Blu-ray – optical disk format for storing videos, audio files and archive data. It uses a 120mm (4.7 inches0 diameter platter and was released in 2006, replaced DVDs. They were used for distributing movies with some archival storage use cases.
The polycarbonate disk is 120m in diameter metres (4.7 in) and 1.2 millimetres (0.047 in) thick, like DVDs. Blu-ray disks are written and read using a 405nm blue laser, and can store up to 50 GB in dual-layer format; 25GB in single layer format.
Distribution of movies by Internet streaming has replaced physical distribution by Blu-ray and the earlier DBD format optical disks. Panasonic produced archival Blu-ray technology.