CDDVDBluRay DVDCDBluRay are all optical data storage devices

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

The Discs • Data stored in the series of lands and bumps on disc • Tracks spiral outward from center • 1. 2 mm thick, maximum radius of 12 cm

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

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

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

$Bibliography Braat, Joseph, P. Dirksen, and Augustus Janssen. Diffractive read-out of optical discs. 2007.$

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. 2 nd 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_files/text_files/beethoven 9. html