JPH1184147A - Optical fiber and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable light leakage without the unequalness of a light quantity over the entire part of the longitudinal direction of an optical fiber of a sea-and- island structure arrayed with plural pieces of light transmittable island parts in a sea part by arraying the light transmittable island parts in a helix state at a helix angle of a prescribed angle or above in the longitudinal direction of the optical fiber described above. SOLUTION: The optical fiber of the sea-and-island parts arrayed with plural pieces of the light transmittable island parts in the sea part is arrayed with the light transmittable island parts in the longitudinal direction of the optical fiber in a helix state at the helix angle of the prescribed angle or above in the longitudinal direction of the optical fiber. The helix angle for each 1m of the optical fiber is preferably specified to >=60 deg.. The island parts of the optical fiber of the sea-and-island parts are the parts corresponding to the core part or core/sheath part of the single optical fiber. The material constituting the core part is exemplified by polymethyl methacrylate, etc., of quartz, etc. The material constituting the sheath part is exemplified by poly-vinylidene fluoride, etc., and the material constituting the sea part is exemplified by polymethyl methacrylate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber and an illuminating device having excellent lateral light leakage characteristics suitable for lighting applications and the like.

[0002]

2. Description of the Related Art An optical fiber having a sea-island structure is used for image transmission (JP-A-2-176605, JP-A-4-166680).
No. 6) and those for sensors (JP-A-9-15432 and JP-A-5-40180) are known. However, in these optical fibers, the light transmitting islands have a structure arranged in parallel in the longitudinal direction of the optical fiber.

[0003] An illuminator that allows light to enter from an end of an optical fiber bundle and leak light from the side surface of the optical fiber is used as an illuminator in a pool or the like. Such an illuminating body usually has a structure in which optical fibers bundled in a spiral shape are housed in a tube made of a transparent vinyl chloride resin in order to improve light leakage and make the amount of light leakage uniform.

[0004]

However, since it is practically impossible to uniformly bundle the optical fibers in a helical shape over the entire longitudinal direction, the amount of light emitted from the side surface of the optical fiber is small in the longitudinal direction. The problem is that spots are formed over the entire area. Another problem is that a large amount of light leaks from the sheath portion of the optical fiber damaged by rubbing of the fibers during storage operation in a tube or the like, and that portion becomes a bright spot.

An object of the present invention is to provide an optical fiber capable of leaking light from the side surface of the optical fiber over the entire length of the optical fiber without unevenness.

[0006]

An object of the present invention is to provide an optical fiber having a sea-island structure in which a plurality of light-transmitting islands are arranged in a sea, wherein the light-transmitting islands are arranged in a predetermined length in the longitudinal direction of the optical fiber. The problem is solved by an optical fiber that is arranged in a twisted state with a twist angle greater than the angle.

[0007] The above-mentioned object is achieved by a lighting device including an illuminator in which one or more optical fibers are housed in a transparent tube, and a light source disposed at at least one end of the illuminator.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An island in an optical fiber having a sea-island structure is a portion corresponding to the core or core / sheath of a single optical fiber. When the island is composed only of the core, the sea is the sheath.

Examples of the material constituting the core include known organic materials such as polymethyl methacrylate, polycarbonate and polystyrene, and known inorganic materials such as quartz. Examples of the material constituting the sheath include known materials such as polyvinylidene fluoride and fluoroalkyl methacrylate / methyl methacrylate copolymer. Examples of the material constituting the sea part include known materials such as polymethyl methacrylate, polycarbonate, and vinylidene fluoride / tetrafluoroethylene copolymer.

The outer shape of the sea-island structure optical fiber is not particularly limited, but is usually circular. The outer diameter is not particularly limited, but is, for example, about 1 to 20 mm. The larger the outer diameter of the optical fiber, the lower the flexibility of the optical fiber and the more difficult it becomes to bend. So in that case,
When a material having a lower flexural modulus than the island member is used as the sea member, the flexural modulus of the optical fiber is reduced and the flexibility can be improved.

When the island has a core-sheath structure and a material that can function as an optical fiber is used as the material of the core and the sheath, a material having a higher refractive index than the island can be used as the material of the sea. Yes, this widens the choice of marine materials.

For example, as a core material, polymethyl methacrylate (refractive index: 1.49), and as a sheath material, a vinylidene fluoride / tetrafluoroethylene copolymer (refractive index: 1.40)
When 2) is used, as a sea material, polyretylene (refractive index: about 1.51 to 1.54) or vinyl chloride (refractive index: 1.50)
１．５1.55) can be used.

In order to emit light leaked from the inside of the optical fiber from the side without being absorbed by the sheath and the sea, it is particularly preferable to select a material having excellent transparency for both the sea and the sheath.

The typical shape of the core or island is circular or hexagonal. In the case of a circular shape, the diameter is not particularly limited, but is, for example, about 20 to 1000 μm. The number of islands is not particularly limited, but is, for example, about 5 to 200.

As a method of preventing damage to the optical transmission portion at the outer periphery due to rubbing of the fibers during processing, it is preferable to provide a protective layer on the outer periphery of the optical fiber having the sea-island structure. As the material of the protective layer, it is preferable to use a material having a relatively low glass transition temperature and excellent mechanical strength, and examples thereof include polyvinylidene fluoride and a vinylidene fluoride / tetrafluoroethylene copolymer.

The twist angle per meter of the optical fiber is not particularly limited, but is preferably 60 degrees or more.
It is more preferably 0 ° or more, and particularly preferably 360 ° or more.

It should be noted that the twist angle is determined by the island portion A existing at the outermost periphery at one end of the optical fiber cut to a predetermined length.
And two radii R connecting the center of the optical fiber cross section at both ends and the center of the island A.
It is represented by the angle difference between 1 and R2. Therefore, the island at the center of the optical fiber does not necessarily need to be in a twisted state.

