JPH0349123A - Proximity switch and manufacture thereof - Google Patents

Abstract

PURPOSE:To easily recognize a detection face at a dark place by partially exposing the region of the detection face on the surface of an exterior body, and providing a light guiding member guiding the light from light emitting elements and radiating it to the outside from an exposed section. CONSTITUTION:The detection display means of a proximity switch 10 is constituted of light emitting elements 18 and a light guiding member 12, and individual light emitting elements 18 are illuminated according to the detection of a detecting body. The light 19 emitted from individual light emitting elements 18 is guided to the front side through the inside of the cylindrical section 12a of a light shielding member 12, its most part is radiated to the front side from a ring-shaped exposed section 12b as shown by an arrow B directly or by scattering, and part of it is radiated to the side face from exposed sections 12c on side faces as shown by an arrow C by scattering. The ring-shaped exposed section 12b indicating the region of a detection face 6 and exposed sections 12c on side faces are illuminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a proximity switch that detects a detection object approaching a detection surface without contact by changes in an electric field, a magnetic field, etc., and a method for manufacturing the same.

[Conventional technology]

A typical proximity switch of this type is a high-frequency oscillation type proximity switch that detects the approach of a detection object by a change in the oscillation state, so this will be mainly explained below as an example.

FIG. 9 shows an example of a conventional proximity switch of this type. This proximity switch 2 has a detection coil, an oscillation circuit, etc. built into the case 4, and the front side of the detection coil is located close to the detection object. This serves as a detection surface 6 that performs detection. A mark 4a representing the area of this detection surface 6 is written on the case 4.

Further, normally, an operation indicator light 8 is provided on the front (in the illustrated example), side, or detection surface side of the case 4, which lights up when the proximity switch 2 enters the detection state.

The operation indicator light 8 is provided so that it can be visually confirmed on the spot when the proximity switch 2 is in the detection state (confirm visually, the same applies hereinafter).
This is because it is useful when adjusting the detection position of a detection object after the proximity switch 2 is attached to a partner device.

[Problem to be solved by the invention]

However, when adjusting the proximity switch 2 as described above in a dark place, the mark 4a that displays the detection surface 6 becomes difficult to see, making it difficult to visually recognize the detection surface 6. The problem was that it became difficult.

In addition, when the object to be detected is opaque such as a metal plate and is brought close to above the detection surface 6 from the direction of the operation indicator light 8 as shown by arrow A, the operation indicator light 8 is in the shadow of the detection object and its lighting state cannot be seen from above the detection surface 6, which also makes adjustment work difficult.To avoid this, the detection object approaches from a direction other than the operation indicator lamp The proximity switch 2 must be mounted in such a manner that the proximity switch 2 can be mounted in a limited direction.

Therefore, the present invention has an operation display means, and the operation display can be visually recognized no matter which direction the opaque detection object approaches, and the detection surface can be easily recognized even in a dark place. The main purpose is to provide a proximity switch.

[Means to solve the problem]

In order to achieve the above object, the proximity switch of the present invention has the following features:
Basically, one or more light emitting elements are housed inside an exterior body and emit light in response to the detection operation of a detection object, and a portion thereof is exposed on the surface of the exterior body so as to represent the area of the detection surface. and a light guiding member that guides light from the light emitting element and emits it to the outside from the exposed portion.

[Effect]

In the above proximity switch, the light emitting element and the light guide member constitute an operation display means, and when an object to be detected is detected, the exposed portion of the light guide member lights up to represent the region of the detection surface. That is, the operation display is performed to represent the area of the detection surface.6 Therefore, the detection surface can be easily recognized even in a dark place.

In addition, no matter which direction the object to be detected approaches, all of the exposed parts (shining parts) of the light guiding member will not be in the shadow of the object at once, so even if the object is opaque, it will always be visible. The operation display can be visually recognized.

