Speicherelektrode fuer Bildaufnahmeroehren und Verfahren zu ihrer Herstellung

摘要

A photo-sensitive device contains a porous layer of photo-conductive material in contact with a semi-porous layer of photo-conductive material. In a vidicon-type camera tube this composite layer may be formed directly on the transparent signal electrode or on an intervening layer such as a thin solid layer of the same or a different photo-conductive material. As particularly described a 1" diameter disc of glass or quartz, which is to be the face-plate of a camera tube, is provided with a translucent electrode by spraying its hot surface with a solution of a tin salt. The disc is placed at 25-40mm from a boat containing antimony trisulphide and a 1-2m layer of the sulphide vapour deposited in an argon atmosphere having a pressure of 1mm Hg. Since the mean fee path of the antimony trisulphide is about 0.05mm the molecules are able to form relatively large aggregates before reaching the substrate so that a porous layer is formed. A 0.5 m layer of the sulphide is then deposited at an argon pressure of 0.03mm Hg. in which the mean fee path of the photo-conductor is about 1.5mm. Smaller aggregates are thus formed and a semi-porous layer is produced. During production of the composite photo-conductive layer a mask is used to prevent deposition around a peripheral zone of the disc where it is to be bonded to the tube. The invention may also be applied to tubes when the composite layer is deposited in situ.