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Scientific CMOS image sensor
The latest development in imaging technology, scientific CMOS sensors simultaneously deliver high sensitivity, fast readout speeds, and low noise without the addition of multiplicative noise associated with EM-CCDs. The combination of high sensitivity and low noise ensures high signal-to-noise ratio during low-light imaging.
These image sensors have pixels composed of a photodiode and an amplifier that converts charge into voltage. The voltage of each pixel is output by turning on the switch one by one, and the data of each horizontal line is read by the on-chip column amplifier and A/D in parallel and simultaneously. This results in very fast readout speed while keeping the readout noise very low. For more info, see the ORCA-Flash2.8 Technical note  . |
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Interline transfer CCD image sensor (ER-150)
An interline transfer CCD has vertically paired columns consisting of imaging photodiodes and a shielded vertical charge transfer register. Because each pixel is divided into a photosensitive area and a shielded section, the photosensitive area is limited. However, the ER-150 interline transfer CCD used in some Hamamatsu cameras has the added advantage of on-chip lenses, which allow the collection of more photons. This drives the sensitivity higher, up to 70% quantum efficiency for some wavelengths.
The advantage of an interline transfer CCD over other types of CCDs is that the signal accumulation (exposure) and readout can be done simultaneously. Also, image smearing is not an issue in this type of CCD. For more info, see the ORCA-R2 technical note. |
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Electron multiplier CCD image sensor
An electron multiplier (EM) CCD has a similar structure to a frame transfer CCD, but with a special multiplication register between the horizontal register and the output amplifier. The EMCCD has two separate but equal regions, one with pixels exposed to the incoming photons and another equal region (storage area) that is entirely masked to eliminate photons from being detected. The signal in the detection area is transferred to the storage area and then multiplied in the multiplication register through a process called impact ionization.
The advantage of an EMCCD is that signal charges in the CCD are multiplied in the multiplication register. This raises ultra-low signals to levels above the camera’s noise so the signal can be detected. For more info, see the ImagEM technical note. |
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