JPH0381701A - Manufacturing method of plastic optical transmitter - Google Patents

Abstract

PURPOSE:To allow continuous production by subjecting a yarn-shaped body made of monomers which can form a low-refractive index polymer and a high- refractive index polymer to an evaporation treatment of the monomers within a porous body. CONSTITUTION:A mixture 1 composed of the polymer A, such as polymethyl methacrylate, and the monomer B, such as methyl methacrylate, which polymer has the refractive index higher than the refractive index of the polymer A is inserted into a cylinder 3 and is extruded from a nozzle 4 having the porous part 5 by a piston 2. The monomer B is evaporated through the porous part 5 from the boundary between the mixture 1 and the porous part 5 to form a continuous concn. distribution from the central part to the outer peripheral part of the fiber shape in the porous part 5 at this time. The mixture is then polymerized in a part 7 for irradiation with active rays to obtain the optical transmission body 9. The optical transmission body is thus continuously pro duced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a plastic optical transmission device having a continuous refractive index distribution from the center to the outer periphery, which is used in a light-focusing lens, a light-focusing fiber, etc. The present invention relates to a method of manufacturing a body.

[Prior Art and Problems to be Solved] As an optical transmission body having a continuous refractive index distribution from the center to the outer periphery, a glass one has already been proposed in Japanese Patent Publication No. 47-816. However, optical transmission bodies made of glass have problems in that they have low productivity, are expensive, and have poor flexibility.

Several methods have been proposed for manufacturing a plastic optical transmission body in contrast to such a glass optical transmission body. The manufacturing methods of plastic optical transmitters having a continuous refractive index distribution from the center to the outer periphery can be roughly divided into (
1) A synthetic resin rod made of an ionically crosslinked polymer in which the concentration of metal ions varies continuously from the central axis toward the surface (Japanese Patent Publication No. 47-26913), (2) refractive index A synthetic resin rod made from a mixture of two or more different transparent polymers is treated with a specific solvent to partially dissolve and remove at least one of the constituent acid components of the synthetic resin rod. (Special Public Service 1977)
-28059 Publication), (3) Two types of monomers with different refractive indexes are polymerized by devising a polymerization method to create a continuous refractive index distribution from the surface to the inside (Japanese Patent Publication No. 5
4-30301), (4) A monomer having a lower refractive index than the surface of the crosslinked polymer is diffused and arranged so that the content of this monomer changes continuously from the surface to the inside, and then polymerized. with a refractive index distribution (
Special Publication No. 52-5857, Special Publication No. 56-37521
and (5) diffuse and react a low-molecular compound having a refractive index lower than that of the polymer from the surface of the reactive polymer so as to provide a continuous refractive index distribution from the surface to the inside. What to do (Special Public Interest Publication 57-2968
Publication No. 2) etc.

A common problem with these conventional methods is that processes such as diffusion and extraction take a long time and are limited in length, so the production process is intermittent, in other words, it is a batch production method. These manufacturing methods each have their own problems as an industrial technology, such as extremely low productivity, extremely difficult selection of manufacturing conditions, and inability to achieve reproducibility.

[Means for Solving the Problems] Therefore, the present inventors solved the irrationality caused by the intermittent production process of the above-mentioned conventional technology, and made continuous production similar to glass or plastic optical fibers possible. We are currently investigating a method for manufacturing a graded index plastic optical transmitter, which is more simple than a filament made from a low refractive index polymer and a monomer that can form a high refractive index polymer. We are currently considering a method to equalize the volatilization rate of mass.
The present invention was completed based on the discovery that the object can be achieved by subjecting the filament to a monomer volatilization treatment within a porous body.

That is, the gist of the present invention is to extrude a mixture of a polymer (A) and a monomer (B) whose refractive index becomes higher than that of the polymer (A) after polymerization through a nozzle having a porous part, In the step of shaping into a fiber, the monomer (B) is volatilized from the porous portion and a concentration distribution of the monomer (B) is formed from the center to the outer periphery of the fiber, and then Alternatively, there is provided a method for producing a plastic light transmitting body having a continuous refractive index distribution from the center to the outer periphery, which is characterized by polymerizing while forming the body.

An example of the manufacturing method of the present invention will be explained with reference to FIG.

A mixture (1) of monomer (A) and monomer (B) whose refractive index becomes higher than that of polymer (A) after polymerization is placed in a cylinder (
3) into the porous part (5) by means of the piston (2).
At this time, in the porous part (5), the monomer (B) is volatilized from the interface between the mixture (1) and the porous part through the porous part, and is extruded into a fiber-like form. A continuous concentration distribution is formed from the center to the outer periphery of the object. Next, polymerization occurs in the actinic ray irradiation section (7), and the desired light transmitting body (9) is continuously obtained by the nip roller (8).

