Future of CMOS sensors. Sony back-illuminated sensors

[PortableAstronomer]

As many of you know, CCDs are typically the favoured choice for astro imaging (over CMOS sensors). It is a shame that a few years ago Sony appeared to dump their excellent CCD manufacturing after the ICX285 ( Atik 314L, SXV-H9 etc..) and went CMOS bandwagon, leaving the more noisy Kodak sensors as the only realistic large-format mono CCDs.

Many of you also know that the fill factor of CCDs is better than CMOS sensors, most of the CCD surface is light-sensitive, where CMOS sensors have more micro electronics on the surface of the pixels, reducing light-collecting area.

DSLR cameras get around this by using microlensing, so CMOS has caught up in recent years. ( and yes I know, the Nikon D40/D70/D100 cameras used real Sony super HAD CCDs, before they also switched to CMOS)

But now I'm reading this article about the Sony Exmor R back-illuminated CMOS sensors,

Sony unveils 'Exmor R' back-illuminated CMOS technology: Digital Photography Review

it suggested to me that the back-illumination of the sensor (which puts all the electronics behind the sensitive area) would in theory get rid of all the downsides of CMOS, which is still an ugly word in Astro Imaging.

These examples from Sony are intended for video cameras, so won't be particularly large, but you never know, could a future large-format mono development of this be as good as the much loved ICX285 CCD, only bigger?

Discuss...? :-)

[riklaunim]

ICX285 was replaced by ICX674 and partially by ICX625/655 which will be probably in one of Atik Hyperstar cameras. Exmor CMOS sensors are already announced in machine vision cameras like Point Grey or GigE QHY (not the astro cams section).

Here is Point Grey QE test: http://www.ptgrey.com/support/downloads/documents/Point_Grey_Sensor_QE_Comparison_FAQ.pdf

IMX035 is the Exmor CMOS and in terms of QE it is slightly better than ICX285, and ICX674 is better than the CMOS.

[PortableAstronomer]

hmmm, very small pixels in those sensors, and still all of then are 1/3 inch size or smaller.

I was fantasising more about larger format mono possibilities that could come out of this. Something like a contender for the KAF-8300 or 4022, but with lower noise and progressive scan.

[riklaunim]

ICX674/625 is 2/3" - the same size as ICX285 Sony doesn't make bigger mono CCDs for some reason.

[michael.h.f.wilkinson]

Really interesting development. These back-illuminated CMOS chips could be real killers!