of the through hole 34 is formed in a flange shape in the through hole 34, and is provided to block light greatly deviated from the optical axis among the light projected from the light projecting lens 22. . A cylindrical lens cover 35 having an inner diameter smaller than that of the third diameter portion 34c is attached to the tip of the through hole 34. The lens cover 35 is formed of a material that does not transmit light. Further, the lens cover 35 has an arrangement mode in which the lens cover 35 protrudes from the light projection guide portion 25 toward the front end side in the optical axis direction (front-rear direction Y) of the light projecting element 21. It abuts on the transparent plate 13 covering.

  As shown in FIG. 3 and FIG. 4, the light receiving unit 40 collects the light deflected by the mirror 31 of the light projecting unit 20 and receives light that can receive the light collected by the light receiving lens 41. An element 42 and a light receiving substrate 43 on which the light receiving element 42 is mounted are provided. In addition, the light receiving unit 40 includes a shield plate 44 as an example of a covering member.

  As shown in FIG. 4, the light receiving lens 41 is chamfered so that both end portions in the left-right direction X are surfaces orthogonal to the left-right direction X, while both end portions in the front-rear direction Y are the same front-rear direction Y. It is chamfered to be orthogonal. The light receiving lens 41 has engaging portions 45 that are formed to protrude in a rectangular shape toward the outside of the light receiving lens 41 at both ends in the front-rear direction Y. The light receiving lens 41 is disposed between the light projecting guide portion 25 and the light receiving element 42 in the vertical direction Z by engaging the engaging portion 45 inside the exterior 11. Here, a two-dot chain line passing through the center of the light receiving lens 41 shown in FIG. 3 indicates the optical axis P <b> 2 of the light receiving lens 41. For this reason, in this embodiment, the up-down direction Z is the optical axis direction of the light receiving lens 41.

  As shown in FIG. 3, the light receiving substrate 43 includes a connection terminal 47 a that can be electrically connected to the power supply unit 15 and a connection terminal 47 b that can be electrically connected to the light receiving element 42. In addition, the light receiving substrate 43 is formed in a thin plate shape that extends along the front-rear direction Y and the up-down direction Z, similarly to the light projecting substrate 24. A quarter-arc notch 48a corresponding to the support hole 16 of the exterior 11 is formed on one end side (lower right side in FIG. 3) of the light receiving substrate 43, and the other end side (upper left side in FIG. 3) of the light receiving substrate 43. A quarter-arc notch 48 b corresponding to the support hole 17 of the exterior 11 is formed.

  The connection terminal 47 b connected to the light receiving element 42 is provided in the vicinity of the notch 48 a formed on one end side of the light receiving substrate 43. The light receiving substrate 43 is a circuit substrate that can determine whether or not the detection object TG is present in the detection region according to the amount of light received by the light receiving element 42. Further, the light receiving substrate 43 is disposed so as to face the light projecting substrate 24 with an interval in the left-right direction X. At this time, the connection terminal 47b of the light receiving substrate 43 faces the light projecting substrate 24, and the connection terminal 47a of the light receiving substrate 43 is provided outside.

  As shown in FIGS. 3 and 4, the light receiving element 42 includes a base 51 having a substantially rectangular plate shape, a light receiving chip 52 provided on the base 51, and a protection covering the light receiving chip 52 and the base 51 from above. And a cover 53. When the light receiving element 42 is mounted on the light receiving substrate 43, the base 51 is in contact with the connection terminal 47 b of the light receiving substrate 43 and is supported at one end by the light receiving substrate 43. The light receiving chip 52 has a rectangular plate shape and is slightly smaller than the base 51. The light receiving chip 52 can detect whether light is received or can detect the amount of light received.

