Touch screen
Image via Wikipedia

A typical touchscreen input system is basically an input device like a mouse or trackpad. If counting as a definition, a touch screen is a computer display screen that is sensitive to human touch, allowing a user to interact with the computer by touching pictures or words on the screen.


A touchscreen system is made up of a touch sensor, a controller card, and a software driver.


Touch screens are used with information kiosks, computer-based training devices, and systems designed to help individuals who have difficulty manipulating a mouse or keyboard. Touchscreen systems are being used in a variety of applications, including point-of-sale systems, public information displays, industrial control systems, and more.  There are a number of types of touch screen technology:


A resistive touch screen panel is composed of several layers. When some object touches this kind of touch panel, the layers are connected at certain point which registers a touch events and sends it to the controller for processing. Resistive touch screen panels are not affected by dust or water and are the type most commonly used today. RESISTIVE


A capacitive touch screen panel is coated with indium tin oxide that conducts a continuous electrical current across the sensor. When the sensor’s normal reference state is altered by someone’s finger, electronic circuits measures the resultant ‘distortion’ and informs the controller for processing. Capacitive sensors can either be touch with a bare finger or with a conductive device. Capacitive touch screens are not affected by outside elements and have high clarity.


Surface acoustic wave (SAW) technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This information is sent to the controller for processing.



This method uses an array of vertical & horizontal IR Sensors that detect the interruption of a modulated light near the surface of the screen. Infrared touch screens are used in many military applications that require a touch panel display.


In this, the screen is spring mounted on the four corners and strain gauges are used to determine deflection when the screen is touched. This technology can also measure the third dimension. This is typically used in exposed public systems such as ticket machines due to their resistance to vandalism. There are several other technologies like Optical imaging, Dispersive Signal Technology, Acoustic Pulse Recognition, Frustrated total internal reflection and Diffused laser imaging.

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