Concepts in Digital Imaging Technology Interactive Tutorials

• Avalanche Diodes

  An avalanche photodiode is a silicon-based semiconductor containing a pn junction consisting of a positively doped p region and a negatively doped n region sandwiching an area of neutral charge termed the depletion region.

• Electron-Bombarded CCDs

  Electron-bombarded charge-coupled devices (CCDs) are a relatively new development in which photons are detected by a photocathode in a manner similar to an image intensifier.

• Binning

  Discover how clock signals controlling a CCD can be used to combine integrated charge from adjacent pixels to improve signal-to-noise ratios and increase the readout frame rate.

• CCD Blooming

  Under conditions where a CCD is exposed to very high intensity illumination, it is possible to exhaust the storage capacity of the CCD wells, a condition known as blooming.

  
  

• CCD Clocking Schemes

  Charge transfer through CCD shift registers occurs after integration to relocate accumulated charge information to the sense amplifier, which is physically separated from the parallel pixel array.

• Building A Charge-Coupled Device

  Explore the steps utilized in the construction of a charge-coupled device (CCD) as a portion of an individual pixel gate is fabricated on a silicon wafer simultaneously with thousands or even millions of neighboring elements.

• Building A Charge-Coupled Device (Version 2)

  Like the first version this tutorial examines the fabrication of a CCD as a portion of an individual pixel gate is fabricated on a silicon wafer simultaneously with thousands or even millions of neighboring elements.

• Electronic Shutters

  Electronic shutters are employed in charge-coupled devices (CCDs) to control integration time (exposure) of the photodiode array and reduce smear when capturing moving objects in the microscope.

• CCD Operation

  Explore the operation of a charge-coupled device (CCD) imaging semiconductor with this interactive Flash tutorial. Modern CCDs consist of a light-sensitive sandwich of insulating silicon dioxide positioned beneath an array of photodiodes and above an array of metal electrodes.

• Frame-Transfer CCD Operation

  Designed to operate fast and efficiently without a shutter or synchronized strobe, frame-transfer CCDs exhibit higher frame rates than full-frame designs. Explore image acquisition and transfer in frame-transfer charge-coupled devices with this interactive Java tutorial.

• Interaction of Photons with Silicon

  In a charge-coupled device (CCD) incident light must first pass through a silicon nitride passivation coating as well as several thin films of silicon dioxide and polysilicon gate structures before being absorbed into the silicon substrate.

• Full-Frame CCD Operation

  Full-frame charge-coupled devices have the simplest architecture and are the easiest devices to build and operate. These devices feature high-density pixel arrays capable of producing digital images with the highest resolution currently available.

• Interline CCD Operation

  Interline charge-coupled device architecture is designed to compensate for many of the shortcomings of frame-transfer CCDs.

• Microlens Arrays

  Microlens arrays (also referred to as microlenticular arrays or lenslet arrays) are used to increase the optical fill factor in CCDs, such as interline devices, that suffer from reduced aperture due to metal shielding.

• Photomultiplier Tubes

  Photomultiplier tubes, useful for light detection of very weak signals, are photoemissive devices in which the absorption of a photon results in the emission of an electron.

• Side-On Photomultiplier Tubes

  In the side-on photomultiplier tube design, photons impact an internal photocathode and eject electrons from the front face.

• Channel Photomultipliers

  Channel photomultipliers represent a new design that incorporates a unique detector having a semitransparent photocathode deposited onto the inner surface of the entrance window.

• Proximity-Focused Image Intensifiers

  Image intensifiers were developed for military use to enhance our night vision and are often referred to as wafer tubes or proximity-focused intensifiers.