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. 17, 1987
Filed:
Aug. 03, 1984
Applicant:
Inventors:
Bruce D Orensteen, St. Paul, MN (US);
Thomas I Bradshaw, Afton, MN (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
350105 ;
Abstract
Retroreflective sheeting of the prior art comprises a monolayer of transparent glass microspheres partially embedded in a binder layer and a specularly reflective layer covering the back surfaces of the microspheres. In the prior art, a laser beam directed at an angle to the face of the sheeting forms an image in such sheeting which is directional in that it can be viewed only from that angle. In the invention, such a directional image is provided by tiny ellipsoidal cavities, each opening through a back surface of the microsphere.