JPH025545Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Field of the invention This invention relates to a photoelectric switch, and particularly relates to a mounting structure for a light emitting element and a light receiving element.

(b) Prior art and its problems In general, photoelectric switches include transmissive and reflective types. All of these photoelectric switches incorporate a light emitting element and a light receiving element.

Among these photoelectric switches, for example, a transmissive type is constructed by housing a light emitting element b, a light receiving element c, a printed circuit board d, etc. in a case a, as shown in FIG. This case a has a pair of storage protrusions f, f formed in the center of the upper surface of the rectangular main body part e to protrude upward, and a detection groove g is formed between the protrusions f. A printed circuit board d is installed on the main body part e, while a light emitting element b and a light receiving element c are erected on the printed circuit board d and provided in the storage convex part f.

Therefore, the light emitted from the light emitting element b is transmitted through the groove g.
The light is received by the light receiving element c through the groove g, and when a detection object is located in the groove g, the light is blocked and detected.

The light emitting element b and the light receiving element c in this photoelectric sensor have terminals j and k extending downward from the element bodies h and i, and the element bodies h and i are die-bonded or wire-bonded to a lead frame and then exposed to light. It was formed by coating it with a transparent epoxy resin or the like.

However, in the light emitting and light receiving elements b and c, conventionally, the terminals j and k were simply extended and connected to the printed circuit board d, which caused a problem that the heights were uneven. In particular, since the groove g of the case a needs to have a predetermined depth, the terminals j and k become long, resulting in so-called high-height mounting, making height adjustment difficult. Furthermore, although the light emitting surface of the light emitting element b and the light receiving surface of the light receiving element c need to face each other, there is a problem in that the optical axes do not coincide. Moreover, when inserting the case a, if the element bodies h and i are inclined, it is difficult to insert the case into the housing convex part f, and the terminals j and k may buckle.

In other words, the terminal j of the light emitting element b may buckle as shown in Fig. 2, the element bodies h and i may tilt downward and upward as shown in Fig. Thus, the element bodies h and i were tilted to the right and left sides, and the optical axes l and m did not coincide with each other.

Furthermore, if the optical axes l and m are misaligned, it cannot be corrected after the optical axis is housed in a case. Since it is necessary to prevent this misalignment, there is a problem in that automatic assembly is difficult and manual assembly is required.

(c) Purpose of the invention This invention was made in view of the above points, and is a photoelectric sensor in which the optical axes are always aligned by providing a sub-case through which the terminals of the light-emitting element and the light-receiving element pass. The purpose is to provide

(d) Structure and effect of the invention In order to achieve the above-mentioned purpose, this invention
A sub-case is installed on a printed circuit board within the case, and a guide protrusion that can be fitted into the storage protrusion is formed in this sub-case, and the light emitting element and light receiving element are mounted on the upper surface of the guide protrusion. A positioning part for positioning the main body is formed, and a guide hole through which the terminals of the light emitting element and the light receiving element pass is formed from the upper surface to the lower surface of the guide convex part,
The light emitting element and the light receiving element are arranged at predetermined positions.

Therefore, according to the photoelectric sensor of this invention,
By being positioned in the positioning part of the sub-case, the height of the light emitting element and the light receiving element is always constant, and at the same time, the element body does not tilt vertically, horizontally, etc., so the optical axes can be aligned accurately. Can be done.

Furthermore, since the terminals are covered by the sub-case, buckling and the like can be reliably prevented, and furthermore, the optical axes can be aligned simply by inserting and connecting the terminals to the printed circuit board.

Further, since the case can be easily inserted, automation of assembly can be promoted. In addition, since the characteristics of the product can be stably ensured, reliability can be improved.

(E) Description of Embodiments Hereinafter, embodiments of this invention will be described in detail based on the drawings.

As shown in FIGS. 5 and 6, 1 is a transmission type photoelectric switch, which includes a light emitting element 2 and a light receiving element 3.
are provided facing each other, and when an object or the like is located between both elements 2 and 3, the object is detected.

The light emitting element 2 and the light receiving element 3 are housed in a case 4 and are connected to a printed circuit board 5. This case 4 has two storage convex portions 4b, 4b formed in the center of the upper surface of a substantially rectangular main body portion 4a, projecting upwardly, and transparent windows 4c, 4c formed on opposing surfaces of both convex portions 4b, 4b. is formed, and the convex portion 4
The area between b is a detection groove portion 4d. In addition, 4e is a mounting hole for a panel etc., and 4f is a boss for caulking the back cover 4g.

The printed circuit board 5 is housed in the case main body 4a, various electronic components 6 are mounted thereon, and external terminals 7 are connected.

The light emitting element 2 and the light receiving element 3 include an element main body 2
Terminals 2b and 3b are configured to extend downward from a and 3a. Although not shown, the element bodies 2a and 3a are formed by die bonding and wire bonding a chip to a lead frame.
It is coated with a light-transmissive epoxy resin or the like. The element bodies 2a, 3a are installed at the top of the case storage convex portion 4b, and the lower ends of the respective terminals 2b, 3b are inserted and connected to the printed circuit board 5.

