Patent ID: 8436401

Claim:
A photosensor formed in a semiconductor substrate with a plane surface, said photosensor comprising an active region for converting incident radiation into charge carriers of a first and a second charge type, separating said charge carriers of said first charge type from said charge carriers of said second charge type and accumulating charge carriers of at least one charge type, said active region comprising: a transparent insulator layer formed on said semiconductor substrate; at least three radiation-transmissive electrodes, each radiation-transmissive electrode having a contact for applying an electric potential to said at least three radiation-transmissive electrodes; wherein said at least three radiation-transmissive electrodes are arranged above said transparent insulator layer such that a row of said at least three radiation-transmissive electrodes is formed along at least one straight line in said plane surface; at least one radiation-transmissive electrode between the outermost radiation-transmissive electrodes being subjectable to a global potential extremity of a lateral potential distribution; wherein said at least three radiation-transmissive electrodes are subjectable to a voltage potential such that voltages from the global potential extremity to the outermost radiation-transmissive electrodes decrease or increase monotonically; highly doped diffusion wells respectively adjacent to each of the two outermost radiation-transmissive electrodes of said at least three radiation-transmissive electrodes of said row for collecting said charge carriers, said highly doped diffusion wells being presettable to a given reference potential and connected to an electronic charge-detection circuit; wherein said highly doped diffusion wells are connectable to an electric potential exceeding the potential of said at least three radiation-transmissive electrodes to generate a lateral potential distribution at said semiconductor surface in said active region; wherein said lateral potential distribution with a global extremity between said highly doped diffusion wells causes accumulation of said at least one charge type in said highly doped diffusion wells; and wherein said lateral potential distribution is changeable, thereby enabling the alteration of the size of the effective photosensitive area of the pixel.