JPS6372020A - Photoelectric switch - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a reflective photoelectric switch having a sensing surface on the front surface and having an ultra-compact structure.

[Summary of the invention]

In the present invention, the chips of the light receiving element and the light emitting element are mounted in tandem directly along the longitudinal axis of the case on the substrate on which the detection circuit section inside the case is mounted. Then, the light from the light emitting element chip is changed into an optical path along the longitudinal axis of the case by the first or second reflecting means, and the reflected light is given to the light receiving element chip by the other reflecting means, so that the light emitting and receiving light path is changed. are matched. Therefore, it is possible to make an ultra-small photoelectric switch with the detection surface set in the front direction.

[Prior art and its problems]

(Prior Art) Conventional photoelectric switches include a first type photoelectric switch that has a sensing area on the longitudinal front surface of a thin case, and a second type photoelectric switch that has a sensing area on the top surface of the case. There is.

Figure 5 shows the first type of conventional reflective photoelectric switch.
A transparent window 3a for the light receiving element 2 is provided in the front opening of the case 1.
A transparent window 3b for the light projecting element 4 is provided. The light-receiving element 2 and the light-emitting element 4 are held in element holders 5a and 5b to face the transparent windows 3a and 3b, respectively, and a printed circuit board 7 on which a detection circuit section 6 is mounted is mounted in the center of the case 1. It is provided.

On the other hand, as shown in Fig. 6, the second
In the type of reflective photoelectric switch, for example, a printed circuit board 10 on which a detection circuit section 9 is mounted is held in a pair of cases 8a, and a light receiving element 11 and a light emitting element 12 are attached. Lenses 13a and 13b are provided in the front opening of the case 8b so as to face the light receiving element 11 and the light emitting element 12, respectively.
is provided.

(Problem to be Solved by the Invention) However, in the first type of photoelectric switch, the thickness of the photoelectric switch is limited by the outer diameters of the light emitting element and the light receiving element, so it is not possible to make it very thin and compact. Ta. Furthermore, in order to align the optical axes of the light emitting and receiving element and the lens, an element holder and the like are required to fix the light emitting element, the light receiving element and the lens. Therefore, the structure of the photoelectric switch becomes complicated, and the number of man-hours required to assemble the photoelectric switch increases, reducing work efficiency. As a result, there was a problem in that the price of the photoelectric switch increased.

Since the photoelectric switch of type 2 has the light emitting and receiving elements mounted on the same printed circuit board as the detection circuit, it is necessary to ensure the height of the light emitting and receiving elements, and the light emitting and receiving elements are installed in the translucent window. In order to focus the light onto the lens, it is also necessary to ensure the focal length.

Therefore, this type of photoelectric switch also has the problem that it cannot be made very thin and compact.

[Purpose of the invention]

The present invention has been made in view of the problems of the conventional photoelectric switch, and a technical object of the present invention is to miniaturize the photoelectric switch more than the conventional one while performing front-side detection.

[Structure and effects of the invention]

(Means for Solving the Problems) The present invention is a reflective photoelectric switch having a detection surface on the front surface, which includes a cylindrical case and a detection circuit provided inside the case, as shown in FIG. A board on which is mounted, a light emitting element and a light receiving element chip mounted directly on the board in a column along the longitudinal axis of the case, and a chip mounted at a predetermined angle from the longitudinal axis of the case provided at the front inside the case. a first reflecting means installed at an angle and reflecting a part of the light along the axis and transmitting the other part; a second reflecting means installed at an inclined angle and reflecting a part of the light along the axis; The chips are arranged to face each other, and the other of the light projecting element and the light receiving element chip is arranged in the second reflecting means to face each other.

(Function) According to the present invention having such characteristics, the light from the light projecting element chip is reflected in the direction along the longitudinal axis of the case by the first or second reflecting means, and the reflected light is directed to the other side. The light is reflected by the reflecting means and applied to the light receiving element chip.

Then, a part of the light given to the first reflection means from the second reflection means arranged at the rear of the case is passed through as is, so that the optical paths of the light emitting and receiving parts are made to coincide, and the front surface of the case is used as a detection surface. That's what I do.

(Effects of the Invention) Therefore, according to the present invention, since the small-sized photoelectric element chip itself is directly mounted on the substrate, there is no need for fixed parts such as an element holder, and an ultra-small photoelectric switch can be obtained.

Furthermore, the chips of the light receiving element and the light emitting element are directly mounted in tandem on the substrate along the longitudinal axis of the case, and the light from the light emitting element chip is reflected along the longitudinal axis of the case by the first reflecting means. The reflected light is reflected and the reflected light is applied to the light receiving element chip by the second reflecting means, so that the optical paths of the transmitted and received light are made to coincide with each other. Therefore, it is possible to make an ultra-small photoelectric switch with the detection surface set in the front direction.

Furthermore, an element holder or the like is not required, the light-transmitting window can be used for light reception, the number of parts of the photoelectric switch is small, assembly is easy, and it can be manufactured at low cost.

