ABSTRACT
The phosphor screens in cathodoluminescent (CL) display devices have provided light images since the cathode ray tube (CRT) was invented in 1897. CRTs are well-established display devices that serve as an interface between the human eye and electronics devices that record information from modern life activities. This is because image pixels in a phosphor screen emit approximately 10
photons
s
cm
, which is comparable to the number of daytime scenes that human eyes have adjusted to for 7 million years. The large number of photons from CL phosphors is due to the high energy conversion efficiencies of CL phosphors (20% for ZnS), which were optimized in the 1970s both theoretically and practically. Furthermore, CRTs display the images on phosphor screens with low power consumption (30 W per total screen area) using a scanning electron beam of high density. That low power consumption is a great advantage over LCDs and PDPs. Power consumption of the LCD backlight would be 350 W to obtain comparable image luminance. The images on phosphor screens are acceptable to viewers who watch the images at a distance of 5 times the screen size.
