JP2010122399A - Optical waveguide and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide that has a multi-layered structure in which a plurality of core layers are laminated with a cladding layer as an intermediate layer that enables the optical wiring of complicated design, and enables the higher speed and higher volume transmission of information signals. <P>SOLUTION: The optical waveguide is characterized in that a plurality of core layers 11 having cladding parts 11A and cores 11B are laminated with the cladding layer 10 as the intermediate layer wherein the core layers 11 and the cladding layer 10 contain resin components, the cores 11B have refractive indices relatively higher than those of the cladding parts 11A and the cladding layer 10, and the cladding layer 10 contains an ultraviolet ray adsorbing component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical waveguide and a manufacturing method thereof, and more particularly to an optical waveguide having a multilayer structure and a manufacturing method thereof.

  In electronic devices, there is an increasing demand for high-speed and high-capacity transmission of information signals between electronic components. In recent years, in order to cope with such high-speed and high-capacity transmission of information signals, it has been studied to connect electronic components with optical signals. In order to connect the electronic components with an optical signal, it has been studied to connect the electronic components with an optical waveguide.

As a method for manufacturing such an optical waveguide, for example, in Japanese Unexamined Patent Application Publication No. 2008-122898 (Patent Document 1), a first step of forming a first cladding layer on a substrate, and the first cladding A second step of laminating a core layer on the layer; a third step of exposing and developing the core layer to form a core pattern of an optical waveguide; and laminating a resin film for forming a second clad layer. Is disclosed. The method includes a fourth step of embedding in a second clad layer forming resin, and a fifth step of curing the clad layer forming resin to form a second clad layer. However, in the conventional method for manufacturing an optical waveguide as described in Patent Document 1, since the core is formed using photolithography, there is a problem that an etching process is necessary and the process is complicated. It was. Further, in such a conventional optical waveguide manufacturing method, after forming the core, the second cladding layer is laminated and the core is embedded in the second cladding layer, so that the core is formed on the surface of the second cladding layer. The uneven shape derived from the shape was generated, and it was difficult to smooth the surface. As described above, in the conventional method of manufacturing an optical waveguide, it is necessary not only to form a core using photolithography, but also to dispose a core and a clad layer on the second clad layer to form a multilayer structure. In order to manufacture the optical waveguide, it is necessary to smooth the surface of the second cladding layer, and the process is complicated.
JP 2008-122898 A

  The present invention has been made in view of the above-described problems of the prior art, and has a multilayer structure in which a plurality of core layers are laminated with a clad layer as an intermediate layer, enabling optical wiring with a complicated design, and information Providing optical waveguides that enable high-speed and high-capacity transmission of signals, and complex optical waveguides with a multilayer structure in which a plurality of core layers are stacked with a cladding layer as an intermediate layer in a simple process An object of the present invention is to provide a method of manufacturing an optical waveguide that can be efficiently manufactured.

  As a result of intensive studies to achieve the above object, the present inventors have first made a step (A) of forming a clad layer containing an ultraviolet absorbing component on the core layer, and a core precursor layer on the clad layer. And irradiating the core precursor layer with ultraviolet light through a photomask to form a cladding portion and a core portion in an ultraviolet light irradiation region and a non-irradiation region, respectively, thereby forming a cladding portion and a core portion. Since the cladding layer formed in the step (A) becomes a layer that absorbs ultraviolet light by the method of manufacturing an optical waveguide that performs the step (B) of forming the core layer having the core layer, the core in the step (B) When irradiating the precursor layer with ultraviolet light, the core layer (already formed core layer) laminated on the other surface of the cladding layer on which the core precursor layer is formed is irradiated with ultraviolet light. Formed on the core layer as it has no effect A new core layer can be formed on the clad layer using ultraviolet light, and a multilayer optical waveguide having a polymer core layer and a clad layer can be manufactured. I found. In addition, in the conventional method for manufacturing an optical waveguide, a plurality of optical waveguide structures are obtained while adopting a step of forming a core layer by irradiating ultraviolet light as a step of forming a core layer containing a resin component. There has not yet been found a method by which the core layer can be formed as a structure (multilayer structure) in which the core layer is laminated with the clad layer as an intermediate layer. And by the method of performing such steps (A) and (B), an optical waveguide having a complicated design in which a plurality of core layers are laminated with a cladding layer as an intermediate layer can be easily and efficiently manufactured. Has found that the resulting multi-layered optical waveguide can achieve high-speed and high-capacity transmission of information signals, and has completed the present invention.

  That is, the optical waveguide of the present invention is a layer in which a plurality of core layers having a clad part and a core part are laminated with the clad layer as an intermediate layer, and the core layer and the clad layer each contain a resin component. And the core portion has a refractive index relatively higher than that of the cladding portion and the cladding layer, and the cladding layer contains an ultraviolet absorbing component.

  The ultraviolet absorbing component according to the present invention includes a first photoacid generator having an absorption maximum wavelength in the ultraviolet region and releasing an acid upon irradiation with ultraviolet light, and a component derived from the first photoacid generator. It is preferably at least one component selected from the group consisting of

In the optical waveguide of the present invention, the absorption maximum wavelength of the first photoacid generator is preferably 300 to 400 nm. The first photoacid generator is at least one photoacid generator selected from the group consisting of aluminates, antimonates, borates, gallates, carboranes, and halocarboranes. It is preferable that Further, the first photoacid generator may be represented by the formula: -S (Ph) ₂ , -S ⁺ (Ph) ₃ , -I (Ph) _2, and -I ⁺ (Ph) ₃ [wherein Ph Represents a phenyl group. It is preferable that it consists of a compound which has at least 1 structure among the structures represented by this.

  In the optical waveguide of the present invention, it is preferable that the cladding layer contains a norbornene-based polymer.

  Furthermore, in the optical waveguide of the present invention, the core portion contains a norbornene polymer having a refractive index relatively higher than the resin component in the cladding layer, and the cladding portion is contained in the core portion. It is preferable to contain a norbornene polymer having a refractive index relatively lower than that of the norbornene polymer.

Moreover, the manufacturing method of the optical waveguide of this invention is the following process (A) and (B):
[Step (A)] A step of forming a clad layer containing an ultraviolet absorbing component on the core layer;
[Step (B)] A core precursor layer is formed on the clad layer, and the core precursor layer is irradiated with ultraviolet light through a photomask, and the ultraviolet light irradiated region and the non-irradiated region are respectively coated with the cladding portion and Forming a core layer having a clad portion and a core portion by forming a core portion;
And obtaining an optical waveguide in which a plurality of core layers are laminated with a clad layer as an intermediate layer.

  In the method for producing an optical waveguide of the present invention, a core precursor layer is formed on a base material or a clad layer formed on the base material before performing the steps (A) and (B). The core precursor layer is irradiated with ultraviolet light through a photomask, and a clad part and a core part are formed in an ultraviolet light irradiated area and a non-irradiated area, respectively. It is preferable to form a layer.

  In the method for producing an optical waveguide of the present invention, the step (A) is preferably a step of forming a clad layer by applying a clad layer forming varnish containing an ultraviolet absorber on the core layer, It is more preferable that the clad layer is formed by applying a clad layer forming varnish containing an ultraviolet absorber on the core layer and then irradiating with ultraviolet light.

  In the method for producing an optical waveguide of the present invention, the step of forming the core precursor layer is preferably a step of forming a core precursor layer by applying a core layer forming varnish on the cladding layer.

  In the method for manufacturing an optical waveguide of the present invention, the varnish for forming a cladding layer has a first photoacid generator that has an absorption maximum wavelength in an ultraviolet region and releases an acid upon irradiation with ultraviolet light, It is preferable to contain a polymer.

In the optical waveguide manufacturing method of the present invention, it is preferable that the absorption maximum wavelength of the first photoacid generator is 300 to 400 nm. The first photoacid generator is at least one photoacid generator selected from the group consisting of aluminates, antimonates, borates, gallates, carboranes, and halocarboranes. It is preferable that Further, the first photoacid generator may be represented by the formula: -S (Ph) ₂ , -S ⁺ (Ph) ₃ , -I (Ph) _2, and -I ⁺ (Ph) ₃ [wherein Ph Represents a phenyl group. It is preferable that it consists of a compound which has at least 1 structure among the structures represented by this.

  In the method for producing an optical waveguide of the present invention, the first polymer is preferably a norbornene polymer having a side chain containing a polymerizable group, and the norbornene polymer having a side chain containing an epoxy group It is more preferable that

  In the method for producing an optical waveguide of the present invention, the varnish for forming a core layer has a second photoacid generator that has an absorption maximum wavelength in an ultraviolet region and releases an acid upon irradiation with ultraviolet light, and the second photoacid generator. The photoacid generator preferably contains a second polymer having a side chain containing a leaving group that is released by the acid released.

  In the method for producing an optical waveguide of the present invention, the second polymer is preferably a norbornene-based polymer having a side chain containing the leaving group, and the leaving group has the formula: − A group containing at least one of the structures represented by O-, -Si- and -O-Si- is preferable.

  According to the present invention, an optical fiber having a multilayer structure in which a plurality of core layers are laminated with a cladding layer as an intermediate layer, enabling optical wiring with a complicated design, and enabling high-speed and high-capacity transmission of information signals. Optical waveguide manufacturing method capable of providing a waveguide, and capable of efficiently manufacturing an optical waveguide with a complex design having a multilayer structure in which a plurality of core layers are laminated with a cladding layer as an intermediate layer in a simple process Can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

  FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the optical waveguide of the present invention. The optical waveguide 1 shown in FIG. 1 includes a clad layer 10 and a core layer 11 having a clad portion 11A and a core portion (waveguide channel) 11B, and the two core layers 11 are laminated via the clad layer 10. Has a structure. With such a configuration, the core portion 11B functions as a light guide path.

  The clad layer 10 is a layer containing a resin component.

  The resin component in the clad layer 10 is not particularly limited, and a known polymer that can be used for forming the clad layer in the optical waveguide can be appropriately used. For example, a cyclic olefin-based resin can be used. , Polymers such as acrylic resins, methacrylic resins, polycarbonates, polystyrenes, epoxy resins, polyamides, polyimides, polybenzoxazoles, polymer alloys combining one or more of these polymers, polymer blends (mixtures), A copolymer, a crosslinked body, etc. are mentioned as a suitable thing. In the optical waveguide including the cladding layer 10 containing such a resin component, the refractive index of the cladding layer 10 is lower than the refractive index of the core portion 11B in order to make the core portion 11B sufficiently function as a light guide. There is a need to. Therefore, as the resin component in the cladding layer 10, it is preferable to select and use a resin component having a lower refractive index than the material forming the core layer 11B.

  As a resin component in such a clad layer 10, from the viewpoint of flexibility, heat resistance, and moisture resistance, the following general formula (1) in the main chain:

It is preferable to contain the norbornene-type polymer which has a structural unit represented by these. The resin component in the clad layer 10 is a resin formed from a first polymer in a clad forming varnish described later (for example, the first polymer itself, a reaction product between the first polymers, One polymer and a resin formed by reacting a monomer, a cross-linking agent, etc. in the clad forming varnish are preferable.

  Furthermore, the content ratio of the resin component in the cladding layer 10 is preferably 80% by mass to 99% by mass with respect to the total mass of the cladding layer. If such a ratio is less than the lower limit, the properties of the cladding layer derived from the properties of the resin component tend to be reduced. For example, when a norbornene-based polymer is used as the resin component, it is derived from the properties of the norbornene-based polymer. On the other hand, if the upper limit is exceeded, UV absorbers and photoacid generator components cannot be sufficiently added, so that the UV absorption performance and heat resistance of the cladding layer are reduced. It tends to decrease.