  As shown in FIG. 5A, the light receiving chip 52 is arranged on the base 51 in a state where the center position in the left-right direction X is different from the center position of the light receiving element 42. That is, in the left-right direction X, the center position of the light receiving chip 52 is a distance from the center position of the light receiving element 42 to the side opposite to the side where the light receiving element 42 is mounted on the light receiving substrate 43 (that is, the light projecting substrate 24 side). Offset by L1. Furthermore, in the present embodiment, the center position of the light receiving chip 52 in the direction orthogonal to the optical axis P <b> 2 of the light receiving lens 41 (left-right direction X) in a state where the light receiving element 42 is mounted on the light receiving substrate 43. It is located on an extension line of the optical axis P2. That is, the distance L1 is set so that the center position of the light receiving chip 52 is positioned on the extension line of the optical axis P2 of the light receiving lens 41. In the present embodiment, the center position of the light receiving chip 52 is also an intermediate position between the light projecting substrate 24 and the light receiving substrate 43 in the direction in which the light projecting substrate 24 and the light receiving substrate 43 face each other (left-right direction X). Yes. As shown in FIG. 3, the center position of the light receiving chip 52 in the front-rear direction Y coincides with the center position of the light receiving element 42 in the front-rear direction Y, and is also on the extended line of the optical axis P <b> 2 of the light receiving lens 41. . For this reason, the center position of the light receiving chip 52 is located on an extension line of the optical axis P <b> 2 of the light receiving lens 41 in the left-right direction X and the front-rear direction Y that are orthogonal to the optical axis P <b> 2 of the light receiving lens 41.

  As shown in FIGS. 3 and 4, the protective cover 53 has a rectangular plate shape substantially the same as the base 51, and is fixed to the base 51 with the light receiving chip 52 covered from above. The protective cover 53 is formed of a transparent resin, and can transmit light condensed by the light receiving lens 41. The protective cover 53 is provided for the purpose of protecting the light receiving chip 52 so that an object does not directly contact the light receiving chip 52. Further, the surface of the light receiving element 42 (protective cover 53) that faces the light receiving lens 41 is a light receiving surface 42a on which the light condensed by the light receiving lens 41 strikes. In the present embodiment, the direction orthogonal to the light receiving surface 42 a is the direction along the optical axis P <b> 2 of the light receiving lens 41 and is the vertical direction Z.

  Thus, in the light receiving element 42, the light receiving surface 42a intersects with the optical axis P2 of the light receiving lens 41 (in the present embodiment, orthogonal), and the light receiving surface 42a intersects with the light projecting substrate 24 (in the present embodiment, orthogonal). It is mounted on the light receiving substrate 43.

  As shown in FIGS. 4 and 5B, the shield plate 44 is formed in a box shape by bending a metal plate material. As shown in FIG. 5B, engaging surfaces 46 extending in the direction perpendicular to the vertical direction Z are formed at the upper and lower ends of the shield plate 44. The shield plate 44 is mounted on the light receiving substrate 43 by sandwiching the upper and lower surfaces of the light receiving substrate 43 on which the light receiving element 42 is mounted from the vertical direction Z by the engaging surface 46. As shown in FIG. 2, when the shield plate 44 is mounted on the light receiving substrate 43, an opening 44 a having a substantially rectangular shape is formed on the surface where the shield plate 44 faces the light receiving lens 41. The size of the opening 44 a is substantially the same as the light receiving surface 42 a of the light receiving element 42, and is provided so that the light collected by the light receiving lens 41 can be received by the light receiving element 42. In addition, when the shield plate 44 is attached to the light receiving substrate 43, the shield plate 44 can shield the light receiving element 42 from the light projecting substrate 24.

  5A, when the light receiving element 42 is mounted on the light receiving substrate 43, the light projecting substrate 24 is arranged in the direction in which the light projecting substrate 24 and the light receiving substrate 43 face each other (left-right direction X). And the light receiving element 42 is provided with a gap L2. As shown in FIG. 5B, the shield plate 44 is mounted on the light receiving substrate 43 so as to pass through the gap L2. In this way, since the light receiving element 42 does not come into direct contact with the light projecting substrate 24, noise generated from the light projecting substrate 24 due to driving of the light projecting element 21 is suppressed from being transmitted to the light receiving element 42. Furthermore, since the shield plate 44 covers the light receiving element 42, noise generated from the light projecting substrate 24 as the light projecting element 21 is driven is suppressed from being transmitted to the light receiving element 42 and the light receiving substrate 43. That is, the shield plate 44 is provided to protect the circuit components of the light receiving element 42 and the light receiving unit 40 from noise.

Next, the operation of the reflective photoelectric sensor 10 of this embodiment will be described.
As shown in FIG. 6, when detecting whether or not the detection object TG exists in the detection area, first, from the light projecting element 21 to the detection area via the light projection lens 22 and the transparent plate 13. Light is projected. When the detection object TG is not present in the detection area, the projected light is not reflected, so that the amount of light received by the light receiving element 42 is “0 (zero)” or very small. Then, it is detected that the detection object TG does not exist in the detection region according to the amount of received light.

