JPS63106705A - Manufacture of plastic light transmitting body - Google Patents

Abstract

PURPOSE:To afford heat resistance and solvent resistance to a light transmitting body by forming a continuous concn. gradient by diffusing and penetrating a monomer for forming a polymer having lower refractive index then the refractive index of a transparent gel from the surface of a rod or substrate comprising the transparent gel to the inside of the rod or substrate. CONSTITUTION:A rod or substrate comprising transparent gel is formed by polymerizing a part of monomers M1 for forming a polymer P1 wherein at least one kind of the monomers comprises an org. carboxylic acid salt. Thereafter, monomers M2 for forming a polymer P2 having a lower refractive index than the refractive index of the transparent gel, are diffused into the inside of the rod or the substrate to provide a concn. gradient continuously, wherein the monomers M2 has the characteristic of forming ionic bonds or coordinate bonds with at least one metal ion. Thus, the polymers. of the monomers M1 and M2 are completed. By this constitution, a plastic light transmitting body having heat resistance, solvent resistance, and possibility for affording novel functionality, is obtained, which is useful as a material for refractive index distributing type focussing optical fiber, optical waveguide, or refractive index distributing type lens, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a light-focusing optical fiber having a refractive index distribution,
The present invention relates to a method of manufacturing a synthetic resin optical transmission body such as an optical waveguide or a gradient index lens.

[Conventional technology]

In recent years, various types of optical transmitters made of synthetic resins in addition to glass have been developed from the viewpoint of good processability and ease of handling1. Applications are expanding to the field of equipment. These transmission bodies include step-index type, which consists of a core part with a relatively high refractive index and a cladding layer with a relatively low refractive index, and a refractive index type, in which the refractive index increases continuously from the periphery toward the central axis. There are two types of grated index type with a distribution, and recently a transmitter with the latter structure has been developed using a synthetic resin.

The methods for manufacturing synthetic resin optical transmitters that have been proposed so far include a method in which monomers with different refractive indexes are internally diffused into a semi-gelled synthetic resin material and polymerized (Optics, Vol. 10, No. 2). (1981), pp. 105 to 110), two types of monomers with different refractive indexes are mixed and prepolymerized, the unpolymerized monomers are selectively volatilized from one surface, and then one polymerization is carried out again. A method of changing the refractive index by
No. 64) A method of extracting a specific component from a synthetic resin body consisting of a mixture of two or more transparent polymers having different refractive indexes using a solvent, (Japanese Unexamined Patent Publication No. 47-28059) Copolymerization reactivity of monomers A method of forming concentration distribution by photopolymerization using differences in ratio, (Optics, Vol. 12, No. 6 (198
3) Pages 470 to 475) Alternatively, high refractive index metal ions in the synthetic resin body are desorbed.

Method for forming concentration distribution of metal ions (Unexamined Japanese Patent Publication No. 51-4
No. 2545).

[Problems to be solved by the invention] However, since the optical transmission bodies produced by these manufacturing methods use a special monomer composition to form a refractive index distribution, they have problems in terms of heat resistance and solvent resistance. No consideration was given to this, and there were problems with long-term reliability. Furthermore, optical transmission bodies are passive, and it is difficult to add any functionality to them.

The purpose of the present invention is to manufacture synthetic resin optical transmission bodies such as gradient index focusing optical fibers, guiding waveguides, gradient index lenses, etc., which have heat resistance, solvent resistance, and the possibility of imparting new functionality. The purpose is to provide a method.

[Means for solving problems]

For the above purpose, we focused on a transparent synthetic resin containing a special metal as a material that has the potential to impart heat resistance, solvent resistance, and new functions, and conducted intensive research into methods that can form a refractive index distribution in this resin. As a result of stacking, a polymer P with a refractive index of Ni
A transparent gel-like Rondo is produced by partially polymerizing monomer Mz, at least one of which is an organic carboxylic acid metal salt, to produce I.

Alternatively, after forming the substrate, an ion or a monomer capable of forming a coordinate bond with one or more metal ions that generate a polymer P1 that gives a refractive index N2 lower than the refractive index Nl of the transparent gel from the outside. Mz is diffused into the interior to continuously form a concentration gradient, and the monomer N! and by completing the polymerization of N2.

[Effect]

In the present invention, the monomer M1, at least one of which is an organic carboxylic acid metal salt, is a transparent monomer containing at least a structural formula represented by general formula (1), is a hydrogen atom or a methyl group, M is a metal element, n
(haha metal valence; Rz represents a group having 4 or more carbon atoms)
A transparent monomer with a high refractive index can be obtained by introducing a benzene ring or a group containing a halogen other than fluorine into Rz. In addition, if a partially unsaturated axial bond is introduced into Rt, a network polymer can be formed by ionic crosslinking, so a transparent gel-like substrate can be easily formed in the same way as a network polymer made of conventional polyfunctional monomers. can do. In this case, a network polymer can also be formed by crosslinking both ionic and covalent bonds using both monomers. Furthermore, since the synthetic resin obtained by polymerizing this monomer has bulky molecules ionically bonded to the polymer side chains, crystallization of the resin can be suppressed.
Optical transparency is significantly improved compared to the case of using an ionomer made of an ethylene-methacrylic acid copolymer and metal ions described in Japanese Patent No. 42545. Examples of this include the metal-containing transparent monomer disclosed in JP-A-60-181107.

