5. Image sensor operation

The use of charge-coupled devices as image sensors was one of the driving forces behind their development as a replacement for picture tubes. (bulky components, reputation for fragility, high-voltage power supply and short life expectancy), initially for professional applications, quickly followed by consumer applications.

In fact, silicon's excellent sensitivity to visible light, combined with its predominance as the basic material for modern integrated electronics, has enabled the development of technologies and led to miniaturized designs conducive to very high spatial resolution imagers.

These properties are implemented in a number of devices, whose architectures are based around two types of image point, or pixel (short for picture element), the photodiode and the photoMOS, and will be detailed below.