JP2019016624A - Photo interrupter and proximity sensor including the same - Google Patents

Abstract

To provide a photo interrupter and a proximity sensor including the same capable of enhancing accuracy of detecting light reflected from a detection object.SOLUTION: A photo interrupter includes a light emitting portion for emitting light, a light receiving portion for detecting reflected light of light with which a detection target is irradiated, a substrate on which the light emitting portion and the light receiving portion are arranged, and a first light shielding wall provided between the light emitting portion and the light receiving portion and provided on the substrate, and a cover. The cover is provided so as to face the substrate. The cover includes a first light transmitting member so as to face the light emitting portion, a second light transmitting member so as to face the light receiving portion, and a second light shielding wall provided between the first light transmitting member and the second light transmitting member.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a photo interrupter and a proximity sensor including the photo interrupter.

  The proximity sensor detects the distance from the detection target based on the intensity of light detected by the photo interrupter. Photo interrupters include a reflective photo interrupter including a light emitting unit that emits light and a light receiving unit that detects light reflected from a detection target. For example, Patent Document 1 describes an example of a photo interrupter. The photointerrupter described in Patent Document 1 includes a light source that emits light, a light receiving element that detects light reflected from a detection target, a substrate on which the light source and the light receiving element are mounted, and a partition wall that partitions the light source and the light receiving element. And comprising.

Japanese Patent Application Laid-Open No. 2006-149541

  Here, the photo interrupter is desired to improve the accuracy of detecting the light reflected from the detection target.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a photo interrupter capable of increasing the accuracy of detecting light reflected from a detection target and a proximity sensor including the photo interrupter. .

  In order to achieve the above object, a photo interrupter of one embodiment of the present invention includes a light emitting unit that irradiates light, a light receiving unit that detects reflected light of the light irradiated on a detection target, the light emitting unit, and the light emitting unit. A first light shielding wall provided on the substrate between the light emitting unit and the light receiving unit, a first light transmissive member facing the light emitting unit, and the light receiving unit. And a second light-transmitting member facing the substrate, and a second light-shielding wall provided between the first light-transmitting member and the second light-transmitting member, and a cover provided facing the substrate With.

  Thereby, it can suppress detecting light other than the reflected light which the light emission part reflected with the detection target object. As a result, the photo interrupter can improve the accuracy of detecting the light reflected from the detection target.

  As a desirable mode of the photo interrupter, it is preferable that the first light shielding wall and the second light shielding wall are in contact with each other in a direction perpendicular to the surface of the substrate.

  According to this, the light incident on and reflected by the first light transmissive member is blocked by the first light shielding wall and the second light shielding wall. Thereby, it can further suppress that light-emitting part detects light other than the reflected light reflected by the detection target.

  As a desirable mode of the photo interrupter, it is preferable that the cover includes a frame member having a pair of openings into which the first light transmitting member and the second light transmitting member are fitted and fixed.

  According to this, a 2nd light-shielding wall is arrange | positioned between a 1st translucent member and a 2nd translucent member by fitting a 1st translucent member and a 2nd translucent member. As a result, the second light shielding wall is appropriately positioned between the first light transmissive member and the second light transmissive member.

  As a desirable mode of the photo interrupter, the second light transmitting member is preferably an optical filter that reduces disturbance light.

  According to this, the disturbance light incident on the light receiving unit can be suppressed. Thereby, it can suppress detecting light other than the reflected light which the light-receiving part reflected by the detection target object.

  As a desirable mode of the photo interrupter, the first light transmissive member is preferably an optical filter that reduces disturbance light.

  According to this, the influence of disturbance light can be suppressed. Thereby, it can suppress detecting light other than the reflected light which the light emission part reflected with the detection target object.

  As a desirable mode of the photo interrupter, the first light transmissive member is preferably made of glass or resin. According to this, the cost of the photo interrupter can be reduced.

  As a desirable mode of the photo interrupter, the cover is preferably made of a heat conductive resin or aluminum.

  According to this, the heat generated in the light emitting part can be efficiently radiated. As a result, the element lifetime of the light emitting part or the light receiving part can be extended.

  According to this, the heat generated in the light emitting part can be efficiently radiated. Thereby, the temperature of the light emitting part and the light receiving part can be kept low. As a result, the element lifetime of the light emitting part and the light receiving part can be extended.

