6.1 A 1/1.7-inch 20Mpixel Back-illuminated stacked CMOS image sensor for new imaging applications

The demand for low-noise (for capturing a clear image in low-light conditions), high-speed (for slow-motion applications and reducing rolling shutter distortion) and high-resolution (for formats beyond 4K) CMOS image sensors is still increasing. In addition, the emerging camcorder market typified by handsfree devices requires the simultaneous capture of still and moving images. To improve noise performance, a method of pseudo-multiple sampling has been proposed [1]. However, the noise reduction effect is insufficient due to the non-uniformity of the CDS period. For high frame rates, multichannel and high-data-rate interfaces have been reported [2-4]. For simultaneous capture of still and moving images, a seamless mode change has been shown [5], but it is necessary to convert a still image (full pixel data) to a moving image (2×2 binning data) by an external DSP.