Surface Acoustic Wave (SAW)

A SAW touch screen consists of a piece of glass with "sound wave reflectors" deposited along all four edges. Two emitting transducers are mounted in two corners and receivers are mounted in the opposing two corners. A sound wave travels parallel to the borders of the glass. As it encounters the sound wave reflectors, some of it is passed through to the next sound wave reflector, and some of it is reflected across the touch screen. On the opposite side, the wave is passed through the sound wave reflectors to the receivers. The receivers can detect a drop in amplitude of the sound wave when a sound absorbing material (such as a finger) is placed in contact with the glass.

SAW technology is great for public-use applications, such as the following:

• Point-of-information kiosks
• Electronic catalogs
• Gaming, lottery, and amusement
• Multimedia marketing
• Banking/financial transactions
• Ticket sales/transportation
• Multimedia pay phones
• Industrial control rooms