Why I favor Mary Lou’s OLPC screen tech over E Ink—at least for MY purposes

By David Rothman

Given a choice between E Ink and One Laptop Per Child‘s screen technology, which might you choose? Well, in case anyone else is curious, I favor the latter because:

1. The OLPC tech is cheaper, at least for now. The  display developed by Mary Lou Jepsen (photo) costs just $35 a screen to make.

2. Yes, her special LCD can glow in the dark, not just be usable in the sun.

3. It’s color, which kids love. I’m still a kid in that way, among others. Judging from the photo, betcha Mary Lou is, too. Makes for more imaginative engineering.

4. The mix of the glow and the reflective stuff can be pretty easy on the eye.

5. Mary Lou’s screen is better for interactive e-books right now. No delay when you’re entering text. Video potential for the same reason. Of course, E Ink in the future will be much more fleet.

The negative of the OLPC screen tech, compared to E Ink, is that it probably eats up more battery power—-which means the gizmos may have to be larger. But in the reflective mode, it’s still far, far ahead of backlit LCDs in the power consumption department.

No single “best” display

Yes, those impressions are from my perspective.

If E Ink is easier on batteries than the OLPC system, even when the latter uses the black and white reflective mode—I’ll welcome facts and opinions from readers, since this isn’t a simple issue!—then many people may prefer E Ink. What if they spend most of their time away from AC outlets. I don’t. Nor am I bothered as much by the several pounds of the OLPC laptop, far heavier than, say, the Sony Reader. Since the OLPC machine is a real computer, not just an e-book reader, I got a lot back for the weight.

Please note that neither screen technology is going away, and I suspect that some companies may offer both, especially now that Mary Lou Jepsen seems eager to commercialize the display technology of her past employer. A Good Thing, by the way. I believe in profit-nonprofit synergy as long as things are on the up and up, which they appear to be in this case, with Mary Lou’s new company paying licensing fees.

A little more background on OLPC tech

More on Mary Lou Jepsen appears in an IEEE publication, with tidbits, too, about her display:

“According to Jepsen, the display her team eventually marshaled into existence requires, depending on the mode, only between 2 percent and 14 percent of a typical laptop display’s power consumption.

The power needed is low enough to be provided easily by a pull cord or other manual means, charging a nickel-metal-hydride battery pack; 1 minute of charging suffices for 10 minutes of use. To save watts, the display can switch between color with the backlight on, in low light, and black-and-white with the backlight off, in sunlight. OLPC’s engineers trimmed battery usage further by, among other things, adding memory to the ­timing-­controller chip, which decides how often a display refreshes. That trick enables the display to update itself continually without using the CPU if nothing changes on the screen.”

And speaking of gizmos: Put buyers first? What a concept, from the New York Times via Mike Cane.