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. 21, 1986
Filed:
Feb. 21, 1984
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The disclosed zoom lens includes, from front to rear, a first lens component of positive power for focusing the lens, a second lens component of negative power for varying magnification power, a third lens component of negative power for compensating for the image shift resulting from the change of magnification power, and a fourth lens component of positive power for forming an image. The second lens component includes, from front to rear, a negative meniscus-shaped lens having a strong refracting rear surface, and another negative mensicus-shaped lens having a strong refracting front surface and a cemented surface of forward convexity. A front group of the fourth component includes, from front to rear, a bi-convex lens having a rear surface of strong curvature, another bi-convex lens having a front surface of strong curvature, a lens of negative power having a front surface of strong curvature and a lens of positive power having a front surface of strong curvature. The second group of the fourth component includes, from front to rear, a bi-concave lens having a rear surface of strong curvature, a bi-convex lens having a rear surface of strong curvature, and another bi-convex lens having a front surface of strong curvature. This permits a compact lens with good correction throughout the zooming range.