BYVINOD KUMAR.M

HISTORY1st GENERATION:Compact disc (CD): --- 650/700 MBWavelength of laser which reads data: 780 nmColor of laser: Red2nd GENERATION:Digital versatile disc (DVD): --- 4.7 GBIt offers high quality sound and video than CD.Wavelength of laser which reads data: 650 nmColor of laser: Red

HISTORY3rd GENERATION:Blu-ray disc (BD): --- 25/50 GB-Next generation optical disc format.

-Wavelength of laser which reads data: 405 nm-Color of laser: Blue-violet which was

developed bySHUJI NAKAMURA at NICHIA CORPORATION

THE NAMEThe blu-ray name is a combination of “blue”,

for the color of the laser that is used and “ray” for optical ray.

The “e” in “blue” was purposefully left off, according to the manufacturers, because an everyday word cannot be a trademark.

TYPES OF BD:SINGLE LAYER :- Can hold data up to 25/27 GB that means 2

hrs of HD video or about 13 hrs of standard video.

DOUBLE LAYER :- Can hold data up to 50 GB that means 4.5 hrs

of HD video or more than 20 hrs of standard video.

SISE OF THE DISC

THE TECHNOLOGY

So, 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

Laser needed : blue-violet laser (405 nm)

Data transfer rate : 36 Mbps

•The Blue-laser’s shorter wavelength makes it possible to store more information on a 12 cm CD/DVD size disc. The minimum spot size on which a laser can be focused is limited by diffraction ,and depends on the wavelength of the high and the numerical aperture of the lens used to focus it.

THE TECHNOLOGYPits : spiral grooves

that run from the centre of the disc to its edges

Track pitch : it is the distance between the two tracks (of pits) on the surface.

BLU RAY ‘S DURABILITY ADVANTAGEVarious hard coating technologies make

Blu ray disc most durable and family -friendly”

Hard-coating technology provides resistance to:

- Finger prints

- Marks

- Scratches

- Dust

FEATURES OF BDWith BD we can:Record HDTV without any quality lossInstantly skip to any spot on discRecord one program while watching other on the

discCreate playlistsEdit or reorder programs recorded on discAutomatically search for an empty space on the

disc to avoid recording over a programAccess to web to download subtitles and other

extra featuresAnd many more…

Queries?