Optical waveguide and manufacturing method thereof

Abstract

The optical waveguide includes: a lower clad layer, a core layer, an upper clad layer, a substrate, and a mirror, the lower clad layer, the core layer, and the upper clad layer being sequentially laminated to the substrate, the mirror being formed on the core layer, in which the substrate has an opening, the maximum diameter of the opening is larger than that of luminous flux reflected by the mirror, and the maximum diameter of the opening is 240 μm or less. The optical waveguide is capable of transmitting a light signal regardless of the type of the substrate, suppressing the spread of a light signal reflected from the mirror, and transmitting a light signal with a low optical transmission loss.

We claim: 
     
         1 . An optical waveguide comprising: a lower clad layer, a core layer, an upper clad layer, a substrate, and a mirror, the lower clad layer, the core layer, and the upper clad layer being sequentially laminated to the substrate, the mirror being formed on the core layer, wherein the substrate has an opening, the maximum diameter of the opening is larger than that of luminous flux reflected by the mirror, and the maximum diameter of the opening is 240 μm or less, and a pillar-shaped transparent member projecting from the opening beyond the back surface direction of the substrate, wherein a projecting part of the pillar-shaped transparent member has a pillar shape. 
     
     
         2 . The optical waveguide according to  claim 1 , further comprising a reinforcing plate connected with at least a part of the sidewall of the pillar-shaped transparent member. 
     
     
         3 . The optical waveguide according to  claim 2 , wherein the reinforcing plate is pattern-formed. 
     
     
         4 . The optical waveguide according to  claim 2 , wherein the reinforcing plate is a metal layer. 
     
     
         5 . The optical waveguide according to  claim 1 , further comprising a transparent resin layer A formed of a transparent resin a between the substrate and the lower clad layer, wherein the opening is filled with the transparent resin a. 
     
     
         6 . The optical waveguide according to  claim 1 , further comprising a transparent resin layer B formed of a transparent resin b on the surface opposite to the lower clad layer formed surface of the substrate, wherein the opening is filled with a resin composition forming the lower clad layer and the transparent resin b. 
     
     
         7 . The optical waveguide according to  claim 1 , further comprising a transparent resin layer A formed of a transparent resin a between the substrate and the lower clad layer, wherein at least a part of the opening on the substrate is filled with the transparent resin a, and the pillar-shaped transparent member formed of a transparent resin b is in contact with the transparent resin a in the opening. 
     
     
         8 . The optical waveguide according to  claim 1 , wherein at least a part of the opening on the substrate is filled with a resin component for forming a clad layer to form the lower clad layer, and the pillar-shaped transparent member formed of a transparent resin b is in contact with the resin component in the opening. 
     
     
         9 . The optical waveguide according to  claim 1 , wherein at least a part of the opening on the substrate is filled with a resin component for forming a core layer to form the core layer, and the pillar-shaped transparent member formed of a transparent resin b is in contact with the resin component in the opening. 
     
     
         10 . The optical waveguide according to  claim 1 , wherein the mirror is formed immediately above the opening. 
     
     
         11 . The optical waveguide according to  claim 5 , wherein the transparent resin a is a resin composition for forming a clad layer or a resin composition for forming a core layer. 
     
     
         12 . The optical waveguide according to  claim 6 , wherein the transparent resin b is a photosensitive resin composition. 
     
     
         13 . The optical waveguide according to  claim 12 , wherein the transparent resin b is a resin composition for forming a clad layer or a resin composition for forming a core layer. 
     
     
         14 . The optical waveguide according to  claim 12 , wherein the transparent resin b is a photosensitive resin composition for protecting electrical wiring. 
     
     
         15 . The optical waveguide according to  claim 6 , wherein the substrate is capable of shielding active light for light-curing the transparent resin b.