ILLUMINATION DEVICE

摘要

An illuminating lens according to the present invention is provided with: an incident surface that is a surface configured so as to cover a light-emitting element located on a bottom part; an exit surface that is axisymmetric, positioned outside of the incident surface, and radiates light of the light-emitting element entering from the incident surface. The axis of the exit surface is the z-axis, the position of the bottom part of the illuminating lens is z=0, and the x and y axes are set in a plane perpendicular to the z-axis including z=0. The incident surface is symmetrical with respect to the yz-plane and xz-plane, and the cross-sectional area of a cross section parallel to the xy-plane of the incident surface decreases monotronically as the z-coordinate increases. The maximum value of the z-coordinate of the incident surface is d, and a point (x, y) on the cross section of the incident surface at the position where z=(1/3)d is expressed by the formula below, with a point existing on the cross section satisfying f(?)=0.95. Note that a<0.5r and b<0.5r, where a radii r of the cross section of the exit surface is z=0, a and b are positive constants, ?=tan-1(y/x), and f(0)=f(p/2)=1.0.