While the exact number is unknown, industry experts estimate that approximately 3 billion touchscreen devices are sold globally each year. From smartphones and tablets to smart appliances and equipment control systems, countless devices support touch-based input. Unbeknownst to many people, however, is that different touchscreen devices use different types of touchscreen technology.
Surpassed only by capacitive, resistive is a popular type of touchscreen technology. It’s able to detect touch commands using pressure. Touching or tapping the surface of a resistive device forces the top layer to press into a bottom layer, which the device uses to identify the location of your touch command.
Resistive devices are available in 4-, 6- and 8-wire configurations, with 8-wire resistive devices offering the highest level of accuracy and stability.
The most popular and common type of touchscreen technology is capacitive. Capacitive devices detect touch commands using an electrical current. As the device projects an electrical current across the top layer, it measures that current while looking for changes in capacitance. If you touch the surface of a capacitive device, your finger — or a capacitive stylus — will absorb some of the electrical current, allowing the device to detect your touch command.
Surface Acoustic Wave
While less popular than resistive and capacitive, surface acoustic wave (SAW) is a viable option to consider when searching for a touchscreen device. SAW devices are similar to capacitive in the sense that they both rely on “interruptions” from the user to detect touch commands. The difference between them is that capacitive devices look for interruptions in electrical current, whereas SAW devices look for interruptions in acoustic waves.
Also known as acoustic pulse devices, SAW devices project sound waves across the surface of the touch interface, which are measured using micro-sized transducers attached to the edges of the device. If you touch the surface, you’ll disrupt the sound waves, allowing the device to identify your command.
Some touchscreen devices are powered by infrared grid (IR) technology. With IR grid, the device contains pairs of IR light-emitting diodes (LEDs) around the edges. When you perform a touch command, you’ll block the LED light in the area of your touch. As a result, the IR grid device can easily detect where you touched.
To recap, the most common types of touchscreen technology include resistive, capacitive, SAW and IR grid. Each technology has its own pros and cons. So, if you’re looking to buy a new touchscreen device, familiarize yourself with all the technologies listed here.