  The cladding layer 10 is a layer containing an ultraviolet absorbing component. Such an ultraviolet absorbing component is not particularly limited as long as it can absorb ultraviolet rays. For example, paramethoxycinnamic acid 2-ethylhexyl, paradimethylaminobenzoic acid 2-ethylhexyl, oxybenzone, 4-tert-butyl-4 -A UV absorber such as methoxy-benzoylmethane, a first photoacid generator having an absorption maximum wavelength in the ultraviolet region and releasing an acid upon irradiation with ultraviolet light, and a component derived from the first photoacid generator It may be at least one component selected from the group consisting of

  As such an ultraviolet-absorbing component, from the viewpoint of the production efficiency of the cladding layer, etc., the first photoacid generator that has an absorption maximum wavelength in the ultraviolet region and releases an acid upon irradiation with ultraviolet light, At least one component selected from the group consisting of components derived from a photoacid generator is preferred. As used herein, the “component derived from the first photoacid generator” is a component obtained by decomposing the first photoacid generator by heat or light irradiation or reacting with other components. The component having an absorption maximum wavelength in the ultraviolet region.

  Moreover, as such a 1st photo-acid generator, what has an absorption maximum wavelength in 300-400 nm is preferable. If the absorption maximum wavelength is less than the lower limit, it is less than the lower limit of the ultraviolet wavelength irradiated from a normal high-pressure mercury lamp or metal halide lamp, so that the ultraviolet absorption ability is not substantially exhibited, and the cladding layer exhibits ultraviolet absorption performance. Tend to be difficult. On the other hand, if the upper limit is exceeded, the cladding layer absorbs light in the visible light region, so in the process of laminating by precisely controlling the position of the optical waveguide left and right and up and down, the lower optical waveguide shape is clad from the top It becomes difficult to identify through the layers, and the manufacturing process tends to be complicated. In addition, as such a first photoacid generator, ultraviolet light that could not be absorbed is scattered by the cladding layer so that the waveguide pattern of the core layer is not affected by the ultraviolet light more efficiently. From the viewpoint of being possible, it is more preferable to color by irradiation with ultraviolet light.

  The first photoacid generator is not particularly limited as long as it has an absorption maximum wavelength in the ultraviolet region and can release an acid by irradiation with ultraviolet light. From the viewpoint that it is possible to achieve both high stability and solubility in a polymer material, aluminates, antimonates, borates, gallates, carboranes, and halocarboranes are preferable. , Hexafluoroantimonate, tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) gallate and the like. Moreover, as such a first photoacid generator, a commercially available photoacid generator may be used. As a commercial item of such a photoacid generator, for example, “RHODORSIL (registered trademark) PHOTOINITIATOR 2074 (CAS No. 178233-72-2)” available from Rhodia USA, available from Toyo Ink Manufacturing Co., Ltd. Possible "TAG-372R ((dimethyl (2- (2-naphthyl) -2-oxoethyl) sulfonium tetrakis (pentafluorophenyl) borate: CAS No. 193957-54-9)), from Midori Chemical Co., Ltd. Available "MPI-103 (CAS No. 87709-41-9)", "TAG-371 (CAS No. 193957-53-8)" available from Toyo Ink Manufacturing Co., Ltd., Toyo Gosei Kogyo Co., Ltd. "TTBPS-TPFPB (Tris (4-te rt-butylphenyl) sulfonium tetrakis (pentapentafluorophenyl) borate) ". When RHODORSIL PHOTOINITIATOR 2074 is used as the first photoacid generator, it is preferable to use a high-pressure mercury lamp or a metal halide lamp as the ultraviolet light irradiation means. As a result, ultraviolet light with sufficient energy of less than 300 nm can be supplied, and RHODORSIL PHOTOINITIATOR 2074 can be efficiently decomposed to generate an acid.

In addition, as such a first photoacid generator, a component derived from the first photoacid generator (a component obtained by decomposing the first photoacid generator, the first photoacid generator). From the standpoint that the function that the generator generates by reacting with other substances) can absorb UV light sufficiently, it absorbs UV light and converts it into infrared light or visible light. It is preferable to include a structural portion capable of releasing sucrose. Examples of such a structural moiety include a structure represented by the formula: -S (Ph) ₂ ; -S ⁺ (Ph) ₃ ; -I (Ph) ₂ ; -I ⁺ (Ph) ₃ ; Among them, Ph represents a phenyl group. ] Etc. are mentioned.

  Furthermore, the content ratio of the ultraviolet absorbing component in the cladding layer is preferably 1% by mass to 10% by mass with respect to the total mass of the cladding layer 10. If such a ratio is less than the lower limit, it tends to be difficult to provide sufficient ultraviolet absorption performance. On the other hand, if the upper limit is exceeded, the refractive index of the cladding layer itself increases, and the refractive index difference from the core layer. Therefore, the optical confinement in the optical waveguide tends to be insufficient.

  Further, such a clad layer 10 is preferably a layer obtained by a clad layer forming varnish, which will be described later, and obtained by carrying out the step (A) employed in the optical waveguide manufacturing method of the present invention, which will be described later. More preferably, it is a layer to be formed.

  The average thickness Z of the cladding layer 10 is not particularly limited, but is preferably 1 to 200 μm, more preferably 5 to 100 μm, and still more preferably 10 to 60 μm. Further, the average thickness Z of the clad layer 10 is preferably 0.1 to 1.5 times, and preferably 0.3 to 1.25 times the average thickness X of the core layer 11. More preferred. By making the average thickness Z of the clad layer 10 fall within the above range, the optical waveguide 1 is prevented from being unnecessarily enlarged (thickened), and the function as the clad layer 10 is more fully exhibited. Tend to be.

  The core layer 11 is a layer containing a resin component. The resin component for forming such a core layer is not particularly limited, and a known polymer that can be used for forming the core layer of the optical waveguide can be appropriately used. For example, a cyclic olefin resin, an acrylic resin Polymers, methacrylic resins, polycarbonates, polystyrenes, epoxy resins, polyamides, polyimides, polybenzoxazoles, etc., and polymer alloys, polymer blends (mixtures), co-polymers combining one or more of these polymers A combination, a crosslinked body, etc. are mentioned as a suitable thing. Note that the resin component in the core layer 11 and the resin component in the clad layer 10 may be the same, but from the viewpoint that a difference in refractive index can be more easily generated. It is preferable that they are of different types (including those having the same main chain and different types of side chains).

  The resin component in the core layer 11 is represented by the above general formula (1) in the main chain from the viewpoint of excellent light transmittance in a wavelength region near 850 nm and having both heat resistance and flexibility. It is preferable to contain a norbornene-based polymer having a structural unit.

  Further, the resin component in the core portion 11B of the core layer 11 has a refractive index relatively higher than that of the resin component in the cladding layer 10 from the viewpoint of causing the core portion 11B to function more efficiently as a light guide. It is preferable to use a norbornene-based polymer having Further, as a resin component in the clad part 11A, a norbornene polymer having a refractive index relatively lower than that of the norbornene polymer in the core part 11B is used from the viewpoint of allowing the core part 11B to function more efficiently as a light guide. It is preferable to contain. The difference in the refractive index of the norbornene-based polymer at each site may change the type of repeating unit in the polymer, or change the content ratio of the repeating unit even in a polymer containing the same repeating unit. It is possible to adjust by such as.

  Further, the resin component in the core layer 11 is a resin formed from a second polymer in the core-forming varnish described later (for example, the second polymer itself, a reaction product between the second polymers, It is preferable that the second polymer and a resin or the like formed by the reaction of the monomer in the core-forming varnish, the crosslinking agent, or the like. Moreover, it is preferable that the core layer 11 is a layer obtained by the core formation varnish mentioned later, and is a layer obtained by implementing the process (B) employ | adopted in the manufacturing method of the optical waveguide of this invention mentioned later. It is more preferable.

  The average thickness X of the core layer 11 can be appropriately changed depending on its use and is not particularly limited, but is preferably 1 to 200 μm, more preferably 5 to 100 μm. More preferably, it is ˜60 μm. Further, the cross-sectional shape of the core portion 11B is not particularly limited, but is preferably substantially square or substantially rectangular (substantially rectangular). The width Y of the core portion 11B can be appropriately changed depending on its application and is not particularly limited, but is preferably 1 to 200 μm, more preferably 5 to 100 μm. More preferably, it is 10-60 micrometers. Further, the core portion 11B may be linear or may be curved or branched in the middle, and the shape can be appropriately changed according to the intended use.

In addition, the core part 11 </ b> B in the core layer 11 has a relatively higher refractive index than the cladding part 11 </ b> A and the cladding layer 10. The refractive index difference between the core part 11B and the clad part 11A is not particularly limited, but when the clad part 11A contains a resin component, it is 0.3 to 5.5%. Preferably, it is 0.8 to 2.2%. If the refractive index difference is less than the lower limit, the effect of transmitting light through the core portion tends to be reduced. The “refractive index difference” mentioned here is expressed by the following formula when the refractive index of the clad portion 11A is n _A and the refractive index of the core portion 11B is n _B :
Refractive index difference (%) = {(n _B / n _A ) −1} × 100
The value obtained by calculating is adopted.

  Further, the refractive index difference between the core portion 11B and the clad layer 10 is not particularly limited as long as the refractive index of the clad layer 10 is lower than the refractive index of the core portion 11B, but the clad layer 10 contains a resin component. When it is a layer to contain, it is preferable that it is 0.2 to 20%, and it is more preferable that it is 0.5 to 10%. If the refractive index difference is less than the lower limit, the effect of transmitting light through the core portion tends to be reduced.

  In the optical waveguide 1 of the present embodiment, the refractive index of the core portion 11B is relatively higher than the refractive index of air. Thus, when the core layer 11 is a layer in contact with air, the core portion 11B can function more efficiently as a light guide by making the refractive index of the core portion 11B relatively higher than the refractive index of air. Is possible.

  In addition, when the core portion 11B is in contact with air, the refractive index of the core portion 11B is relatively higher than the refractive index of air, and the difference in refractive index between the core portion 11B and air is 50-60%. It is preferable. When the difference in refractive index is less than the lower limit, the performance of propagating the light of the core 11B tends to decrease. On the other hand, when the upper limit is exceeded, light scattering increases and the light propagation loss tends to increase. .

  Furthermore, the preferred use of such an optical waveguide 1 is different depending on the optical characteristics and the like of the material of the core portion 11A, and therefore cannot be generally stated. For example, light having a wavelength region of about 600 to 1550 nm is used. It is preferably used in the used data communication. In use, the optical waveguide 1 may be installed on various substrates. Further, such an optical waveguide 1 may be used by appropriately providing a conductor layer or the like according to the purpose of use or the like.

  Next, with respect to a preferred embodiment of the optical waveguide manufacturing method of the present invention that can be suitably employed as a method for manufacturing the optical waveguide 1 shown in FIG. 1, FIGS. The description will be given with reference.

In a preferred embodiment of the method for producing an optical waveguide of the present invention, after preparing a core layer laminated base material as shown in FIG. 2 in which a core layer is formed on the base material, the following step (A ) And (B):
[Step (A)] A step of forming a clad layer containing an ultraviolet absorbing component on the core layer;
[Step (B)] A core precursor layer is formed on the clad layer, the core precursor layer is irradiated with ultraviolet light through a photomask, and the clad portions are respectively applied to the ultraviolet light irradiation region and the non-irradiation region. Forming a core layer having a clad portion and a core portion by forming a core portion and a core portion;
In order, and manufacturing the optical waveguide 1 having a three-layer structure as shown in FIG.

  First, the process of forming a clad layer on the core layer 11 of the core layer laminated substrate will be described. Such a process is a process (process (A)) of forming the clad layer 10 containing an ultraviolet absorbing component on the core layer 11. In addition, the core layer laminated base material shown in FIG. 2 is obtained by laminating the core layer 11 on the base material 20, and the manufacturing method thereof will be described later.

