OPTICAL MEASUREMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical measurement device capable of suppressing breakage due to heat and detecting light emitted from a direction different from a direction along a center shaft of a lens.SOLUTION: An optical measurement device 5 detects combustion process in a combustion chamber of an internal combustion and comprises: a housing 10 whose tip end is disposed in the combustion chamber; a convex lens 61 having a convex spherical part, disposed in the housing and condensing light in the combustion chamber; and a light transmission medium 70 coupled to the convex lens at a position offset from a center shaft 110 of the spherical part of the convex lens, and guiding the condensed light condensed by the convex lens to an optical detection part 80 of the optical measurement device.