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Method to Suppress Reverse Twist State for Ultraviolet Two-Domain Liquid Crystal Display and Other Splay Type Two-Domain Liquid Crystal Displays

IP.com Disclosure Number: IPCOM000118679D
Original Publication Date: 1997-May-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Lien, S-CA: AUTHOR [+2]

Abstract

Fig. 1 shows a typical two-domain boundary for a horizontal Ultra-Violet (UV) boundary of a Ultra-Violet-Two-Domain Twisted Nematic (UV-TDTN) pixel. As shown in Fig. 1, Two boundary are not coincided. Thus, two different Liquid Crystal (LC) configurations exist within a pixel. Areas I and IV are configuration I, which has normal tilt (LCs in mid-plane tilt in the same direction as that of higher pretilt surface) and normal twist configuration (twist in the same sense as that of the chiral agent of LC).

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Method to Suppress Reverse Twist State for Ultraviolet Two-Domain
Liquid Crystal Display and Other Splay Type Two-Domain Liquid Crystal
Displays

      Fig. 1 shows a typical two-domain boundary for a horizontal
Ultra-Violet (UV) boundary of a Ultra-Violet-Two-Domain Twisted
Nematic (UV-TDTN) pixel.  As shown in Fig. 1, Two boundary are not
coincided.  Thus, two different Liquid Crystal (LC) configurations
exist within a pixel.  Areas I and IV are configuration I, which has
normal tilt (LCs in mid-plane tilt in the same direction as that of
higher pretilt surface) and normal twist configuration (twist in the
same sense as that of the chiral agent of LC).

      Areas II and III are configuration II, which has reverse tilt
(LCs in mid-plane tilt in the opposite direction to that of higher
pretilt surface) and normal twist configuration.  Configuration II is
easier to convert into reverse twist state (twist in the opposite
sense to that of the chiral agent of the LC).  The reverse twist
state is a defect for the two-domain structure since the viewing
angle behavior is  different from what was designed for.

      This invention discloses new UV boundaries which minimize
the area of the configuration II.  Thus, the reverse twist state is
suppressed.  The basic idea is to design an UV boundary so that the
two-domain boundary and UV boundary are coincided or almost
coincided.  The disclosed structures are shown in Fig. 2.

The advantage of these new UV boundar...