JPH0121440Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an optical fiber type photoelectric switch using an optical fiber.

Conventional fiber-optic photoelectric switches of this kind have been manufactured as unique models, which has led to an increase in the number of models, often causing problems in terms of inventory and delivery times.

By the way, amplifier-separated type photoelectric switches have been known for some time. As shown in FIGS. 1 and 2, this photoelectric switch separates an amplifier unit 1 containing all circuit sections from a sensor section 3 (consisting of a light emitting section 31 and a light receiving section 32). 3 has only a light emitting element 35 such as an LED and a light receiving element 36 such as a photodiode, and has lead wires 33, 34.
is connected to the screw terminal 21 of the socket 2, and the pin 11 of the amplifier unit 1 is inserted into the socket 2 to electrically connect the amplifier unit 1 and the sensor section 3.The sensor section 3 is a component. It has the advantage of being small in size due to the small number of parts, and that the amplifier unit 1 and sensor section 3 can be replaced with various types, and is useful in applications where the mounting space for the sensor section is small. Note that in FIGS. 1 and 2, the amplifier unit 1 houses an oscillation circuit 103, and its oscillation output pulses the light projecting element 35 to project pulsed light through the lens 37. , the light reflected by the detection object 4 is converged by a lens 38 and guided to a light receiving element 36. The light-receiving signal obtained from the light-receiving element 36 is guided to the detection circuit 106 through the AC amplification circuit 104 built in the amplifier unit 1 for detection, and the switching circuit 107 outputs a switching output depending on the presence or absence of reflected light. arise. and switching circuit 107
The output signal is sent to the relay drive circuit 109 via the operation changeover switch 108, and the output relay 110 is driven to generate a contact output. A light receiving circuit constituted by these circuits, a power transformer 101, and a stabilized power supply 102 are housed within the amplifier unit 1. The variable resistor 105 is used to adjust the degree of amplification of the AC amplifying circuit 104 to adjust the sensitivity, and its knob 12 is arranged on the panel of the amplifier unit 1. Further, a display 13 is placed on the panel to display the light incident state according to the operation of the switching circuit 107, and a knob 104 of an operation changeover switch 108 is also arranged.

Although this amplifier-separated photoelectric switch has various advantages as mentioned above, it requires the use of shielded cables that are expensive and difficult to work with as the lead wires 33 and 34, and the signals passing through these lead wires 33 and 34 are Since it is a weak and high frequency pulse signal, it also has the disadvantage of being susceptible to noise.

The present invention makes it possible to attach an optical fiber to the above-mentioned amplifier-separated type photoelectric switch via an adapter, thereby eliminating only the disadvantageous aspects of the amplifier-separated type. By attaching a fiber, you can configure an optical fiber type photoelectric switch by using the amplifier unit of a conventional amplifier-separated type photoelectric switch as is.
It is an object of the present invention to provide an optical fiber type photoelectric switch which solves the above-mentioned problems such as inventory management.

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 3 and 4, the light emitting optical fiber 51 and the light receiving optical fiber 5
One end of the optical fiber unit 5 consisting of
is also detachably attached to the screw terminal 21 of the socket 2. This adapter 6 performs electrical-to-optical conversion, and inside the adapter 6 is a light emitting element 61.
and a light receiving element 62 are built in, and one ends of optical fibers 51 and 52 are attached so as to face these elements, and the light from the light emitting element 61 is sent through the light emitting optical fiber 51, and from the other end to the lens. 5
3, the reflected light is guided to one end of the light-receiving optical fiber 52 via the lens 54, and this light is sent to the light-receiving element 62 through the light-receiving optical fiber 52. The other configurations of these Figures 3 and 4 are the same as those of Figures 1 and 2, in other words,
An optical fiber unit 5 is attached via an adapter 6 in place of the sensor section 3 in FIGS.