  A proximity sensor according to one aspect of the present invention includes a plurality of the above-described photointerrupters, and a microprocessor that calculates a distance from the photointerrupter to the detection object based on a detection signal detected by the photointerrupter. Prepare.

  According to this, the microprocessor can calculate the distance between the photo interrupter and the detection target object based on the detection signal obtained by detecting the detection target object with high accuracy. As a result, the proximity sensor can increase the calculation accuracy of the distance from the detection target.

  ADVANTAGE OF THE INVENTION According to this invention, the photo interrupter which can improve the precision which detects the light reflected from a detection target object, and a proximity sensor provided with this can be provided.

FIG. 1 is a schematic diagram illustrating an example of the proximity sensor of this embodiment. FIG. 2 is a perspective view showing an example of the photo interrupter of the present embodiment. FIG. 3 is an exploded perspective view showing an example of the photo interrupter of the present embodiment. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a bottom view showing an example of the cover of the present embodiment. FIG. 6 is a schematic cross-sectional view illustrating a state in which light emitted from the light emitting unit of the photo interrupter of the comparative example is reflected by the light transmissive member.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Proximity sensor)
FIG. 1 is a schematic diagram illustrating an example of the proximity sensor of this embodiment. The proximity sensor 1 is assembled to a robot arm, for example. The proximity sensor 1 is, for example, a sensor that detects a detection object that has approached the robot arm and notifies the robot control unit of the approach of the detection object. The proximity sensor 1 includes a first substrate group 10, a second substrate 12, and a cable 13. The first substrate group 10 includes first substrates 14, 16, and 18. Note that the number of first substrates included in the first substrate group 10 is not particularly limited.

  The first substrate 14 includes a photo interrupter 20 and a memory control unit (hereinafter referred to as “MCU”) 22. Further, the first substrate 14 includes a substrate 24 on which the photo interrupter 20 and the MCU 22 are mounted, and a connector 26 for outputting a signal generated by the MCU 22.

  The photo interrupter 20 is a reflective photo interrupter. The photo interrupter 20 can output a detection signal corresponding to the distance to the detection target when the detection target approaches. Eight photo interrupters 20 are arranged on the substrate 24. The photo interrupters 20 are arranged in a row on the substrate 24. The number and arrangement of the photo interrupters 20 are not limited to this. The photo interrupter 20 is connected to the MCU 22 by wiring printed on the substrate 24. The photo interrupter 20 outputs a detection signal to the MCU 22. The structure and detection principle of the photo interrupter 20 will be described later in detail.

  The MCU 22 is a microprocessor that calculates information on the position of the detection target (hereinafter referred to as “position information”) based on the detection signal output from the photo interrupter 20. The MCU 22 is connected to the connector 26 by wiring printed on the substrate 24. The connector 26 is connected to the second substrate 12 via the cable 13. The MCU 22 outputs the calculated position information to the second substrate 12 via the connector 26 and the cable 13. Note that the first substrate 14 may be configured to wirelessly transmit the position information calculated by the MCU 22 to the second substrate 12. In such a case, the first substrate 14 and the second substrate 12 may be configured to include a communication unit for transmitting and receiving position information.

  The board | substrate 24 is a flexible board | substrate (Flexible printed circuits) with which the wiring was printed, for example. The substrate 24 is, for example, a polyimide film. According to this, the board | substrate 24 can have flexibility. Thereby, even when the surface on which the substrate 24 is installed is a curved surface (the side surface of the robot arm or the like), the substrate 24 can be installed along the curved surface. The substrate 24 may be a substrate that does not have flexibility.

  Since the first substrates 16 and 18 have the same configuration as that of the first substrate 14, the same reference numerals are given to the same configurations and the description thereof is omitted.

  The second substrate 12 includes a substrate 28, an input connector 30, a microprocessor 32, and an output connector 34. An input connector 30, a microprocessor 32, and an output connector 34 are mounted on the substrate 28. On the board 28, wirings for connecting the input connector 30, the microprocessor 32, and the output connector 34 are printed. The input connector 30 is connected to the cable 13.

