Abstract: A method for manufacturing an optical waveguide includes: step A of forming a first resin layer 23 by allowing a first liquid-state resin to flow to be extended in a manner so as to bury and enclose cores 22; step B of forming a second resin layer 25 by allowing a second liquid-state resin having a viscosity higher than that of the first liquid-state resin to flow to be extended on the first resin layer 23, after or while the first resin layer 23 is heated; and step C of forming an over-cladding layer 26 by curing the first resin layer 23 and the second resin layer 25.

Abstract: A method for manufacturing an optical waveguide which comprise the steps of: filling an ultraviolet curable liquid-state resin 17 to form an over-cladding layer 14 in a concave portion 16 of a die 15; bringing an under-cladding layer 12 and a core 13 into close contact with the ultraviolet curable liquid-state resin 17 filled in the concave portion 16 of the die 15; and irradiating ultraviolet rays 24 from a substrate 11 side after bringing the under-cladding layer 12 into close contact with the die 15 by the application of a pressure 23 onto the substrate 11 and the die 15 to cure the ultraviolet curable liquid-state resin 17 and then removing the die 15.

Abstract: A method for manufacturing an optical waveguide includes the steps of: A) forming a liquid-state resin mass by adding dropwise a liquid-state resin on an under-cladding layer; B) forming a liquid-state resin layer to cover cores by pressing a mold on the liquid-state resin mass and applying the liquid-state resin to be expanded on the under-cladding layer; and C) curing the liquid-state resin layer and then releasing the mold, wherein the liquid-state resin added dropwise has a viscosity of 500 to 2,000 mPa·s and the rate at which the liquid-state resin is applied to be expanded is 10 to 50 mm/s.

Abstract: A method for manufacturing an optical waveguide includes: step A of forming a first resin layer 23 by allowing a first liquid-state resin to flow to be extended in a manner so as to bury and enclose cores 22; step B of forming a second resin layer 25 by allowing a second liquid-state resin having a viscosity higher than that of the first liquid-state resin to flow to be extended on the first resin layer 23, after or while the first resin layer is heated; and step C of forming an over-cladding layer by curing the first resin layer 23 and the second resin layer 25.

Abstract: A resin layer 13 that flows to be extended on the surface of cores 12 and then a concave-shaped mold 16 having a vent hole 15 is pressed to discharge bubbles 14 contained in the resin layer 13 to the outside through the vent hole 15. In such a manner, the bubbles 14 remaining on the periphery of the cores 12 can be effectively reduced. As a result, a method for manufacturing an optical waveguide with high light transmission efficiency is obtained.

Abstract: The present invention provides a forming die having a mold releasing layer formed on a die surface of the forming die, the mold releasing layer containing a fluororesin and having a film thickness of 10 to 500 nm; a production process of a microlens including forming a resin by using the forming die; and a microlens produced by the production process. The forming die is capable of transferring a precise shape of a die surface of the forming die to optical parts as designed.

Abstract: The invention provides a process for producing an optical waveguide, which comprises the steps of: forming a substrate adhesion layer on a surface of a substrate from a layer-forming material containing a coupling agent; forming an undercladding layer on the substrate adhesion layer; and forming a core layer having a predetermined pattern on the undercladding layer through a wet process with a developing solution.

Abstract: A photosensitive polyimide resin precursor composition capable of providing a polyimide resin that is not substantially colored, is transparent and has heat resistance, an optical polyimide resin obtained from the composition, and an optical waveguide using the polyimide resin. The photosensitive polyimide resin precursor composition contains (a) 100 parts by weight of a polyamic acid obtained from a tetracarboxylic acid dianhydride and a diamine, (b) 0.01 parts by weight or more and less than 5 parts by weight of a 1,4-dihydropyridine derivative, (c) 5–50 parts by weight of a glycol (ether). The optical polyimide resin is obtained by irradiating the photosensitive resin precursor composition with UV light, followed by exposure, heating, development, and then heating. The optical waveguide comprises a core layer comprising the optical polyimide resin, and a cladding layer thereof.

Abstract: The invention provides a process for producing an optical waveguide, which comprises the steps of: continuously applying a polyimide resin precursor layer on a long-sheet substrate and then curing the layer to form a lower cladding layer; continuously applying a photosensitive polyimide resin precursor layer on the lower cladding layer; continuously exposing the applied photosensitive polyimide resin precursor layer to a light through a photomask having a predetermined pattern; continuously conducting post-exposure heating of the exposed polyimide resin precursor layer; continuously developing the polyimide resin precursor layer after the heating to thereby remove unexposed areas thereof and give a predetermined pattern; curing the developed polyimide resin precursor layer to thereby form a core layer having the predetermined pattern on the lower cladding layer; and continuously applying a polyimide resin precursor layer over the lower cladding layer so as to cover the core layer and then curing the precursor

Abstract: The invention provides a process for producing an optical waveguide, which comprises the steps of: forming a substrate adhesion layer on a surface of a substrate from a layer-forming material containing a coupling agent; forming an undercladding layer on the substrate adhesion layer; and forming a core layer having a predetermined pattern on the undercladding layer through a wet process with a developing solution.

Abstract: A photosensitive polyimide resin precursor composition capable of providing a polyimide resin that is not substantially colored, is transparent and has heat resistance, an optical polyimide resin obtained from the composition, and an optical waveguide using the polyimide resin. The photosensitive polyimide resin precursor composition contains (a) 100 parts by weight of a polyamic acid obtained from a tetracarboxylic acid dianhydride and a diamine, (b) 0.01 parts by weight or more and less than 5 parts by weight of a 1,4-dihydropyridine derivative, (c) 5-50 parts by weight of a glycol (ether). The optical polyimide resin is obtained by irradiating the photosensitive resin precursor composition with UV light, followed by exposure, heating, development, and then heating. The optical waveguide comprises a core layer comprising the optical polyimide resin, and a cladding layer thereof.