Cathode ray tube having an improved cathode

摘要

A cathode ray tube is provided with a phosphor screen (14) and an electron gun (19) including a cathode (40) having an electron-emissive material layer (42) formed on a surface of a cathode base metal (41). The electron-emissive material layer includes a first layer (421) made of an alkaline earth metal oxide on the surface of the cathode base metal, a second layer (422) on a surface of the first layer which is an alkaline earth metal oxide layer containing at least one rare earth metal oxide in a range of 0.1 to 10 weight percent, the at least one rare earth metal oxide having a specific particle size distribution. The cathode base metal is made chiefly of nickel and containing at least one reducing agent, and a thickness of a portion of the cathode base metal in contact with the electron-emissive material layer is in a range of 0.10 to 0.16 mm. <IMAGE>