Conductive coatings play an important role in capacitive touchscreens. Whether it’s a smartphone, tablet, human machine interface (HMI) or any other capacitive touchscreen, it will likely have at least one conductive coating. You typically won’t be able to see it. Nonetheless, the conductive coating is essential to a capacitive touchscreen’s operations. To learn more about conductive coatings and how they work in capacitive touchscreens, keep reading.
What Is a Conductive Coating?
A conductive coating is a thin layer of an electrically conductive material or substance that’s added to an existing layer. Most touchscreens are made of multiple layers — and capacitive touchscreens are no exception. In a capacitive touchscreen, some of these layers may feature a conductive coating. Conductive coatings are synonymous with capacitive touchscreens. All capacitive touchscreens, including surface capacitance and projected capacitance, have a conductive coating.
Conductive Coating Properties
For a coating to be considered conductive, it must exhibit a high level of electrical conductivity. What does this mean exactly? A high level of electrical conductivity means that electricity can easily flow through it. Some materials have a low level of electrical conductivity. These electrically resistive materials disrupt the flow of electricity. Conductive materials, on the other hand, allow electricity to easy travel through them.
How Conductive Coatings Work in Capacitive Touchscreens
Most capacitive touchscreens feature indium tin oxide (ITO) for the conductive coating. ITO exhibits a high level of electrical conductivity, making it ideal for capacitive touchscreens. ITO is also transparent. As a result, an ITO conductive coating won’t interfere with the touchscreen’s display quality.
In a typical capacitive touchscreen, the ITO conductive coating is placed over the top layer. When you turn on the capacitive touchscreen, the ITO conductive coating will become electrified. Capacitive touchscreens work by creating a uniform electrostatic charge across the top layer while simultaneously measuring this charge for changes in capacitance. Touching the top layer with a bare finger will cause a change of capacitance. Your finger will absorb some of the stored electrical charge, and the capacitive touchscreen will identify this change as a touch event.
Conductive coatings allow capacitive touchscreens to measure uniform electrostatic fields. Without a conductive coating, a capacitive touchscreen won’t be able to create a uniform electrostatic field. In turn, it won’t be able to measure the charge of this field to detect touch commands. Conductive coatings solve this problem by storing the electricity produced by a capacitive touchscreen.