Stock material or miscellaneous articles – Liquid crystal optical display having layer of specified...
Reexamination Certificate
2002-06-25
2004-11-23
Wu, Shean C. (Department: 1756)
Stock material or miscellaneous articles
Liquid crystal optical display having layer of specified...
C252S299640, C252S299650, C252S299670, C252S299620
Reexamination Certificate
active
06821581
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel optically active compound useful as a chiral dopant, a liquid crystal composition containing the compound and a liquid crystal display device to which the liquid crystal composition is applied. More specifically, it relates to a chiral dopant having a helical twisting power (HTP) of at least 9 and having the property that a helical pitch induced by the chiral dopant decreases with an increase in temperature, and use thereof.
2. Prior Art
Various modes are known as display modes of liquid crystal display devices, and in most of such display modes, it is required to control the helical pitch of a liquid crystal. The mode that requires control of the helical pitch of a liquid crystal includes the following modes.
The modes that have been put to practical use and widely employed are a twisted nematic mode (TN mode) and a super twisted nematic mode (STN mode) using a nematic liquid crystal.
In the TN mode, liquid crystal molecules are aligned so as to twist at 90 degrees between an upper substrate and a lower substrate, and a ¼ pitch of a helix is formed in a cell.
In the STN mode, liquid crystal molecules are aligned so as to twist at approximately 220 degrees between an upper substrate and a lower substrate, and an approximately ⅗ pitch of a helix is formed in a cell.
The TN mode is employed in a simple matrix driving liquid crystal display device and an active matrix driving liquid crystal display device, and the STN mode is employed in a simple matrix driving liquid crystal display device.
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English translation by computer for JP 5-4944, http://www4.ipdl.jpo.go.jp/Tokujitu/PAJdetail.ipdl?N000=60&N0120=01&N2001=2&N3001=H05-004944.*
English translatipon by computer for JP 05-25085, http://www6.ipdl.jpo.go.jp/Tokujitu/PAJdetail.ipdl?N0000=80&N0120=01&N2001=2&N3001=H05-025085.*
Nakauchi, J., et al. “Ferroelectric liquid crystal mixtures doped with compounds having chiral groups at both ends of the core.” Japanese Journal of Applied Physics, vol. 28, No 2. pp. L272-274, Feb. 1, 1989.
Johno Masahiro
Norisue Yasumasa
Ogi Yasue
Mitsubishi Gas Chemical Co. Inc.
Sherman & Shalloway
Wu Shean C.
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