JPS63155008A - Production of optical fiber sheet - Google Patents

Abstract

PURPOSE:To uniformize the light transmissivity by using a converging guide to bring plural stages of fibers spun out from spinning nozzles and fusion-fixing them to converge them into one sheet. CONSTITUTION:Plural stages of optical fibers 3 spun out from a spinning nozzle 1 where discharge ports 2 are zigzag arranged in plural stages on a plane and respective stages of all discharge ports 2 do not overlap on a side face are brought into contact with one another and are fusion-fixed to each other with a converging guide 5 and are converged into one optical fiber sheet 4. With respect to the converging guide 5, a cooled narrow bar-shaped body is worked into an arc and has the surface subjected to the surface smoothing work such as specular working, chromium plating, 'Teflon(R)' impregnation working, or the like. Thus, the light transmissivity is uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing an optical fiber sheet used for various image guides, sensor heads, or displays.

(Prior Art) Optical fiber sheets have conventionally been used as elements for various image guides and sensor heads, or for displays, and the range of applications is expanding more and more.

Various methods for manufacturing optical fiber sheets have been proposed. As one such method, Japanese Patent Application Laid-open No. 49-84452 and No. 49-90151 describe a method of winding and fixing optical fibers in a line around a drum. However, this method has the problem that although the width is variable, the sheet length is limited and the productivity is poor.

As a method for continuously manufacturing sheets, there is
46340 or the method proposed in Japanese Patent Application Laid-Open No. 58-68006, in which a large number of optical fibers are guided from a yarn feeding creel, warped and bonded using a number of guides such as reeds, and made into seams. be.

The problem with this method is that it uses a large number of guides, which can cause damage to each other, and that it is very difficult to maintain constant tension between each optical fiber, which can easily lead to product defects. This method requires the use of adhesives, which poses problems such as complicated work and high costs.

On the other hand, as an efficient method of continuously forming sheets, Japanese Patent Publication No. 42-27585 or Japanese Patent Application Laid-Open No. 50-8540 proposes a method of fusion bonding during the fiber or optical fiber spinning process. These methods fuse uncooled fibers discharged from a large number of discharge holes, do not use adhesives, are extremely simple in terms of workability, and are advantageous in terms of cost. The problem with this method is that the number of fibers is limited by the number of holes in the base, and the light transmittance of the optical fiber may deteriorate due to the arrangement of the ejection holes and the focusing method, as shown in the example of the above patent. In a simple linear arrangement, as the number of ejection holes increases, the contact between the ends of the fibers and the width regulating guide for focusing becomes tighter, or the contact angle between the fibers becomes tighter, which tends to cause deterioration of the light transmittance. There was a problem that a suitable optical fiber sheet could not be obtained. In order to solve these problems, Japanese Patent Application Laid-open No. 60-1'l 7202 proposes a method of using a circular discharge hole array and converging with an arcuate guide. This method has the advantage that the number of holes is increased and the angle of the fibers to be focused does not increase that much even if the number of holes is increased, making it difficult to cause deterioration of light transmission, but since the fibers are focused inside the circular guide, the bonding start point It is difficult to observe, the work is complicated, and defects are likely to occur.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problems of the particularly efficient direct spinning method among the various sheet-forming methods mentioned above, and to achieve uniform translucency from a large number of optical fibers. The purpose of this invention is to provide a method for efficiently manufacturing optical fiber sheets.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object. That is, (1) a multi-stage product spun from a spinneret in which the discharge holes are arranged in a staggered manner in a plurality of stages in a plan view, and in which all rows of discharge holes are arranged without overlapping in a side view; 1. A method for producing an optical fiber sheet, which comprises converging the fibers into a single sheet by contacting and fusing the fibers using a convergence guide.

(2) The focusing guide moves the cooled thin rod-shaped body into an arc of 1'
Claim No. (
&la method of optical fiber sheet as described in section 1).

