By means of electric current flow through a heated thermal evaporator for a vacuum installations unreflecting layers

摘要

An evaporator, heated by the passage of electric current and employed in vacuum metallisation plant, consists of a box fitted with aclosed lid and contg. the material to be evaporated. The two long side walls of the box each have a pattern of outlet holes through which the vapour leaves the box. The box is pref. made from two pieces of sheet metal, one (I) for the box, the other (II) for the lid. Sheet (I) is perforated and slotted so that, after bending, it forms a box base with two perforated side walls and two end walls; tongues on both ends of each side wall are bent so they are together and form terminals for resistance heating of the evaporator. (II) has two tabs sepd. by a slot, on each end of the sheet. When bent, the tabs mate with the narrow ends of the box. The holes in each side wall pref. have a total area 15% of each wall. Used e.g. for the metallisation of very large glass panes which are held vertically, and batteries of the evaporator boxes are employed to cover the large areas involved. Excellent results are obtd. in the deposition of ZnS and Ag.