CCD sensor at a Glance
At first, the CCD is one of the circuit elements on a computer memory. However, after research done by George Smith and Willard Boyle from Bell Laboratories in 1969, proved that the CCD also has potential applications in signal processing and imaging. Ability CCD as image sensor basically is possible because the material in the form of silicon substrate, one of the semiconductor material, is very sensitive to light. CCD sensitivity reach between the wavelength region 200 - 1100 nm.
This sensitivity is close to the wavelength spectrum of ultraviolet light (UV) and infra-red (IR). With a sensitivity range, the CCD can detect an object that reflects light with a spectrum of UV wavelengths close to the IR. However, CCD high sensitivity achieved in the range of visible wavelength region (visible light) to a wavelength of near infra-red (NIR), which is between 400 to 1100 nm.
Basically, the CCD array consists of a series of light sensitive elements called pixels (picture element). Pixel count varies in number, could reach 10,680 pieces, depending on the type of sensor used. The size of each pixel ranges between 4 to 25 microns. In everyday life, CCD can be found on the fax machine, photocopy machines, document scanners, barcode readers, digital cameras and so on.
Working principle of CCD Array
CCD is an acronym for Charge-Coupled Device, a photon detector instrument with high sensitivity that works with the principle of electric charge capture from the light coming, keep it a while and then turn it into an electrical signal. In general, the principle of CCD are divided into three parts, namely:
- charge collection, changing and storing photons into electrical charge while in smaller areas, called pixels.
- charge transfer, transfer cargo between pixels on the silicon substrate.
- charge conversion, changing the load generated into an electrical signal.But because the CCD is the main mode memory elements.
the CCD larger role as a shift register which acts as a charge-producing transducer conversion of photons that arrived at the same time serves as a transfer charge from one pixel to other pixels, so the CCD can be used as a component of the broadcaster in other devices . Meanwhile, the active element used to receive a photodiode or light photo capacitors.