Surface Acoustic Wave (SAW)
Glass, piezoelectric transducers
Principle of Operation
- Piezoelectric transmitters on the sensor generate acoustic waves on the surface of the glass substrate on alternating X-axis and Y-axis patterns.
- The acoustic waves are reflected by a pattern of edge ridges directing the energy to piezoelectric receivers.
- A touch to the surface of the sensor causes attenuation to a portion of the wave corresponding to touch position.
- Touch location is based on the time delay from the transmitted pulse to the center of the attenuation area of the wave.
Pros and Cons
|Touch activated by bare finger, some gloves, or soft conductive stylus
|Moving liquids or solid particles of contaminants may cause false touches or areas without touch function until they are completely removed
|Light transmission typically 92 %
|Dirt and water seal can be difficult
|Typically wide border
|Limited to 1 resolvable points
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