As far as the basic image engine, as many as 18 different technologies are still in use, some dictated by the period of manufacture, all, ultimately, by suitability for their particular application, e.g., land, sea, air, body-worn, and/or man-portable. These technologies encompass the older varieties such as CRT, NVG thermal sight phosphors, electromechanical (EM), and incandescent, to the more modern such as liquid crystal on silicon (LCOS), AMOLED, and biaxial scanning mirror microelectromechanical systems. There are also many flat-panel technologies that have become a mainstay since the 1990s: dichroic and passive matrix liquid crystal displays (dLCD and LCD, respectively), active matrix LCD (AMLCD), thick- and thin-film electroluminescent (EL), plasma, inorganic and organic light-emitting diodes (ILED and OLED, respectively), etc. It is to be noted that CRT, EM, and incandescent technologies combined account for some 13.4% of the existing DoD market. NVG and thermal sight phosphors represent another 16.6%. By contrast, flat-panel technologies account for as much as 69.8% of the DoD market, with LCDs alone being 58.2%. This section provides a basic understanding of the many display technologies currently used in military displays. It is important to remember that the DoD market is in constant transition, and the various percentages are but a snapshot of the market as of our last survey.