US Patent Issued to 3M Innovative Properties on June 3 for "Film stacks for thin circular polarizers" (Minnesota Inventors)

ALEXANDRIA, Va., June 4 -- United States Patent no. 12,321,000, issued on June 3, was assigned to 3M Innovative Properties Co. (St. Paul, Minn.).

"Film stacks for thin circular polarizers" was invented by Alex P. Pongratz (Minneapolis), David T. Yust (Woodbury, Minn.) and Michael A. Johnson (Stillwater, Minn.).

According to the abstract* released by the U.S. Patent & Trademark Office: "Film stacks comprise a quarter-wave retarder and a transparent aliphatic cross-linked polyurethane layer disposed on a major surface of the quarter-wave retarder. The transparent aliphatic cross-linked polyurethane layer has a glass transition temperature in a range from 11 to 27deg C. and a Tan Delta peak value in a range from 0.5 to 2.5."

The patent was ...