〔Example〕

FIG. 1 is a perspective view showing a proximity switch according to an embodiment of the present invention.6 FIG. 2 is a sectional view taken along line I-1 in FIG. FIG. 3 is a block diagram showing an example of the electrical circuit of the proximity switch of FIG. 1.

The proximity switch 10 has an opaque case 4 made of an insulating material as an example of an exterior body, and includes an oscillation circuit 24 and an oscillation state detection circuit 26 as shown in FIG. 3, for example.
In this embodiment, a transparent light guiding member 12 having a cylindrical portion 12a is provided on the upper surface side of the printed circuit board 16 on which the output circuit 2 is mounted. A detection coil 20 having a core (bot core) 20a, a bobbin 20b, and a coil 20c is housed inside thereof. This detection coil 20 is connected to an oscillation circuit 24 shown in FIG. 3, and its front side serves as the detection surface 6 described above.

For example, an L
In this example, a plurality of light emitting elements I8 such as ED chips are provided. The number and arrangement of the light emitting elements 12 are preferably such that they can illuminate the ring-shaped exposed portion 12b and side exposed portions 12c, which will be described later, of the light guide member 12 as uniformly as possible. Exposed part 12c
Each light emitting element 1 may be arranged in a cross shape to correspond to
8 are respectively connected to an output circuit 28 shown in FIG. 3, and emit light all at once in response to the detection operation of the object to be detected.

The light guide member 12 is connected to its cylindrical portion 12a, and has a ring-shaped portion exposed on the surface of the case 4 so as to represent the area of the detection surface 6, that is, to surround the detection surface 6 in this example. It has an exposed portion 12b and, in this example, four side exposed portions 12c which are connected to the exposed portion 12b and are respectively exposed on four surfaces that intersect with the detection surface 6 of the case 4.

A lead wire 14 for output and power supply, for example, is connected to the printed circuit board 16, more specifically, to an output circuit 28 mounted thereon, and is drawn out of the case 4.

The case 4 is filled with a resin 22 such as epoxy resin for fixing the internal structure and for waterproofing/moisture proofing.

Note that the cylindrical portion 12a of the light guide member 12 and the light emitting element 18
There is no particular problem if the transparent resin 22 is inserted between the
In order to prevent this, the lower end of the cylindrical portion 12a may be widened or a hole may be provided therein, and each light emitting element 18 may be covered with this hole.

In the proximity switch 10, the light emitting elements 18 and the light guide member 12 constitute an operation display means, and each light emitting element 18 emits light in response to the detection operation of the detection object.

The light 19 emitted from each light emitting element 18 is guided to the front side through the inside of the cylindrical part 12a of the light guide member 12, and most of it is directly or by scattering, as shown by arrow B in FIG. As shown, it is emitted from the ring-shaped exposed portion 12b to the front side, and the negative portion is emitted from each side exposed portion 12c to the side side as shown by arrow C due to scattering or the like.

That is, the ring-shaped exposed portion 12b representing the area of the detection surface 6 and each side exposed portion 12c will shine.

In this case, a light diffusing material may be mixed in the ring-shaped exposed portion 12b, and in this way, the ring-shaped exposed portion 12b and each side exposed portion 12c can be made more efficient with a smaller number of light emitting elements 18. It can be illuminated evenly.

The fact that this ring-shaped exposed portion 12b lights up means that an operation display is performed to represent the area of the detection surface 6. Therefore, no matter which direction the detection object approaches, it will Unlike the proximity switch 2 in which the operation indicator light 8 is located at one point, the illuminated ring-shaped exposed portion 12b
Since all of the objects are not in the shadow of the object to be detected at the same time, even if the object to be detected is opaque, its operation display can always be visually recognized. Therefore, unlike the conventional proximity switch 2,
The mounting direction of the proximity switch 10 is not limited for this reason.

In addition, a ring-shaped exposed portion 1 is provided to represent the area of the detection surface 6.
2b is illuminated, the detection object 6 can be easily recognized even when adjusting the position relative to the detection object in a dark place. Therefore, adjustment work becomes easier.

