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Leak! Canon developing multi-layer CCD
This news leaked to me last night, I've just verified it with another industry source. Canon, in association with an undisclosed partner are developing a totally new class of CCD which will revolutionize digital cameras. Their so called multi-layer CCD uses the properties of a specially developed glass membrane which spreads the light equally to each layer.
Canon's multi-layer CCD
Unlike traditional CCD's which have image sensors coated with a coloured dye in the "bayer pattern" the new multi-layer CCD has a grid like clear glass top (coated with a special IR filter) which then distributes the light equally to each of the three colour sensors embeded below. The side view shown on the right is a slice through one pixel with the light entering from the top, the height of this sensor is much exagerrated for clarity. Each pixel "cell" layered to the next by a superfine reflective coating to prevent leakage of photons between pixels (also known as smear).
The new CCD is said to be initially be developed with a 3.3 megapixel resolution (2048 x 1536), however, due to it's multi-layered nature it will in fact have an amazing 9.9 million individual colour sensors. Manufacturered using a 0.5 micron process the CCD will be 2/3" diagonally and has a low dark current of just 400 picoamperes/centimeter2. Due to it's unique multi-layered nature it's the first CCD ever to produce a full 36-bits per pixel (12-bits per colour) of information. It's unlikely this CCD will make it into the current generation of EOS-D Digital SLR's but perhaps next year...
Increasing the dimensions of the CCD removes some of the recent problems encountered in manufacturing lenses of sufficient quality to produce a focused, high resolution image on the CCD's surface.
Sensitvity of the new device seems to be the only problem, my source quoted a basic sensitivity of just ISO 80, although this is expected to improve in the final product.
This amazing bit of news should herald a new era in image quality for digital cameras. Always the bug-bear of image quality the traditional Bayer pattern seems to have finally met its end.