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:
Jul. 23, 1991
Filed:
Apr. 23, 1990
Jean-Claude Hennequin, Lizy-sur-Ourcq, FR;
Christian Massart, Clichy-Sous-Bois, FR;
Essilor International, Cie Generale d'Optique, Creteil, FR;
Abstract
An interpupillary distance measuring device comprises a box with a front panel whose position corresponds to an eyeglass frame. The device has a main axis perpendicular to the front panel and equidistant from the eyes of the subject. A horizon plane perpendicular to the plane of the face passes through the main axis and the eyes of the subject. In the box are a master lens and a point light source at the focus of the lens and on the main optical axis. The point source creates at the center of the eyes of the subject corneal reflections, virtual images of which are formed by the lens. These virtual images form real objects for an objective lens which forms a pair of real images on a measurement scale formed by one or more linear arrays of photosensitive charge transfer devices. The device scans sequentially to identify the elements of the arrays at which the images are formed by means of the rank of those elements.