Laptops

Pixel Qi Readies Battery-saving Laptop Screens

One Laptop Per Child spin-off Pixel Qi on Thursday said it will soon start shipping low-power screens that could increase laptop battery life by up to 50 percent.

The company's LCD (liquid crystal display) screens include technology to absorb natural light sources to brighten screens, said Mary Lou Jepsen, founder and CEO of Pixel Qi. That helps save battery life as it reduces the need for a backlight, which is used to light up conventional laptop screens.

"Instead of cranking up the backlight to fight sunlight or the light of the office overhead fluorescent tubes, we realized we could use the brilliant ambient light in the image itself, saving power," said Jepsen.

A casual laptop user may see laptop battery life jump from three hours to four-and-a-half hours by switching to the light-powered screens, Jepsen said. The new screens will provide full color depth and refresh rates that are comparable to conventional laptop screens.

The screens pull as much ambient light from sources as possible, but the technology may not work effectively for users watching DVD movies in dark rooms, Jepsen said.

"The conventional LCD screens in computers are just miniature LCD-TVs. That's perfect, if all you want to do is watch movies all day, sitting in a darkened room, with the device plugged in," Jepsen said, in an e-mail interview.

Low power consumption of the screen, one of the more power-hungry components on a laptop, could lead to cheaper and lighter laptops, Jepsen said.

"Instead of putting six battery cells into this model, I'll try fewer or use less-powerful cells, making the machine lighter and cheaper, and the battery life exactly the same," Jepsen said.

The small bump in battery life isn't close to Jepsen's previous plans of laptop battery life between 20 and 40 hours. However, Jepsen said Pixel Qi is working to blur the line between the screen and motherboard, which could boost battery life more.

"We'll get to larger power savings later so the screen can enable much longer battery life, but for that we need the manufacturers to make changes in the motherboard, which will come in 2010-11," Jepsen said.

The screens will ship for sampling in a few months and be in laptops by the middle of the year, Jepsen said. Initially, the company will ship 10-inch screens. She didn't name PC makers that would eventually use those screens in laptops.

A variant of Pixel Qi's low-power screen technology was first implemented in OLPC's XO laptops. That effort was led by Jepsen, who formerly was OLPC's chief technology officer and contributed to a patent in low-power screen design.

She stirred up a controversy when she left nonprofit OLPC in 2007 to start the for-profit Pixel Qi, with the goal to create a US$75 laptop using technologies she invented at OLPC. The company is now focusing on development of low-power screens.

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