[Explanation of Examples]

FIG. 1, FIG. 2, and FIG. 3 are a vertical sectional view, a horizontal sectional view, and an A of the photoelectric switch according to an embodiment of the present invention, respectively.
-A cross-sectional view. In these figures, the case 21 of the photoelectric switch according to this embodiment is composed of an upper case 21a and a lower case 21b. Lower case 21.
A printed circuit board 22 is fixed inside b. Pudding)
A light-receiving element chip 23 and a light-emitting element chip 24 are mounted on the five-plate 22 from the front of the case along the longitudinal axis of the case, and light from the light-emitting element chip 24 is mounted between these chips 23 and 24. A light shielding wall 25 is provided to prevent the light from directly irradiating the light receiving element chip 23. Light receiving element chip 23. The light emitting element chip 24 is directly fixed to the wiring pattern on the printed circuit board 22 by wire bonding, and is connected to the wiring pattern formed on the printed circuit board 22 by wire bonding. Further, the light receiving element chip 23 and the light emitting element chip 24 are covered with transparent resins 26a and 26b. A planar half mirror 27, which is a first reflecting means, is mounted on the inner surface of the upper case 21a, facing the light-receiving element chip 23 and tilted at an angle of, for example, 45@ with respect to the longitudinal axis of the case.

Further, behind it, a plane mirror 28 serving as a second reflecting means is mounted opposite to the light projecting element chip 24 and inclined at an angle of, for example, 45 degrees with respect to the longitudinal axis of the case. The half mirror 27 and the plane mirror 28 are mounted so that their optical axes coincide with the optical axis of a lens 29 provided on the front surface of the case 21.

A detection circuit section 30 is mounted on the printed circuit board 22 behind the light emitting and receiving element chip 24 for driving the light emitting element chip 24 and detecting an object based on the light reception signal from the light receiving element chip 23. An indicator light 31 is provided at the rear of the printed circuit board 22, and a cord 32 for transmitting signals to the outside is connected.

When the photoelectric switch configured in this manner is operated, the light emitted from the light projecting element chip 24 is reflected by the plane mirror 28 and then transmitted through the plane half mirror 27 and then passed through the lens 29.
The detection area is irradiated with a nearly parallel beam of light. When an object passes through the detection area, the light reflected by the object is condensed by a lens 29, reflected by a half mirror 27, and then applied to a light receiving element chip 23.

As described above, in this embodiment, the light receiving element chip 23 itself and the light emitting element chip 24 themselves, which are small in shape, are directly mounted on the printed circuit board. The light from the light emitting element chip is reflected by the reflecting means along the longitudinal axis of the case, and the reflected light is applied to the light receiving element chip by the reflecting means, so that the optical paths of the emitted and received light are aligned. Therefore, it is possible to make an ultra-small photoelectric switch with the front side serving as the detection surface.

In this embodiment, a flat half mirror 27 and a flat mirror 28 are attached to the inner surface of the upper case 21a as reflecting means.
As shown in the longitudinal cross-sectional view of Fig. 4, a flat half mirror 27
It is also possible to use a curved half mirror 33 instead, and a concave mirror 34 instead of the plane mirror 28. In this case, it is possible to construct a photoelectric switch with relatively strong directivity without using a condensing lens on the front surface of the case.

Further, in this embodiment, the light receiving element chip 23 was provided facing the first reflecting means, and the light projecting element chip 24 was provided facing the second reflecting means. The optical element chip 24 may be provided, and the light receiving element chip 23 may be provided opposite the second reflecting means.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a photoelectric switch according to the present invention, FIG. 2 is a cross-sectional view thereof, and FIG.
′! It is an fIA sectional view. FIG. 4 is a vertical cross-sectional view of a photoelectric switch according to another embodiment of the present invention, FIG. 5 is a vertical cross-sectional view of an example of a conventional reflective photoelectric switch, and FIG. 6 is a vertical cross-sectional view of an example of a conventional reflective photoelectric switch. FIG. 1, 8a, 8b, 21---Case 2.11---Light receiving element 4.12---Light projecting element 5a. 5b...-Element holder 6.9.30-----1 detection circuit section 7, 10.22--Printed circuit board 13 a, 13 b, 29--1--
Lens 21a---Upper case 21b--
−・・−Lower case 23・−1・Photodetector chip
24---Light emitter chip 25--- Light shielding wall
26a, 26b・・・・・Transparent resin 27～−1・−・
Planar half mirror (first reflecting means) 28...
Single plane mirror (second reflecting means) 33------
−Curved half mirror (first reflecting means) 34・−・−
-Concave mirror (second reflecting means) Patent applicant Tateishi Electric Co., Ltd. agent Patent attorney Yoshiki Okamoto (and one other person) Fig. 1 21 - Case 22 - Printed circuit board 23・---Kiti "r +, yp24---
---Anti-nine anti-Japanese 1 story 27------・Hayakokuran half mirror- 28-----・2015 2nd figure 3rd figure 4th figure

Claims (5)

[Claims] (1) A cylindrical case, a board provided in the case and mounted with a detection circuit, and light projecting elements mounted directly on the board in a vertical line along the longitudinal axis of the case; a first light-receiving element chip, which is provided at the front inside the case and is attached at a predetermined angle from the longitudinal axis of the case, and which reflects a part of the light along the axis and transmits the other part; a second reflecting means provided behind the first reflecting means and attached at a predetermined angle from the longitudinal axis of the case, and reflecting a part of the light along the axis; The first reflecting means has one of the light receiving element chip and the light emitting element chip facing the second reflecting means,
A photoelectric switch characterized in that the other of the light emitting element and the light receiving element chip is disposed in the reflecting means so as to face each other. (2) The photoelectric switch according to claim 1, wherein the first reflecting means is a flat half mirror. (3) The photoelectric switch according to claim 1, wherein the first reflecting means is a curved half mirror. (4) The photoelectric switch according to claim 1, wherein the second reflecting means is a plane mirror. (5) The photoelectric switch according to claim 1, wherein the second reflecting means is a concave mirror.