  The microprocessor 32 is connected to the input connector 30 and the output connector 34 by wiring printed on the substrate 28. The output connector 34 is connected to the control unit 38 via the cable 36. The control unit 38 is, for example, a control unit of a robot in which the proximity sensor 1 is assembled. A plurality of pieces of position information calculated by the MCUs 22 of the first substrates 14, 16, and 18 are input to the microprocessor 32 via the input connector 30. For example, the microprocessor 32 compares the plurality of pieces of position information to identify the photo interrupter 20 that is closest to the detection target. For example, the microprocessor 32 outputs information indicating which photo interrupter 20 is closest to the control unit 38. Or as above-mentioned, each photo interrupter 20 can output the detection signal according to the distance with a detection target object, ie, distance information. Therefore, the microprocessor 32, for example, based on the position information of each photo interrupter 20 in the two-dimensional plane and the distance information corresponding to the distance from each photo interrupter 20 to the detection target, for example, the three-dimensional of the detection target. And at least one of the position and the three-dimensional shape can be calculated.

  The first board group 10 and the second board 12 are connected to the connector 26 of the first board 14, 16, 18 and the input connector 30 of the second board 12 via the cable 13. It is not limited. The first board group 10 and the second board 12 are, for example, the second board 12 including three input connectors 30, and the connectors 26 of the first boards 14, 16, and 18 are individually connected to the input connectors 30. It is good also as a structure.

(Photo-interrupter)
Next, the photo interrupter 20 of this embodiment will be described with reference to FIGS. FIG. 2 is a perspective view showing an example of the photo interrupter of the present embodiment. FIG. 3 is an exploded perspective view showing an example of the photo interrupter of the present embodiment. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a bottom view showing an example of the cover of the present embodiment. The mounting side MS shown in FIG. 2 is the side on which the photo interrupter 20 is mounted on the first substrates 14, 16, 18 when viewed from the photo interrupter 20. The detection side DS shown in FIG. 2 is opposite to the mounting side MS when viewed from the photo interrupter 20.

  As shown in FIGS. 2 and 3, the photo interrupter 20 is a reflection type photo interrupter. The photo interrupter 20 includes a sensor unit 50 and a cover 100. The sensor unit 50 includes a light emitting unit 52, a light receiving unit 54, and a substrate 56 on which the light emitting unit 52 and the light receiving unit 54 are disposed. The sensor unit 50 includes a first light shielding wall 58, a first sealing member 60, and a second sealing member 62.

  As shown in FIG. 4, the light emitting unit 52 is a light emitting diode that emits infrared light. The light emitting unit 52 is arranged on the arrangement surface 64 of the substrate 56. The arrangement surface 64 is a surface on the detection side DS of the substrate 56. The light emitting unit 52 is electrically connected to the bump 66. The bump 66 is an electrode connected to the wiring printed on the first substrate 14, 16, 18. Electric power is supplied to the light emitting unit 52 from the first substrates 14, 16, 18 through the bumps 66.

  As shown in FIGS. 3 and 4, the light receiving portion 54 is disposed on the arrangement surface 64 of the substrate 56. The light receiving unit 54 can detect reflected light that is emitted from the light emitting unit 52 and reflected from the detection target. The light receiving unit 54 outputs a photocurrent (detection signal) according to the intensity of infrared light incident on the light receiving unit 54. That is, the light receiving unit 54 is a phototransistor having sensitivity to infrared rays. The light receiving unit 54 is electrically connected to the bump 68. The bump 68 is an electrode connected to the wiring printed on the first substrate 14, 16, 18. The light receiving unit 54 is connected to the MCU 22 via bumps 68 and wiring printed on the first substrates 14, 16, and 18. The light receiving unit 54 outputs a photocurrent corresponding to the intensity of infrared light incident on the light receiving unit 54 to the MCU 22.

  As shown in FIGS. 3 and 4, the first light shielding wall 58 is arranged on the arrangement surface 64 of the substrate 56 so as to separate the light emitting unit 52 and the light receiving unit 54. The first light shielding wall 58 is a plate-shaped member. The first light shielding wall 58 protrudes from the arrangement surface 64 in a direction perpendicular to the light emitting unit 52 and the light receiving unit 54. The facing surface 70 shown in FIG. 4 is a surface on the detection side DS of the first light shielding wall 58. The facing surface 70 is a surface substantially parallel to the arrangement surface 64. The first light shielding wall 58 is made of an opaque resin, for example. Accordingly, the first light shielding wall 58 can prevent light emitted from the light emitting unit 52 from directly entering the light receiving unit 54. The shape and material of the first light shielding wall 58 are not limited to this. The first light shielding wall 58 may be any shape and material that can prevent light emitted from the light emitting unit 52 from directly entering the light receiving unit 54.

