CMOS sensor

A CMOS sensor is an electronic chip that converts photons to electrons for digital processing.

CMOS (complementary metal oxide semiconductor) sensors are used to create images in digital cameras, digital video cameras and digital CCTV cameras. CMOS can also be found in astronomical telescopes, scanners and barcode readers. The optical technology is used in machine vision for robots, in optical character recognition (OCR), in the processing of satellite photographs and in the enhancement of RADAR images, especially for meteorology.

Like other semiconductor technologies, CMOS chips are produced by photolithography. The chips feature an array of minute light-capturing cells that pick up the photons at their various wavelengths as focused by a lens, translating them into electrons, much like a tiny solar cell. The CMOS cells are surrounded by transistors, which amplify the charge of the electrons gathered by the cells, sending them across the chip by tiny wires in the chip’s circuitry. A digital-to-analog converter at one corner of the device reads the electrons and translates the differing charges of individual cells into pixels of various colors. 

CMOS’ low manufacturing cost makes it possible to create low-cost consumer devices. Advances in CMOS technology have made it possible for them to approach their competitor in high-end digital cameras, charge-coupled devices (CCD). In contrast to CMOS, CCD cells are not surrounded by transistors and must actively use power to gather light. This makes them less power-efficient but also enables the benefits of a lower-noise image and greater light sensitivity.