PROXIMITY SENSOR

Abstract

Proximity sensor (1, 1a) with a sensing coil, the sensor comprising: a substrate (14) provided in a housing (11) in which a signal processing circuit (20) is formed, and in which a normal direction of the substrate (14) is oriented with a direction perpendicular to an axial direction of the sensing coil (13); a light-emitting element (15, 151, 152) provided on the substrate and emitting light in the axial direction of the sensing coil (13); a light-scattering section (16a) in which light emitted by the light-emitting element (15, 151, 152) is scattered in a direction other than the axial direction;and a light guide section (16b) that directs the light scattered by the light scattering section (16a) to a display area (21, 211, 212) provided on a side surface of the housing, wherein the light guide section (16b) has a plurality of partial light guide sections (16b) that direct light in a radial direction (D3) from an axis of the sensing coil (13), and the light guide section (16b) is configured with a cross-shaped light guide path (16) formed by the partial light guide sections (16b) to reflect the light first scattered by the light scattering section (16a) from a diffusion direction (D2) thereafter in the radial direction (D3) to direct the light scattered by the light scattering section (16a) to the display area (21, 211, 212).

Description

BACKGROUND OF THE REVELATION Territory of Revelation The information refers to a proximity sensor. Description of the state of the art In state-of-the-art proximity sensors, visibility of approximately 180 degrees is achieved by mounting an LED (Light Emitting Diode) on the surface of a substrate. To guarantee all-around visibility, LEDs must be mounted on both surfaces of the substrate. Additionally, the LED mounted on the substrate is positioned at a distance from the display area and is filled with an opaque epoxy resin. Therefore, it is difficult to visually detect the display area, which has high luminance. For example, document 1 reveals a configuration of a proximity sensor that includes a reflective surface which reflects the light emitted by a light-emitting element onto a display window, which is an end section on a page. In the configuration of document 1, all-around visibility cannot be guaranteed. [Documents on the state of the art] [Printed materials] [Publication 1] Japanese unexamined patent application Publication No. JP 2007-035583 A (published on February 8, 2007) [Publication 2] Japanese unexamined patent application Publication No. JP 2011-165323 A (published on August 25, 2011) OVERVIEW OF THE REVELATION A technology for ensuring all-around vision using a single light-emitting element is proposed. For example, Document 2 reveals a configuration of a proximity sensor comprising a tubular light guide section with a first light-emitting surface through which light emitted by a light-emitting element is transmitted and directly emitted outwards; a reflective surface that reflects light emitted by the light-emitting element and directs the light in a circumferential direction within the tubular light guide section; and a second light-emitting surface through which light reflected from the reflective surface and propagated within the tubular light guide section is emitted outwards. However, in the proximity sensor of the printed text 2, the second light-emitting surface is limited in size, and it can be difficult to ensure omnidirectional visibility with high luminance. The aim of one aspect of the revelation is to ensure the all-round visibility of a high-luminance proximity sensor using a single light-emitting element. To solve the problems, according to one aspect of the disclosure, there is a proximity sensor with a detection coil. The proximity sensor comprises a substrate provided in a housing in which a signal processing circuit is formed, and in which a normal direction of the substrate is aligned with a direction perpendicular to an axial direction of the detection coil; a light-emitting element provided on the substrate that emits light in the axial direction of the detection coil; a light-scattering section that scatters light emitted by the light-emitting element in a direction other than the axial direction; and an optical fiber section. As in the configuration described above, many proximity sensors are configured to have a substrate oriented so that its normal direction is aligned with the direction perpendicular to the axial direction of the detection coil. In such a configuration, if the light-emitting element is simply placed on the substrate, light can be directed perpendicular to the surface on which the light-emitting element is located, but it cannot be directed towards the back of the surface on which the light-emitting element is located. In contrast, according to the configuration described above, the light-emitting element can emit light in the axial direction of the sensing coil, the light-scattering section can scatter light in a direction other than