Touchscreens have revolutionized the way in which we control computers, smartphones and other electronic devices. They eliminate the need for traditional peripherals like a keyboard and mouse. Instead, touchscreens allow for touch-based methods of input. There are several different touch-sensing technologies, however, each of which works in a different way.
Resistive is a type of touch-sensing technology that uses two layers of an electrically resistive material to detect touch commands. Resistive touchscreens have two layers that are separated by air. Each of the two layers are made of an electrically resistive material. When you perform a touch command, you’ll push the top layer into the bottom layer, thus allowing for the completion of a circuit.
The most common type of touch-sensing technology is capacitive. Capacitive touchscreens are characterized by their use of capacitance to detect touch commands. They project a uniform electrostatic field across the display interface. Touching the display interface will draw some of this electrostatic field to your body. The capacitive touchscreen will then register this reduction in capacitance as a touch command.
It’s important to note that there are several types of capacitive devices, some of which include the following:
- Surface: features a conductive layer on a single side of the insulator with a voltage being applied to the other layer.
- Mutual: creates a capacitor at the intersection of the grid’s rows and columns.
- Projected: uses artificial intelligence processing to achieve a superior level of accuracy and responsiveness.
Another type of touch-sensing technology is surface acoustic wave (SAW). SAW touchscreens are able to detect touch commands just like resistive and capacitance. They are unique, however, because they use sound waves for this purpose. SAW touchscreens feature ultrasonic-emitting components around the perimeter of the display interface. During use, a SAW touchscreen will blast ultrasonic waves across the display interface. Performing a touch command will create a disruption in these ultrasonic waves, which the SAW touchscreen will detect as a touch command.
There’s also infrared (IR) grid touch-sensing technology. IR grid touchscreens are similar to SAW touchscreens except they use light to detect touch commands. SAW touchscreens use ultrasonic waves to detect touch commands, whereas IR grid touchscreens use light.
Along the perimeter of an IR grid touchscreens are small light-emitting diode (LED) bulbs. These bulbs will beam light across the display interface to a corresponding sensor. If you perform a touch command, you’ll block the light in that area, which the IR grid touchscreen will detect as a touch command.