Blu-ray is a new optical data disc format agreed upon by a consortium of electronics manufacturers including, Hitachi, LG, Matsushita, Pioneer, Philips, Samsung, Sharp, Sony and Thomson.
Like Digital Versatile Discs (DVD) the new format will allow the recording and playback of video and audio and the storage and retrieval of data.
Blu-ray utilises a blue-violet laser (405nm) to write and read data, which has a much shorter wavelength than the red laser (780nm for CD, 635/650nm for DVD) currently used for optical storage, coupled with a much smaller lens aperture (0.85NA) it allows for a highly increased data density which means that more data can be stored on a CD/DVD sized (12cm) disc. Whereas a DVD can store 15GB on a double-layer double-sided disc, a Blu-ray disc can store upto 27GB on a single layer. This means that it could be used to store upto 2 hours of high definition video or 13 hours of standard broadcast quality television.
The Blu-ray consortium has built backwards-compatibility with the current DVD format into the specifications for Blu-ray, hoping that in this way they will avoid alienating DVD enthusiasts and manufacturers.
The first Blu-ray compatible systems are likely to be on-sale in the second half of 2003.
Blu-ray press release February 2002