In the United States, the company has successfully patented the use of short, long or double clicks on the same button to launch different applications on devices such as PDAs.
Microsoft has been granted a U.S. patent on using short, long or double clicks on the same button to launch different applicationsthough only on "limited resource computing devices" such as PDAs or mobile phones.
Now, U.S. companies that use such a variety of clicks on one button to launch separate software functions will have to change their products, pay licensing fees to Microsoft or give Microsoft access to their intellectual property in return.
U.S. patent No. 6,727,830,
awarded April 27, was built on an abandoned 1999 application and filed in 2002.
It relates to a "time-based hardware button for application launch," specifically assigning additional functions to application buttons when, for example, they are held down for longer than usual or clicked multiple times.
The examples used in the patent relate to Microsofts handheld computers, but the company says the patent could extend to devices such as mobile phones and pagers.
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The patent describes ways that application buttons on a "limited-resource computing device" such as a PDA can be used in different ways to trigger various effects.
For example, pressing a button for a short period of time could launch an application in its default view, while pressing the same button for a second could launch an alternative function, such as bringing up a particular document within the application.
"Yet a third application function can be launched for a multipress [e.g., double-click] of an application button," the patent says.
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One of the patents specifications is for a voice-recorder application: The device begins recording when the button is pressed and stops recording when the button is released.
The patent could be applied to a wide range of devices and systems, Microsoft says in the document: "The invention can be incorporated in other limited-resource devices and systems, for example, mobile devices such as pagers and telephones."
And the invention isnt necessarily restricted to the added functions specifically described in the patent.
"While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention," Microsoft states in the document.
The patent doesnt seem to apply to double-clicking a PC mouse, but could affect a wide range of other devices, a legal expert said. "This could have some impact beyond just PDAs," said Mark Watts, IT partner at London-based law firm Bristows.
He noted that the processing power of handheld devices such as PDAs and smart phones is approaching that of laptop computers, while some PC devices now use dedicated application buttons.
"Prior art" claims could invalidate the patent, but theyre costly.