the axial direction, and the light guide section can direct light to the display area provided on the side of the housing. This makes it possible to ensure visibility over a wider directional range with high luminance using a single light-emitting element. In the proximity sensor according to the aspect of the disclosure, the light guide section contains a plurality of partial light guide sections that guide light in a radial direction from an axis of the sensing coil. Depending on the configuration, the light can be directed in multiple directions. This allows light to be visually detected from several directions. In the proximity sensor according to one aspect of the disclosure, the multiple partial light guide sections are provided four times and arranged at intervals of 90 degrees around the axis. Depending on the configuration, the light is directed in four directions with equal intervals between them. This allows light to be visually detected in all directions. According to the disclosure, in the proximity sensor, a wiring connection that links the circuit on the substrate to the detection coil is arranged in an area between the adjacent partial optical fiber sections. Depending on the configuration, the light can be routed without the need for wiring. In the proximity sensor, the light scattering section is formed from an opaque resin, taking into account the aspect of revelation. Depending on the configuration, the light diffusion section is made of an opaque resin. This allows the light to be effectively diffused. In the proximity sensor according to the disclosure, the light-emitting element comprises a first light-emitting element and a second light-emitting element, whose emitted colored lights are different from one another. The first light-emitting element is located on one surface of the substrate, and the second light-emitting element is located on the other surface of the substrate. The light-scattering section comprises a first light-scattering section that diffuses the light emitted by the first light-emitting element in a direction other than the axial direction, and a second light-scattering section that diffuses the light emitted by the second light-emitting element in a direction other than the axial direction.The light guide section consists of a first light guide section that directs the light scattered by the first light scattering section into the display area, and a second light guide section that directs the light scattered by the second light scattering section into the display area. Depending on the configuration, the light emitted by the first and second light-emitting elements is diffused by the different light-scattering sections and guided to the display area by the different light guide sections. This allows differently emitted colored lights to be clearly distinguished visually. According to the disclosure, the proximity sensor includes a light-shielding scattering element between the first light guide section and the second light guide section. Depending on the configuration, the light-shielding diffusing element is positioned between the two light guide sections, ensuring that differently emitted colored lights are directed unmixed into the display area. This makes it easier to visually distinguish between differently emitted colored lights. In the proximity sensor according to the point of view of revelation, the first light-emitting element emits light to a fastening element that secures the wiring, and the second light-emitting element emits light to the detection coil. Depending on the configuration, the two light-emitting elements emit light in the axial direction of the detection coil and in the opposite direction, thus helping to guide the emitted lights to the display area via different paths. The proximity sensor according to the disclosure further includes a bore provided in the substrate through which the light scattered by the second light scattering section passes. Depending on the configuration, even if the second light-emitting element is located on the other surface of the substrate, the substrate still has the hole through which the light passes. Therefore, the light emitted by the second light-emitting element can travel not only to the other surface of the substrate, but also to the one surface of the substrate. The aspect of revelation demonstrates an effect that ensures omnidirectional visibility of the proximity sensor with high luminance using a single light-emitting element. