What are the main types of touchscreen technologies used in Touch Panel PCs, and how do they differ?

The three dominant touch technologies in Touch Panel PCs are resistive, capacitive, and infrared.

Resistive touchscreens consist of two flexible layers separated by a small gap. When pressure is applied (by finger, stylus, or gloved hand), the layers make contact, registering a touch. They are cost-effective, highly durable against dust and liquids, and can be operated with any object, making them ideal for industrial settings with heavy debris. However, they offer lower optical clarity and only support single-touch input.

Capacitive touchscreens, most commonly projected capacitive (PCAP), use a grid of electrodes that sense the electrical properties of a conductive object (like a human finger). They support multi-touch gestures, have superior brightness and clarity, and are highly responsive. They are the standard for consumer devices but are more expensive and can be less reliable in wet or heavily gloved environments, though specialized gloves and enhanced sensors are now available.

Infrared (IR) touchscreens place an array of light-emitting diodes and photodetectors around the bezel. An interruption of the infrared grid detects touch. IR technology offers excellent optical clarity, supports multi-touch, and works with any input method, including thick gloves. Its main drawbacks are higher cost, sensitivity to ambient light interference, and vulnerability to dirt accumulating on the bezel.