TOUCH SCREENS

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TOUCH SCREENS

• A touch screen is a computer display screen that
  is sensitive to human touch, allowing a user to
  interact with the computer by touching pictures
  or words on the screen.

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• The touch screen system is made up of a touch
  sensor, a controller card, and a software driver.
  
• Touch screen systems are being used in a variety
  of applications, including point-of-sale systems,
  public information displays, industrial control
  systems and more.
• There are a variety of touch screens available
  also many various display and technologies
  offered.

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• Touch screens today are frequently used for
  information kiosks, automated teller machines
  (ATMs), airline e-ticket terminals, and customer
  self-service stations in retail stores,
  libraries, and fast food restaurants. Touch
  screens are also the most common means of input
  into personal digital assistants (PDAs).

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• Since touch screens were designed to provide
  user-friendly, intuitive computer access without
  requiring a keyboard and mouse, it logically
  follows that touch screens can be excellent tools
  for people who experience difficulty using
  keyboards and mice because of physical or
  cognitive disabilities

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• Despite advantages to some, however, touch
  screens can present barriers to others, such as
  people with physical disabilities who are unable
  to touch the device, as well as people with low
  vision and blindness, for whom the device
  provides no controls that can be appreciated by
  sense of touch.
• For people who are physically unable to touch
  the device, an accessible product is one that
  allows the individual to enter commands by voice
  or by pressing the controls with a mouthstick,
  headstick, or other similar device (stylus). Some
  touch screens support stylus input, and others do
  not. The difference is in the device's touch
  sensor technology, of which there are several
  common types

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• Resistive touch screens are pressure sensitive,
  so they can be operated with any input device,
  including a gloved hand or stylus. However,
  resistive screens can be easily damaged by sharp
  objects, and they offer only 75 clarity, which
  may create additional problems for people with
  low vision.
• Capacitive touch screens offer higher clarity and
  are more durable, but they do not respond to
  gloved hands or most styluses (the pointing
  device must be grounded).

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• Infrared touch screens can be operated by either
  human touch or stylus. They also provide high
  clarity and durability. They are more receptive,
  however, to false responses (by dirt, flying
  insects, etc.) and do not respond well to users
  whose fingers hover before pressing a control.
• Surface acoustic wave (SAW) is a more advanced
  technology that provides high clarity and
  durability and can be operated by either human
  touch or stylus. This technology, however, is
  considerably more expensive than the more common
  technologies and is not as well supported.

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• People who are blind and some people with low
  vision are unable to locate the controls of a
  touch screen device. These individuals may be
  able to locate and activate controls if they are
  labeled in a large high-contrast font and/or if
  audible output is provided to help identify the
  controls. Audible output is also required for
  users with visual impairments to access the
  information that results from activating the
  controls. The Trace RD Center has conducted
  extensive research into designing touch screens
  that are accessible to people with visual
  impairments.

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