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:
Feb. 24, 1981
Filed:
Jun. 13, 1979
Terry J Scheffer, Forch, CH;
Hans R Zeller, Birr, CH;
BBC Brown, Boveri & Company, Limited, Baden, CH;
Abstract
A liquid crystal display is described for displaying dark signs on a light background in accordance with the guest-host principle without polarizers. The display includes parallel plates the insides of which are provided with an orientation layer which produces a homoeotropic orientation in an adjacent liquid crystal mixture. The liquid crystal mixture is formed primarily of a nematic liquid crystal having a high negative dielectric anisotropy and, secondarily, of an optically active substance. The proportion of the optically active substance is smaller than the quantity which would cause a spontaneous formation of a twisted structure in the liquid crystal mixture in the field-free state. The liquid crystal mixture is thus homoeotropically oriented and transparent throughout in the field-free regions, and is planar-cholesteric and absorbing in the activated regions.