JP2914486B2 - Optical fiber and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical fiber.

[0002]

In recent years, the importance of optical communication for transmitting a large amount of information at a very high speed has become extremely important. In Japan, optical fibers have already been laid from Hokkaido to Kyushu. However, there are various problems in expanding this and networking each home.

[0003] For example, the conventional optical fibers made of quartz glass have the following problems. First, an optical fiber made of quartz glass is brittle and easily broken. Further, only those having a diameter of about several μm have been manufactured. For this reason, optical fibers need to be connected or branched. However, when many connections and branches are required, the operation is difficult. By the way, plastic has been proposed as a material for an optical fiber instead of quartz glass. Since this plastic optical fiber can be made with a large diameter, connection and branching operations are easy. It is also flexible. For these reasons, research has been actively conducted in recent years.

FIG. 17 shows a step index (SI) type optical fiber that has been developed so far. This SI optical fiber includes a core 30 and a clad 31. The refractive index of the core 30 is larger than the refractive index of the clad 31. However, since the SI type optical fiber cannot shorten the pulse width, it cannot transmit a large amount of information at a very high speed.

To overcome this, a graded index (GI) type optical fiber has been proposed. still,
As shown in FIG. 18, this GI optical fiber has a refractive index distribution that is continuous along the radial direction of the fiber. For example, in JP-A-62-25705, two or more kinds of vinyl monomers having different refractive indices and reaction ratios and a photopolymerization initiator are placed in a container and photopolymerized, whereby the composition shown in FIG.
8 is obtained. JP 7
No. 56026 discloses a method in which a polymer A having a photoreactive active group and a diffusion solution of a compound B having a lower refractive index than the polymer A are used to diffuse the compound B from the outer periphery of the polymer A into the inside thereof. As a result, a material having a concentration distribution in which the concentration of compound B gradually decreases from the outer periphery to the center is obtained. Thereafter, the photoreactive active group is reacted with Compound B to fix Compound B, thereby obtaining a refractive index distribution type material shown in FIG. In addition, JP-A-62-209402, JP-A-3-192310, WO93 / 195
05 International Patent Publication, JP-A-5-60931,
WO 94/04949 International Patent Publication is also known. In each case, two or more types of polymers (or monomers) are blended or dispersed to obtain a refractive index distribution type material shown in FIG.

It is possible to form an erect equal-magnification image by arraying GI optical fibers and adjusting the length of the lens and the distance from the object plane. Japanese Patent Application Laid-Open No. Sho 6 (1994) describes a long lens arrayed with micro lenses and optical fibers.
JP-A-2-25705, JP-A-5-80981,
It is described in JP-A-3-174105 and the like. By the way, it is said that a material having a refractive index distribution curve represented by the formula (1) is ideal for a refractive index distribution type material (optical fiber).

N = n ₀ (1−ar ² ) (1) where n = refractive index at a position apart from the center of the optical fiber by a radius r n ₀ = refractive index at the center of the optical fiber a = Refractive index distribution constant of optical fiber As can be seen from the comparison between FIG. 18 and equation (1), the conventional GI optical fiber cannot be said to be excellent.

[0008] In many cases, refractive index distribution type materials obtained by mixing two or more polymers having different refractive indices have fluctuations in the refractive index distribution. In addition, the transparency is reduced. Further, light scattering is also likely to occur. Moreover, since continuous production is difficult, it is difficult to obtain a long product. Further, if the diameter of the fiber is small, the brightness is insufficient. Conversely, if the diameter of the fiber is large, an image obtained by arranging a large number of fibers in an array will have a non-uniform degree of image overlap. As a result, a clear image cannot be obtained.

Accordingly, an object of the present invention is to provide a novel optical fiber . In addition, a new optical fiber that is flexible, large, and long can be obtained.
The purpose is to provide ba .

[0010]

[0011]

The object of the present invention is to provide a shaft.
The refractive index changes in the direction from the core to the peripheral side
A made optical fiber, the optical fiber is achieved by an optical fiber which is characterized in that which has been constructed by light irradiation with respect to a material having an atomic group capable of causing photobleaching. Especially from the shaft center
The refractive index changes almost continuously in the direction toward the peripheral side.
The optical fiber is formed by irradiating a material having an atomic group capable of causing photobleaching with light , which is achieved by the optical fiber . .

Or, in the direction from the axis to the peripheral side surface.
Optical fiber whose refractive index changes almost quadratically in
A server, wherein the optical fiber is to be irradiated with light material having an atomic group capable of causing photobleaching
<br/> Thus is achieved in the optical fiber, characterized in that in those constructed. Or, from the shaft center to the peripheral side
Optical fiber whose refractive index changes stepwise in different directions
A server, wherein the optical fiber is to be irradiated with light material having an atomic group capable of causing photobleaching
This is achieved by an optical fiber characterized by comprising:

The material having an atomic group capable of causing photobleaching is preferably a plastic (resin, polymer) from the viewpoint of flexibility. In particular, a polymer having an atomic group capable of causing photobleaching in a main chain and / or a side chain is preferable. For example, a plastic composed of a reaction / polymer of compound A capable of causing photobleaching and polymerizable monomer B, a plastic composed of a reaction product of compound A capable of causing photobleaching and polymer C, Plastics comprising a mixture of the obtained compound A and polymer D are mentioned. Furthermore, a silicon-based resin having Si in the main chain skeleton can also be used.

The compound A capable of causing photobleaching is classified into a compound having a structure in which photobleaching occurs in a molecule and a compound having a structure in which photobleaching occurs between molecules. For example, it has a structure in which light energy is absorbed, electrons move in a molecule (in an atomic group), a double bond is broken, and cyclization can occur. Alternatively, it has a double bond, and further has a structure in which the double bond is easily cyclized in a molecule (atomic group). Such compounds include, for example, aromatic alkylates, hydroaromatic hydrocarbon compounds, bicycloheptane, carboxylic acid derivatives, norbornadiene derivatives, cycloolefin compounds, highly conjugated tropolone compounds, colorless azo compounds, anthracene and Derivatives, aldehydes, ketones and the like can be mentioned.