(3) Focusing guide is mirror-finished, chrome-plated, and Teflon.
The method for producing an optical fiber sheet according to claim 1, wherein the optical fiber sheet is subjected to some kind of surface smoothing process such as impregnation process.

The present invention will be explained below with reference to figures of examples. FIG. 1 shows an example of the arrangement of the discharge holes of the mouthpiece of the present invention. 1 is a mouthpiece, 2 is a discharge hole, and in the case of (a), the discharge holes are arranged in a staggered manner in three rows, and the projected arrangement interval of all discharge holes when viewed from the direction perpendicular to this row is Q1. Q2. It is important that U3°... be the same. By arranging in multiple rows in this manner, the number of ejection holes can be easily increased, and it is also possible to easily collect the ejection holes to form sheets.

Figure 1 (b) shows a case of a modified staggered arrangement in which the number of holes in each row is different and there is no regulation at both ends of the row, but when the number of rows increases, such random row ends Otherwise, the cap would have to be large in order to accommodate the required number of holes, resulting in wasted parts of the cap. Also, the projection array interval α1.
Q2. Q3. If . As an example, when 1 q of sheets with a fiber diameter of 250 μ are desired, the projected ejection hole interval may be set to 250 μ, and the ejection hole interval within one row is set to 2 mm, and this can be achieved by arranging the ejection holes in 8 rows. Furthermore, in the case of a 100μ fiber, in order to set the projected discharge hole interval to 100μ, the discharge hole interval should be set to 1.5 mm.
This is possible by arranging the discharge holes in 15 rows. Although the number of holes in one row is determined by determining the sheet width, the method of the present invention allows a large number of discharge holes to be arranged in a very small space. FIG. 2 is a diagram showing the positional relationship between the fiber in a spun state and the guide, and FIG. 2 (A) is a view seen almost from the front, and FIG.

In FIG. 2, 3 is a fiber, 4 is a sheet formed by forming each fiber into a sheet, and 5 is a focusing guide for forming the sheet.

In this case, since the fiber diameter and the projection hole interval are made equal, a width-aligning guide is not necessary, but if the projection hole interval is larger than the fiber diameter, it is preferable to use a bar-shaped arcuate guide. The drum guides can result in differences in bond strength between the fibers of the sheet due to the varying contact distance of each fiber to the guide. 6, after drawing and rowing, the fiber sheet is stretched by non-contact heating to impart strength and flexibility. FIG. 3 shows a focusing guide, with reference numeral 7 indicating an introduction section for guide cooling water, and numeral 8 indicating a discharge section. This is to cool the focusing guide 5, but if it is not actively cooled, the focusing guide will become hot due to contact with the high temperature fiber that has not yet been cooled, and will fuse with the fiber, resulting in stable spinning. This resulted in the problem that the fiber could not be used, and that the fiber was deformed. The focusing guide 5 is not drum-shaped, but thin, i.e. 4~
It is a rod-shaped object with a diameter of 1Q mmφ that is processed into a circular arc. It has been found that when the fibers are shaped like an hourglass with curvature, the fibers come into contact with the cooled guide before adhering to each other, and are cooled and do not fuse. Therefore, it has been found that a circular arc guide with a constant diameter is extremely effective in allowing the fibers to come into contact with each other and fuse together when they are focused on the guide. By cooling the guide, the fiber is cooled and solidified the moment it comes into contact with the guide, so it is possible to prevent the fiber from being damaged or deformed by contact with the guide. On the other hand, since the fiber is brought into contact with the focusing guide at a considerable angle, no matter how cool it is, if the guide surface is rough or rough, the fiber will be damaged. Therefore, the guide surface must be finished as smooth as current technology allows. Examples include electrolytic polishing, mirror finishing such as puff processing, hard chrome plating, and "Teflon" impregnation treatments.

The optical fiber used in the present invention is not particularly limited as long as it is a polymer that can be melt-spun, but the core component may be polycarbonate or polystyrene.