Further, although it is not essential to provide the side surface exposed portion 12c, if it is provided as in this embodiment, the operation display can be viewed from the four side surfaces of the proximity switch 10, so that adjustment work can be carried out. This makes maintenance management, etc. easier.

Note that the ring-shaped exposed portion 12b of the light guide member 12 is
They do not necessarily have to be continuous as shown in Figure 1,
It may be intermittently ring-shaped.

The light guide member 12 also includes the ring-shaped exposed portion 12b.
Instead, as in the proximity switch 30 shown in FIG.
A planar exposed portion 12d is provided to cover the detection surface 6, and light 9 from the light emitting element 18 inside is emitted from the entire area of the planar exposed portion 12d to the outside, so that the entire planar exposed portion 12d is illuminated. You can do it like this.

In that case, a light diffusing material may be mixed into this planar exposed portion 12d, and in this way, the whole can be illuminated more uniformly with a smaller number of light emitting elements 18.

FIG. 5 is a plan view showing a proximity switch according to still another embodiment of the invention. FIG. 6 is a sectional view taken along the line ■-■ in FIG. 5. FIG. 7 shows the light guide member in FIG. 6, with (A) being a plan view thereof and (B)
is its side view, and (C) is its bottom view.

Mainly explaining the differences from the above embodiments, in this proximity switch 40, the light guide member 12 has a plate-like part 12e connected to the cylindrical part 12a as described above, and this plate The ring-shaped exposed portion 1 is provided at the peripheral edge of the shaped portion 12e.
2b and a side exposed portion 12c.

The central part of the front side of this plate-shaped part 12e is recessed into a conical shape with an apex angle of 90 degrees, thereby forming a reflective surface 12g there. A cylindrical projection 12f is formed on the back side of the reflective surface 12g for the purpose of supplementing the thickness of that portion, and a core 20a having a hole of the detection coil 20 is fitted into the projection 12f.

Further, a portion on the back side of the ring-shaped exposed portion 12b excluding a portion connected to the side exposed portion 12c is inclined at 45 degrees to form a reflective surface 12h there.

In this embodiment, one light emitting element 18 consisting of an LED is attached to the printed circuit board 16 at a position behind the reflective surface 12g at the center.

Therefore, in this proximity switch 40, the light emitting element 18
The light 19 from the center is reflected laterally as shown by the arrow on the reflective surface 12g at the center and guided laterally through the plate-like portion 12e, and most of it is reflected again at the reflective surface 12h at the periphery. As shown by the arrow B, it is emitted from the ring-shaped exposed portion 12b to the front side, and a part of it continues straight through the side exposed portion 12c and is emitted from each side exposed portion 12c to the side as shown by the arrow C.

In this way, unlike the proximity switch 10 described above, the ring-shaped exposed portion 12b and each side exposed portion 12c can be uniformly illuminated with one light emitting element 18. Therefore, the number of light emitting elements 18 can be reduced.

Moreover, since the reflective surfaces 12g and 12h are used, the light 19 from the light emitting element 18 can be efficiently emitted from the ring-shaped exposed portion 12b and each side exposed portion 12C, so that these exposed portions can be It can be made to shine brightly.

In addition, as shown by hatching in FIG. 5 or substrate-like hatching in FIG. metal film 4
2 may be attached to each reflective surface 1.
Since the reflectance at 2g and 12h is significantly improved, the ring-shaped exposed portion 12b and the side exposed portion 12c can be made to shine even brighter.

In addition, in this embodiment, a small interior 1 is provided around the reflective surface 12g.
2+ is provided, and part of the light 19 from the light emitting element 18 passes through it, so that part also shines in a ring shape, but this is not essential.

In addition, a shallow donut-shaped recess is provided on the front side of the plate-shaped portion 12e of the light guide member 12, and an opaque donut-shaped light shielding plate 41 is attached thereto, so that the light scattered within the plate-shaped portion 12e is exposed. Although the aesthetic appearance is improved by preventing leakage, it is not essential to do so.

