Editing Charge-coupled device (section)

==Basics of operation==
[[File:CCD charge transfer animation.gif|thumb|250px|right|The charge packets (electrons, blue) are collected in ''potential wells'' (yellow) created by applying positive voltage at the gate electrodes (G). Applying positive voltage to the gate electrode in the correct sequence transfers the charge packets.]]In a CCD for capturing images, there is a photoactive region (an [[epitaxy|epitaxial]] layer of silicon), and a transmission region made out of a [[shift register]] (the CCD, properly speaking).

An image is projected through a [[lens (optics)|lens]] onto the capacitor array (the photoactive region), causing each capacitor to accumulate an electric charge proportional to the [[light]] intensity at that location. A one-dimensional array, used in line-scan cameras, captures a single slice of the image, whereas a two-dimensional array, used in video and still cameras, captures a two-dimensional picture corresponding to the scene projected onto the focal plane of the sensor. Once the array has been exposed to the image, a control circuit causes each capacitor to transfer its contents to its neighbor (operating as a shift register). The last capacitor in the array dumps its charge into a [[charge amplifier]], which converts the charge into a [[voltage]]. By repeating this process, the controlling circuit converts the entire contents of the array in the semiconductor to a sequence of voltages. In a digital device, these voltages are then sampled, digitized, and usually stored in memory; in an analog device (such as an analog video camera), they are processed into a continuous analog signal (e.g. by feeding the output of the charge amplifier into a low-pass filter), which is then processed and fed out to other circuits for transmission, recording, or other processing.<ref>{{cite journal |author=Gilbert F. Amelio |date=February 1974 |title=Charge-Coupled Devices |journal=[[Scientific American]] |volume=230 |issue=2 |url=http://www.scientificamerican.com/magazine/sa/1974/02-01/ |author-link= Gilbert F. Amelio}}</ref>