The CRT technology requires a certain distance from the beam projection device to the screen in order to function. Using other technologies, displays can be much thinner and are known as flat-panel displays . LED and gas plasma work by lighting up display screen positions based on the voltages at different grid intersections. LCDs work by blocking light rather than creating it. LCDs require far less energy than LED and gas plasma technologies and are currently the primary technology for notebook and other mobile computers.
Displays generally handle data input as character maps or bitmap .
In character-mapping mode, a display has a preallocated amount of pixel space for each character. In bitmap mode, it receives an exact representation of the screen image that is to be projected in the form of a sequence of bits that describe the color values for specific x and y coordinates starting from a given location on the screen. Displays that handle bitmaps are also known as all-points addressable displays.