Ion Bombardment of Polyimide for the Alignment of Liquid Crystals

Ion Bombardment of Polyimide for the Alignment of Liquid Crystals

      The active matrix liquid crystal displays (AMLCDs) (see,
e.g., [1]) as drawn much attention because they can display more
information with better performance than conventional multiplexing
LCDs.  The liquid crystal alignment in an AMLCD is commonly achieved
by using a rubber polyimide film.  This alignment method gives the
LCD a good alignment quality and a long term stability.  However, the
mechanical rubbing may cause mechanical and/or electro-static damage
to the active matrix elements.  The rubbing method may also cause
particle contamination of the plate.  Therefore, it is not a good
method to align an active matrix.  In this article, a new alignment
method is described.  Use of this new method to align an active
matrix LCD will prevent the electro-static and mechanical damage to
the active matrix elements.

      An ion beam process is described herein, whereby a polyimide-
coated surface can be textured such that liquid crystals can be
aligned in the proper orientation for flat panel display
applications, expecially for the active matrix LCD application.  The
active matrix plate and its counter-plate are first coated with
polyimide.  They are then placed in the ion beam chamber with the
substrate surface making a proper angle (typical 5o to 30o) with
respect to the ion beam.  The proper energy of the bombarded ion beam
will texture the coated polyimide film which will then align the
liquid crystal.  The ion beam can be generated by, but is not limite...