Cathode ray tube screens.

摘要

A cathode ray tube comprises an envelope (1) having a screen (3) of a single crystalline or polycrystalline material such as yttrium aluminium garnet. Dopants such as Tb<3><->, Eu<3><->, Ce<3><-> or Tm<3><-> are implanted to different depths or in different areas (7, 10) of the screen. Annealing the screen removes lattice damage caused by the implanting. Multicolour luminescence is obtained by scanning an electron beam over the differently doped areas (7, 10), or by varying the electron beam energy as it scans.