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:
Jan. 05, 1993
Filed:
Dec. 19, 1990
Joseph F Stephany, Williamson, NY (US);
Joseph J Wysocki, Webster, NY (US);
Sui K Hark, Shatin, HK;
Virgil J Hull, Perinton, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
Liquid crystal devices are provided with a DC current blocking layer which improves the lifetime of the liquid crystal device and also permits the use of two-level drivers, thus reducing the complexity of the driving scheme necessary to address the liquid crystal devices. Preferably, the blocking layer is the alignment layer which is made from poly-para-xylylene having a thickness sufficient to act as a DC blocking layer. Additionally, specific driving schemes for driving liquid crystal devices are provided. When the liquid crystal device includes a material which relaxes when no voltage is applied thereto (e.g., a nematic material), the information signal is entirely removed from alternating time frames during which the liquid crystal device is addressed. When the liquid crystal device includes a ferroelectric material, an arbitrarily large voltage potential is applied to the electrodes located on one side of the ferroelectric material for a first portion of a dwell time so that the pixels of the liquid crystal device are easily cleared of any previous information.