JPS63253906A - Manufacture of optical fiber unit for photosensor - Google Patents

Abstract

PURPOSE:To decrease the working man-hour and to reduce the cost, by inserting a core exposed by peeling off a covered part of the tip part of an optical fiber, into a fitting tool forming metallic mold and bringing a fitting tool to synthetic resin forming, and also, bringing the core to insert forming to the fitting tool. CONSTITUTION:An exposed core 1A and its adjacent covered part 1A are inserted into a fitting tool forming metallic mold 8 and the metallic mold is closed, and thereafter, into this metallic mold 8, a synthetic resin is injected and formed. Thereafter, when the metallic mold 8 is opened, a fitting tool 9 having a screw groove on the outside peripheral surface is formed in a state that a core 1B has been brought to insert forming. In such a way, since the fitting tool 9 is formed as one body with the core 1B, a protective means by a covering of the resin is not required. Therefore, the working man-hour is curtailed and the manufacture can be executed at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of manufacturing an optical fiber unit mainly used in a fiber-type photoelectric switch or an optical sensor such as a color identification sensor.

<Prior art> Generally, in optical sensors such as fiber-type photoelectric switches that utilize optical fibers, the detection end and the light receiving element are connected with an optical fiber, but the optical fiber itself is made of a flexible material. It is difficult to position and fix the sensor at a predetermined detection position. Therefore, an optical fiber unit is used in which a fitting is fixed to the tip portion of the optical fiber, which is the detection end, for stably fixing the optical fiber to a mounting member. This optical fiber unit is manufactured through the steps shown in FIG. That is, as shown in Figure (a), the optical fiber 1 is first cut to the required length, and the coated portion 1A of the tip portion that will become the detection end is cut to the required length as shown in Figure (b). to expose core IB. As is well known, the core 1B is covered with a cladding, but in order to simplify the explanation, the cladding is not particularly illustrated in the following description and is simply referred to as the core 1B. Next, as shown in the same figure (C), after applying adhesive 2 made of resin to the exposed core 1B, this core 1B is shaped into a cylindrical shape having thread grooves on the circumferential surface, which has been previously manufactured by cutting or the like. At the same time, as shown in FIG. 3(d), the cap 3 is fixed to the core IB with adhesive 2. In this state, the core IB is protruding from the cap 3, so as shown in +8) in the same figure, after cutting and removing the protruding core IB to match the end surface of the cap 3, the cut surface of the core IB is Polish to avoid light scattering, etc. Furthermore, as shown in FIG. 3(f), the connecting portion between the cap 3 and the optical fiber 1 is filled with resin 4 to cover and protect it, and then the cap 3 is sealed as shown in FIG. The optical fiber unit is completed by screwing the two mounting nuts 5 and 6. When fixing this optical fiber unit 7) facing the detection direction, for example, as shown in the same figure (gl), the optical fiber unit is completed. The member 7 is clamped and fixed with a pair of mounting nuts 5.6.

<Problems to be Solved by the Invention> However, the manufacturing method described above requires a large number of processing steps, and moreover, requires relatively complicated operations such as applying the adhesive 2, inserting the cap 3, and covering with the resin 4. In many cases, this is a factor in the high cost.

Furthermore, since the cap 3 is generally made of metal, the material and processing costs are high, which also increases the cost.

Further, since the cap 5.6 is fixed to the core 1B by the insertion means, the shape of the cap 5.6 is naturally limited and the degree of freedom is narrow. Furthermore, since the core 1B and the fixture 3 are fixed together using the adhesive 2, there are variations in bonding strength due to differences in the amount of the adhesive 2, etc.

<Objective of the Invention> The present invention has been made in consideration of the problems of the conventional manufacturing method, and it can be manufactured at a low cost by reducing the number of processing steps, and has a wide degree of freedom in the shape of the tip fitting. Moreover, it is an object of the present invention to provide a method for manufacturing an optical fiber unit for a photosensor, which allows a fixture and an optical fiber to be firmly fixed without variation.

Means for Solving the Problems〉 The method for manufacturing an optical fiber unit for a photosensor of the present invention includes the following steps:
In order to achieve the above object, there is provided a method for manufacturing an optical fiber unit for a photosensor, which comprises fixing a fitting to the tip of an optical fiber to fix it to a mounting member, the method comprising coating the tip of the optical fiber. The core is peeled off to a required length to expose the core covered with kraft, and this core is inserted into a mold for molding the fixture to mold a fixture from synthetic resin, and the core is inserted into the fixture. The core is insert-molded, and then the core protruding from the fixture is cut to a predetermined length or to match the end face of the fixture.

Since the auxiliary attachment is integrally attached to the optical fiber core by molding synthetic resin, the conventional manufacturing methods of applying adhesive to the core, inserting the core into the base, and coating with resin are all complicated. This eliminates the need for additional work and reduces machining man-hours. In addition, by forming the fixture using synthetic resin molding, the degree of freedom in the shape of the fixture is greatly increased, and
Since the core is insert-molded into this fixture, the connection between the two is stable and strong, and the cost can be further reduced by using an inexpensive synthetic resin as the material for the fixture.

<Example> Hereinafter, preferred examples of the present invention will be described in detail with reference to the drawings.

