Blu-ray Disc

Blu-ray disc is an optical disc format for the storage of digital media, including high-definition video. The name Blu-ray is taken from the blue-violet laser used to read and write these type of discs. Blu-ray disc can store data more than the DVD format is more common because the wavelength of a blue-violet laser used only 405 nm where the shorter 650 nm red lasers, used on DVD and CD. A rival Format Blu-ray, HD DVD also use the same type of laser. Blu-ray disc can store 25 GB on each lapisannya compared with 4.7 GB on DVD. Some manufacturers even have made Blu-ray single layer and double layer (50 GB) that can be rewritten.[1] several movie studios support Blu-ray format has been released or even announced it would be releasing movies on discs with capacity of 50 GB blue ray is shorter than the wavelength of the laser makes it possible to store more information on a 12 cm CD/DVD disk size. Minimum "spot size" in which a laser can be focused is limited by diffraction, and depends on the wavelength of the light and the numerical aperture of the lens used to focus it. With a decrease in wavelength, increasing the numerical aperture 0.60 – 0.85 and making the cover a thin layer so the optical effects that are spared from the unwanted, the laser can be focused to a smaller spot. This allows more information to be stored in the same area.

Blu-ray disc similar to the PDD, other optical disc format developed by Sony which have been available since 2004. PDD has a data transfer speed is higher. PDD is more aimed at the use of business data or backup.

Blu-ray now has been involved in a war with the rival HD DVD format developed by Toshiba. After several major retailers and film companies began to end support for the HD DVD format in early 2008, on February 19, 2008, Toshiba announced it would end the production and development of HD DVD so directly settled the format war.