In addition, when the metal film 42 is attached to each of the reflective surfaces 12g and 12h of the light guide member 12 as described above, the same metal film 42 is also attached to the surfaces of the cylindrical portion 12a, etc. of the light guide member 12. Then, the metal film 42 on the surface of the cylindrical portion 12a etc. may be electrically connected to the ground portion on the printed circuit board 16.

This will be explained in detail mainly with reference to FIG.
e, in addition to the exposed parts 12b and 12c, the cylindrical part 12a
It extends laterally from the printed base Ni16 and the lead wire 1.
Holding section 1212.4 for holding, etc. Thereafter, a leg portion 12m extending downward, and a protrusion 12n provided on the upper portion of the leg portion 12m.
, extending downward from the cylindrical portion 12a and connected to the printed circuit board 16.
The leg portions 12j, positioning protrusions 12, etc. are provided for holding, etc.

Metal 1i 142 is attached to the above-mentioned reflecting surfaces 12g and 12h in order to improve the reflectance of light, as shown by the grid-shaped hatching in FIG. 7, but this embodiment Now, in the same adhesion process, the cylindrical part 12
The same metal film 42 is attached to the surfaces (in this example, both the front and back surfaces) of the holding portion 129 and the holding portion 129, as shown by the usual hatching in FIG.

The electrical connection between the metal film 42 attached to the cylindrical portion 12a etc. and the ground portion on the printed circuit board 16 is made, for example, on the leg portion 1.
This can be easily done by applying a conductive adhesive between the ground portion of the printed circuit board 16 and the like.

However, the ring-shaped exposed portion 12b and the side exposed portion 12c
The metal film 42 is not attached to the surface of the substrate because it is necessary to guide light. The metal film 42 is not attached to both the front and back surfaces of the plate-shaped portion 12e from the viewpoint of preventing a decrease in detection sensitivity, and the metal film 42 is not attached to the reflective surface 12h near the surface of the resin 44 that is the exterior body. 42 to the ground part of the internal circuit is undesirable from the viewpoint of stability of operation, etc., a separation band 48 that does not allow the metal film 42 to be attached around the upper part of the cylindrical part 12a is provided as shown in the example shown in the figure. The width of this separation band 4B, which may be provided, does not need to be very large as long as it can provide an insulation distance.

If you try to attach the metal film 42 by vapor deposition or the like only to the surfaces of the reflective surfaces 12g and 12h, masking will be troublesome because you will have to cover the other areas, but if you try to attach it widely as described above, , since masking can be done in the minimum number of places necessary, masking becomes easier. Moreover, the metal M attached at the same time! 4
2 can be used for electrostatic shielding as follows.

In other words, in order to prevent malfunctions due to noise entering from the outside, conventional proximity switches cover the side of the detection coil with a shield ring and connect it to the ground of the internal circuit. However, in this embodiment, the metal film 42 attached to the cylindrical portion 12a that houses the detection coil 20 acts as an electrostatic shield, so when electrostatic shielding is used. This eliminates the need for a shield ring, which was previously required, and reduces the number of parts and assembly man-hours.

Further, if the metal film 42 is attached to parts other than the cylindrical part 12a as in this embodiment, the metal film 42 (of course, the metal film 42 attached to the cylindrical part 12a) is also attached to the printed circuit board 16. It also functions to some extent as an electrostatic shield for the electrical circuit (see FIG. 3) mounted there, so that the shielding effect can be improved without requiring any additional components.

Note that a shielding effect can be obtained by attaching the metal film 42 to at least one surface of the parts other than the reflective surfaces 12g and 12h, so it is optional whether the metal film 42 is attached to both sides or one side. It is best to choose one that is easy to mask.

