BLU RAY DISC ASSOCIATION Developed blu ray disc format
TYPES OF BLU RAY DISC• SINGLE LAYER 25/27 GB•DOUBLE LAYER• 50 GB MULTI LAYER > 50 GB
FORMATS OF BD4 different formats: BD ROM (read only):- for reading recorded content. BD – R (recordable):- for PC data storage. BD – RW (rewritable):- for PC data storage. BD – RE (rewritable):- for HDTV (High Definition Television) recording.
FEATURES OF BLU RAY DISC: Record HDTV without any quality loss. Instantly skip to any spot on disc. Record on one program while watching other on the disc. Create play list.
THE TECHNOLOGY Disc stores digitally encoded data in PITS.
THE TECHNOLOGY• Pits : spiral grooves that run from the centre of the disc to its edges Bumps : other sides of these edges. Track pitch : it is the distance between the two tracks (of pits) on the surface. More pits, less track pitch ----- more storage capacity
THE TECHNOLOGY In blu-ray disc: Pit size – 0.15 microns ( more than twice as small as the pits on DVD ) Track-pitch is : 0.32 microns (0.74 microns in DVD) Data transfer rate : 36 Mbps ( where DVD read data at 10Mb/s.)
LASER Closer the pits , more precise laser is required . BLUE-VIOLET laserGallium Nitride LED Semiconductor diode which reads Blu Ray disc
WORKING Places data on top of polycarbonate layer Prevents birefringence Prevents disc tilt Birefringence & disc tilt are the drawbacks of DVD WHAT ARE BIREFRINGENCE &DISC TILT?
DVD Data is sandwiched between twopolycarbonate layers, each 0.6 mm thick.
BIREFRINGENCE Refraction of laser light due to toppolycarbonate layerDISC TILT Distortion of laser beam due to unevensurface
ADVANTAGES Hard coating technologies make Blu ray Disc most durable It provides resistance to:- Finger prints Marks Scratches Dust• Faster data seek times– due to high density Much more ROBUST than today’s polycarbonate – based CD/DVD
Blu Ray Usage Recording media Video games Used by Music companies Watching movies DISADVANTAGE: EXPENSIVE