Touch screen technology is a technology that allows users to interact directly with the display screen. The display is either an LCD display or an OLED display while the system is usually a laptop, smartphone, or tablet.
What is a touch screen?
A touch screen is an input device that accepts input directly from the monitor. In Addition, is a mobile or computer’s display screen that responds by human touch. It allows users to interact by touching pictures or words on the screen.
Technologies used behind Touch Screen
There are four main technologies that work with different methods of sensing touch.
Resistive Technologies –
Resistive touch screen panels use several thin layers with two main transparent electrically resistive layers separated by thin spaces. The touch creates contact between these two resistive layers completing a circuit.
Surface Acoustic Wave –
The Surface acoustic wave uses two ultrasonic waves that pass over the touch screen panel. When we touch on the panel, a portion of the wave gets to observe. The controller processes the change in ultrasonic waves to determine the position of the event.
Capacitive Technologies –
It consists of an insulator, glass panel with an ITO layer (Indium Tin Oxide). It is of two types one is the project and the other one is the surface. A small voltage is applied to four corners of the screen.
Infrared LED or Optical –
Optical Touch screens or OLED uses infrared LEDs and matching photodetectors. Touching the screen interrupts LEDs. The attached cameras detect reflected LEDs caused by touch. Controllers are able to calculate coordinates from camera data.
Principals to Build a Touch Screen
There were several principles to build a touch screen. The main objective was to recognize one or more fingers touching the display to interpret the command and to communicate the command to the appropriate device or application.
The first and most popular technique of touch screen – the resistive technology works on four layers:
- The top layer coated with polyester, with a transparent metallic conductive coating on the bottom.
- Adhesive spacer
- Glass layer coated with the transparent conductive coating on the top
- Adhesive layer on the backside of the glass for mounting.
When we touch the screen, the system records the change in electrons that flows through the display.
The uniform voltage is generated and given to the first layer.
There are two infrared-based approaches. In the 1st approach array of sensors detect the fingers touching the display, thus interrupting the infrared light beams projected over the screen. The second approach says bottom-mounted infrared cameras record heat from the screen touch.
In each case, the system determines the intended command based on the controls showing on the screen at the time or location of the touch.
The Development of Touch Screen
As the technologies developed, the technology of multi-touch screens emerged. The multi-touch screens facilitated the tracking of more than one finger at the same time and from different users.
With the use of touch screen technologies, its cost is routinely observing in the products that we use and the cost of touch screens is reducing day by day.
Touch screen technologies are booming due to their reliability and are now found in many devices like airplanes, automobiles, gaming consoles, machine control systems. Appliances, and handheld devices like mobile phones, tablets, laptops, or iPhones.
In October 2011, TapSense announced that touchscreens can distinguish which part of the hand is used for input such as a fingernail, fingertip, or knuckle. Its usage is in a variety of ways. For instance, copy & paste commands, capitalizing letters, or to activate different drawing modes, etc.