JPH065908A - Photo-interrupter - Google Patents

Abstract

(57) [Abstract] [Purpose] The structure is such that even if the light emitting element and the light receiving element are mounted on the printed circuit board by SMT in the same direction, the light receiving element can receive the light from the light emitting element. Photo-interrupter. [Structure] 1 is a housing made of an infrared ray transmissive resin, which has a pair of protrusions 2 and 3 facing each other at its upper end, and inclined surfaces 4 and 5 are symmetrically provided on one side surface of the protrusions. Mounting holes 6 are formed at predetermined positions on the surface, mounting portions 7 are provided on both sides, and 8 is an S arranged inside the housing 1.
In the MT printed circuit board, a protrusion 9 is provided at the upper end corresponding to the protrusions 2 and 3, and a lead 10 is connected to the lower end. In addition, the convex portion 9 provided on the printed circuit board 8 so as to face the inclined surfaces 4 and 5 of the housing 1.
A light emitting element 11 and a light receiving element 12, which are chip parts, are attached to each of them, and a surface facing the light emitting element and the light receiving element is a mirror surface in an attachment hole 6 formed in the inclined surfaces 4 and 5 of the housing 1. Then, the reflecting plate 13 is attached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo interrupter, and more particularly to a structure of a reflection plate in an optical path.

[0002]

2. Description of the Related Art The conversion of light into electricity or the conversion of electricity into light is collectively called photoelectric conversion, and a photoelectric conversion element having a light emitting portion and a light receiving portion which are electrically insulated and coupled by light is called an optical conversion element. It is called a coupling element, and the optical coupling element is roughly classified into a photo coupler, a photo interrupter, and a photo sensor. In any element, a combination of an infrared light emitting diode as a light emitting portion and a silicon phototransistor as a light receiving portion is generally used.
As shown in FIG. 3, the photointerrupter, which is an optical coupling element, has a light emitting portion 14 and a light receiving portion 15 opposed to each other in a pair of protrusions provided at a predetermined interval on the upper end of a housing 16. It has a structure that can detect objects located between the protrusions through the transmission holes 17 formed on the surfaces of the protrusions facing each other. It is used in intended devices. In the conventional photo interrupter, since the light emitting section 14 and the light receiving section 15 face each other, a method of mounting discrete components, which are the light emitting element and the light receiving element, on the printed wiring board 18 is generally adopted. There is. In order to mass-produce these devices at a low cost, a method using SMT (surface mounting technology) in which a chip component element is mounted on a printed board and a reflow soldering process is performed is excellent. However,
In the method using the SMT, the chip parts, which are the light emitting element and the light receiving element, are mounted at the positions facing the same direction on the printed circuit board. Therefore, in this structure, the light receiving section directly receives the light from the light emitting section. There is a problem that can not be done.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a method using SMT, a light emitting element and a light receiving element mounted in the same direction on a printed circuit board. The present invention provides a photointerrupter having the same structure as that of the light emitting portion and the light receiving portion facing each other in the state.

[0004]

In order to solve the above-mentioned problems, the present invention comprises a pair of protrusions at the upper end portion which face each other with a required space, and one side surface of the protrusion has an inclined surface. And a housing made of infrared-transparent resin in which mounting holes are formed at predetermined positions on the same inclined surface, and projections corresponding to the projections on both sides of the upper end are provided in the housing. The SMT printed circuit board, the light emitting element and the light receiving element respectively mounted on the convex portion of the printed circuit board so as to face the inclined surface of the housing, and the mounting holes formed on the inclined surface of the housing. The present invention provides a photo interrupter characterized by comprising a light reflector and a reflector whose surface facing the light receiver is a mirror surface.

[0005]