The polymerizable monomer B reacting with the compound A
Has a double bond or a triple bond. Such compounds include, for example, vinyl compounds, acrylic compounds,
And methacrylic compounds. In addition, p-
Ferenbisethynylbenzene, p-diethynylbenzene, 3,3′-oxydi (p-phenylene) bis2,
A polyphenyl-substituted polyphenylene such as 4,5-triphenylcyclopentadienone or a transparent high-temperature-resistant polymer obtained by subjecting a polyphenylene ether compound to a Diels-Alder reaction can also be used.

[0016] Further, the object of the present invention, the peripheral side surface from the axis
Optical fiber whose refractive index changes in the direction toward
A method of manufacturing a bar, comprising: a material having an atomic group that can cause photobleaching;
This is achieved by a method for manufacturing an optical fiber , which comprises irradiating light in a non-uniform manner in such a direction . Also, axis
The refractive index gradually increases in the direction from the core to the peripheral side.
A manufacturing method of altered optical fiber comprising, prior to the material having an atomic group capable of causing photobleaching
This is achieved by a method for manufacturing an optical fiber , which comprises irradiating light non-uniformly in a direction from the axis to the peripheral side surface. In particular, in the direction from the axis to the peripheral side
The refractive index changes gradually (decrease or increase, or
Is a pulse-shaped) optical fiber manufacturing method,
For a material having an atomic group that can cause photobleaching, the material is uneven in a direction from the axis to the peripheral side surface.
Is achieved by the method of manufacturing an optical fiber, characterized in that one manner of light irradiation.

Further, in the direction from the shaft center to the peripheral side surface,
For manufacturing optical fiber having refractive index gradually changed
A is, by reacting a polymerizable monomer with a compound capable of causing photobleaching to give a material having an atomic group capable of causing photobleaching in the main chain and / or side chains, after which the photobleaching Has a possible atomic group
In the direction from the axis to the peripheral side
Optical fiber, characterized in that the Oite uneven manner light radiation
This is achieved by a method of manufacturing a bus . In particular, on the circumferential side from the shaft center
Refractive index changes stepwise in the direction toward the surface (decrease
Or increased or pulsed) optical fiber
A manufacturing method, by reacting the polymerizable monomer with a compound capable of causing photobleaching to give a material having an atomic group capable of causing photobleaching in the main chain and / or side chains, after which the photobleach Sources that can cause
From the axis to the peripheral side for the material having
Characterized by non-uniform light irradiation in different directions
This is achieved by an optical fiber manufacturing method.

Further, in the direction from the shaft center to the peripheral side surface,
Of optical fiber with refractive index changing almost continuously
A method, wherein a material having an atomic group capable of causing photobleaching is directed toward a peripheral side surface from the axis.
The optical filter is characterized by irradiating light in a non-uniform direction.
This is achieved by a fiber manufacturing method. Especially from the shaft center
The refractive index changes almost continuously in the direction toward the peripheral side.
Optical fiber manufacturing method
The material having an atomic group that can cause photobleaching in a direction from the axis to the peripheral side surface.
Is achieved by the method of manufacturing an optical fiber <br/>, characterized by non-uniform manner the light irradiation are.

Further, in the direction from the shaft center to the peripheral side surface,
Of optical fiber with refractive index changing almost continuously
A method comprising reacting a compound capable of causing photobleaching with a polymerizable monomer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain, and thereafter, the photobleaching is performed. Atoms that can cause
To the peripheral side from the shaft center for the material with the group
Light, characterized in that the non-uniform manner light radiation in the direction
This is achieved by a fiber manufacturing method. In particular, whether the axis
The index of refraction almost continuously in the direction toward the peripheral side from
Method of manufacturing optical fiber with change (decrease or increase)
A is, by reacting a polymerizable monomer with a compound capable of causing photobleaching to give a material having an atomic group capable of causing photobleaching in the main chain and / or side chains, after which the photobleaching Has a possible atomic group
In the direction from the axis to the peripheral side
Optical fiber, characterized in that the Oite uneven manner light radiation
This is achieved by a method of manufacturing a bus .

Also, in the direction from the shaft center to the peripheral side surface,
Of optical fiber with refractive index changing almost continuously
A method comprising adding a compound capable of causing photobleaching to a polymer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain, and thereafter performing the photobleaching. Have an atomic group to gain
Material in the direction from the axis to the peripheral side.
Is achieved by the method of manufacturing an optical fiber <br/>, characterized by non-uniform manner the light irradiation are. Especially, from the shaft center to the peripheral side
Index changes almost continuously in the direction toward
Small or increased) optical fiber manufacturing method.
Te, by adding a compound capable of causing photobleaching the polymer, to obtain a material having an atomic group capable of causing photobleaching in the main chain and / or side chain, thereafter, the follower
For materials with atomic groups that can cause bleaching
Uneven in the direction from the axis to the peripheral side
It is achieved by an optical fiber manufacturing method characterized by light irradiation.

Also, in the direction from the shaft center to the peripheral side surface,
Of optical fiber with refractive index changing almost continuously
A method comprising mixing a compound capable of causing photobleaching and a polymer, and thereafter mixing a material comprising the mixture.
The optical fiber is non-uniformly irradiated with light in a direction from the axis to the peripheral side surface. In particular, from the shaft center to the peripheral side
Index changes almost continuously in the direction
Is a method for producing an optical fiber comprising: mixing a compound capable of causing photobleaching with a polymer; and then mixing the material with the mixture with the shaft core.
This is achieved by a method for manufacturing an optical fiber , which comprises irradiating light non-uniformly in a direction from the surface to the peripheral side surface.

