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. 04, 1992
Filed:
Jan. 22, 1991
Applicant:
Inventors:
John F Dreyer, Jr, St. Paul, MN (US);
Dennis J Roden, St. Paul, MN (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
353 85 ; 353 66 ; 353 94 ; 353D / ;
Abstract
A reflective overhead projector is provided with two lamps for the purpose of allowing change from one to the other of the lamps in the event of expiration of the lamp in use. The lamps are arranged to face the center of a circle at which is positioned a rotatable planar mirror which may be turned to direct light from a desired one of the two lamps. An electrical switch senses the position of the mirror and directs electrical power to the appropriate lamp.