PURPOSE: To realize a longer life by performing the degassing of a phosphor screen in advance with electrons accelerated by a higher voltage than the operative voltage of an image tube and then performing the degassing after assembly of the tube to remarkably suppress residual gas.
CONSTITUTION: A phosphor screen bulb 101 is placed on a mounting base D, and in the case where electrons E from an electron gun 20 are brought to be incident upon a phosphor screen 14, an acceleration voltage for the electrons E can be set to a higher voltage than the operative voltage of an image tube regardless of the dielectric strength of a tube body since only the bulb 101 is objective. And for instance the degassing of the phosphor screen 14 is performed with the electron accelerated by a voltage of 10KV being brought into collision with the phosphor screen 14. Next, after degassing, the bulb 101 is taken out from a vacuum chamber 16 and then a sealing flange 10 and the corresponding sealing flange are bonded by arc-welding and further MCP is provided to form a tube body. After that, the degassing process after assembly of a tube is performed, thereby making it feasible to remarkably suppress a residual gas, so that an image tube which has a phosphor screen and a longer life may be manufactured.
ICHIKAWA KOZO
TSUCHIKAWA MINORU
