Photodiode structured photosensitive imaging surfaces, methods and apparatus

Abstract

In an example, a photosensitive imaging surface is provided by an extended photodiode structure.

1 . A photosensitive imaging surface comprising:
 a plurality of layers of semiconductor material forming an extended photodiode structure; and,   barriers formed in one layer of the plurality of layers that act to block optical radiation transmission and charge transfer through the one layer.   
     
     
         2 . A photosensitive imaging surface as in  claim 1 , wherein the barriers comprise trenches formed through the semiconductor material of the one layer. 
     
     
         3 . A photosensitive imaging surface as in  claim 1 , wherein the barriers comprise barriers formed in multiple layers of the plurality of layers, the barriers configured to block optical radiation transmission and charge transfer through each layer in which they are formed. 
     
     
         4 . A photosensitive imaging surface as in  claim 3 , wherein the barriers formed in the multiple layers comprise trenches formed through the semiconductor material of the multiple layers. 
     
     
         5 . A photosensitive imaging surface as in  claim 4 , wherein the trenches extend completely through the one layer of the multiple layers and only partly through another layer of the multiple layers. 
     
     
         6 . A photosensitive imaging surface as in  claim 2 , wherein the trenches are filled with a dielectric material. 
     
     
         7 . A photosensitive imaging surface as in  claim 1 , wherein the plurality of layers comprise:
 a first layer comprising n-type doped semiconductor material;   a second layer on top of the first layer and comprising an intrinsic semiconductor material; and,   a third layer on top of the second layer and comprising p-type doped semiconductor material.   
     
     
         8 . A photosensitive imaging surface as in  claim 1 , further comprising a low electron mobility layer on top of the extended photodiode structure. 
     
     
         9 . A photosensitive imaging surface as in  claim 1 , further comprising on top of the extended photodiode structure, a layer with refractive index lower than a refractive index of the extended photodiode structure. 
     
     
         10 . A method comprising:
 applying an electric field to a photosensitive imaging device to charge a surface of the device with charge originating within a photodiode structure on which the surface is formed; and,   preventing lateral movement of charge through the surface with barriers formed in the surface.   
     
     
         11 . A method as in  claim 10 , further comprising:
 forming a charge pattern on the surface by selectively irradiating the surface.   
     
     
         12 . A method as in  claim 11 , wherein forming a charge pattern comprises selectively radiating the surface to selectively discharge the surface with optical radiation. 
     
     
         13 . A method as in  claim 12 , further comprising:
 applying charged printing agent to the selectively discharged surface to form a print agent pattern on the surface; and,   transferring the print agent pattern to print media to print the print agent pattern.   
     
     
         14 . A printing apparatus comprising:
 a photosensitive imaging surface provided by an extended photodiode structure;   a charging element to apply an electric field to cause movement of charge towards a face of the photosensitive imaging surface; and,   barriers formed in the extended photodiode structure to prevent lateral movement of charge within the photosensitive imaging surface.   
     
     
         15 . A printing apparatus as in  claim 14 , further comprising:
 a write head, to selectively discharge a portion of the photosensitive imaging surface; and,   a grounded metal layer;   
       wherein the charging element is a non-ionizing charging element and the extended photodiode structure is provided between the charging element and the grounded metal layer to form a grounded plate capacitor.