  In the step of forming such a cladding layer (step (A)), it is preferable to form the cladding layer using a cladding layer forming varnish. As such a varnish for forming a clad layer, one containing the ultraviolet absorber and the first polymer is preferable.

  As such an ultraviolet absorber, after the clad layer is formed, components derived from the ultraviolet absorber (components obtained by decomposing the ultraviolet absorber, obtained by reacting the ultraviolet absorber with other substances) The component and the ultraviolet absorber itself are not particularly limited as long as they become the ultraviolet absorbing component present in the clad layer 10, and examples thereof include 2 ethylhexyl paramethoxycinnamate, paradimethylaminobenzoic acid 2 Examples include UV absorbers such as ethylhexyl, oxybenzone, 4-tert-butyl-4-methoxy-benzoylmethane, and a first photoacid generator that has an absorption maximum wavelength in the ultraviolet region and releases acid upon irradiation with ultraviolet light. It is done. Among such ultraviolet absorbers, from the viewpoint that a cladding layer can be formed more efficiently, it is the first photoacid generator that has an absorption maximum wavelength in the ultraviolet region and releases an acid upon irradiation with ultraviolet light. preferable. In addition, such a 1st photoacid generator is the same as the 1st photoacid generator suitable as an above-mentioned ultraviolet absorption component. Moreover, the suitable thing of a 1st photoacid generator is the same as the suitable thing of a 1st photoacid generator suitable as an ultraviolet-ray absorption component.

  Examples of the first polymer include cyclic olefin resins (including norbornene resins and benzocyclobutene resins), acrylic resins, methacrylic resins, polycarbonates, polystyrenes, epoxy resins, polyamides, polyimides, Polybenzoxazole can be used, and one or more of these can be used in combination (polymer alloy, polymer blend (mixture), copolymer, etc.). Among these, what mainly contains the norbornene-type resin (norbornene-type polymer) which has a structure represented by the said Formula (1) in a principal chain is preferable. Such a norbornene-based polymer is not particularly limited, and a known norbornene-based polymer that can be used when forming the cladding layer can be appropriately used.

  Since such a norbornene-based polymer tends to have an excellent balance between heat resistance and adhesion, when this is used as a constituent material of the cladding layer 10, it is heated when a conductor layer or the like is formed in an optical waveguide. Even so, the cladding layer 10 tends to be sufficiently prevented from being softened and deformed. Further, since such norbornene-based polymer has high hydrophobicity, a dimensional change due to water absorption of the clad layer 10 tends not to occur. Further, such a norbornene-based polymer is preferable because a norbornene-based monomer as a raw material thereof is relatively inexpensive and easily available.

  In addition, by including a norbornene polymer in the first polymer in the clad layer forming varnish, it is excellent in resistance to deformation such as bending, and even when repeatedly bent and deformed, the interlayer between the clad layer 10 and the core layer 11 Peeling is unlikely to occur, and the occurrence of microcracks in the cladding layer 10 tends to be sufficiently prevented. Further, when a norbornene-based polymer is also used for the core layer 11, the adhesion between the clad layer 10 and the core layer 11 becomes higher, and delamination between the clad layer 10 and the core layer 11 is further improved. It tends to be sufficiently prevented. By using the norbornene-based polymer in this way, it becomes possible to obtain an optical waveguide with excellent durability while maintaining the optical transmission performance of the optical waveguide sufficiently.

  Examples of such norbornene-based polymers include (1) addition (co) polymers of norbornene monomers obtained by addition (co) polymerization of norbornene monomers, and (2) norbornene monomers and ethylene or α-olefins. (3) addition polymers such as addition copolymers with norbornene-type monomers and non-conjugated dienes, and other monomers as required, (4) ring opening of norbornene-type monomers ( A (co) polymer, and a resin obtained by hydrogenating the (co) polymer if necessary, (5) a ring-opening copolymer of a norbornene-type monomer and ethylene or α-olefins, and ( (Co) polymer hydrogenated resin, (6) ring-opening copolymer of norbornene type monomer and non-conjugated diene or other monomer, and (co) polymerization if necessary And a ring-opening polymer such as a polymer obtained by hydrogenating the body. Examples of these polymers include random copolymers, block copolymers, and alternating copolymers. Among such norbornene-based polymers, addition (co) polymers are more preferable from the viewpoint of sufficient heat resistance and flexibility.

  Further, such a norbornene-based polymer may be selected appropriately from known norbornene-based monomers according to its design, and used in ring-opening metathesis polymerization (ROMP), a combination of ROMP and a hydrogenation reaction, radical or Manufactured using a known polymerization method such as polymerization using a cation, polymerization using a cationic palladium polymerization initiator, or polymerization using other polymerization initiators (for example, polymerization initiators of nickel and other transition metals). can do.

  Examples of such norbornene-based polymers include copolymers of butylbornene and methyl glycidyl ether norbornene, copolymers of hexyl norbornene and methyl glycidyl ether norbornene, copolymers of decyl norbornene and methyl glycidyl ether norbornene, butylbornene and acrylic acid 2 -Copolymer of (5-norbornenyl) methyl, copolymer of hexylnorbornene and 2- (5-norbornenyl) methyl acrylate, copolymer of decylnorbornene and 2- (5-norbornenyl) methyl acrylate, butylbornene and norbornenyl Copolymer with ethyltrimethoxysilane, hexylnorbornene and norbornenylethyltrimethoxysilane copolymer, decylnorbornene Copolymer of norbornenylethyltrimethoxysilane, copolymer of butylbornene and triethoxysilylnorbornene, copolymer of hexylnorbornene and triethoxysilylnorbornene, copolymer of decylnorbornene and triethoxysilylnorbornene, butylbornene and trimethoxysilylnorbornene A copolymer of hexyl norbornene and trimethoxysilyl norbornene, a copolymer of decyl norbornene and trimethoxysilyl norbornene, one of butylbornene, hexylnorbornene or decylnorbornene, 2- (5-norbornenyl) methyl acrylate, and norbornene Nylethyltrimethoxysilane, triethoxysilylnorbornene or trimethoxysilylnor A terpolymer with any of the runnes, butylbornene, hexylnorbornene or decylnorbornene with a terpolymer of 2- (5-norbornenyl) methyl acrylate and methylglycidyl ether norbornene, with either butylbornene, hexylnorbornene or decylnorbornene , Terpolymers of methyl glycidyl ether norbornene, norbornenyl ethyl trimethoxysilane, triethoxysilyl norbornene or trimethoxysilyl norbornene, copolymers of butylbornene and diphenylmethylnorbornene methoxysilane, hexyl norbornene and diphenylmethylnorbornene methoxysilane Copolymer of decylnorbornene and diphenylmethylnorbornene Examples thereof include a copolymer of lanthanum, a copolymer of butylbornene and phenylethylnorbornene, a copolymer of hexylnorbornene and phenylethylnorbornene, and a copolymer of decylnorbornene and phenylethylnorbornene.

  Further, as such a norbornene-based polymer, a norbornene repeating unit having a side chain containing a polymerizable group, a norbornene repeating unit having a side chain containing an aryl group, and a norbornene having an alkyl group in the side chain Those containing at least one of the repeating units of (alkylnorbornene) are preferable, and those containing at least one repeating unit of norbornene having a side chain containing a polymerizable group are more preferable.

  When the repeating unit of norbornene having a side chain containing such a polymerizable group is included, the norbornene polymers in the cladding layer 10 may be crosslinked directly or via a crosslinking agent with the polymerizable group, Depending on the type of polymer used in the core layer, the polymer used in the core layer and the norbornene-based polymer can be cross-linked, and the strength of the clad layer 10 itself and the adhesion between the clad layer 10 and the core layer are further improved. Can be achieved. As such a side chain polymerizable group, at least one of an epoxy group, a (meth) acryl group, and an alkoxysilyl group is preferable from the viewpoint of reactivity, and an epoxy group is preferable from the viewpoint of colorability. Particularly preferred. That is, it is particularly preferable to use a norbornene-based polymer having a side chain containing an epoxy group as the first polymer. In the norbornene-based polymer, the norbornene repeating unit having a polymerizable group in the side chain may contain only one type of repeating unit, or two or more types each having a different polysynthetic group. It may contain a repeating unit. Among them, the crosslinking density can be further improved, and the above effect becomes more remarkable. Therefore, the repeating unit contains two or more kinds of norbornene repeating units each having a different polymerizable group. It is preferable.

  In addition, when the norbornene-based polymer includes a norbornene repeating unit having a side chain containing an aryl group, the aryl group has extremely high hydrophobicity, and therefore tends to prevent a change in dimensions of the cladding layer 10 due to water absorption. is there. In addition, since the aryl group is excellent in fat solubility (lipophilicity), the affinity with the polymer used in the core layer can be improved, thereby preventing delamination between the clad layer 10 and the core layer. Thus, it becomes possible to obtain an optical waveguide with higher durability.

  Furthermore, when the norbornene-based polymer contains an alkylnorbornene repeating unit, the transmittance for light in the wavelength region of about 600 to 1550 nm (particularly in the wavelength region near 850 nm) tends to be excellent. The flexibility tends to be high, and the cladding layer 10 tends to be provided with high flexibility (flexibility). The alkyl group in the side chain in the repeating unit of such an alkylnorbornene may be either linear or branched, and may have a substituent. The alkyl group is not particularly limited, but is methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl. Group, octyl group, nonyl group, decyl group and the like. The substituent that the alkyl group may have is not particularly limited, and examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

  Further, the number of carbon atoms of the side chain alkyl group in the repeating unit of such an alkylnorbornene is not particularly limited, but is more preferably 1 to 20 (more preferably 3 to 12). If the number of carbon atoms is less than the lower limit, flexibility from the polymer tends to be impaired, and application to applications that require flexibility tends to be difficult. On the other hand, if the upper limit is exceeded, the heat resistance of the polymer Tend to decrease. By including such a repeating unit of alkyl norbornene, even when the repeating unit of norbornene having a side chain containing an aryl group having a relatively high refractive index is further included, an increase in the refractive index of the cladding layer is prevented. It becomes possible.

  Among such norbornene-based polymers, those containing a norbornene repeating unit having an alkyl group in the side chain (an alkylnorbornene repeating unit) and a norbornene repeating unit having a side chain containing a polymerizable group Among them, the following general formula (2) containing a repeating unit of alkylnorbornene and a repeating unit of norbornene having a side chain containing an epoxy group:

[Wherein, R represents an alkyl group, a represents an integer of 0 to 3, b represents an integer of 1 to 3, p and q may be the same or different, and each represents 20 or less. Indicates an integer. ]
A norbornene-based polymer having a structure represented by: In addition, the alkyl group represented by R in the said General formula (2) is the same as the alkyl group of the side chain in the repeating unit of the said alkyl norbornene.

  Among the norbornene-based polymers having the repeating unit represented by the general formula (2), compounds in which R is an alkyl group having 4 to 10 carbon atoms and a and b are each 1 (for example, butylbornene and methyl More preferred are copolymers of glycidyl ether norbornene, copolymers of hexyl norbornene and methyl glycidyl ether norbornene, and copolymers of decyl norbornene and methyl glycidyl ether norbornene.

  In the case where a norbornene polymer is mainly used as the first polymer, the content ratio of the norbornene polymer in the first polymer is preferably 80 to 100% by mass, and more preferably 95 to 100% by mass. preferable. When such a content ratio is less than the lower limit, the effect obtained by using the norbornene-based polymer tends to be insufficient.

  Moreover, in the said varnish for clad layer formation, you may further contain a monomer, a procatalyst, a sensitizer, and antioxidant other than the said ultraviolet absorber and said 1st polymer as needed.

