Touchscreens and Tablet PCs

Pointing at something you want is a natural way to communicate. Young children often point accurately and with understanding long before they can react in other ways. Bright, noisy computer programs can provide the stimulus needed by children and people with special needs. However, a mouse may require too much motor skill and switches may be too indirect. Touch monitors operate with standard mouse operated programs and provide the most direct input method of all. The user watches the screen and uses it as an input method. There is a direct connection between action and result. (Words: Inclusive Technology)

What is Touchscreen ?

A touchscreen is a combination of a computer monitor and an easy-to-use input device. Using a touchscreen, a user can operate devices such as PC’s, communication devices, public terminals, etc., without a keyboard, mouse or any other input device. To make selections, user presses buttons that appear on the screen directly by using fingers, pointing pens or even toes and prostheses. The surface of the screen is touch-sensitive and can provide the computer with information on the exact location on the screen where a touch was made – very much the way a mouse sends signals to the computer.

Touch Screens

Image Source:
LS800 Pro Tablet PC


Touchscreens can be used as assistive devices by users who lack skills to use classic computer equipment. With touchscreens, use of devices becomes more natural, intuitive, and user-friendly.

How the technology actually works > . . .

Note that not all types of touchscreens react when not touched with bare skin (capacitive type requires a conductive input) and that there are differences in picture quality (surface acoustic wave type is best).

There are three types of touch screen technology (Source:CIO-Midmarket):

  • 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.

Comparing touch technologies > . . .

Touchscreen Overlays

It is also possible to put a "Touch Window" over the front of a standard monitor to give the same function as illustrated in the picture below. A lightpen is a similar idea, requiring you to hold a pen and point it at the screen.

A touch screen kit includes a touch screen panel, a controller, and a software driver. The touch screen panel is a clear panel attached externally to the monitor that plugs into a serial or Universal Serial Bus (USB) port or a 'bus' card installed inside the computer. The touch screen panel registers touch events and passes these signals to the controller. The controller then processes the signals and sends the data to the processor. The software driver translates touch events into mouse events. Drivers can be provided for both Windows and Macintosh operating systems. Internal touch screen kits are available but require professional installation because they must be installed inside the monitor. (Source:CIO-Midmarket).

Touch Overlay Window with Software

Touchscreen overlay kit
Touchscreen overlay image

More about Touchscreen overlays > . . .

Touchscreen Technologies

Touchscreen iMAC

HP IQ500 TouchSmart PC.

Asus Eee Top touchscreen PC

The latest offering from Asus. It has a 15.6" Single Touch Panel and a 1.3 megapixel webcam, plus built-ib microphone, speakers and Wi-Fi.

Asus Eee Top touchscreen

(Image source:

Asus Eee Top demo

Asus Eee Top Review

Hands on with the HP TX2z

Touchscreen panels for Monitors

Dell Studio One 19

Microsoft Surface

Microsoft Surface is a new technology that has recently been released

The video illustrates the power of multitouch technology where you can activate more than one area of the screen at a time

3D Interface with Touchscreen

3D desktop imageXgl is a new Xserver architecture layered on top of OpenGL. Xgl can perform intricate graphical operations--such as rendering antialiased fonts--noticeably faster than other available Xservers that do not use OpenGL.

More important than speed alone, Xgl accelerates complex composite operations, making possible new stunning visual effects.

These visual effects have broad practical use, making Linux more accessible for the visually impaired, and creating a workspace that is easier to comprehend and navigate for less experienced users. More about SUSE Linux desktop . . .

TouchScreen Suppliers & Resources

Tablet PCs

What is a Tablet PC?

Tablet Tutorial Part 1

Tablet Tutorial Part 2

Tablet Tutorial Part 3

Apple MacBook Tablet

Touchscreen Software

Herbi - FREE handwriting software for Touchscreen - helping children to write

Don't forget the new iPad !

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