Haptesthai! Sounds Greek to you? Touch technology or more scientifically speaking, haptic technology is derived from the Greek word 'touch'. Sam Hurst at The University of Kentucky developed the world's first 'touch sensor' in 1971. This technology has come a long way, with applications not limited to the cool phones that you see everywhere.
Ever wonder how touch screens work? Touch screen technology has 3 components namely, a touch sensor, a controller and a software driver. The touch sensor is a clear glass panel placed over a display screen. This responds to your touch through a system of electrical signals that pass through it. When the screen recognizes the touch, there is a change in the electrical current or signal. This change helps in detecting the location of the touch. There are many ways by which touch screens perceive touch. Take a look at the following:
Resistive: Consists of a glass panel that is covered by a metallic layer which is both conductive and resistive
These 2 layers are held apart using something called spacers. To cover the entire setup is a scratch resistant layer.
Electrical current is passed when the monitor is switched on
The two layers make contact when the user touches a point on the screen
Touch creates a change in the electrical field and this information is then sent to the computer
Capacitive:
There is a layer that stores electrical charge. This layer is directly placed on the monitor.
User touches the screen
The layer with electrical charge loses some of the stored electrical charge. This difference in the electrical charge is then calculated and the information is then transmitted to the touch-screen driver software
Surface acoustic wave: On the glass monitor, there are 2 transducers which send and receive information. These are placed along the x and y coordinates of the screen. The glass has reflectors placed on them. These reflect electrical signals between the transducers. The receiving transducer can detect a change in the wave detected because of touch.
After the screen has recognized the touch, this information has to be transmitted to the computer in a way that the machine can understand. This is accomplished through a small PC card that connects the screen to the computer. The controller does this part of the process.
And finally, touch screens have a software driver which helps the touch screen and the computer to work together.
What you just read is a very simplified story of how touch screens work. But the next time you see a touch screen phone or an ATM, you'll have a better understanding of how these marvels do what they do.