  As such a monomer, a compound that forms a reaction product by reacting with the irradiation of ultraviolet light using the first polymer as a matrix is preferable. The reactant derived from such a monomer includes a polymer (polymer) formed by polymerizing the monomer in the first polymer (matrix), a crosslinked structure that crosslinks the first polymers, and the first polymer. And a branched structure (branched polymer or side chain) branched from the first polymer by polymerization.

  Moreover, it is preferable to use what contains a crosslinkable monomer as such a monomer. Thereby, in the clad layer 10, at least some of the norbornene-based polymers can be crosslinked through the crosslinkable monomer. In addition, depending on the type of polymer used for forming the cladding layer 10, the norbornene-based polymer in the cladding layer 10 and the polymer used for forming the core layer can be cross-linked. As such a crosslinking monomer, a known monomer can be appropriately used.

  Such a monomer is not particularly limited as long as it can be used for forming an optical waveguide. For example, a norbornene monomer, an acrylic acid (methacrylic acid) monomer, an epoxy monomer, and a styrene monomer Etc., and one or more of these can be used in combination. Among these, as the monomer, it is preferable to use a norbornene-based monomer from the viewpoint that an optical waveguide having excellent heat resistance and flexibility can be obtained. The “norbornene monomer” here refers to a monomer having at least one structure represented by the above formula (1) in the skeleton.

  Such a norbornene-based monomer may have a substituent bonded to the structure represented by the above formula (1). Such a substituent is not particularly limited, and examples thereof include a linear or branched alkyl group, a linear or branched alkenyl group, and a linear or branched alkynyl group. A linear or branched cycloalkyl group, a linear or branched cycloalkenyl group, a linear or branched aryl group, a linear or branched aralkyl group, Examples thereof include a linear or branched alkylidenyl group, a hydrocarbyl group, a halohydrocarbyl group, and a perhalohydrocarbyl group. Examples of such norbornene-based monomers include propyl norbornene and hexyl norbornene.

Further, such a norbornene-based monomer may be one in which a plurality of norbornene rings are bonded via an organic group. Examples of such an organic group is not particularly limited, for example, the following formula _{:-( CH 2) n - ;-( CH} 2) n -O- (CH 2) n -; - Ar-; or ;-( CH _{2) n -O-Si (X} ) 2 -O- (CH 2) n - [ wherein, n represents an integer of 1 to 10, Ar is an aromatic hydrocarbon which may have a substituent X represents an alkyl group which may have a substituent and an aromatic hydrocarbon which may have a substituent. ] Is represented. In addition, the several norbornene ring couple | bonded through such an organic group may have the said substituent, respectively. Examples of such norbornene-based monomers include bis-norbornene methoxydimethylsilane, bis-norbornene methoxydiethylsilane, and bis-norbornenemethoxydiphenylsilane.

  In addition, as such a monomer, the monomer described in the international publication 2005/052641 pamphlet can be used.

  The procatalyst is a substance that can initiate the reaction of the monomer (polymerization reaction, crosslinking reaction, etc.), and the substance whose activation temperature changes due to the action of a photoacid generator activated by irradiation with ultraviolet light. It is. Such a procatalyst (also referred to as a catalyst precursor) is not particularly limited as long as the activation temperature changes (increases or decreases) with irradiation with ultraviolet light, but is not limited with irradiation with ultraviolet light. More preferably, the activation temperature is lowered. With such a procatalyst, it is not necessary to perform heating that adds unnecessary heat to other layers during the preparation of the optical waveguide, and the characteristics (optical transmission performance) of the optical waveguide deteriorate due to the heat treatment during the preparation. It can be sufficiently prevented.

As such a procatalyst, those containing (mainly) at least one of the compounds represented by the following general formulas (Ia) and (Ib) are preferably used.
(E (R) ₃ ) ₂ Pd (Q) ₂ ... (Ia)
[(E (R) ₃ ) _a Pd (Q) (LB) _b ] _p [WCA] _r (Ib)
In the general formulas (Ia) and (Ib), E (R) ₃ represents a neutral electron donor ligand of Group 15, and E represents an element selected from Group 15 of the periodic table. R represents a hydrogen atom (or one of its isotopes) or a moiety containing a hydrocarbon group, and Q represents an anion coordination selected from the group consisting of carboxylate, thiocarboxylate and dithiocarboxylate Represents a child. In general formula (Ib), LB represents a Lewis base, WCA represents a weakly coordinating anion, a represents an integer of 1 to 3, b represents an integer of 0 to 2, and a and b And p and r represent numbers that balance the charge between the palladium cation and the weakly coordinated anion.

Typical procatalysts according to the general formula (Ia) include Pd (OAc) ₂ (P (i-Pr) ₃ ) ₂ , Pd (OAc) ₂ (P (Cy) ₃ ) ₂ , Pd (O ₂ CCMe ₃ ) ₂ (P (Cy) ₃ ) ₂ , Pd (OAc) ₂ (P (Cp) ₃ ) ₂ , Pd (O ₂ CCF ₃ ) ₂ (P (Cy) ₃ ) ₂ , Pd (O ₂ CC ₆ H ₅ ) ₃ (P (Cy) ₃ ) ₂ may be mentioned, but is not limited thereto. Here, Cp represents a cyclopentyl group, and Cy represents a cyclohexyl group.

Moreover, as a procatalyst represented by the said general formula (Ib), the compound whose p and r are either one of the integers of 1 and 2, respectively is preferable. A typical procatalyst according to the general formula (Ib) includes Pd (OAc) ₂ (P (Cy) ₃ ) ₂ . Here, Cy represents a cyclohexyl group, and Ac represents an acetyl group.

  The sensitizer increases the sensitivity of the photoacid generator to ultraviolet light, reduces the time and energy required for activation (reaction or decomposition), and emits ultraviolet light at a wavelength suitable for the activation. It has a function to change the wavelength of. Such a sensitizer is appropriately selected according to the sensitivity of the photoacid generator and the peak wavelength of absorption of the sensitizer, and is not particularly limited. For example, 9,10-dibutoxyanthracene (CAS No. 76275-14-4) anthracenes, xanthones, anthraquinones, phenanthrenes, chrysene, benzpyrenes, fluoranthenes, rubrenes, pyrenes, indanthrines, thioxanthene-9- Thioxanthen-9-ones. Specific examples of the sensitizer include 2-isopropyl-9H-thioxanthen-9-one, 4-isopropyl-9H-thioxanthen-9-one, 1-chloro-4-propoxythioxanthone, and phenothiazine. It is done. These sensitizers can be used alone or in combination of two or more. In addition, 9,10-dibutoxyanthracene (DBA) can be obtained from Kawasaki Kasei Kogyo Co., Ltd.

  Further, the antioxidant can improve the characteristics of the optical waveguide obtained by preventing the generation of free radicals and the natural oxidation of the polymer. As such an antioxidant, Ciba (R) IRGANOX (R) 1076 and Ciba IRGAFOS (R) 168 available from Ciba Specialty Chemicals are preferably used. In addition, as other antioxidants, for example, Ciba Irganox (registered trademark) 129, Ciba Irganox 1330, Ciba Irganox 1010, Ciba Cyanox (registered trademark) 1790, Ciba Irganox (registered trademark) 3114, Ciba Ix it can.

  In the clad layer forming varnish, other known additives (for example, a crosslinking agent and an antifoaming agent) that can be used for forming the clad layer within a range that does not impair the effect of the clad layer to be formed. , Adhesion aids, etc.) may be included as appropriate.

  The method for producing the clad layer forming varnish is not particularly limited. For example, the material for the clad layer forming varnish (ultraviolet absorber, first polymer, monomer, procatalyst, sensitizer, oxidizing agent in a solvent) And a method for producing a varnish for forming a cladding layer by dissolving an inhibitor or the like. Examples of such a solvent include diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglyme), Ether solvents such as diethylene glycol ethyl ether (carbitol); cellosolv solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve; aliphatic hydrocarbon solvents such as hexane, pentane, heptane, cyclohexane; toluene, xylene, benzene, mesitylene Aromatic hydrocarbon solvents such as pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone and other aromatic heterocyclic compounds solvents; N, N-dimethylformamide (DMF) Amide solvents such as N, N-dimethylacetamide (DMA); Halogen compound solvents such as dichloromethane, chloroform and 1,2-dichloroethane; Ester solvents such as ethyl acetate, methyl acetate and ethyl formate; Dimethyl sulfoxide (DMSO) ) And sulfur compound solvents such as sulfolane. These solvents can be used alone or in combination of two or more.

  Although it does not restrict | limit especially as content of the ultraviolet absorber in such a varnish for clad layer formation, it is preferable that it is 1-10 mass%, and it is more preferable that it is 1-3 mass%. If the content of such an ultraviolet absorber is less than the lower limit, it tends to be difficult to impart sufficient ultraviolet absorption performance to the clad layer 10 to be formed. On the other hand, if the content exceeds the upper limit, the clad layer itself Therefore, the optical confinement in the optical waveguide tends to be insufficient.

  The content ratio of the first polymer in the clad layer forming varnish is not particularly limited, but is preferably 5 to 40% by mass, and more preferably 10 to 35% by mass. If the content ratio of the first polymer is less than the lower limit, the viscosity is too low and it tends to be difficult to form a cladding layer having a desired thickness. On the other hand, if the upper limit is exceeded, the viscosity is too high. It becomes easy to entrain bubbles at the time of application, and the production efficiency tends to decrease.

  Furthermore, the viscosity (normal temperature) of the varnish for forming a clad layer is not particularly limited, and can be appropriately adjusted according to a coating method described later and a desired film thickness. Such a clad layer forming varnish has a viscosity (normal temperature) of preferably 100 to 10000 cP, more preferably 150 to 5000 cP, and still more preferably 200 to 3500 cP.

  Further, as a method of forming the clad layer 10 using such a clad layer forming varnish, for example, a clad layer forming varnish is applied on the core layer, and the clad containing an ultraviolet absorbing component on the core layer Method (I) for forming layer 10, method (II) for forming a clad layer film material (clad film material) in advance using a clad layer forming varnish, and laminating the clad film material on the core layer, etc. Is mentioned. Among these methods, a clad layer can be directly formed on the core layer, and from the viewpoint that the process can be further simplified, a clad layer forming varnish is applied on the core layer and ultraviolet rays are applied on the core layer. It is preferable to employ a method of forming the clad layer 10 containing an absorbing component.

  In such a method (I), the method of applying the clad layer forming varnish is not particularly limited, and examples thereof include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, and a curtain. Examples of the method include a coating method and a die coating method.

  Further, the thickness of the coating film formed by applying the clad layer forming varnish can be appropriately changed according to the design of the optical waveguide, and is not particularly limited, but is about 5 to 200 μm in the state before drying. Preferably, the thickness may be about 15 to 125 μm.

  Moreover, in such a method (I), it is preferable to remove at least a part of the solvent from the coating film after coating the clad layer forming varnish to form the coating film. As the step of removing the solvent (solvent removal step), a known method can be appropriately employed. For example, natural drying, a method of heating, a method of leaving under reduced pressure, or blowing an inert gas ( (Blow) method and a method of evaporating the solvent using a dryer. In this way, a dry coating film can be obtained by removing at least a part of the solvent.

  Furthermore, in the said method (I), it is preferable to form the clad layer 10 by irradiating ultraviolet light after apply | coating the said varnish for clad layer formation. By carrying out such an ultraviolet light irradiation step, the first photoacid generator is used as the ultraviolet light absorber in the clad layer forming varnish, and the side chain containing an epoxy group as the first polymer is used. When the norbornene-based polymer is used, the acid can be released from the first photoacid generator, and the acid can cause cleavage of the epoxy group in the first polymer. It is possible to crosslink the polymers of each other and to improve the adhesion to the core layer. In addition, the cleavage length of the photoacid generator and the generated acid change the conjugate length of the molecules contained in the cladding material. As a result, it is possible to color the cladding film material, which results in an ultraviolet component. Tends to be absorbed easily. In addition, it is preferable to implement such an ultraviolet light irradiation process after the said solvent removal process.

