Full frame transfer CCD sensor
In case of the full frame transfer sensor, the complete sensor surface is light-active (the fill factor is up to 100 per cent), therefore this sensor type is ideal for maximum brightness sensitivity. It is thus often used in scientific and astronomic applications in order to detect smallest quantities of light over a long time (several minutes, strongly cooled).
This sensor design does not have any vertical shift registers so that the charge of the pixels must be shifted through the neighbouring pixel structures to a horizontal shift register.
Even during the readout the pixels are light-active. In order to avoid smear effects, the sensor must be darkened by means of a mechanic shutter while transferring the image. This in only interesting for low image refresh rates (bulb exposure) and hardly for any industrial applications with many images per second. There it could only be used with a flashing illumination in order to read out the sensor in the dark phase.