Solid-state imaging device

Abstract

A photoelectric conversion device suitable for use as an element of a photodetector array includes a photodiode for generating a first signal charge in response to incident light, an output unit including a JFET, and at least one transistor having an electrode that generates a second signal charge in response to incident light. The first and second signal charges may be output separately or combined. The second signal charge, or the first and second signal charges combined, may be monitored during an exposure time to determine the desired end of the exposure. An image sensor array may have one or more pixels with such light monitoring capability. The output signal for monitoring the light may be output over a reset drain interconnection, directly from the monitoring pixel or through other pixels via inter-pixel MOSFETS. Exposure time may be controlled, by timing a shutter or a strobe or the like, based on the monitored accumulation of signal charge during exposure. Microlenses may be provided on-chip to increase the effective aperture ratio of the array. The microlenses are designed to avoid interfering with the incident light used for monitoring. Resulting pixel-to-pixel variations in effective aperture ratio, if any, may be electronically compensated.