CMOS and charge-coupled device are imaging sensors. Non-amplifying types of junction photosensors include photodiodes, solar cells, CMOS and charge-coupled devices. Amplifying-type junction photosensors include phototransistors, photothyristors and photo-field-effect transistors (FETs). Junction-type photosensors are further amplifying and non-amplifying type. These are also known by the name of photoresistors, light-dependent resistors and photocells. Photoconductors are bulk semiconductor devices whose resistance decreases with increase in incident light intensity. Photoconductors and junction-type photosensors use internal photo effect. Common photo-emissive sensors include non-imaging sensors such as vacuum photo cells and photomultiplier tubes, and imaging sensors such as image intensifier tubes. Photo-emissive sensors are based on external photo effect. Photoelectric sensors are further of two types: Devices that depend on the external photo effect for their operation and devices that make use of some kind of internal photo effect. Photosensors are classified into two major categories: Photoelectric and thermal. While individual photosensors such as PIN photodiodes and avalanche photodiodes find applications in military optronic systems including laser rangefinders and target designators, Lidar sensors and navigation sensors, sensor arrays such as complementary metal-oxide semiconductor (CMOS), charge-coupled device and avalanche photodiodes are at the core of imaging sensor systems including Ladar sensors, night vision devices, laser and imaging infrared seekers. Optronic sensors constitute the heart of a variety of systems ranging from simple gadgets like light meters to the most complex of military systems like precision-guided munitions, laser rangefinders, target trackers, remote sensing systems, navigation sensors, sniper and explosive detectors, fibre-optic and laser-based communication systems, night vision devices, Lidar and spectroscopic sensors.
#Dark noise equivalent power cmos series#
Hence this six-part article series starts with an overview of these sensors. Understanding optronic sensors and related sensor systems is essential to understanding the design and operation of a large number of defence systems.