A 4M-PIXEL CMD IMAGE SENSOR WITH BLOCK AND SKIP ACCESS CAPABILITY

A 4M-pixel Charge Modulation Device (CMD) image sensor with pixel size of 7.5 x 7.5 mu m(2) has been developed for high-resolution imaging a nd machine vision applications. This CMD image sensor features three s canning modes and low dark current generation. The three scanning mode s include a full readout mode, a block access mode, and a skip access mode. A 4M-pixel resolution image is obtained in a single readout cycl e with the full readout mode, while an arbitrary window-of-interest ca n be read out with the black access mode. The skip access mode reads e very fourth pixel in both horizontal and vertical directions, The bloc k and skip access modes allow real-time monitoring of a partial and ro ugh image of the full angle of view. These scanning modes are realized by using dynamic shift registers. The sensor also has a capability of lowering the dark current generation during a long integration time b y controlling the drain voltage of the CMD. The sensor has the sensiti vity of 440 nA/lx and consumes 90 mW at the horizontal scanning freque ncy of 12 MHz in the block access mode. Measured dynamic range of 70 d B is limited by the dark current shot noise in the full readout mode.