While many electronic paper developers are working to develop a new low-power technology and improve its capability to achieve both color and video, Pixel Qi has taken a unique approach and reversed the process to attain its goal. The company has started with traditional liquid crystal display technology, which already provides high-quality color saturation and video switching speeds, and looked to tweak the components to achieve low power consumption and sunlight readability. Headquartered in San Bruno, California - and in Taipei, Taiwan - Pixel Qi was founded by Mary Lou Jepsen, the inventor of the sunlight readable display of One Laptop per Child (OLPC) and co-inventor of its low-power management system.
Innovative LCD Screen
Dr. John Ryan, COO and VP, Marketing of Pixel Qi, discussed with us his thoughts on the company’s mission, strategy and technological expertise.
“We targeted the screen, rather than doing a new laptop for example, because we know how to do significant innovations in LCD screens,” said Ryan. “What inspired us is this … the LCDs in notebook computers today are designed as if they were little TVs: bright, fast, power-hungry, and without great resolution. Our observation is that much of what people do and want to do with their portable computers is actually reading (and writing) and so the portable devices need great resolution for text, lower power consumption, attuned for use in all ambient light conditions, etc. To do this, we’ve redesigned the entire LCD screen.”
LCD Manufacturing Processes
In addition, the company has taken their concept a step further and committed to developing a screen that can be produced using already-in-place LCD manufacturing equipment and processes. According to Ryan, the screens are based on LCD technology - same materials, same processes, made in the same factories … but using an entirely new optical design through the display to achieve performance attributes far from what has been achieved before. “So, it’s rather like achieving really new performance points with (for example) the internal combustion engine for a car, or standard silicon chip technology - rather than designing an entirely new engine technology or deciding to use something other than silicon,” he noted.
All Ambient Light
The company is introducing displays-called 3Qi- that will operate in three different settings. The first is a full-color, bright conventional LCD mode; the second a low-power, reflective e-paper display that will be readable in sunlight; and finally, a low-power basic color transflective mode. The screens are available in 10.1-inch sizes, and soon will also be available in 7.5-inch sizes. A typical LCD screen in 10.1″ consumes 2.5 watts with the backlight fully on; Pixel Qi’s is the same. However, the Pixel Qi LCD screen consumes 0.4W to 0.8W with the backlight off; typical LCDs have totally black screens with the backlight off, but the 3Qi screen moves into an e-paper mode. “This low-energy consumption is a major attribute, along with high resolution,” explains Ryan. “These screens have (for black-and-white reading applications) far more pixels available than any other screen…and not just ‘sunlight readability’ but usability in ALL ambient light conditions.” He explained that most users prefer to use the screen in intermediate mode settings with just a little backlight, preserving much of the power saving while relying maximally on ambient light.
In terms of the competition, Ryan observes that most e-paper technologies have poor color performance, resulting in color images that are dim rather than bright with so few deliverable colors that many images are unacceptable to viewers. “Building on LCD as the basis of the color images solves those problems,” he said. Moreover, the screen refresh times run from about 15 msec to about 60 msec compared to a one-second time for electrophoretic screens. This makes a big difference in terms of scrolling text, cursors and the ability to write; it also makes video possible. In terms of color for e-newspapers and magazines, Ryan feels that consumers will accept a trade-off , i.e., less color with higher resolution in exchange for less power consumption and more sunlight readability. Right now, bright color means high power consumption. That is unlikely to change anytime soon. “Our goal is to create a generation of screens, with exceptional readability, enabling lower power … thus supporting most key needs of portable devices,” said Ryan.
The screens go into volume production towards the end of the year, but Pixel Qi would not comment just yet on who will be doing the manufacturing. Regardless, the screens represent a giant step forward towards so many of the attributes that users of mobile devices have been clamoring for…with a potential to be affordable. “Our screens will be less expensive than comparable-sized electrophoretic screens; how this plays into device prices remains to be seen,” comments Ryan. It will be interesting to see what actually develops.
By Linda M. Casatelli
e-paper, pixel qi