Self-forming optical waveguide composition, self-forming optical waveguide, and method for manufacturing self-forming optical waveguide

Abstract

The present invention addresses the problem of providing a self-forming optical waveguide composition that forms a self-forming optical waveguide easily. The present invention also addresses the problem of providing a self-forming optical waveguide and a method for manufacturing the self-forming optical waveguide.　A self-forming optical waveguide composition according to the present invention contains two or more types of polymerizable compounds. The polymerization mechanisms of the two or more types of polymerizable compounds are the same.

Description

Composition for self-forming optical waveguide, self-forming optical waveguide, method for producing self-forming optical waveguide

[0001] The present invention relates to a composition for a self-written optical waveguide, a self-written optical waveguide, and a method for producing an optical waveguide.

[0002] In fields such as optical communications, optical information processing, electronic devices, and optical equipment that utilize optical technology, development of optical waveguides used to connect various optical devices is progressing. Optically connecting various optical devices using optical waveguides requires extremely high-precision alignment of optical axes. Conventionally, such alignment work has been performed manually or using high-precision equipment, but it has been problematic in terms of labor and time required. From this perspective, self-written optical waveguide technology, in which an optical waveguide is manufactured by self-forming the core of the optical waveguide from a photocurable resin, has been studied. A self-written optical waveguide can be formed at the end of an optical fiber or the like by, for example, immersing the end of an optical fiber or the like in the photocurable resin and irradiating light from the optical fiber or the like into the photocurable resin to gradually harden the photocurable resin.

[0003] For example, Patent Document 1 describes a core-forming composition for a self-forming optical waveguide, in which a composition containing a (meth)acrylate having a COOH group and a photopolymerization initiator is used as a material for photo-curing the core of the self-forming optical waveguide, and also describes a self-forming optical waveguide in which the core is a cured product obtained by photo-curing the core-forming composition (see Claims 1, 15, etc.).

[0004] JP 2011-034054 A

[0005] The present inventors attempted to form a self-forming optical waveguide using the self-forming optical waveguide composition described in Patent Document 1, and found that the process of removing uncured components around the core portion after the core portion is formed is complicated and there is room for improvement.

[0006] An object of the present invention is to provide a composition for a self-written optical waveguide that allows easy formation of a self-written optical waveguide. Another object of the present invention is to provide a self-written optical waveguide and a method for manufacturing a self-written optical waveguide.

[0007] The present inventors conducted extensive research to solve the above-mentioned problems and found that the following configurations can solve the above-mentioned problems. [1] A self-forming optical waveguide composition comprising two or more polymerizable compounds, wherein the two or more polymerizable compounds have the same polymerization mechanism. [2] The self-forming optical waveguide composition according to [1], wherein the polymerization mechanism is at least one selected from radical polymerization, cationic polymerization, and anionic polymerization. [3] The self-forming optical waveguide composition according to [1] or [2], wherein the two or more polymerizable compounds at least comprise a combination of two polymerizable compounds having a difference in refractive index of 0.05 or more. [4] The self-forming optical waveguide composition according to any one of [1] to [3], wherein the two or more polymerizable compounds at least comprise a combination of two polymerizable compounds having the same polymerization mechanism but different numbers of polymerizable groups in one molecule. [5] The self-forming optical waveguide composition according to any one of [1] to [4], wherein none of the two or more polymerizable compounds has a thio(meth)acrylate group. [6] The self-forming optical waveguide composition according to any one of [1] to [5], wherein the viscosity of the self-forming optical waveguide composition at 25° C. is 500 to 100,000 mPa·s. [7] A self-forming optical waveguide produced using the self-forming optical waveguide composition according to any one of [1] to [6]. [8] A method for producing a self-forming optical waveguide using the self-forming optical waveguide composition according to any one of [1] to [6], the method comprising the steps of: preparing a first optical element, a second optical element, and the self-forming optical waveguide composition disposed between the first optical element and the second optical element; irradiating light from at least one of the first optical element and the second optical element to cure the self-forming optical waveguide composition and form a core portion; and exposing uncured components in the self-forming optical waveguide composition to form a clad portion, thereby forming a self-forming optical waveguide including the core portion and the clad portion.

[0008] According to the present invention, it is possible to provide a composition for a self-written optical waveguide that allows easy formation of a self-written optical waveguide. Furthermore, according to the present invention, it is possible to provide a self-written optical waveguide and a method for manufacturing a self-written optical waveguide.

[0009] Fig. 1 is a schematic diagram showing an example of a method for producing a self-written optical waveguide. Fig. 2 is a schematic diagram showing an example of a method for producing a self-written optical waveguide. Fig. 3 is a schematic diagram showing an example of a method for producing a self-written optical waveguide. Fig. 4 is a schematic diagram showing another example of a method for producing a self-written optical waveguide. Fig. 5 is a schematic diagram showing another example of a method for producing a self-written optical waveguide. Fig. 6 is a schematic diagram showing another example of a method for producing a self-written optical waveguide.

[0010] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In each drawing, the scale of the components may differ from the actual scale in order to make it easier to see and explain.

[0011] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the numerical ranges described in stages in this specification, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the Examples. In this specification, each component may be a single substance corresponding to the component, or two or more substances may be used in combination. Here, when two or more substances are used in combination for each component, the content of that component refers to the total content of the substances used in combination, unless otherwise specified.

[0012] In this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", and "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl". In this specification, the number average molecular weight (Mn) and weight average molecular weight (Mw) are values ​​measured by size exclusion chromatography (gel permeation chromatography) using polystyrene as a standard substance.

[0013] As used herein, "orthogonal" or "perpendicular" refers to a range of 90°±5°, and "parallel" refers to a range of 0°±5°. Similarly, unless otherwise specified, angles refer to angles that are within a range of 5 degrees from the exact angle. The difference in the angle is preferably within 4 degrees, and more preferably within 3 degrees. As used herein, visible light refers to light with wavelengths visible to the human eye, in the wavelength range of 380 to 780 nm. Ultraviolet light (UV) refers to light with a wavelength range of 10 nm or more and less than 380 nm, and infrared light (IR) refers to light with a wavelength range exceeding 780 nm.

