Lacie BLU-RAY MEDIA, D2 BLU-RAY DRIVE User Manual
BD DVD CD
405nm
Wavelength
Cover Layer: 0.1 mm
Recording Layer Recording Layer
650nm
Wavelength
720nm
Wavelength
Optical Lens: 0.85 NA
Substrate: 1.1 mm
Substrate: 0.6mm
Substrate: 0.6mm
Substrate: 1.2mm
Optical Lens: 0.6 NA
Optical Lens: 0.45 NA
Recording Layer
LaCie d2 Blu-ray Drive
White Paper
HOW CAN 50GB BE STORED ON ONE DISC?
The structure of a Blu-ray (BD) disc fundamentally differs
from the structure of a DVD/CD. Because the data layer
on a Blu-ray disc is placed much “closer” to the laser
lens than on a DVD/CD, the laser beam provides more
precision. (fig. A)
Structural Designs of Disc Formats
fig. A
Also, because the disc’s first data layer is positioned at
the very top of the disc structure, there is more space left
underneath it for an additional layer, allowing for storage
on 2 layers (50GB).
HOW CAN THE LACIE d2 BLU-RAY DRIVE READ
AND WRITE TO BD/DVD/CD?
The optical parameters of BD, DVD and CD are different
(see previous paragraph). Therefore, the LaCie d2 Blu-ray
Drive combines:
- 3 Laser Diodes: one for each disc format
- 2 Lenses: one to write/read BD, one to write/read DVD/CD
WHY ARE BLU-RAY DISCS A SAFE, LONG-TERM
ARCHIVING SOLUTION?
The LaCie d2 Blu-ray Drive uses a blue-violet laser
and improved lens specifications (wavelength, NAnumerical aperture) allowing for a laser beam focus that’s
approximately one-fifth smaller than the red laser used to
burn DVDs.
This combination enables recording much smaller and
higher density pits onto BD discs. (fig. B)
CD, DVD and Blu-ray (BD) Storage Densities
CD 0.7 Gbyte
Track Pitch: 1.6 micron
Minimum Pit Length: 0.8 µm
Storage Density: 0.41 Gb/inch2
DVD 4.7 Gbyte
Track Pitch: 0.74 micron
Minimum Pit Length: 0.4 µm
Storage Density: 2.77 Gb/inch2
Blu-ray Disc 25 Gbyte
Track Pitch: 0.32 micron
Minimum Pit Length: 0.15 µm
Storage Density: 14.73 Gb/inch2
fig. B
The recording layer of a Blu-ray disc is located just under
the cover layer, which is only 0.1 mm thick.
To protect it and thus ensure long-term Blu-ray disc
content reliability, several technologies have been
developed by media manufacturers:
- Stable Writing & High Protection: The cover layer is
applied precisely and smoothly to the disc, not to deflect the
sensitive laser beam when reading or writing. It also ensures
evenness in recording layer protection.
- Scratch-Free Protective Layer: Blu-ray standards stipulate
one scratch-free top layer that is dirt and dust repellent and
prevents fingerprint smudges from interfering with the
disc’s readability.
- New Light-Resistant Recording Layer: Made up of an
inorganic material that is different from DVD/CDs, which
use pigments, BD’s recording layer is less sensitive to
ultraviolet light.
- Overwriting Reliability: Changed material in the recording
layer allows rewriting on a BD-RE up to 10,000 times with
stable quality.
LaCie d2 Blu-ray Drive White Paper
WHICH HD VIDEO COMPRESSION
STANDARDS DOES BLU-RAY COMPLY WITH?
HD video is a data-hungry application. MPEG-2 codec
allows storing a full-length feature film in HD, plus bonus
material on just one 25GB disc. MPEG-4 AVC (H.264)
and VC1 are two other video compression standards that
can match the best possible MPEG-2 quality at up to half
the data rate.
Since the LaCie d2 Blu-ray Drive complies with each of
these, the user can choose the most suitable one for a
particular application.
Typical HD Video Transfer Rates:
MPEG-2 = 21 Mbits/s
MPEG-4 AVC (H.264) = 8 Mbits/s
VC1 = 8Mbits/s
LaCie is a global leader in manufacturing top-of-the-line
solutions that are often first-to-market, constantly raising the
bar and re-establishing industry standards.
Through a combination of cutting-edge engineering and a
rich 16-year history of unique design aesthetics, LaCie has
earned an excellent reputation for producing solutions that
are the perfect synthesis of form and function. Our hard
drives, media drives, displays, and accessories are created to
enhance and expand your computing environment, no matter
its platform or configuration.
Please visit our website: www.lacie.com for more information.
LaCie • 22985 NW Evergreen Parkway, Hillsboro, OR 97124 USA
LaCie S.A. • 17, rue Ampère 91349 Massy Cedex France
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