In glow discharge, the Townsend third ionization coefficient is two electron emission coefficients of the cathode surface under ion bombardment, this process is generally the auger and neutralization process of ions on the cathode surface (auger Neutralization of an ion), also known as Hagstrum theory (see also: Homer D. Hagstrum, germ of Auger Ejection to Electrons by Ions, "Phys. Rev. 96, (1954) 336 – 365). When the positive ions move to the cathode surface, the free electrons in the cathode material are compounded and the ionization energy is released, and the other electrons in the cathode obtain the ionization energy, overcome the surface barrier and release from the cathode, which is called two electron emission, which is an indirect field emission process. At the same time, positive ions in the cathode surface near the formation of a positive ion cloud, the positive ion cloud relative to the cathode as a positive field, there is also a direct field of emission. Therefore, CCFL can be either DC or AC driven.
Because the light transmittance of liquid crystal is very low, the brightness of the LCD TV will reach a perfect display. Backlight lamp brightness is very high, so the life of the backlight lamp is the life of LCD TV, the general LCD TV backlight life of more than 50,000 hours. That is, if you use an average LCD TV for 5 hours a day, the 50,000-hour lifespan equals you can use the LCD TV for 27 years.