  On the other hand, as shown in FIG. 6, when the detection object TG is present in the detection region, the light projected from the light projecting element 21 is reflected toward the reflective photoelectric sensor 10 by hitting the detection object TG. The Then, a part of the reflected light passes through the transparent plate 13 and strikes the mirror 31 of the light projection guide portion 25, thereby being deflected to the light receiving lens 41 side. Then, the light deflected by the mirror 31 is collected by the light receiving lens 41 and hits the light receiving chip 52 of the light receiving element 42, thereby detecting a light amount of a certain amount or more. Thus, it is detected that the detection object TG is present in the detection region according to the amount of received light.

  Here, as shown in FIG. 5A, in the optical axis direction (vertical direction Z) of the light receiving lens 41, the distance L3 from the light receiving surface 42a of the light receiving element 42 to the axial center of the lens barrel 33 is the light receiving element 42. Is longer than the distance L4 from the light receiving surface 42a to the center position of the mirror 31. That is, in the light projection guide portion 25, the axis center of the lens barrel 33 is located above the center position of the mirror 31. Therefore, as shown in FIG. 6, for example, when the axial center of the lens barrel 33 is located at the center position of the mirror 31 in a cross-sectional view including the central axis of the lens barrel 33 and orthogonal to the left-right direction X. In comparison, much of the light reflected by the detection object TG can be deflected to the light receiving lens 41. Thus, the detection performance of the light receiving element 42 can be enhanced by increasing the amount of light received by the light receiving chip 52. Here, the center position of the mirror 31 means an intermediate position between one end (uppermost end) of the mirror 31 and the other end (lowermost end) of the mirror 31 in the optical axis direction (vertical direction) of the light receiving lens 41. doing.

  In addition, as shown in FIG. 7, the center position of the light receiving chip 52 is offset by a distance L1 with respect to the center position of the light receiving element 42 in the direction in which the light projecting substrate 24 and the light receiving substrate 43 are opposed (left-right direction X). Thus, the light receiving lens 41 is positioned on an extension line of the optical axis P2. Therefore, as shown by a two-dot chain line in FIG. 7, it is possible to place the center of the light receiving chip 52 at a place where the light deflected by the mirror 31 is collected by the light receiving lens 41. Therefore, the detection performance of the light receiving element 42 can be improved by increasing the amount of light received by the light receiving chip 52.

According to the above embodiment, the following effects can be obtained.
(1) The light receiving element 42 is mounted on the light receiving substrate 43 such that the light receiving surface 42a is orthogonal to the optical axis P2 of the light receiving lens 41 and the light receiving surface 42a is orthogonal to the light receiving substrate 43. Therefore, for example, by mounting the light receiving element 42 on another substrate other than the light receiving substrate 43 and connecting the other substrate so as to be orthogonal to the light receiving substrate 43, the light receiving surface 42 a is light of the light receiving lens 41. Compared with the case where the light receiving element 42 is arranged so as to be orthogonal to the axis P2, the following points are different. That is, it is not necessary to newly provide such another substrate, and the reflective photoelectric sensor 10 can be reduced in size by not providing such another substrate.

  (2) Since the gap L <b> 2 is provided between the light projecting substrate 24 and the light receiving element 42, even if noise is generated in the light projecting substrate 24 by driving the light projecting element 21, the noise is received by the light receiving element 42. The influence which it has on can be suppressed.

  (3) The center position of the light receiving chip 52 in the direction (left-right direction X) orthogonal to the optical axis P2 of the light receiving lens 41 is set to a position different from the center position of the light receiving element 42. For this reason, the position of the light receiving chip 52 with respect to the light receiving element 42 can be set to the light projecting substrate 24 side or the light receiving substrate 43 side. Therefore, even if the position where the light is collected changes according to the arrangement mode of the light receiving lens 41, the light receiving element 42 is replaced with another light receiving element 42 in which the position of the light receiving chip 52 is different. It can be easily handled.

  (4) Since the light receiving chip 52 is positioned on the extension line of the optical axis P <b> 2 of the light receiving lens 41, the light collected by the light receiving lens 41 can be received on the light receiving chip 52. For this reason, it is possible to suppress the amount of light received by the light receiving chip 52 from being increased and the detection performance of the light receiving element 42 from being deteriorated.

