JP3926405B2 - Image fiber pixel alignment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pixel alignment method for satisfactorily aligning core fibers forming pixels of an image fiber in the manufacture of an image fiber.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, when manufacturing an image fiber, there is a process of aligning core fibers (optical fibers) forming pixels on a jacket tube called a stuffing process.
In the normal stuffing process, core fibers of the same diameter are arranged in as clean a shape as possible, bundled and fixed with tape, etc., and this core fiber alignment is inserted into a jacket tube with pure water etc. This is heated and drawn to obtain the target image fiber.
On the other hand, in order to randomize the pixel arrangement as another stuffing process, the core fiber primary wire drawing diameter is changed, and several kinds of core fibers having different core diameters are also bundled and fixed with tape or the like. Similarly, a method of obtaining an image fiber preform (different diameter core / image fiber preform) by being inserted into a jacket tube has been proposed.
[0003]
[Problems to be solved by the invention]
When core fibers of the same diameter are packed, some pixels are arranged in the six-method dense state (arranged in an ideal stacking state between the upper and lower pixels), but it is difficult to arrange them in a clean state as a whole. When viewed from the entire image fiber screen, there is a problem that they exist in a cluster. As a result, when the transmission image of the image fiber is observed on a monitor via a TV camera or the like, moire fringes may occur.
In addition, there is a problem that a portion where the core fiber is missing occurs due to disorder of the arrangement of the core fibers, and this becomes a black spot on the transmission image.
On the other hand, when fibers of different diameter cores are packed, the arrangement of the core fibers becomes random, and no moire fringes or the like occur, and a good image can be obtained, but as the length of the image fiber becomes longer, There is a problem that light and darkness occurs in each part of the pixel due to a difference in propagation constant between the pixels.
[0004]
The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a pixel alignment method of an image fiber in which core fibers forming pixels are arranged well.
[0005]
[Means for Solving the Problems]
According to the present invention, when aligning core fibers constituting pixels of an image fiber, a mold having a polygonal cross-sectional groove having at least one side opened in the longitudinal direction is prepared, and the opening of the one side is provided in the groove of the mold. From the polygonal core fiber alignment body, a part of the circular core fiber alignment body is extruded from the polygonal core fiber alignment body, and this is inserted into the jacket tube.
Alternatively, a polygonal core fiber alignment body is partially extruded from the mold, and the core fiber is replenished in an arc shape to the outer peripheral portion of the polygon of the core fiber alignment body so that the core fiber alignment body has a circular inscribed cross section. And aligning the image fiber into a jacket tube.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show one embodiment of a pixel alignment method of an image fiber according to the present invention.
First, in the present invention, as shown in FIG. 1, a mold (jig) 1 having a groove 2 having a polygonal cross section (for example, hexagonal) having at least one side opened in the longitudinal direction is prepared.
The length L of the longest portion of the groove 2 is preferably about 10% larger than the inner diameter of the jacket tube. The mold 1 may be made of metal. However, in order to avoid damage such as scratches on the surface of the core fiber, resin or a metal surface coated with resin is desirable. The length (full length) of the mold 1 is preferably longer (for example, about 50 mm) than the length of the core fiber.
[0007]
Next, partition plates (lids) 3 and 3 are set on both ends of the prepared mold 1 as described above, and this is submerged in pure water, for example.
In this state, as shown in FIG. 2, as the core fiber f, for example, silica glass optical fibers having the same diameter are dropped from the opening portion above the groove 2 several times (about one layer) and packed. At this time, in order to arrange the optical fibers, it is preferable to apply ultrasonic vibration to the pure water. Further, in order to suppress excessive movement of the optical fiber due to vibration, a fiber holding plate (lid) 4 may be placed on the opening of the mold 1.
By this packing, the core fibers f are arranged in a six-method dense state, which is an ideal arrangement state, over the entire surface. That is, an ideal stacking state is realized between the upper and lower core fibers f.
[0008]
In this way, when the core fiber f is filled in the groove, the mold 1 is taken out from the pure water, the partition plates 3 and 3 at both ends of the groove are removed, and as shown in FIG. A perforated partition plate 5 having a hole 5a substantially equal to the inner diameter of the jacket tube is set. On the other hand, an extrusion tool 6 having an extrusion portion 6a substantially equal to the inner diameter of the jacket tube is set in the other of the grooves 2 and extruded.
Then, as shown in the drawing, the core fiber alignment body F ₂ having a circular cross section is partially pushed out from the hole 5 a of the partition plate 5 from the polygonal (hexagonal) core fiber alignment body F ₁ in the groove 2. This extrusion length is, for example, about half of the total length of the mold.
Thereafter, a tape or the like is wound around the extruded portion and fixed, and the entire length is pulled out from the mold 1.
Next, the drawn core fiber alignment body F ₂ having a circular cross section is inserted into a jacket tube, such as a quartz glass tube, to obtain an image fiber preform.
[0009]
Incidentally, the core fiber f has a diameter of 270 μm, the dimension L of the mold 1 is 33 mm, the outer diameter is 33 mm, and the thickness is 1.65 mm. A fiber preform was obtained, and this was heated to about 1700 ° C. and drawn to obtain an image fiber having an outer diameter of 1.2 mm and a number of pixels of 1100, and this was coated with UV resin.
Since this image fiber has an ideal arrangement of pixels and is a six-method dense, an extremely good transmission image was obtained.
[0010]
4 to 5 show another embodiment of the image fiber pixel alignment method according to the present invention.
Also in this embodiment, the filling of the core fiber f into the groove 2 of the mold 1 is performed in the same manner as in the case of FIGS. 1 to 2, but after this filling, as shown in FIG. The partition plate 3 is removed and the other partition plate 3 is pressed to partially extrude the polygonal (hexagonal) core fiber alignment body F ₁ in the groove 2 from the mold 1.
[0011]
Next, by using a guide tube 7 which is inscribed in the polygonal core fiber aligning member F _1, the outer side portions of the polygonal core fiber aligning member F _1, with replenishing the core fiber f in an arc, The entire length is pulled out from the mold 1, and a tape or the like is wound around the outer periphery and fixed to form a core fiber alignment body F ₃ having a circular inscribed cross section.
Thereafter, the core fiber alignment body F ₃ having a circular inscribed cross section is inserted into a jacket tube, for example, a silica glass tube, to obtain an image fiber preform.
[0012]
Incidentally, the core fiber f having the same diameter is packed by using a jacket tube having a core fiber diameter of 270 μm, a dimension A of the mold 1 of 29.7 mm, an outer diameter of 33 mm, and a thickness of 1.65 mm. An image fiber base material was obtained and heated to about 1700 ° C. for drawing to obtain an image fiber having an outer diameter of 1.2 mm and a number of pixels of 1100, and this was coated with a UV resin.
Since this image fiber has a hexagonal dense arrangement of pixels at the center except for at least the outer periphery of the polygon that has been replenished with the core fiber f, an extremely good transmission image was obtained.
[0013]
The silica fiber based optical fiber of the core fiber f used in the present invention includes a pure silica core / fluorine doped quartz clad type, a pure quartz core / fluorine doped quartz clad / quartz jacket type, a germanium doped quartz core / fluorine doped quartz. Optical fiber such as clad type, germanium doped quartz core / fluorine doped quartz clad / quartz jacket type can be used, and pure silica glass and fluorine doped quartz glass tube can be used as the silica glass tube. Can be combined appropriately to form an image fiber.
In particular, in the case of a pure quartz core, one having excellent radiation resistance can be obtained. However, in the case where the dopant is mixed, since the softening temperature is lowered, it is necessary to make a combination that does not lose its shape.
[0014]
【The invention's effect】
As described above, according to the pixel alignment method of the image fiber according to the present invention, the core fiber can be aligned in a good shape by using a simple shape mold (jig). For example, when the groove of the mold is a polygon (such as a hexagon), the pixel arrangement at least in the center is in an ideal six-method dense state, so that a high-quality image fiber that realizes a good transmission image can be obtained.
Therefore, the occurrence of moire fringes can be minimized, and the occurrence of black spots due to the dropout of the core fiber can be effectively suppressed.
Further, when the core fibers are packed (aligned), the core fibers need only be dropped into the mold groove, the work is simple, no great skill is required, and good mass productivity is obtained.
Furthermore, since core fibers of the same diameter are used, there are problems such as light and dark in each pixel even when the length of the image fiber is long, as in the case where fibers of different diameter cores are packed. Absent.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a mold used in an image fiber pixel alignment method according to the present invention.
2 is a perspective view showing a state in which a core fiber is filled in a groove of the mold shown in FIG. 1; FIG.
FIG. 3 is a perspective view showing a state in which a circular core fiber alignment body is partially extruded from the groove of the mold of FIG. 1;
FIG. 4 is a perspective view showing a state in which a polygonal core fiber alignment body is partially extruded from the groove of the mold of FIG. 1;
5 is a perspective view showing a state in which core fibers are replenished in an arc shape on the outer side portion of the polygonal core fiber alignment body of FIG. 4; FIG.
[Explanation of symbols]
1 Type 2 Groove 3 Partition plate 4 Fiber holding plate 5 Perforated partition plate 6 Extruder 7 Guide tube F ₁ Polygon core fiber alignment body F ₂ Circular core fiber alignment body F ₃ Inscribed circular core fiber alignment body

