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:
Mar. 11, 2008
Filed:
May. 17, 2004
Arno Schubert, Chevaigne, FR;
Pascal Benoit, Liffre, FR;
Arno Schubert, Chevaigne, FR;
Pascal Benoit, Liffre, FR;
Thomson Licensing, Boulogne Billancourt, FR;
Abstract
The invention relates to a Fresnel lens. Each refractive structure of the lens is bounded by two surfaces, the second surface making a second angle with the normal to the plane of incidence. At least two zones of refractive structures are provided in which the second angle is equal to the entrance angle of a beam. Each first surface refracts the light along a direction parallel or not parallel to the axis of the lens depending on the zone. The invention also relates to a system comprising a folding mirror and a Fresnel lens, in which system the second angle is equal to the entrance angle of a parasitic ray obtained by reflection on the Fresnel lens and then on the mirror. The invention also relates to a corresponding back projection screen and a corresponding back projection unit.