[0014] [Self-forming optical waveguide composition] The self-forming optical waveguide composition according to the present invention (hereinafter also referred to as "the composition") is a self-forming optical waveguide composition containing two or more polymerizable compounds, the polymerization mechanisms of which are the same for the two or more polymerizable compounds.

[0015] The present composition allows for easy formation of a self-forming optical waveguide. When forming an optical waveguide by self-forming (self-assembly) using a composition containing a reactive compound, a process with fewer steps is desirable from the standpoint of takt time. The method described in Patent Document 1 requires, after forming a core, the removal of uncured components around the core and then refilling the core with a cladding composition, resulting in a cumbersome process. Furthermore, if the core and cladding need to be exposed to light using different light sources, the configuration of the manufacturing equipment and composition may become complex, affecting process management. In response to this, the present inventors discovered that a composition containing two or more polymerizable compositions, which have the same polymerization mechanism and are therefore curable with the same light source, can more easily form a self-forming optical waveguide, thereby completing the present invention. The composition of the present composition is described in more detail below.

[0016] The composition contains two or more polymerizable compounds. The composition may contain components other than the polymerizable compounds. Examples of the other components include a polymerization initiator and various additives that are added as needed.

[0017] (Polymerizable Compound) The present composition contains two or more polymerizable compounds with the same polymerization mechanism. In this specification, the phrase "having the same polymerization mechanism" in relation to different types of polymerizable compounds means that the respective polymerizable compounds have polymerizable groups with the same polymerization mechanism, i.e., polymerizable groups with the same active species generated by reaction. For example, when the first polymerizable compound and the second polymerizable compound contained in the present composition both have radical polymerizable groups that generate radicals as propagating active species by reaction, it can be said that the first polymerizable compound and the second polymerizable compound have the same polymerization mechanism. Furthermore, the phrase "different types" in relation to multiple polymerizable compounds means that at least a portion of the structure of each polymerizable compound other than the same polymerizable group is different from each other.

[0018] Hereinafter, unless otherwise specified, the expression "polymerizable compound" means that the compound falls within the definition of two or more polymerizable compounds having the same polymerization mechanism described above.

[0019] The same polymerization mechanism in two or more polymerizable compounds may be any as long as the propagation active species have the same polymerization mechanism, and examples thereof include radical polymerization, cationic polymerization, and anionic polymerization, with radical polymerization or cationic polymerization being preferred, and radical polymerization being more preferred. The same polymerizable group possessed by two or more polymerizable compounds may be, for example, a radical polymerizable group, a cationic polymerizable group, and an anionic polymerizable group. The polymerizable compound preferably has a radical polymerizable group or a cationic polymerizable group as the same polymerizable group, and more preferably has a radical polymerizable group. That is, the polymerizable compound may be any of a radical polymerizable compound, a cationic polymerizable compound, and an anionic polymerizable compound, and is preferably a radical polymerizable compound or a cationic polymerizable compound, and more preferably a radical polymerizable compound.

[0020] The number of polymerizable groups possessed by the polymerizable compound is not particularly limited, and the polymerizable compound may be a monofunctional polymerizable compound having one polymerizable group, or a polyfunctional polymerizable compound having two or more polymerizable groups. The number of polymerizable groups possessed by the polyfunctional polymerizable compound is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. Furthermore, the polymerizable compound may have a polymerizable group having the same polymerization mechanism as the other polymerizable compounds contained in the composition, as well as a polymerizable group having a different polymerization mechanism from the other polymerizable compounds. It is preferable that the polymerizable compound only have a polymerizable group having the same polymerization mechanism as the other polymerizable compounds contained in the composition.

[0021] Examples of the radical polymerizable compound include polymerizable compounds (ethylenically unsaturated compounds) having at least one ethylenically unsaturated group such as a vinyl group, a (meth)acryloyl group, a styryl group, and a maleimide group. Examples of the polymerizable compound having a (meth)acryloyl group (hereinafter also referred to as "(meth)acrylate") include (meth)acrylates having a hydrocarbon group or an alkylene oxide adduct of a hydrocarbon group (preferably phenol ethylene oxide-modified (meth)acrylates having a phenylphenol group or a phenoxy group), urethane (meth)acrylates having a urethane structure, epoxy (meth)acrylates having an epoxy structure, and (meth)acrylates having a heterocyclic structure such as fluorene.

[0022] The (meth)acrylate having a hydrocarbon group or an alkylene oxide adduct of a hydrocarbon group may be either a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate, with a monofunctional (meth)acrylate being preferred.

[0023] Examples of the hydrocarbon group include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. Examples of the aliphatic hydrocarbon group include linear or branched alkyl groups having 1 to 40 carbon atoms, and linear or branched alkenyl groups having 3 to 40 carbon atoms. Examples of the alicyclic hydrocarbon group include monocyclic or polycyclic cycloalkyl groups having 3 to 30 carbon atoms. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a biphenyl group. Examples of the alkylene oxide adducts of the hydrocarbon group include ethylene oxide adducts, propylene oxide adducts, and butylene oxide adducts of the above hydrocarbon groups.

[0024] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, n-amyl (meth)acrylate, i-amyl (meth)acrylate, t-amyl (meth)acrylate, neopentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, tetracosyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, cyclohexyl (meth)acrylate, menthyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, and benzyl (meth)acrylate.

[0025] Examples of polyfunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl (meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate. acrylate, dipentaerythritol hexa(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalic acid neopen glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate.

