04-06-2012, 10:38 AM
FLUORESCENT MULTILAYER DISC
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FLUORESCENT MULTILAYER DISC (FMD)
Fluorescent Multi-Layer Discs (FMDs)
are a new technology being developed
by Constellation 3D Inc.
Implement the concept of volumetric
storage of information.
FMD stores digital data in three
dimensions.
It is an optical data storage format
similar in size and appearance to
regular CD-ROMs and DVDs.
FMD is a readable and re-writable disc.
Max data transfer rates are
approximately 1GB/sec.
FMD is a transparent disc.
It consists of multiple data layers.
Data is recorded on multiple layers
inside a disc.
Capacity of each data layer is 4.7
GB.
Each data layer consists of pits &
groves.
Pits are embedded with transparent
fluorescent material.
Recording, reading & storing of data
is accomplished by fluorescent
material.
Fluorescent material emit radiation
when exited by an external light
source.
FMD can hold up to 20-140GB of
data on 12-30 data layers, with total
thickness under 2mm.
OVERVIEW ON CD-ROM
Single data layer
Data layer - Reflective (Aluminum)
Data bits stored in the form of
physically molded pits.
Smooth area surrounding pits are
called lands.
Red laser is used to read data.
Storage capacity : 650MB.
Data access speed range: 80 to 120ms
Max data transfer rate: 5MB/sec.
OVERVIEW ON DVD-ROM
DVD consists of 2 data layers.
Data layer - Reflective (Aluminum)
Distance between recording tracks: less than
half of CDs.
Pit size is less than half of that of CD-ROMs.
Red laser is used to read data.
Require reduced laser wavelength to read small
size pits.
Storage capacity : 40GB
TECHNOLOGICAL OVERVIEW OF FMD
FMD is a transparent disc.
No reflective layer like CD/DVD.
Technology in CD:
Beam of laser hits on data layer
It reflects from aluminum data
layer
Fixed with a detector-receiver
Technology in FMD:
No reflected laser beam.
Principle of operation based on a
phenomenon “photochromism”
An organic material called ‘stable
photochrome’ is used as fluorescent
material.
Photochrome initially doesn't possess
fluorescent properties.
Photochrome when acted upon by
laser beam starts photo chemical
reactions & obtain the fluorescent
properties.
Simulation of fluorescent material
by laser to produce incoherent
light.
Emission of data stored incoherent
light.
Incoherent light passes through
adjacent data layers without
getting distorted.
Filtration of emitted light before it
reaches the drive's detector.
Only the data-carrying fluorescent
light passes after filtration.
Filtration reduces the effect of stray light and interference.
This fluorescence light is caught up by the photo receiver.
And assigns a value “1”.
FMD DISC DRIVE
TECHNOLOGICAL PROCESS OF MANUFACTURE
Two types of technological process
for FMD manufacture.
Hot Stamping
Photo Polymerization
Hot Stamping
Pressing of polycarbon sheets
with two stamps at high
temperature.
Formation of a layer with two
information sides.
Filling pits with fluorescent material.
Pressing of informational layers when material gets hard.
Photo Polymerization
For production of multiple disc by stacking of discs one after
other.
Manufacture of thin plastic film for informational layer.
Plastic film is of 25-30 micron width.
Film is stamped & then installed on external surface of a nickel
matrix that carry negative copy of produced information layer.
p Pit formation: On rotation of matrix, photopolymer matter is evenly
brought in space between stamp surface & plastic film.
Film get detached from stamp surface when it gets hard
The base plate now contain pits of definite geometry.
When a layer with required position of pit is ready, they are filled with
fluorescent material (covers whole informational side)
Chemical processing & defect checking.
Layers stuck to the base plate 0.6mm in width
Finally covered with a protective layer
FMD RECORDING
Technology used: WORM (Write Once
Read Many)
A series of rewritable discs called FMD
WORM
Two rules to be followed while recording :
The write laser should able to turn the
fluorescence on or off.
Threshold power of laser for recording
& less power for reading.
Recording principles in FMD
Thermal:
Usage of materials that possesses fluorescent properties
from beginning (logical one).
When recording the segments, which are thermally acted
upon with laser, the fluorescent properties are lost (logical
zero)
Chemical:
Usage of a material that doesn't possess fluorescent
properties form the beginning.
When acting upon with a laser a photochemical reaction
starts, and the material gets fluorescent properties.
a low power laser is enough, or even a usual LED
FMD READ DEVICE
Drives for FMD can easily understand
CD/DVD.
FMD drives are similar to CD/DVD.
Three types of reading:
Successive reading
Successive-parallel reading
Parallel reading
Parallel Reading
A sequence of bits is recorded not
along a track but deep into layers.
Reading process is carried out with the help of a photosensitive
element (an array of CCD cameras)
Device can read low-power fluorescence of several tens MHz.
Reading speed reaches 1 gigabit/s
Mechanical speed of the drive is 450 times lower than that of DVD.
12x enlargement of FMD segment
received with CCD cameras
Signals received from each element
of CCD array
ADVANTAGES OF FMD
Increased disc capacity
Quick parallel access and retrieval of information
Media tolerances & Usage flexibility
Optically transparent and homogeneous multilayer system
Emission of incoherent light eliminates interference.
Compatible with present CD/DVD formats & ability to withstand
more extreme conditions.
Unique dye chemistry of FMD offers an extraordinary amount of
security.
Cost of production of FMD discs is relatively cheap.
COMPARISON OF CD,DVD,FMD
Parameter CD DVD FMD
Disc diameter, mm 120 120 130
Capacity, GBytes 0.64 17.4 50.8
Number of layers 1 2 (each side) 12
Distance between layers, Micron - 40 25/5
Total width of informational
layers, Micron
0.11 2 275
Format CD DVD Modified DVD
Distance between tracks, Micron 1.6 0.74 0.8
Optical system wavelength, NM 780 635-650 532
APPLICATIONS
Storage of a very high detailed archive
of maps.
Ability to store a large amount of files
in uncompressed format.
Ability to store the whole of a series
of TV programme (eg, 20 episodes,
each an hour long).
Digital cinema film, HDTV players.
Internet content streaming and data
backup storage.
CONCLUSION
Man’s need for additional storage space is increasing .
The FMD Digital Cinema disc has the potential to provide a
secure, removable, single disc distribution method.
The FMD can provide us with a staggering 140 GB of
storage space seems to be an enticing solution for the storage
- hungry masses.