Weekly Patent Review

The most interesting application of this week is Kodak's US20090021612. It attempts to overcome the new WRGB-colored sensor problem of early signal overflow in panchromatic pixels. The multiple readout curtains are arranged in such a way that panchromatc pixels get shorter exposure time than colored ones. Then, generalizing the idea, Kodak proposes a readout scheme with different exposure times per each color, as on the figure below:



My first concern about this idea is different motion artifacts for different colors, if fast moving objects are photographed or in presence of camera shake. It might require a good deal of image processing to conceal these artifacts. The second concern is a more difficult wiring of the pixel array, which might result in lower fill factor - can be resolved, if made in BSI.

TSMC patent application US20090020838 proposes to use black photoresist rectangles between the neighboring pixels under color filter to reduce crosstalk. I don't think the idea is new, but there might be some new trick in the manufacturing process of the rectangles.