  Moreover, it is preferable that it has a peak wavelength in 200-400 nm as an ultraviolet light in such an ultraviolet light irradiation process, and it is more preferable to have a peak wavelength in 300-400 nm. If the peak wavelength of such ultraviolet light is less than the lower limit, the irradiation time of ultraviolet light tends to be long and the productivity tends to be poor. It tends to be scarce.

Furthermore, it is preferred that the irradiation dose of such ultraviolet light is 100~9000mJ / cm ^2, more preferably 200~6000mJ / cm ^2. If the irradiation amount of the ultraviolet light is less than the lower limit, it tends to be difficult to sufficiently form a cladding layer. On the other hand, if it exceeds the upper limit, chemical degradation of the cladding layer tends to proceed easily. Moreover, it does not restrict | limit especially as a light source for irradiating such ultraviolet light L, A well-known light source (For example, a high pressure mercury lamp etc.) can be used suitably.

  In addition, when the first photoacid generator is of a type that generates acid even by heat, instead of performing the ultraviolet light irradiation step, a heating step is performed to perform the first photoacid generator. The same effect as that in the ultraviolet light irradiation step may be obtained by releasing acid from. The conditions for such heating are not particularly limited, but it is preferable to heat under an inert gas atmosphere at 150 to 200 ° C. for 1 to 2 hours.

  Further, when the clad layer forming varnish contains a monomer and a procatalyst, after the drying step and / or the ultraviolet light irradiation step (or heating step), heating is performed to polymerize the monomer and the clad A film material may be formed. Such heating conditions are not particularly limited, and the heating conditions may be appropriately adjusted according to the type of monomer or procatalyst used.

  Moreover, the said clad film material can be obtained by apply | coating the varnish for clad layer formation on the support base material for film material formation, forming a film, and peeling the film from the said support base material. Such a supporting substrate is not particularly limited, and a known substrate that can be used when forming a film material can be used as appropriate. For example, a silicon substrate, a silicon dioxide substrate, a glass substrate, a quartz substrate can be used. Polyethylene terephthalate (PET) film or the like is used. In addition, as a method for producing such a clad film material, a clad layer forming varnish is applied on the support base material, and after forming the clad layer 10 on the support base material, it is peeled off from the support base material. Except that the clad layer forming varnish is applied on the supporting substrate instead of the clad layer forming varnish on the core layer, and the film material is peeled off from the substrate. The same method as the method (I) for manufacturing the clad layer 10 described above can be adopted.

  Thus, by forming a clad layer using the clad layer forming varnish, the resulting clad layer has a resin component derived from the resin (preferably the first polymer) in the clad layer forming varnish and the above-mentioned The layer contains an ultraviolet absorbing component derived from the ultraviolet absorber.

  Next, the process of forming the core layer 11 on the clad layer 10 of the two-layer laminated substrate shown in FIG. 3 will be described. In the step of forming the core layer 11, the core precursor layer 13 is formed on the clad layer 10, and the core precursor layer 13 is irradiated with ultraviolet light through the photomask 21. This is a step of forming a core layer by forming a cladding portion and a core portion in the non-irradiated region, respectively (step (B)).

  In such a step (B), first, a core precursor layer is formed on the cladding layer 10. Thereby, the three-layer laminated substrate shown in FIG. 4 in which the core precursor layer 13 is laminated on the clad layer 10 of the two-layer laminated substrate shown in FIG. 3 is obtained.

  In the step of forming such a core precursor layer, it is preferable to form the core precursor layer using a core layer forming varnish. Such a core layer forming varnish is not particularly limited as long as it contains a material whose refractive index changes upon irradiation with ultraviolet light, and the core portion and the clad by irradiation with ultraviolet light through a mask to be described later. What contains the well-known material which can form a part can be used suitably.

  Such a varnish for forming a core layer has an absorption maximum wavelength in the ultraviolet region and is irradiated with ultraviolet light from the viewpoint of more reliably achieving both chemical stability during storage and reactivity during use. And a second photoacid generator that releases an acid by the second photoacid generator and a side chain containing a leaving group (leaving pendant group) that is released from the main chain by the acid released by the second photoacid generator. It is preferable to contain two polymers.

  The second photoacid generator contained in such a core layer forming varnish is not particularly limited as long as it has an absorption maximum wavelength in the ultraviolet region and can release an acid by irradiation with ultraviolet light. However, the same thing as the above-mentioned 1st photo-acid generator can be used suitably. Moreover, a suitable thing as a 2nd photo-acid generator is the same as the suitable thing of the above-mentioned 1st photo-acid generator.

  As the second polymer having the leaving group to be contained in such a varnish for forming a core layer, the transparency is sufficiently high (colorless and transparent) and the acid released by the photoacid generator (preferably It is preferable to contain a polymer in which the leaving group is detached (cut) from the side chain by the action of (proton) and its refractive index changes (preferably decreases).

As such a leaving group, from the viewpoint that it is relatively easily released by the acid released from the photoacid generator, in its molecular structure, -O- structure, -Si-aryl structure and -O-Si- Those having at least one of the structures are preferred. Among these leaving groups, from the viewpoint that the refractive index of the polymer can be lowered by leaving, -Si-diphenyl structure (formula: -Si (Ph) ₂ [wherein Ph represents a phenyl group) And a —O—Si-diphenyl structure (formula: —O—Si (Ph) ₂ [wherein Ph represents a phenyl group]). Groups containing a structure are preferred.

Further, the side chain containing the leaving group is not particularly limited as long as it contains the leaving group, and for example, the formula: — (CH ₂ ) _n —CH (CF ₃ ) ₂ —O ^{_{-Si (R 1) 3 ;-( CH}} 2) n -CH (CF 3) 2 -O-CH 2 -O-CH 3 ;-( CH 2) n -CH (CF 3) 2 -O-C ( ^{_{O) -O-C (R 1}} ) 3 ;-( CH 2) n -C (CF 3) 2 -OH ;-( CH 2) n C (O) NH 2 ;-( CH 2) n C (O ^{_{) Cl ;-( CH 2) n C}} (O) OR 1 ;-( CH 2) n-OR 1 ;-( CH 2) n -OC (O) R 1 ;-( CH 2) n -C (O ^{_{) R 1 ;-( CH 2) n}} -OC (O) OR 1 ;-( CH 2) n Si (R 1) 3 ;-( CH 2) n Si (OR 1) 3; - ^{_{CH 2) n -O-Si (}} R 1) 3 ;-( CH 2) n C (O) OR 2; such a group represented the like. In addition, it is preferable that each n in such a formula is an integer of 0 to 10, and R ¹ may be the same or different, and each of hydrogen, linear or branched C ₁ -C ₂₀ alkyl group, a linear or halogenated or perhalogenated alkyl group branched _C 1 _{-C 20,} linear or branched _C 2 _{-C 10} alkenyl group, a linear or branched _C 2 _{-C 10} alkynyl group, C cycloalkyl groups ₅ -C _12, aryl group of C 6 _{-C 14,} be any of the halogenated or aralkyl group perhalogenated aryl, and _C 7 _{-C 24} of C 6 _{-C 14} Preferably, R ² is represented by the formula: —C (CH ₃ ) ₃ ; —Si (CH ₃ ) ₃ ; CH (R ³ ) OCH ₂ CH ₃ ; —CH (R ³ ) OC (CH ₃ ) ₃ ; One of a group or a cyclic group It is preferable that In the formula, R ³ represents a hydrogen atom or a linear or branched alkyl group.

Moreover, as a side chain containing such a leaving group, from the viewpoint that the leaving group can be more efficiently removed by an acid, the formula: — (CH ₂ ) _n —O—Si A group represented by (R ¹ ) ₃ or a formula: — (CH ₂ ) _n —Si (R ¹ ) ₃ is more preferable. Incidentally, n and R ¹ in such expressions are synonymous with those described above. Moreover, among the side chains represented by such a formula, it is more preferable that at least two of R ^{1 in} the formula are phenyl groups. The second polymer having a side chain containing such a leaving group may contain at least one repeating unit having a side chain containing the leaving group in the polymer. It may contain two or more repeating units having a side chain containing the leaving group.

  Examples of the second polymer include cyclic olefin resins such as norbornene resins and benzocyclobutene resins, acrylic resins, methacrylic resins, polycarbonates, which have a side chain containing the leaving group. Examples thereof include polystyrene, epoxy resin, polyamide, polyimide, and polybenzoxazole, and one or more of these can be used (polymer alloy, polymer blend (mixture), copolymer, etc.). The second polymer preferably mainly contains a norbornene-based resin (norbornene-based polymer) having a structure represented by the formula (1) in the main chain. Thus, by using a norbornene-based polymer having a side chain containing the leaving group as the second polymer, an optical waveguide having excellent optical transmission performance and heat resistance can be obtained. In addition, such a norbornene-based polymer makes it possible to obtain an optical waveguide that is less likely to undergo dimensional changes due to water absorption.

  Further, the norbornene-based polymer may be either a polymer having a single repeating unit (homopolymer) or a polymer having two or more norbornene-based repeating units (copolymer). Examples of such norbornene-based polymers include (1) addition (co) polymers of norbornene monomers obtained by addition (co) polymerization of norbornene monomers, and (2) norbornene monomers and ethylene or α-olefins. (3) addition polymers such as addition copolymers with norbornene-type monomers and non-conjugated dienes, and other monomers as required, (4) ring opening of norbornene-type monomers ( A (co) polymer, and a resin obtained by hydrogenating the (co) polymer if necessary, (5) a ring-opening copolymer of a norbornene-type monomer and ethylene or α-olefins, and ( A resin obtained by hydrogenating a (co) polymer, (6) a ring-opening copolymer of a norbornene-type monomer and a non-conjugated diene, or another monomer, and, if necessary, the (co) polymer And a ring-opening polymer such as a polymer obtained by hydrogenation. Examples of these polymers include random copolymers, block copolymers, and alternating copolymers.

  Such a norbornene-based polymer may be any norbornene-based polymer that has a repeating unit of norbornene having a side chain having the leaving group, but has a relatively higher refractive index than the first polymer. It is preferable to use a polymer. By using a norbornene-based polymer having a refractive index relatively higher than that of the first polymer, when the core part is formed, the core part tends to have better optical transmission performance.

  Such a norbornene-based polymer preferably contains a norbornene repeating unit having an alkyl group in the side chain in addition to the norbornene repeating unit having a side chain having a leaving group. . Such alkyl norbornene repeating units are the same as those described in the first polymer.

  Moreover, as a norbornene-type polymer which has such a leaving group, following General formula (3):

[Wherein, R represents an alkyl group, Z represents a side chain containing the leaving group, and X and Y may be the same or different and each represents an integer of 70 or less. ]
A norbornene-based polymer having a structure represented by: In addition, the alkyl group represented by R in the said General formula (3) is the same as the alkyl group of the side chain in the repeating unit of the said alkyl norbornene.

  Further, such a norbornene-based polymer may be selected appropriately from known norbornene-based monomers according to its design, and used in ring-opening metathesis polymerization (ROMP), a combination of ROMP and a hydrogenation reaction, a radical or Manufactured using a known polymerization method such as polymerization using a cation, polymerization using a cationic palladium polymerization initiator, or polymerization using other polymerization initiators (for example, polymerization initiators of nickel and other transition metals). can do.

