Unbeknownst to many people, the top layer of a typical touchscreen isn’t made entirely of glass. While most capacitive touchscreens do, in fact, have a glass top layer, they contain other materials, one of which being indium tin oxide (ITO). You generally won’t the see the ITO. Rather, it consists of an thin and transparent layer that’s applied over the touchscreen’s glass layer. Without this ITO layer, though, touchscreens wouldn’t be able to identify or respond to touch commands.
What Is ITO?
ITO is a material consisting of three elements: indium, tin and oxygen. The ratio of these three elements can vary depending on the type of ITO. Some types of ITO, for instance, contain a higher ratio of indium to tin, whereas others contain a higher ratio of oxygen to tin. Regardless, all types of ITO contain indium, tin and oxygen. These three elements are mixed together to create a transparent material known as ITO. The ITO is applied over the top layer of capacitive touchscreens, thereby allowing the touchscreen to function as intended.
How ITO Works in Touchscreens
Why do touchscreens have an ITO layer exactly? As previously mentioned, most capacitive touchscreens have an ITO layer. Capacitive touchscreens are those that detect touch commands by measuring capacitance. They project a uniform electrostatic field across the interface, which they measure while looking for changes in its capacitance. Any touch command performed with a conductive object will cause the capacitance to drop. The capacitive touchscreen will then respond with the appropriate action.
The reason why capacitive touchscreens have a layer of ITO is because it allows for conductivity. Glass, of course, has poor conductivity. Electricity can’t easily flow through glass. Capacitive touchscreens can still use a glass top layer, but it must be coated with a conductive material, which is where ITO comes into play.
ITO exhibits several properties that make it ideal for use in capacitive touchscreens. For starters, it’s conductive. While electrically can’t easily flow through glass, it can flow through ITO. ITO is also transparent. You won’t be able to see the ITO layer on a capacitive touchscreen. With its transparent and conductive properties, ITO is one of the most common materials used for screen coatings on capacitive touchscreens.
ITO is an essential material used in the production of capacitive touchscreens. Consisting of indium, tin and oxide, it’s used as a coating. A layer of ITO will allow capacitive touchscreens to identify touch commands performed with a conductive object.