JPH1054918A - Optical waveguide and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily and simultaneously form transmission paths of plural circuits on a supporting body by boring a long-sized base material made of a thermoplastic resin with fine grooves extending in a longitudinal direction by a revolving roll, packing a transparent resin precursor for forming the transmission paths therein and curing this precursor. SOLUTION: The optical waveguide 1 is formed by boring the longsized base material 2 with plural pieces of the fine grooves 3 extending in the longitudinal direction is parallel, packing the transparent resin precursor into the fine grooves 3, 3 and curing this resin precursor, thereby forming the transmission paths 4, 4. A cover film 5 is affixed atop this optical waveguide to protect the transmission paths 4, 4. The base material 2 is not particularly restricted, insofar as the materials allow the formation of recessed parts by the roll. More preferably, the materials are thermoplastic resins, for which polyester, polyamide, polypropylene, fluororesins, polyvinyl chloride, methacrylic resins, acetal resins, etc., are used. The thickness of the base material 2 is preferably selected from a range of 100μm to 1cm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical waveguide and a method for manufacturing the same. More specifically, the present invention relates to an optical waveguide suitable for continuously forming an optical waveguide on a sheet and a method for manufacturing the same. Since optical fibers of a plurality of lines can be simultaneously formed on a support, manufacturing costs are significantly reduced. Is done. Further, since a plurality of sheet-like optical fiber cables can be formed, it is easy to lay the transmission line in a room such as a wall surface or a ceiling surface.

[0002]

2. Description of the Related Art At present, an information signal transmission system is being replaced by an optical signal transmission system suitable for high reliability, high speed and large capacity. For example, a single-mode glass fiber is used in a conventional trunk transmission line. However, optical fiber made of single mode glass fiber,
The connection requires precision, and the device to be connected is expensive. Therefore, when using the single-mode glass fiber method, in order to increase the efficiency, signals from many ends are mixed by a time-division method or the like, and high-speed transmission is performed.
Near the receiving end, the signal is separated again into the original signal,
The equipment is getting larger and larger. On the other hand, there are many usage modes in which the connection speed with the terminal is not required to be as high as that of the trunk line, and the transmission distance is short.

[0003] For such an optical transmission line at the end, an optical transmission line that can be easily wired at low cost is required. Also,
Since the number of lines required for wiring increases, the terminal optical transmission line uses multimode coherent light which can be manufactured at low cost, and uses an organic optical fiber (POF). Multi-mode optical fibers do not require a diameter as small as single-mode glass fibers, and emphasis is placed on ease of connection, and those with diameters of 10 μm to several 100 μm are beginning to be put into practical use. However, at present, the only method of manufacturing POF is a method of making optical fibers one by one and bundling them into a plurality of lines.

Conventionally, as a means for forming an optical transmission path in a plane parallel on a resin serving as a support, a flat support,
For example, on a sheet of PMMA or the like, a resist layer corresponding to a negative image of a desired optical transmission path is formed by a photofabrication method, and a depression is formed by a dry etching method, and the material for forming the optical transmission path in the depression is formed. A resin material, for example, a monomer such as polysiloxane is charged, and then the monomer is cured to form a waveguide. According to this method, a complicated process of photofabrication is required, so that it is very expensive, and the size that can be manufactured is limited by a dry etching apparatus.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical waveguide in which a plurality of optical transmission lines can be easily formed simultaneously on a support. It is another object of the present invention to provide a manufacturing method for facilitating the enlargement of an optical waveguide having a plurality of lines.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies for the above-mentioned purpose, and as a result, an excellent optical waveguide can be easily manufactured by providing a concave portion for a transmission line in a base material by an embossing method. The inventors have found that the present invention can be performed, and have reached the present invention. That is, in the present invention, a narrow groove extending in the longitudinal direction is formed by a rotating roll on a long base material made of a thermoplastic resin, and the narrow groove is filled with a transparent resin precursor that forms a transmission path, and cured. It is intended to provide an optical waveguide characterized by comprising: and a method for producing an optical waveguide comprising the following steps (a) to (c). (A) forming a narrow groove extending in the longitudinal direction using a roll on a long base material; (b) filling a transparent resin precursor into the narrow groove; and (c) curing the transparent resin precursor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an optical waveguide 1 according to the present invention is provided on a long base material 2 with narrow grooves 3 and 3 extending in the longitudinal direction.
Are formed in parallel with each other, and after filling the narrow grooves 3 and 3 with a transparent resin precursor, the transparent resin precursor is cured and the transmission path 4,
4 is formed. In FIG. 1, after the transparent resin precursor is filled, a cover film 5 is attached to the upper surface to protect the transmission lines 4 and 4.

The substrate 2 used in the present invention is not particularly limited as long as it is a material capable of forming a concave portion by a roll, but is preferably a thermoplastic resin, such as polyester, polyamide, polypropylene, or fluorine. A series resin, polyvinyl chloride, methacrylic resin, acetal resin and the like are used. More preferably, a methacrylic resin and an acetal resin are mentioned. The thickness of the substrate 2 can be variously selected depending on the application, but is preferably selected from the range of 100 μm to 1 cm.

