Capacitive Touch Screen

Capacitive Touch Screen

A capacitive touch screen panel is a sensor typically made of glass coated with a transparent conductor such as indium tin oxide (ITO). This type of sensor is basically a capacitor in which the plates are the overlapping areas between the horizontal and vertical axes in a grid pattern. When the finger touches the conductive coating, a small current is drawn from each corner towards the point of contact. Capacitive touch panel can either be touches with human’s finger, or with a conductive device being held by a bare hand.

The Apple iphone is an example of a product, which uses capacitance touch sensor technology. A controller measures the ratio of the current flow on each corner and calculated the location. It prevents from scratches and abrasions since the conductive layer is covered with a protective coating.

It is a durable technology that is used in a wide range of applications including point-of-sale systems (POS), LCD modules, industrial controls, calculator, electric calendar, and public information kiosks. It has a higher clarity than Resistive technology, but it only responds to finger contact and will not work with a gloved hand or pen stylus unless the stylus is conductive.

Circuiting Rating：5V DC, 35mA
Contact Bounce ：<3ms
Transmittance：90%~>95%
Surface Hardness：≧7
Expectancy：Over 225 million times
Operating Temperature：-20 °C ~+70 °C (20%RH~85%RH)
Storage Temperature：-40 °C ~ +85 °C(10%RH~90%RH)