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:
Aug. 08, 1995
Filed:
Nov. 05, 1993
Jonathan G Torrey, Portland, OR (US);
Cosmo Salibello, Portland, OR (US);
Prio Corporation, Lake Oswego, OR (US);
Abstract
A test card for use in eye examinations emulates the light return profile of a video display screen such as those commonly used in connection with computers. The test card is used for prescribing corrective lenses for a computer user. The test card is formed on an opaque planar medium and has a plurality of characters formed thereon for reading by the patient, each character formed by a plurality of pixel elements. The pixel elements may be formed by designing a pattern of dots on a computer system using graphic software for representing the resulting pattern in a machine-readable graphics file. The graphics file is used to control a compatible imagesetter machine for forming the desired pattern on photographic film. According to an alternative method, a film master is prepared in which each pixel is a solid black dot. The test card is prepared by printing the image onto photographic paper through a diffusion element so as to create an approximately Gaussian light return profile across each pixel.