Surface Acoustic Wave(SAW) is a classic method for touchscreens based on the frequency change of surface waves, Surface Acoustic Wave (SAW). SAW touchscreens consist of a glass plate that is sonicated from the horizontal and vertical sides.
In the SAW touchscreen, the ultrasound is generated by two transducers and radiated across the screen via sound reflectors. Sensors are mounted on the opposite sides of the sound reflectors to receive the ultrasound. As soon as the glass screen is touched by a finger or a soft object, the sound is partially absorbed and changes in amplitude. From the amplitude change, the controller calculates the XY coordinates of the touch point.
SAW touchscreens can be flat or curved and can be combined with LCD displays and plasma displays. Since their surface is made of glass, they are insensitive to scratches or general wear and tear. They can therefore be used in public information systems, ticket vending machines or other POI systems. SAW touchscreens are available in all possible sizes up to 50" screen diagonal.