Apple applies for stylus patents

Apple has applied for two patents relating to stylus input on capacitive touchscreens and other surfaces.

The applications were made in January last year, but only published by the US Patent and Trademark Office (USPTO) on Thursday. One describes a stylus with a possibly-heated conductive tip, where the stylus can be charged when inserted into the touchscreen device for storage.

The second describes a stylus that could be used to write on any surface, with the writing or drawing then appearing on a separate computing device — rather like a Livescribe pen.

Before Apple's iPhone made capacitive touchscreens the norm, the cheaper resistive type of touchscreen was widely used. Resistive screens work through the application of pressure, so were almost always used with a simple stylus.

Capacitive screens work by recognising the electrical charge between a person's finger and the screen, and cannot be used with a traditional stylus — this makes them easier to use on a day-to-day basis, but a lot less accurate.

Apple is not the first company to address the issue of combining the accuracy of a stylus with the nature and ubiquity of capacitive screens. RIM has come up with a hybrid capacitive-resistive screen concept, while HTC's took the magnet-on-a-stick route.

HTC has brought a product to market — the Flyer Android tablet — that includes a functioning stylus alongside the capacitive screen, and other manufacturers such as Wacom have also released capacitive styluses.