Fluorescent Multilayer Disk (FMD) technology allows for over 100 layers in a disk by using fluorescent materials that emit different wavelengths of light for each layer. This overcomes limitations of reflective DVDs which degrade after only a few layers. FMD prototypes demonstrated 50GB storage using red lasers, with plans for 140GB using red lasers and over 1TB using blue lasers. FMD works by filling pits with fluorescent materials that convert laser light to a distinct emitted wavelength, allowing layers to be read through the transparent disk. The main limitation is thickness, not interference like in DVDs.

1. ECE FLUORESCENT MULTYLAYER DISK
1.INTRODUCTION
Fluorescent Multilayer Disc, abbreviated as FMD, is a data storage medium that
follows the idea previously used in DVDs, making multiple layers to get more data on
one disc, but takes the idea to a new level. Because the normal reflective layers were too
limiting, making it nearly impossible to get more than two layers on a disc, Constellation
3D decided to find a new way to reflect the light that would not interfere with other
layers. To do this, they have a different fluorescent material in each layer which reflects a
different frequency of light than the other layers, making it possible to shine the light
through the disc and read the proper frequency for the expected layer. Because of this, the
main limitation on the number of layers, besides how many different materials can be
found to be used, would be to keep the disc from being too thick.
A 50 GB prototype disc was demonstrated at the Comdex industry show in November
2000. First generation FMDs were to have roughly 100 GB per disc.
After the shutting down of Constellation 3D due to a scandal and the company
consequently running out of money, a new company called D Data Inc. was formed
which acquired the entire patent portfolio of Constellation 3D in 2003. The company is
determined to bring multilayer optical disc technology to the market .
Compact discs were a revolutionary product at its time and influenced many
spheres of human activity. People started recording music of high quality, which didn't
get worse with the time as it happens to be on tape. As soon as CDs appeared in computer
industry they immediately became an undoubted helper both for users and for
programmers. The latter were able to increase volume of their program products by
adding video and audio elements etc. FMD, which can provide us with a staggering 140
GB of storage space, seems to be an enticing solution for the storage-hungry masses. The
company Constellation 3D demonstrates a new format: FMD (Fluorescent Multilayer
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Disk), which can provide us with a staggering 140 GB of storage space, seems to be an
enticing solution for the storage-hungry masses.
Constellation 3D's technology implements the concept of the volumetric
storage of information. Data is recorded on multiple layers located inside a disc or a card,
as opposed to the single layer method available in compact discs, and double layer
method available in DVD’s. The recording, reading and storing of the information is
accomplished through the use of fluorescent materials embedded in pits and grooves in
each of the layers. The fluorescent material emits radiation when excited by an external
light source. The information is then decoded as modulations of the intensity and color of
the emitted radiation.
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2. DEVELOPMENT AND OPERATING PRINCIPLES
2.1 DEVELOPMENT
A 50 GB prototype disc was demonstrated at the COMDEX industry show in
November 2000. First generation FMDs were to use 650 nm red lasers, yielding roughly
140 GB per disc. Second and third generation FMDs were to use 405 nm blue lasers,
giving capacities of up to a terabyte.
2.2 OPERATING PRINCIPLES
The pits in an FMD are filled with fluorescent material. When coherent light from
the laser strikes a pit the material glows, giving off incoherent light of a different
wavelength. Since FMDs are clear, this light is able to travel through many layers
unimpeded. The clear discs, combined with the ability to filter out laser light (based on
wavelength and coherence), yield a much greater signal-to-noise ratio than reflective
media. This is what allows FMDs to have many layers. The main limitation on the
number of layers in an FMD is the overall thickness of the disc.
Fig2.1 Layers of disk
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2.3 FLUORESCENT MULTILAYER
The concept of multi-layer, fluorescent cards/discs (FMD/C) is a unique
breakthrough, solving the problems of signal degradation. Here, the storage layer is
coated with a fluorescent material. When the laser beam hits the layer, fluorescent light is
emitted. This emitted light has a different wavelength from the incident laser light -
slightly shifted towards the red end of the light spectrum and is incoherent in nature, in
contrast to the reflected light in current optical devices. The emitted light is not affected
by data or other marks, and transverses adjacent layers undisturbed. In the read out
system of the drive the light is filtered, so that only the information-bearing fluorescent
light is detected, thus reducing the effect of stray light and interference. Theoretical
studies, confirmed by experimental results, have shown that in conventional reflection
systems the signal quality degrades rapidly with the number of layers. In fluorescent read
out systems, on the other hand, the signal quality degrades much more slowly with each
additional layer .Research has shown that media containing up to a hundred layers are
currently feasible, thereby increasing the potential capacity of a single card or disk to
hundreds of Gigabytes. Use of blue lasers would increase the capacities to over 1
Terabyte.
2.4 FLUORESCENT MATERIAL
The fluorescent material . arguably, the .main ingredient. of FMD technology
converts incident (incoherent) laser light into incoherent fluorescent light. C3D has
several material formulations. The most-developed material is used in read-only discs.
