GB867276A - - Google Patents

Abstract

867,276. Photo-conductive cells. EASTMAN KODAK CO. March 19, 1958 [March 19, 1957], No. 8877/58. Drawings to Specification. Class 37. In a method of manufacturing photoconductive cells, metal electrodes are deposited on a flat glass surface having a groove in it, a portion of the groove being masked. The mask is then removed and photo-conductive material deposited in the groove on the previously masked surface and on the inner edges of the electrodes. The excess photo-conductive material and electrode metal is then removed from the flat surface of the plate by fine grinding or lapping. The size of the cell being determined by the width of the groove and the width of the original masking. The cells may be made singly, in rows, or in arrays. If made in an array, further masking is required to separate cells adjacent to one another in the same groove. In order to keep the outer ends of the electrodes clear of photo-conductive material, to allow the external connections to be made, they may be masked or, alternatively, the photo-conductive material after being applied to the surface may be covered, in the areas where it is to be retained, by a material resistant to a solvent of the photo-conductive material the excess material then being removed from the outer ends of the electrodes by the solvent. The resistant material may be applied, by painting or vacuum evaporation through a suitable mask, either before or after the fine grinding or lapping referred to above and may be left on the finished cell as a protective layer in which case it must be made of a material transparent to the radiation to which the cell is required to respond. Materials. The electrodes may be of gold evaporated on to the glass by a vacuum coating technique and the photo-conductive layer may be of selenium, lead sulphide, lead selenide or other suitable material applied by known methods, e.g. chemical precipitation or vacuum evaporation.