Though you may not be aware of it, the technology already exists to create a video screen thin enough -- and flexible enough -- to fit seamlessly into the pages of this magazine. Ultrathin electronic devices can be built using a special inkjet printer that squirts fine layers of complex compounds instead of ink. When the compounds dry, they leave behind sheer metallic films, which in the right combination could act as thermometers, light sensors, even computer chips. So why haven't you seen these gadgets yet? In part because they are hard to power: even the smallest lithium-ion watch battery is too bulky. The solution is to print batteries too. This year, a research team at the Fraunhofer Research Institution for Electronic Nano Systems revealed a 0.6-millimeter-thick battery. It consists of a stack of metal pastes that act as anode, cathode and electrolyte, bound on top and bottom by carbon layers that collect electricity and deliver it to the attached device. This product can be built right into the device it's powering, as part of the production process, so there's no need for an additional assembly line. And the battery can be made as large or as small as needed, simply by printing more of it. The list of possible applications is endless -- from bandages that release medication when they sense an increase in body temperature to wallpaper that changes color at the flick of a switch. We're not talking megawatts, of course. According to Andreas Willert, one of the researchers, it takes about 15 square centimeters of printable battery to provide the same power as a single watch battery. But 15 square centimeters could be enough to power, say, a blinking magazine cover for a month. The Fraunhofer Research Institution introduced its battery at a nanotech expo in Japan in February. The next step is to open a small production line, which Willert expects will be ready next year. Which means that soon, instead of reading these pages, you might be watching them.