3D CCD-style imaging sensor with rolling readout

摘要

The presented readout structure provides charge transport based readout of a photosensitive device with a minimum number of transport gates. The structure uses the given charge storage buckets of the photosensitive device, separated by a minimum sized barrier-gate, to transport the charge out of the pixel field. This new readout schema allows for a fast readout speed based on a 2 phase transport chain and increases the pixel's optical fill factor by significantly reducing the transport gate size compared to state-of-the-art pixels using a 3 or 4 phase CCD readout chain. This readout structure can be exploited for standard photo-detecting elements such as e.g. pinned photo-diodes or any enhanced pixel structure that has additional intelligence incorporated as well. Typical applications are 2D- or 3D-imaging. The process used for manufacturing a sensor with such a readout scheme requires preferably charge transport mechanisms like charge-coupled gate devices as well as the possibility of integrating circuitries of high density. The exploitation of such a combination of process-related features results in a new sensor readout technique that allows for optimizing the pixel's dynamic range and optical fill factor.

主权项

1. A photo sensor, comprising:
a two dimensional array of pixels, each of the pixels including a photo sensitive area including a drift field for transporting photo generated charges, and at least two pixel storage gates that alternately receive the photo generated charges from the photo sensitive area to sample at different phases; and readout chains formed from the pixel storage gates for the pixels for lines in the array, the readout chains enabling the photo generated charges to be passed between the pixel storage gate for successive pixels through the lines; and a decoder for controlling the readout chains to transport the photo generated charges generated in each of the pixels out of the array by successively shifting the photo generated charges for each of the pixels through the readout chains and laterally out of the array, wherein the decoder controls the chains to laterally move an increasing number of separate charge packets in a particular shift cycle relative to a prior shift cycle during reading out of the chains.