Touch Screen

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What Does Touch Screen Mean?

A touch screen is a computer display screen that serves as an input device. When a touch screen is touched by a finger or stylus, it registers the event and sends it to a controller for processing.

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A touch screen may contain pictures or words that the user can touch to interact with the device.

Techopedia Explains Touch Screen

A touch screen has two main advantages. First, it allows users to interact directly with what is displayed, rather than indirectly with a pointer controlled by a mouse or touchpad. Secondly, it does not require the use of an intermediate device. Touch screens can be attached to computers or to networks as terminals. They also play a prominent role in the design of digital appliances such as the personal digital assistant (PDAs), satellite navigation devices, mobile phones and video games.

How a touch screen event is registered depends on the touch screen’s inherent technology. The three main touch screen technologies are:

  • Resistive: This screen has a thin metallic layer that is conductive and resistive, so that touching results in a change in the electrical current sent to the controller. Pros: More affordable, not damaged by dust or water, responds to finger or stylus. Cons: Only 75% clarity and susceptible to damage by sharp objects.
  • Surface Acoustic Wave (SAW): Ultrasonic waves pass over this screen. Touching it results in absorption of part of the wave, registering the position of the touch, which is sent to the controller. Pros: Responds to finger or stylus. Cons: May be damaged by dust or water.
  • Capacitive: This screen is coated with an electrically-charged material. Touching it causes a change in capacitance, which allows the location to be determined and sent to the controller. Pros: Not damaged by dust or water and has high clarity. Cons: Must be touched with a finger only – a stylus cannot be used.

There are other, less-common touch screen technologies. These include:

  • Dispersive Signal Technology: Introduced in 2002 by 3M, sensors detect mechanical energy during a touch. Complex algorithms interpret the data to determine the location, and data is sent to controllers. Pros: Durability, not affected by elements, excellent clarity and finger or stylus may be used. Cons: After the initial touch, the system is not able to detect a motionless finger or stylus.
  • Acoustic Pulse Recognition: This system was released in 2006 by Tyco International’s Elo division. It uses transducers located around the screen to transform vibration into electrical energy via algorithms that determine location. Pros: Good durability and clarity, resistant to the elements and well-suited to large displays. Cons: Cannot detect a motionless finger.
  • Infrared: Detects touch via an array of light-emitting diodes (LEDs) and photo-detector pairs at the edge of the screen. Pros: No damage by elements, a finger or stylus may be used, highly durable with high clarity.
  • Optical Imaging: Image sensors (cameras) placed at the edge of the screen pick up infrared black lights on the opposite side of the screen. Pros: Scalable, versatile, affordable and can be used for large displays.
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Margaret Rouse
Editor

Margaret jest nagradzaną technical writerką, nauczycielką i wykładowczynią. Jest znana z tego, że potrafi w prostych słowach pzybliżyć złożone pojęcia techniczne słuchaczom ze świata biznesu. Od dwudziestu lat jej definicje pojęć z dziedziny IT są publikowane przez Que w encyklopedii terminów technologicznych, a także cytowane w artykułach ukazujących się w New York Times, w magazynie Time, USA Today, ZDNet, a także w magazynach PC i Discovery. Margaret dołączyła do zespołu Techopedii w roku 2011. Margaret lubi pomagać znaleźć wspólny język specjalistom ze świata biznesu i IT. W swojej pracy, jak sama mówi, buduje mosty między tymi dwiema domenami, w ten…