Editing Head-up display (section)

=== Generations ===
HUDs are split into four generations reflecting the technology used to generate the images.
* First Generation—Use a [[Cathode-ray tube|CRT]] to generate an image on a phosphor screen, having the disadvantage of the phosphor screen coating degrading over time. The majority of HUDs in operation today are of this type.
* Second Generation—Use a solid state light source, for example [[LED]], which is modulated by an LCD screen to display an image. These systems do not fade or require the high voltages of first generation systems. These systems are on commercial aircraft.
* Third Generation—Use [[optical waveguide]]s to produce images directly in the combiner rather than use a projection system.
* Fourth Generation—Use a scanning laser to display images and even video imagery on a clear transparent medium.
Newer micro-display imaging technologies are being introduced, including [[liquid crystal displays|liquid crystal display]] (LCD), [[liquid crystal on silicon]] (LCoS), [[digital light processing|digital micro-mirrors]] (DMD), and [[organic light-emitting diode]] (OLED).