This monomer M1 is formed into a gel-like form by a known method into a fiber, rod, or plate shape depending on the type of the intended optical transmission medium.For example, in the case of an optical fiber, a chemical agent such as Teflon or polyethylene The monomer M1 is injected into an inert tube, prepolymerized, and continuously extruded from the tube.The prepolymerization of the monomer Mz is performed when the polymer has lost its fluidity and becomes a transparent gel, that is, Select conditions such that polymerization is terminated in an incomplete state.

Next, these gel-like rondos or substrates are bonded ionicly or coordinately to one or more metal ions that produce a polymer P2 that gives a refractive index N2 lower than the refractive index Nl of the transparent gel. Diffuse and permeate the wet monomer M2 into the interior. In this case, either a method of impregnating the liquid monomer M2 with a gel-like material or a method of vaporizing the monomer M2 and diffusing and permeating the monomer M2 into the interior in the form of vapor can be used.

In the present invention, the monomer M2 is specifically a low refractive index monomer having at least one type of group selected from a hydroxyl group, an epoxy group, or an orboxy group and an unsaturated bond. Examples of these are hydroxyalkyl methacrylate, hydroxyalkyl acrylate, glycidyl acrylate, glycidyl methacrylate, acrylic acid,
Examples include methacrylic acid. These can be used alone or in combination of two or more. In addition, when a normal low refractive index monomer such as methacrylic acid ester, acrylic acid ester, fluorinated methacrylic acid ester, fluorinated acrylic acid ester, or vinyl acetate is used as the monomer M2, after diffusion and penetration, The resin becomes slightly opaque. Conventionally,
Gel-like substances made of metal-containing monomers are not compatible with ordinary monomers, and furthermore, these monomers have weak interaction with metal ions, so after completing polymerization, the metal-containing monomers are Because the gel and the impregnating monomer polymerize independently,
Due to the difference in refractive index, some cloudiness occurs and transparency is poor. Therefore, as the monomer M2, a monomer that has strong interaction with metal ions is essential. However, in order to adjust the refractive index, if necessary, it is possible to mix and use ordinary monomers such as fluorinated methacrylic acid esters with these monomers.

The immersion or diffusion operation is stopped when the monomer Mz has diffused to the central axis of the gel-like material, or after some time has elapsed, and the gel-like material is mixed with the monomer M.
An operation is performed to prevent z from volatilizing to the outside, and the polymerization is completed together with monomer M2. Methods to prevent the monomer M2 from being volatilized to the outside include, for example, wrapping the gel-like material in a plastic film or plate after the diffusion operation, or immersing the monomer Mz in it, or under steam. Monomer M2 in the present invention has a method of completing the polymerization as it is. Generally, many of them have a high monopolymerization rate, so they are particularly convenient for preventing volatilization.

It has been found that synthetic resin optical transmission bodies having various shapes and performances can be obtained by the manufacturing method of the present invention as described above.

These synthetic resin optical transmitters have metal ions and molecules that strongly interact with metal ions in their molecules, so they have excellent heat resistance and solvent resistance. Regarding moisture resistance, 1) it is considered to be slightly inferior to ordinary synthetic resins; 1) the resin of the present invention has hydroxyl groups, carboxyl groups, and epoxy groups strongly ionic or coordinate bonded to metal ions; Since it is possible to manufacture products that contain a benzene ring, which is a hydrophobic group, it is not affected greatly, and it is also possible to protect the surface with other synthetic resin plates or membranes that have excellent moisture resistance. .

Next, some of these specific examples will be explained using drawings.

Figure 2 is an example of a fibrous optical transmission body whose refractive index decreases continuously from the central axis toward the periphery, and light 2 incident from the end face of the transmission body 1 is totally reflected inside. Without,
It progresses in a continuous self-focusing manner.

FIG. 1 is an example of an optical waveguide created in a plane, and is shown in a cross-sectional view of a synthetic resin. A mask made of a metal or organic thin film is prepared on the gel-like substrate 3 made of the alloy scrap transparent monomer (a), and then immersed in the low refractive index monomer 5Mg to be diffused and permeated.

After that, the polymerization of the gel-like base and monomer M2 is completed,
The optical waveguide 6 is manufactured.

The third @ is an example of a gradient index lens in which the refractive index decreases continuously from the central axis toward the lateral side.

〔Example〕

The present invention will be explained below with reference to examples and figures.

