This invention relates to an electrophoretic display or a liquid crystal display
and novel processes for its manufacture. The electrophoretic display (EPD) of the
present invention comprises microcups of well-defined shape, size and aspect ratio
and the microcups are filled with charged pigment particles dispersed in an optically
contrasting dielectric solvent. The liquid crystal display (LCD) of this invention
comprises well-defined microcups filled with at least a liquid crystal composition
having its ordinary refractive index matched to that of the isotropic cup material.
A novel roll-to-roll process and apparatus of the invention permits the display
manufacture to be carried out continuously by a synchronized photo-lithographic
process. The synchronized roll-to-roll process and apparatus permits a pre-patterned
photomask, formed as a continuous loop, to be rolled in a synchronized motion in
close parallel alignment to a web which has been pre-coated with a radiation sensitive
material, so as to maintain image alignment during exposure to a radiation source.
The radiation sensitive material may be a radiation curable material, in which
the exposed and cured portions form the microcup structure. In an additional process
step, the radiation sensitive material may be a positively working photoresist
which temporarily seals the microcups. Exposure of a selected subset of the microcups
via the photomask image permits selective re-opening, filling and sealing of the
microcup subset. Repetition with additional colors permits the continuous assembly
of a multicolor EPD or LCD display.