A known embossing method can be adopted as a method for piercing the narrow grooves 3 used in the present invention. The embossing method is carried out by pressing an embossing roll having a convex portion corresponding to a desired concave portion onto the surface of the base material. It is common. As the embossing roll 6, as shown in FIG. 2, ridges 9, 9 forming narrow grooves 3, 3 on the outer peripheral surface of a rotating roll 8 rotated by a rotating shaft 7.
Are provided in the circumferential direction. The shape of the recess in the present invention is preferably close to the shape of the intended transmission line,
The shape of the transmission line is usually a column having a diameter of 10 to 1000 μm.

The transparent resin precursor used in the present invention contains a transparent resin precursor which is cured by heat or light such as ultraviolet (UV) light, and after curing, has a function of an optical waveguide. As the transparent resin precursor, a polymerizable monomer or a polymerizable oligomer is used, and heat, UV, or laser light such as an epoxy compound or a (meth) acrylate compound having 1 to 10 (meth) acryloyl groups in the molecule is used. Those which polymerize and cure by the above method can be suitably used. From the viewpoint of polymerization characteristics and optical characteristics, polyfunctional (meth) acrylate compounds are preferred. In addition, in order to cope with 1500 nm laser light, which is widely used in optical signal transmission by a laser, it is necessary to select a material that absorbs less at 1500 nm, such as a polysiloxane deuterium-substituted product, as a curable resin for the transmission path. preferable.

The transparent resin precursor preferably contains a polymerization initiator. As the polymerization initiator, a known combination of a radical generator and a sensitizer according to the polymerization method to be applied can be selected. As the photopolymerization initiator, a phosphine oxide compound can be suitably used, and specific examples thereof include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and benzophenone. As the thermal polymerization initiator, a peroxyester compound or the like can be preferably used, and specific examples thereof include benzoyl peroxide, diisopropyl peroxycarbonate and the like. These polymerization initiators may be used in an amount of 1% or less of the monomer. In addition, a solvent, a surfactant, and the like can be blended for improving coating properties and the like.

The refractive index of the cured transparent resin is 1.45 to 1.45.
The range of 1.65 can be selected and the range of the refractive index of the base resin can be selected within the range of 1.43 to 1.60, but the transmitted light is totally reflected at the boundary between the transmission path and the base. The condition to be satisfied is that the refractive index of the transmission path (core) is higher than that of the base material (cladding). For this purpose, the refractive index of the base resin is 1.43.
Will be selected from the range of ~ 1.55, preferably
It is set to 1.50 or less, and the transparent resin is selected in the range of 1.55 to 1.65, and most preferably 1.60 or more. In a waveguide having a diameter of 10 μm, the difference between the refractive index of the transmission path and the substrate is preferably experimentally 0.004 or more. Is increased, the possibility of occurrence of leakage light increases. Therefore, it is more preferably 0.01 or more. The absorptance of the light to be transmitted is -20 dB because the signal intensity incident at the input end of the light is -20 dB or less if the intensity receivable at the output end is less than -20 dB.
Since the signal attenuation must be less than / 100 m, the light absorption is preferably less than 3.5% / m.

The method of manufacturing the optical waveguide 1 of the present invention will be described in more detail with reference to FIG. 3. The elongated substrate 2 wound in a roll is embossed by a roll 6 to form narrow grooves 3. Is done. The roll 6 is desirably heated,
It is pressed by heating to 0 to 250C, preferably 60C to 200C. The base material 2 on which the narrow grooves 3 are formed is fed to the transparent resin precursor filling mechanism 10 to fill the narrow grooves 3 with the transparent resin precursor. In the figure, a roll coater method is used, and the roll 11 is filled. The filling means is not particularly limited, and a coating method such as a roll method, a bar coating method, a doctor blade method, or the like for applying to a substrate having a concave portion can be used. Alternatively, nozzles may be provided at intervals corresponding to the narrow grooves 3, 3, and the transparent resin precursor may be discharged in a thread form from the nozzles to fill the narrow grooves 3, 3.

When using the coating method, after coating, an operation for removing the precursor adhering to portions other than the narrow grooves 3 is performed. As the removing means, a blade method, a pressing method for removing the transparent resin precursor attached to the application surface other than the concave portion by pressing the cover film, or the like can be used.
In the figure, the cover film 5
Are superposed and pressed by the pressure squeezing rolls 13, 13 to attach the cover film 5 and squeeze out and remove excess precursor. Here, when the subsequent curing step is performed by using light such as UV light, the cover film 5 is preferably one having a high light transmittance, and particularly preferably the same material as the base material. Specifically, polyester, polyamide, polycarbonate, polymethacrylic resin, polypropylene, fluorine resin, polyvinyl chloride, and the like can be used. The pressing conditions are not particularly limited as long as the transparent resin precursor can be completely removed.