<Example 1> 0.1218 mol of acrylic acid and 0.0656 mol of cinnamic acid were dissolved in benzene LoomΩ, and 0.0423 mol of barium hydroxide monohydrate (Ba (OH)z・HzO) was dissolved at room temperature. It reacted gradually. This composition contains 50 parts by weight (
25 parts of vinyltoluene,
After adding 25 parts of glycidyl methacrylate, water and benzene, which were reaction compounds, were distilled off under reduced pressure to obtain a metal-containing transparent monomer. Dissolve 0.2 parts of similistilperoxydicarbonate in 100 parts of this monomer, and prepare a mixture with an inner diameter of 1 m and a length of 1 m.
After curing at 60° C. for 1.5 hours, the fibrous transparent gel polymer was taken out. Thereafter, this gel polymer was immersed in a solution of 75 parts of glycidyl methacrylate and 25 parts of 2-hydroxybutyl methacrylate containing 0.2 parts of cimilistyl peroxydicarbonate, and left at room temperature for 2 hours. Take it out, fix both ends, and heat it for 70 minutes in a vapor atmosphere of monomer for impregnation.
m4 hours, then.

It was cured by heating at 80 m for 5 hours in a nitrogen atmosphere.

A cross-section of the obtained fibrous polymer was cut out to a thickness of 1 m, and was examined using an interference microscope (Interfayu manufactured by Carl Zeiss).
When the maximum refractive index difference was measured, it was 0.021. It was also confirmed that when the end face is polished to be a plane perpendicular to the central axis and light is incident from one end of the fiber, the light travels in a self-focusing manner without being totally reflected inside the rod. . When the optical loss of this fiber was measured, it was found that Hs
-Ne laser light was 0.8 dB/m. When this fiber was left at 120° C. for 1,000 hours and the optical loss was measured again, it was 0.9 dB/km, and the change was small.

From the above, it was confirmed that this fiber can be used as an optical transmission body having the structure shown in FIG.

<Example 2> 0.2 parts of cimilistyl peroxydicarbonate was dissolved in 100 parts of the metal-containing transparent monomer obtained in Example 1, poured into a silicone-released glass plate, and heated at 60°C for 1 hour. A transparent gel substrate of 40 x 20 x 2 nn was prepared by leaving it as it was 6
Next, on both sides of this gel substrate, a width l1111 and a length 40
, 40 parts of glycidyl methacrylate containing 0.3 parts of cimilistyl peroxydicarbonate and 10 parts of acrylic acid were placed in close contact with each other using two metal films with a thickness of 0.1 mm as a mask.
Department.

After immersing it in a solution of 50 parts of trifluoroethyl methacrylate and leaving it at room temperature for four hours, the transparent substrate was removed, and a 22 m thick polydiethylene glycol bisallyl carbonate plate and a 2 m thick glass plate were placed on the outside. It was crimped and fixed with a spring clip through the plate. After heating and hardening this substrate for 70 m@3 · hours and 80 m@3 · hours, the glass plate was removed to obtain a sandwich-structured leading waveguide.

The cross section of the obtained transparent plate 7 was cut and polished to a thickness of 1 m+, and the state of refraction distribution was examined using an interference microscope. The refractive index of the two waveguide sections was highest at the central axis and decreased continuously toward the periphery. The maximum refractive index difference is 0.036
Met. It was also confirmed that when the end face of a transparent plate was polished and light was incident from one end, the light traveled through the area covered by the mask while bending without being totally reflected.

From the above, it can be seen that this transparent plate forms an optical waveguide portion as shown in FIG.

〔Effect of the invention〕

According to the present invention, a synthetic resin optical transmission body such as a gradient index focusing optical fiber, an optical waveguide, or a gradient index lens, which has heat resistance, solvent resistance, and the possibility of imparting new functionality. A manufacturing method is obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an optical transmission body having optical waveguide portions with different refractive indexes inside a plane according to an embodiment of the present invention, and Fig. 2 shows a continuous decrease in refractive index from the central axis toward the periphery. FIG. 3 is a characteristic diagram of the fiber-like optical transmission body shown in FIG. 3, which shows a gradient index lens in which the refractive index decreases continuously from the central axis toward the periphery.

Claims (1)

[Claims] 1. (a) Monomer M, at least one of which is an organic carboxylic acid metal salt, which forms a polymer P_1 having a refractive index of Ni.
A process of partially polymerizing _1 to form a transparent gel-like rod or substrate. (b) Ionically or coordinately bonding from the surface of the transparent gel-like rod or substrate with one or more metal ions that produce a polymer P_2 that gives a refractive index N_2 lower than the refractive index Ni of the transparent gel. A process of continuously forming a concentration gradient by diffusing and penetrating the liquid monomer M_2 into the interior. (c) A method for producing a synthetic resin optical transmission body, comprising the step of completing the polymerization of the monomer M_1 and the monomer M_2. 2. The monomer M_2 is a monomer having an unsaturated bond and at least one group selected from a hydroxyl group, an epoxy group, or a carboxyl group. A method for manufacturing a synthetic resin optical transmission body.