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1(a) and 1(b) are views illustrating the structure of a proximity sensor according to embodiment 1 of the disclosure. Figure 1(a) shows the assembly of the proximity sensor, and Figure 1(b) shows a configuration of components of the proximity sensor. Figures 2(a) to 2(c) are views illustrating a detailed structure of the proximity sensor according to embodiment 1 of the disclosure. Figure 2(a) is a side view of the proximity sensor, Figure 2(b) is a cross-sectional view of the proximity sensor, and Figure 2(c) shows the direction in which light travels within the proximity sensor. Figures 3(a) to 3(d) are views illustrating the structure of a proximity sensor according to embodiment 2 of the disclosure. Fig. 3(a) and Fig. 3(b) are perspective views of the proximity sensor, Fig. 3(c) is a cross-section of the proximity sensor and Fig. 3(d) shows a direction in which light moves in the proximity sensor. DESCRIPTION OF THE EXECUTION FORMS [Version 1] In the following, embodiment 1 of the disclosure is described in detail with reference to Figs. 1(a) to 2(c). Figures 1(a) and 1(b) are views illustrating the structure of a proximity sensor 1 according to the present embodiment. Figure 1(a) shows the structure of the proximity sensor 1. Figure 1(b) is a view illustrating a configuration of components of the proximity sensor 1. The proximity sensor 1 detects the presence / absence or position of a metal body by utilizing a magnetic field. As shown in Fig. 1(a), the proximity sensor 1 comprises a metal housing (case) 11, a tubular optical fiber section (case) 12, a coil section (detection coil) 13, a substrate 14, a light-emitting element 15, a cross-shaped optical fiber path 16, cable cores (wiring) 17, a cable (wiring) 18 and a fastening element 19. As shown in Fig. 1(b), the proximity sensor 1 is divided into the metal housing 11, the tubular light guide section 12, the coil section 13, the substrate 14, the cross-shaped light guide path 16 and the cable 18. The light-emitting element 15 and a control unit 20 are mounted in the substrate 14. The metal housing 11 is a cylindrical housing, one end of which is blocked by the coil section 13. The metal housing 11 is internally fitted with the substrate 14, the wires 17, and the like. An opaque resin fills a gap in the metal housing 11 to fix the individual components. Epoxy, urethane, acrylic, hot melt adhesive, rubber, silicone, or similar materials are used for the opaque resin, which is preferably white. Since these resins can emit diffuse light, they can be used as fillers for the proximity sensor 1. The tubular optical fiber section 12 secures the cable 18. A display area 21 is arranged within the tubular optical fiber section 12, which causes light emitted through a window of the cross-shaped optical fiber path 16 to be radiated outwards. The coil section 13 is a circuit for generating resonance when approaching a metal. The substrate 14 is a substrate provided within the metal housing 11, on which the control unit 20 (signal processing circuit) is mounted, and in which a normal direction of the substrate is aligned with a direction perpendicular to an axial direction of the coil section 13. As shown in Fig. 1(b), electronic components, including the light-emitting element 15 and the control unit 20, are mounted on the substrate 14, which is electrically connected to the cable 18. The light-emitting element 15 is positioned on the substrate 14, with one light-emitting part oriented straight to the side (parallel to the surface of the substrate 14), and emits light in the axial direction of the coil section 13 in accordance with an instruction from the control unit 20. An LED (light-emitting diode) or similar is used for the light-emitting element 15. The light-exiting element 15 is housed in the cross-shaped light guide path 16. The cross-shaped optical fiber 16 is a cross-shaped combination of four parts, the entire assembly being covered with an opaque resin or similar material. The cross-shaped optical fiber 16 houses the light-emitting element 15, internally diffuses and reflects the light emitted by the light-emitting element 15, and directs the light to the display window. The cross-shaped optical fiber 16 comprises a light-diffusing section 16a, which diffuses the light emitted by the light-emitting element 15 in a direction other than the axial direction of the coil section 13, and an optical fiber section 16b, which directs the light diffused by the light-diffusing section 16a to the display area 21 provided on a side face of the tubular optical fiber section 12. The optical fiber section 16b contains a plurality of partial optical fiber sections that guide the light radially from an axis of the coil section 13. As shown in Fig. 1(b), four partial optical fiber sections are provided, arranged at intervals of 90 degrees around the axis of the coil section 13. The conductor wires 17 are conductor wires within the cable 18 and are inserted into the metal housing 11 from the other end through a resin component, which is not the cross-shaped optical fiber path 16. The cable 18 contains a conductor that is soldered to the substrate 14. The cable 18 transmits an electrical signal and supplies power. The fastening element 19 is called a ring cable and secures the cable 18, including the conductor wires 17. The fastening element 19 is made of a resin or similar material. The control unit 20 is a circuit mounted on the substrate 14 and contains a CPU. The control unit 20 processes a