JPH02834Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a photoelectric switch that receives an optical signal and derives a detection signal, and particularly relates to the structure of the light receiving portion of the photoelectric switch.

[Conventional technology]

A light receiving element (photo diode) of a photoelectric switch has a function of deriving a detection signal by receiving an optical signal from a light emitting element. Therefore, it is susceptible to noise, which is a disturbance wave that mixes into the optical signal and interferes with its normal reception or processing. Therefore, the light-receiving section provided with the light-receiving element generally uses a flexible substrate in which the back surface of a polyimide resin is entirely coated with copper foil to block the influence of noise.

As shown in FIG. 3, a light receiving section 11 of a conventional photoelectric switch has a light receiving element 3 and a signal processing circuit 4 for processing a detection signal from the light receiving element 3 protruding from the surface of a flexible substrate 12. A backing material 13 is attached to the back surface of the flexible substrate 12 to provide strength.

[Problem that the invention attempts to solve]

The light receiving section 11 of the conventional photoelectric switch described above has the following problems. The backing material 13 attached to the back surface of the flexible substrate 12 needs to have a certain thickness in order to provide the flexible substrate 12 with a certain level of strength. If the thickness of this backing material 13 is too thin, the flexible substrate 12 may be deformed. Then, the light receiving element 3 and the signal processing circuit 4 on the flexible substrate 12 fall off from the flexible substrate 12 or are damaged. Alternatively, the angle of the light-receiving surface 3a of the light-receiving element 3 changes, making it impossible to perform a normal detection operation. Therefore, when trying to reduce the thickness of the light receiving section 11 of the photoelectric switch, it is impossible to reduce the thickness of the backing material 13 below a certain level, so there is a limit to how thin it can be.

There was also a problem in blocking the influence of noise on the light receiving section 11 of the photoelectric switch. The flexible substrate 12 can sufficiently block the influence of noise from below in the light receiving section 11 of the photoelectric switch (see FIG. 3). However, the influence of noise from above must be blocked by installing a new shielding material or the like. Therefore, when assembling the light receiving section 11 of the photoelectric switch, it is necessary to align the shield material and the light receiving element 3, etc., which is complicated. Furthermore, the number of parts increases due to the shielding material, and there are problems in that it takes time and effort to manage.

[Means for solving problems]

This idea was made in view of the above problem, and the specific means to solve this problem is to place the light receiving part built in the sensor body of the photoelectric switch on the outside of the board that can be folded in half. is coated with metal foil, a frame in which a light-receiving element is fitted is placed on one half-folded portion on the inner surface side of the substrate, and the substrate is folded in half on the other half-folded portion of the substrate. In some cases, a light-receiving window is provided at a position facing the light-receiving surface of the light-receiving element.

[Effect]

This idea took the above-mentioned measures, so
The influence of noise on the light-receiving part of the photoelectric switch can be sufficiently blocked, and the thickness of the light-receiving part of the photoelectric switch can be made thin without damaging the strength of the board on which the light-receiving element protrudes. .

〔Example〕

This invention will be explained in detail below based on examples. As shown in FIG. 1, the light receiving section 1 of the photoelectric switch according to this invention is formed by a flexible substrate 2 whose outer surface is coated with copper foil and can be folded into two. A light-receiving element 3 and a signal processing circuit 4 for processing a detection signal from the light-receiving element 3 are protruded from one half-folded portion on the inner surface of the flexible substrate 2. A frame 5 is fitted over the light receiving element 3 and the signal processing circuit 4. This frame 5
The thickness approximately corresponds to the thickness of either the light receiving element 3 or the signal processing circuit 4, whichever is thicker. Also,
The other half-folded part on the inner surface side of the flexible substrate 2 has a light-receiving surface 3a of the light-receiving element 3 when folded in half.
A light-receiving window 6 is bored so as to be located at a position opposite to the light-receiving window 6. In this embodiment, the frame body 5 is in the shape of a sun character, but it may also be in the shape of a mouth character.

Light receiving section 1 of the photoelectric switch according to this embodiment
There is a photoelectric switch shown in Fig. 2 that incorporates the following. This photoelectric switch 7
When the thickness is compared with the length in the vertical and horizontal directions,
It is relatively thin. Two screw holes 8 for mounting the photoelectric switch 7 are bored from the top surface to the bottom surface of the photoelectric switch 7. The upper surface also has a hole 9 at a position corresponding to the light receiving window 6.
is drilled. This hole 9 is for guiding the optical signal from the light emitting element to the light receiving section 1 of the photoelectric switch. Further, a seal 10 whose hole 9 is transparent is attached to the top surface. This sticker 10 usually has the same function as a so-called nameplate, on which the product name, product number, manufacturer's name, etc. are written. Therefore, by using this seal 10, dust, water droplets, etc. will not enter into the light receiving section 1 of the photoelectric switch through the hole 9.

[Effect of idea]

As is clear from the above explanation, this idea is
The outer surface of a substrate that can fold the light receiving section built into the sensor body of the photoelectric switch into two is coated with metal foil, and the frame body has a light receiving element fitted into one half-folded section on the inner surface of the substrate. The photoelectric switch The thickness of the light receiving section can be reduced. Furthermore, this substrate can sufficiently block noise from above and below the light receiving section of the photoelectric switch.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the first embodiment of this invention;
The figure is a perspective view of one embodiment of a photoelectric switch incorporating the light receiving section of the photoelectric switch according to this invention, and FIG. 3 is a perspective view of a conventional example. DESCRIPTION OF SYMBOLS 1... Light receiving part of a photoelectric switch, 2... Flexible board, 3... Light receiving element, 5... Frame.

Claims (1)

[Claims for Utility Model Registration] (1) A light-receiving section built into the sensor body of a photoelectric switch, the outer surface of which is a bifoldable substrate covered with metal foil, and one of the inner surfaces of the substrate. A frame body in which a light receiving element is fitted is placed on the half-folded part, and a frame for light reception is placed on the other half-folded part of the board at a position facing the light-receiving surface of the light-receiving element when the board is folded in half. The light receiving part of a photoelectric switch is characterized by a window. (2) The light receiving part of the photoelectric switch according to claim 1, wherein the substrate is a flexible substrate.