Touchscreen technology is now used in countless applications, only one of which involves consumer electronics like smartphones and tablets. While there are plenty of touchscreen-compatible mobile devices, you can find them in other places like retail point-of-sale (POS) systems, manufacturing control systems, human machine interfaces (HMIs) and more. The exact construction of a touchscreen device varies depending on its intended application as well as the type of touchscreen technology powering it. With that said, most touchscreen devices contain a few basic components, including the following.
The overlay layer is the outermost layer on a touchscreen device. It’s designed to protect the device’s underlying components from damage. The overlay layer prevents physical stress or moisture from penetrating through the touchscreen device, which could otherwise cause permanent damage to the device.
In addition to an overlay layer, touchscreen devices also have a touch controller. The touch controller is a small circuit — or a printed circuit board (PCB) in many touchscreen devices — that converts data from the touch sensor into information that’s readable by the touchscreen device’s operating system (OS) or software. Without a touch controller, a touchscreen device wouldn’t be able to properly register a user’s touch commands.
Not to be confused with a touch controller, a touch sensor is a touchscreen component that, as the name suggests, is used to detect touch commands. There are different types of touch sensors, each of which uses a different method of operation.
With that said, capacitive touchscreen devices contain a touch sensor that emits an electrical charge across the surface of the device. This creates a uniform electrostatic field that the touch controller measures while looking for changes in capacitance. If a user touches the surface of the device, his or her finger will absorb some of the electrical current, resulting in a reduction of capacitance. The touch controller then recognizes this change in capacitance, identifying it as a touch command.
Finally, touchscreen devices require the use of an electronic display, with liquid crystal displays (LCDs) being the most common. LCD is often preferred for touchscreen applications over other display technologies because of its superior resolution, refresh rate, efficiency and longevity.
These are just the basic components of a typical touchscreen device. Of course, all touchscreen devices also require software to function. When speaking strictly about hardware, though, touchscreen devices typically have an overlay layer, a touch controller, a touch sensor and an LCD.