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:
Jul. 10, 2012
Filed:
Aug. 27, 2009
Applicants:
Patrick M. Campbell, Saint Paul, MN (US);
Erich C. Walter, Woodbury, MN (US);
Inventors:
Patrick M. Campbell, Saint Paul, MN (US);
Erich C. Walter, Woodbury, MN (US);
Assignee:
3M Innovative Properties Company, St. Paul, MN (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F 3/038 (2006.01);
U.S. Cl.
CPC ...
Abstract
A gray scale drive scheme for passive matrix displays, more specifically cholesteric liquid crystal displays. Prior to writing an image, the display can be given a black appearance by first driving the pixels to a homeotropic state, then driving the pixels to a focal conic state. The drive scheme then resets pixels by driving the selected pixels to a homeotropic state. Selecting and non-selecting row voltage signals are then used in combination with column voltage signals to write an image to the display.