Patent ID: 7239599

Claim:
A light irradiation head comprising: a propagation body which has a tapered two dimensional shape axially symmetrical to a predetermined symmetrical axis, and which consists of a first kind material that propagates electromagnetic fields of light; and a covering body which covers the propagation body so as to surround the symmetrical axis, and which consists of a second kind material different from the first kind material, the light irradiation head irradiating light propagating in the propagating body, from the tip of the propagating body, wherein the propagation body comprises: a bottom edge of projecting shape or recessed shape which is present on the symmetrical axis and which is axially symmetrical to the symmetrical axis; a tip edge which is present on the symmetrical axis and which is narrow relative to the bottom edge; and a pair of reflective edges which are present on both sides of the symmetrical axis, and of which interval is gradually reduced in the direction from the bottom edge side to the tip edge side.