Capacitive touchscreen devices are found everyone. Whether you’re familiar with the technology or not, you’ve probably used a capacitive touchscreen device. Android and Apple iOS smartphones, for example, use capacitive touch-sensing technology. Tablet computers and human machine interfaces (HMIs) are also powered by the same capacitive technology. And while there are different ways to design a capacitive touchscreen device, most feature four basic layers, which we’re going to explore in this blog post.
#1) Polyester-Coated Layer
The uppermost layer of a capacitive touchscreen device typically features a polyester coating with a conductive material underneath. The conductive material is essential because it allows the device to measure changes in capacitance. When you touch it, your body will absorb some of the device’s current, thereby allowing it to identify the location of your touch command.
#2) Spacer Layer
Below the polyester-coasted layer in a capacitive touchscreen device is a spacer layer. As the name suggests, this is an inert layer that doesn’t offer any real functionality. Rather, it contains adhesive that holds together the other adjacent layers.
#3) Glass Layer
Following the spacer layer, the third layer in a typical capacitive touchscreen device is the glass layer. It’s made of glass with a conductive material coating on the top. Like the polyester-coated layer, the conductive material is important because it allows the device to pass an electrical charge. The capacitive touchscreen devices creates a small, uniform electrical charge that travels through these layers and to the surface of the outermost layer. Without conductive material on the polyester-coated layer or glass layer, a device’s electrical charge wouldn’t reach the human user. Therefore, it wouldn’t be able to identify the user’s touch commands.
#4) Adhesive Layer
The fourth and final layer in a capacitive touchscreen device is the adhesive layer. This layer is designed primarily for mounting. It contains adhesive on the backside that allows it to “stick” to the rest of the device.
To recap, a typical capacitive touchscreen device has four layers, including a polyester-coated layer, a space layer, a glass layer and an adhesive layer. These layers work harmoniously so that the device can identify the user’s touch commands. Upon touching the uppermost layer, the polyester-coated layer, your finger will absorb some of the device’s current. It’s not enough to cause pain or even notice, but the device can measure this otherwise subtle change in capacitance — and this is the basis on which all capacitive touchscreen devices operate.
