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Pretilt Angle Condition for Multi-Domain Liquid Crystal Display

IP.com Disclosure Number: IPCOM000117327D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Momoi, Y: AUTHOR [+5]

Abstract

Disclosed is the pretilt angle condition to get stable multi-domain alignment when we use ordinary Twisted Namatic (TN) liquid crystal materials with spray alignment as shown in Fig. 1. The pretilt angle of a inner surface should be not more than one degree and the difference of pretilt angles between two surfaces should be more than two degrees.

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Pretilt Angle Condition for Multi-Domain Liquid Crystal Display

      Disclosed is the pretilt angle condition to get stable
multi-domain alignment when we use ordinary Twisted Namatic (TN)
liquid crystal materials with spray alignment as shown in Fig. 1.
The pretilt angle of a inner surface should be not more than one
degree and the difference of pretilt angles between two surfaces
should be more than two degrees.

      As shown in Fig. 1, when we use a spray alignment of liquid
crystal to get controlled multi-domain state, it should be required
that pretilt angle of one surface is larger than that of the opposite
surface.  Also, lower pretilt angle should be not more than one
degree, because when two strong alignment forces face each other,
whole alignment direction of liquid crystal may be going unstable as
shown in Fig. 2.

      Therefore, to get stable multi-domain LCD, we must control the
pretilt angle of lower-angle side not more than one degree.  Also,
the difference of pretilt angle should be more than two degrees (*).

Reference
  (*) Y. Koike et. al, A Full-Color TFT-LCD with a Domain-Divided
       Twisted-Nematic Structure, SID 92 DIGEST (1992) 798