RIM details hybrid touchscreen

 

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By Stuart Turton

Posted on 7 Aug 2009 at 16:28

RIM has filed a patent application for a new type of touchscreen that uses both capacitative and resistive technology.

Resistive touchscreens employ two separate layers that register an input when they come into contact, usually after being prodded with a stylus.

Capacitive touchscreens, on the other hand, make use of a conductive material such as indium tin oxide. When a human finger touches the oxide it conducts an electrical charge which the device registers as an input.

Resistive touchscreens have been around for the best part of a decade and while cheap to produce, they aren't terribly sensitive. Capacitive touchscreens only really came into fashion with the launch of the iPhone, and while they are much more sensitive, they don't work with stylus input.

Clearly RIM sees the value of both technologies and, in its patent application, the company describes how the outer of the two resistive layers could be coated in indium tin oxide allowing for capacitive sensitivity.

A single controller circuit would then decide which of the input methods was being used, allowing for handwriting recognition through a stylus, and for for the capacitive sensor to recognise when it was being held up against a face during a call and switch the screen off.