JPH03243903A - Production of image fiber - Google Patents

Abstract

PURPOSE:To obtain the image fiber which has the small diameter necessary for a medical treatment, etc., and has good flexibility by rotating an image fiber base material by a prescribed angle at every prescribed time interval. CONSTITUTION:The image fiber base material 10 is drawn to the image fiber 20 of 500mum outside diameter at 0.7mm/min feed speed and 1m/min take-off speed of the fiber. The image fiber base material 10 is rotated once at every one minute interval. The drawn image fiber 20 is, therefore, provided with about 8cm twists 32 at 1m intervals. This image fiber 20 has 0.5 contrast at 1m including the twist 32. The contrast is 0.3 contrast likewise at 1m when the base material 10 is not rotated. Improvement in characteristics is thus made. After the twists 32 are applied to the image fiber 20, the fiber is solidified and is subjected to primary coating. The improved flexibility is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing an image fiber used particularly in short lengths.

[Prior Art] FIG. 2a is a general explanatory diagram of a method for manufacturing an image fiber.

Reference numeral 10 denotes an image fiber base material, which is made up of a quartz tube 12 and a large number of pixel lines 14 arranged and packed in it, as shown in FIG. 2b.

This image fiber base material 10 is heated 78 in a heating furnace 16 and drawn, and immediately after solidification, a coating device 18
The image fiber 20 is provided with a primary coating.

40 is a caterpillar for take-up, and 42 is a winding bobbin.

Conventionally, image fibers are often used for industrial purposes, and the length is also very long! Long ones longer than am were used.

However, recently, they have come to be used for medical purposes, and short ones with a length of 1 m or less (in some cases, 1 Oci or less) have also been used.

When such a short length is used, there is a problem in that unnecessary light incident on the light beam is propagated as is without being attenuated, which may adversely affect the transmitted image. In other words, problems arise such as reduction in contrast and deterioration in resolution.

Note that unnecessary light refers to the core 2 of the image fiber 20.
2 (Figure 3, light 2 incident at an angle greater than or equal to the critical angle 08)
6 and the light 28 incident on the cladding 24, which are distinguished from the propagating light 30.

Conventionally, image fibers have been bent to remove unnecessary light.

However, this method not only takes up a lot of space, but also
It was not suitable for extremely short image fibers.

Therefore, it has been proposed to give the manufactured image fiber 20 a twist 32, as shown in FIG.

[Problem to be Solved by the Invention] To give the twist 32, a part of the image fiber 20 is heated and then subjected to a printing process.

However, in the section processed in this way, the coating layer is damaged by the heat during heating and becomes mechanically weak, so it is necessary to provide reinforcement 34 as shown in FIG. 4b.

As a result, it becomes thick and has poor flexibility, making it unsuitable for applications that require a small diameter and flexibility, such as medical applications.

[Means for Solving the Problem] As shown in FIG. 1a, when drawing the image fiber preform 10, the image fiber preform 10 is rotated by a predetermined angle at predetermined time intervals.

[Function] When the image fiber preform 10 is drawn to become the image fiber 20, the temperature decreases and solidifies.

When the image fiber base material 10 is rotated, the unsolidified portion above the solidified portion of the image fiber 20::
, a twist 32 occurs.

As the image fiber 20 solidifies, the twist 3
2 is fixed (does not lose its shape), and immediately after that, the coating device 1
A primary coating is applied at 8.

[Explanation of old manufacturing notes] (Figures 1a to 1C) This is almost the same as the conventional case shown in Figure 2a, but a motor 46 is connected to the chuck 44 of the image fiber base material 10, and the image fiber base material 10 is The material 10 can be given intermittent rotation.

Although not particularly shown, the image fiber base material 1
0 can be sent downward.

The image fiber preform 10 is fed downward at a constant speed and rotated at predetermined time intervals while being drawn to provide an image fiber 201:tt 32.

The image fiber 20, which has been given a twist 32, is solidified and coated as described above.

As described above, since the image fiber 20 is solidified properly when subjected to the twist 32 and is coated with the primary coating, there is no possibility that the portion of the twist 32 becomes mechanically weak.
No particular reinforcement is required.

The rotation angle is typically less than 360''.

Since the twist 32 only needs to be twisted at 11 points in the length of the image fiber 20 used, the time interval for giving rotation to the image fiber 20 is
0 and the feeding speed of the image fiber preform 10.

As described above, an image fiber 20 with twists 32 at predetermined intervals is obtained (Figure 1B), and it is cut to a required length to obtain an image fiber 20 with twists 32 (Figure 1C). ).

[Example] As the image fiber base material 10, 6000 pixel lines 14 each having an outer diameter of 200 μm were arranged and packed into a quartz tube 12 having an outer diameter of 20 g+m and an inner diameter of 18 mm.
I prepared one for pixels.

Feeding speed of image fiber base material 10: 0.7u+/min,
An image fiber 20 having an outer diameter of 500 μm was drawn at a fiber drawing speed of 1++/min.

At that time, the image fiber preform 10 was rotated once every minute. The time required for one rotation was about 5 seconds. By doing so, twists 32 of approximately 8 cm were applied to the drawn image fiber 20 at intervals of 1a+.

When this image fiber 20 was measured at 1 m including the twist 32, the contrast was 0.5.

On the other hand, when the image fiber base material 10 was not rotated, the contrast was the same (0.3 at 1 m), demonstrating that the characteristics were improved.

[Effect of the invention] When manufacturing an image fiber by drawing an image fiber base material and applying a primary coating to the solidified trench, the base material is rotated by a predetermined angle at predetermined time intervals. By doing this, you will get the following effect:

(1) As mentioned above, the twist 32 is
Since it is fixed as it hardens and the primary coating is applied immediately thereafter, there is no need for any particular reinforcement.

(2) Therefore, it is possible to obtain an image fiber with a small diameter and good flexibility, which is necessary especially for medical applications.

[Brief explanation of drawings]

Figures 1a to 1C are explanatory diagrams showing the actual 1M example of the manufacturing method of the present invention in the order of steps, Figure 2a is an explanatory diagram of the conventional image fiber manufacturing method, and Figure 2b is the same as that of Figure 2a. An enlarged cross-sectional view of B-B, FIG. 3 is an explanatory diagram of unnecessary light, and FIGS. 4a and 4b are explanatory diagrams showing the conventional method of giving twist 32. 10: 12: 14: 16 : 18: 20: 2- 34: 44: 46= Image fiber base material quartz tube pixel element wire heating furnace coating device image fiber twisting prosthesis chuck motor

Claims (1)

[Claims] An image fiber manufacturing method in which an image fiber preform is drawn and a primary coating is applied immediately after solidification, comprising: rotating the preform by a predetermined angle at predetermined time intervals. , a method for manufacturing an image fiber.