Natan Linder, a researcher at MIT's Media Lab , asked a question most of us have never thought to ask: what if the lamp on your desktop could be transformed into a computer display?

Instead of screwing a lightbulb into a spring-armed desk lamp, Linder designed a device that combines a camera, digital projector, and wireless node. LuminAR (the AR stands for "augmented reality") works on the same 110 volts that would have powered the lightbulb. The result is one of the coolest demos I've seen in a long time: a personal projector that can turn any flat surface into a rough approximation of an iPad.

"People work with objects all day long, like the stuff on our desk  not just things in the digital world," Linder says. "So we think that objects and surfaces should also become interactive, offering you relevant information." The goal of the LuminAR project, he says, was "to build a new form factor for a computer that wasn't screen-centric or keyboard-based."

Imagine having a second screen on your desk that could let you scroll through last month's invoices as you sought the answer to a customer's question, or a "sales assistant" at an electronics store that could identify the mobile phone you've placed on the counter, and show you information about its features.

LuminAR communicates wirelessly to a computer tucked away beneath the desk. The camera and built-in depth sensor allow it to see hand gestures and objects, and the display splashes a full-color image onto any surface. Linder has built robotic versions of Luminar that can rotate and "zoom in" on their own, making the projected image larger, as well as versions that you move manually.

"You might want to do a Skype videoconference on the table, without worrying about booting up your computer or finding a headset," Linder says. "That's the way computation should be  more like using the microwave in your kitchen, and less like using a computer."

So far, Linder has built six LuminAR prototypes using a pico projector from Microvision; one was shown at the National Retail Federation Convention earlier this year, as part of Intel's "Connected Store" concept display. "We showed a way to bring the online shopping experience to the counter of a store like Best Buy," Linder says. "You might want to videoconference with an expert to ask questions about a particular product, or see the batteries and SIM cards and printers that are compatible with the product you're looking at."

Linder, who previously worked in R&D at Samsung and was an entrepreneur-in-residence at Jerusalem Venture Partners, says he doesn't have any immediate plans to try to commercialize LuminAR. (He's focused on finishing his thesis.) But there has been a lot of interest from big companies, he says. "Banks are very interested, as a way to show their customers what the teller is doing on that screen behind the glass," Linder says.

Linder believes that after the mobile and tablet computing waves, we'll see more interfaces built into our environments. As he puts it, "the world is next."

Here are two videos that show different LuminAR prototypes.

Engadget and MIT wrote about Linder's project last year.