[0026] As the (meth)acrylate having a hydrocarbon group or an alkylene oxide adduct of a hydrocarbon group, a (meth)acrylate in which the hydrocarbon group is an alicyclic hydrocarbon group or an aromatic hydrocarbon group is preferred, and a (meth)acrylate in which the hydrocarbon group is an aromatic hydrocarbon group is more preferred. Among these, a phenol ethylene oxide-modified (meth)acrylate having a phenylphenol group or a phenoxy group is even more preferred, and an ethoxylated-o-phenylphenol acrylate represented by the following formula (1) is particularly preferred. In formula (1), n ​​represents an integer of 1 to 5.

[0027]

[0028] A urethane (meth)acrylate having a urethane structure is a compound having a urethane structure (urethane bond) and at least one (meth)acryloyl group in the molecule. Examples of the urethane (meth)acrylate include known urethane (meth)acrylates such as aliphatic urethane (meth)acrylates and aromatic urethane (meth)acrylates. The urethane (meth)acrylate is preferably a multifunctional urethane (meth)acrylate having two or more (meth)acryloyl groups in the molecule. The multifunctional urethane (meth)acrylate may have only one of an acryloyl group or a methacryloyl group, or may have both an acryloyl group and a methacryloyl group.

[0029] The number of (meth)acryloyl groups contained in the polyfunctional urethane (meth)acrylate molecule may be 2 or more, preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. The weight average molecular weight (Mw) of the polyfunctional urethane (meth)acrylate is preferably 500 to 10,000, more preferably 500 to 7,000, and even more preferably 500 to 5,000.

[0030] The polyfunctional urethane (meth)acrylate can be produced by a known method, for example, by reacting a polyol (X), a polyisocyanate (Y), and a hydroxy group-containing (meth)acrylate (Z), or by reacting a polyisocyanate (Y) with a hydroxy group-containing (meth)acrylate (Z).

[0031] The polyol (X) is a compound having two or more hydroxy groups in the molecule. The polyol (X) may be used alone or in combination of two or more. Examples of the polyol (X) include ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, polyoxy C2-4 alkylene glycols (polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, etc.), bisphenol A and its alkylene oxide adduct, bisphenol F and its alkylene oxide adduct, hydrogenated bisphenol A and its alkylene oxide adduct, hydrogenated bisphenol F and its alkylene oxide adduct, cyclohexanediol, Examples of the polyol include diols such as cyclohexanedimethanol, tricyclodecanedimethanol, isosorbide, xylene glycol, polyester diol, polyether diol, and polycarbonate diol; and polyols having three or more hydroxy groups in the molecule, such as glycerin, 1,1,1-tris(hydroxymethyl)propane, D-sorbitol, xylitol, D-mannitol, D-mannite, diglycerin, polyglycerin, trimethylolethane, trimethylolpropane, pentaerythritol, polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, epoxy polyol, natural oil polyol, silicone polyol, fluorine polyol, and polyolefin polyol.

[0032] The polyisocyanate (Y) is a compound having two or more isocyanate groups in the molecule. The polyisocyanate (Y) may be used alone or in combination of two or more. Examples of the polyisocyanate (Y) include diisocyanates such as 1,6-hexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; and diisocyanate trimers such as biurets, adducts, and nurate compounds (nurate compounds of 1,6-hexamethylene diisocyanate, nurate compounds of 2,6-hexamethylene diisocyanate, etc.).

[0033] The hydroxy group-containing (meth)acrylate (Z) is a compound having one or more (more preferably one) hydroxy groups and one or more (more preferably one) (meth)acryloyl groups in the molecule. The hydroxy group-containing (meth)acrylate (Z) may be used alone or in combination of two or more. Examples of the hydroxy group-containing (meth)acrylate (Z) include epoxy (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, cyclohexanedimethanol (meth)acrylate, and bisphenol A diglycidyl diacrylate, as well as hydrogenated versions of these.

[0034] As a method for producing a polyfunctional urethane (meth)acrylate by reacting the polyol (X), polyisocyanate (Y), and hydroxy group-containing (meth)acrylate (Z), known methods such as those described in JP-A-7-157531, JP-A-2000-95837, JP-A-2002-145936, and JP-A-2011-52227 can be applied. The contents of the above publications are incorporated herein by reference.

[0035] Among the polyfunctional urethane (meth)acrylates, those containing at least a structural unit derived from a polyoxy C2-4 alkylene glycol (polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, etc.) as a structural unit derived from the polyol (X) are preferred. Examples of such polyfunctional urethane (meth)acrylates include those sold under the trade names "EBECRYL 230" and "EBECRYL 270."

[0036] Commercially available polyfunctional urethane (meth)acrylates can also be used. Commercially available polyfunctional urethane (meth)acrylate products include, for example, those under the trade names "EBECRYL 210", "EBECRYL 215", "EBECRYL 6202", "EBECRYL 230", "EBECRYL 244", "EBECRYL 245", "EBECRYL 270", "EBECRYL 280 / 15IB", "EBECRYL 2002", "EBECRYL 8307", "EBECRYL 8411", "EBECRYL 8804", "EBECRYL 8807", "EBECRYL 9227EA", "KRM7735", "EBECRYL 284", "EBECRYL 285", "EBECRYL 4835", and "EBECRYL bifunctional urethane (meth)acrylates (urethane di(meth)acrylates) such as "EBECRYL 4858", "EBECRYL 4883", "EBECRYL 6700", "EBECRYL 8402", and "EBECRYL 9270" (all manufactured by Daicel-Allnex Co., Ltd.), trade names "UX-2201" and "UX-8101" (all manufactured by Nippon Kayaku Co., Ltd.), and trade names "UF-8001", "UF-8003", "UX-6101", and "UX-8101" (all manufactured by Kyoeisha Chemical Co., Ltd.); Examples of suitable urethane (meth)acrylates include trifunctional urethane (meth)acrylates such as "EBECRYL 9260," "KRM8296," "EBECRYL 294 / 25 HD," "EBECRYL 4820," "EBECRYL 8311," and "EBECRYL 8701" (all manufactured by Daicel-Allnex Co., Ltd.); and tetrafunctional or higher urethane (meth)acrylates such as trade names "EBECRYL 220," "KRM8200," "KRM8200AE," "EBECRYL 5129," "EBECRYL 8210," "EBECRYL 8301," "KRM8452," "EBECRYL 8405," "EBECRYL 1290k," and "KRM7804" (all manufactured by Daicel-Allnex Co., Ltd.).