  Further, when a norbornene-based polymer is mainly used as the second polymer, the content ratio of the norbornene-based polymer in the second polymer is preferably 80 to 100% by mass, and more preferably 95 to 100% by mass. preferable. When such a content ratio is less than the lower limit, the effect obtained by using the norbornene-based polymer tends to be insufficient.

  Moreover, in such a varnish for forming a core layer, it is preferable to further contain a monomer, a procatalyst, a sensitizer, and an antioxidant in addition to the second photoacid absorber and the second polymer. As such monomers, procatalysts, sensitizers, and antioxidants, the same ones as described in the cladding layer forming varnish can be preferably used. The core layer-forming varnish has other known additives (for example, a crosslinking agent and an antifoaming agent) that can be used for forming the core layer within a range that does not impair the effect of the core layer to be formed. , Adhesion aids, etc.) may be included as appropriate.

  Further, the method for producing such a varnish for forming a core layer is not particularly limited, and a known method can be adopted as appropriate. A second photoacid generator is used instead of the ultraviolet absorber, and the first method is used. A method similar to the method of manufacturing the varnish for forming a clad layer described above can be adopted except that the second polymer is used instead of the polymer.

  Further, the content of the second photoacid generator in the core layer forming varnish is not particularly limited, but is preferably 1 to 10% by mass, and more preferably 2 to 5% by mass. . If the content of the second photoacid generator is less than the lower limit, the acid is not sufficiently generated, and it tends to be difficult to proceed the reaction efficiently. The loss of light as a waveguide tends to increase.

  Further, the content ratio of the second polymer in the core layer forming varnish is not particularly limited, but is preferably 70 to 95% by mass, and more preferably 75 to 85% by mass. If the content ratio of the second polymer is less than the lower limit, it tends to be difficult to sufficiently modulate the refractive index, whereas if the upper limit is exceeded, the viscosity of the varnish tends to increase significantly, and filtration tends to be difficult. is there.

  Furthermore, the viscosity (normal temperature) of the varnish for forming the core layer is not particularly limited, and can be appropriately adjusted according to a coating method described later and a desired film thickness. The viscosity (normal temperature) of such a varnish for forming a core layer is preferably 100 to 10000 cP, more preferably 150 to 5000 cP, and still more preferably 200 to 3500 cP.

  Moreover, as a method of forming the core precursor layer using such a core layer forming varnish, for example, the core layer forming varnish is applied on the cladding layer 10 and the core precursor layer is applied on the cladding layer 10. 13, a film material for the core layer (core film material) is formed in advance using a varnish for forming a core layer, and the core film material is laminated on the clad layer. (Ii) etc. which form the core precursor layer 13 in the above. Among such methods, it is preferable to employ the method (i) from the viewpoint that the clad layer can be directly formed on the clad layer and the process can be simplified.

  In such a method (i), as a method for applying the core layer forming varnish onto the clad layer 10, the same method as the method for applying the clad layer forming varnish described above can be employed. In this manner, the core precursor layer 13 can be formed by applying the core layer forming varnish on the clad layer.

  Further, when the core precursor layer 13 is formed by adopting such a method (i), after applying the core layer forming varnish, at least a part of the solvent is removed from the coating film, and the coating is performed. The core precursor layer 13 is preferably formed by drying the film. As the step of removing the solvent (solvent removal step), a known method can be appropriately employed. For example, natural drying, a method of heating, a method of leaving under reduced pressure, or blowing an inert gas ( (Blow) method and a method of evaporating the solvent using a dryer.

  Moreover, the said core film material can be obtained by apply | coating the varnish for core layer formation on the support base material for film material formation, forming a film, and peeling the film from the said support base material. As such a supporting base material, the same one as described in the method for producing the clad film material can be used. Moreover, as a manufacturing method of such a core film material, the varnish for core layer formation is apply | coated on the said support base material, the core precursor layer 13 is formed on a support base material, and this is peeled from a support base material. The core film material may be used, and instead of applying the core layer forming varnish on the clad layer, the core layer forming varnish is applied on the supporting substrate, and after the core precursor layer 13 is formed A method similar to the method (i) for producing the core precursor layer 13 described above is employed except for peeling from the support substrate. In addition, a well-known method is employable suitably as a method of peeling film material from a support base material.

  Next, in the step (B), a step of irradiating the core precursor layer 13 with the ultraviolet light L through the mask 21 is performed (see FIG. 5: FIG. 5 shows the ultraviolet light L applied to the core precursor layer 13). It is a schematic longitudinal cross-sectional view which shows typically the process of irradiating.).

  As the mask (masking) 21, a mask in which an opening (window) equivalent to the shape (pattern) of the clad 11 </ b> A to be formed is formed and the ultraviolet light L can be shielded in a portion other than the opening. By using such a mask 21, the ultraviolet light L is transmitted from the opening, and the ultraviolet light L is shielded at a portion other than the opening (transmission portion), so that the cladding 11 derived from the shape of the opening can be formed. It can be manufactured. The mask 21 may be formed in advance (separately formed) (for example, plate-shaped), or formed on the core precursor layer 13 by, for example, a vapor deposition method or a coating method. A thing may be used.

  As such a mask 21, for example, a photomask made of quartz glass, a PET base material, or the like, a stencil mask, a metal thin film formed by a vapor deposition method (evaporation, sputtering, etc.) is appropriately used. it can. Among such masks 21, it is particularly preferable to use a photomask or a stencil mask from the viewpoints that a fine pattern can be formed with high accuracy and that handling is good and productivity is improved. The constituent material of the mask 21 is not particularly limited, and may be appropriately selected from known materials depending on the peak wavelength of the ultraviolet light L to be irradiated.

  Moreover, it does not specifically limit as the ultraviolet light L irradiated in such a process (B), It is preferable to have a peak wavelength in 200-400 nm, and it is more preferable to have a peak wavelength in 300-400 nm. If the peak wavelength of such ultraviolet light is less than the lower limit, the irradiation time of ultraviolet light tends to be long and the productivity tends to be poor. It tends to be scarce.

Furthermore, it is preferred that the irradiation dose of such ultraviolet light L is 100~9000mJ / cm ^2, more preferably 200~6000mJ / cm ^2, further preferably 200～3000MJ. If the irradiation amount of the ultraviolet light is less than the lower limit, it tends to be difficult to sufficiently form the clad portion. On the other hand, if it exceeds the upper limit, chemical degradation of the clad portion tends to proceed easily. . Moreover, it does not restrict | limit especially as a light source for irradiating such ultraviolet light L, A well-known light source (For example, a high pressure mercury lamp etc.) can be used suitably.

  When the core precursor layer 13 is irradiated with the ultraviolet light L through the mask 21 in this way, the second photoacid generator present in the core precursor layer 13 is the ultraviolet light L in the irradiation region of the ultraviolet light. It reacts (bonds) or decomposes by action to generate an acid (preferably a proton). Then, such an acid releases a leaving group from the second polymer in the ultraviolet light irradiation region in the core precursor layer 13 (photo bleach). Therefore, in the irradiation region of the ultraviolet light L, compared to the non-irradiation region of the ultraviolet light L, the polymer (the leaving group from the side chain) in the same state as the second polymer that existed before the ultraviolet light irradiation. The number of polymers that are not desorbed decreases. And in the irradiation area | region of the ultraviolet light L, the content rate of the polymer from which the leaving group detach | desorbed from the 2nd polymer, and the component derived from this increases. Thereby, the refractive index of the irradiation region of the ultraviolet light is lower than that before the irradiation of the ultraviolet light. On the other hand, in the non-irradiated region of the ultraviolet light L, the second polymer remains in a substantially complete state, so that the refractive index from the beginning is sufficiently maintained. In this way, the state of the existing polymer differs between the irradiation region of the ultraviolet light L and the non-irradiation region, so that the refractive index of the non-irradiation region of the ultraviolet light L in the layer 13 (first refractive index). ) And the refractive index (second refractive index) of the irradiation region of the ultraviolet light L in the layer 13, a refractive index difference (second refractive index <first refractive index) is generated, and the cladding portion 14 </ b> A ( It is possible to form the core layer 11 in which the irradiation region) and the core portion 11B (non-irradiation region) are formed.

  In the step of forming the core layer 11 (step (B)), the cladding layer 10 contains an ultraviolet absorbing component in the step of irradiating the core precursor layer 13 with the ultraviolet light L. The influence of the ultraviolet light L can be reduced in the core layer 11 that absorbs the ultraviolet light L and is laminated on the other surface side of the clad layer 10 on which the core precursor layer 13 is formed. Therefore, in the present invention, the step (A) and the step (B) can be sequentially repeated, and an optical waveguide having a multilayer structure can be efficiently manufactured.

  In addition, after the core portion 14A and the clad portion 14B are formed in the non-irradiated region and the irradiated region of the ultraviolet light L in this way, the formed core layer 14 can be subjected to heat treatment. preferable. By such a heat treatment, it becomes possible to remove the leaving group detached (cut) from the second polymer from the irradiation region of the ultraviolet light L, and to rearrange or crosslink within the second polymer. Further, it is assumed that a part of the remaining leaving group bonded to the polymer in the clad portion 14B is further detached (cut) by such heat treatment. Therefore, by performing such heat treatment, it becomes possible to further increase the refractive index difference between the core portion 14A and the clad portion 14B.

  Further, when the above-mentioned monomer and procatalyst are contained in the core varnish together with the second photoacid generator and the second polymer by such heat treatment, the following phenomenon occurs. That is, first, in the irradiation region of the ultraviolet light L, the molecular structure of the procatalyst is changed (decomposed) by the action of the acid generated from the second photoacid generator, so that the procatalyst is in an active latent state (potential (Active state). After that, when the core precursor layer is subjected to heat treatment, the active catalyst procatalyst becomes active, so that the monomer reaction (polymerization reaction or crosslinking reaction) is induced in the irradiation region of the ultraviolet light L. Occur. As the monomer reaction proceeds, the monomer concentration in the irradiation region of the ultraviolet light L gradually decreases, and a difference occurs in the monomer concentration between the irradiation region of the ultraviolet light L and the non-irradiation region 940. In the core precursor layer 13, a phenomenon occurs in which the monomer diffuses from the non-irradiated region and the monomer collects in the irradiated region in order to eliminate the difference in monomer concentration. Therefore, in the irradiation region of the ultraviolet light L in the core precursor layer 13, the monomer and the reaction product (polymer, cross-linked structure or branched structure) increase, and the structure derived from the monomer has a refractive index of the region. Will greatly affect As a result, in the ultraviolet light irradiation region, the refractive index is lowered by the heat treatment after the ultraviolet light irradiation. On the other hand, in the non-irradiated region of the ultraviolet light L, the monomer diffuses from that region, so that the amount of monomer decreases, the influence of the second polymer appears greatly, and the refractive index changes to higher refractive index. Therefore, by performing such heat treatment, it becomes possible to further increase the refractive index difference between the core portion 14A and the clad portion 14B.

  Furthermore, the heat treatment conditions after the irradiation with ultraviolet light L are not particularly limited, but the heating temperature is 70 to 195 ° C. (more preferably 85 to 150 ° C.), and the heating time is 0.5 to 3 hours (more Preferably it is 0.5 to 2 hours). In addition, such a heat treatment may be omitted when a sufficient refractive index difference is obtained between the core portion 14A and the clad portion 14B before the heat treatment is performed.

  Next, the process of manufacturing the core layer laminated base material shown in FIG. 2 prepared before implementing the said process (A) and process (B) is demonstrated.

