GB1115319A - Photocell array structure - Google Patents

Abstract

1,115,319. Photo-cells. D. H. BALDWIN CO. 4 April, 1966, No. 45239/67. Heading H1K. The linear photo-cell array shown has a glass or ceramic substrate 40 bearing interdigitated comb electrodes 46, 47 and, between adjacent prongs of opposite combs, a series of individual electrodes 48. A single photo-conductive layer 49 is formed over the electrode films. In operation, an individual electrode 48 is energized and current flows to adjacent comb prongs and may return for example through the half-windings of a centre-tapped transformer primary. The electrode films may be formed by masked vapour deposition of chromium or by overall deposition and photo-resist etching. Electrolytic deposition may instead be used. Photo-conductive lead sulphide may be deposited from solution. A glass cover-plate (50) may be cemented to the substrate leaving exposed only the contact areas of the various electrodes. Two assemblies of double wire spring clips 52 held in insulating bodies 53 may be used to make connections to the contact areas or alternatively the contact areas may be coated with iron and handsoldered connections applied preferably with the aid of a multiple jig. In an alternative mounting, Figs. 3 and 4 (not shown), a similar photo-cell array, with no cover-plate, is inverted to receive light through the substrate. The contact areas of the electrodes are met by double spring fingers (61, 62) bonded by epoxy resin (66) into an insulating channel (65). The array and contact assembly may be placed in a sealed enclosure. In a further construction (Figs. 5 and 6, not shown) the electrode films are deposited so that their contact areas meet iron-cobalt-nickel alloy pins (68) which project from the back of the substrate to be contacted by a spring finger assembly. The facing edges of a glass cover-plate and of the cell substrate are provided with superposed chromium and iron films so that the two may be readily soldered together. Lugs (73, 74) on a metal rim bonded to the free face of the cover locate the cell array relative to an apertured plate in a musical instrument. A modified cell array (Figs. 7, 8, 9, not shown) incorporates a substrate with rounded edges and has the photoconductive layer and prong portions of both comb and individual film electrode on one face of the substrate and has the contact areas of all electrodes on the other face, the prongs being carried round the edges of the substrate.