Claims (3)

When aligning the core fibers that form the pixels of the image fiber, prepare a mold with a polygonal groove with one side open in the longitudinal direction, set partition plates at both ends of this groove, and use a liquid such as water. Sinking into the core, sequentially dropping the core fiber from the opening into the groove of the mold and stuffing, placing a fiber holding plate in the opening, giving ultrasonic vibration to the liquid to form a polygonal core fiber alignment body, Next, after removing the partition plates at both ends of the groove, a perforated partition plate having a hole substantially equal to the inner diameter of the jacket tube is set at one end thereof, and a pusher having an extrusion portion approximately equal to the inner diameter of the jacket tube is set at the other end. From the polygonal core fiber alignment body set with a tool, a core fiber alignment body having a circular cross section that is smaller than the core fiber alignment body and approximately equal to the inner diameter of the jacket tube Extrusion, this was fixed by winding a tape or, subsequently, pull the entire length of said core fiber alignment member, and thereafter, the pixel alignment method of image fiber, which comprises inserting into the jacket tube.   2. The pixel alignment method for an image fiber according to claim 1, wherein the mold is a resin or metal surface coated with a resin.   3. The image fiber pixel alignment method according to claim 1, wherein the groove of the mold has a hexagonal cross section and the opening has a size of one side of the hexagon.

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