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:
Feb. 13, 2001
Filed:
Oct. 04, 1999
Syunsuke Kimura, Nishinomiya, JP;
Masayuki Takahashi, Ibaraki, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention provides a projection lens for projecting light from a light source onto a screen to form a magnified image, including two joined lenses, each of which includes a negative lens and a positive lens. The difference in the refractive index and the Abbe number between the negative lens and the positive lens in each of the joined lenses and the partial dispersion ratio of the negative lens and the positive lens of the second joined lens are specified. Thus, a large angle of view and a long back focal length can be achieved while satisfying distortion aberrations, telecentric properties and magnification chromatic aberrations.