The smartphone is the Swiss Army knife of the digital era, a pocket-sized vade mecum that does everything you could want. Or just about everything. The same thing that leads to a smartphone’s convenience–its diminutive size–is also the thing that prevents it from being as useful as we’d like. Take, for instance, sharing that hilarious YouTube video with friends at the dinner table. Not everyone can fit huddled around that screen.

But what if there were a way to turn your smartphone into a projector, turning the living room wall into your momentary screen?

A new, tiny lens from Alps Electric might just usher in the era of the smartphone projector. Historically (in very recent history, that is), it has been difficult to integrate a projector into a smartphone for reasons of power consumption and heat generation, as Geek.com points out. Projector components have also been too big to pack into a tiny iPhone or Android device.

Alps Electric’s offering manages to sidestep these issues. For one thing, the FLGS3 Series lens, as it’s called, is absolutely miniscule–occupying less than a cubic millimeter. Alps Electric leveraged a lot of R&D and bundled it together, in the process raising what’s known as the “optical coupling efficiency” of the lens–a measure of light transmission efficiency–up to 73% from 68%. This is key; with a higher optical coupling efficiency, less energy is required for a brighter image, eliminating the need for bulky cooling components.

It should be noted that smartphone projectors aren’t entirely new. Well known, of course, are the so called “pico projectors,” external devices you can plug your smartphone into. But even built-in projectors are not unheard of. Texas Instruments showed off a prototype of one back in 2007; and at CES in 2009, Logic Wireless debuted such a phone, the Logic Bolt. But the Logic Bolt only had two hours of battery life in projector mode. InfoWorld’s Amber Bouman didn’t exactly rave about the device when she wrote, “it just took someone crazy enough to do it.”

Alps Electric’s press release announcing its lens is so focused on the optics of the device that it doesn’t venture to mention battery life (which of course would vary from phone to phone). Still, the hope is that by making it a more efficient projector, it would cut down on heat generation and power consumption.

The main question now is how long it will take for the technology to be refined and made less expensive. Back in January, following rumors that the iPhone 5 might introduce an on-board projector, analysts shot down the notion, citing immature R&D and a lack of consumer demand. Though a total of million devices with built-in projectors are expected to have shipped by the end of 2011, according to DigiTimes’s source, prices are likely to remain high until 2013.

Whether Alps Electric’s innovation will help advance that date by a few months or even a year, it’s too early to say. Either way, if you’re eager to throw those YouTube videos up on a wall anytime soon, you’re going to have to shell out.