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:
May. 31, 2011
Filed:
Dec. 26, 2007
Masayuki Imaoka, Izumiotsu, JP;
Jun Ishihara, Kobe, JP;
Masayuki Imaoka, Izumiotsu, JP;
Jun Ishihara, Kobe, JP;
Konica Minolta Opto, Inc., Hachioji-shi, JP;
Abstract
A rear projector for performing image projection includes: a screen and a projection optical system. The screen has a rotationally symmetric Fresnel lens. The projection optical system has at least one reflection surface formed of a rotationally asymmetric free curved surface. The projection optical system is nonaxisymmetric and makes a central principle ray incident obliquely on the screen in the image projection. The Fresnel lens has aberration that cancels out pupil aberration of the projection optical system so that principal rays of beams exiting from the Fresnel lens become substantially parallel to each other.