[0037] Examples of the cationically polymerizable compound include polymerizable compounds having a cationically polymerizable group such as an epoxy group and an oxetane group. When the two or more polymerizable compounds contained in the composition are cationically polymerizable compounds (when the polymerization mechanism of the two or more polymerizable compounds is cationic polymerization), the composition preferably contains a curing agent (e.g., polyol, acid anhydride, polyamine, etc.) that polymerizes with the cationically polymerizable compound to form a cured product such as an epoxy resin or a urethane resin.

[0038] The polymerizable compound can be appropriately selected in consideration of the characteristics of the self-forming optical waveguide to be formed, the viscosity of the polymerizable compound, the compatibility between the polymerizable compounds, and the reactivity of the polymerizable compound. Among these, the present composition preferably contains two or more (meth)acrylates as polymerizable compounds, more preferably a (meth)acrylate having at least one hydrocarbon group or an alkylene oxide adduct of a hydrocarbon group, and at least one urethane (meth)acrylate, and even more preferably a monofunctional (meth)acrylate having at least one hydrocarbon group or an alkylene oxide adduct of a hydrocarbon group, and at least one polyfunctional urethane (meth)acrylate. Preferred aspects of the monofunctional (meth)acrylate and polyfunctional urethane (meth)acrylate are as described above.

[0039] In addition, it is preferable that none of the polymerizable compounds contain a thio(meth)acrylate group, since the refractive index of the polymerizable compound tends to be smaller.In addition, in view of the above, it is preferable that none of the polymerizable compounds contain a sulfur atom or a halogen atom.

[0040] The polymerizable compound may be any of a polymer, an oligomer, and a low-molecular-weight compound. The molecular weight of the polymerizable compound is not particularly limited, but is preferably 100 to 50,000. When the polymerizable compound has a molecular weight distribution, it is preferable that the weight-average molecular weight (Mw) of the polymerizable compound is within the above range. In terms of improving the handleability of the present composition, the viscosity of the polymerizable compound at 25°C is preferably 500 to 100,000 mPa·s, and more preferably 1,000 to 20,000 mPa·s. In this specification, the viscosity of compounds, compositions, etc. is the viscosity measured when measuring an object at 25°C using an E-type viscometer (for example, the "RE-85" manufactured by Toki Sangyo Co., Ltd.).

[0041] The two or more polymerizable compounds contained in the composition preferably include at least a combination of two polymerizable compounds having different refractive indices. In other words, the composition preferably includes at least a first polymerizable compound and a second polymerizable compound, and the refractive index of the first polymerizable compound is different from the refractive index of the second polymerizable compound. By selecting two or more polymerizable compounds contained in the composition so as to include a combination of polymerizable compounds having different refractive indices, a self-written optical waveguide consisting of a core portion having a high refractive index and a solid clad portion arranged around the core portion and having a low refractive index can be more easily produced using the composition.

[0042] In the above-mentioned combination of two polymerizable compounds with different refractive indices, the difference in refractive index between one polymerizable compound and the other polymerizable compound is preferably 0.05 or more, more preferably 0.1 or more. The upper limit of the difference in refractive index is not particularly limited and may be, for example, 0.5 or less. In this specification, the refractive index of a compound, member, etc. means the refractive index at the wavelength of light guided by the optical waveguide formed using the present composition, unless otherwise specified. The refractive index of a polymerizable compound means the refractive index of a cured product obtained by curing the polymerizable compound alone. The refractive index of the polymerizable compound in question is measured using an Abbe refractometer.

[0043] The refractive index of the polymerizable compound can be adjusted by the structure of the polymerizable compound. More specifically, when the polymerizable compound has a structure that contains fewer fused ring structures and no sulfur molecules, the refractive index of the polymerizable compound tends to be smaller.

[0044] The two or more polymerizable compounds contained in the composition preferably include at least a combination of two polymerizable compounds having different reactivities. In other words, the composition preferably includes at least a first polymerizable compound and a second polymerizable compound, and the reactivity of the first polymerizable compound is different from the reactivity of the second polymerizable compound. When the composition contains a combination of two polymerizable compounds having different reactivities, the polymerizable compound with higher reactivity aggregates during core formation, making it easier to form the core, and as a result, it becomes easier to form a self-written optical waveguide using the composition.

[0045] An example of a combination of two polymerizable compounds with different reactivities is a combination of two polymerizable compounds with different numbers of polymerizable groups per molecule that have the same polymerization mechanism. It is presumed that the fewer polymerizable groups a polymerizable compound has per molecule, the higher its reactivity tends to be. That is, the two or more polymerizable compounds contained in the composition preferably include at least a combination of two polymerizable compounds with different numbers of polymerizable groups per molecule that have the same polymerization mechanism. In a combination of two polymerizable compounds with different numbers of polymerizable groups per molecule, the number of polymerizable groups in each polymerizable compound is not particularly limited, but one of the two polymerizable compounds may have, for example, 1 to 3 polymerizable groups, preferably 1 or 2, and more preferably 1, and the other may have, for example, 2 to 5 polymerizable groups, preferably 2 or 3, and more preferably 2.

[0046] Another example of a combination of two polymerizable compounds with different reactivities is a combination of two polymerizable compounds with different molecular weights. It is presumed that the higher the molecular weight, the more difficult the diffusion within the composition and the lower the reactivity. In a combination of two polymerizable compounds with different molecular weights, the difference in molecular weight between the two polymerizable compounds is not particularly limited, but is preferably 100 or more, more preferably 200 or more, and even more preferably 500 or more. The upper limit of the molecular weight difference is not particularly limited, and may be, for example, 100,000 or less. In a combination of two polymerizable compounds with different molecular weights, the molecular weight of each polymerizable compound is not particularly limited, but the molecular weight of one polymerizable compound is, for example, 100 to 1,000, preferably 150 to 800, and more preferably 200 to 500, and the molecular weight of the other polymerizable compound is, for example, 500 to 10,000, preferably 800 to 5,000, and more preferably 1,000 to 3,000.