In the direction from the shaft center to the peripheral side surface,
Of optical fiber with refractive index changing almost continuously
A method, peripheral from the axis for the silicone resin having Si in the main chain skeleton capable of causing photobleaching
This is achieved by a method for manufacturing an optical fiber , which comprises irradiating light non-uniformly in a direction toward a side surface. Especially in the direction from the axis to the peripheral side
An optical filter whose refractive index changes (decreases or increases) continuously.
A Aiba manufacturing method, before for the silicone resin having Si in the main chain skeleton capable of causing photobleaching
This is achieved by a method for manufacturing an optical fiber , which comprises irradiating light non-uniformly in a direction from the axis to the peripheral side surface.

[0023]

Optical fiber of the present invention DETAILED DESCRIPTION OF THE INVENTION, the axis
Light whose refractive index changes in the direction toward the peripheral side
A fiber, said optical fiber to light radiation with respect to materials having an atomic group capable of causing photobleaching
It is constituted by doing . Especially from the shaft center
The refractive index changes almost continuously in the direction toward the peripheral side.
Optical fiber that has been converted (decreased or increased)
The optical fiber is formed by irradiating light to a material having an atomic group that can cause photobleaching.
It is . Alternatively, in the direction from the axis to the peripheral side
And the refractive index changes (decreases or increases) almost quadratically
The optical fiber is formed by irradiating light to a material having an atomic group that can cause photobleaching. Or
Refractive index stepwise in the direction from the axis to the peripheral side
Made but changes (decreases or increases, or pulsed)
An optical fiber, wherein the optical fiber irradiates light to a material having an atomic group capable of causing photobleaching.
It is constituted by doing . Optical fiber of the present invention
Is manufactured in the direction from the axis to the peripheral side.
A method for producing an optical fiber in which a refractive index is changed,
Materials with atomic groups that can cause photobleaching
On the other hand, it is uneven in the direction from the axis to the peripheral side.
It is characterized in that light irradiation is performed uniformly. Also, from the shaft center to the peripheral side
The refractive index does not change stepwise in the direction toward the surface.
A method for producing an optical fiber, comprising:
From a material having an atomic group capable of causing
Irradiate light unevenly in the direction toward the peripheral side.
And features. In particular, the direction from the axis to the peripheral side
The refractive index changes stepwise (decrease or increase
Or pulsed) optical fiber manufacturing method.
With atomic groups that can cause photobleaching
In the direction from the axis to the peripheral side
It is characterized by non-uniform light irradiation. Also from the shaft center
The refractive index changes stepwise in the direction toward the peripheral side.
A method for manufacturing an optical fiber, comprising:
Reacting a polymerizable monomer with a compound capable of causing
Photobleaching may occur in the main chain and / or side chain
Obtain a material with atomic group, thereafter, the follower Toburichi
The shaft core for a material having an atomic group capable of causing
Irradiates light unevenly in the direction from
It is characterized by that. In particular, from the shaft center to the peripheral side
The refractive index changes stepwise in the direction (decrease or increase,
Or pulsed) optical fiber manufacturing method.
And compounds that can cause photobleaching and polymerizability
Reacts with monomer and photo-blends on main chain and / or side chain
Material having atomic groups that can cause
Later, having an atomic group capable of causing the photobleaching
Material in the direction from the axis to the peripheral side.
And is characterized by non-uniform light irradiation. Also, shaft core
Almost continuously in the direction from to the peripheral side
A method for manufacturing an optical fiber in which
For materials with atomic groups that can cause bleaching
Non-uniformly in the direction from the axis to the peripheral side
It is characterized by light irradiation. In particular, from the shaft center to the peripheral side
The index of refraction changes almost continuously in the direction
Or increase) the optical fiber manufacturing method,
Materials with atomic groups that can cause photobleaching
On the other hand, it is uneven in the direction from the axis to the peripheral side.
It is characterized in that light irradiation is performed uniformly. Also, from the shaft center to the peripheral side
The refractive index changes almost continuously in the direction toward the surface.
A method for manufacturing an optical fiber, comprising:
Reacting a polymerizable monomer with a compound capable of causing
Photobleaching may occur in the main chain and / or side chain
Obtaining a material having an atomic group, followed by the photobleaching
The shaft core for a material having an atomic group capable of causing
Irradiates light unevenly in the direction from
It is characterized by that. In particular, from the shaft center to the peripheral side
The index of refraction changes almost continuously in the direction (decreasing or increasing).
A method of manufacturing an optical fiber comprising:
Reaction of leaching compound with polymerizable monomer
And cause photobleaching on the main chain and / or side chains.
To obtain a material having an atomic group that can be
Prior to materials with leaching groups
Light unevenly in the direction from the axis to the peripheral side
It is characterized by irradiation. Also, from the shaft center to the peripheral side
Light whose refractive index changes almost continuously in the direction
A method for producing fiber, which involves photobleaching.
A scrutable compound is added to the polymer to form a backbone and / or side chain.
Materials with atomic groups that can cause photobleaching in chains
The resulting, after the charges can cause the Fotoburi Chingu
For the material having atomic groups, from the axis to the peripheral side
Characterized by non-uniform light irradiation in different directions
You. Especially in the direction from the axis to the peripheral side
An optical filter whose refractive index changes (decreases or increases) continuously.
Fiber manufacturing method, which causes photobleaching.
To the polymer, the main chain and / or the side chain
Having an atomic group capable of causing photobleaching on the surface
After which the source capable of causing the photobleaching is obtained.
From the axis to the peripheral side for the material having
Characterized by non-uniform light irradiation in different directions
You. In addition, it is almost continuous in the direction from the axis to the peripheral side.
A method of manufacturing an optical fiber in which the refractive index changes continuously.
Compounds and polymers that can cause photobleaching
And then, for the material consisting of this mixture
Non-uniformly in the direction from the axis to the peripheral side
It is characterized by light irradiation. In particular, from the shaft center to the peripheral side
The index of refraction changes almost continuously in the direction
Or increase) the optical fiber manufacturing method,
Mix a compound that can cause photobleaching with a polymer.
After that, the shaft comprising
Light irradiation non-uniformly in the direction from the core to the peripheral side
It is characterized by doing. Also, from the shaft center to the peripheral side
An optical fiber whose refractive index changes almost continuously in the direction
A method of manufacturing iva, which causes photobleaching
The above-mentioned silicon-based resin having Si in the main chain skeleton is obtained.
Illumination unevenly in the direction from the axis to the peripheral side
It is characterized by shooting. In particular, from the shaft center to the peripheral side
Index changes almost continuously in the direction
Is an optical fiber manufacturing method,
Silicon with Si in the main chain skeleton that can cause bleaching
The direction from the shaft core to the peripheral side with respect to the concrete resin
Is characterized by non-uniform light irradiation.

