A charged coupled device (CCD) is basically a device that allows the transportation of electrically-charged analog signals through different capacitors set up in a successive series. The device is controlled by a clock signal that oscillates between high and low states. The entire system acts as a shift register that has its inputs and outputs linked together in series. This allows a charged coupled device to be used as a way of delaying analog signals.

The most common use of these devices is for photoelectric light sensors that are linked to parallel analog signals. This technology is the basis of how a digital camera, video recorder or picture phone operates.

In 1961, a researcher at the Jet Propulsion Laboratory named Eugene F. Lally wrote a paper called “Mosaic Guidance for Interplanetary Travel.” He explored the idea of using a series of optical detectors that implemented digital processing to create a photograph. Although this theory was sound, it wasn't until 1969 when two scientists working at AT&T Bell Labs, Willard Boyle and George E. Smith, developed a charged coupled device for use as a memory technology. Using this technology, other companies developed ways to capture the photoelectric effect and make electronic images. In 1974, the first commercial digital photography device was created that was capable of doing 100 pixels.

The way a charged coupled device works in capturing images is by focusing an image that is projected from a lens onto the photoactive capacitor array. This results in each capacitor accumulating an electric charge that is proportional to the light intensity of the image. This captures a two-dimensional image that is transferred to a charge amplifier, which in turn coverts it into voltage. This image is then stored digitally in a memory module and can be accessed at a later time.

While the basic charged coupled device is efficient to capturing luminance, it has a difficulty in rendering color. To bypass this problem, modern digital cameras use a device called a Bayer mask over the CCD. It links four pixels into blocks and filters different luminance levels as different colors. These pixels are colored with red, blue and two green as the human eye can identify green more readily than other colors.

Another technology under construction in the early 21st century involves high-resolution charged coupled device chips that can use more of the luminance color at different aperture sizes. It accomplishes this by implementing a device called a dichroic beam splitter prism that splits each color into its native component.