[0047] Furthermore, it is more preferable that the two or more polymerizable compounds contained in the composition include at least a combination of two polymerizable compounds having different refractive indices and different reactivities. In other words, it is more preferable that the composition includes at least a first polymerizable compound and a second polymerizable compound, and that the refractive index of the first polymerizable compound is different from the refractive index of the second polymerizable compound and that the reactivity of the first polymerizable compound is different from the reactivity of the second polymerizable compound. For example, when a self-written optical waveguide is designed in which the refractive index of the core portion is higher than the refractive index of the cladding portion, a combination of two polymerizable compounds is used in which the refractive index of the more reactive polymerizable compound is higher than the refractive index of the less reactive polymerizable compound. As a result, during core formation, the highly reactive polymerizable compound gathers to form the core portion, and then the less reactive polymerizable compound polymerizes around the core portion to form the cladding portion, thereby forming a self-written optical waveguide having a core portion with a high refractive index and a cladding portion with a low refractive index. In this way, by including a combination of two or more polymerizable compounds having different reactivities and different refractive indices, it becomes easier to form a self-written optical waveguide in which the refractive index of the core portion and the refractive index of the clad portion differ.

[0048] In the combination of the two polymerizable compounds, the refractive index of the more reactive polymerizable compound is preferably higher than that of the less reactive polymerizable compound, since this facilitates the formation of an all-solid-state self-forming optical waveguide having a core with a high refractive index and a clad with a low refractive index. In this case, the difference in refractive index between the two polymerizable compounds is more preferably within the above-mentioned range. Furthermore, the difference in the number of functional groups and the difference in molecular weight between the two polymerizable compounds are more preferably within the above-mentioned ranges.

[0049] The higher the compatibility of the two or more polymerizable compounds, the less likely it is that a fine phase separation structure, which is one of the causes of scattering (light loss) when light is guided in a self-written optical waveguide, will occur. When the present composition contains two polymerizable compounds, the Hansen solubility parameter distance (ΔHSP) of the two polymerizable compounds is 7 MPa or less. ０．５ Preferably, 4 MPa or less ０．５ The lower limit is not particularly limited, and 0 MPa or less is more preferable. ０．５ When the present composition contains three or more polymerizable compounds, it is preferable that the ΔHSP of two polymerizable compounds selected from the three or more polymerizable compounds each falls within the above range.

[0050] Hansen solubility parameters (HSP) are values ​​that divide the solubility of a substance into three components (dispersion term δD, polar term δP, and hydrogen bond term δH) and represent them in a three-dimensional space. The ΔHSP between a polymerizable compound and a special compound is calculated using the following formula: ΔHSP = (4 x (dDa - dDb) ２ +(dPa-dPb) ２ +(dHa-dHb) ２ ) ０．５In the above formula, dDa, dPa, and dHa respectively represent the dispersion term, polarization term, and hydrogen bond term of one of the two polymerizable compounds, and dDb, dPb, and dHb represent the dispersion term, polarization term, and hydrogen bond term of the other polymerizable compound. The definition and calculation method of the Hansen solubility parameter for each compound are described in Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007). Furthermore, by using the computer software Hansen Solubility Parameters in Practice (HSPiP), the Hansen solubility parameter can be easily estimated from the chemical structure of a compound for which literature values ​​are unknown. In this specification, the Hansen solubility parameters are calculated using the Y-MB method using HSPiP (ver. 5).

[0051] In the present composition, the content of two or more polymerizable compounds is appropriately selected depending on the structure of the self-forming optical waveguide to be formed. The content of one polymerizable compound may be, for example, 1 to 99% by mass, preferably 5 to 95% by mass, based on the total mass of the present composition. Furthermore, the total content of the two or more polymerizable compounds in the entire present composition may be, for example, 1 to 99% by mass, preferably 5 to 95% by mass, based on the total mass of the present composition.

[0052] (Polymerization initiator) The present composition preferably contains a polymerization initiator. The polymerization initiator contained in the present composition is preferably a photopolymerization initiator, and more preferably a photopolymerization initiator that generates radicals or acids upon irradiation with ultraviolet or visible light. Various photosensitive compounds can be used as the photopolymerization initiator. The type of photopolymerization initiator is appropriately selected depending on the type of polymerizable compound contained in the present composition and the wavelength of light irradiated when forming the optical waveguide.

[0053] Examples of the photopolymerization initiator include acylphosphine oxide initiators, oxyphenylacetic acid ester initiators, benzoylformic acid initiators, and hydroxyphenyl ketone initiators. More specific examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-1-propanone, 2,2-dimethoxy-2-phenylacetophenone, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester, oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), and 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester.

[0054] The polymerization initiator may be used alone or in combination of two or more types, but the process can be simplified by curing two or more different polymerizable compounds at the same wavelength. When the composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.1 to 10 mass% and more preferably 0.2 to 5 mass% relative to the total mass of the composition. When the content of the polymerization initiator is equal to or greater than the above-mentioned lower limit, the reactivity during self-formation of the optical waveguide is improved, and when the content of the polymerization initiator is equal to or less than the above-mentioned upper limit, coloration of the optical waveguide is further suppressed.

[0055] The viscosity of the present composition at 25°C is preferably 500 to 100,000 mPa·s, and more preferably 1,000 to 20,000 mPa·s, in terms of better handleability. The viscosity of the present composition can be adjusted by selecting the type of polymerizable compound.

[0056] The method for preparing the composition is not particularly limited, and the composition can be prepared, for example, by mixing a polymerizable compound, a polymerization initiator, and various additives that are added as needed.

