E Ink

E Ink

(E Ink Corporation, Cambridge, MA, www.eink.com) Founded in 1997, E Ink makes electronic paper display (EPD) subsystems for handheld devices using E Ink Vizplex Imaging Film. Although initially monochrome, color is expected in 2010. Products using the film include seven-segment display modules for small devices such as smart cards, shelf labels and wristwatches, and partially complete substrates for larger screens in e-book readers and similar-sized devices.

Long Battery Life, High Resolution and Flexible
EPD screens can run from 10 to 30 times longer than LCD screens without recharging. Unlike LCD electronics, which need constant refreshing, once an EPD display is rewritten, it holds its content indefinitely.

The resolution of EPD devices in production is 167 dpi, compared to 96-120 dpi on LCD screens. Since EPD supports up to 400 dpi, the resolution limitation is in the device electronics. In 2008, Epson revealed an EPD prototype at 385 dpi, displaying 3104 x 4128 pixels on a 13.4" screen.

E Ink's seven-segment displays are made on plastic backplanes, and although the larger substrates are made on glass, they are expected to be made on plastic in the future for flexible applications.

Microcapsules Filled with Fluid and Particles
The E Ink Vizplex film is made of microcapsules filled with fluid and many charged black and white particles composed of ink pigments. The microcapsules are coated on the film and laminated to the top electrode. Row and column drivers are attached, and the module is shipped to customers who add the bottom electrode. Sandwiched between the electrodes, the black and white particles are drawn to the viewing surface when the opposite charge is applied.

The EPD technology stems from the early 1990s when Dr. Joseph Jacobson of MIT Media Labs improved upon an earlier approach from Xerox PARC that used larger beads and considerably more power. E Ink Corporation was founded to refine the MIT technology. See electronic paper and electrophoresis.

Opposites Attract

The charged particles are attracted to the opposite charge on the electrodes, drawing them to the appropriate side. Up to 16 shades of gray are produced by switching the field with varying durations at the pixel location, causing the black and white particles to mix.

Great for E-Book Readers

Along with other e-book readers, Amazon's Kindle uses E Ink's technology for its display. The long battery life is a significant advantage of the electronic paper display (EPD). (Image courtesy of Amazon.com, www.amazon.com)

As Sharp as Paper

In 2008, Epson demonstrated a super-high-resolution prototype display using E Ink technology. At 385 dpi, this 13.4" display provides an outstanding 3104 x 4128 pixel resolution. (Image courtesy of Seiko Epson Corporation.)