Abstract: An optical-electrical composite flexible circuit substrate having sufficiently high bending resistance is provided. An optical-electrical composite flexible circuit substrate includes: an optical circuit that includes a core portion and a cladding layer that covers the core portion; and an electrical circuit, with the optical circuit and the electrical circuit being disposed at a position that includes a neutral surface when the optical-electrical composite flexible circuit substrate is bent, or at a position near the neutral surface. Alternatively, the optical-electrical composite flexible circuit substrate may include an optical circuit that includes a core portion and a cladding layer that covers the core portion; and a substrate that includes an electrical circuit, with the substrate and the optical circuit being laminated so that the electrical circuit is disposed on a side closer to the optical circuit.

Abstract: Provided are a resin composition which offers both high transparency and a low linear expansion coefficient and can be used as a material for a dry film, and also a dry film obtained from this composition, an optical waveguide, and a photoelectric composite wiring board. The resin composition for an optical waveguide includes: (A) an epoxy resin constituted by a solid epoxy resin with one or less hydroxyl group in a molecule, and a liquid epoxy resin with one or less hydroxyl group in a molecule; (B) a curing agent with one or less hydroxyl group in a molecule; and (C) a nanosize silica sol, and contains no compound including two or more hydroxyl groups in a molecule as a resin component.

Abstract: In order to provide a method of efficiently manufacturing an optical waveguide core having an endface inclined at a predetermined angle, the following method of manufacturing an optical waveguide core is employed.

Abstract: In order to provide a method of manufacturing an optical waveguide, which enables the formation of a smooth mirror face, the following method of manufacturing an optical waveguide having a mirror face is used. The method includes: a photocurable resin sheet laminating step of laminating an uncured photocurable resin sheet for forming a core on a surface of a first cladding layer that has been formed on a substrate; a mirror face forming step of forming a mirror face for guiding light to the core by pressing a die provided with a blade having, in a cross-section, a 45° inclined plane into the photocurable resin sheet; a core forming step of forming a core having the mirror face positioned at an end thereof by selectively exposing to light, and developing, the photocurable resin sheet; and a cladding layer forming step of forming a second cladding layer so as to bury the core.

Abstract: Provided are a resin composition which offers both high transparency and a low linear expansion coefficient and can be used as a material for a dry film, and also a dry film obtained from this composition, an optical waveguide, and a photoelectric composite wiring board. The resin composition for an optical waveguide includes: (A) an epoxy resin constituted by a solid epoxy resin with one or less hydroxyl group in a molecule, and a liquid epoxy resin with one or less hydroxyl group in a molecule; (B) a curing agent with one or less hydroxyl group in a molecule; and (C) a nanosize silica sol, and contains no compound including two or more hydroxyl groups in a molecule as a resin component.

Abstract: An optical-electrical composite flexible circuit substrate having sufficiently high bending resistance is provided. An optical-electrical composite flexible circuit substrate includes: an optical circuit that includes a core portion and a cladding layer that covers the core portion; and an electrical circuit, with the optical circuit and the electrical circuit being disposed at a position that includes a neutral surface when the optical-electrical composite flexible circuit substrate is bent, or at a position near the neutral surface. Alternatively, the optical-electrical composite flexible circuit substrate may include an optical circuit that includes a core portion and a cladding layer that covers the core portion; and a substrate that includes an electrical circuit, with the substrate and the optical circuit being laminated so that the electrical circuit is disposed on a side closer to the optical circuit.

Abstract: An optical waveguide of excellent flex resistance which is to be formed on the surface of a flexible printed circuit is obtained by using an epoxy resin composition includes (A) a liquid epoxy compound, (B) a solid epoxy compound, and (C) a cationic curing initiator, wherein as the liquid epoxy compound (A), (A1) a liquid epoxy compound represented by general formula (I) below is included: (where R1 and R2 are each independently a hydrogen atom or a methyl group; R3 to R6 are each independently a hydrogen atom, a methyl group, a chlorine atom or a bromine atom; R7 is an alkyleneoxy group or alkylene group of 1 to 15 carbons; p is 0 or 1; q is 1 to 25; r and s are 0 when p is 0, and are 1 when p is 1; and n is a positive integer which averages from 1 to 5).

Abstract: An optical waveguide of excellent flex resistance which is to be formed on the surface of a flexible printed circuit is obtained by using an epoxy resin composition includes (A) a liquid epoxy compound, (B) a solid epoxy compound, and (C) a cationic curing initiator, wherein as the liquid epoxy compound (A), (A1) a liquid epoxy compound represented by general formula (I) below is included: (where R1 and R2 are each independently a hydrogen atom or a methyl group; R3 to R6 are each independently a hydrogen atom, a methyl group, a chlorine atom or a bromine atom; R7 is an alkyleneoxy group or alkylene group of 1 to 15 carbons; p is 0 or 1; q is 1 to 25; r and s are 0 when p is 0, and are 1 when p is 1; and n is a positive integer which averages from 1 to 5).

Abstract: In order to provide a method of manufacturing an optical waveguide, which enables the formation of a smooth mirror face, the following method of manufacturing an optical waveguide having a mirror face is used. The method includes: a photocurable resin sheet laminating step of laminating an uncured photocurable resin sheet for forming a core on a surface of a first cladding layer that has been formed on a substrate; a mirror face forming step of forming a mirror face for guiding light to the core by pressing a die provided with a blade having, in a cross-section, a 45° inclined plane into the photocurable resin sheet; a core forming step of forming a core having the mirror face positioned at an end thereof by selectively exposing to light, and developing, the photocurable resin sheet; and a cladding layer forming step of forming a second cladding layer so as to bury the core.

Abstract: In order to provide a method of efficiently manufacturing an optical waveguide core having an endface inclined at a predetermined angle, the following method of manufacturing an optical waveguide core is employed.