Browse Prior Art Database

New Polyimide for Ultra-Violet Type Two-Domain Twisted Nematic Panels

IP.com Disclosure Number: IPCOM000118571D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Lien, SA: AUTHOR

Abstract

The test data shows that Ultra-Violet type Two-Domain Twisted Nematic (UV-TDTN) panels using commercially available Polyimide (PI) have some problems. This can be seen from the fact that if PI does not receive enough UV dosage, the pretilt angle difference between the UV exposed area and non-exposed area is too small. However, if one wants to have a required pretilt angle difference, the panel may have problems of image sticking problem and alignment defect. The reason for this is that UV irradiation cleave both the side-chain and main chain of the PI. In the simple LC surface alignment picture, main chain is responsible for the alignment quality and the side-chain is responsible for the pretilt. Certain cleavages of side-chains are required to have a required pretilt angle difference.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

New Polyimide for Ultra-Violet Type Two-Domain Twisted Nematic Panels

      The test data shows that Ultra-Violet type Two-Domain Twisted
Nematic (UV-TDTN) panels using commercially available Polyimide (PI)
have some problems.  This can be seen from the fact that if PI does
not receive enough UV dosage, the pretilt angle difference between
the UV exposed area and non-exposed area is too small.  However, if
one wants to have a required pretilt angle difference, the panel may
have problems of image sticking problem and alignment defect.  The
reason for this is that UV irradiation cleave both the side-chain and
main chain of the PI.  In the simple LC surface alignment picture,
main chain is responsible for the alignment quality and the
side-chain is responsible for the pretilt.  Certain cleavages of
side-chains are required to have a required pretilt angle difference.
However, too much  cleavage on the main chain may cause the alignment
defect, as well as image sticking.

      A new PI is proposed which has a special linkage between main
chain and each side chain.  This linkage has the following
properties:
  1.  It can be cleaved using UV irradiation, especially
       deep-UV, with a low dose, such as lower then 800 mj/cm/cm.
  2.  It is not photosensitive to the visible, near-UV and IR
       light.  In other words, it is stable under the visible,
       near-UV and IR irradiation.
  3.  If it has not been exposed to UV, it is thermal stable.  It
       is stable at least up to 250 degree C.
  4.  If it has not been exposed to UV, it is stable for the PI
       going through the after rubbing...