[0057] As described above, the present composition is a composition used for producing a self-written optical waveguide, and by using the present composition, a self-written optical waveguide with high connection efficiency can be formed.

[0058] [Method for manufacturing a self-written optical waveguide] A self-written optical waveguide can be formed, for example, by preparing an optical element and the present composition placed close to the optical element, and then curing the composition by irradiating it with light from the optical element. Specific embodiments of the method for manufacturing a self-written optical waveguide will be described below.

[0059] First Embodiment A method for manufacturing a self-forming optical waveguide according to a first embodiment includes the following steps: a preparation step of preparing an optical element and a self-forming optical waveguide composition disposed in proximity to the optical element, a core portion-forming step of irradiating light from the optical element to cure the self-forming optical waveguide composition to form a core portion, and a cladding portion-forming step of exposing uncured components in the self-forming optical waveguide composition to form a cladding portion, thereby forming a self-forming optical waveguide including a core portion and a cladding portion. Here, in this embodiment, a self-forming optical waveguide composition containing two or more polymerizable compounds and a photopolymerization initiator is used.

[0060] This embodiment will be described in more detail below with reference to the drawings. FIGS. 1A to 1C are schematic diagrams illustrating a method for manufacturing a self-written optical waveguide according to this embodiment. The self-written optical waveguide manufacturing apparatus 100 shown in FIGS. 1A to 1C includes a transparent container 10, an optical fiber 20 (optical element), and a lamp 30 (only in FIG. 1C). A self-written optical waveguide composition (composition 1) is held in the transparent container 10. In the following specific example, composition 1 includes a polymerizable compound A having a relatively high reactivity and a relatively high refractive index, and a polymerizable compound B having a relatively low reactivity and a relatively low refractive index.

[0061] 1A , in the preparation step, one end 20A of the optical fiber 20 is brought into contact with the composition 1. In the preparation step, the composition 1 may be filled into the transparent container 10, and then the optical fiber 20 may be placed so that the end 20A is in contact with the composition 1, or the optical fiber 20 may be placed so that the end 20A is located within the transparent container 10, and then the composition 1 may be filled into the transparent container 10.

[0062] In the core portion formation process, irradiation light L (e.g., UV light) transmitted from a light source (not shown) through an optical fiber 20 and emitted from an end portion 20A is irradiated onto the composition 1, selectively polymerizing (curing) a large amount of the polymerizable compound A contained in the composition 1, which has high reactivity and a high refractive index. As a result, as shown in FIG. 1B , an optical waveguide (core portion 2) is gradually formed within the composition 1 from the end portion 20A along the optical axis of the irradiation light L at the end portion 20A. At this time, because the refractive index of the formed core portion 2 is higher than the refractive index of the uncured polymerizable compound B, the light irradiated from the optical fiber 20 is concentrated on the tip of the core portion 2, and as a result, the core portion 2 gradually extends linearly from the end portion 20A. Meanwhile, as the polymerization of the polymerizable compound A and the formation of the core portion 2 progress, the uncured polymerizable compound B, which has fluidity, is expelled from the core portion 2. Eventually, a core portion 2 is formed within the composition 1 so as to penetrate from the end portion 20A to the end face on the opposite side, and the formed core portion 2 is surrounded by the uncured composition 1.

[0063] 1C , in the cladding portion forming step, a lamp 30 (the same light source as in the core portion forming step) is used to irradiate the composition 1 from around it with light (e.g., UV light) that polymerizes (cures) the composition 1, thereby exposing the composition 1 and polymerizing (curing) the uncured polymerizable compound B. As a result, a cladding portion 3 is formed around the core portion 2, and an all-solid-state self-written optical waveguide 4 consisting of the core portion 2 and the cladding portion 3 is formed.

[0064] Second Embodiment A second embodiment of the method for manufacturing a self-forming optical waveguide will be described with reference to the drawings. Regarding the second embodiment, a description of configurations and operations common to the first embodiment will be omitted. The method for manufacturing a self-forming optical waveguide according to the second embodiment includes a preparation step of preparing a first optical element, a second optical element, and a self-forming optical waveguide composition disposed between the first and second optical elements; a core portion formation step of irradiating light from at least one of the first and second optical elements to cure the self-forming optical waveguide composition to form a core portion; and a clad portion formation step of exposing the uncured components in the self-forming optical waveguide composition to form a clad portion, thereby forming a self-forming optical waveguide including a core portion and a clad portion. This embodiment also uses a self-forming optical waveguide composition containing polymerizable compounds A and B and a photopolymerization initiator.

[0065] 2A to 2D are schematic diagrams illustrating a method for manufacturing a self-written optical waveguide according to this embodiment. The self-written optical waveguide manufacturing apparatus 110 shown in Figures 2A to 2D includes a transparent container 10, a first optical fiber 21, a second optical fiber 22, and a lamp 30.

[0066] 2A , in the preparation step, one end 21A of the first optical fiber 21 and one end 22A of the second optical fiber 22 are brought into contact with the composition 1. In the preparation step, the composition 1 may be filled into the transparent container 10, and then the first optical fiber 21 and the second optical fiber 22 may be placed so that the end 21A and the end 22A are in contact with the composition 1, or the first optical fiber 21 and the second optical fiber 22 may be placed so that the end 20A is located within the transparent container 10, and then the composition 1 may be filled into the transparent container 10.

[0067] In the core portion forming step of this embodiment, the composition 1 is irradiated with irradiation light from at least one of the first optical fiber 21 and the second optical fiber 22 to selectively polymerize (cure) a large amount of the polymerizable compound A, which is highly reactive and has a high refractive index and is contained in the composition 1, thereby forming an optical waveguide (core portion 2) inside the composition 1. That is, the irradiation light for forming the core portion 2 may be emitted from only one of the first optical fiber 21 and the second optical fiber 22, or may be emitted from both the first optical fiber 21 and the second optical fiber 22.

