OPTICAL APPARATUS FOR CONTROLLING DIVERGENCE ANGLE OF RING-LIKE RAY

摘要

An optical apparatus capable of emitting a ring-like pencil of ray having a uniform light intensity distribution. More particularly, this invention relates to an optical apparatus for controlling a divergence angle of a ring-like ray which can simultaneously irradiate slit beams each having a uniform intensity distribution and a narrow width at an arbitrary divergence angle with respect to the optical axis in a 360 DEG direction. This optical apparatus includes parallel beam generation means (2) into which light L1 outgoing from a light source (1) is introduced and which converts incident light L2 to parallel pencil of ray L3 and outputting it, ring-like beam generation means (3) to which the parallel pencil of ray L3 outgoing from the parallel beam generation means (2) is introduced and which converts this introduced light L4 to a ring-like pencil of ray L5 whose projection shape to an imaginary plane (not shown) vertical to the optical axis A - A describes a ring-like shape, and outputs this pencil of ray L5, and divergence angle changing means (4) for changing halfway the divergence angle theta 3 (angle between the optical axis A - A and the propagation direction of the ring-like pencil of ray L5) of the ring-like pencil of ray (5) outgoing from the ring-like beam generation means (3). The optical axes of the light source (1), parallel beam generation means (2), ring-like beam generation means (3) and divergence angle changing means (4) are adjusted so that their coupling efficiency becomes high as much as possible. This optical apparatus can be applied to a light emission device of an apparatus for measuring the radius of curvature of a curve surface of an object, etc.