JPH0722838Y2 - Photoelectric sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photoelectric sensor having a case structure.

[Conventional technology]

Conventional photoelectric sensors are classified into transmission type, diffuse reflection type and recursive reflection type. However, in reflection type photoelectric sensors, it is necessary to provide a light emitting element and a light receiving element on the front surface of the case. Because of the separated shape, the light projecting element or the light receiving element is arranged in front of the switch. Therefore, in order to focus the light of these photoelectric elements in a predetermined area or to collect the reflected light, a lens is often provided on the front surface of the case, but each of them has a dedicated case for each type of switch. A lens is attached to the front surface of the case, and the light emitting / receiving element is fixed in the case.

[Problems to be solved by the device]

However, according to such a conventional photoelectric sensor, a case is required for each type of photoelectric sensor. Therefore, since the number of types of parts increases and the number of molds also increases, there is a drawback that not only the price increases but also the management becomes complicated. When a common case is used in the transmission type photoelectric sensor in order to be shared with the case of the reflection type photoelectric sensor, the lens is largely deviated from the center of the photoelectric sensor, which is unfavorable from an aesthetic point of view and disadvantageously reduces the commercial value. there were. There is also a drawback that the optical axis position is not clear when an optical element that does not require a lens is attached.

The present invention has been made in view of the above problems of the conventional photoelectric sensor. It is an object of the present invention to share a photoelectric sensor case for each type without separating them and improve the lens balance. Subject.

[Means for Solving the Problems]

The present invention is a photoelectric sensor having at least one of a light projecting element and a light receiving element, wherein an external circular Fresnel lens having a central portion of the lens formed at a predetermined position, and the Fresnel lens lateral to the Fresnel lens. It is characterized in that a lens plate having an arcuate line having substantially the same outline is attached to the opening of the case.

[Action]

According to the present invention having such characteristics, the Fresnel lens portion is formed at a predetermined position of the lens plate provided on the front surface of the case, and the lens formed on the side of the lens on the central portion side of the lens plate is formed. An arcuate line having the same outer shape as that of is formed. The photoelectric element of the transmissive photoelectric sensor is arranged at the focal position of the Fresnel lens of the lens plate to focus the irradiation light in a predetermined direction or to collect and receive the light obtained from the predetermined direction.

[Effect of device]

Therefore, according to the present invention, it is possible to configure the projector or the light receiver of the transmissive photoelectric sensor by sharing the case or frame of the reflective photoelectric sensor. In the reflection type photoelectric sensor, a lens plate having two lenses formed close to each other is used to be mounted on the front surface of the case. In the transmission type photoelectric sensor, the lens plate according to the present invention, that is, the Fresnel lens and the same shape as the lens plate. A photoelectric sensor is formed by using a lens plate having an arc line. Also in this case, since the Fresnel lens provided on the front surface of the case has the light projecting element provided at the focal position of the lens having the original lens effect, the light can be focused or condensed in a predetermined region. Further, in the reflection type photoelectric sensor, the photoelectric sensor may be configured by using this lens plate. In this case, an arcuate line is provided adjacent to the Fresnel lens. Therefore, even when the element that requires the lens effect and the element that does not need the lens effect are mounted in the case, the positions of the respective optical axes can be clearly recognized from the outside, and the mounting can be facilitated.

[Explanation of Examples]

1A to 1C are front views showing the structure of a lens plate mounted in front of a photoelectric sensor according to an embodiment of the present invention,
FIG. 2 is a vertical sectional view of the center and a rear view, FIG. 2 is a vertical sectional view of a photoelectric sensor according to the present invention using this lens plate, and FIG. As shown in these figures, the photoelectric sensor according to the present embodiment has a case body 1 as its housing. The case body 1 is a case-shaped member having an open top, and a rectangular opening 1a for attaching a lens plate is formed on the front surface, and a screw groove for inserting a cable obliquely downward is formed on the lower surface of the rear surface thereof. 1b is formed. The upper side wall of the case 1 is formed in a step shape, and an annular groove 2 is formed around the outside of the opening with a predetermined angle to the bottom surface. A pair of openings 1c and 1d are formed on the front surface of the case body 1 at the portion projecting above the groove 2. The lens plate 3 shown in FIG. 1 is attached to the opening 1a on the front surface of the case body 1. The lens plate 3 has curved portions 4a, 4b on the back side centered on a position P1 slightly displaced from the center position thereof.
The Fresnel lens 4 is formed. The Fresnel lens 4 is a lens having a circular outer shape, and an arcuate groove 5 is formed on the back surface of the Fresnel lens 4 in the center side of the lens plate 3 so as to overlap with the Fresnel lens 4, as shown in FIG. 1 (c). The groove 5 is an arc-shaped line having substantially the same shape as the groove formed by the Fresnel lens 4, and its center is located on the center line in the longitudinal direction of the lens plate 3. The frame 6 is inserted into the case body 1. Frame 6 has an opening 6a on the front
Is provided and element holders 6b and 6c are formed inside thereof. The frame 6 has the element holder 6b so that the center of the Fresnel lens 4 coincides with the element holder 6c and the center of the arcuate groove 5 coincides with the element holder 6b when the frame and the lens plate 3 are attached to the case body 1. It is assumed that the positions of 6c are specified.