  The first arrangement surface 72 shown in FIG. 4 is a surface on the side where the light emitting unit 52 is arranged among the arrangement surfaces 64 partitioned by the first light shielding wall 58. The second arrangement surface 74 shown in FIG. 4 is a surface on the side where the light receiving unit 54 is arranged among the arrangement surfaces 64 partitioned by the first light shielding wall 58. As shown in FIG. 3, the first sealing member 60 and the second sealing member 62 are transparent resins. The first sealing member 60 and the second sealing member 62 are formed by, for example, a resin mold. As shown in FIG.3 and FIG.4, the 1st sealing member 60 and the 2nd sealing member 62 are substantially rectangular parallelepiped shapes. An upper surface 61 illustrated in FIG. 4 is a surface on the detection side DS of the first sealing member 60. An upper surface 63 illustrated in FIG. 4 is a surface on the detection side DS of the second sealing member 62. The first sealing member 60 is formed so as to cover the first arrangement surface 72 from the detection side DS. The second sealing member 62 is formed so as to cover the second arrangement surface 74 from the detection side DS. The first sealing member 60 is formed so that the height from the first arrangement surface 72 is the same as that of the facing surface 70. The second sealing member 62 is formed so that the height from the second arrangement surface 74 is the same as that of the facing surface 70.

  The sensor unit 50 is mounted on the first substrate 14, 16, 18 by flip chip mounting. The flip chip mounting is a mounting method in which the bumps 66 and 68 of the sensor unit 50 and the wiring printed on the first substrate 14, 16 and 18 are directly connected. In addition, the mounting method of the sensor part 50 is not limited to this. For example, the sensor unit 50 may include a lead that connects the light emitting unit 52 and the light receiving unit 54 to the wiring printed on the first substrate 14, 16, 18 instead of the bumps 66, 68.

  As shown in FIG. 3, the cover 100 includes a first light transmissive member 102, a second light transmissive member 104, and a frame member 106.

  As shown in FIG. 4, the 1st translucent member 102 and the 2nd translucent member 104 are plate-shaped members. As shown in FIG. 5, the first light transmissive member 102 and the second light transmissive member 104 have a rectangular shape in plan view. The thickness d1 illustrated in FIG. 4 is the thickness of the first light transmissive member 102. The thickness d2 illustrated in FIG. 4 is the thickness of the second light transmissive member 104. The outer side surface 108 shown in FIGS. 4 and 5 is a side surface of the first light transmissive member 102. The outer side surface 110 shown in FIGS. 4 and 5 is a side surface of the second light transmissive member 104. The first light transmissive member 102 is fitted and fixed to the first opening 118 of the frame member 106 at a position covering the detection side DS of the light emitting unit 52. The second translucent member 104 is fitted and fixed to the second opening 120 of the frame member 106 at a position covering the detection side DS of the light receiving unit 54. The first light transmissive member 102 or the second light transmissive member 104 is, for example, an optical filter that reduces disturbance light. An optical filter is a band pass filter which permeate | transmits only infrared rays, for example. Therefore, the second light transmissive member 104 can reduce light having a wavelength other than infrared light even when disturbance light is incident on the light receiving unit 54. According to this, it can suppress that the light-receiving part 54 detects light other than the reflected light which was irradiated from the light emission part 52, and was reflected from the detection target object. As a result, the photo interrupter 20 can detect the detection target with high accuracy.

  Note that the first light transmissive member 102 and the second light transmissive member 104 may use an optical filter other than the bandpass filter in accordance with the environment to which the photo interrupter 20 is applied. The first light transmissive member 102 and the second light transmissive member 104 may be, for example, a short-pass filter that reduces light having a wavelength longer than infrared light. Moreover, the 1st translucent member 102 and the 2nd translucent member 104 may be a long pass filter which reduces the light of a wavelength shorter than infrared rays, for example.

  The first light transmissive member 102 may be a transmissive member instead of the optical filter. A transparent member is glass or translucent resin, for example. According to this, a transparent member cheaper than the optical filter can be applied to the photo interrupter 20. As a result, the cost of the photo interrupter 20 can be reduced.

