Learn everything about Blu-ray Media

Blu-Ray is a new generation, high capacity and speed data storage technology. It is supported by several industry leading companies and has a bright future according to professionals.

The name Blu-ray Disc (BD) is derived from the blue-violet laser it uses to read and write to the disc. A Blu-ray Disc can store substantially more data than the common DVD format, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser and CDs use an infrared 780 nm laser), which allows more information to be stored digitally in the same amount of space. In comparison to HD DVD, which also uses a blue laser, Blu-ray Disc has more information capacity per layer (currently 25GB, but test media is up to 200GB). Sony has released 50GB recordable BDs and will soon be releasing 50GB BD media discs. In August 2006, TDK developed a Blu-ray Disc with a 200GB capacity.

The Blu-ray Disc is a very similar format to PDD, another optical disc format developed by Sony (which has been available since 2004) but offering higher data transfer speeds. PDD is not intended for home video use and is aimed at business data archiving and backup. The UDO format is also aimed for similar purposes.

While current optical disc technologies such as DVD, DVD±R, DVD±RW, and DVD-RAM rely on a red laser to read and write data, the new format uses a blue-violet laser instead, hence the name Blu-ray. Despite the different type of lasers used, Blu-ray products can easily be made backwards compatible with CDs and DVDs through the use of a BD/DVD/CD compatible optical pickup unit. The benefit of using a blue-violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser spot with even greater precision. This allows data to be packed more tightly and stored in less space, so it's possible to fit more data on the disc even though it's the same size as a CD/DVD. This together with the change of numerical aperture to 0.85 is what enables Blu-ray Discs to hold 25GB/50GB.

- About 9 hours of high-definition (HD) video can be stored on a 50GB disc.
- About 23 hours of standard-definition (SD) video can be stored on a 50GB disc.

A single sided Blu-ray disc has the storage capacity of 25GB. A dual layer Blu-ray disc has the storage capacity of 50GB. Blu-ray technology has the possibility of reaching 200GB on a single disc.

TDK recently announced that they have created a working experimental Blu-ray Disc capable of holding 200 GB of data on a single side (six 33 GB data layers).

The Blu-ray Disc Association specified that formats for end-users are BD-ROM, BD-R and BD-RE.

BD-ROM format will be used for read-only medias, like videos, games or et cetera.
BD-R format will allow users to write data on disc for one time and store.
And the BD-RE format will have ability to be written on it several times.

The Blu-ray Disc Association approved there specifications on January 2, 2006. Licensing of the BD-R and BD-RE 2.0 specifications began December 26, 2005. Specifications have been approved for the Blu-ray disc single and dual layer specifications.