Capacitive Touch Screen

The capacitive touch screen is built with an insulator-like glass coating, which is covered with a see-through conductor, such as indium tin oxide (ITO). The ITO is attached to glass plates that compress liquid crystals in the touch screen. User screen activation generates an electronic charge, which triggers liquid crystal rotation.

Capacitive touch screen types are as follows:

• Surface Capacitance: Coated on one side with small voltage conductive layers. It has limited resolution and is often used in kiosks.
• Projected Capacitive Touch (PCT): Uses etched conductive layers with electrode grid patterns. It has robust architecture and is commonly used in point-of-sale transactions.
• PCT Mutual Capacitance: A capacitor is at each grid intersection via applied voltage. It facilitates multitouch.
• PCT Self Capacitance: Columns and rows operate individually via current meters. It has stronger signal than PCT mutual capacitance and functions optimally with one finger.

Other touch screen technologies include resistive, surface acoustic wave (SAW) and infrared (IR).