Liquid crystal displays include passive matrix liquid crystal display (PM-LCD) and active matrix liquid crystal display (AM-LCD). STN and TN liquid crystal display belong to passive matrix LCD. In 90s, active matrix liquid crystal display technology developed rapidly, especially thin film transistor liquid crystal display (TFT-LCD). As a replacement product of STN, it has many advantages, such as fast response and no scintillation. It is widely used in portable computer and workstations, TV, video camera and handheld video game machines. The difference between AM-LCD and PM-LCD lies in the fact that each pixel with switch devices can overcome cross interference and achieve high contrast and high resolution display. At present, AM-LCD adopts amorphous silicon (a-Si) TFT switching devices and storage capacitor schemes, which can get high gray level and achieve true color display. However, the development of P-Si (polysilicon) TFT (thin film transistor) display has been driven by the demand for high-density cameras and projection applications for high resolution and small image elements. The mobility of P-Si is 8 to 9 times higher than the mobility of a-Si. The size of P-Si TFT is small, not only suitable for high density and high resolution display, but also can be integrated into the substrate. In short, LCD is suitable for small, light and low power small and medium sized displays, which are widely used in notebook computers, mobile phones and other electronic devices. The 30 inch and 40 inch LCD have been developed and some have been put into use. LCD after scale production, the cost is decreasing. At present, the 15 inch LCD monitor has been on the market for 500 US dollars. Its future development direction is to replace the PC cathode display and its application in LCD TV.
Plasma display is a light-emitting display technology realized by the principle of gas (such as air) discharge. The plasma display has the advantage of cathode ray tube, but it is made on thin structure. At present, the mainstream product size is 4042 inches. The 5060 inch product is being developed.
Vacuum fluorescent display is widely used as a monitor for audio / video products and household appliances. It is a three pole electron tube vacuum display device, which encapsulates the cathode, the grid and the anode in the vacuum tube. It is accelerated by the positive voltage added by the grid and anode, and is stimulated by the excitation of the phosphor coated on the anode. The gate is used as a honeycomb structure.
Electroluminescent displays are made of solid state thin film technology. An insulating layer is placed between 2 conductive plates, and a thin electroluminescent layer is deposited. The device uses wide spread spectrum zinc
coated plates or strontium coated plates as electroluminescent parts. The electroluminescent layer is 100 microns thick and can display as clear as an organic light emitting diode (OLED) display. Its typical driving voltage is AC voltage of 10KHz and 200V, which requires more expensive driver IC. A high resolution micro display with active array driving scheme has been developed.