  As shown in FIG. 4, the frame member 106 is a member that fixes the first light transmitting member 102 and the second light transmitting member 104 to the sensor unit 50. The frame member 106 is a substantially concave member that is recessed from the mounting side MS toward the detection side DS. The frame member 106 includes an upper plate member 112 that is a member facing the detection side DS of the frame member 106, and a cylindrical rectangular tube member 114. The upper plate member 112 and the rectangular tube member 114 are opaque resin. The upper plate member 112 and the rectangular tube member 114 are integrally formed by, for example, injection molding.

  The upper plate member 112 includes a pressing surface 116, a pair of first openings 118 and second openings 120, and a second light shielding wall 122. The holding surface 116 is a surface on the mounting side MS of the upper plate member 112. The pressing surface 116 is a surface that presses the first light transmitting member 102 and the second light transmitting member 104 from the detection side DS. The first opening 118 and the second opening 120 are holes that penetrate the upper plate member 112 from the mounting side MS toward the detection side DS.

  As shown in FIGS. 4 and 5, the second light shielding wall 122 is a bar-shaped member disposed between the first opening 118 and the second opening 120 when viewed from the mounting side MS. The second light shielding wall 122 is formed integrally with the upper plate member 112. When the first translucent member 102 is fitted into the first opening 118 of the frame member 106 and the second translucent member 104 is fitted into the second opening 120 of the frame member 106, the first translucent member 102 and the second translucent member A second light shielding wall 122 is disposed between the member 104 and the member 104. Accordingly, the position of the second light shielding wall 122 is appropriately positioned between the first light transmissive member 102 and the second light transmissive member 104. When the second light shielding wall 122 is formed integrally with the upper plate member 112, the positioning accuracy of the position of the second light shielding wall 122 is increased. The second light shielding wall 122 is separate from the upper plate member 112 and may be attached to the upper plate member 112. According to this, it is possible to use a material having a high moldability for the upper plate member 112 by using a material having a high light shielding property by the second light shielding wall 122.

  As shown in FIG. 4, the second light shielding wall 122 has a rectangular cross section. The thickness d3 illustrated in FIG. 4 is the thickness of the second light shielding wall 122. The thickness d3 is slightly larger than the thickness d1 of the first light transmissive member 102 and the thickness d2 of the second light transmissive member 104. The second light shielding wall 122 includes a first side surface 124, a second side surface 126, and an opposing surface 128. The first side surface 124 is a surface that contacts the outer side surface 108 of the first light transmissive member 102. The second side surface 126 is a surface that contacts the outer surface 110 of the second light transmissive member 104. The second light shielding wall 122 includes a first side surface 124 facing the facing surface 70 of the first light shielding wall 58 on the mounting side MS. The facing surface 70 of the first light shielding wall 58 and the first side surface 124 of the second light shielding wall 122 are in contact with each other. In addition, in this embodiment, being in contact includes surface contact and partial contact.

  As shown in FIGS. 4 and 5, the rectangular tube member 114 is a hollow cylindrical member. One end surface of the rectangular tube member 114 is joined to the outer periphery of the upper plate member 112. The rectangular tube member 114 includes an outer surface 130 that is an outer surface of the tube and an inner surface 132 that is an inner surface of the tube. As shown in FIG. 5, the outer side surface 130 and the inner side surface 132 are rectangular when viewed from the mounting side MS. As shown in FIGS. 4 and 5, the inner side surface 132 is in contact with the first side surface 124 of the second light shielding wall 122 over the entire circumference of the outer side surface 108 and the outer side surface 108 of the first light transmissive member 102. . In other words, the first translucent member 102 is fitted into the first opening 118 of the frame member 106 and is fixed by a clearance fit. The inner side surface 132 is in contact with the second side surface 126 of the second light shielding wall 122 over the entire circumference of the outer side surface 110 and the outer side surface 110 of the second light transmissive member 104. In other words, the second translucent member 104 is fitted into the second opening 120 of the frame member 106 and is fixed by a clearance fit. Further, the inner side surface 132 is in contact with the side surface 57 of the substrate 56 over the entire circumference. According to this, the frame member 106 can fix the first light transmissive member 102 and the second light transmissive member 104 to the substrate 56.

