Patent ID: 7652240

Claim:
An image sensor comprising a plurality of pixels, each pixel comprising: a light sensor element ( 12 ), a sensor voltage across the element varying depending on the light incident on the element ( 12 ); a voltage amplifier ( 16 ) having gain magnitude greater than 1; and a sampling capacitor ( 18 ) charged by the voltage amplifier, wherein the voltage amplifier comprises first ( 40 ) and second ( 38 ) transistors in series, the input to the voltage amplifier being provided to the gate of the first transistor ( 40 ), and the output being defined by the junction between the first and second transistors ( 40 , 38 ), and wherein each pixel further comprises a third transistor ( 49 ), the gate of the third transistor being connected to one terminal of the light sensor element ( 12 ), and the source of the third transistor ( 49 ) being connected to the gate of the first transistor ( 40 ).