  (5) Since the center position of the light receiving chip 52 is located on the extended line of the optical axis P2 of the light receiving lens 41 in the direction orthogonal to the optical axis P2 of the light receiving lens 41, most of the light collected by the light receiving lens 41 is received. Light can be received at the center of the chip 52. For this reason, the detection performance of the light receiving element 42 can be improved.

  (6) Since the shield plate 44 is disposed in the gap L <b> 2 between the light receiving element 42 and the light projecting substrate 24, even if noise is generated in the light projecting substrate 24 by driving the light projecting element 21, the same noise is generated. Can further suppress the influence of the light receiving element 42.

  (7) In a direction (vertical direction Z) orthogonal to the light receiving surface 42a of the light receiving element 42, the distance L3 from the light receiving surface 42a to the axial center of the lens barrel 33 is greater than the distance L4 from the light receiving surface 42a to the center of the mirror 31. Is also far away. Therefore, for example, in the same direction, when the distance L3 from the light receiving surface 42a to the axis center of the lens barrel 33 is equal to the distance L4 from the light receiving surface 42a to the center of the mirror, that is, the axis center of the lens barrel 33 and the mirror Compared to the case where the centers of 31 coincide, there are the following differences. In other words, in the above-described embodiment, the area of the mirror 31 that can deflect light is larger on the light receiving element 42 side than the lens barrel 33 in the direction (vertical direction Z) orthogonal to the light receiving surface 42a of the light receiving element 42. it can. In other words, in the same vertical direction Z, the area of the mirror 31 that is blocked by the lens barrel 33 even when the light is deflected can be narrowed on the opposite side of the light receiving element 42 from the lens barrel 33. Accordingly, in the light receiving element 42, it is possible to suppress a reduction in the amount of reflected light of the light projected on the detection object TG.

  (8) In the direction (vertical direction Z) orthogonal to the light receiving surface 42a of the light receiving element 42, the end portion 33b of the lens barrel 33 and the end portion 32b of the mirror holding portion 32 coincide with each other, and therefore the end portion 32b. , 33b, the mirror 31 is not disposed. For this reason, even if light is deflected, the area of the mirror 31 that is blocked by the lens barrel 33 can be further reduced. Therefore, in the light receiving element 42, it is possible to further suppress a decrease in the amount of received reflected light of the light projected on the detection object TG.

  (9) In the lens barrel 33 of the light projecting guide portion 25, the light projecting element 21 is provided on the base end side, and the light projecting lens 22 is provided on the front end side. For this reason, compared with the case where the light projecting element 21 and the light projecting lens 22 are provided on the base end side of the lens barrel 33 of the light projecting guide part 25, the reflection type is more effective in the optical axis direction (front-rear direction Y) of the light projecting element 21. The photoelectric sensor 10 can be reduced in size.

  (10) When the focal length of the light receiving lens 41 is changed by changing the size or shape of the light receiving lens 41, the light receiving element 42 with respect to the light receiving substrate 43 in the optical axis direction (vertical direction Z) of the light receiving lens 41 is changed. The mounting position may be changed. For example, when the focal length is increased by increasing the size of the light receiving lens 41 in order to improve the performance of the reflective photoelectric sensor 10, the mounting position of the light receiving element 42 with respect to the light receiving substrate 43 is simply moved downward. Yes. In this way, the design flexibility with respect to the specification change of the light receiving lens 41 can be ensured.

  (11) The lens cover 35 provided at the tip of the lens barrel 33 protruding from the mirror 31 in the optical axis direction of the light projecting element 21 is in contact with the transparent plate 13. For this reason, it is possible to suppress the light irradiated from the light projecting element 21 to the detection target TG from being reflected by the transparent plate 13, and the reflected light being deflected by the mirror 31 and received by the light receiving element 42. That is, it is possible to suppress the detection accuracy of the reflective photoelectric sensor 10 from being lowered by receiving the light that is not the light reflected by the detection target TG with the light receiving element 42.

