PURPOSE: To obtain uniform cathode uniformity by depositing and forming a photoelectric surface forming substance accumulated on the photoelectric surface and the forming substance accumulating surfaces of metallic plates on an inner wall of an incident surface plate.
CONSTITUTION: Sb is deposited over one surface part of each half-etched metallic plate 15 and 16 by a fixed quantity by resistance heating. Mn is deposited similarly over by a fixed quantity. one surface part of each metallic plate 17 and 18 Next, a square shape mesh electrode 14 is installed on a focus disk 12. The metallic plates 17 and 18 are heated and Mn films 17a and 18a formed on the upper surfaces of the metallic plates 17 and 18 are all evaporated. After evaporation is finished, O2 is introduced, and an MnO film is formed on an inner wall of an upper surface plate of a vacuum container 11. Next, the metallic plates 15 and 16 are heated, and Sb films 15a and 16a are all evaporated. After evaporation finished, alkaline metal is introduced, and is activated, and a photoelectric surface 19 is formed. Thereby, the Sn and Mn are hardly evaporated on an upper surface of the focus disk 12 or a surface except the upper surface plate of the vacuum container 11 such as the side surface of the vacuum container 11.
NAKAMURA MAKOTO
ISHIKAWA YOSHIKUNI
Next Patent: SIGNAL RECORDNG AND REPRODUCING DEVICE