CD/DVD/Blu-Ray

1
CD/DVD/Blu-Ray
DVD/CD/Blu-Ray are all optical data storage
devices. All three employ lasers and the
principle of point-by-point scanning of an object
to extract the recorded information on the disc.
They differ in their capacity to store data and
by the type of laser light required to decode
that data.

• Travis Harrall, Zac Spencer Trevor Green

2
The Discs

• Data stored in the series of lands and bumps on
  disc
• Tracks spiral outward from center
• 1.2mm thick, maximum radius of 12cm

3
The Player

• Disc drive motor
• Lens/Laser system
• Tracking drive

4
How are they different?
CD DVD Blu-Ray
Storage Capacity .65 GB per layer 4.7 GB per layer 23 GB per layer
Numeric Aperture .45 .60 .85
Wavelength of Laser 780 nm (infrared) 650 nm (red) 405 nm (purple)
Track Pitch 1.6 µm .74 µm .32 µm
Maximum Rotating Speed 500 rpms 1600 rpms 10,000 rpms
Minimum Size of Pits .83 µm .4 µm .14 µm
5
Beam Diameter
CD DVD Blu-Ray
Storage Capacity .65 GB per layer 4.7 GB per layer 23 GB per layer
Numeric Aperture .45 .60 .85
Wavelength of Laser 780 nm (infrared) 650 nm (red) 405 nm (purple)
Track Pitch 1.6 µm .74 µm .32 µm
Maximum Rotating Speed 500 rpms 1600 rpms 10,000 rpms
Minimum Size of Pits .83 µm .4 µm .14 µm
6
Bibliography

• Braat, Joseph, P. Dirksen, and Augustus Janssen.
  Diffractive read-out of optical discs. 2007.
  1-11. Web. 19 Nov. 2010.
• Kuhn, Kelin J. Laser Engineering. N.p. Prentice
  Hall, 1998. Print.
• Pohlmann, Ken C. The Compact Disc Handbook. 2nd
  ed. Vol. 5. Madison A-R Editions, Inc, 1992.
  51-53. Web. 19 Nov. 2010.
• van de Nes, A S, J J M Braat, and S F Pereira.
  "High-density optical data storage." Reports of
  Progress in Physics 69 (2006) 2325-61. Web. 19
  Nov. 2010.
• http//www.explainthatstuff.com/cdplayers.html
• http//electronics.howstuffworks.com/dvd.htm
• http//www.blu-ray.com/faq/
• http//electronics.howstuffworks.com/blu-ray.htm
• http//electronics.howstuffworks.com/cd.htm
• http//www.yeodoug.com/resources/handbook/image_fi
  les/text_files/beethoven9.html