An Optical Touch panel has two optical sensors with two reflectors and a light source (LEDs). When an object interrupts the infrared light, the two optical sensors will detect the movement of any object on the screen. The controller can calculate X and Y and then send the position to the computer.
Benefits
Infrared technology touch panel have rows of LEDs and detectors on each edge of the touch frame. Each light emitting diode (LED) sends a light beam to the other side, where ther is a light detector. These light beams become an IR light grid. When the IR light beams are interrupted on any location, the controller will calculate X distance and Y distance and then send the exact position to the computer.
Benefits
The projected capacitive touch screen works on the principle of conventional capacitive touch screens with the addition of two sensing arrays (X and Y) on two different layers that are perpendicular to each other along with a drive line. As X and Y arrays exist on different layers, the point where the two intercept becomes a capacitive node. When electrical currents run along one of the arrays through the drive line, the other array and the circuitry that detects change in capacitive values becomes connected. During actual operation, the controller sends electrical currents to the drive lines on different layers to create a specific electrical field with the nodes.
When the user places his finger or uses a touch medium close to the touch screen, the controller immediately picks up the change in capacitive value between the nodes and drive lines to pinpoint the exact location of the touch event. Since the sensing arrays on the panel form a 3D electrical field that is independent to the surface capacitors, the touch event registers even when no physical contact with the touch screen is made. In other words, projected capacitive touch screens feature Z-axis recognition.
Benefits
The surface capacitive touch screen utilizes the ITO (Indium Tin Oxide) at the touch screen surface to achieve a change in electrical current upon contact with the human body. The change is registered by the sensors placed at the edges and transmitted to the controller as an analog signal. The signal will then be processed by the controller before it is sent to the system as a digital signal to be displayed visually on the monitor.
Benefits