Infrared (IR) and Projected Capacitive (PCAP) are the two most common types of touch screen technologies. Although you may not be able to tell the difference when using an interactive touch screen unless you know how to identify which is which, they are quite different in structure and design. Below we’ll break down the difference between the two to give you better idea of why one might be better than the other for whatever purpose you may be buying or renting your touch systems for.
Projected Capacitive Touch Screens
PCAP touch screen software is typically used in smart phones and tablets, but can also be used for much larger screens. It works through the use of a conductive grid that recognizes changes in its electromagnetic field by the touch of your finger. Projected capacitive touch screen technology does not require a bezel. They detect only fingers or styluses. PCAP displays very accurate, and capable of up to 60 touch points.
IR touch technology involves an embedded overlay of infrared beams from top to bottom and side to side around the device’s bezel. When the invisible plane provided by the beams in broken by any object, the device registers a touch point. With up to 40 simultaneous touch points, IR touch screen displays are a bit less accurate than PCAP displays. That said, Infrared displays are still quite accurate enough to be used in a wide variety of settings. But when used outdoors on a bright and sunny day, the sunlight can sometimes interfere with the overlay’s touch reception.
Working principal of IR and PCAP technology
Projected capacitive touch panels are often used for smaller screen sizes than surface capacitive touch panels. They've attracted significant attention in mobile devices. The iPhone, iPod Touch, and iPad use this method to achieve high-precision multi-touch functionality and high response speed.
The internal structure of these touch panels consists of a substrate incorporating an IC chip for processing computations, over which is a layer of numerous transparent electrodes is positioned in specific patterns. The surface is covered with an insulating glass or plastic cover. When a finger approaches the surface, electrostatic capacity among multiple electrodes changes simultaneously, and the position where contact occurs can be identified precisely by measuring the ratios between these electrical currents.