Pixel Qi’s low-power displays that can switch between color LCD screens and e-reader-like black-and-white displays was labeled vaporware in 2009.
But the company silenced its critics by offering some hands-on time at the Consumer Electronics Show with the screens that are already in production.
“We are going mainstream in 2010 in millions of units and we are leading with netbooks,” says Mary Lou Jepsen, founder of Pixel Qi.
Conventional LCD screens offer bright, glossy images but consume too much power. The images they display are also not visible in sunlight. It’s one of the reasons electronic paper, a low-power black-and-white display that can be seen clearly outdoors during the day, has become a rage among e-book readers. Pixel Qi promises to bridge both worlds.
Pixel Qi’s 3Qi display operates in three modes: a full-color LCD transmissive mode; a low-power, sunlight-readable, reflective e-paper mode; and a transflective mode, which makes the LCD display visible in sunlight.
The company is currently producing displays in the 10-inch screen size. They will debut on netbooks. Last year, research firm ABI expected 35 million netbooks to be shipped. That makes it easier to predict demand for these devices and produce displays in large volumes for them, Jepsen says. By the end of the year, Pixel Qi’s screens are expected to be in e-readers and tablets.
Here’s a closer look at the screen:
Transmissive mode:
Pixel Qi display’s transmissive mode is similar to how traditional LCD screens work.
An image on the display is composed of millions of individual pixels. Each pixel is divided into three sub-pixels: red, green and blue. Controlling the intensity of light available to each of these sub-pixels helps produce a color image.
Now, each of the subpixels are further divided into transmissive and reflective modes. In transmissive mode, the screen is primarily lit from the rear using a backlight. When the light reaches the LCD panel, it passes through polarizers that allow it to light up the required combination of subpixels.
The resultant reflected light is picked up by the eye. Pixel Qi’s full-color 10-inch screen has a resolution of 1024 by 600 pixels. It almost feels like a conventional LCD display though the colors aren’t as saturated and the image isn’t as vivid.
Still it is a remarkable sight especially when you know that with the press of a button that screen can be transformed into a black-and-white electronic paper display.
At its peak, the Pixel Qi’s display consumes far less power than conventional LCDs. Peak power is 2.5 watts. Turn off the backlight and you can shave 2 watts off, giving you an extremely low-power display.
Reflective mode:
With the press of a button (Fn + F2 key sequence during the demo), the screen switches to a black-and-white display that evokes the E Ink screen seen on the Kindle, Sony Reader and Barnes & Noble Nook.
In the reflective mode, the backlight is turned off and the ambient light hits a layer of mirror on the display that reflects it back completely. The result is a much higher resolution than in the LCD mode and a screen that plays just off the grayscale rather than creating colors.
In this mode, Pixel Qi’s display looks similar to the electronic paper displays. The key point here, the company says, is that in reflective mode though the screen looks and acts like a E Ink display, it still uses the LCD technology and is cleverly engineered it to mimic an E Ink-like feel.
But unlike an E Ink display, even in the reflective mode, Pixel Qi’s display burns power. E Ink displays don’t consume power while you are reading the text on the screen. It just draws power when you turn the page.
Pixel Qi’s display keeps refreshing at 60 Hz per second so it can’t offer the week-long battery life that an E Ink-based reader does. Pixel Qi says it’s working on displays with lower refresh rates (such as 30 Hz and less), but it isn’t there yet.
Transflective mode:
Play Slumdog Millionaire and stand in bright sunlight and you can still get a pretty good idea of what’s going on on the screen. Pixel Qi’s display scores over its rivals because of the transflective mode that allows viewers to use the LCD-like display even in bright sunlight.
Traditional LCD screens tend to go dark when turned on in direct sunshine. Pixel Qi solves the problem by adding a special layer to the display. The layer is a partial mirror since a part of it transmits the light and part of it reflects the light.
“It’s like a typical mirror layer found in most displays but with holes punched out in it,” says Jennifer Colegrove, an analyst with research firm DisplaySearch. This allows for a composite mode where users can adjust the backlight and still see the LCD screen with reasonable brightness.
If the details about how the displays work are a little hazy, then it’s because Pixel Qi has been very tight-lipped about how it has re-engineered traditional LCD displays to create a screen that can operate in three modes. Pixel Qi has filed more than 20 patents around the technology.
The company is now working on creating touch overlays for its displays to turn them into touchscreens, Jepsen says.
Photos: Priya Ganapati
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