[0068] FIG. 2B shows an example of forming a core portion 2 by irradiating the composition 1 with irradiation light L1 only from the first optical fiber 21. In this example, irradiation light L1 transmitted from a light source (not shown) through the first optical fiber 21 is irradiated onto the composition 1 from the end 21A, selectively polymerizing (curing) a large amount of the polymerizable compound A contained in the composition 1, which has high reactivity and a high refractive index. As a result, the core portion 2 is formed along the optical axis of the irradiation light L1 at the end 21A. Eventually, the core portion 2 is formed inside the composition 1, penetrating from the end 21A to the end 22A located on the opposite side, and the first optical fiber 21 and the second optical fiber 22 are optically connected by the core portion 2. In addition, the formed core portion 2 is surrounded by uncured composition 1. Next, as in the first embodiment, the composition 1 is exposed to light using a lamp 30 (the same light source as in the core portion formation process) to polymerize (cure) the uncured polymerizable compound B, thereby performing a cladding portion formation process (see FIG. 1C ). As a result, the cladding 3 is formed around the core 2, and an all-solid-state self-written optical waveguide 4 consisting of the core 2 and the cladding 3 is formed.

[0069] 2C and 2D show an example in which the composition 1 is irradiated with irradiation light L from both the first optical fiber 21 and the second optical fiber 22 to form a core portion 2. In this example, as shown in the figures, the composition 1 is irradiated with irradiation light L1 from the end 21A of the first optical fiber 21, and with irradiation light L2 from the end 22A of the second optical fiber 22. As a result, a core portion 2 is formed from both the end 21A and the end 22A along the optical axes of the irradiation light L1 and L2. At this time, as shown in FIG. 2C , the extending directions of the two core portions 2 may be misaligned. Even in this case, as the tips of the two core portions 2 approach each other, the irradiation light L1 and L2 from the respective tips overlap, creating a region where the light intensity is increased, and the composition 1 is preferentially cured in that region. As a result, the two core portions 2 are connected to form a single core portion 2 that optically connects the end 21A of the first optical fiber 21 and the end 22A of the second optical fiber 22. Next, as in the first embodiment, a cladding formation step is performed in which the composition 1 is exposed to light using a lamp 30 (the same light source as in the core formation step) to polymerize (cure) the uncured polymerizable compound B. As a result, a cladding 3 is formed around the core 2, and an all-solid-state self-written optical waveguide 4 consisting of the core 2 and the cladding 3 is formed.

[0070] The wavelength of the light irradiated to the composition in the core portion-forming step is not particularly limited and is appropriately selected depending on the composition of the composition containing the photopolymerization initiator. Examples of the wavelength of the light irradiated in the core portion-forming step include UV light, visible light, and IR light. The wavelength of the light irradiated to the uncured component of the composition in the cladding portion-forming step is not particularly limited and is appropriately selected depending on the composition of the composition containing the polymerizable compound and the photopolymerization initiator, but it is preferable to use the same light source as in the core portion-forming step. Examples of the wavelength of the light irradiated in the cladding portion-forming step include UV light, visible light, and IR light. Furthermore, it is preferable that the wavelength of the light irradiated in the core portion-forming step and the wavelength of the light irradiated in the cladding portion-forming step are the same.

[0071] In the method for producing a self-written optical waveguide, the optical element used to irradiate the composition with light can be any optical component that can be placed in proximity to the composition and that can emit light. Examples of such optical elements include the above-mentioned optical fiber, as well as optical waveguides, semiconductor lasers, light-emitting diodes, photodiodes, and lenses.

[0072] Furthermore, the self-written optical waveguide produced using the present composition may have a branched structure. For example, during or after the core formation step, the present composition may be irradiated with light from a direction intersecting the direction in which the cores extend, thereby connecting the cores to each other near the positions where the irradiated light intersects, thereby forming a core having a branched structure.

[0073] [Self-Writing Optical Waveguide] The self-writing optical waveguide according to the present invention is a self-writing optical waveguide manufactured using the present composition. By using the present composition, a self-writing optical waveguide with high connection efficiency can be obtained. The self-writing optical waveguide is preferably an all-solid-state self-writing optical waveguide including a core portion containing a larger amount of a cured polymerizable compound having a relatively high reactivity and a relatively high refractive index, and a clad portion containing a larger amount of a cured polymerizable compound having a relatively low reactivity and a relatively low refractive index. The method for manufacturing a self-writing optical waveguide has already been described, but the self-writing optical waveguide according to the present invention may be manufactured by a manufacturing method other than the above-described method as long as it is manufactured using the present composition.

[0074] In the self-written optical waveguide including the core and clad portions, the difference in refractive index between the core and clad portions is preferably 0.005 or more, more preferably 0.01 or more, and even more preferably 0.02 or more. The upper limit is not particularly limited, and may be 0.5 or less.

[0075] The optical waveguide according to the present invention is formed by self-forming (self-organization) and has high connection efficiency, and is therefore useful as an optical waveguide for various optical devices, and is particularly useful as an optical coupler for connecting multiple optical elements.

[0076] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0077] Example 1 Preparation of a composition for self-written optical waveguide A-LEN-10 (ethoxylated-o-phenylphenol acrylate manufactured by Shin-Nakamura Chemical Co., Ltd.), EBECRYL (registered trademark) 270 (urethane diacrylate manufactured by Daicel-Allnex Corporation), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide as a photopolymerization initiator were mixed in a mass ratio of 50:50:1 to obtain composition X-1.

[0078] Examples 2 to 4 Compositions X-2 and X-3 were prepared according to the procedure described in Example 1, except that the compound described in the Monomer B column of Table 1 was used instead of EBECRYL270. Composition X-4 was prepared according to the procedure described in Example 1, except that the compound described in the Monomer A column of Table 1 was used instead of A-LEN-10. The compounds used in the preparation of Compositions X-2 to X-4 are as follows: "EBECRYL230": urethane diacrylate manufactured by Daicel-Allnex Corporation. "EBECRYL8402": urethane diacrylate manufactured by Daicel-Allnex Corporation. "NMT-A": phenylmethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd. Table 1 shows the physical properties of the compounds used as Monomer A or Monomer B.

