SOLID-STATE IMAGING DEVICE AND DRIVE CONTROL METHOD FOR THE SAME

摘要

A CMOS sensor has unit pixels each structured by a light receiving element and three transistors, to prevent against the phenomenon of saturation shading and the reduction of dynamic range. The transition time (fall time), in switching off the voltage on a drain line shared in all pixels, is given longer than the transition time in turning of any of the reset line and the transfer line. For this reason, the transistor constituting a DRN drive buffer is made proper in its W/L ratio. Meanwhile, a control resistance or current source is inserted on a line to the GND, to make proper the operation current during driving. This reduces saturation shading amount. By making a reset transistor in a depression type, the leak current to a floating diffusion is suppressed to broaden the dynamic range.

主权项

1. An imaging device comprising:
a plurality of pixels; and a driving circuit configured to drive the plurality of pixels, wherein at least one of the plurality of pixels includes:
a photodiode;a floating diffusion;a transfer transistor connected between the photodiode and the floating diffusion;a reset transistor connected between the floating diffusion and a drain line; andan amplifier transistor, a gate of the amplifier transistor connected to the floating diffusion, wherein the driving circuit includes a transistor connected to the drain line, and wherein a W/L ratio (W is a gate width, L is a gate length) of the transistor connected to the drain line is in a range of 1/0.6 to 1/20.