signal transmitted by the coil section 13 and sends an electrical signal to the light-emitting element 15 and the cable 18. The display area 21 is located on the radial outer surface of the light guide tube 12. The display area 21 receives light emitted through the window of the cross-shaped light guide path 16 and emits the received light radially outwards from the metal housing 11 as scattered light. Figures 2(a) to 2(c) are views illustrating a detailed structure of the proximity sensor 1 according to the present embodiment. Figure 2(a) is a side view of the proximity sensor 1. Figure 2(b) is a cross-section through the proximity sensor 1. Figure 2(c) is a view illustrating the direction in which light travels within the proximity sensor 1 and is a view of the proximity sensor 1 in the direction of the arrow in Figure 2(b). As shown in Fig. 2(a), an opaque resin fills the interior of the proximity sensor 1. As shown in Fig. 2(b), the conductor wire 17, which connects the control unit 20 on the substrate 14 to the coil section 13, is arranged in a region between the adjacent partial optical fiber sections. That is, the cross-shaped optical fiber path 16 with four partial optical fiber sections is formed bypassing the four conductor wires 17. One end of the substrate 14 is arranged within the cross-shaped optical fiber path 16, and the light-emitting element 15 is mounted on the top of the substrate 14. In the tubular optical fiber section 12, four indicator rangefinders 21 are arranged every 90 degrees, corresponding to the cross-shaped optical fiber path 16. The fiber optic path is configured to take the form of a number corresponding to the number of wires (17). For example, if two wires are used, the shape of the fiber optic path itself becomes a column. With three wires, the fiber optic path also has a triangular column shape. As shown in Fig. 2(c), the light-scattering section 16a is filled with an opaque resin 30. The inside of the metal housing 11 is also filled with the opaque resin 30. The light-emitting element 15 emits light in the axial direction D1 of the coil section 13 towards the mounting element 19. Subsequently, the light-scattering section 16a of the cross-shaped light guide 16 diffuses the light emitted by the light-emitting element 15 in a direction other than the axial direction D1 of the coil section 13 (e.g., direction D2). The light guide section 16b of the cross-shaped light guide 16 reflects the light scattered by the light-scattering section 16a in the radial direction D3 and directs the light to the display area 21. The display area 21 is illuminated by light guided by the light guide section 16b. Depending on the configuration, in the proximity sensor 1, the light-emitting element 15 can emit light in the axial direction of the coil section 13, the light-diffusing section 16a can diffuse light in a direction other than the axial direction, and the light guide section 16b can direct light into the display area 21 provided on the side surface of the tubular light guide section 12. This makes it possible to ensure visibility over a wider directional range with high luminance using a single light-emitting element 15. Since the light can be directed in multiple directions, it can also be visually detected in multiple directions. In particular, because the light is guided through the four partial light guide sections in four directions with equal intervals between them, light can be visually detected in all directions. Structural components are then added to ensure the optical path is maintained and the conductor wires 17 are positioned in a way that does not block the light path of the light-emitting element 15. This means that the conductor wire 17 is located in the area between the adjacent partial optical fiber sections. This allows light to be guided without obstructing the conductor wires 17. Accordingly, the optical fiber path can accommodate four conductors. Since the light-diffusing section 16a is made of an opaque resin, the light can also be effectively diffused. According to the above description, usability for a user can be improved, and if the proximity sensor is installed, the user can easily check the function of a control output. Further effects are described below. (1) If added structural components play a role in a guide, generally provided in a clamp, the cable 18's fastening element 19 can increase in diameter, and it is easy to obtain the UL (Underwriters Laboratories Inc.) mark and similar certifications. (2) Since the light-emitting element 15 is typically mounted on both surfaces of the substrate 14 as a 360-degree indicator, power consumption increases. However, the present embodiment has the effect of preventing this increase in power consumption. (3) If the light-emitting element 15 is mounted on both surfaces of the substrate 14, there may be problems with an increase in the number of components and an increase in operating hours. However, the present embodiment has the effect of preventing these problems.