Touchscreen

[#1]

Touchscreen

---

Definition

A touchscreen is a display device that allows the user to interact with a computer by using their finger. They can be quite useful as an alternative to a mouse or keyboard for navigating a graphical user interface (GUI). Touchscreens are used on a variety of devices such as computer and laptop monitors, smartphones, tablets, cash registers, and information kiosks. Some touchscreens use a grid of infrared beams to sense the presence of a finger instead of utilizing touch-sensitive input.

There are three types of touch screen technology:

• 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.

---

References

1. Wikipedia: https://en.wikipedia.org/wiki/Touchscreen