The material having an atomic group that can cause photobleaching is plastic. Particularly, a polymer in which an atomic group capable of causing photobleaching is present in a main chain and / or a side chain. For example, a plastic composed of a reaction / polymer of compound A capable of causing photobleaching and polymerizable monomer B, a plastic composed of a reaction product of compound A capable of causing photobleaching and polymer C, Plastics comprising a mixture of the obtained compound A and polymer D are mentioned. Furthermore, a silicon-based resin having Si in the main chain skeleton can also be used.

Compound A capable of causing photobleaching
Are classified into those having a structure in which photobleaching occurs in molecules and those having a structure in which photobleaching occurs between molecules. For example, it has a structure in which light energy is absorbed, electrons move in a molecule (in an atomic group), a double bond is broken, and cyclization can occur. Or have a double bond,
Further, it has a structure in which the double bond is easily cyclized in a molecule (atomic group). Such compounds include, for example, aromatic alkylates [eg, 1,2,4-tri-t-butylbenzene, 1,2-dimethylbenzene], hydroaromatic hydrocarbon compounds [eg, 1,2-dimethylbenzene] Dihydrophthalic anhydride, 2-pyrone derivative, 4,5-diphenyl-2-pyrone derivative, 3-hydroxyphthalic anhydride, hydroxycoumarin], anthracene and its derivatives, bicycloheptane, carboxylic acid derivatives [for example,
[2,2,1,0,0] 2,3-dicarboxylate], norbornadiene derivatives, cycloolefin-based compounds [for example, 1,5-cyclohexadiene, 1,5-
Cyclooctadiene, 1,5,5-trimethyldienone, 1,4-diphenylbutadiene, 1,6-diphenylhexatriene, 1,2,3,4,5-pentaphenylcyclohexadiene, 1,3,5 3,8-dimethyloctadiene], a highly conjugated tropolone compound [for example,
[gamma] -tropolone methyl], colorless azo compounds [eg, triazolone], ketones [eg, acetophenone, hexafluoroacetone], aldehydes [eg, trifluoroacetaldehyde], and the like.

The polymerizable monomer B which reacts with the compound A has a double bond or a triple bond. Examples of such compounds include vinyl compounds (for example, styrene, styrene chloride, vinyl acetate, α-methylstyrene, p-chlorostyrene, acrylonitrile, vinyl phenylacetate, vinyl benzoate, vinyl naphthalene, vinylidene chloride),
Acrylic compounds [for example, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, adamantyl acrylate, bornyl acrylate, hydroxyalkyl acrylate, perfluoroalkyl acrylate, diglycerin tetra (meth) Acrylate), methacrylic compounds [eg, adamantyl methacrylate, hydroxyalkyl methacrylate, bornyl methacrylate, naphthyl methacrylate, cyclohexyl methacrylate, ethyl methacrylate, phenyl methacrylate, butyl methacrylate, methacrylonitrile, methyl methacrylate , 2,2,2-
Trifluoroethyl methacrylate, 4-methylcyclohexyl methacrylate, furfuryl methacrylate,
1-phenylethyl methacrylate, 1-phenylcyclohexyl methacrylate, benzyl methacrylate]
And the like.

In addition, polyphenylenes such as p-phenylenebisethynylbenzene, p-diethynylbenzene, 3,3'-oxydi (p-phenylene) bis2,4,5-triphenylcyclopentadienone, etc. Substituted polyphenylene,
Alternatively, the polyphenylene ether compound is replaced with Diels-A
A transparent high-temperature-resistant polymer obtained by the lder reaction can also be used.

Further, the method for producing a gradient index optical material of the present invention is characterized in that a material having an atomic group that can cause photobleaching is irradiated with light nonuniformly. In particular, light irradiation is performed on a material having an atomic group that can cause photobleaching so that the refractive index changes (decreases or increases) almost continuously from the center position toward the outside. Alternatively, light irradiation is performed on a material having an atomic group that can cause photobleaching so that the refractive index changes stepwise (decrease or increase, or pulse). In particular, a compound capable of causing photobleaching is reacted with a polymerizable monomer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain, and thereafter, the refractive index changes stepwise. (Decreasing or increasing, or pulsed).

Further, a compound capable of causing photobleaching is reacted with a polymerizable monomer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain. It is characterized by light irradiation.
In particular, a compound capable of causing photobleaching is reacted with a polymerizable monomer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain. Light irradiation is performed so as to change (decrease or increase) almost continuously toward.

Further, a compound capable of causing photobleaching is added to the polymer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain. It is characterized by doing. In particular, a compound capable of causing photobleaching is added to the polymer to obtain a material having an atomic group capable of causing photobleaching in a main chain and / or a side chain, and thereafter, the refractive index is shifted outward from the center position. Light irradiation so as to change (decrease or increase) almost continuously.

