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1. (WO2018135500) DIFFRACTION LENS AND VEHICULAR LAMP USING SAME

Pub. No.:    WO/2018/135500    International Application No.:    PCT/JP2018/001059
Publication Date: Fri Jul 27 01:59:59 CEST 2018 International Filing Date: Wed Jan 17 00:59:59 CET 2018
IPC: G02B 5/18
F21S 41/00
F21S 43/00
F21S 45/00
F21W 103/00
F21W 104/00
F21W 105/00
Applicants: MAXELL JOEI TECH CO., LTD.
マクセル情映テック株式会社
Inventors: SHIMANO Takeshi
島野 健
Title: DIFFRACTION LENS AND VEHICULAR LAMP USING SAME
Abstract:
The purpose of the present invention is to provide a diffraction lens that is thin with excellent forming properties and can excellently form an image of a cutoff line for low beams in a vehicular lamp using a white light source. Provided is a diffraction lens having a protruding shape on both the light ray incident side and exit side, wherein the lens has an exit diffraction surface with an absolute value for the order of diffraction of 5 or greater disposed on the exit side, and has a shape such that the absolute value of the curvature at the surface apex of the envelope surface for the exit diffraction surface is smaller than the absolute value of the curvature at the surface apex on the incident surface, or the absolute value of the sag amount in the direction of the optical axis at the outer peripheral part of the envelope surface for the exit diffraction surface is smaller than the maximum absolute value for the sag amount in the direction of the optical axis at the outer peripheral part of the incident surface.