With the above construction, in the photo interrupter according to the present invention, the light emitted from the light emitting element is reflected by the reflecting plate attached to one inclined surface, and this reflected light is projected on one projection of the housing. Through the wall of the housing, passes through the outside of the housing, and again through the wall of the other protruding part of the housing, and is reflected by the reflector installed on the other inclined surface. The reflected light is received by the light receiving element. Therefore, even if the light emitting element and the light receiving element are mounted on the printed circuit board at positions facing in the same direction, the light receiving element can receive the light from the light emitting element.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a perspective view of an embodiment of the photo interrupter according to the present invention, and FIG. 2 is a cross-sectional view of a main part of the embodiment of the photo interrupter according to the present invention.
2A is a plan sectional view of a main part, and FIG. 2B is a side sectional view of the main part. In the figure, reference numeral 1 denotes a housing made of an infrared-transparent resin, which is provided with a pair of protrusions 2 and 3 facing each other at an upper end thereof, and inclined surfaces 4 and 5 are symmetrically provided on one side surface of the protrusion. Mounting holes 6 are formed at predetermined positions on the surface, and mounting portions 7 are provided on both sides. Reference numeral 8 denotes an SMT printed circuit board arranged in the housing 1, which corresponds to the protruding portions 2 and 3. A protrusion 9 is provided at the upper end, and a lead 1 is provided at the lower end.
0 is connected. Further, a light emitting element 11 and a light receiving element 12, which are chip parts, are attached to the convex portion 9 provided on the printed circuit board 8 so as to face the inclined surfaces 4 and 5 of the housing 1, respectively. A reflector 13 having a mirror surface on the surface facing the light emitting element and the light receiving element in the mounting holes 6 formed in the inclined surfaces 4 and 5 of the housing 1.
Install. The reflection plate 13 is attached to the attachment hole 6 by inserting the protruding mirror surface side into the attachment hole 6 and adhering the flange portion to the inclined surfaces 4 and 5 of the housing. Although the external shape of the reflection plate is illustrated as a circle, the same effect can be expected if the reflection plate has a rectangular shape. Regarding the path of the light, first, the light emitted from the light emitting element 11 is reflected by the inclined surface 4, the reflected light passes through the wall surface of the protrusion 2 of the housing 1, passes through the outside of the housing 1, and again the housing 1 The light transmitted through the wall surface of the protruding portion 3 and reflected by the inclined surface 5, and the light reflected by the inclined surface 5 is received by the light receiving element 12. Since the reflection plate 13 can be attached to the attachment holes 6 formed on the inclined surfaces 4 and 5 of the housing 1 from the outside, the inside of the housing can have a simple structure. It is possible to mold the housing without using. Further, in the housing made of the infrared transmissive resin, the cost of the used member can be reduced by using the member made of the infrared transmissive resin only in the portion which becomes the light path. Also, in the reflector,
The same effect can be expected if the mirror surface is a concave surface that has a lens effect.

[0007]

As described above, in the photo interrupter according to the present invention, the light emitted from the light emitting element is reflected by the reflecting plate attached to one inclined surface, and the reflected light is reflected by one of the housings. Through the wall surface of the protrusion,
It passes through the outside of the housing and again passes through the wall surface of the other protruding part of the housing and is reflected by the reflecting plate attached to the other inclined surface, and the reflected light is received by the light receiving element. Even if the elements are mounted in the same direction on the printed circuit board, the light receiving element can receive the light from the light emitting element. Therefore, the method using SMT can be mass-produced at low cost. You can do it.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the structure of a photo interrupter according to the present invention.

FIG. 2 is a cross-sectional view of essential parts of an embodiment of the structure of the photo interrupter according to the present invention.

FIG. 3 is a main-portion cross-sectional view of an example of a structure of a conventional photo interrupter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Projection part 3 Projection part 4 Sloping surface 5 Sloping surface 6 Mounting hole 7 Mounting part 8 Printed circuit board 9 Convex part 10 Lead 11 Light emitting element 12 Light receiving element 13 Reflector plate

Claims (3)

[Claims] 1. A pair of protrusions, which are opposed to each other with a required space at the upper end, are provided with inclined surfaces symmetrically on one side surface of the protrusions, and mounting holes are provided at predetermined positions on the inclined surfaces. A housing made of infrared-transparent resin, and projections corresponding to the projections on both sides of the upper end, the printed circuit board for SMT disposed in the housing and the inclined surface of the housing facing each other. A light emitting element and a light receiving element respectively mounted on the convex portions of the printed circuit board, and a reflector having a mirror surface on the surface facing the light emitting element and the light receiving element respectively mounted on the mounting holes formed on the inclined surface of the housing. A photo interrupter characterized by comprising. 2. The photo interrupter according to claim 1, wherein an infrared transparent resin is used only in a portion of the housing that serves as a light path. 3. The photo interrupter according to claim 1, wherein a mirror surface of the reflector is a concave surface having a lens effect.