Electronic Design
Multitouch Functionality Comes To Bigger Screens

Multitouch Functionality Comes To Bigger Screens

Large multitouch displays with fancy graphics are the rage on TV shows. Even local weather reporters use multitouch interfaces. Bringing the technology to the masses, though, is still a challenge.

Smaller devices like the Apple iPhone and Motorola Droid have multitouch support and have been shipping in the millions. But in this case, small has its advantages. The release of Apple’s iPad (Fig. 1) has sparked interest in larger form factors (see“Success Of iPad Is All About Software”).

Mid-range all-in-one PC platforms like HP’s TouchSmart also employ multitouch technology. The TouchSmart PC (Fig. 2) product line is based on a 23-in. HDTV display with multitouch support, but the platform commands a premium price. Touch support is only one aspect of the cost, yet it provides one of the more obvious benefits of the all-in-one configuration.


Single-touch detection is common these days, and low-end micros can easily handle it. Multitouch for small devices like smart phones is typically limited to two or maybe three touch points simply because the surface is so small and usable by only one hand. Large screens on the order of 50-in. displays have the potential for more interaction, raising the number of contacts much higher.

New technology from Displax addresses this arena with a mesh of nanowires to implement a projective capacitive touch-sensing system. This is the same approach used by the iPhone but with a larger form factor. Displax can detect up to 16 touches on display sizes of 30 to 116 in., suiting all of the high-definition LCDs and plasma displays on the market. The actual diagonal range for this technology is 18 cm to 3 m.

The projective capacitive touch sensing detects physical contact as well as near-field positioning. It also can detect air movement when someone blows on its surface. The system can even report the direction and intensity of the air movement.

The ability to handle large screens and more than a couple simultaneous touches means Displax can handle collaboration between multiple people. The near-field position should allow for creative user interaction as well.

The technology initially will be deployed in the form of a film with a USB-based controller. It can be mounted behind or on top of a surface. When it’s mounted behind a surface, the material must be less than 15 mm thick. The film targets flat-panel displays but works equally well for transparent projection screens.

The nanowire technology is not limited to a flat film. It can be applied to almost any non-conductive smooth surface. Imagine a globe with touch detection, as users point to anywhere on the Earth and the system responds with information on the selected location. Just think of the possibilities.


TAGS: Components
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