Patent ID: 8135246

Claim:
A three-dimensional sensor optical waveguide comprising: a plurality of frame-shaped optical waveguide members stacked coaxially in a thickness direction; and a measurement space defined by inner spaces of the stacked frame-shaped optical waveguide members; the optical waveguide members each including a light emitting core, a light receiving core and an over-cladding layer covering the cores; the light emitting core having a light output end positioned in one of opposed inner edge portions of each of the frame-shaped optical waveguide members, and a light input end positioned on an outer edge of each of the frame-shaped optical waveguide members; the light receiving core having a light input end positioned in the other inner edge portion of each of the frame-shaped optical waveguide members, and a light output end positioned on another outer edge of each of the frame-shaped optical waveguide members, wherein the light emitting core of each of the optical waveguide members includes a first lens portion provided at the light output end thereof and having a lens surface curved convexly outward into an arcuate plan shape, wherein the over-cladding layer of each of the optical waveguide members includes a second lens portion provided on an edge portion thereof which covers the lens surface of the first lens portion and has a lens surface curved convexly outward into an arcuate shape as seen in side section.