Referring again to FIGS. 5 and 6, in the proximity switch 40 of this embodiment, the ring-shaped exposed portion 1 of the light guide member 12
2b and each side exposed portion 12c are exposed, the internal structure consisting of the light guide member 12, the detection coil 20, the printed L-5 board 16 on which electronic components are mounted, and the ends of the lead wires connected thereto. is integrally molded within an opaque and electrically insulating resin 44, and this resin 44 serves both as an exterior body in place of the case and as an internal filling resin.

However, the resin 44 is not inserted into the gap 52 between the projection 12f of the light guiding member 12 and the light emitting element 18 in order to allow the light 19 from the light emitting element 18 to pass therethrough.

The means for doing so will be described later. In addition, 44 in Figure 5
a is a mounting screw hole, and 15 is a rubber bush.

By doing the above, compared to a case where the internal structure is placed inside the case and filled with resin, as in the case of the proximity switch 10 shown in FIG. In addition, it is possible to reduce the size of the case by increasing the wall thickness of the case.

Furthermore, since the exterior body and the internal filling material are integrated, water resistance and moisture resistance are improved compared to a case in which the case is filled with resin.

Also, when filling the case with resin such as epoxy,
Mixing, defoaming, vacuum filling, etc. must be performed, making the process complicated and time-consuming, which increases assembly costs. However, when integral molding is adopted as described above,
Assembly is easier and assembly costs are lower.

An example of a method for manufacturing such a proximity switch 40 will be described with reference to FIG.

First, an internal structure is temporarily assembled using the light guiding member 12 as described above as an internal skeleton. That is, the detection coil 20 is housed in the cylindrical part 12a of the light guide member 12, and the
A printed circuit board 16 to which a light emitting element and electric circuit components are attached and a lead wire 14 is connected is placed on top of the printed circuit board 16 and connected to the leg portions 12L12m of the light guide member 12 and the positioning protrusion 12.
positioning and holding using, etc.

This printed circuit board 16 includes a cylindrical portion 12 of the light guide member 12.
It is preferable to provide holes 16a appropriately so that the resin to be injected later can sufficiently enter inside a.

Furthermore, if there is a gap 50 between the protrusion 12f of the light guide member 12 and the light emitting element 18 as described above, and there is a possibility that the opaque injected resin may flow into the gap 50, the gap 50 may be
It is preferable to fill the adhesive 52 with a transparent adhesive 52, such as an epoxy resin adhesive, in advance.

A mold 46 consisting of an upper mold 46a and a lower mold 46b
A cavity 46C having a shape corresponding to the outer shape of the resin 44 shown in FIG. into this cavity 46c, and using the light guiding member 12, more specifically, the leg portion 12j.
, 12m, the holding portion 12Q, the protrusion 12n, etc., are used to position it within the cavity 46c.

In that case, since no resin is injected into the surface of the light guide member I2 around the plate-shaped portion 12e, the light guide member I2 is made to tightly abut against the wall surface of the cavity 46C.

In this state, an opaque and electrically insulating resin to become the resin 44 described above is injected into the cavity 46C and injection molding is performed. As a result, the aforementioned proximity switch 4
0 is obtained.

In this case, the injected resin must be able to be injection molded at low pressure, have good fluidity, have low mold shrinkage (and have good adhesion with other resins, and be thermoplastic and have high productivity). It is preferable to use a good material. Specifically, it is preferable to use a liquid crystal polymer, polyarylate, PBT, etc.

Further, the light guide member 12 may also be formed of a transparent resin that is the same as or similar to the injected resin, and in this case, the adhesion between the light guide member 12 and the injected resin becomes better.

According to the manufacturing method described above, the internal structure can be temporarily assembled in advance before injection of the resin, and then operated as a proximity switch in a state close to that of a finished product to perform an operation test. Therefore, only those products that have passed the operation test can proceed to the next resin injection process, thereby significantly reducing the defective rate of finished products.

In addition, in order to prevent the parts that make up the internal structure from shifting when resin is injected, normally it is necessary to use adhesive or the like to temporarily hold them together, but as shown above, By using the light guiding member 12 as an internal skeleton, this becomes unnecessary.

