What is capacitive touch technology? In a nutshell, capacitive touch technology is the type of tech that makes the touchscreen on your cellphone or iPad work via electrical charges, which includes the charges that the human body emits. Basically, there are two types of capacitive touch screens: surface and projective.
A surface capacitive uses sensors of the screen and a layer of film across the surface to detect where your finger touches the screen. This technology has no moving parts and is relatively durable, but it does have low resolution. It also requires calibration during the manufacturing process. For these reasons, it is often used in simple applications, like industrial controls and kiosks.
Projective capacitive technology uses a grid of columns and rows with a separate chip for sensing. This tech has higher resolution than that of its surface counterpart. It also allows for a uses of a stylus, and you’ll often see this in point of sale devices that require an electronic signature. Conductive smudges – usually from wet, sweaty, or sticky fingers – and collected dust can interfere with the performance of the device though.
In both scenarios – the surface and the projective – when your finger touches the screen, a tiny electrical charge is transferred to the finger to complete the circuit, which creates a voltage drop at that part of the screen. This is the reason capacitive screens do not work when you wear gloves – cloth does not conduct electricity, unless, of course, it is fitted with conductive thread. The software in the device takes the voltage drop at the landing location of your finger and processes orders of ensuing actions.
Although new touch screens are under development, capacitive touch screens are the industry standard. One of the biggest challenges of touch screen technology is creating large screens – the screen’s sensing capabilities can be affected by their larger electrical fields. There’s a lot more that goes on behind the glassy display of your favorite devices, and soon this technology will be an even bigger part of your everyday living.