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:
Oct. 14, 2003
Filed:
Feb. 21, 2001
Ken Wada, Tochigi-ken, JP;
Saburo Sugawara, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A projection lens of the following structure was invented for the purpose of providing a bright projection optical system with the F-number of approximately 2 or lower while maintaining good optical characteristics, in an image display apparatus. The projection lens is constructed of six lens units, a first lens unit L of a negative optical power, a second lens unit L of a positive optical power, a third lens unit L of a positive optical power, a fourth lens unit L of a negative optical power, a fifth lens unit L and a sixth lens unit L of a positive optical power, in the order named from the enlargement conjugate side, and four lens units (L to L ) out of the lens units move toward the enlargement conjugate side during zooming from the wideangle extreme to the telephoto extreme.