Image: Comparison CD DVD HDDVD BD

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Description: Comparison of various characteristics of a Compact Disc, and single-layer Digital Versatile Disc, High-Definition/Density Digital Versatile Disc and Blu-ray Disc. Dimensions indicated are track pitch (p), pit width (w) and minimum length (l), and laser spot size (⌀) and wavelength (λ). For comparison with analogue media, the pitch of the spiral of a 240-groove-per-inch long-playing record and a Laserdisc are 106 μm (66 times the CD track pitch) and 4.6 μm (2.9 times), respectively.[1] The tip of a 0.7-mil stylus has a diameter of 18 μm (11 times that of the CD laser spot).

Data is from [2], [3], [4] and [5]. The Airy disk profile is based on [6] with rings darkened by a factor of 5 for clarity.

Note that the wavelength is in vacuum or air; below the surface of the disc, the index of refraction of polycarbonate (n=1.585) means that the wavelength is only 63% of the listed values.
Author: Cmglee
Usage Terms: Creative Commons Attribution-Share Alike 3.0
License: CC-BY-SA-3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0/
Attribution Required?: Yes

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Compact disc

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