[0079]

[0080] [Measurement of Viscosity] The viscosity at 25°C of Compositions X-1 to X-4 and the components other than the photopolymerization initiator used in the preparation of Compositions X-1 to X-4 in each example was measured using an E-type viscometer ("RE-85" manufactured by Toki Sangyo Co., Ltd.) The measurement results are shown in Table 1 above.

[0081] [Measurement of Refractive Index] The refractive index nd25 of each compound was measured using an Abbe refractometer. The measurement results are shown in Table 1 above.

[0082] [Self-Written Optical Waveguide Fabrication Test] According to the following test method, an attempt was made to fabricate a self-written optical waveguide using each of compositions X-1 to X-4. The test method using composition X-1 as a representative example is described below. A glass tube with an inner diameter of 2.8 mm was filled with composition X-1 in an amount that would result in a length of 2 mm. An optical fiber with a core diameter of 50 μm was inserted into the tube, and the optical fiber was positioned so that the exit port at one end was in contact with composition X-1. UV light was irradiated for 30 seconds through the optical fiber from a light source (xenon UV lamp) located at the other end of the optical fiber. The illuminance of the UV light at the exit port of the optical fiber was 10 μW / cm ２ Thereafter, UV light (light source: metal halide lamp) was irradiated from the side of the cylinder with 200 mW / cm 2 onto the composition X-1 filled in the cylinder. ２ The sample was irradiated with 1000 kJ / min for 1 minute.

[0083] [Evaluation] [Formation of self-written optical waveguide] In the above-mentioned production test, after irradiation with UV light through the optical fiber was completed, each composition was observed with an optical microscope to confirm the presence or absence of an optical waveguide. Based on the observation results, examples in which the presence of an optical waveguide was confirmed were evaluated as "A", and examples in which the presence of an optical waveguide was not confirmed were evaluated as "B". Note that, as a result of the observation, if the composition was found to be flowing and no clear optical waveguide structure was observed, it was evaluated as "B".

[0084] [Evaluation of Fully Solidified Self-Written Optical Waveguides] In the above fabrication test, the optical waveguides formed by irradiation with UV light through the optical fiber were observed using an optical microscope during and after the UV light irradiation from the side of the tube to confirm whether the structure of the optical waveguide was maintained. Based on the observation results, examples in which the structure of the optical waveguide was maintained even after the UV light irradiation from the side of the tube was completed were evaluated as "A," and examples in which the structure of the optical waveguide was lost and not maintained due to flow of the composition or other factors before the UV light irradiation from the side of the tube was completed were evaluated as "B." In examples rated as A, it can be evaluated that a solid cladding portion was formed around the optical waveguide (core portion), and an all-solid self-written optical waveguide was produced that maintained the structure of the optical waveguide.

[0085] [Evaluation of optical waveguide performance] After the above-mentioned fabrication test was completed, red laser light emitted from the laser light source was output from the light irradiation port through the optical fiber and guided inside the composition filled in the tube. The end face of the composition opposite the light irradiation port was observed with an optical microscope, and the performance of each composition as an optical waveguide was evaluated based on the observation results and the following criteria: 3: Strong color development of the guided laser light was observed at the end face on the opposite side. 2: Weak color development of the guided laser light was observed at the end face on the opposite side. 1: No color development of the guided laser light was observed at the end face on the opposite side.

[0086] Table 2 shows the evaluation results of the self-written optical waveguide fabrication test carried out using the compositions of each example.

[0087]

[0088] From the results shown in Table 2, it was confirmed that by using the self-forming optical waveguide composition of the present invention, it is possible to easily form an all-solid self-forming optical waveguide in which the core and clad are both solid, without removing the uncured components around the core after the core is formed.

[0089] REFERENCE SIGNS LIST 1 composition 2 core portion 3 cladding portion 4 self-written optical waveguide 10 transparent container 20A, 21A, 22A end portion 20 optical fiber 21 first optical fiber 22 second optical fiber 30 lamp 100, 110 manufacturing device L, L1, L2 irradiation light

Claims

1. A composition for a self-written optical waveguide, comprising two or more polymerizable compounds, the polymerization mechanisms of which are the same for the two or more polymerizable compounds.

2. The self-forming optical waveguide composition according to claim 1, wherein the polymerization mechanism is at least one selected from radical polymerization, cationic polymerization, and anionic polymerization.

3. The self-written optical waveguide composition according to claim 1 or 2, wherein the two or more polymerizable compounds include at least a combination of two polymerizable compounds having a difference in refractive index of 0.05 or more.

4. A composition for a self-written optical waveguide according to claim 1 or 2, wherein the two or more polymerizable compounds include at least a combination of two polymerizable compounds having the same polymerization mechanism but different numbers of polymerizable groups contained in one molecule.

5. The self-forming optical waveguide composition according to claim 1 or 2, wherein none of the two or more polymerizable compounds contains a thio(meth)acrylate group.

6. The self-writing optical waveguide composition according to claim 1 or 2, wherein the viscosity of the self-writing optical waveguide composition at 25° C. is 500 to 100,000 mPa·s.

7. A self-written optical waveguide manufactured using the composition for a self-written optical waveguide according to claim 1 or 2.

8. A method for manufacturing a self-forming optical waveguide using the self-forming optical waveguide composition according to claim 1 or 2, comprising the steps of: preparing a first optical element, a second optical element, and the self-forming optical waveguide composition disposed between the first optical element and the second optical element; irradiating light from at least one of the first optical element and the second optical element to cure the self-forming optical waveguide composition and form a core portion; and exposing uncured components in the self-forming optical waveguide composition to form a clad portion, thereby forming a self-forming optical waveguide comprising the core portion and the clad portion.

Images