  FIG. 6 is a schematic cross-sectional view illustrating a state in which light emitted from the light emitting unit of the photo interrupter of the comparative example is reflected by the light transmissive member. The comparative example shown in FIG. 6 shows an example in which the translucent member 202 is fixed to the sensor unit 50 via the adhesive 204 unlike the photo interrupter 20 of the present embodiment. With reference to FIG. 6, how the light emitted from the light emitting unit 52 is reflected by the translucent member 202 is described.

  The photo interrupter 200 of the comparative example is the same as the photo interrupter 20 of this embodiment except that the cover 100 is replaced with a translucent member 202 and an adhesive 204. The translucent member 202 is fixed to the upper surfaces 61 and 63 and the facing surface 70 via an adhesive 204. The first reflecting surface 206 shown in FIG. 6 is a surface on the mounting side MS of the translucent member 202. A second reflecting surface 208 shown in FIG. 6 is a surface on the detection side DS of the translucent member 202. The incident light L3 illustrated in FIG. 6 is an example of light that is incident on the first reflecting surface 206 from the light emitting unit 52. The reflected light L4 shown in FIG. 6 is an example of the incident light L3 reflected by the first reflecting surface 206. The incident light L5 shown in FIG. 6 is an example of light that enters the second reflecting surface 208 from the light emitting unit 52. The reflected light L6 shown in FIG. 6 is an example of the incident light L3 reflected by the second reflecting surface 208.

  As shown in FIG. 6, the translucent member 202 and the sensor unit 50 are arranged apart from each other by the thickness of the adhesive 204. Accordingly, the incident light L3 is incident between the first reflecting surface 206 and the facing surface 70 and is reflected by the first reflecting surface 206. According to this, the reflected light L4 is incident on the light receiving unit 54. Thereby, even when the detection target object is not in proximity to the photo interrupter 200, the light receiving unit 54 detects the light of the light emitting unit 52. As a result, the offset value of the photocurrent output from the light receiving unit 54 becomes large. Further, the reflected light L4 has a larger luminous flux as the adhesive 204 is thicker. Accordingly, the light intensity of the reflected light L4 increases as the adhesive 204 is thicker. According to this, in the photo interrupter 200 of the comparative example, the offset value of the output current of the light receiving unit 54 varies depending on the thickness of the adhesive 204. Accordingly, it is difficult to manufacture the photo interrupter 200 of the comparative example so that the offset value is within the design value. As a result, the yield of the photo interrupter 200 of the comparative example decreases.

  The translucent member 202 is disposed so as to cover the facing surface 70 when viewed from the detection side DS. According to this, the incident light L <b> 5 is reflected by the second reflecting surface 208 and enters the light receiving unit 54. Therefore, more light leaks from the light emitting unit 52 to the light receiving unit 54. According to this, in the photo interrupter 200, the light receiving unit 54 detects the light of the light emitting unit 52 even when the detection target object is not close.

  As shown in FIG. 4, in the photo interrupter 20 of the present embodiment, the second light shielding wall 122 is formed between the first light transmissive member 102 and the second light transmissive member 104. According to this, even when the incident light L1 incident on the first light transmitting member 102 from the light emitting portion 52 is reflected by the surface of the detection side DS of the first light transmitting member 102, the reflected light L2 does not enter the light receiving portion 54. . Thereby, the photo interrupter 20 can suppress light leaking from the light emitting unit 52 to the light receiving unit 54. Therefore, the photo interrupter 20 can suppress the offset value of the photocurrent output from the light receiving unit 54 from increasing. As a result, the detection accuracy of the photo interrupter 20 can be improved.

  As shown in FIG. 4, in the photo interrupter 20 of the present embodiment, the thickness d3 of the second light shielding wall 122 is thicker than the thickness d1 of the first light transmissive member 102 and the thickness d2 of the second light transmissive member 104. . Further, as described above, the first light shielding wall 58 and the second light shielding wall 122 are in contact with each other in the vertical direction of the substrate 56 (the normal direction of the surface of the substrate 56). According to this, even when light incident on the first light transmissive member 102 from the light emitting portion 52 is reflected by the mounting side MS of the first light transmissive member 102, no light is directly incident on the light receiving portion 54. Thereby, the photo interrupter 20 can suppress the offset value of the photocurrent output from the light receiving unit 54 from increasing. As a result, the detection accuracy of the photo interrupter 20 can be improved. Therefore, the facing surface 70 and the facing surface are controlled by quality control so that the thickness d1 of the first light transmitting member 102 and the thickness d2 of the second light transmitting member 104 are smaller than the thickness d3 of the second light shielding wall 122. 128 can be reliably brought into contact with. According to this, the proximity sensor 1 of the present embodiment can suppress the offset value of the photocurrent output from the light receiving unit 54 from varying for each photo interrupter 20. As a result, the proximity sensor 1 can detect which photo interrupter 20 is the photo interrupter 20 closest to the detection target with higher accuracy.

