TOUCH SCREEN TECHNOLOGY AND TYPES OF TOUCH SCREENS
A touchscreen is an easy to use input device that allows users to control the system by touching the display screen. A touch system consists of a touch sensor that receives the touch input, a controller, and a display unit. The most commonly used touch technologies are the capacitive and resistive systems. The other technologies used in this field are infrared technology, near field imaging and SAW (surface acoustic wave technology).
These technologies are latest in this field but are very much expensive. A little note on resistive and capacitive touchpad is as follows.
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.
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.
Touch Screen Technology essay
Touch screen technology is a kind of input innovation that allows people to manipulate a computer system by simply touching the terminal display screen. Touch screen technology is adapted for a wide variety of e-business and personal application, such as public information display, customer self-service, control and automation systems, computer based training, and personal entertainment. Touch ...
The graphic LCD that we have used here is OMG12864. It is a 126×64 pixel graphic LCD module having inbuilt controller. A LCD consists of a liquid-crystal material that behaves electrically as a capacitor. There is a set of two transparent panels with a liquid crystal solution between them. Light is shined from behind the panels. Each crystal either allows light to pass through or blocks the light. The configuration of the crystals forms the image.
The two transparent panels are polarized, which means they will only pass light waves in one plane. These two polarized panels are at 90 degrees to each other so that light filtered from one plane cannot get through the other panel because it only lets light through in a plane at 90 degrees to the first plane. So the panel appears to be black or very dark. However, when electricity is applied to one of the segments of liquid crystals, the crystals line up in such a way as to make the light turn through 90 degrees in between the two panels, hence forming the image.
