(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. Initially only monochrome, color E Ink displays were introduced in 2010. Products include seven-segment display film for smart cards, shelf labels and the like and partially complete substrates for e-books.
Long Battery Life, High Resolution and Flexible
EPD screens can run up to 30 times longer than LCD screens without recharging. Unlike LCDs, 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 (see image below). E Ink's seven-segment displays are made on flexible plastic backplanes, and the larger glass substrates are expected in plastic in the future.
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 more power. E Ink Corporation was founded to refine the MIT technology. See electronic paper and electrophoresis.
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.
Amazon's Kindle uses E Ink displays with the significant advantage of long battery life (see
To celebrate Esquire's 75th Anniversary in 2008, a limited edition of the magazine was printed with an animated E Ink cover. To view the cover on the newsstand, visit www.esquire.com/the-side/video/e-ink-cover-video.
In 2008, Epson demonstrated a super-high-resolution E Ink prototype. At 385 dpi, this 13.4" display provides an outstanding 3104 x 4128 pixel resolution. (Image courtesy of Seiko Epson Corporation.)
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