| 摘要 |
<p>PURPOSE:To obtain a photoelectric screen having sensitivities even to waves longer than those to which the usual photoelectic screen is sensitive by introducing potassium over the photoelectric screen. CONSTITUTION:A plate-like anode 5 for forming a photoelectric screen 4 on the inner wall of the first bottom surface 3 of an airtight case 2 consisting of a glass wall, is installed. The photoelectric screen 4 is elecrically connected to a lead-in wire 11 through a chromium layer 6. The anode 5 is electrically connected to a lead-in wire 17. In order to form the phoptoelectric screen 4, silver is vapordeposited on the inner wall of a face plate 3 from a silver particle 7 after a tube 1 is evacuated, then pure oxygen is introduced into the tube 1 before the oxygen gas is subjected to electric discharge in a high-frequency electric field thereby oxidizing the thin silver film. Next, a potassim case 9 is heated by feeding current to it so as to cause emission of potassium thereby adsorbing potassium on the above silver layer. Then cesium is caused to be emitted from a cesium case 10 thereby causing adsorption of cesium. After that, silver is again vapordeposited on the photoelectric screen. The thus manufacture photoelectic screen has a sensitivity to white light of 40-45muA/lm and an improved sensitivity to infrared rays of around 7-8muA/lm.</p> |
