Microsoft has been granted a patent relating to the use of buttons on hardware devices that form part of a user interface.

US Patent 6,727,830, granted April 27, is described as a "time-based hardware button for application launch." The patent abstract goes on to explain that the patent relates to how different functions can be invoked depending on whether a button is clicked once, clicked and held down for a period of time, or double-clicked within a short period of time.

A Microsoft spokesman confirmed that the patent was granted by the Patent and Trademark Office to Microsoft and that it was developed by employees working in the company's Pocket PC group. He couldn't say whether or not the patent applied to desktop applications, or how Microsoft planned to enforce the patent.

The patent mainly concerns handheld computing devices that come with a set of application buttons, according to the patent description:

"In the past, the actuation of an application button caused an application to be launched in a particular state, for example a view state. The user was required to take further steps to invoke additional application functionality, such as opening a document. It is desirable to more-easily launch applications in various states. The present invention is directed to increasing the functionality of application buttons so as to accomplish this result," the patent reads.

Jeff Norman, an intellectual property partner with the Chicago law firm Kirkland Ellis said that the patent appeared to cover "the time dimension to a click."

"Depending on how long you hold the button, that would define a different set of applications," he said. "It could be used, for example, in a voice recorder. Instead of launching the application, the voice recorder software could know to begin recording if the user clicked and held down on the click."

FAT chance
Late last year, Microsoft began demanding royalty payments for the use of its FAT (file allocation table) system, for which it was granted a patent in 1996. A group called the Public Patent Foundation in April called for that patent to be revoked, claiming that this amounted to an abuse of monopoly power by Microsoft.

"Microsoft is using its control over the interchange of digital media to aid its ongoing effort to deter competition," the group said. "The patent is causing immeasurable injury to the public by serving as a tool to enlarge Microsoft's monopoly while also preventing competition."

(Robert McMillan in San Francisco contributed to this story.)