Blu-ray is a new optical disc standard based on the use of a blue laser rather than the red laser of DVD players. The standard was developed collaboratively by Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and Thomson. Toshiba and NEC are among the companies promoting a competitive optical format, HD-DVD.
The blue laser has a 405 nanometer (nm) wavelength that can focus more tightly than the red lasers used for writable DVD. As a consequence, a Blu-ray disc can store much more data in the same 12 centimeter space. Like the rewritable DVD formats, Blu-ray uses phase change technology to enable repeated writing to the disc.
Blu-ray's storage capacity is enough to store a continuous backup copy of most people's hard drives on a single disc. The first products have a 27 gigabyte (GB) single-sided capacity, 50 GB on dual-layer discs. Data streams at 36 megabytes per second (Mbps), fast enough for high quality video recording. Single-sided Blu-ray discs can store up to 13 hours of standard video data, compared to single-sided DVD's 133 minutes. People are referring to Blu-ray as the next generation DVD, although according to Chris Buma, a spokesman from Philips (quoted in New Scientist) "Except for the size of the disc, everything is different."
Blu-ray discs will not play on current CD and DVD players, because they lack the blue-violet laser required to read them. If the appropriate lasers are included, however, Blu-ray players can play the other two formats.
Blu-ray disc players (BDPs) are available from a number of manufacturers, including Panasonic, Pioneer, Samsung and Sony. Sony's Playstation 3 also has a Blu-ray drive installed.