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The original CMOS and CCDs were developed in the late '60s to early '70s. At that time CCD technology was dominant for many imaging applications because it had better image integrity, image quality and generally better performance than CMOS.
In the '90s, however, there were technological developments and improved fabrication techniques with CMOS fuelled by the rise of mobile phones and video cameras. Andor saw the opportunity to take advantage of this and make CMOS a valid technology for scientific usage.
Andor, the German camera company PCO and a U.S. company, Fairchild Imaging, part of BAE, joined forces and developed the first Scientific CMOS camera or sCMOS.
The low noise characteristics of sCMOS were very exciting. Noise is typically 10 times lower than a CCD. There are much faster read-out speeds than a CCD (up to 10 times faster read-out speeds). This has opened up many more application possibilities.
CCDs were dominant across a lot of application areas up until this point. Taking fluorescence microscopy as the example, a common sensor, would have been the Sony ICX285 with a 6.5 μm pixel size. It had a read noise of about 8 or 9 e- at a speed of about 10 MHz pixel read-out, which gave between 10 and 20 frames a second.
However, if you need to read CCDs faster, this impacts the read noise. This is very different for sCMOS. Because of the parallel read-out structure along with the improved pixel architecture, the read noise is reduced while reading out at a fast rate.
This benefit allows the study of dynamic processes, fast-moving processes, or even moderately fast-moving processes taking advantage of the lower read noise than with CCDs. A CCD would have 8 or 10 e- noise. Whereas sCMOS would read out faster, allowing faster frame rates, with noise down to only about 1 or 2 e-, which is significant.
At Andor we continue to develop novel technologies to improve sCMOS performance. Over the years, the sCMOS cameras Andor has developed are the Neo 5.5 in 2010, Zyla in 2012, Zyla 4.2 Plus and iStar sCMOS in 2016, Sona and Marana in 2018, Balor in 2019 and Sona-6 Extreme and ZL41 Cell in 2022. In the table below a small selection of our sCMOS product range is summarised.
We continue to develop this technology so that we have the best scientific cameras on the market. See also the article 'Development of sCMOS Cameras'.
Neo 5.5 | Zyla 5.5 | iStar sCMOS | Sona-6 Extreme | Marana-4.2B-11 | Balor | ZL41 Cell 4.2 | |
Max QE | 60% | 64% | 95% | 95% | 61% | 82% | |
Max Dynamic Range | 30,000:1 | 33,000:1 | 26,250:1 | 53,000:1 | 33,000:1 | ||
Read Noise | 1 e- | 0.9 e- at 200MHz | 2.4 e- | 1.0 e- | 1.6 e- | 2.0 e- | 0.9 e- |
Array Size | 5.5 MPixel | 5.5 MPixel | 5.5 MPixel | 4.2 MPixel | 4.2 MPixel | 16.9 MPixel | 4.2 MPixel |
Type - front or back illuminated | Front | Front | Front | Back | Back | Large Front | Front |
Date: December 2022
Author: Dr. Jo Walters, Dr. Aleks Marsh, Colin Coates & Alan Mullan
Category: Technical Article