Electronic
paper utilizes a new display technology called "gyricon,"
invented by Xerox. A gyricon sheet is a thin layer of transparent
plastic in which millions of small beads, somewhat like toner
particles, are randomly dispersed. The beads, each contained
in an oil-filled cavity, are free to rotate within those cavities.
The beads are "bichromal," with hemispheres of contrasting
color (e.g. black and white), and charged so they exhibit an
electrical dipole.
Under the
influence of a voltage applied to the surface of the sheet, the
beads rotate to present one colored side or the other to the
viewer. A pattern of voltages can be applied to the surface in
a bit-wise fashion to create images such as text and pictures.
The image will persist until new voltage patterns are applied
to create new images.
There are
many ways an image can be created in electronic paper. For example,
sheets can be fed into printer-like devices that will erase old
images and create new images. Used in these devices, the electronic
paper behaves like an infinitely reusable paper surrogate.
Although
projected to cost somewhat more than a normal piece of paper,
a sheet of electronic paper could be reused thousands of times.
Printer-like devices can be made so compact and inexpensive that
you can imagine carrying one in a purse or briefcase at all times.
One such envisioned device, called a wand, can be pulled across
a sheet of electronic paper by hand to create an image. With
a built-in input scanner, this wand becomes a hand-operated multi-function
device - printer, copier, fax, and scanner all in one.
For applications
requiring more rapid and direct electronic update, the gyricon
material might be packaged with a simple electrode structure
on the surface and used more like a traditional display. An electronic
paper display could be very thin and flexible. A collection of
these electronic paper displays could be bound into an electronic
book. With the appropriate electronics stored in the spine of
the book, pages could be updated at will to display different
content.
For portable
applications, an active matrix array may be used to rapidly update
a partial or full-page display, much like is used in today's
portable devices. The lack of a backlight and eliminated requirement
to refresh the display (since it is bistable), along with improved
brightness compared to today's reflective displays, will lead
to utilization in lightweight and lower power applications.
Xerox has
had significant activity in developing this technology for some
time. Although not yet perfected, the technology is currently
at the state where it is suitable for development for the first
set of applications. They are currently engaging partners in
both manufacturing and application areas and see a bright future
for this technology.
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