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:
Sep. 08, 1987
Filed:
May. 13, 1985
Gerald R Porter, Burnsville, MN (US);
Thomas I Bradshaw, Afton, MN (US);
Eric N Hockert, Cottage Grove, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A directional image is created in transparent sheeting comprising a monolayer of microlenses by forming deformations in at least some of the microlenses by irradiation with a laser beam which has a short pulse duration. The directional images may be formed in transparent sheeting which has been applied to a document as an overlay. When viewed under diffuse lighting conditions, the deformations appear as a dark image. The deformations may be formed so that when viewed under retroreflective conditions within a conical field the image is darker than the surrounding background, and when viewed under retroreflective conditions outside the conical field the image is brighter than the surrounding background.