Active-pixel sensor

An active-pixel sensor (APS) is an image sensor, which was invented by Peter J.W. Noble in 1968, where each pixel sensor unit cell has a photodetector (typically a pinned photodiode) and one or more active transistors.[1][2] In a metal–oxide–semiconductor (MOS) active-pixel sensor, MOS field-effect transistors (MOSFETs) are used as amplifiers. There are different types of APS, including the early NMOS APS and the now much more common complementary MOS (CMOS) APS, also known as the CMOS sensor. CMOS sensors are used in digital camera technologies such as cell phone cameras, web cameras, most modern digital pocket cameras, most digital single-lens reflex cameras (DSLRs), mirrorless interchangeable-lens cameras (MILCs),[citation needed] and lensless imaging for cells.[3]

CMOS sensors emerged as an alternative to charge-coupled device (CCD) image sensors and eventually outsold them by the mid-2000s.[4]

CMOS image sensor.

The term active pixel sensor is also used to refer to the individual pixel sensor itself, as opposed to the image sensor.[5] In this case, the image sensor is sometimes called an active pixel sensor imager,[6] or active-pixel image sensor.[7]

  1. ^ Cite error: The named reference fossum93 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Fossum2014 was invoked but never defined (see the help page).
  3. ^ Fang, Yuan; Yu, Ningmei; Wang, Runlong; Su, Dong (28 March 2017). "An on-chip instrument for white blood cells classification based on a lens-less shadow imaging technique". PLOS ONE. 12 (3): e0174580. Bibcode:2017PLoSO..1274580F. doi:10.1371/journal.pone.0174580. PMC 5370127. PMID 28350891.
  4. ^ Fossum, Eric R. (1993). "Active Pixel Sensors vs Charge-Coupled Devices" (PDF). Imaging Systems Section, Jet Populsion Laboratory, California Institute of Technology.
  5. ^ US 5631704, Dickinson, Alexander G.; Eid, El-Sayed I. & Inglis, David A., "Active pixel sensor and imaging system having differential mode", published 1997-05-20, assigned to Lucent Technologies Inc. 
  6. ^ Zimmermann, Horst (2000). Integrated Silicon Optoelectronics. Springer. ISBN 978-3-540-66662-2.[page needed]
  7. ^ US 6133563, Clark, Lawrence T.; Beiley, Mark A. & Hoffman, Eric J., "Sensor cell having a soft saturation circuit", published 2000-10-17, assigned to Intel Corp.