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. 28, 1995
Filed:
Nov. 24, 1993
Jack B Stubbs, Waynesville, OH (US);
John A Cartmill, Cleveland Heights, OH (US);
Ethicon, Inc., Cincinnati, OH (US);
Abstract
A novel chart permits rapid and inexpensive evaluation of an optical instrument for manufacturing purposes and/or by an operator of the instrument. For example, a user of an optical instrument may directly test the performance of an instrument without the assistance of trained personnel or a well-equipped laboratory facility. The chart comprises a plurality of levels defined by blocks having converging lines extending therein. The plurality of levels define a corresponding plurality of contrast levels between their blocks and the converging lines therein. The chart is used by viewing a plurality of levels within the chart and determining corresponding line frequency values at which the viewer is unable to discern multiple lines. These line frequency values are then compared to calibration line frequency values for the instrument being evaluated. The chart of the present invention is easily transported and used, and may be supplied along with an optical instrument to define operating characteristics of the instrument.