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:
Nov. 08, 2011
Filed:
Dec. 22, 2008
Masayuki Imaoka, Izumiotsu, JP;
Keiko Yamada, Sakai, JP;
Masayuki Imaoka, Izumiotsu, JP;
Keiko Yamada, Sakai, JP;
Konica Minolta Opto, Inc., Hachioji-shi, JP;
Abstract
An oblique projection optical system enlarges an image formed on a display device surface, and obliquely projects the enlarged image on a screen surface. The oblique projection optical system has, in the order from a reduction side: a refraction optical portion having a positive optical power, a concave reflection surface having a positive optical power, and a convex reflection surface having a negative optical power. The refraction optical portion includes a rotationally symmetric coaxial refraction group. An intermediate image of the image formed on the display device surface is formed between the refraction optical portion and the concave reflection surface. An aperture stop image is formed between the concave reflection surface and the convex reflection surface. The concave reflection surface and the convex reflection surface fulfill prescribed conditional formulae.