  The process of manufacturing such a core layer laminated base material is the same as the process (B) except that the core layer 11 is formed on the base material instead of forming the core layer 11 on the clad layer 10. It is preferable to adopt. That is, the process of manufacturing such a core layer laminated base material includes forming a core layer precursor layer on the base material, irradiating the core precursor layer with ultraviolet light through a photomask, and irradiating with ultraviolet light. It is preferable to form a core layer having a clad part and a core part on a substrate by forming a clad part and a core part in the region and the non-irradiated region, respectively. In addition, it does not restrict | limit especially as such a base material, For example, a silicon substrate, a silicon dioxide substrate, a glass substrate, a quartz substrate, a polyethylene terephthalate (PET) film etc. are mentioned.

  In this way, the core layer laminated base material is prepared, and the layers are laminated on the base material 20 in the order of the core layer / cladding layer / core layer by carrying out the step (A) and the step (B). A second three-layer laminated substrate as shown in FIG. 6 can be obtained. And it becomes possible to obtain the optical waveguide shown in FIG. 1 by peeling a base material from such a 2nd 3 layer laminated base material. The method for peeling off such a substrate is not particularly limited, and a known method can be appropriately employed.

  The preferred embodiments of the optical waveguide of the present invention and the method of manufacturing the optical waveguide of the present invention have been described above. However, the optical waveguide of the present invention and the method of manufacturing the optical waveguide of the present invention are not limited to the above embodiments. Absent. For example, the embodiment of the optical waveguide 1 shown in FIG. 1 is an optical waveguide having a three-layer structure in which a core layer / cladding layer / core layer are laminated in this order. However, in the optical waveguide of the present invention, a plurality of core layers 11 are used. However, the number of layers is not particularly limited, and can be configured to have various numbers of layers according to the intended application. A four-layer optical waveguide laminated in the order of core layer / cladding layer / core layer, and a five-layer optical waveguide laminated in the order of clad layer / core layer / cladding layer / core layer / cladding layer as shown in FIG. Waveguide, optical layer having a five-layer structure in which core layer / clad layer / core layer / clad / core layer are laminated in this order, and six layers laminated in the order of core layer / clad layer / core layer / clad / core layer / clad layer Multiple cores such as structured optical waveguides Include those of 3 or more layers having 11. Moreover, the optical waveguide of the present invention may be in the form of being placed on various substrates according to the intended application. Furthermore, the optical waveguide of the present invention may be formed directly on the base material of an electric device.

  In the embodiment of the optical waveguide, the size (width) and arrangement position of the clad portion 11A and the core portion 11B in the core layer 11 are the same in each core layer 11, but the optical waveguide of the present invention The size and arrangement position of the clad part 11A and the core part 11B in the core layer 11 are not particularly limited, and the design can be appropriately changed for each core layer according to the intended use. An arrangement as shown in FIG. Further, in the embodiment shown in FIG. 1, the direction of the optical axis of the light when propagating the light to the core portion 11B in each core layer is in the same direction. The direction of the core part 11B is not particularly limited, and the direction of the optical axis of the light transmitted by the core part 11B may be different in each core layer.

  In the embodiment of the method for manufacturing an optical waveguide described above, a method is used in which the core layer laminated base material shown in FIG. 2 is prepared and the process (A) and the process (B) are performed once. The method for producing an optical waveguide of the present invention may be any method including the steps (A) and (B) and obtaining an optical waveguide in which a plurality of core layers are laminated with a clad layer as an intermediate layer. Before carrying out the steps (A) and (B), a clad layer laminated substrate having a clad layer formed on the substrate is prepared, and a core layer is formed on the clad layer of the clad layer laminated substrate. Thereafter, the step (A) and the step (B) may be performed to manufacture an optical waveguide having a structure in which a plurality of core layers are laminated with a clad layer as an intermediate layer. As described above, in the method of manufacturing an optical waveguide according to the present invention, before performing the steps (A) and (B), the core precursor layer is formed on the base material or on the clad layer formed on the base material. And irradiating the core precursor layer with ultraviolet light through a photomask to form a clad part and a core part in an ultraviolet light irradiation region and a non-irradiation region, respectively. What is necessary is just to form the core layer which has. In addition, the process of preparing such a clad layer laminated base material adopts the same method as the above-mentioned process (A) except that the clad layer is formed on the base material instead of forming the clad layer on the core layer. it can. Moreover, it is preferable to employ | adopt the said process (B) as a process of forming a core layer on the clad layer of a clad layer laminated base material.

  In the embodiment of the method for manufacturing an optical waveguide described above, the core layer laminated substrate shown in FIG. 2 is prepared, and the steps (A) and (B) are performed in the order of step (A) and step (B). However, in the method of manufacturing an optical waveguide of the present invention, the steps (A) and (B) may be included, and the steps (A) and (B) are performed. The number of times to perform and the order of execution are not particularly limited. For example, one of step (A) and step (B) may be performed a plurality of times, and step (A) and step (B) are each performed a plurality of times. Further, step (B) may be performed before step (A). Although it does not restrict | limit especially as a method of implementing one of such a process (A) and a process (B) in multiple times, For example, the core layer laminated base material in which the core layer was formed on the base material was prepared. An optical waveguide having a four-layer structure in which the steps are performed in the order of the step (A), the step (B), and the step (A) to laminate the base material / core layer / cladding layer / core layer / cladding layer in this order. A manufacturing method and a clad layer laminated base material in which a clad layer is formed on a base material are prepared, and each step is performed in the order of step (B), step (A), step (B). Examples thereof include a method of manufacturing an optical waveguide having a four-layer structure in which materials / clad layers / core layers / clad layers / core layers are laminated in this order. In addition, the method of performing the step (A) and the step (B) a plurality of times is not particularly limited. For example, a clad layer laminated base material in which a clad layer is formed on a base material is prepared, and the step (B) A method of manufacturing an optical waveguide having a five-layer structure in which each step is performed twice in the order of step (A) and laminated in the order of base material / cladding layer / core layer / cladding layer / core layer / cladding layer, A clad layer laminated base material in which a clad layer is formed on a base material is prepared, and each step is sequentially performed four times in the order of step (B) and step (A), and the base material / cladding layer / core layer For example, a method of manufacturing an optical waveguide having a nine-layer structure laminated in the order of / clad layer / core layer / clad layer / core layer / clad layer / core layer / clad layer. As described above, in the method of manufacturing an optical waveguide of the present invention, the number of times and the order in which the step (A) and the step (B) are performed are not particularly limited, and depending on the design of the target optical waveguide, Each of the steps (A) and (B) may be performed once or more. In the method for manufacturing an optical waveguide according to the present invention, when the core precursor layer 13 is irradiated with the ultraviolet light L in the step (B), the cladding layer 10 absorbs the ultraviolet light L, so the core precursor layer 13. The ultraviolet light L has no influence on the core layer 11 laminated on the other surface of the clad layer 10 on which is formed. Therefore, the step (A) and the step (B) can be sequentially repeated, and an optical waveguide having a multilayer structure can be manufactured efficiently.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Synthesis Example 1: Synthesis of hexyl norbornene (HxNB) / diphenylmethylnorbornene methoxysilane (diPhNB) copolymer)
First, HxNB (CAS number: 22094-83-3) (9.63 g, 0.054 mol), diPhNB (CAS number: 376634-34-3) (40.37 g, 0.126 mol), 1-hexene (4.54 g, 0.054 mol) and toluene (150 g) were mixed in a 500 mL sealam bottle in a dry box, and stirred while heating to 80 ° C. in an oil bath to obtain a solution. Obtained. Next, Pd (PCy ₃ ) ₂ (OAc) (CNMe) [Pd1446, 1.04 × 10 ⁻² g, 7.20 × 10 ⁻⁶ mol] and N, N-dimethylanilinium tetrakis ( Pentafluorophenyl) borate (abbreviation: DANFABA, 2.30 × 10 ⁻² g, 2.88 × 10 ⁻⁵ mol) was added in the form of a concentrated dichloromethane solution (0.1 mL), respectively, to obtain a mixture. The mixture was then stirred with a magnetic stirrer at 80 ° C. for 2 hours. Thereafter, the reaction mixture (toluene solution) was transferred to a larger beaker, and methanol (1 L) as a poor solvent was added dropwise thereto to precipitate a fibrous white solid. Next, the solid matter thus precipitated was filtered and vacuum-dried in an oven at 60 ° C. to obtain a product having a dry mass of 19.0 g (yield 38%). When the molecular weight of the product thus obtained was measured by gel permeation chromatography (GPC: THF solvent, polystyrene conversion), the mass average molecular weight (Mw) was 118,000, and the number average molecular weight (Mn) was 60,000. Further, the obtained product was measured by 1H-NMR, and was represented by the following structural formula: HxNB / diPhNB-based copolymer (in the following structural formula: x = 0.32, y = 0.68, n = 5). I identified it. When the refractive index of this copolymer was measured by the prism coupling method, the TE mode was 1.5695 and the TM mode was 1.5681 at a wavelength of 633 nm.

(Synthesis Example 2: Preparation of varnish for forming core layer)
First, under yellow light, the HxNB / diPhNB copolymer obtained in Synthesis Example 1 was dissolved in mesitylene to prepare a 10% by mass copolymer solution (30 g). Separately, in a 100 mL glass bottle, HxNB (42.03 g, 0.24 mol) and bis-norbornenemethoxydimethylsilane (SiX, CAS number: 376609-87-9) (7.97 g, 0 .026 mol) was added, and two kinds of antioxidants [Irganox 1076 (0.5 g) and Irgafos 168 (0.125 g) manufactured by Ciba) were added to obtain a monomer antioxidant solution.

Next, 30.0 g of the copolymer solution was added to 3.0 g of the monomer antioxidant solution and Pd (PCy ₃ ) ₂ (OAc) ₂ (Pd785) (4.95 × 10 ⁻⁴ g per 0.1 mL of methylene chloride. , 6.29 × 10 ⁻⁷ mol) and a photoacid generator [RHODORSIL (registered trademark) PHOTOINITIATOR 2074 (CAS number: 178233-72-2)] having an absorption maximum wavelength of 220 nm (per 0.1 mL of methylene chloride, 2.55 × 10 ⁻³ g, 2.51 × 10 ⁻⁶ mol) was added and dissolved uniformly, and then filtered through a filter having a pore diameter of 0.2 μm to prepare a varnish for forming a core layer.

(Synthesis Example 3: Synthesis of Decyl Norbornene (DeNB) / Methyl Glycidyl Ether Norbornene (AGENB) Copolymer)
First, DeNB (CAS number: 22094-85-5) (16.4 g, 0.07 mol), AGENB (CAS number: 3188-75-8) (5.41 g, 0.03 mol) and Toluene (58.0 g) was mixed in a 500 mL sealam bottle in a dry box and further stirred while heating to 80 ° C. in an oil bath to obtain a solution. Next, a toluene solution (5 g) of (η ⁶ -toluene) Ni (C ₆ F ₅ ) ₂ (0.69 g, 0.0014 mol) was added to the solution to obtain a mixture. Next, the mixture after such addition was stirred with a magnetic stirrer at room temperature for 4 hours, toluene (87.0 g) was added to the mixture after stirring, and the mixture was vigorously stirred to obtain a reaction mixture. Thereafter, the reaction mixture (toluene solution) was transferred to a larger beaker, and methanol (1 L) as a poor solvent was added dropwise thereto to precipitate a fibrous white solid. Next, the solid matter thus precipitated was collected by filtration and vacuum-dried in an oven at 60 ° C. to obtain a product having a dry mass of 17.00 g (yield 87%). When the molecular weight of the product thus obtained was measured by GPC (THF solvent, polystyrene conversion), Mw was 75,000 and Mn was 30,000. The obtained product is measured by 1H-NMR, and is a DeNB / AGENB copolymer represented by the following structural formula (in the following structural formula: x = 0.77, y = 0.23, n = 10). Was identified. When the refractive index of the copolymer thus obtained was measured by the prism coupling method, the TE mode was 1.5153 and the TM mode was 1.5151 at a wavelength of 633 nm.