An optical fiber made of polymethyl methacrylate or a copolymer thereof, and the sheath component is polymethyl methacrylate, fluorine-containing methacrylate, vinylidene fluoride copolymer, or the like.

(Example) Example 1 A nozzle of the type shown in FIG.
The diameter was 48 mm, the hole diameter was 0.43 mm, the number of two rows was 4°, and the total number of discharge holes was 80. The core component is polymedyl medacrylate,
Vinylidene fluoride cladding material was used for the sheath component. Second
According to the method shown in the figure, it is picked up at 22.7 m/m r n.
Next, the film was stretched 2.2 times using a hot air circulation heater set at 150'C and wound up at 50 m/min.

A chromium-plated hollow pipe with a shaft diameter of 1 ctn was used as the focusing guide, and cold water at 20'C was passed inside the shaft to cool the focusing guide. Focusing guide position is below the cap, 20c
It was set as m.

The resulting sheet was a fiber sheet with a single yarn diameter of 250 μm and a width of 2 cm+-30 μm from sheet 1, with no deformation in the single yarns, and was a homogeneous sheet with no unevenness or bending in appearance.

The light transmittance of this fiber sheet was 250 dB/Km at a wavelength of 650 nm.

Example 2 A nozzle of the type shown in FIG. 1(A) was used, the discharge hole interval in the row was 1 mm, the hole diameter was 0.16 mmφ, the number of inner holes in the row was 60, the number of rows was 10, and the projected hole interval was 0. The total number of ejection holes with a diameter of 1 mm is 600. The row spacing was also 1 mm. Using this spinneret, spinning was carried out in the manner shown in Figure 3.

The core material was polymethyl methacrylate, and the sheath material was vinylidene fluoride. The focusing guide was a large round guide with a radius of curvature of 1 Qcm. Pick-up speed '250m/min
, followed by stretching twice at a temperature of 140'C to 100
It was wound up at m/min.

The focusing force id was cooled by passing water at 25°C, and the guide position was 5 cm below the mouthpiece. In addition, the surface 98 of the kite was immediately impregnated with Teflon.The obtained fiber was a highly homogeneous fiber sheet with a single fiber diameter of 50 μm and a sheet width of 3 cm+-20 μ.This fiber sheet The light transmittance was 980 dB/Kmri under white light.

(Effects of the Invention) The present invention can efficiently produce a homogeneous optical fiber sheet with good workability even with a very large number of fibers.

[Brief explanation of the drawing]

FIG. 1 shows an example of the discharge hole arrangement of the mouthpiece used in the present invention. In FIG. 1, (a) is a staggered arrangement (b) is a modified staggered arrangement, which shows the difference in regularity. FIG. 2 shows the positional relationship between the fiber and the guide in an actual spinning state. In Figure 2, (a) is the front (or back) view, (
B) is a side view. Figure 3 shows one of the focusing guides in Figure 2.
The example shows the use of arc guides. 1: Base, 2: Discharge hole, 3: Optical fiber, 4: Sheet optical fiber, 5: Focusing guide, 6: Taking-off roller, 7:
Cooling water introduction part, 8: Cooling water discharge part. 9: Auxiliary guide.

Claims (3)

[Claims] (1) A multi-stage yarn spun from a spinneret in which the discharge holes are arranged in a staggered manner in two or more stages, and each row of discharge holes is arranged without overlapping in the side. 1. A method for producing an optical fiber sheet, which comprises the step of converging the fibers into one sheet by contacting and fusing the fibers using a convergence guide. (2) The method for manufacturing an optical fiber sheet according to claim (1), wherein the focusing guide is an arc-shaped focusing guide obtained by processing a cooled thin rod-shaped body into a circular arc. (3) The method for manufacturing an optical fiber sheet according to claim (1), wherein the focusing guide is subjected to some kind of surface smoothing process such as mirror finishing, chrome plating, Teflon impregnation process, etc.