Assuming that the present embodiment is the light projecting unit of the transmission type photoelectric sensor,
A light projecting element such as an infrared light emitting diode is attached only to the element holder portion 6c. The upper portion of the opening 6a is cut out in an E shape to provide a pair of elastic protrusions 6d and 6e. Frame 6
As shown in FIG. 2 or FIG.
Install 6f. A printed circuit board 7 having an outer shape corresponding to the shape of the frame 6 is attached from the side of the frame 6. As shown in FIG. 3, the terminal block portion 6f of the frame 6 is provided with terminal washers 8a, 8b and 8c to 8e each having a square shape and projecting downward or laterally, one end of which is connected to the printed circuit board 7. ing. A drive circuit for driving the light projecting element 9 is mounted on the printed circuit board 7, and power is supplied from the terminal block portion 6f. The printed circuit board 7 is also integrally formed with printed circuit boards 10a and 10b parallel to the upper surfaces of the case body 1 and the frame 6, and an operation display element 11, for example, a light emitting diode is mounted on the upper part of the printed circuit board 10a and 10b via a spacer 12. .
A body cover 13 is attached to the upper opening of the case body 1. As shown in FIG. 2, the main body cover 13 is a substantially transparent member, the lower surface of which is open, and is attached so as to come into contact with the groove 2 provided in the case main body 1 and tighten the O-ring 14. As shown in FIG. 2, projections 13a, 13b and 13c, 13d which engage with the upper openings 1c, 1d of the case body 1 are provided on the inner front surface of the body cover 13. A hexagon nut 17 is attached below the case body 1 via an annular seal rubber 15 and a washer 16.

As described above, in the present embodiment, the projector of the transmissive photoelectric sensor is shown, but the circuit on the printed circuit board is replaced with a light receiving element such as a photodiode as the light projecting element and a detection circuit for detecting the presence or absence of an object by this output. Then, the light receiver of the transmission type photoelectric sensor can be configured with the same configuration. Also, for photoelectric sensors of diffuse reflection type or recursive reflection type, light emitting / receiving elements are attached to the element holder portions 6b and 6c, respectively. At this time, for example, when a lens is not required on the light receiving element side, the light receiving element is mounted on the element holder 6b side. By doing so, the center position of the optical axis can be recognized as the center position of the arc-shaped line when viewed from the outside, and thus the photoelectric sensor can be easily set. In addition, as shown in FIGS. 4 (a) and 4 (b), the front surface of the case has two Fresnel lenses 21a and 21b on the central axis.
You may attach the lens plate 22 which has. In this way, the reflection type photoelectric sensor can be constructed by using the same case and frame only by changing the lens plate and the electronic circuit section on the front surface of the case.

[Brief description of drawings]

1 (a) is a front view of a lens plate according to an embodiment of the present invention, FIG. 1 (b) is a central longitudinal sectional view thereof, FIG. 1 (c) is a rear view, and FIG. 2 is this lens plate. FIG. 3 is a vertical cross-sectional view of a projector of a transmission type photoelectric sensor constructed by using FIG. 3, FIG. 3 is an assembly configuration diagram thereof, and FIGS. 4 (a) and 4 (b) are front and side views of a lens plate used for the reflection type photoelectric sensor, respectively. It is a figure. 1 …… Case body, 2,5 …… Groove, 3 …… Lens plate, 4,21
a, 21b …… Fresnel lens, 6 …… frame, 6b, 6c ……
Element holder part, 7 ... Printed circuit board, 9 ... Projector element,
13 …… Main body cover

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ichiro Kondo, Inventor, Tateishi Electric Co., Ltd., No. 10, Hanazono Dodo-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture (56) References: 60-133546 (JP, U) 59-115535 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A photoelectric sensor having at least one of a light projecting element and a light receiving element, wherein an outer circular Fresnel lens having a central portion of the lens formed at a predetermined position, and the Fresnel lens lateral to the Fresnel lens. A photoelectric sensor, characterized in that a lens plate having an arcuate line having substantially the same outline is attached to an opening of a case.