Cameraphones - Sensors
Skip contentInstead of capturing a photograph on film, as in earlier cameras, a cameraphone records the picture using a sensor, a light-sensitive integrated circuit. The sensor in a cameraphone is likely to be one of two main types, and these are known by the technology they use: either a CCD (charge-coupled device), which uses an array of capacitors, or a CMOS (complementary metal-oxide-semiconductor) device, which uses transistors. However, for all practical purposes, it is unlikely that the differences between these types of sensor will be a deciding factor when considering which cameraphone meets a particular user’s requirements.
Whatever the type of sensor fitted, the principle of operation will remain basically the same: the light that passes through the lens falls onto the sensor, which contains many individual light-sensitive cells, and each cell reacts to a particular point of light coming from the scene that is to be photographed. The effect of the incoming light is to cause tiny changes in the individual cells of the sensor, creating a pattern that mirrors the image, and these changes are then converted into electrical signals. The electrical output from the sensor is next put through several stages of processing, so that the image of the photographed scene can be reproduced on the phone’s viewfinder, or it may be stored in the phone’s memory for later use.
