Microsoft Files Patent for Wireless Charging Pad

Microsoft filed a patent application for a wireless charging pad for portable devices, which could become a useful accessory for both smartphones and tablet PCs. Other companies, including Palm and Nokia, have either released or been experimenting with wireless charging docks. Microsoft's patent describes a device that can charge other electronics with the speed and efficiency of traditional "cord equipped" chargers. In conjunction with hardware partners, Microsoft has been planning tablet PCs, and possibly a branded smartphone, that could benefit from an accessory such as a wireless charger.

Microsoft issued a patent application on Feb. 18 describing a wireless charging pad for portable devices, in a hint of what the company could be thinking as it moves more aggressively into both the smartphone and tablet PC space.

"A charging device as described herein can utilize a sensor-integrated resonating circuit with automatic frequency control to prove low-cost inductive charging functionality for electronic devices," reads the patent's abstract. "Further, a charging device as described herein can have an inductive charging surface as well as a non-charging surface for providing other services such as information display."

In essence, the patent sets out to solve what it describes as a particular issue: "Wireless charging techniques typically provide low efficiency and slow charging speeds as compared to comparable wired charging solutions." In addition, such devices are also expensive and require a form-factor too large to easily "fit inside a portable device."

Other manufacturers have been dipping their toes into the wireless-charging space. In May 2009, Palm announced that the Pre would debut with a wireless charging pad dubbed the "Touchstone," which utilized electromagnetic induction to power devices and retailed for $69.99.

Nokia researchers have also been reportedly experimenting with ways to charge mobile and wireless devices, aiming to eventually create a device that collects up to 50 milliwatts of power, enough to charge a cell phone that has been turned off. However, those researchers also suggested that such technology could potentially be years away from mainstream manufacture.

Microsoft's patent describes a device capable of efficiently charging other electronics via "a sensor-integrated resonating circuit with automatic frequency control to provide low-cost inductive charging functionality for electronic devices." In theory, that would make the device as efficient and speedy as its cord-equipped equivalent.

A wireless charging pad could potentially dovetail with other rumored areas of Microsoft research. According to a recent report by Northeast Securities analyst Ashok Kumar, Microsoft could release a branded smartphone running its new mobile operating system, Windows Phone 7 Series, at some point in 2011; even if that rumor never pans out, other whispers about Microsoft developing a branded device under the umbrella of "Project Pink" have been circulating for some time. As Palm demonstrated with the Pre, there is utility for a wireless charger.

Microsoft has also been moving with hardware partners such as Hewlett-Packard to introduce a series of tablet PCs running Windows 7 throughout 2010 and into 2011. Those tablets would function as both multimedia devices and e-readers, and compete against Apple's upcoming iPad tablet. Microsoft CEO Steve Ballmer unveiled three tablets, including HP's "Slate," during his Jan. 6 keynote address at the Consumer Electronics Show (CES) in Las Vegas.

A charging pad, particularly one with a screen, could become a vital accessory for future tablet PCs, as well. As with many patents filed by tech companies, though, the document could more represent an attempt to lock down an idea than a genuine research initiative.