In FIG. 1 showing the manufacturing process of one embodiment of the present invention,
The machining shown in Figures (a) and fb) is shown in Figures 3 (a) and (b).
Since it is exactly the same as , the explanation will be omitted. Figure 1 (C1
In this step, the exposed core 1A and the covering portion 1A in the vicinity thereof are inserted into the fixture molding mold 8 and the mold 8 is clamped, and then a synthetic resin is injected into the mold 8. Shape. After that, when the mold 8 is opened, a fitting 9 having a thread groove on the outer circumferential surface is formed by insert molding the core IB, as shown in FIG.
Since the core IB is molded integrally with the core IB, there is no need for any protective means such as the resin coating shown in FIG. 3(f). Then, as shown in FIG. 1(e), the core IB protruding from the fixture 3 is cut and removed so as to match the end face of the fixture 9, and this cut surface is polished, as shown in FIG. 1(f). By screwing a pair of fixing naphes 5 and 6 onto the fixture 9,
The optical fiber unit for optical sensors is completed.

From now on, the method for manufacturing the optical fiber unit for sensors will be described in the first step.
In the machining process shown in Figure (C), the fixture 9 is attached to the core 1B.
Since it is formed of synthetic resin in an insert-molded state, conventional manufacturing methods do not require applying adhesive to the core IB, inserting the core into the base, and covering the joint between the fitting and the optical fiber with resin. All of these processes are no longer necessary, reducing the number of processing steps and reducing costs.

Furthermore, since the fixture 9 is made of an inexpensive synthetic resin material, it is even cheaper. Furthermore, since the core IB is integrally formed with the fixture 9 by insert molding, the connection between the two is extremely strong, and there is almost no variation in the bond strength. Furthermore, the fixture 9 formed by molding of synthetic resin can be obtained in various shapes by changing the shape of the mold 8.

Further, in photoelectric switches and the like, the detection end is often provided in a narrow space by utilizing the characteristics of the optical fiber 1 that it is thin and easily bent. In this case, since the optical fiber 1 itself is flexible and difficult to position and fix at a predetermined detection position, as shown in FIG. The tip sleeve portion 1 is inserted through the sleeve portion 10 made of stainless steel or the like.
0, for example, by avoiding the illustrated obstacle 11 and detecting end 10.
' is bent so as to be located at a predetermined detection position, and the rear end of this sleeve part 10 is fixed to the fixture 9. When manufacturing such an optical fiber unit, in the process shown in FIG.
A is exposed, and in the process shown in FIG. The core 1B protruding from the tip is inserted into the sleeve part 1.
What is necessary is to perform a step of cutting and removing the material so as to match the end face of 0 and polishing the cut surface.

The manufacturing method of the present invention can be applied to plastic fibers as well as glass fibers, and if the fixture 9 is molded using double molding technology, this can be done without affecting the material of the plastic core. The fixture 9 can be resin molded around the . Further, in the case of a plastic fiber, it is preferable to polish the cut surface by heating the cut surface to a molten state and then pressing the cut surface to a mirror surface.

<Effects of the Invention> As detailed above, according to the method of manufacturing an optical fiber unit for a photosensor of the present invention, the core exposed by peeling off the coating at the tip of the optical fiber is placed in a mold for molding a fixture. By using the process of inserting and molding the fixture with synthetic resin and insert molding the core into the fixture, it is possible to apply adhesive to the core, insert the core into the fixture, and connect the fixture and optical fiber. All processes that require complicated work such as coating the connection parts with resin are no longer necessary, reducing the number of processing steps, and by forming the fittings from inexpensive synthetic resin, significant cost reductions are achieved. be able to. Further, by molding the fixture with resin, the degree of freedom in its shape is greatly increased, and for example, in addition to a threaded shape having a thread groove on the outer circumferential surface, it can be made into various shapes with non-circular cross-sectional shapes. Furthermore, the core and the fixture are firmly connected without variation by resin molding.

[Brief explanation of the drawing]

FIGS. 1(a) to (fl) are diagrams showing the manufacturing process of one embodiment of the method for manufacturing an optical fiber unit for photosensors of the present invention, and FIG. 2 is an optical fiber unit manufactured according to another embodiment of the present invention. 3(a) to (a) are diagrams showing the manufacturing process of the conventional manufacturing method. 1...One optical fiber...Coating part 1B...Core (cladding) 8...Molding mold 9...Fixing tool (c) (d) Figure 2 100 (C) (d) ((2)

Claims (2)

[Claims] (1) A method for manufacturing an optical fiber unit for a photosensor, which comprises fixing a fitting to the tip of an optical fiber to fix it to a mounting member, the method comprising: cutting the coating at the tip of the optical fiber to a required length; peeling off the cladding to expose the core covered with the cladding, inserting this core into a mold for molding the fixture to mold the fixture from a synthetic resin, and insert-molding the core into the fixture, A method for manufacturing an optical fiber unit for a photosensor, comprising the step of cutting the core protruding from the fixture to a predetermined length or to match the end face of the fixture. (2) The method for manufacturing an optical fiber unit for a photosensor according to claim 1, characterized in that after cutting the core protruding from the fixture, the cut surface is polished.