As shown in FIG. 5, the adapter 6 has a terminal portion 63 made of a printed circuit board, and this terminal portion 63 is adapted to be attached to the screw terminal 21 of the socket 2. A fixing base 64 for the optical fibers 51 and 52 is attached to this terminal portion 63 with screws 66. This fixing base 64 has a semi-cylindrical groove portion 64 for arranging the optical fibers 51 and 52.
a is provided, and the holding member 65 is also provided with a semi-cylindrical groove portion 65a. A light emitting element 61 and a light receiving element 6 are disposed on one end side of this groove 64a.
2 (these elements are electrically connected by being soldered to the conductive pattern of the terminal part 63) are arranged so that their central axes coincide with the cylinder formed by the combined grooves 64a and 65a. Ru. Then, the inner diameter of the semi-cylindrical grooves 64a, 65a is made slightly smaller than the outer diameter of the optical fibers 51, 52, and the holding member 65 is tightened with the tightening screw 67.
By attaching the optical fibers 51 and 52 to the fixing base 64, the optical fibers 51 and 52 can be crimped within the grooves 64a and 65a. As a result, the optical fibers 51 and 52 crimped in this manner are fixed with their ends facing the light emitting element 61 and the light receiving element 62 and with their central axes aligned. Furthermore, the lengths of the grooves 64a and 65a are the same as the lengths of the optical fibers 51 and 65a.
The diameter of the optical fiber is 10 to 20 times the radius of the optical fiber 52, and the optical fiber is fixed sufficiently firmly so that the compressive force in the radial direction (per unit length) of the optical fiber is relatively small. Transmission loss increases when the optical fiber is locally compressed in the radial direction, but since the above-mentioned method is used, no local force is applied and the increase in loss can be avoided.

When the optical fibers 51 and 52 are fixed by the fixing base 64 and the holding member 65 in this way, the ends of the optical fibers 51 and 52 are attached to the light emitting element 6, as shown in FIG.
1. They face each other at the center of the light receiving element 62, and efficient optical coupling can be achieved. Furthermore, since no special connector for optical fibers is used, the ends of the optical fibers 51 and 52 may be cut with a cutter or the like. This is because if optical fibers 51 and 52 are made of plastic, when cut with a sharp knife, the end portions will exhibit the same performance as optically polished fibers. In particular, in the case of bundle fibers made by bundling dozens of plastic fibers with a diameter of about 0.25 mm, sufficient characteristics can be obtained by cutting them with a new cutter. In this way, the ends of the optical fibers 51 and 52 need only be cut with a cutter or the like, so the length can be freely adjusted.

As described above with respect to the embodiments, the present invention allows most of the configurations of conventional amplifier-separated type photoelectric switches to be used in common, and moreover, the fiber unit and amplifier unit can be freely replaced. A fiber-type photoelectric switch can be realized.
Therefore, it is possible to solve the problems associated with an increase in the number of types of optical fiber type photoelectric switches that have conventionally been configured as specific models. Since the optical fiber is positioned and fixed by the semi-cylindrical groove provided in the fixing base and the holding member, it is possible to achieve good optical coupling between the light emitting element/light receiving element and the optical fiber with a simple mechanism and easy operation. can be achieved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional amplifier separation type photoelectric switch, FIG. 2 is a block diagram showing the circuit configuration of FIG. 1, FIG. 3 is a perspective view of an embodiment of the present invention, and FIG. 5 is an exploded perspective view of the adapter 6 shown in FIG. 3, and FIG. 6 is a sectional view of the adapter 6 shown in FIG. 1...Amplifier unit, 2...Socket, 3...
...Sensor section, 4...Detection object, 5...Optical fiber unit, 6...Adapter.

Claims (1)

[Scope of utility model registration request] It consists of an amplifier unit, a socket into which a pin of the amplifier unit is inserted, an optical fiber for emitting light, an optical fiber for receiving light, and an adapter that is detachably connected and fixed to the screw terminal of the socket, and this adapter includes: A fixing base having a semi-cylindrical groove formed therein; a presser member having the semi-cylindrical groove formed therein; a light emitting element and a light receiving element disposed on one end side of the groove of the fixing base at a position where the central axis coincides with the central axis of the cylinder formed by the cylindrical groove; An optical fiber type photoelectric switch which is fastened to the fixing base and each of the optical fibers is crimped and fixed within a cylinder formed by both semi-cylindrical grooves.