The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 18, 2017
Filed:
Sep. 18, 2013
Teknologian Tutkimuskeskus Vtt, Vuorimiehentie, FI;
DISPELIX OY, Helsinki, FI;
Abstract
The invention relates to optical devices comprising a transparent substrate and a first transparent grating layer on the substrate, the grating layer comprising periodically alternating zones having different refractive indices. According to the invention, the device comprises a second transparent grating layer located on top of the first grating layer and also comprising periodically alternating zones having different refractive indices so that the zones of the first grating layer having higher refractive index are at least partly aligned with the zones of the second grating layer having lower refractive index and vice versa, the second grating layer reducing the amount of light diffracted to non-zero transmission orders. The invention allows for reducing the so-called rainbow effect for example in head-up displays (HUDs).