Standard Article

Imaging Detectors

Charge-coupled Devices and CMOS Active Pixel Sensors

  1. Morley M. Blouke

Published Online: 15 JUL 2005

DOI: 10.1002/3527600434.eap058.pub2

Encyclopedia of Applied Physics

Encyclopedia of Applied Physics

How to Cite

Blouke, M. M. 2005. Imaging Detectors. Encyclopedia of Applied Physics. .

Author Information

  1. Scientific Imaging Technology Inc., Tigard, OR, USA

Publication History

  1. Published Online: 15 JUL 2005


Charge-coupled devices (CCDs) were first introduced in 1970 with the demonstration of an eight-bit linear shift register. The concept of charge coupling was novel in the integrated circuit arena in that information was represented by discrete charge packets, which were manipulated in the device and, only at the output, converted to a voltage that could be measured. By operating in the charge domain, the charge-coupled device is a true integrated circuit; it is impossible to make such a device from a collection of discrete components.

The serious development of Active Pixel Sensors began in the early 1990s, though their heritage hails from work done in the 1960s. Active pixel sensors get their name from the nature of the structure that makes up the pixel: a charge collection site and readout circuitry are provided within each pixel.

This article provides an overview of charge-coupled devices and active pixel sensors, their design, structure, operation, and performance.


  • charge-coupled device;
  • active pixel sensor;
  • visible imager;
  • CCD