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:
Mar. 15, 1983
Filed:
Mar. 18, 1980
Isao Matsumura, Yokosuka, JP;
Yasuyuki Ishikawa, Kawaguchi, JP;
Shigeo Maruyama, Machida, JP;
Reiji Hirano, Yokohama, JP;
Yoshimi Kohayakawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In an apparatus having a ray generator for directing measuring rays through a first optical path, a light-receiving portion for receiving the measuring rays reflected by the eye fundus through a second optical path, and a uniting device for uniting the first and second optical paths to form a third optical path, and also having movable lens groups in each of the first and second optical paths or a movable lens group in the third optical path, and wherein the movable lens groups or group is moved along the optical path to measure the refractive power of the eye from signals corresponding to the positions of the movable lens groups or group and the signal of the light-receiving portion, the movable lens groups or group is made into an afocal system to prevent the dimensions of the pupil from being varied and a collimator for collimating the principal rays is fixedly disposed on that side of the movable lens groups or group which is adjacent to the eye to be examined.