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:
May. 22, 1990
Filed:
Jun. 10, 1985
Seiko Epson Corporation, Tokyo, JP;
Abstract
A high-speed responsive liquid crystal optical device with improved light transmissivity is provided. The device includes a liquid crystal panel including an optically active liquid crystal material having dielectric anisotropy which becomes zero at a crossing frequency ('fc') of 100 KHz or below. The dielectric anisotropy of the liquid crystal is positive at frequencies lower than fc ('fl') and negative at frequencies higher than fc ('fh'). Crossed polarizers are disposed on each side of the liquid crystal panel. A liquid crystal driving circuit selectively applies a signal of a frequency fh to open the device and a signal of a frequency fl to close the device. The optical device is particularly well suited for use as a light valve in a printer device. Response time within 1 m sec. permits a printing speed of 10 prints of A4 size to be produced per minute with a resolving power of about 10 dots per 1 m/m. This amounts to a printing speed of approximately 500 lines in one second with each line being written into m sec. or less. The optically active nematic liquid crystal is a composition comprising an optically inactive nematic liquid crystal and an optically active liquid crystal material added thereto.