Wednesday, November 3, 2010

Combining multimodal touch and haptic response


Haptic effects

In the development of the Fuse handset, the design needed to accommodate a “floating” touchscreen. That is, rather than being rigidly bound to the outer case of the handset, the touchscreen needed a small amount of lateral compliance to allow for crisper and more responsive touchscreen haptic feedback. To overcome any apparent compliance or “mushiness” in the screen, the engineers developed specially designed mounting grommets to provide the lateral support for the touchscreen.

Capacitive sensors suit this type of suspended design as they can be appropriately calibrated to trigger on contact, as compared to resistive touchscreens, which require greater pressure (see Fig. 2). This also supports pressure sensors, and multi-stage haptic effect triggering where different haptic effects come into play, depending upon the size or length of the capacitive touch.

Fig. 2. Capacitive-touch sensing technology (left) lends itself more easily to integration with haptic and other sensing than traditional resistive touch sensing (right).

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