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:
Jan. 25, 1983
Filed:
Jul. 15, 1980
Masao Nohda, Yokohama, JP;
Nippon Kogaku K.K., Tokyo, JP;
Abstract
An ophthalmological instrument capable of continuously changing the size of an observed image is disclosed. The instrument comprises an image forming optical system for forming a first observed image, a magnification changing optical system for forming a second observed image from said first image and continuously changing the size of said second image and a correction member for correcting the optical length. To continuously change the size of said second image for observation, the magnification changing optical system includes a positive lens group and a negative lens group which are movable relative to each other in the direction of the optical axis. In order to keep constant the positions of the anterior and posterior focal points of the magnification changing optical system, that is, a composite system of the two lens groups, the optical length correction member is movable in association with the movements of the positive and negative lens groups.