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. 19, 1994
Filed:
May. 08, 1992
Carl-Zeiss-Stiftung, Heidenheim/Brenz, DE;
Abstract
A vision testing system includes polarization spectacles having different polarization axes with or without .lambda./4 filters for the two polarization lenses forward of the eye of the patient to be tested. This system also includes a vision testing apparatus for generating light having a specific polarization direction. The vision testing apparatus includes essentially two polarization filters and two LCD-displays which are mounted alternately one behind the other. This arrangement can so influence the light coming from the light source that test figures or portions of the test figures can be seen by one eye or by both eyes. If a test figure is to be changed, then a corresponding command is issued via a key pad to a switching unit which drives two drive circuits of the two LCD-displays in a desired manner. By making appropriate modifications of the vision testing apparatus, a patient can be tested as to color-vision acuity.