Appliance Design - February 2008 - (Page 21) CONTROLS & SENSORS Acoustic Actuation Fig. 1. An acoustic signal from a touch is captured by a sensor, which is then used to determine the exact location of the touch. M aterials choices for product designers are vast, but often when it comes to touch control the fall back is traditionally glass or plastic, but new acoustic signal processing is expanding those options. Acoustic signal processing has been used extensively in many fields such as oceanography and telecommunications. One of the most recent uses for acoustics is to register a touch. For touch screen and touch control applications using acoustics, there are currently several technologies on the market including 3M’s Dispersive Signal Technology (DST) that determines a touch point by measuring mechanical energy waves within a substrate that were created by a finger or stylus touching a surface and how the waves are dispersed over distance. Algorithms anticipate the “dispersion” effect and interpret the precise touch location. Another example is Tyco Electronics’ EloTouchSystems, which uses acoustic pulse recognition technology. This concept is based on the idea that sound generated by a touch has unique characteristics that can be compared against premeasured characteristics identified for that location. Tyco recently entered into a cross-licensing agreement with www.applianceDESIGN.com Sensitive Object, a Paris-based company, that has developed an acoustic technology dubbed ReverSys. The two companies have agreed to cross-license their intellectual property in the acoustic touch field and to enter into a mutual technology development program. ReverSys is a haptic technology, which means it pertains to touch and the sound waves generated from the touch. In a nutshell, the touch on a control panel creates an acoustical signature that is unique to that exact point in space. A similar touch just a few centimeters away will emit sound waves with a different acoustic signature. ReverSys uses acoustic sensors to capture the “sound,” and determine that sound’s signature, which is the key to determining the exact point of the touch. Each signature relates to a specific touch point and each touch point relates to a specific command, says Marc Vasseur, vicepresident of marketing and business development for Sensitive Object. The technology is based on the time-reversal mirror theory. Much of the development work in this arena was done in the 1990s at the Laboratoire des Ondes Acoustiques, the Paris-based acoustic laboratory of the Centre National de la Rescherche Scientifique (CNRS). Here, Professor Mathias Fink invent- A touch-control technology uses what it hears to determine the user’s needs. by larry adams applianceDESIGN February 2008 21 http://www.appliancedesign.com
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.