Touch Screen

A touch screen is a highly sensitive display screen found in computer-related devices and is also considered an input device. It quickly responds to any form of pressure applied on the surface that thereafter, causes signals and/or currents to be sent to the main controller, signaling the execution of certain actions.

There are three types found in the market today and each has its own set of advantages and disadvantages depending on the material used and the process flow applied. The said types are:

A. Resistive – a touch screen coated with a thin metallic electrically conductive layer, which causes a change in the current once pressure is applied. A “message” or alert for action is then sent to the controller. This type is sold at a more reasonable price but only provides 75% clarity. It cannot, however, be damaged by sharp objects or affected by external elements such as water, dust and dirt.

B. Surface Wave – utilizes ultrasonic waves that flow through the surface or screen and is subsequently absorbed when pressure is applied. The exact point or position of contact is transmitted to the controller so as to execute a necessary response or action. It is currently one of the most high-end technologies ever designed and constructed in the development of touch screen systems. However, it is highly sensitive to external elements and may be damaged by dirt, dust and water.

C. Capacitive – consists of two layers of electrodes with the upper containing vertical strips and the lower containing horizontal strips. Once the human finger places pressure on the screen, the mutual capacitance of the two layers change thus, resulting in the transfer of some charges to the user and consequently, making significant differences on the display. The information will then be sent to the PC port.