Further, a compound capable of causing photobleaching and a polymer are mixed, and thereafter, light irradiation is performed non-uniformly. In particular, a compound capable of causing photobleaching and a polymer are mixed, and thereafter, light irradiation is performed so that the refractive index changes (decreases or increases) almost continuously from the center position toward the outside. . Further, it is characterized in that a silicon-based resin having Si in a main chain skeleton that can cause photobleaching is irradiated with light non-uniformly. In particular, it is characterized in that a silicon-based resin having Si in a main chain skeleton that can cause photobleaching is irradiated with light so that the refractive index changes (decreases or increases) almost continuously from the center position toward the outside. .

In the present invention, light irradiation (photobleaching) may be performed after the material is formed into a desired shape in advance. Alternatively, the material is irradiated with light (photobleaching)
Then, a desired shape may be obtained. For example, by irradiating ultraviolet light or visible light (photobleaching), an optical material whose refractive index decreases outward from the center position is obtained, and then this is stretched to obtain an optical fiber. Alternatively, an optical fiber may be obtained by irradiating ultraviolet light or visible light (photobleaching) after obtaining a fiber-like material.

After obtaining a film-like material, a microlens array can be obtained by irradiating ultraviolet rays or visible light (photobleaching). In addition, a disk-shaped, plate-shaped, or a shape suitable for various molded products is obtained, and irradiation (photobleaching) is performed by changing irradiation time or light intensity continuously (or discontinuously) depending on the position. In addition, it is possible to obtain a myopic, presbyopia, or bifocal contact lens or a spectacle lens, or a light focusing or light diverging plastic lens suitable for the purpose.

In short, a material having an atomic group capable of causing photobleaching is formed into a material such as a fiber, a rod, a rod, a disk, or the like according to the shape of a target optical element.
After being formed into a lens shape, a plate shape, or a film shape, ultraviolet or visible light is irradiated (photobleaching) so as to have a refractive index distribution of a target optical element. Thereby, a desired optical element is obtained. Alternatively, a material having an atomic group that can cause photobleaching is
After irradiating (photobleaching) ultraviolet light or visible light so as to have the refractive index distribution of the target optical element, the optical element is shaped into the target optical element. This also
The desired optical element is obtained.

The present invention is characterized in that photobleaching based on quantum chemical phenomena is used for controlling the refractive index. Photobleaching is known as a fading phenomenon that occurs when a dye is irradiated with ultraviolet light or visible light.
For example,

[0036]

Embedded image

As can be seen from the photochemical reaction of chromophore (-N
= N-) is broken and H of the phenyl group is obtained, cyclizing and losing the function of coloring. In general, when a compound having a conjugate bond is irradiated with light, a certain electron absorbs light energy to cause a transition (for example, π → π ^* ).
In some cases, a photochemical reaction occurs in the molecule as the electron moves. When the number of double bonds decreases, the maximum absorption wavelength λmax shifts to the shorter wavelength side, and the absorption decreases.

That is, when photobleaching occurs, as shown in FIG. 1, the maximum absorption wavelength λmax shifts to the shorter wavelength side, and the absorption decreases. The extinction coefficient of the substance accompanying the photobleaching changes as shown in the following formulas (2) and (3).

[0039]

(Equation 1)

Therefore, the extinction coefficient of a substance is a function of the bleaching time, temperature, irradiation light intensity, wavelength, and the like. Therefore, the absorbance of the substance can be controlled by changing the bleaching conditions. On the other hand, the change in the refractive index and the extinction coefficient have the relationship of equation (4).

[0041]

(Equation 2)

Therefore, by causing photobleaching, the refractive index decreases in conjunction with changes in the light absorption coefficients α and λmax. Therefore, by selecting bleaching conditions (wavelength and intensity of irradiation light, irradiation time, irradiation position, temperature), it is possible to obtain a refractive index distribution that changes with the square of the radius r. That is, it is possible to obtain an optical material whose refractive index decreases quadratically from the center position to the outside (satisfies the expression (1)).

Meanwhile, an optical fiber is obtained by irradiating ultraviolet rays (or visible light) while rotating the rod, which has been uniformly polymerized, and then drawing it into a fiber. Therefore, an optical fiber can be obtained very easily.
Also, since there is no phase separation, light scattering is small,
There are advantages such as improved transparency. Further, after polymerization, purification can remove a polymerization initiator, a gel component, an unreacted monomer, and the like. Therefore, the optical quality and the mechanical strength can be improved. Further, by using an extruder, an ultraviolet irradiation device, and a stretching machine, particularly, by using a device in which these are combined, a long refractive index distribution type optical fiber can be easily produced.

Light sources used for photobleaching include carbon arc lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, chemical lamps, xenon lamps, laser beams, and the like, which emit light having a wavelength of 150 to 600 nm.

[0045]

Embodiment 1 It is important to understand the relationship between the photobleaching conditions and the refractive index. Therefore, the following preliminary experiment was performed. First, PMMA was synthesized. And 20g
(199.8 mmol) of PMMA was dissolved in tetrahydrofuran (THF). Then, 5 g (33.8 mm
phthalic anhydride) was uniformly mixed. Using this mixed solution, a sample (thin film) having a thickness of 10 μm was produced by a casting method.

Then, the sample was irradiated with light using a light irradiation (photobleaching) apparatus shown in FIG.
The sample temperature during irradiation is 50 ° C and 100 ° C. The wavelength λ of the irradiation light is 0.33 μm, 0.43 μm, 0.53 μm
m. The output of the light source is 70 mW / cm ² . The irradiation time is 400 seconds, 800 seconds, and 1200 seconds. 2, 1 is a light source, 2 and 6 are mirrors, 3 and 4 are lenses, 5
Is a filter, 7 is a sample, and 8 is a table.

The refractive index of the light-irradiated sample 7 was examined, and is shown in FIGS. 3 to 8 (the vertical axis represents the difference Δn in refractive index, and the horizontal axis represents the depth from the surface). FIG. 3 shows the refractive index distribution when the sample temperature during irradiation is 50 ° C. and the wavelength λ is 0.33 μm. In FIG. 3, 1 indicates an irradiation time of 0 second, 2 indicates an irradiation time of 400 seconds, 3 indicates an irradiation time of 800 seconds, and 4 indicates an irradiation time of 1200 seconds.

