Ultrasonic waves are sent across the glass panel with the help of transducer and reflector in Surface Acoustic Wave technology. Transducer and Reflector are important elements in SAW. Receiving and transmitting transducers are placed across X and Y-axis of the touch panel. The system controller sends electrical signals to transmitting transducer that converts them into ultrasonic waves. Transmitting transducer emits ultrasonic waves to the edge of the touch screen panel where reflectors are placed. The reflectors convert the ultrasonic waves into electrical signals and send them to system controller.

When a user touches the panel, the ultrasonic waves are absorbed and touch event is detected at that point. This information is sent to the system controller and appropriate action is taken further. Like infrared touch screens, Surface Acoustic Wave technology does not have a number of layers. Surface Acoustic Wave has higher image clarity and light transmission. A finger, glove or stylus can be used to detect the touch event.

Figure showcasing the internal structure surface acoustic wave based touch screen.


Figure showcasing the operation when a finger approaches SAW based touch screen.