A Charge Coupled Device (CCD) is a photon detector that moves charge along predetermined paths under control of clock pulses. It can collect images in one pixel at a time, by row, or as an entire area. The CCD transfers charge from one potential well to another using electrodes and clock signals. It then reads each pixel's charge level to generate a digital image. CCDs have advantages like sensitivity and cost but also disadvantages like demagnification and potential lower image quality. They are used in applications like astronomy, infrared imaging, and digital photography.

1. Charged Coupled Device

2. Contents
 Introduction
 Readout Process
 Image Scanning
 Image Generation
 Final Procedure
 Aspects of CCD Behavior
 Advantages
 Disadvantages
 Applications

3. Introduction
• A Charge Coupled Device (CCD) is a highly sensitive
photon detector.
• CCDs are dynamic devices that move charge along a
predetermined paths under control of clock pulses.

5. How CCD is clocked out?

6. • The upper section shows charge being collected under one of
the electrodes. To transfer the charge out of the CCD, a new
potential well can be created by holding IØ3 high, the charge
is now shared between IØ2 and IØ3 (section 2).
• If IØ2 is now taken low, the charge will be fully transferred
under electrode IØ3 (section 3).
• To continue clocking out the CCD, taking IØ1 high and then
taking IØ3 low will ensure that the charge cloud now drifts
across under the IØ1 electrodes.
• As this process is continued, the charge cloud will progress
either down the column, or across the row, depending upon
the orientation of the electrodes.

7. Image Scanning
CCDs can be used to collect an image in one of
three ways, either one pixel at a time, one row at
a time, or as an entire area at once.

8. Image Generation

9. Final Procedure
• The final process on the CCD is the reading of each
pixel so that the size of the associated charge cloud
can be measured.
• The CCD is an analogue device, and the analogue
voltage values are converted into a digital form by
the camera electronics.

10. Aspects of CCD Behavior
1. Quantum Efficiency
2. Wavelength Range
3. Dynamic Range
4. Linearity
5. Noise
6. Power

11. Advantages
• Relative simple
• More sensitive than photographic film
• Cheaper to replace if failure
• Modularity-easy upgrades
• Detector costs simple
• No chemical processing is needed

12. Disadvantages
• Demagnification is a major issue
• Vary with application
• Very expensive
• Relates to potentially lower DQE

13. Applications
• Astronomical Imaging
• Infrared Detection and imaging
• Signal Processing
• Digital Photography
• Medical Fluoroscopy

15. CCD Chip

16. References
 http://www.mssl.ucl.ac.uk/www_detector/ccdgroup/optheor
y/ccdoperation.html
 http://www.microscopyu.com/articles/digitalimaging/ccdintro
.html
 http://micro.magnet.fsu.edu/primer/digitalimaging/concepts/
threephase.html
 http://www.sciencedirect.com/science/article/pii/002627147
6906065
 https://www.noao.edu/meetings/gdw/files/Howell_CCDs.pdf
 http://www.science20.com/mei/blog/charge_coupled_device
_ccd

17. Thank you