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. 09, 2000
Filed:
Feb. 06, 1998
Hiroyuki Takahashi, Yokohama, JP;
Kenji Kameyama, Sagamihara, JP;
Yasuyuki Takiguchi, Sagamihara, JP;
Akihiko Kanemoto, Yokohama, JP;
Fuminao Matsumoto, Tokyo-to, JP;
Kazuya Miyagaki, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A liquid crystal display device includes a liquid crystal display cell having a layer of a twisted-nematic liquid crystal material with a positive dielectric anisotropy constant and constructed such that a plurality of voltage potentials applied to the liquid crystal cell may firstly induce a Freedricksz transition of the liquid crystal material and then select either one of first and second metastable states caused by relaxation of the liquid crystal material succeeding the Freedricksz transition. A first voltage potential is adjusted higher than a threshold voltage necessary to cause changes from an initial state to the metastable states, a second voltage potential to select one of the metastable states is adjusted in comparison with a voltage potential necessary to switch between the metastable states, and a third voltage potential is applied as a modulation voltage during or succeeding the application of the second voltage potential. By applying at least one of these voltage potentials, the modulation of the metastable states can be carried out, thereby causing arbitrary changes in transmittance of the liquid crystal cells and achieving a multilevel gray scale in the liquid crystal display device.