1. -P.SAILAJA

2. WHAT IS BLU RAY DISC???
 HIGH DENSITY OPTICAL DISC STORAGE
MEDIUM
 TO SUPERSEDE DVD FORMAT
 STORES HIGH DEFINITION CONTENT

3. NOMENCLATURE
 It utilizes blue-violet laser
 BLUE + LASER = BLU RAY
(optical
ray)
 ‘e’ dropped---- for trademarking

4. HISTORY
FIRST GENERATION
 COMPACT DISC(CD):
CAPACITY : 650/ 700 MB
WAVELENGTH OF LASER : 780nm
COLOUR OF LASER : RED

5. SECOND GENERATION
DIGITAL VERSATILE DISC(DVD):
CAPACITY : 4.7 GB
WAVELENGTH OF LASER : 650nm
COLOUR OF LASER : RED

6. NEED FOR BLU RAY DISC
 No particular storage for HD format
To store HD content big size DVDs were
used
 Shuji Nakamura invented the violet-blue
laser diode which was apt for a Blu-Ray Disc.

7. THIRD GENERATION
BLU RAY DISC
CAPACITY : 25/50 GB
WAVELENGTH OF LASER : 405nm
COLOUR OF LASER : BLUE-VIOLET

8. DVD & BLU RAY DISC- SAME PHYSICAL SIZE

9. BLU RAY DISC ASSOCIATION
Developed blu ray disc format

10. TYPES OF BLU RAY DISC
• SINGLE LAYER
25/27 GB
•DOUBLE LAYER
• 50 GB
MULTI LAYER
> 50 GB

11. FORMATS OF BD
4 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.

12. 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.

13. THE TECHNOLOGY
 Disc stores digitally
encoded data in PITS.

14. 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

15. 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.)

16. LASER
 Closer the pits , more precise laser is required .
 BLUE-VIOLET laser
Gallium Nitride LED
 Semiconductor diode which
reads Blu Ray disc

18. CONSTRUCTION

19. CONSTRUCTION

20. 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?

21. DVD
Data is sandwiched between two
polycarbonate layers, each 0.6 mm thick
.

22. BIREFRINGENCE
Refraction of laser light due to top
polycarbonate layer
DISC TILT
Distortion of laser beam due to uneven
surface

23. 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

24. Blu Ray Usage
 Recording media
 Video games
 Used by Music companies
 Watching movies
DISADVANTAGE:
 EXPENSIVE