In addition, normally an appropriate positioning member must be used to position the entire internal structure within the mold 46, but this becomes unnecessary by using the light guide member 12 itself for positioning as described above.

Therefore, from these points, the proximity switch 40 as described above
The assembly cost can be further reduced.

In any of the above embodiments, if the metal film 42 is not attached to the surface of the cylindrical portion 12a of the light guide member 12, that is, if the shielding function is not provided there, a substitute for the cylindrical portion 12a may be used. Appropriate legs may be provided.

Furthermore, in each of the above embodiments, the overall shape is a flat rectangular proximity switch, but the overall shape is not necessarily limited to this. It may also have a cylindrical shape or the like.

Further, the electric circuit housed inside is not necessarily limited to that shown in FIG. 3, and for example, a part thereof may be separated and provided outside. Alternatively, only the light emitting element 18 may be left as a detection head.

In addition to the high-frequency oscillation closest proximity switches such as those on each side described above, the present invention also provides a capacitive proximity switch that detects the approach of a detection object by a change in capacitance, and a capacitance type proximity switch that detects the approach of a detection object by a change in magnetic flux. Of course, it can also be applied to magnetic type proximity switches for detection.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

That is, the operation display means is constituted by the light emitting element and the light guide member as described above, and the operation display is performed to represent the area of the detection surface, so that the detection surface can be easily recognized even in a dark place. I can do it. Therefore, the installation and adjustment work of the proximity switch becomes easy.

Moreover, no matter which direction the object to be detected approaches, unlike in the case of conventional dot-shaped operation indicator lights, all of the exposed exposed parts of the light guiding member will not be in the shadow of the object at once. Therefore, even if the object to be detected is opaque, its operation display can always be visually recognized. Therefore, the degree of freedom in mounting the proximity switch increases in terms of direction.

In addition to the planar exposed part that covers the detection surface or the ring-shaped exposed part that surrounds the detection surface, the light guide member has an exposed part that is connected to the exposed part and is exposed on the side surface that intersects with the detection surface of the exterior body. When one or more side exposed portions are provided, the operation display can be viewed from the side, making adjustment work, maintenance, etc. of the proximity switch easier.

Furthermore, if the light guiding member is provided with a plate-like part, a reflective surface is provided in the central part and on the back side of the ring-shaped exposed part, and one light emitting element is provided behind the reflective surface in the central part. Since the ring-shaped exposed area and side exposed area can be illuminated uniformly with a single light-emitting element, the number of light-emitting elements is small, and since reflective surfaces are used, these exposed areas can be illuminated more brightly. be able to.

Also, if a metal film is attached to the surface side of each of the above reflective surfaces,
Since the reflectance there is greatly improved, each of the exposed parts can be made to shine even brighter.

In addition, when attaching a metal film to the reflective surface as described above,
If the same metal film is attached to the surface of the cylindrical part that houses the detection coil of the light guiding member and connected to the ground part of the internal electric circuit, this metal film will function as an electrostatic shield. Therefore, the shield ring that was conventionally required when performing electrostatic shielding is no longer necessary, and the number of parts and assembly man-hours can be reduced. Moreover, masking is easier than when a metal film is attached only to the reflective surface.

In addition, if the internal structure of the proximity switch and the end of the lead wire connected to it are integrally molded in an opaque and electrically insulating resin, a case is not required, which reduces the number of parts. and miniaturization can be achieved. Additionally, since the exterior body and internal filling material are integrated, water and moisture resistance is improved compared to a case in which the case is filled with resin.

Further, if integral molding is adopted as described above, assembly becomes easy and assembly cost is reduced.

