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Surface Capacitive versus Projected Capacitive

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Update time : 2018-07-05 14:50:27

What exactly is a surface capacitive touch screen?  

Surface Capacitive versus Projected Capacitive

A surface capacitive touch screen monitor consists of a touch glass overlay that has a transparent electrode layer that is placed on top of the glass itself and is then protected by a protective cover.  How does the touch function then work exactly?  The touch glass itself reacts to the static electrical transmitted from the human body to the fingertip that touches the capacitive touch glass.  The electrical charge from the touch glass transfers from the touch glass to the user and the decrease in capacitance is detected by sensors that are located from the corners of the screen.  Through this method, the controller is allowed to determine the touch point.  With Surface Capacitive touch screen monitors, the activation points can only be activated through the touch of human skin or a stylus that holds an electrical charge.  With surface capacitive touch, the screen is much more durable, has high scratch resistance and has great resistance against surface contaminants, like dust, grease, water or any other liquid residue.

What makes a projected capacitive touchscreen monitor different from surface capacitive?  

A projected capacitive is very similar to a surface capacitive, but has some added features that make the touch technology a bit more unique.  A projected capacitive touch has the ability to enable multi-touch that can be applicable to certain touch applications.  Since this touch glass has multi-touch capabilities, the touch function works a bit differently.  The touch glass is embedded with transparent electrode films with an IC chip that creates a three dimensional electrostatic field.  When a finger touches the screen, the electrical currents change and the computer is able to detect the touch points to determine the location touched.  Projected Capacitive touch screens are clearer than surface capacitive touch glasses, so there is excellent image clarity.  This type of touch glass is more scratch resistant than that of surface capacitive touch glass and has the multi-touch capability.  Some downsides would include sensitivity to EMI (Electromagnetic Interference) or RFI (Radio Frequency Interference) and activation can only be done with a bare finger or with thin gloves on.

This is basically how each type of touch glass functions and features that are associated.