In addition, you may change the said embodiment as shown below.
The light receiving chip 52 does not have to be offset with respect to the light receiving element 42 in the left-right direction X. In this case, the light receiving chip 52 may be offset from the light receiving element 42 in the front-rear direction Y. In addition, the light receiving chip 52 may be offset from the light receiving element 42 in the left-right direction X and the front-rear direction Y. In any case, it is desirable that the light receiving element 42 be positioned on an extension line of the optical axis P2 of the light receiving lens 41. Further, it is more desirable that the light receiving chip 52 of the light receiving element 42 is located on an extension line of the optical axis P <b> 2 of the light receiving lens 41.

  The light receiving element 42 does not necessarily have to be mounted on the light receiving substrate 43 so as to be orthogonal as long as the light receiving surface 42a intersects the optical axis P2 of the light receiving lens 41. Further, the light receiving element 42 does not necessarily have to be mounted on the light receiving substrate 43 so as to be orthogonal as long as the light receiving surface 42 a intersects the light projecting substrate 24.

  The center position of the light receiving chip 52 in the direction orthogonal to the optical axis P2 of the light receiving lens 41 (left-right direction X) may not be located on the extension line of the optical axis P2 of the light receiving lens 41. In this case, at least the light receiving chip 52 only needs to be positioned on the extension line of the optical axis P <b> 2 of the light receiving lens 41.

  The reflective photoelectric sensor 10 does not have to have the optical axis P2 of the light receiving lens 41 in the vertical direction Z. For example, the optical axis P2 of the light receiving lens 41 may be the left-right direction X, the front-rear direction Y, or another direction.

  The shield plate 44 may not be provided, and the gap L2 between the light projecting substrate 24 and the light receiving element 42 may not be provided. In this case, the light receiving element 42 may be mounted on the light receiving substrate 43 with both ends supported by the light projecting substrate 24 and the light receiving substrate 43.

In the through-hole 34 of the lens barrel 33, the light projecting element 21 and the light projecting lens 22 may be disposed on the distal end side or on the proximal end side.
The center position of the mirror 31 serving as a reference for the distance L4 may be the center of gravity position on the surface where the light of the mirror 31 can be deflected.

  DESCRIPTION OF SYMBOLS 10 ... Reflection type photoelectric sensor, 20 ... Projection part, 21 ... Projection element, 22 ... Projection lens, 24 ... Projection board, 25 ... Projection guide part, 31 ... Mirror, 32 ... Mirror holding part, 32a, 32b ... end, 33 ... lens barrel, 33a, 33b ... end, 40 ... light receiving part, 41 ... light receiving lens, 42 ... light receiving element, 42a ... light receiving surface, 43 ... light receiving substrate, 44 ... shield plate (of shielding part) (Example), 52... Light receiving chip, L 2 .. clearance, L 3, L 4... Distance, P 1 .. optical axis of light projecting element, P 2 .. optical axis of light receiving lens, TG.

Claims (3)

A light projecting element capable of projecting light on the detection object;
A mirror capable of deflecting light reflected from the detected object;
A lens barrel penetrating the mirror along the optical axis so as to surround the optical axis of the light projecting element;
A light receiving element capable of receiving light deflected by the mirror;
A transparent plate disposed in front of the lens barrel ,
A reflective photoelectric sensor in which light projected from the light projecting element through the transparent plate is reflected from the detected object, passes through the transparent plate, is deflected by the mirror, and is received by the light receiving element; There,
In the direction orthogonal to the light receiving surface of the light receiving element, the distance from the light receiving surface to the center of the lens barrel is longer than the distance from the light receiving surface to the center of the mirror, and the distance from the lens barrel A reflective photoelectric sensor characterized in that the area of the mirror on the light receiving element side is increased . A mirror holding part for holding the mirror;
In the direction perpendicular to the light receiving surface, the lens barrel has an end opposite to the end on the light receiving element side of the lens barrel opposite to the end on the light receiving element side of the mirror holding portion. The reflective photoelectric sensor according to claim 1, wherein the reflective photoelectric sensor is provided so as to penetrate the mirror holding portion so as to coincide with the end portion of the mirror. A light projection lens for collecting the light projected from the light projecting element;
The light projecting lens is provided inside the distal end side of the lens barrel which is the detected object side in a direction along the optical axis of the light projecting element,
The reflective photoelectric sensor according to claim 1, wherein the light projecting element is provided inside a base end side of the lens barrel in a direction along an optical axis of the light projecting element. .