In CRT technology, what is the role of the phosphor screen?

The phosphor screen in CRT (Cathode Ray Tube) technology serves a critical role by emitting light when it is struck by electrons. When the electron beam, generated by the cathode, is directed towards the phosphor screen, the electrons collide with the phosphor material. This interaction causes the phosphor to become excited, resulting in the emission of visible light. This light is what ultimately forms the image that is visible on the screen. The types of phosphors used can vary, which allows for different colors to be emitted depending on the composition of the phosphor material used.

The other roles mentioned, such as storing digital data or modulating the intensity of the electron beam, do not pertain to the function of the phosphor screen. Instead, the phosphor screen's primary and defining function is to convert the energy from the electron beam into visible light, which is fundamental to the operation of CRT displays.