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:
Jun. 05, 2007
Filed:
Jul. 05, 2005
Kimiaki Nakazawa, Kitakatsushika-gun, JP;
Fumio Watanabe, Kumagaya, JP;
Kimiaki Nakazawa, Kitakatsushika-gun, JP;
Fumio Watanabe, Kumagaya, JP;
Fujinon Corporation, Saitama, JP;
Abstract
A zoom lens for a projection display device includes, in order from the enlarging side, a first lens group having negative refractive power and that is stationary during zooming, second and third lens groups having positive refractive power, a fourth lens group that has refractive power that is much weaker in absolute value than the refractive powers of the other lens groups, and a fifth lens group having positive refractive power and that is stationary during zooming. The second, third, and fourth lens groups move with coordinated movements continuously toward the enlarging side during zooming from the wide-angle end to the telephoto end of the zoom range. The zoom lens satisfies certain conditions related to focal lengths of the zoom lens and lens groups and distances along the optical axis. A projection display device uses the zoom lens.