In addition, when manufacturing a conductor-molded type proximity switch as described above, if the light guiding member is used to temporarily assemble the internal structure and position it in the mold, the distance between the parts constituting the internal structure may be reduced. Temporary fixing work to prevent misalignment is no longer required.
Moreover, since a positioning member within the mold is not required, the assembly cost of the proximity switch can be further reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a proximity switch according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line I-1 in FIG. FIG. 3 is a block diagram showing an example of the electrical circuit of the proximity switch of FIG. 1. FIG. 4 is a perspective view showing a proximity switch according to another embodiment of the invention. FIG. 5 is a plan view showing a proximity switch according to still another embodiment of the invention. FIG. 6 is a sectional view taken along the line ■-■ in FIG. 5. FIG. 7 shows the light guide member in FIG. 6, with (A) being a plan view thereof and (B)
is its side view, and (C) is its bottom view. Figure 8 shows
FIG. 2 is a cross-sectional view for explaining the manufacturing method according to the present invention. FIG. 9 is a perspective view showing an example of a conventional proximity switch. 4... Case (exterior body), 6... Detection surface, IO30
, 40... Proximity switch according to the embodiment, 12... Light guiding member, 12a... Cylindrical part, 12b... Ring-shaped exposed part, 12c... Side exposed part, 12d... Planar exposed portion, 12e... plate-like portion, 12g. 12h... Reflective surface, I6... Printed circuit board, 18.
...Light emitting element, 20...Detection coil, 42...Metal film, 44...Resin, 46...Mold. Figure 5

Claims (8)

[Claims] (1) A proximity switch that detects a detection object approaching a detection surface includes one or more light emitting elements that are housed inside an exterior body and emit light in response to the detection operation of the detection object, and a portion of which is located on the detection surface. What is claimed is: 1. A proximity switch comprising: a light guiding member that is exposed on the surface of the exterior body and that guides light from the light emitting element and emits the light from the exposed portion to the outside. (2) The light guide member has a planar exposed portion that covers the detection surface and one or more side surface exposed portions that are connected to the planar exposed portion and are exposed on the side surfaces that intersect with the detection surface of the exterior body.
Proximity switch as described. (3) The light guide member has a ring-shaped exposed portion surrounding the detection surface and one or more side surface exposed portions that are connected to the ring-shaped exposed portion and are exposed on a side surface that intersects with the detection surface of the exterior body. Proximity switch as described. (4) The light guiding member has a plate-shaped portion, and the ring-shaped exposed portion and side exposed portion are provided on the peripheral edge of the plate-shaped portion, and the central portion of the front side of the plate-shaped portion is recessed in a conical shape. The back side of the ring-shaped exposed portion is inclined to form a reflective surface there, and the reflective surface is formed at the back of the reflective surface at the center of the plate-shaped portion. One light emitting element is provided, whereby the light from this light emitting element is reflected by a reflective surface in the center, guided to the side through the plate-like part, and emitted from the side surface exposed part to the side surface side. 4. The proximity switch according to claim 3, wherein the light is reflected by a reflective surface on the back side of the ring-shaped exposed part and emitted from the exposed part to the front side. (5) The proximity switch according to claim 4, wherein a metal film is attached to the surface side of each of the reflective surfaces. (6) the light guiding member has a cylindrical portion connected to the plate portion, and a detection coil is provided within the cylindrical portion;
A metal film of the same type as that applied to each of the reflecting surfaces is also attached to the surface of this cylindrical part, and this metal film is electrically connected to a grounding part of an internal electric circuit. Proximity switch according to item 5. (7) With each of the exposed parts of the light guiding member exposed, the internal structure of the proximity switch and the ends of the lead wires connected thereto are integrally enclosed in an opaque and electrically insulating resin. The proximity switch according to any one of claims 1 to 6, which is formed by molding. (8) Temporarily assemble the internal structure using the light guide member as an internal skeleton, place the internal structure and the end of the lead wire connected to it in a mold, and use the light guide member. 8. The method of manufacturing a proximity switch according to claim 7, further comprising injecting an opaque and electrically insulating resin into the mold after positioning the internal structure within the mold.