Ever wonder what capacitive touchscreens are coated with? Capacitive touchscreens don’t feature a plain glass layer. While most of them do, in fact, feature a glass top glass, they have an invisible coating over this glass layer. Known as a coating, it plays an important role in a capacitive touchscreen’s operations. Most capacitive touchscreens won’t be able to detect touch commands without the right coating.
Why Capacitive Touchscreens Require a Coating
Capacitive touchscreens require a coating so that they can detect touch commands. Not to be confused with resistive touchscreens, capacitive touchscreens are designed to measure changes in capacitance. They apply a voltage to the top layer, which they constantly measure. Any distortion in this otherwise uniform electrostatic field signifies a touch command.
Glass, of course, isn’t conductive. Therefore, if capacitive touchscreens only featured a glass top layer without a coating, they wouldn’t be able to detect touch commands. Manufacturers solve this problem by leveraging a conductive coating. They apply a transparent, electrically conductive coating over the glass top layer. Once applied, it allows capacitive touchscreens to detect touch commands.
Tapping the glass top layer with a bare finger or any other conductive object will change its capacitance. The conductive object will draw some of the voltage through the conductive coating, resulting in a change of capacitance. The capacitive touchscreen will notice this change of capacitance, and it will respond by registering a touch event in the appropriate area of the interface.
ITO Coatings and Capacitive Touchscreens
The most common type of coating for capacitive touchscreens is indium tin oxide (ITO). ITO isn’t a single, specific material. Rather, the term “ITO” refers to a composition of indium, tin and oxygen. These elements are combined to create ITO, which is then applied to the glass top layer of capacitive touchscreens.
Why do capacitive touchscreens use ITO coatings exactly? ITO features several characteristics that make it an excellent choice. For starters, it’s transparent while offering excellent optical clarity. It doesn’t block or restrict light. The light from a capacitive touchscreen’s backlighting can easily shine through an ITO coating.
Not only is it transparent, but ITO is also conductive. It offers excellent electrical conductivity. Conductivity is a measurement of how easily electricity can flow through an object. Capacitive touchscreens require a conductive coating because they rely on capacitance to detect touch commands. Fortunately, ITO works well as a coating thanks to its electrically conductive properties.