TOUCHSCREEN TECHNOLOGY

TOUCHSCREEN

A touch screen is a computer display screen that is also an input device. The screens are sensitive to pressure; a user interacts with the computer by touching pictures or words on the screen.

History of Touch Screen Technology

1960s

Historians consider the first touch screen to be a capacitive touch screen invented by E.A. Johnson at the Royal Radar Establishment, Malvern, UK, around 1965 – 1967. The inventor published a full

description of touch screen technology for air traffic control in an article published in 1968.

TYPES

  • Resistive:A resistive touch screen panel is coated with a thin metallic electrically conductive and resistive layer that causes a change in the electrical current which is registered as a touch event and sent to the controller for processing. Resistive touch screen panels are generally more affordable but offer only 75% clarity and the layer can be damaged by sharp objects. Resistive touch screen panels are not affected by outside elements such as dust or water.
  • Surface wave:Surface wave technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Surface wave touch screen panels are the most advanced of the three types, but they can be damaged by outside elements.

Capacitive: A capacitive touch screen panel is coated with a material that stores

  • electrical charges. When the panel is touched, a small amount of charge is drawn to the point of contact. Circuits located at each corner of the panel measure the charge and send the information to the controller for processing. Capacitive touch screen panels must be touched with a finger unlike resistive and surface wave panels that can use fingers and stylus. Capacitive touch screens are not affected by outside elements and have high clarity.

ADVANTAGES

 

 

  • -Touchscreen devices have limited buttons that will possibly break after 3 – 4 years
  • -Touchscreen devices usually have more simple user interfaces Ex. Ipod Apps
  • -Having less or not buttons means that you can put more effort into having a big screen 
  • For the people worried about hygiene, most devices are easy to clean, some are even dirt, dust and grease resistant
  • -For people new or uncomfortable with normal desktops, touchscreens are easy to use helping more people get used to using computers

DISADVANTAGES

  

  • -The screen has to be big enough to be able to touch the buttons without missing
  • -Having a big bright screen and needing massive computing power to run this means a very low battery life
  • -In direct sunlight it is much less effictian and most of the time very difficult to read the screen
  • -If a touchscreen devise were to crash the whole screen would be unresponsive, and because of the lack of buttons revoering it would be very difficult
  • -The screens will get very dirty
  • -You have to be within arms reach of the device
  • -They usually cost more than ordinary divices

PICTURES :

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