LENS FOR SPOTLIGHT

• Main Author: ASAKAWA HISASHI
• Format: Patent
• Language: English
• Published: 15.08.1997
• Edition: 6
• Subjects: BLASTING; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; HEATING; LIGHTING; MECHANICAL ENGINEERING; NON-PORTABLE LIGHTING DEVICES; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLEEXTERIORS; WEAPONS

PROBLEM TO BE SOLVED: To prevent the circumferential part of an irradiation light from blurred and reduce the weight of a lens itself by setting the circumferential part of the lens surface to a similar shape to a convex lens and the central part being inward from the circumferential part to a similar shape to a Fresnel lens. SOLUTION: The first surface (a rear surface) 1a of a lens 1 is formed into a flat surface and the circumferential part 2 of the second surface (a front surface) 1b of the lens 1 is formed into a smooth curved surface (the similar shape to the second surface of a flat convex lens). The central part 3 is formed into a recessed curved face, steps 4 are formed into a Fresnel lens shape cut in a stepped state, and the Fresnel lens is so constituted that the center is formed from a spherical shape and the stepped step surface except for the center is formed from the 4-dimensional curved surface obtained by rotating an arch, which is formed by deviating the curvature center from the optical axis, about the optical axis. This constitution can reduce the weight of the lens itself, while securing superior light quality of the circumferential part of irradiation light obtained from the flat convex lens.