What is Blu-ray?
Blue Laser
Blu-ray discs (BD) get their name from a combination of the words blue and optical ray. The format was developed by the Blu-ray Discs Association (BDA), which is made up of a group of leading consumer electronics, major film studios and PC companies, including our
parent company, Mitsubishi Kagaku Media. Verbatim, as a subsidiary of MKM, has therefore, first hand access to the latest in Blu-ray technology.
The Blu-ray disc’s higher storage capacity is enabled by a blue laser that has a shorter wavelength than the standard red laser used in CD (780nm) and DVD (650nm) technology. Blu-ray disc utilises a blue laser with a wavelength of only 405nm combined with a strong lens system with a numerical aperture of 0.85. This results in a ultra-small laser spot which allows writing smaller data pits which increases the amount of data on the disc. Due to the small data entry spot on the disc surface hard coating is needed on Blu-ray discs.
How a BD Disc Works
Red Laser (DVD) | Blu-ray (BD-R/RE) |
technology | technology |
Data
Polycarbonate Layer 1
Recording Layer
Reflective Layer
Polycarbonate Layer 2
Disc Label
Data
Laser
Hardcoat Layer
Cover Layer
Protective Layer
Recording Layer
Protective Layer
Reflective Layer
Polycarbonate Layer
Disc Label
Minimum pit length = 0.4μm Track pitch = 0.74μm Capacity = 4.7GB | Minimum pit length = 0.15μm Track pitch = 0.32μm Capacity = 25GB |
