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. 02, 1976
Filed:
Oct. 29, 1974
Narinder S Kapany, Woodside, CA (US);
Fred C Unterleitner, Palo Alto, CA (US);
Kaptron, Inc., Palo Alto, CA (US);
Abstract
Light from a bulb is projected through the microfiche transparency by a condensor and a projection lens system and the projected image therefrom is passed through a prism to viewing screen means. The prism has a flat or curved, transparent entrant surface for receiving the projected image, a flat, transparent exit surface facing the viewing screen means, a first, metal coated reflecting surface opposite to the entrant surface and forming a predetermined acute angle with the exit surface such that a major portion of the light beam passing through the entrant surface is reflected by the first reflecting surface to the exit surface at an incident angle greater than the critical angle for total internal reflection by the exit surface and a second, metal coated reflecting surface angularly facing the exit surface for returning the light beam reflected internally by the exit surface back to the exit surface at an incident angle which is less than the critical angle such that the returned light beam passes through the exit surface to impinge on the viewing screen means.