A sub-case 8 is housed in the case 4, and this sub-case 8 has two guide protrusions 8a,
8a and a connecting portion 8b that connects both convex portions 8a, 8a at their lower ends are integrally molded from resin. This sub-case 8 is designed to be installed on the printed circuit board 5, and a recess 8c for storing the electronic component 6 is formed in the connecting portion 8b.

The guide convex portion 8a is formed to be able to fit into the storage convex portion 4b, and the upper front surface is formed with a tapered inclined guide surface 8d, and the lower portion is formed in approximately the same shape as the horizontal cross section of the storage convex portion 4b. There is. This guide surface 8d is in contact with the lower end corner of the storage projection 4b and guides the guide projection 8a to the storage projection 4b, while the back and front lower portions of the guide projection 8a are fitted into the storage projection 4b. This is the positioning part.

Furthermore, a guide hole 8e for the terminals 2b, 3b is formed in the guide protrusion 8a from the upper surface to the lower surface. This guide hole 8e is inserted into the element body 2 from the upper end.
a, a positioning part 8f into which 3a is inserted, an inclined part 8g whose cross section becomes narrower toward the lower end, and terminals 2b, 3.
Fitting portions 8h having a cross section substantially the same as that of the terminals b are formed in sequence, and the lower ends of the terminals 2b and 3b protrude slightly.

Next, the assembly operation of this photoelectric sensor 1 will be explained.

First, in addition to the light emitting element 2 and the light receiving element 3, a case 4, a printed circuit board 5, and a subcase 8 are formed separately.

Each terminal 2b, 3 of the light emitting and light receiving elements 2, 3
b into the guide hole 8e of the sub-case 8, and the lower end protrudes slightly. At that time, the element bodies 2a, 3b
fits into the positioning portion 8f.

Then, at the same time as this sub-case 8 is installed on the printed circuit board 5, the lower ends of the protruding terminals 2b and 3b are inserted into the printed circuit board 5 and soldered from the back side. As a result, both elements 2 and 3 face each other with the same height, and their optical axes match.

Subsequently, when this printed circuit board 5 is inserted into the case 4, the lower end corner of the storage convex portion 4b is aligned with the guide surface 8.
The guide convex portion 8a is guided to the storage convex portion 4b in contact with d. At this time, since the element bodies 2a and 3b are positioned by the positioning portion 8f, the occurrence of tilting or the like is prevented.

When the printed circuit board 5 is completely inserted into the case 4, the guide convex portion 8a fits into the housing convex portion 4b, and the light emitting element 2 and the light receiving element 3 are installed at predetermined positions within the housing convex portion 4b.

Finally, the back cover 4f is attached to complete the assembly.

In this embodiment, a transmission type photoelectric sensor 1 was explained in which a light emitting element 2 and a light receiving element 3 were placed facing each other. However, this invention can be applied to a reflection type photoelectric sensor in which both elements 2 and 3 are arranged side by side with both elements 2 and 3 facing forward. May be applied.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a conventional photoelectric sensor, FIGS. 2 to 4 show the installation state of a conventional light emitting element and light receiving element, and FIGS. 2 and 3 are schematic side views of both elements, and FIGS. 4 is a schematic plan view of the same, FIGS. 5 and 6 show an embodiment of the invention, FIG. 5 is a longitudinal sectional view of the photoelectric sensor, and FIG. 6 is an exploded side view of the photoelectric sensor partially shown in section. be. 1... Photoelectric sensor, 2... Light emitting element, 3... Light receiving element, 2a, 3a... Element body, 2b, 3b...
...Terminal, 4...Case, 4a...Main body, 4b...
...Storage protrusion, 5...Printed circuit board, 8...Sub case, 8a...Guide protrusion, 8d...Guide surface,
8e...Guide hole.

Claims (1)

[Claims for Utility Model Registration] (1) A light-emitting element, a light-receiving element, and a printed circuit board are housed in a case, and the light-emitting element and light-receiving element are configured by extending terminals from the element body, and the element body is connected to the case. In the photoelectric sensor, each terminal is connected to the printed circuit board, and a sub-case is installed in the printed circuit board within the case, and the sub-case is installed in the storage convex part. A guide convex part that can be freely fitted is formed, and a positioning part for positioning the element bodies of the light emitting element and the light receiving element is formed on the upper surface of the guide convex part, and the terminals of the light emitting element and the light receiving element pass through. A photoelectric sensor characterized in that a guide hole is formed from the upper surface to the lower surface of the guide convex portion, and the light emitting element and the light receiving element are positioned at predetermined positions. (2) The photoelectric sensor according to claim 1, wherein the guide convex portion is formed with an inclined guide surface, and a corner portion of the storage convex portion of the case is in contact with the guide surface.