As the transparent tube constituting the illuminator, a tube made of a known resin such as vinyl chloride or polyethylene can be used. A known light source can be used.

[0019]

The present invention will be described in detail with reference to the following examples. In the examples, "parts" means parts by weight.

Example 1 A composite spinning nozzle of φ2
In a cross section of 0 mm, a two-layer structure nozzle having an inner layer (pore diameter: 1.0 mm) / outer layer (flapper shape diverging from a hole diameter of 1.1 mm to a hole diameter of 2.3 mm) is evenly arranged in a staggered manner. In the lower part of the outer layer nozzle hole, the inlet diameter φ20
mm and a structure having a funnel-shaped throttle portion with a discharge hole diameter of φ4 mm were used.

Polymethyl methacrylate was used as the material for the core, and a copolymer of vinylidene fluoride / tetrafluoroethylene = 72/28 (parts) was used as the material for the sea. These resins were supplied to a melt extruder set at a temperature of 220 ° C., and the material for the core was introduced into the inner nozzle, and the material for the sea was introduced into the outer nozzle.

At the lower part of the outer layer nozzle, the marine material discharged from each outer layer was melted and discharged from the composite spinning nozzle, and wound while being twisted. In this manner, an optical fiber having a sea-island structure in which the island portion was composed of only the core portion and the number of the island portions was 37 was obtained.

The outer shape of the obtained sea-island structure optical fiber is 1
000 μm, and the diameter of each island was about 140 μm. The twist angle of the light transmitting island per meter in the longitudinal direction of the optical fiber was 360 degrees.

The 60 optical fibers were bundled in parallel and housed in a transparent vinyl chloride resin tube having an outer diameter of 12 mm, an inner diameter of 10 mm, and a length of 20 m. Light sources were arranged at both end surfaces of the optical fiber bundle, and light was leaked from the side surface of the tube.

Example 2 A composite spinning nozzle of φ2
Within a cross section of 0 mm, 37 three-layer nozzles with three layers of inner layer (pore diameter: 1.0 mm) / intermediate layer (pore diameter: 1.1 mm) / outer layer (flared from 1.2 mm to 2.3 mm in diameter) are staggered. The diameter of the inlet is φ20 mm and the diameter of the discharge hole is φ4 mm below the outer layer nozzle hole.
Of a structure having a funnel-shaped narrowed portion was used.

As the material for the sheath of the intermediate layer,
2,2-trifluoroethyl methacrylate (3FM)
A copolymer of / 2- (perfluorooctyl) ethyl methacrylate (17FM) / methyl methacrylate (MMA) / methacrylic acid (MAA) = 51/30/18/1 (parts) was supplied.

The material for the core is the inner layer, the material for the sheath is the intermediate layer, the material for the sea is the outer layer, and the other conditions are the same as in Example 1. An optical fiber having a sea-island structure having 37 islands and a sheath portion was manufactured.

The outer shape of the obtained sea-island structure optical fiber is 1
000 μm, the diameter of each core was about 130 μm, and the thickness of the sheath was about 5 μm. The twist angle of the light transmitting island per meter in the longitudinal direction of the optical fiber was 360 degrees. When light was leaked from the side surface of the tube in the same manner as in Example 1, there was almost no unevenness in the amount of light in the longitudinal direction.

Example 3 A compound spinning nozzle having a structure in which a protective layer material introduction portion was provided on the outer peripheral side surface of the inlet portion of the throttle portion of the compound spinning nozzle of Example 1 was used.

As a material for the sea part, 3FM / 17FM /
MMA / MAA = 51/30/18/1 (part) copolymer, and vinylidene fluoride /
A copolymer of tetrafluoroethylene = 72/28 (parts) having a lower melt viscosity at the same temperature than the marine material was used.

The material for the core is introduced into the inner layer nozzle, the material for the sea part is introduced into the outer nozzle, the material for the protective layer is introduced into the protective layer material introduction part, and the other conditions are the same as in the first embodiment. An optical fiber having a sea-island structure having only 37 cores and 37 islands having a protective layer on the outermost periphery was manufactured.

The outer shape of the obtained sea-island structure optical fiber is 1
000 μm, the diameter of each island was about 135 μm, and the thickness of the outermost protective layer was about 20 μm. The twist angle of the light transmitting island per 1 m in the longitudinal direction of the optical fiber is 360.
Degree. When light was leaked from the side surface of the tube in the same manner as in Example 1, there was almost no unevenness in the amount of light in the longitudinal direction. Also, one portion of this tube is 180
The bending was repeated 2000 times (90 degrees left and right), but there was almost no increase in light leakage at the bent portion.

[0033]

As described above, the optical fiber of the present invention can leak light from the side thereof over the entire length thereof without unevenness of the light amount. Since it is independent, light leakage increase due to damage is small. Also, the illumination body in which the optical fiber is accommodated in the tube in parallel has extremely little unevenness in light amount, and it is not necessary to twist the optical fiber at the time of accommodation, so that the optical fiber can be easily loaded into the tube.

Claims (3)

[Claims] An optical fiber having a sea-island structure in which a plurality of light-transmitting island portions are arranged in a sea portion, wherein the light-transmitting island portions are twisted with a twist angle of a predetermined angle or more in a longitudinal direction of the optical fiber. Optical fibers arranged in a matrix. 2. The twist angle per meter of optical fiber is 60.
The optical fiber according to claim 1, wherein the optical fiber has a temperature of at least degree. 3. An illuminating device comprising: an illuminating body accommodating at least one optical fiber according to claim 1 in a transparent tube; and a light source disposed at at least one end of the illuminating body.