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:
Jun. 30, 2015
Filed:
Jun. 13, 2011
Michael F. Weber, Shoreview, MN (US);
Yufeng Liu, Woodbury, MN (US);
Stephen A. Johnson, Woodbury, MN (US);
David T. Yust, Woodbury, MN (US);
Michael F. Weber, Shoreview, MN (US);
Yufeng Liu, Woodbury, MN (US);
Stephen A. Johnson, Woodbury, MN (US);
David T. Yust, Woodbury, MN (US);
3M Innovative Properties Company, St. Paul, MN (US);
Abstract
An optical stack () having a plurality of alternating polymeric layers () is described. The alternating layers may be alternating birefringent (syndiotactic polystyrene, sPS) and isotropic (CoPENa) layers, or alternating positively and negatively birefringent layers. Birefringent layers are made using polymers which form optically symmetrical crystallites upon stretching of the polymer. The optical stack has a large refractive index difference in the x-direction (the stretching direction) and small refractive index differences in the y- and z-directions (the non-stretching directions). The optical stack can be made using standard film tentering methods and may be a multilayer reflective polarizer.