	US 12,105,254 B2
	Element for covering the projection aperture of a heads-up display device
Thomas Lopez, Paris (FR); David Barat, Clamart (FR); Laetitia Pradere, Bievres (FR); and Béatrice Dagens, Antony (FR)
Assigned to STELLANTIS AUTO SAS, Poissy (FR); CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and UNIVERSITE PARIS-SUD, Orsay (FR)
Appl. No. 17/638,305
Filed by PSA AUTOMOBILES SA, Poissy (FR); CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and UNIVERSITE PARIS-SUD, Orsay (FR)
PCT Filed Aug. 20, 2020, PCT No. PCT/FR2020/051487 § 371(c)(1), (2) Date Feb. 25, 2022, PCT Pub. No. WO2021/048480, PCT Pub. Date Mar. 18, 2021.
Claims priority of application No. 1909989 (FR), filed on Sep. 11, 2019.
Prior Publication US 2022/0326414 A1, Oct. 13, 2022
Int. Cl. G02B 1/18 (2015.01); G02B 1/116 (2015.01); G02B 27/01 (2006.01)

CPC G02B 1/18 (2015.01) [G02B 1/116 (2013.01); G02B 27/0101 (2013.01)]

9 Claims

1. A dust-proof covering element arranged to close a projection aperture in a dashboard of a vehicle and through which an information-carrying source light beam projected by a projecting module from a heads-up display device passes on its way to a partially reflective return element, said covering element comprising a transparent carrier and an optical coating placed on a face of said transparent carrier; wherein said optical coating comprises a metal layer having plasmonic properties, said metal layer being provided with an array of subwavelength nanoperforations, and configured to allow an extraordinary transmission of one or more restricted bands of wavelengths of the visible spectrum that are centered on one or more wavelengths of the light beam projected by said projecting module, wherein said optical coating comprises a layer of transparent magneto-optical material interposed between said transparent carrier and said metal layer and interacting with said metal layer to make said extraordinary transmission non-reciprocal so that said wavelength or wavelengths of the light beam projected by said projecting module are transmitted only in a first direction going from this projecting module toward said return element, and so that the other visible wavelengths of said restricted band or bands are transmitted only in an opposite second direction going from the return element toward the projecting module.