Touchscreens are used in thousands of commercial and consumer applications. They are the primary input component for nearly all smartphones and tablets. Along with mobile devices, touchscreens are used in human machine interfaces (HMIs), smart appliances, smartwatches, computer monitors, infotainment systems and more. In this post, you’ll learn more about the parts in touchscreens and how they work.
All touchscreens have a touch sensor. The touch sensor is a component that, as the name suggests, is designed to detect or “sense” touch commands. How does the touch sensor work exactly? Touch sensors work in different ways depending on the specific technology used by the touchscreen device. Capacitive touchscreens — the most common type of touchscreen device — use a capacitive-based touch sensor. They emit a small electrical charge across the touch sensor layer. When you press your finger on it, you’ll change the electrical charge of the touch sensor layer.
Capacitive touch sensors detect touch commands by looking for changes in the electrical charge of the touch sensor layer. The human body conducts electricity. Therefore, touching the touch sensor layer will change its electrical charge. Your finger will essentially increase its capacitance, which the capacitive touchscreen will identify as a touch command.
Touchscreens are manufactured of multiple layers. Depending on the type of touchscreen, these layers may consist of tempered glass or plastic. In resistive touchscreens, the layers have electrodes on their opposite-facing sides. Performing a touch command will press the layers together so that the electrodes make contact with each other.
Touchscreens also have a touch controller. The touch controller is located in the middle of the touchscreen. It sits behind the touch sensor and in front of the device’s computer. The touch controller is designed to convert analog touch signals into digital touch signals.
Without a touch controller, a touchscreen wouldn’t be able to respond to your touch commands. The touch sensor may detect your commands, but the touchscreen can only process them if there’s a touch controller present. The touch controller takes the analog signals created by your touch commands, and it converts them into digital signals that the device can understand.
Most touchscreens have a computer as well. Even small touchscreens like smartphones are built with a computer. The computer is found in the very back of a touchscreen. It’s not just a single part. Rather, it consists of multiple parts. Most computers used in touchscreens have a central processing unit (CPU), storage drive and random access memory (RAM).