Photosensitive element having photoconductive layers

Claim 1

A PHOTOSENSITIVE ELEMENT COMPRISING A HOST PHOTOCONDUCTIVE MATERIAL, SAID ELEMENT HAVING AN ELECTRICAL CONDUCTIVITY RESPONSIVE TO LIGHT AND HAVING A PRE-DETERMINED PEAK SPECTRAL RESPONSE WAVELENGTH AND BANDWIDTH DIFFERENT FROM THE PEAK SPECTRAL RESPONSE WAVELENGTH AND BANDWIDTH OF THE HOST PHOTOCONDUCTIVE MATERIAL, SAID ELEMENT COMPRISING A PLURALITY OF SEPARATELY DEPOSITED, SUCCESSIVELY PHOTO-SENSITIZED LAYERS OF HOST PHOTOCONDUCTIVE MATERIAL , EACH OF SAID LAYERS BEING IN THE FORM OF THIN PLATELETS HAVING A UNIFORM THICKNESS OF BETWEEN ABOUT 1.5 AND 4.5 MICRONS AND A SURFACE AREA WHICH IS LARGE IN COMPARISON TO THE THICKNESS, THE LAYERS BEING SUBSTANTIALLY COTERMINOUS IN SURFACE AREA, AND AT LEAST ONE SURFACE OF EACH OF SAID LAYERS BEING IN IMMEDIATE, INTIMATE AND SUBSTANTIALLY OVERALL PLANAR CONTACT WITH A SURFACE OF ANOTHER LAYER, THE HOST PHOTOCONDUCTIVE MATERIAL IN EACH LAYER BEING PHOTO-SENSITIZED BY A HALOGEN. THE HOST PHOTOCONDUCTIVE MATERIAL IN EACH LAYER BEING A COMBINATION OF AT LEAST TWO SUBSTANCES, ONE OF SAID SUBSTANCES BEING SELECTED FROM THE GROUP CONSISTING OF CADMIUM, ZINC, MERCURY AND MIXTURES THEREOF, THE OTHER OF SAID SUBSTANCES BEING SELECTED FROM THE GROUP CONSISTING OF SULFUR, TELLURIUM, SELENIUM AND MIXTURES THEREOF.