A.Arundeep
ECE IV Year
[email protected]
INTRODUCTION
It is the term given to any form
of optical data storage in which information
can be recorded and/or read with three
dimensional resolution.
This innovation has the potential to
provide terabyte-level mass storage on DVDsized disks.
Data recording and readback are achieved
by focusing lasers within the medium.
HISTORY
In the 1970s, Valeri Barachevskii
demonstrated that this photochromism could
be produced by two-photon excitation.
Finally at the end of the 1980s Peter T.
Rentzepis showed that this could lead to threedimensional data storage
Various storage devices till date
I Generation :
Compact Disc(CD) – 650/700MB
Laser wavelength – 780nm
Color of laser – RED
II Generation :
Digital Versatile Disc(DVD) – 4.7GB
Laser Wavelength - 650nm
Color of laser - RED
III Generation :
Blu ray Disc(BD) - 25/50GB
Laser wavelength – 405nm
Color of laser - BLUE
PROCESS OF WRITING DATA
‫ ﻂ‬Non resonant multiphoton absorption
‫ ﻂ‬Sequential multiphoton absorption
‫ ﻂ‬Microholography
‫ ﻂ‬Recording during manufacturing
Invented by SHVJI NAKAMURA of NICHA
Corporation.
It has the main use of High Definition video & Data
Storage.
The name Blu-ray Disc derives from the blue-violet
laser used to read the disc.
BD TECHNOLOGY
Pits-Spiral grooves that run from center of the disc to its edges.
Bumps-Other sides of these above edges.
Track Pitch-It is the distance between the two tracks(of pits) on
the surface.
DATA IS STORED IN THE PITS
DISC STRUCTURE
SPECIFICATIONS OF BD
Laser and optics
Hard coating technology
Recording Speed
Drive
speed
Data rate
Theoretical write time for BD
(in minutes)
Mb/sec
MB/sec
Single layer
Double layer
1x
36
4.5
90
180
2x
72
9
45
90
4x
144
18
22.5
45
6x
216
27
15
30
8x
288
36
11.25
22.5
12x
432
54
7.5
15
FORMATS
BD-ROM (read only) : For pre-recorded content
BD-R (Recordable) : For storing HD data on the disc
BD-RW (Rewritable) : For PC data storage
BD-RE (Rewritable) : For HD TV storage
CD/DVD vs. BD
BD
Data is stored on the top of
the 1.1mm thick polycarbonate
layer
DVD
Data is sandwiched between
two 0.6mm thick poly
carbonate layers.
Numerical Aperture is 0.85
Numerical Aperture is 0.65
Track Pitch 0.32 micron
Track Pitch 0.74 micron
Storage capacity is 25/50GB.
Storage capacity is 15/30GB
Image resolution is HIGH
Image resolution is POOR
Pictorial & Graphical comparison
ADVANTAGES
 Instantly skip to any part of the disc.
 Record HDTV without any quality loss.
Multi-tasking.
Automatically search for an empty space.
Higher density enables better data seek times.
and many more……
FUTURE IN BD