Did you ever heard abt electronic ink?

Lets learn smthing about it

Electronic ink is a liquid
substance, in development
... at MIT's Media Lab in
partnership with a
company called E Ink, that
responds to electrical impulses to enable
changeable text and image
displays on a flexible
surface. Electronic ink will
be used for applications
such as e-books, electronic newspapers, portable signs, and foldable, rollable
displays.

Electronic ink
consists of millions of tiny
capsules filled with dark
dyes and containing
negatively charged white chips, floating in a
substance like vegetable
oil. With a printer-like
device, the electronic ink-
coated material - which,
according to researchers, could be just about any flat
surface - is subjected to
electrical impulses that act
upon the white chips to
make them display as light
or dark-colored. A positive charge applied to an area
on the top of the display
medium causes the white
chips to float to the top
surface, and a charge
applied to an area on the bottom of the medium
causes them to drop to the
bottom. The pattern of
charges applied in concert
enables the display of
images and text.

Information to be
displayed is downloaded through a connection to a
computer or a cell phone, or created with mechanical
tools such as an electronic
"pencil".