The substrate 2 from which the excess precursor has been removed is fed to a curing device 14, where the transparent resin precursor is cured. As the curing method, an ordinary method using light and / or heat can be employed, but a high-output exposure apparatus in the UV and visible light regions is preferable. Since the optical waveguide of the present invention is required to have a bending strength or the like depending on the application, it is preferable to laminate the reinforcing material layer 15 after the curing step. Further, it is desirable to further cover the outer periphery with protective films 16 in order to impart strength as an optical signal transmission path. Protective film 16
Can be the same thermoplastic resin as the reinforcing material 15.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to the following embodiments unless it exceeds the gist of the present invention. In the device shown in FIG.
A methacrylic resin (refractive index = 1.48, t
= 0.8 mm), the surface of the embossing roller 6 was shaped as shown in FIG. 2, heated to a temperature of 145 ° C., and pressure =
The grooves 3 were formed in the base sheet 2 by applying a pressure of 1.5 kg / cm. The substrate sheet 2 in which the grooves are formed is made of a monomer composition for a transparent resin (p-bis (β-methacryloyloxyethylthio) as a monomer in which a photopolymerization initiator of a resin for forming an optical waveguide by a polyurethane application roller 10 is blended. ) Xylene, refractive index 1.60), and cover film 5 (methacrylic resin, refractive index = 1.48, t =
0.5 mm), and the cover film was pressed with a squeeze roller 13 (made of stainless steel, pressure = 2 kg / cm), and at the same time, excess monomer composition was squeezed out. The sheet having passed through the squeezing roller 13 was introduced into a curing chamber 14 and cured by an ultraviolet lamp (2 kilowatts × 2). In the case of this embodiment, the sheet conveying speed is 200 m
m / sec to 300 mm / sec, but this speed was determined by the ultraviolet irradiation energy required for curing. After applying the protective film, if post-curing was advanced in the wound state, it was 10 times or more. I can give it. This condition can be selected according to the characteristics of the curable resin used as the optical waveguide.

The optical waveguide manufactured as described above can be used by cutting it to a desired length, polishing both end faces, and connecting with another optical fiber for signal transmission using a matching oil. The optical transmission capacity of the optical waveguide manufactured above in a use state is as follows with respect to a 780 nm laser beam through a 1 m transmission line.
It was 3 db / m. The value measured at 2 m is -45.
db, the attenuation rate of the optical waveguide is -1.5 db
/ M. From this result, when the transmission line manufactured as described above is used as an indoor optical signal transmission line, transmission of 5 to 10 m is possible.

[Brief description of the drawings]

1A and 1B are diagrams showing an embodiment of the optical waveguide of the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a side view.

FIG. 2 is a view showing an embossing roll, (A) is a side view,
(B) is a partially enlarged view of the roll surface.

FIG. 3 is an explanatory view showing a production example of the optical waveguide of the present invention.

[Explanation of symbols]

 1: optical waveguide 2: base material 3: narrow groove 4: transmission line 5: cover film 6: roll 10: transparent resin precursor filling mechanism 14: curing device 15: reinforcing material 16: protective film

Claims (10)

[Claims] A narrow groove extending in the longitudinal direction is formed in a long base material made of a thermoplastic resin by a rotating roll, and the narrow groove is filled with a transparent resin precursor forming a transmission path and cured. An optical waveguide, comprising: 2. The optical waveguide according to claim 1, wherein a cover film is attached to the narrow groove filled with the transparent resin precursor. 3. The optical waveguide according to claim 1, wherein the refractive index of the transparent resin forming the transmission path is greater than the refractive index of the substrate by 0.004 or more. 4. The base material is made of a thermoplastic resin, and
The optical waveguide according to any one of claims 1 to 3, wherein the transparent resin precursor comprises a polyfunctional methacrylate compound. 5. A method for manufacturing an optical waveguide, comprising the following steps (a) to (c). (A) forming a narrow groove extending in the longitudinal direction using a roll on a long base material; (b) filling a transparent resin precursor into the narrow groove; and (c) curing the transparent resin precursor. 6. The method of manufacturing an optical waveguide according to claim 5, further comprising a step of removing excess transparent resin precursor after filling the narrow groove with transparent resin. 7. The optical waveguide according to claim 5, further comprising a step of filling the narrow groove with a transparent resin, removing an excess of the transparent resin precursor if necessary, and then attaching a cover film to the upper surface thereof. Production method. 8. The method for manufacturing an optical waveguide according to claim 5, wherein the cover film is the same resin film as the base material. 9. The method of manufacturing an optical waveguide according to claim 5, wherein the refractive index of the transparent resin forming the transmission path is greater than the refractive index of the base material by 0.004 or more. 10. The method for producing an optical waveguide according to claim 5, wherein the base material is made of a thermoplastic resin, and the transparent resin precursor is made of a polyfunctional methacrylate compound.