charge coupled device -Principle,working,construction.
- 1. TOPIC: Charge couple devices (CCD) PHYSICS Presented by : • Raghuram G • Ravishankar A.G • Parameshwaran P 1
- 3. PRESENTATION OUTLINE :- 3 1.What is CCD ? 2.How does CCD work ? 3.Where is CCD used?
- 4. Charge couple device (CCD) Physicists George Smith and Willard Boyle invented the CCD .
- 5. 5 Charge couple device (CCD) PRINCIPLE : CCD is the acronym for “Charge coupled device”. It is an integrated circuit which consists of light sensitive elements and it captures and stores the image in the form of electrical charge. It is based on Metal Oxide Semiconductor. Example- SiO2, ZnO, Fe2O3, TiO2. The principle of Charge couple devices is Photoelectric Effect. When light (photons) strikes the photosensitive surface of the CCD, it generates electron-hole pairs. The number of electrons produced is directly proportional to the intensity of the light.
- 6. 6 ARCHITECTURE OF CCD : 1.Full-Frame CCD: • The entire sensor captures light (no blocked areas). • Needs a mechanical shutter to control exposure. • Very clear images but slower to capture.
- 7. 7 • Splits the sensor into two parts: one for capturing light, another for storing images. • Faster than full-frame because it doesn’t need a shutter. 2.Frame-Transfer CCD :
- 8. 8 • It has tiny storage areas next to each light- capturing pixel. • It moves data quickly to storage, making it fast and good for video. • It is slightly less sensitive to light compared to full-frame. 3.Interline Transfer CCD :
- 9. STRUCTURE OF CCD : 9 Series of MOS capacitors
- 10. Single Metal Oxide Semiconductor Capacitor CCD-STRUCTURE 10
- 11. CCD - CHIP 11 Based on the intensity of light ,charge is accumulated in the pixel
- 12. WORKING OF CCD 12 1.When light photons hit the CCD, they interact with the semiconductor material, releasing energy. 2.This energy excites electrons, creating electron-hole pairs. The number of pairs depends on the light intensity. 3.Each pixel in the CCD has an electric field that forms a potential well. Photoelectrons are stored in Potential well.
- 13. READOUT PHASE 13
- 14. 14 • Smaller in size . • Consumes less power and works at low voltage. • Low noise and high sensitivity. • Very faint and bright targets can also be measured. • No chemical processing is needed. Advantages of charge coupled device :-
- 15. 15 Disadvantages of charge coupled device :- • Slower readout. • No direct access to the pixel. • Higher Cost.
- 16. • Used in astronomy for imaging, photometry and spectroscopy. • Used in digital photography. It converts captured light into digital data. • Used in image sensors. • Used in signal processing. • Used in Medical fluoroscopy. Applications of charge coupled device :- 16
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