Introduction to Touch Screen Systems
A touchscreen is an input device that allows users to operate a PC by simply touching the display screen. Touch input is suitable for a wide variety of computing applications. A touchscreen can be used with most PC systems as easily as other input devices such as track balls or touch pads.
How a Touchscreen Works
A typical touchscreen input system is basically an input device like a mouse or trackpad. A touchscreen system is made up of a touch sensor, a controller card, and a software driver. These components work together to make an interactive touchscreen system.
What are the Touchscreen used for
Touchscreen systems are being used in a variety of applications, including
point-of-sale systems, public information displays, industrial control
systems, and more. We will give you additional examples of how touch
technology is being used today.
Comparing Touchscreen and Display Technologies
The touch screen is not a new technology. There are traditionally four major types of touch screen input devices - Resistive, Capacitive, Surface Acoustic Wave (SAW) and Infrared. All of these technologies have their own distinct characteristics, with both advantages and disadvantages.
Resistive Technology
Resistive touch screen technology is recommended for use in POS (Point of Sale): Grocery Stores, Hotels, Restaurants and Retail Stores; Industrial Applications: MMI (Man Machine Interface), Machine and Process Control; Portable Devices; Personal Information Management Systems; Transportation Solutions; Medical Solutions: Equipment, Instrumentation
Resistive is the most common type of touch screen technology. It is a low-cost solution found in many touch screen applications, including hand-held computers, PDAs, consumer electronics, and point-of-sale-applications.
Capacitive Technology
Capacitive touch screens are all glass and designed for use in ATMs and similar kiosk type applications. A small current of electricity runs across the screen with circuits located at the corners of the screen to measure the capacitance of a person touching the overlay. Touching the screen interrupts the current and activates the software operating the kiosk.
Because the glass and bezel that mounts it to the monitor can be sealed, the touch screen is both durable and resistant to water, dirt and dust. This makes it commonly used in harsher environments like gaming, vending retail displays, public kiosks and industrial applications.
However, the capacitive touch screen is only activated by the touch of a human finger and scratches in the coatings can cause dead spots on the screens. A gloved finger, pen, stylus or hard object will not work. Hence, it is inappropriate for use in many applications, including medical and food preparation. The technology was originally created for small screens and will not scale to larger screens easily and can require periodic recalibration
Surface Acoustic Wave (SAW)
SAW touch screen technology is suggested for use in ATMs, Amusement Parks, Banking and Financial Applications
SAW technology provides better image clarity because it uses pure glass construction. A SAW touch screen uses a glass display overlay. When sound waves are transmitted across the surface of the display:
Each wave is spread across the screen by bouncing off reflector arrays along the edges of the overlay
When the user touches the glass surface, the user's finger absorbs some of the energy of the acoustic wave and the controller circuitry measures the touch location.
Infrared
Infrared technology relies on the interruption of an infrared light grid in front of the display screen. The touch frame or contains a row of infrared LEDs and photo transistors, each mounted on two opposite sides to create a grid of invisible infrared light.
Infrared touch screens are often used in manufacturing and medical applications because they can be completely sealed and operated using any number of hard or soft materials.
The major issue with infrared is that the seating of the touch frame is slightly above the screen. Consequently, it is susceptible to early activation before the finger or stylus has actually touched and surface. Contaminants can also cause false activation on the screen inside the thick border that is required for the frame. The cost to manufacture the infrared bezel is also quite substantial. due to all these reasons it is fast getting obsolete.