(Synthesis Example 4: Preparation of varnish for forming clad layer)
Under yellow light, 10 g of the DeNB / AGENB copolymer was dissolved in dehydrated toluene to prepare a 20% by mass copolymer solution (50 g). To this solution, two kinds of antioxidants [Irganox 1076 (0.01 g) and Irgafos 168 (0.0025 g) manufactured by Ciba) and a photoacid generator having an absorption maximum wavelength of 335 nm (trade name “TAG- 382 ") (0.2 g) was added and dissolved uniformly, and then filtered through a filter having a pore size of 0.2 µm to prepare a varnish for forming a cladding layer.

Example 1
First, 10 g of the clad varnish obtained in Synthesis Example 4 was poured onto a PET film having a thickness of 100 μm arranged on a horizontal base, and spread so that the thickness of the clad varnish was almost constant with a doctor blade. A coating film was formed (thickness before drying: 30 μm). Next, the formed coating film is put into a dryer together with a PET film and heated at 50 ° C. for 15 minutes to evaporate toluene to form a clad layer having a dry coating thickness of 20 μm on the substrate. A forming substrate was obtained.

Next, 10 g of the core layer forming varnish obtained in Synthesis Example 2 is poured onto the cladding layer of the cladding layer forming base material, and this is spread with a doctor blade so as to have a substantially constant thickness. A varnish coating film was formed (thickness before drying: 70 μm). Next, the laminate on which the coating film is formed is put into a dryer and heated at 50 ° C. for 45 minutes to evaporate toluene, and a core precursor layer made of a dried coating film having a thickness of 50 μm is formed on the cladding layer. Formed. Next, the core precursor layer was irradiated with ultraviolet light having a wavelength of 365 nm or less using a metal halide lamp through a photomask having a predetermined opening pattern (irradiation amount: 500 mJ / cm ² ). Next, the coating film after irradiation with ultraviolet light is placed in an oven, and first subjected to heat treatment at 50 ° C. for 30 minutes, then at 85 ° C. for 30 minutes, and then at 150 ° C. for 60 minutes. A core layer having a clad portion was formed (hereinafter, a process of forming a core layer on the clad layer in this way is referred to as a “core layer forming process”). In such a heat treatment, the waveguide pattern in the coating film could be visually confirmed at the time of heating at the first 50 ° C. for 10 minutes. Further, it has been found that such a waveguide pattern is derived from the opening pattern of the photomask used. In this way, by forming a core layer on the clad layer, a two-layer laminate in which the clad layer and the core layer were laminated in the order of clad layer / core layer on the base material was obtained.

  Next, 10 g of the clad varnish obtained in Synthesis Example 4 is poured onto the core layer of the two-layer laminate, and spread with a doctor blade so as to have a substantially constant thickness, thereby forming a clad varnish coating film. (Thickness before drying: 30 μm). Next, the laminate on which the coating film is formed is put in a dryer and heated at 50 ° C. for 15 minutes to evaporate toluene, thereby forming a clad layer made of a dried coating film having a thickness of 20 μm on the core layer. (Hereinafter, the process of forming the clad layer on the core layer in this way is referred to as “clad layer forming process”). In this way, a clad layer was formed on the core layer to obtain a three-layer laminate in which the clad layer and the core layer were laminated on the base material in the order of clad layer / core layer / cladding layer.

  Next, the core layer forming step and the clad layer forming step are alternately performed three times each, and the core layer and the clad layer are alternately stacked on the clad layer of the three-layer laminated body. An optical waveguide in which a clad layer and a core layer were laminated on the material in the order of clad layer / core layer / cladding layer / core layer / cladding layer / core layer / cladding layer / core layer / cladding layer was produced. In addition, in each core layer formation process, the pattern of the opening part of the mask to be used was each changed. A photograph showing the state of the thin film thus laminated is shown in FIG.

  As is apparent from the results shown in FIG. 9, it can be seen that a clad portion and a core portion corresponding to the mask pattern are formed in each core layer. In the optical waveguide thus formed, the refractive index of the core portion was 1.54, the refractive index of the cladding portion was 1.53, and the refractive index of the cladding layer was 1.51. Further, in such a method of manufacturing an optical waveguide (Example 1), ultraviolet light is irradiated when forming the core layer, but the ultraviolet light irradiated when forming a new core layer is already formed. It has been found that there is no effect on the core layer. From these results, according to the optical waveguide manufacturing method (Example 1) of the present invention, the core layer forming step and the clad layer forming step can be carried out continuously, and a plurality of core layers can be clad in a simple process. It was confirmed that an optical waveguide having a multilayer structure laminated through layers could be formed.

  In addition, when light generated from a surface emitting laser (VCSEL) is input to one end of each core portion of the optical waveguide thus obtained through an optical fiber, light is output from the other end in all the core portions. It was confirmed that light can be propagated. From these results, it can be seen that according to the optical waveguide of the present invention (Example 1), high-speed and high-capacity transmission of information signals can be achieved by using the core portion formed in each layer.

  As described above, according to the present invention, a plurality of core layers have a multilayer structure in which a cladding layer is used as an intermediate layer, enabling optical wiring with a complicated design, and high-speed, high-capacity transmission of information signals. It is possible to provide an optical waveguide that can be realized, and to efficiently manufacture an optical waveguide with a complex design having a multilayer structure in which a plurality of core layers are laminated with a cladding layer as an intermediate layer in a simple process It becomes possible to provide a manufacturing method of a simple optical waveguide. Therefore, the present invention is very useful as a technique related to high density optical wiring.

It is a schematic longitudinal cross-sectional view which shows suitable one Embodiment of the optical waveguide of this invention. It is a schematic longitudinal cross-sectional view of the core layer laminated base material by which the core layer was laminated | stacked on the base material. It is a schematic longitudinal cross-sectional view of the 2 layer laminated base material by which the core layer and the clad layer were laminated | stacked on the base material. It is a schematic longitudinal cross-sectional view of the 3 layer laminated base material by which the core layer, the clad layer, and the core precursor layer were laminated | stacked on the base material. It is a schematic longitudinal cross-sectional view which shows typically the state which has irradiated the ultraviolet light to the core precursor layer. It is a schematic longitudinal cross-sectional view of the 2nd three-layer laminated base material by which the core layer, the clad layer, and the core layer were laminated | stacked on the base material. It is a schematic longitudinal cross-sectional view which shows other suitable embodiment (5 layer optical waveguide) of the optical waveguide of this invention. It is a schematic longitudinal cross-sectional view which shows other suitable embodiment (3 layer structure optical waveguide) of the optical waveguide of this invention. It is a photograph which shows the state of the thin film laminated | stacked on the base material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical waveguide, 10 ... Cladding layer, 11 ... Core layer, 11A ... Cladding part, 11B ... Core part, 20 ... Base material, 21 ... Mask, L ... Ultraviolet light.

Claims (21)

  A plurality of core layers having a clad part and a core part are laminated with the clad layer as an intermediate layer, and the core layer and the clad layer each contain a resin component, and the core part is the clad part And an optical waveguide having a refractive index relatively higher than that of the cladding layer, and the cladding layer contains an ultraviolet absorbing component.   The ultraviolet absorbing component is selected from the group consisting of a first photoacid generator having an absorption maximum wavelength in the ultraviolet region and releasing an acid upon irradiation with ultraviolet light, and a component derived from the first photoacid generator. The optical waveguide according to claim 1, wherein the optical waveguide is at least one component.   The optical waveguide according to claim 2, wherein the absorption maximum wavelength of the first photoacid generator is 300 to 400 nm.   The first photoacid generator is at least one photoacid generator selected from the group consisting of aluminates, antimonates, borates, gallates, carboranes and halocarboranes. The optical waveguide according to claim 2 or 3, characterized in that Said first photoacid generator has the formula: -S (Ph) ₂ , -S ⁺ (Ph) ₃ , -I (Ph) _2, and -I ⁺ (Ph) ₃ [wherein Ph represents a phenyl group. Show. The optical waveguide according to any one of claims 2 to 4, wherein the optical waveguide comprises a compound having at least one of the structures represented by the formula:   The optical waveguide according to any one of claims 1 to 5, wherein the clad layer contains a norbornene-based polymer.   The core portion contains a norbornene-based polymer having a refractive index relatively higher than the resin component in the cladding layer, and the cladding portion is relatively lower than the norbornene-based polymer contained in the core portion. The optical waveguide according to claim 1, comprising a norbornene-based polymer having a refractive index. The following steps (A) and (B):
[Step (A)] A step of forming a clad layer containing an ultraviolet absorbing component on the core layer;
[Step (B)] A core precursor layer is formed on the clad layer, and the core precursor layer is irradiated with ultraviolet light through a photomask, and the ultraviolet light irradiated region and the non-irradiated region are respectively coated with the cladding portion and Forming a core layer having a clad portion and a core portion by forming a core portion;
And an optical waveguide in which a plurality of core layers are laminated with a clad layer as an intermediate layer.   Before carrying out the steps (A) and (B), a core precursor layer is formed on a base material or a clad layer formed on the base material, and the core precursor layer is passed through a photomask. 9. A core layer having a clad portion and a core portion is formed by irradiating ultraviolet light, forming a clad portion and a core portion in an ultraviolet light irradiation region and a non-irradiation region, respectively. The manufacturing method of the optical waveguide as described in any one of.   10. The optical waveguide according to claim 8 or 9, wherein the step (A) is a step of forming a clad layer by applying a clad layer forming varnish containing an ultraviolet absorber on the core layer. Production method.   The step (A) is a step of forming a cladding layer by irradiating with ultraviolet light after applying a cladding layer forming varnish containing an ultraviolet absorber on the core layer. The manufacturing method of the optical waveguide as described in any one of these.   The step of forming the core precursor layer is a step of applying a core layer forming varnish on the clad layer to form a core precursor layer. The manufacturing method of the optical waveguide as described in a term.   The clad layer forming varnish contains a first photoacid generator having an absorption maximum wavelength in an ultraviolet region and releasing an acid upon irradiation with ultraviolet light, and a first polymer. A method for producing an optical waveguide according to 10 or 11.   The method of manufacturing an optical waveguide according to claim 13, wherein the absorption maximum wavelength of the first photoacid generator is 300 to 400 nm.   The first photoacid generator is at least one photoacid generator selected from the group consisting of aluminates, antimonates, borates, gallates, carboranes, and halocarboranes. 15. The method for manufacturing an optical waveguide according to claim 13, wherein the optical waveguide is manufactured. The first photoacid generator is -S (Ph) ₂ , -S ⁺ (Ph) ₃ , -I (Ph) _2, and -I ⁺ (Ph) ₃ [wherein Ph represents a phenyl group. The method for producing an optical waveguide according to claim 13, comprising a compound having at least one of structures represented by the formula:   The method for producing an optical waveguide according to any one of claims 13 to 16, wherein the first polymer is a norbornene-based polymer having a side chain containing a polymerizable group.   The method for producing an optical waveguide according to claim 13, wherein the first polymer is a norbornene-based polymer having a side chain containing an epoxy group.   The core layer forming varnish is separated by a second photoacid generator having an absorption maximum wavelength in the ultraviolet region and releasing an acid upon irradiation with ultraviolet light, and an acid released by the second photoacid generator. The method for producing an optical waveguide according to claim 12, comprising a second polymer having a side chain containing a leaving group.   The method for producing an optical waveguide according to claim 19, wherein the second polymer is a norbornene-based polymer having a side chain containing the leaving group. 21. The group according to claim 19 or 20, wherein the leaving group is a group containing at least one structure of structures represented by the formula: -O-, -Si-, and -O-Si-. Manufacturing method of the optical waveguide.