Blu-ray Disc (official abbreviation BD) is an optical disc storage medium designed to supersede the DVD format. The disc diameter is 120 mm and disc thickness 1.2 mm plastic optical disc, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB (23.31 GiB) per layer, with dual layer discs (50 GB) being the norm for feature-length video discs. Triple layer discs (100 GB) and quadruple layers (128 GB) are available for BD-XL Blu-ray re-writer drives. Currently movie production companies have not utilized the triple or quadruple layer discs; most consumer owned Blu-ray players will not be able to read the additional layers, while newer Blu-ray players may require a firmware update to play the triple and quadruple sized discs.
The first Blu-ray Disc prototypes were unveiled in October 2000, and the first prototype player was released in April 2003 in Japan. Afterwards, it continued to be developed until its official release in June 2006.
The name Blu-ray Disc refers to the blue laser used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs.
Blu-ray Disc was developed by the Blu-ray Disc Association, a group representing makers of consumer electronics, computer hardware, and motion pictures. As of June 2011, more than 2,500 Blu-ray Disc titles were available in Australia and the United Kingdom, with 3,500 in the United States and Canada. In Japan, as of July 2010, more than 3,300 titles have been released.
During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. Toshiba, the main company that supported HD DVD, conceded in February 2008, releasing their own Blu-ray Disc player in late 2009.
The information density of the DVD format was limited by the wavelength of the laser diodes used. Following protracted development, blue laser diodes operating around 400 nanometers became available on a production basis. Sony started two projects in collaboration with Philips applying the new diodes: UDO (Ultra Density Optical), and DVR Blue (together with Pioneer), a format of rewritable discs that would eventually become Blu-ray Disc (more specifically, BD-RE). The core technologies of the formats are similar.
The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000 by Sony. A trademark for the "Blue Disc" logo was filed February 9, 2001. On February 19, 2002, the project was officially announced as Blu-ray Disc, and Blu-ray Disc Founders was founded by the nine initial members.
The first consumer device arrived in stores on April 10, 2003: the Sony BDZ-S77, a US$3,800 BD-RE recorder that was made available only in Japan. But there was no standard for prerecorded video, and no movies were released for this player.
Hollywood studios insisted that players be equipped with Digital Rights Management before they would release movies for the new format, and they wanted a new DRM system that would be more secure than the failed Content Scramble System (CSS) used on DVDs.
The Blu-ray Disc physical specifications were completed in 2004.
In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray Discs. Cartridges, originally used for scratch protection, were no longer necessary and were scrapped.
The BD-ROM specifications were finalized in early 2006.
AACS LA, a consortium founded in 2004, had been developing the DRM platform that could be used to securely distribute movies to consumers. However, the final AACS standard was delayed, and then delayed again when an important member of the Blu-ray Disc group voiced concerns. At the request of the initial hardware manufacturers, including Toshiba, Pioneer, and Samsung, an interim standard was published that did not include some features, such as managed copy.