METHOD OF INCREASING THE PHOTOCONDUCTIVITY OF A PHOTOCONDUCTIVE POWDER

摘要

1403657 Electroluminescence MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 26 June 1973 [26 June 1972 (2)] 30338/73 Heading C4S [Also in Division Hl] An X-ray image converter comprises a transparent glass substrate 1 bearing a transparent electrode film 2 of SnO 2 , an electroluminescent layer 3 of ZnS powder dispersed in urea resin, a reflective layer 4 of BaTiO 3 in urea resin, an opaque layer 5 of carbon black in epoxy resin, a photo-conductive layer 6 comprising powder of a II-VI compound of enhanced photo-conductivity and an X-ray permeable electrode 7 of vacuum-evaporated Al. Layer 6 may comprise CdSe powder, activated by Cu and Cl, which, with an epoxy resin binder, is suspended in diacetone alcohol and ultrasonically agitated to cause sufficiently rapid flow of the suspension to polish the particles of powder so as to increase their photoconductivity. Alternatively, activated CdSe powder may be suspended in toluene with an ethylcellulose binder and agitated in a domestic liquidizer before being precipitated on to opaque layer 5. CdS and CdS x Se 1-x powders are mentioned, as are Ag and Br activators. Electrode 7 may alternatively be permeable to IR or visible light to produce variant image converters.