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.
- Touch activated by bare finger, some gloves, or soft conductive stylus
- Transmission typically >90%
- Moving liquids or solid contaminants may cause false touches or non-touch areas until completely removed
- Dirt and water seal can be difficult
- Typically wide border
- Limited to 1 or 2 resolvable points (depending on manufacturer)