Examples of the polymer (A) used in carrying out the present invention include polymethyl methacrylate, methyl methacrylate/fluoroalkyl (meth)acrylate copolymer, vinylidene fluoride copolymer perfluoroalkyl (meth)acrylate polymer, etc. Polymer (A)
Examples of the monomer (B) that can provide a polymer with a higher refractive index than that of methyl methacrylate, benzyl methacrylate, phenyl methacrylate, adamantyl methacrylate, and styrene.

At this time, in order to promote volatilization of the monomer (C) from the fiber form through the porous part, a method such as heating the porous part or suctioning it through the suction port (6) to bring it into a reduced pressure state is used. is valid. Further, the porous portion is made of a sintered body of metal or ceramic, and the pore diameter of the porous body is preferably 101 m or less, and the pores must be continuous. By volatilizing the monomer (C) from a fiber-like material using such a porous body, the volatilization rate becomes extremely uniform compared to the conventional technique, and the refractive index distribution can be made uniform.

In addition, the fiber-like material that has been given a refractive index distribution by the above treatment is polymerized by irradiation with actinic rays.
) is desirable to introduce a gas such as nitrogen or argon gas.

Next, the present invention will be explained in detail with reference to Examples.

[Examples] Example 1 50 parts by weight of copolymer (n·-1,455, [η]-2,9) of 50 parts by weight of methyl methacrylate and 50 parts by weight of 2.2.3.3-tetrafluoropropyl methacrylate part and methyl methacrylate (n·-1,489 of the polymer
) and 1 part by weight of 1-hydroxycyclohexylphenylketone were placed in the cylinder shown in FIG.
3) Mix it uniformly and push it out from the nozzle (4) with the piston (2). At this time, the porous part (5) made of ceramic sintered body is heated to 50°C and the passage time is 15 minutes. The methyl methacrylate is volatilized as a fiber to form a fiber-like material, and the actinic light irradiation section (7
), irradiated with ultraviolet rays for 1 minute using three low-pressure mercury lamps for polymerization to obtain a light transmitting body with a diameter of 1.

When the refractive index distribution of this light transmitting body was measured using an interfaco interference microscope, the refractive index at the center was 1.470 and the refractive index at the outer periphery was 1.463, which varied continuously from the center to the outer periphery.

Further, when this optical transmission body was cut into 8-length pieces, both ends of which were polished and the image was observed, an inverted real image was observed.

Example 2 In Example 1, the porous part (5) was passed through the suction port (6) with a vacuum pump for 15 minutes at room temperature under reduced pressure.
Except for this, an optical transmission body having a diameter of 1 mm was obtained in the same manner as in Example 1.

When the refractive index distribution of this light transmitting body was measured using an interfaco interference microscope, the refractive index at the center was 1.470 and the refractive index at the outer periphery was 1.460, which varied continuously from the center to the outer periphery.

Further, when this optical transmission body was cut into 8-length pieces, both ends of which were polished and the image was observed, an inverted real image was observed.

Example 3 30 parts by weight of benzyl methacrylate, 50 parts by weight of methyl methacrylate, 50 parts by weight of polymethyl methacrylate and 1 part by weight of 1-hydroxycyclohexylphenyl ketone
Parts by weight of the mixture were prepared in the same manner as in Example 1 to obtain an optical transmission body having a diameter of 1.

When the refractive index distribution of this light transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1.505 and the refractive index at the outer periphery was 1.495, and it was found to change continuously from the center to the outer periphery.

Furthermore, when this optical transmission body was cut into five lengths and both ends were polished and the image was observed, an inverted real image was observed.

[Effects of the invention] The manufacturing method of the present invention solves the irrationality caused by the intermittent production process that existed in the conventional technology, and makes it possible to continuously produce an optical transmission body with uniform characteristics. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of manufacturing a plastic optical transmission body of the present invention. 2... Piston 3... Cylinder 4... Nozzle 5... Porous portion 7... Actinic ray irradiation section 8... Nip roller 9... Light transmission body

Claims (1)

[Claims] In the step of extruding a mixture of a polymer (A) and a monomer (B) whose refractive index is higher than that of the polymer (A) after polymerization through a nozzle having a porous part and shaping it into a fiber shape, , from the center to the periphery, characterized in that the monomer (B) is volatilized from the porous part and polymerized after or while forming a concentration distribution of the monomer (B) from the center to the periphery. A method for manufacturing a plastic optical transmission body having a continuous refractive index distribution throughout the area.