What is a Blu-ray disc?

A Blu-Ray disc, also know as a BD Disc, is the next generation of recordable optical storage media used for displaying High Definition Video, 7.1 theater surround sound, and up to 50GB of storage capacity. The dimensions of a Blu-Ray disc are the same as a traditional CD or DVD: 12cm in diameter and 1.2mm in thickness. However, the speed, capacity, and versatility of Blu-ray far surpasses that of it’s predecessors.

The massive storage capacity of a Blu-ray Disc is possible because it utilizes a track pitch of just 0.32 microns. This is less than half the track pitch of a DVD and the diameter of the laser spot is approximately 80 percent smaller. Blu-Ray burners use a combination of a blue laser, which has a short 405nm wavelength, and an advanced object lens with a large 0.85 numerical aperture to utilize Blu-ray Disc's high density storage capacities.

How do I choose a recordable Blu-Ray Disc?

The Blu-Ray format currently has several options for recordable blank BD discs. Blu Ray discs vary by their re-write capabilities and the number of recording layers contained within the disc.

The current Blu-Ray disc options are as follows:

BD-R – This format has a single layer storage capacity of 25GB which can hold approximately 3.5hrs of 1920 x 1080 resolution high definition video. Although a BD-R Blu-Ray disc can be read many times, it can only be recorded to (burned) once.
BD-RE – This format has all of the same specifications as the BD-R format, however is has the added capability of being erased and re-burned many times. The number of times a BD-RE disc can be re-recorded depends on the quality of manufacturing. TDK claims that their BD-RE discs can be re-written up to 10,000 times.
BD-R DL – This format has a double layer capacity of 50GB. It can hold approximately 7hrs of high definition video, and can only be burned once.
BD-RE DL – This format has the benefit of having both the double layer capacity of 50GB as well as the re-writing capability of the BD-RE disc.

Other options for recordable Blu-Ray Discs include recording speed (2x, 4x, 6x) and printable surfaces options. Some Blu-Ray Disc manufactures currently offer discs with white inkjet, white Everest, and silver thermal printable surfaces.

TDK Corp. is currently developing quad-layer BD-R discs with a 100GB capacity and 6x burning speed.