Blu ray disc
In optical storage devices, the data is read by a laser light. In a standard DVD or CD, the machines used to read the grooves on the CD is a red laser. A blu-ray disc on the other hand uses blue laser light and thus, the name blu-ray disc.
Red light has a wavelength of 650 nanometers while blue light has a more shorter wavelength of about 470 nanometers. The blue laser light allows blu-ray discs to possess much smaller data grooves since the blue light spectrum can be focused on a more concentrated area. Blu-ray technology produces a 405 nanometer blue laser compared to a 650 nm red laser that DVD uses.
Since the pits on the blu-ray is much smaller, it allows higher storage capacities given the same amount of surface area. All that extra data space now allows for a lesser need to compress the data. As a result, higher quality picture or sound can be rendered.
Blu-ray discs has a capacity of 25 Gigabytes on a single layer and 50 GB on a double layer. It is capable of displaying 1080p. The data is written on top of the disc which makes it vulnerable to scratches however, a scratch protection hard coat technology called durabis was later implemented for reduced cost than to house the disc on a cartridge.
Sony corp. ( NYSE: SNE / TYO: 6758) Japan
TDK corp. (TYO: 6762) Japan
Panasonic corp. (TYO: 6752 / NYSE: PC) Japan
Anwell Technologies LTD (SGX: G5X) Hong Kong
Singulus Technologies AG (FWB: SNG) Germany