  In the photo interrupter 20 of this embodiment, it is preferable that the frame member 106 is formed of a heat conductive good material such as a heat conductive resin or black painted aluminum. According to this, the heat generated in the light emitting unit 52 can be efficiently radiated. Thereby, the light-emitting part 52 and the light-receiving part 54 can be kept in a low temperature state. As a result, the element lifetime of the light emitting unit 52 or the light receiving unit 54 can be extended. The heat conductive resin is one or more kinds of heat among alumina, aluminum nitride, boron nitride, copper, aluminum, graphite, carbon nanotube (CNT), boron nitride nanotube (BNNT), etc. as a heat conductive filler. Highly conductive particles are mixed.

  In the photo interrupter 20 of the present embodiment, the first light transmitting member 102 and the second light transmitting member 104 are fixed to the frame member 106 with an interference fit. The inner surface 132 of the frame member 106 is in contact with the side surface 57 of the substrate 56 over the entire circumference. According to this, the frame member 106 can fix the positions of the first light transmitting member 102 and the second light transmitting member 104 with respect to the sensor unit 50. Therefore, the first light transmissive member 102 and the second light transmissive member 104 can be fixed to the sensor unit 50 without using an adhesive. According to this, the adhesive is not interposed between the first light transmitting member 102 and the second light transmitting member 104 and the sensor unit 50. Thereby, the light reflected by the lower surface of the first light transmissive member 102 does not enter the adhesive and enter the light receiving unit 54. As a result, leakage light that enters the light receiving unit 54 from the light emitting unit 52 can be suppressed. The first light transmissive member 102 and the second light transmissive member 104 may be fixed to the frame member 106 with an intermediate fit.

DESCRIPTION OF SYMBOLS 1 Proximity sensor 20 Photointerrupter 32 Microprocessor 50 Sensor part 52 Light emission part 54 Light reception part 56 Board | substrate 58 1st light shielding wall 60 1st sealing member 62 2nd sealing member 70,128 Opposing surface 100 Cover 102 1st light transmission Member 104 Second light transmitting member 106 Frame member 118 First opening 120 Second opening 122 Second light shielding wall 132 Inner side surfaces L1, L3, L5 Incident light L2, L4, L6 Reflected light

Claims (8)

A light emitting unit that emits light;
A light receiving unit for detecting reflected light of the light irradiated on the detection target;
A substrate on which the light emitting unit and the light receiving unit are disposed;
A first light-shielding wall provided on the substrate between the light-emitting unit and the light-receiving unit;
A first light transmissive member facing the light emitting portion, a second light transmissive member facing the light receiving portion, and a second light shielding wall provided between the first light transmissive member and the second light transmissive member. And a cover provided so as to be opposed to the substrate.   The photo interrupter according to claim 1, wherein the first light shielding wall and the second light shielding wall are in contact with each other in a vertical direction of the substrate.   The photo interrupter according to claim 1, wherein the cover includes a frame member having a pair of openings in which the first light transmissive member and the second light transmissive member are fitted and fixed.   4. The photointerrupter according to claim 1, wherein the second light transmitting member is an optical filter that reduces disturbance light. 5.   5. The photointerrupter according to claim 1, wherein the first light transmitting member is an optical filter that reduces disturbance light. 6.   5. The photointerrupter according to claim 1, wherein the first light transmissive member is made of glass or resin.   The photo interrupter according to claim 1, wherein the cover is made of a heat conductive resin or aluminum. A plurality of photo-interrupters according to any one of claims 1 to 7;
A proximity sensor, comprising: a microprocessor that calculates a distance from the photo interrupter to the detection target based on a detection signal detected by the photo interrupter.

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