How Does a Touchscreen Work?
A basic touchscreen has three main components:
1. Touch sensor
2. controller
3. Software driver.
The touchscreen is an input device, so it needs to be combined with a display and a PC or other device to make a complete touch input system.
Working of Touch Screen
1) Touch screen censor
A touch screen sensor is a glass plate having touch responsive surface. The touch sensor is positioned over a display screen so that the responsive area of the plate covers the maximum viewable area of the video screen. There are number of touch sensor technologies available in the market today, each using a different approach to detect touch input. The sensor has an electrical current or signal passing through it and touching the screen causes change in voltage or signal. This voltage or signal change is used to find out the location of the touch to the screen.
2) Controller
The controller used in touch screen is a small PC card that interconnects between the touch sensor and the PC. Controller takes data from the touch sensor and converts it into information that PC can understand. For integrated monitors, the controller is usually installed inside the monitor or it is placed in a plastic case for external touch add-ons/overlays. The controller is useful to determine what type of interface/connection you will need on the PC. Integrated touch monitors are provided with an extra cable connection on the back for the touch screen.
3) Software Driver
The driver is software for the PC system that permits the touch screen and computer to work together. It tells operating system of computer how to interpret the touch event information that is sent from the controller. Today’s touch screen drivers are a mouse-emulation type driver. This makes touching the screen the same as clicking your mouse at the same location on the screen. This permits the touch screen to work with existing software and provide new applications to be developed without the need for touch screen specific programming. Some devices such as thin client terminals, DVD players and specialized computer systems either do not use software drivers or they have their own in -built touch screen driver.
1) Touch screen censor
A touch screen sensor is a glass plate having touch responsive surface. The touch sensor is positioned over a display screen so that the responsive area of the plate covers the maximum viewable area of the video screen. There are number of touch sensor technologies available in the market today, each using a different approach to detect touch input. The sensor has an electrical current or signal passing through it and touching the screen causes change in voltage or signal. This voltage or signal change is used to find out the location of the touch to the screen.
2) Controller
The controller used in touch screen is a small PC card that interconnects between the touch sensor and the PC. Controller takes data from the touch sensor and converts it into information that PC can understand. For integrated monitors, the controller is usually installed inside the monitor or it is placed in a plastic case for external touch add-ons/overlays. The controller is useful to determine what type of interface/connection you will need on the PC. Integrated touch monitors are provided with an extra cable connection on the back for the touch screen.
3) Software Driver
The driver is software for the PC system that permits the touch screen and computer to work together. It tells operating system of computer how to interpret the touch event information that is sent from the controller. Today’s touch screen drivers are a mouse-emulation type driver. This makes touching the screen the same as clicking your mouse at the same location on the screen. This permits the touch screen to work with existing software and provide new applications to be developed without the need for touch screen specific programming. Some devices such as thin client terminals, DVD players and specialized computer systems either do not use software drivers or they have their own in -built touch screen driver.
Systems used to recognize persons touch:
- Resistive: The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer.
- Capacitive: A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO).
- Surface Acoustic wave: Surface acoustic wave (SAW) technology uses ultrasonic waves that pass over the touchscreen panel.