FIG. 4 shows that the sample temperature at the time of irradiation is 100.
5 shows the refractive index distribution when the temperature is ℃ and the wavelength λ is 0.33 μm.
In FIG. 4, 1 indicates an irradiation time of 0 second and 2 indicates an irradiation time of 400 seconds.
Seconds, 3 is irradiation time of 800 seconds, 4 is irradiation time of 1200
Seconds. FIG. 5 shows the refractive index distribution when the sample temperature during irradiation is 50 ° C. and the wavelength λ is 0.43 μm. FIG.
Among them, 1 is 0 seconds irradiation time, 2 is 400 seconds irradiation time, 3
Indicates that the irradiation time is 800 seconds, and 4 indicates that the irradiation time is 1200 seconds.

FIG. 6 shows that the sample temperature at the time of irradiation is 100
5 shows the refractive index distribution when the temperature is ℃ and the wavelength λ is 0.43 μm.
In FIG. 6, 1 indicates an irradiation time of 0 second and 2 indicates an irradiation time of 400.
Seconds, 3 is irradiation time of 800 seconds, 4 is irradiation time of 1200
Seconds. FIG. 7 shows the refractive index distribution when the sample temperature during irradiation is 50 ° C. and the wavelength λ is 0.53 μm. FIG.
Among them, 1 is 0 seconds irradiation time, 2 is 400 seconds irradiation time, 3
Indicates that the irradiation time is 800 seconds, and 4 indicates that the irradiation time is 1200 seconds.

FIG. 8 shows that the sample temperature at the time of irradiation is 100.
5 shows the refractive index distribution when the temperature is ℃ and the wavelength λ is 0.53 μm.
In FIG. 8, 1 indicates an irradiation time of 0 second, and 2 indicates an irradiation time of 400.
Seconds, 3 is irradiation time of 800 seconds, 4 is irradiation time of 1200
Seconds. The following can be seen from FIGS. (1) In each case, the refractive index continuously changes from the front surface (front surface, light incident surface) of the sample to the back surface of the sample. And the surface of the sample (depth 0)
Has the minimum refractive index. According to the regression analysis, the profile of the refractive index distribution approximates the equation (1). (2) The shorter the wavelength of the irradiation light, the greater the change in the refractive index. Conversely, as the wavelength of the irradiation light increases, the change in the refractive index decreases. (3) The higher the temperature at the time of irradiation, the faster the progress of photobleaching. When the temperature is low, the progress of photobleaching is slow. (4) The change in the refractive index and the irradiation time do not have a linear relationship, but the longer the irradiation time, the larger the change in the refractive index.

Therefore, in the present invention, it is preferable that the conditions for applying light are as follows. The higher the temperature, the faster the bleaching proceeds. However, if the temperature is too high, which greatly exceeds the glass transition temperature Tg, the physical properties of the material may be degraded. Therefore, the temperature is set to Tg−55 ° C. to Tg + 55 ° C. The wavelength of the irradiation light was 0.2 μm to 0.4 μm. When light of a shorter wavelength is used, photobleaching proceeds faster. However, in that case, since many bonds are broken, the damage of the polymer is increased. Therefore,
It is preferable to use one having a wavelength of 0.2 μm or more.

The higher the intensity of the irradiation light, the faster the photobleaching proceeds. For example, if the irradiation light intensity is increased by a factor of 10, the time required for photobleaching to the same depth can be reduced to 1/10. However, too many energies break many bonds. In addition, unnecessary light reactions (for example, decomposition, desorption, etc.) are likely to occur.
Therefore, a light source of about 5 to 700 mW / cm ² is desirable.

As shown in this embodiment, the atomic groups (groups) that can cause photobleaching do not have to be chemically fixed (bonded). However, if not chemically fixed, there may be a problem with long-term stability of performance. Therefore, in Examples 2 to 4, an atomic group (group) capable of causing photobleaching is provided in the main chain or side chain of the polymer.

[0054]

Example 2 15.0 g of trobolone (123.3 mmol
1), 12.5 g of triethylamine (123.3 mmol
l), 13.3 g of methacrylic acid chloride was stirred in 80 ml of THF in a 500 ml four-necked flask and stirred.
(127.2 mmol) was added dropwise. After stirring overnight, the mixture was extracted and purified by a column.

8 g of the obtained ester monomer, 25 g of methyl methacrylate, and 30 mg of a polymerization initiator AIBN were placed in a sealed ampule and polymerized at 65 ° C. for 24 hours. The obtained rod was taken out and both ends were cut. This rod was attached to the light irradiation (photobleaching) device shown in FIG. Then, while rotating the rod at a rotation speed of 1000 rpm, light having a wavelength of 300 nm was irradiated from the peripheral surface of the rod. Incidentally, the intensity of the light source is 70 mW / cm ² . or,
The light source is a high-pressure mercury lamp that emits light having a wavelength of 150 to 600 nm, and the filter emits only light having a wavelength of 300 nm. The temperature during irradiation is 100 ° C.

This light-irradiated rod was set in a cylindrical heating tube, and an optical fiber having a diameter of 0.8 mm was obtained by thermal stretching while performing indirect heating. This optical fiber was transparent. FIG. 9 shows the refractive index distribution of the obtained optical fiber. As a result of examining the refractive index distribution by the method of least squares, the distribution was close to the equation (1).

The light irradiation amount is a distance r from the axis (center).
Are the same if are the same. The amount of light irradiation from the surface (peripheral side surface) toward the center gradually decreases, the change in the refractive index due to photobleaching decreases, and the refractive index increases toward the center. The transparent plastic rod may be irradiated with light after being made into a fiber shape by thermal drawing. However, it is more advantageous to irradiate a large-diameter rod with light and then draw it into a fiber form from the viewpoint of manufacturing efficiency.

