3D OPTICAL DATA STORAGE TECHNOLOGY

A.ArundeepECE IV Yeararundeepreddy@gmail.com

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 DVD-sized disks.

Data recording and readback are achieved by focusing lasers within the medium.

INTRODUCTION

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 three-dimensional 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

Non resonant multiphoton absorption ط

Sequential multiphoton absorption ط

Microholography ط

Recording during manufacturing ط

BLU RAY DISC 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 SpeedDrive 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

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

FORMATS

CD/DVD vs. BDBD

Data is stored on the top of the 1.1mm thick polycarbonate layer

Numerical Aperture is 0.85

Track Pitch 0.32 micron

Storage capacity is 25/50GB.

Image resolution is HIGH

DVD Data is sandwiched between two 0.6mm thick poly carbonate layers.

Numerical Aperture is 0.65

Track Pitch 0.74 micron

Storage capacity is 15/30GB

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

Than Q

QUERIES ??????