Touchscreen & their pros or Cons

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

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

Pros:

1.Switch and buttons are not physically required. Device makers can make and modify various input 

    interfaces creatively by software.

2.With multi-touch function, various operations/inputs (eg: zoom-in/zoom-out, rotation) are               possible.

3.Because a user operates an electronic device by directly touching the images on the display he is    seeing, the operation will be intuitive, thus anyone can operate it from first use.

4.The whole unit is space-saving because display and input space are integrated. There is a lot of flexibility in design.

5.Unlike keyboard or physical switch, there will be no dirt, dust, and moisture getting into the spaces between buttons. Thus, it is easy for maintenance.

Cons:

1.Since a display is directly touched, the display may get dirty, then become less-visible. A direct    touch may also cause scratches on the screen that may cause malfunction in some cases.

2.Unlike push-button and mouse, users will not feel "click" when a user input a touch screen, thus  operation may become clumsy sometimes. However, there are certain touch screens that provide "click feeling" when touched.

3.Touch screen is difficult to be operated for the visually impaired. Some creative ways to let them    know where to touch are needed. Sound navigation and/or physical buttons might be helpful in  combination with touch screen.