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:
Oct. 06, 1987
Filed:
Apr. 25, 1985
Thomas E Bernard, Whitehall, PA (US);
Emile M Roth, Pittsburgh, PA (US);
Edwin R Mohan, Braddock Hills, PA (US);
Gary W Sherwin, South Huntingdon Township, Westmoreland County, PA (US);
John M Zomp, N, Huntingdon, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
An evoked potential autorefractometry system includes a computer driving an alternating checkerboard mirror stimulus to project a stimulus pattern directly to a patient through a continuously variable focus lens controlled by the computer and which maintains a constant image size on the patient's retina. The evoked potentials produced by the patient are amplified, asychronously filtered both in an analog and digital fashion to allow peak to peak detection of the evoked potentials to determine amplitude. The digital filter includes a 255 point running sum. The peak to peak amplitudes are asychronously digitally filtered using a 16 point running sum to produce an amplitude measure of the evoked potentials. The lens is swept rapidly from one extreme of focus to the other extreme in relatively large steps to determine the area in which the peak amplitude occurs. The lens is then subsequently swept in smaller and smaller range sweeps using smaller and smaller steps around the peak amplitude until the peak in the amplitude is pinpointed within a desired diopter at which point the lens position is printed out on the printer as the patient's prescription.