[0058]

Example 3 A PMMA polymer having 3-hydroxyphthalic anhydride in the side chain was obtained in the same manner as in Example 2. The ratio of hydroxyphthalic anhydride to MMA is 2
0: 100 (weight ratio). The polymer was purified by reprecipitation.

Next, this purified polymer was dissolved in THF,
A circular sample having a thickness of 0.5 mm and a diameter of 3 cm was prepared by a casting method. Then, it is attached to the apparatus of FIG.
Irradiation with ultraviolet light of 0 nm was performed. In FIG. 10, 11 is a light source, 12 and 13 are lenses, 14 is an aperture mechanism, 15 is a filter, 16 is a sample, and 17 is a motor. Light source 11
Is 700 mW / cm ² . Irradiation temperature is 9
0 ° C. When the aperture mechanism 14 was opened at a speed of 1 mm / min, the difference in refractive index between the center and the periphery was about 0.01.
It was 5.

This can be used as a myopic lens.
Further, when the center of this material was cut off, a stronger concave lens was obtained. And the thickness was made thinner than the conventional lens. That is, as the irradiation time from the central part to the peripheral part decreases, the degree of progress of photobleaching relatively changes, so that a refractive index distribution occurs. Since the refractive index needs to be uniform in the thickness direction, the intensity of the irradiation light is increased.

The degree of the refractive index distribution can be controlled by adjusting the opening speed of the diaphragm mechanism 14. Also, the aperture mechanism 14
Alternatively, a light scattering plate may be used.

[0062]

Embodiment 4 Instead of the aperture mechanism 14 of FIG. 10, for example, a device (FIG. 11) for gradually inflating a black balloon 24 was used. The inflation speed of the balloon 24 is controlled by the gas flow rate to be blown. Gas flow is controlled by mass flow controller 25
Can be freely adjusted within the range of 5 CCM to 500 CCM.

When photobleaching is caused in the sample 16 in this manner, the irradiation time gradually increases from the central portion toward the peripheral portion, so that the refractive index at the central portion is high and the refractive index at the peripheral portion is low. . Thus, the result is a convex lens. In this case, a thin convex lens having a short focal length can be manufactured by shaving the peripheral portion.

Using the polymer synthesized in Example 2, a film having a thickness of 0.3 mm and a diameter of 3.5 cm was formed on a glass substrate by a casting method. Next, this is set in the device of FIG.
Ultraviolet light having a wavelength of 250 nm was irradiated. Incidentally, the intensity of the light source is 700 mW / cm ² . The temperature during irradiation is 90 ° C. The flow rate of the gas for controlling the inflation speed of the balloon 24 is 3
0 CCM. The refractive index difference between the central part and the peripheral part of the obtained sample 16 is about 0.014, and it is a convex lens.

[0065]

Embodiment 5 A similar convex lens can be obtained by using an irradiating device provided with a slidable mass 26 as shown in FIG. 12 instead of the device of FIG. That is, the lumps 26 are
By moving the sample in the left and right direction, the sample 1
12, the irradiation amount varies depending on the position in the vertical direction in FIG. 12, whereby a refractive index distribution type convex lens is obtained.

When a light irradiation device as shown in FIGS. 13 and 14 is used, a device having a corresponding refractive index distribution can be obtained. Reference numeral 27 denotes a light scattering plate. In addition, as shown in FIG. 15, by narrowing the irradiation light and relatively scanning the irradiation light, it is possible to obtain a refractive index distribution type optical material in which the refractive index changes in a pulse shape. Further, if the apparatus shown in FIG. 16 is used, a refractive index distribution type optical material in which the refractive index changes concentrically (pulses in the radial direction) can be obtained.

[0067]

As described above, a novel optical fiber can be obtained. In particular, a graded-index plastic optical fiber that can be easily connected and has a large diameter and can support high-density communication can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in a UV spectrum due to light irradiation (photobleaching).

FIG. 2 Light irradiation (photo bleaching) device

FIG. 3 is a graph showing a refractive index distribution.

FIG. 4 is a graph showing a refractive index distribution.

FIG. 5 is a graph showing a refractive index distribution.

FIG. 6 is a graph showing a refractive index distribution.

FIG. 7 is a graph showing a refractive index distribution.

FIG. 8 is a graph showing a refractive index distribution.

FIG. 9 is a graph showing a refractive index distribution.

FIG. 10: Light irradiation (photo bleaching) device

FIG. 11 is a light irradiation (photobleaching) apparatus.

FIG. 12: Light irradiation (photobleaching) device

FIG. 13: Light irradiation (photobleaching) device

FIG. 14: Light irradiation (photobleaching) device

FIG. 15: Light irradiation (photobleaching) device

FIG. 16: Light irradiation (photobleaching) device

FIG. 17 is an explanatory diagram of an optical fiber.

FIG. 18 is an explanatory diagram of an optical fiber.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G02B 6/12 G02B 6/18 6/18 6/12 N (72) Inventor Hideaki Machida 8154- 217 Uenohara Uenohara-cho, Kitanotsuru-gun, Yamanashi Prefecture Inside the Trichemical Laboratory Co., Ltd. (72) Denshin Nobu, 8154-217 Uenohara Uenohara-cho, Kitatsuru-gun, Yamanashi Prefecture Inside the Trichemical Laboratory Co., Ltd. (56) References JP-A-7-92313 (JP, A) JP-A-6 -240242 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 1/00-3/14 G02B 6/00-6/54

Claims (27)