(4) Since the cross-shaped optical fiber path 16 serves as a guide for the conductor wires 17, the positional relationship between the light-emitting element 15 and a soldering field can be clarified, and a disadvantage is avoided in that the conductor wires 17 cover the light-emitting element 15. [Version 2] Based on Figures 3(a) to 3(d), embodiment 2 of the disclosure can be described as follows. To simplify the description, the same reference numerals are used for elements that have the same functions as those of the elements described in the embodiment above, and their descriptions are omitted. Figures 3(a) to 3(d) are views illustrating the construction of a proximity sensor 1a according to the present embodiment. Figures 3(a) and 3(b) are perspective views of the proximity sensor 1a. Figure 3(c) shows a cross-section through the proximity sensor 1a. Figure 3(d) is a view illustrating one direction in which light travels within the proximity sensor 1a. As shown in Fig. 3(c), the light-emitting element comprises a light-emitting element (first light-emitting element) 151 and a light-emitting element (second light-emitting element) 152, the emitted colored lights of which are different. The light-emitting element 151 is located on the top (one surface) of the substrate 14. The light-emitting element 152 is located on the bottom (the other surface) of the substrate 14. A cross-shaped light guide path 161 houses the light-emitting element 151, internally diffuses and reflects the light emitted by the light-emitting element 151, and directs the light to a display area 211. A cross-shaped light guide path 162 houses the light-emitting element 152, internally diffuses and reflects the light emitted by the light-emitting element 152, and directs the light to a display area 212. As shown in Fig. 3(d), the light-emitting element 151 emits green light in the axial direction of the coil section 13 towards the mounting element 19. A light-scattering section (first light-scattering section) 161a of the cross-shaped light guide path 161 diffuses the light emitted by the light-emitting element 151 in a direction other than the axial direction of the coil section 13. A light guide section (first light guide section) 161b of the cross-shaped light guide path 161 directs the light scattered by the light-scattering section 161a to the display area 211. The light-emitting element 152 emits red light in the axial direction of the coil section 13. A light-scattering section (second light-scattering section) 162a of the cross-shaped light guide path 162 diffuses the light emitted by the light-emitting element 152 in a direction other than the axial direction of the coil section 13. A portion of the light scattered by the light-scattering section 162a travels upwards and passes through a hole 23 provided in the substrate 14. A light guide section (second light guide section) 162b of the cross-shaped light guide path 162 directs light that was scattered by the light-scattering section 162a and passed through the hole 23 to the display area 212. Additionally, a portion of the light scattered by the light-scattering section 162a is directed downwards and to the display area 212. A light-shielding scattering element 22 is provided between the light guide section 161b and the light guide section 162b, which causes light shielding and light scattering. Depending on the configuration, the emitted lights of the light-emitting element 151 and the light-emitting element 152 are scattered by the different light-scattering sections 161a and 162a, and the different light guide sections 161b and 162b direct the emitted lights to the display areas 211 and 212. This allows the emitted colored lights, which differ from each other, to be clearly visually distinguished. Since the light-shielding diffusing element 22 is provided between the two light guide sections 161b and 162b, the differently emitted colored lights are guided unmixed to the display areas 211 and 212. Therefore, the emitted colored lights, which differ from each other, can exhibit a clear contrast and be more visually distinct. The light-emitting element 151 emits light towards the fastening element 19, which secures the cables 18, and the light-emitting element 152 emits light towards the coil section 13. Depending on the configuration, the two light-emitting elements 151 and 152 emit light in the axial direction of the coil section 13 and in the opposite direction, thus helping to direct the emitted lights to the display areas 211 and 212 via different paths. The present embodiment further includes the hole 23 provided in the substrate 14, through which the light scattered by the light-scattering section 162a flows. Depending on the configuration, the substrate 14 has the hole 23 through which the light passes, even if the light-emitting element 152 is provided on the other surface of the substrate 14. Therefore, light emitted by the light-emitting element 152 can travel not only to the other surface of the substrate 14, but also