(57) [Claims] 1. In a direction from a shaft center to a peripheral side surface.
An optical fiber having a changed refractive index, wherein the optical fiber is configured by irradiating light to a material having an atomic group that can cause photobleaching.
An optical fiber which is characterized in that one that is. 2. In a direction from a shaft center to a peripheral side surface.
An optical fiber whose refractive index changes almost continuously.
The optical fiber is configured by irradiating light to a material having an atomic group that can cause photobleaching .
Optical fiber, characterized in that. 3. In the direction from the shaft center to the peripheral side surface.
An optical fiber whose refractive index changes almost quadratically.
Thus, the optical fiber is configured by irradiating light to a material having an atomic group that can cause photobleaching .
Optical fiber, characterized in that. 4. In a direction from a shaft center to a peripheral side surface.
An optical fiber whose refractive index changes stepwise, wherein the optical fiber is configured by irradiating light to a material having an atomic group that can cause photobleaching .
Optical fiber, characterized in that. 5. The optical fiber according to claim 1, wherein the material having an atomic group capable of causing photobleaching is made of plastic. 6. The material having an atomic group capable of causing photobleaching comprises a reaction / polymer of a compound capable of causing photobleaching and a polymerizable monomer. Optical fiber . 7. The light according to claim 1, wherein the material having an atomic group capable of causing photobleaching comprises a reaction product of a compound capable of causing photobleaching and a polymer. Fiber . 8. The optical fiber according to claim 1, wherein the material having an atomic group capable of causing photobleaching comprises a mixture of a compound capable of causing photobleaching and a polymer. . 9. The material according to claim 1, wherein the material having an atomic group capable of causing photobleaching is a silicon resin having Si in a main chain skeleton.
Optical fiber . 10. The optical fiber according to claim 1, wherein the atomic group capable of causing photobleaching is in a main chain and / or a side chain of the polymer. 11. The optical fiber according to claim 6, wherein the compound capable of causing photobleaching has a structure in which photobleaching occurs in a molecule. 12. The compound capable of causing photobleaching has a structure capable of absorbing light energy, cutting a double bond, and causing cyclization. One of the optical fibers . 13. The compound capable of causing photobleaching has a double bond, and further has a structure in which the double bond is easily cyclized in the molecule. One of the optical fibers . 14. The optical fiber according to claim 6, wherein the compound capable of causing photobleaching has a structure in which photobleaching occurs between molecules. 15. Compounds capable of causing photobleaching include aromatic alkylates, hydroaromatic hydrocarbon compounds, bicycloheptane, carboxylic acid derivatives, norbornadiene derivatives, cycloolefin compounds, highly conjugated tropolone compounds, and colorless The optical fiber according to any one of claims 6 to 8, wherein the optical fiber is at least one selected from the group consisting of an azo compound, anthracene and a derivative thereof, an aldehyde, and a ketone. 16. The optical fiber according to claim 6, wherein the polymerizable monomer has a double bond or a triple bond.
Aiba . 17. A scent in a direction from a shaft center to a peripheral side surface.
This is a method of manufacturing an optical fiber in which the refractive index changes due to
A method for producing an optical fiber , comprising irradiating a material having an atomic group capable of causing photobleaching nonuniformly in a direction from the axis to a peripheral side surface. 18. A scent in a direction from a shaft center to a peripheral side surface.
For manufacturing optical fiber having refractive index gradually changed
A method of manufacturing an optical fiber , comprising irradiating a material having an atomic group capable of causing photobleaching non-uniformly in a direction from the axis to a peripheral side surface. 19. A scent in a direction from a shaft center to a peripheral side surface.
For manufacturing optical fiber having refractive index gradually changed
A is, by reacting a polymerizable monomer with a compound capable of causing photobleaching to give a material having an atomic group capable of causing photobleaching in the main chain and / or side chains, after which the
Materials with atomic groups that can cause photobleaching
A method of manufacturing an optical fiber , comprising irradiating light non-uniformly in a direction from the axis to a peripheral side surface. 20. A scent in a direction from a shaft center to a peripheral side surface.
Of optical fiber with refractive index changing almost continuously
A method for producing an optical fiber , comprising irradiating a material having an atomic group capable of causing photobleaching non-uniformly in a direction from the axis to a peripheral side surface. 21. In the direction from the shaft center to the peripheral side surface.
Of optical fiber with refractive index changing almost continuously
A method, by reacting the polymerizable monomer with a compound capable of causing photobleaching to give a material having an atomic group capable of causing photobleaching in the main chain and / or side chains, after which the
Materials with atomic groups that can cause photobleaching
A method of manufacturing an optical fiber , comprising irradiating light non-uniformly in a direction from the axis to a peripheral side surface. 22. In the direction from the shaft center to the peripheral side surface.
Of optical fiber with refractive index changing almost continuously
A method, by adding a compound capable of causing photobleaching the polymer, to obtain a material having an atomic group capable of causing photobleaching in the main chain and / or side chain, after this, the Fotobu
Prior to materials with leaching groups
A method for manufacturing an optical fiber , comprising irradiating light non-uniformly in a direction from the axis to a peripheral side surface. 23. In the direction from the shaft center to the peripheral side surface.
Of optical fiber with refractive index changing almost continuously
A method comprising mixing a compound capable of causing photobleaching and a polymer, and thereafter, mixing the material comprising the mixture with the shaft.
A method for manufacturing an optical fiber , comprising irradiating light non-uniformly in a direction from a core to a peripheral side surface. 24. In the direction from the axis to the peripheral side surface.
Of optical fiber with refractive index changing almost continuously
A method, toward the peripheral side surface from the axis for the silicone resin having Si in the main chain skeleton capable of causing photobleaching
Light, characterized in that the non-uniform manner light radiation in the direction
Fiber manufacturing method. 25. The method for manufacturing an optical fiber according to claim 17, wherein light having a wavelength of 0.2 μm to 0.4 μm is irradiated. 26. The method for manufacturing an optical fiber according to claim 17, wherein light having an intensity of 5 to 700 mW / cm ² is irradiated. 27. The material to be irradiated with light is Tg-55 ° C. to T
The optical fiber according to any one of claims 17 to 26, wherein the temperature is maintained at g + 55 ° C (Tg is a glass transition temperature).
Fiber manufacturing method.