to the one surface of the substrate 14. Embodiments 1 and 2 have a cable-extractable structure. However, the embodiment described in the disclosure also includes a connector structure. Examples of connector structures are a type in which a connector pin is soldered as a cable, and a type in which a cable harness is pulled out of a connector and soldered to the substrate. List of reference symbols 1, 1a Proximity sensor 11 Metal housing (housing) 12 Tubular light guide section (housing) 13 Coil section (detection coil) 14 Substrate 15 Light-emitting element 151 Light-emitting element (first light-emitting element) 152 Light-emitting element (second light-emitting element) 16a Light diffusion section 16b Light guide section (partial light guide section) 161a Light diffusion section (first light diffusion section) 161b Light guide section (first light guide section) 162a Light diffusion section (second light diffusion section) 162b Light guide section (second light guide section) 17 Wiring leads (wiring) 18 Cable (wiring) 21, 211, 212 Display area 22 Light-shielding diffusion element 23 Hole

Claims

Proximity sensor (1, 1a) with a sensing coil, the sensor comprising: a substrate (14) provided in a housing (11) in which a signal processing circuit (20) is formed, and in which a normal direction of the substrate (14) is oriented with a direction perpendicular to an axial direction of the sensing coil (13); a light-emitting element (15, 151, 152) provided on the substrate and emitting light in the axial direction of the sensing coil (13); a light-scattering section (16a) in which light emitted by the light-emitting element (15, 151, 152) is scattered in a direction other than the axial direction;and a light guide section (16b) that directs the light scattered by the light scattering section (16a) to a display area (21, 211, 212) provided on a side surface of the housing, wherein the light guide section (16b) has a plurality of partial light guide sections (16b) that direct light in a radial direction (D3) from an axis of the sensing coil (13), and the light guide section (16b) is configured with a cross-shaped light guide path (16) formed by the partial light guide sections (16b) to reflect the light first scattered by the light scattering section (16a) from a diffusion direction (D2) thereafter in the radial direction (D3) to direct the light scattered by the light scattering section (16a) to the display area (21, 211, 212). The proximity sensor according to claim 1, wherein four partial optical fiber sections (16b) are provided and are arranged at intervals of 90 degrees around the axis. The proximity sensor according to one of claims 1 to 2, wherein a wiring (17) connecting the circuit (20) on the substrate (14) to the sensing coil (13) is arranged in an area between the plurality of adjacent partial optical fiber sections (16b). The proximity sensor according to one of claims 1 to 3, wherein the light scattering section (16a) comprises an opaque resin. The proximity sensor according to any one of claims 1 to 4, wherein the light-emitting element (15) comprises a first light-emitting element (151) and a second light-emitting element (152), and the emitted colored light of the first light-emitting element (151) and the emitted colored light of the second light-emitting element (152) are different from each other, wherein the first light-emitting element (151) is provided on one surface of the substrate and the second light-emitting element (152) is provided on the other surface of the substrate, wherein the light-scattering section (16a) comprises a first light-scattering section (161a) which diffuses the light emitted by the first light-emitting element (151) in a direction other than the axial direction, and a second light-scattering section (162a) which diffuses the light emitted by the second light-emitting element (152) in a direction other than the axial direction. diffused, includesand wherein the optical fiber section (16b) comprises a first optical fiber section (161b) which directs the light scattered by the first light scattering section (161a) to the display area (21, 211, 212), and a second optical fiber section (162b) which directs the light scattered by the second light scattering section (162a) to the display area (21, 211, 212). The proximity sensor according to claim 5, wherein a light-shielding scattering element (22) is provided between the first light guide section (161b) and the second light guide section (162b). The proximity sensor according to claim 5 or 6, wherein the first light-emitting element (151) emits light in the direction of a fastening element that secures the wiring, and the second light-emitting element (152) emits light in the direction of the detection coil (13). The proximity sensor according to one of claims 5 to 7, further comprising: a hole (23) provided in the substrate (14) and through which the light scattered by the second light scattering section (162b) passes.

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