Writable (recordable) and re-writable formulations (and their corresponding drives) have
also been demonstrated using proprietary photo chromic compound.
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3. TECHNOLOGICAL PROCESS
Technological process of FM discs is divided into two types: In the first one there used a
method of hot stamping.
3.1 Hot Stamping:
Each layer is reached by pressing of polycorbone layer with two stamps (Master-
copies) at high temperature. So we receive one layer with two informational sides. Then,
pits starts being fill with fluorescent material. And when it becomes hard the
informational layers are pressed.
In the picture you can see a structure of a 7-layer disc produced according to the
described method.
Fig 3.1 seven layer FDM
The second method uses a process of photo polymerization when a multiple disc
is reached by stacking of discs one after another which are made from thin informational
layers.
Manufacture of one informational layer lies in manufacture of plastic film with
definite optical characteristics. The film is 25 to 30 micron in width. The film which will
get information soon is either stamped or cut out with a laser. After that the film is
installed on an external surface of a nickel matrix that carries a negative copy of
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produced informational layer. While rotating, photopolymer matter is evenly brought in
in the space between stamp surface and plastic film. Later, when the photopolymer matter
becomes hard the film get detached from the stamp surface. The base plate now contains
pits of definite geometry. A pit's geometry is better in terms of quality than that received
when manufacturing matrices for CD or DVD since those technologies use a process of
stamping of pits. When a layer with the required position of pits is ready, they are filled
with fluorescent material (it covers evenly the whole informational side).
After that the surface is processed chemically in order to reach necessary contrast
of pits and flats. Then, in order to check the copy for different defects, photoelements get
excited and the whole picture is analyzed with the help of CCD cameras. After that the
layers are "stuck" to the base plate 0.6 mm in width. And all this is covered with a
protective layer which can be used for graphics decoration. In order to prevent a physical
contact with informational layers on the edge of the disc this area is filled as well with
polymeric material, like in CD or DVD technologies.
3.2 Hot-Embossing:
Using hot metal stompers, thin polycarbonate sheets are embossed on both sides.
After the sheets cool, the embossed pits are filled with fluorescent dye. After the dye is
cured, the individual sheets are stacked and bonded together under pressure. The result is
a storage media having multiple layers: a Fluorescent Multilayer Disc.
3.3 Photo-Polymerization (2P) Process:
This method, in which layers are sequentially replicated by creating .thin
replicas., will eventually allow FMD to incorporate up to 100 layers .
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3.2 Photo polymerizations
4. COMPARISION WITH DVD AND CD
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4.1 CD (COMPACT DISK):
Compact disc (CD) is a digital optical disk data storage format. The format was
originally developed to store and play only sound recordings but was later adapted for
storage of data (CD-ROM). Several other formats were further derived from these,
including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video
Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, Pictured, CD-i,
and Enhanced Music CD. Audio CDs and audio CD players have been commercially
available since October 1982.
Standard CDs have a diameter of 120 millimeters (4.7 in) and can hold up to
about 80 minutes of uncompressed audio or about 700 MB of data. The Mini CD has
various diameters ranging from 60 to 80 millimeters (2.4 to 3.1 in); they are sometimes
used for CD singles, storing up to 24 minutes of audio or delivering device drivers.
Fig 4.1 CD
4.2 DVD:
DVD (sometimes explained as "digital versatile disc" or "digital video disc") is a
digital optical disc storage format, invented and developed by Philips, Sony, Toshiba, and
Panasonic in 1995. DVDs can be played in multiple types of players, including DVD
players.
4.3 FMD VS DVD AND CD:
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TABLE 4.1 Differences
5. ADVANTAGES AND APPLICATIONS
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5.1 ADVANTAGES
1. The multi-layer system is optically transparent and homogeneous.
2 Low absorption in each layer.
3. No absorption for the emitted signal fluorescent light.
4. Lower than CD/DVD sensitivity to imperfections in media and drives. The fluorescent
technique does not depend on interference effects and requires less stringent
manufacturing tolerances for media and drives.
5. The emitted fluorescent light from any given layer is non-coherent, eliminating the
problem of parasite interference.
6. The limited lateral spatial resolution for this system is twice that for coherent light
based systems .
7. FMD technology is compatible with current CD and DVD formats, having the capacity
to handle the same data rates over each of its layers
8.Prevents problem of interference since it uses an incoherent fluorescent light.
5.2 APPLICATIONS
1.storage of very high detailed architecture of maps
2.digital cinema films ,HDTV players
3.internet connect streaming and data backup storage
5.2 SECURITY
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FMD will offer an extraordinary amount of security. In addition to complying
with the newest and most sophisticated encryption technologies, FMD.s unique dye
chemistry will offer much greater control over access to intellectual property. In the
digital cinema realm, for example, FMD.s capacity of each frame (there are 24 frames
allows for digital watermarking per second). Dyes can even be customized to work
exclusively with FMD players used in cinemas, rendering stolen copies inaccessible to
those using consumer drives. As for protection from mass-duplicating pirates, dyes can
be designed to last only for a specific number of plays or limited amount of time (Cohen,
2001). One can easily see that FMD.s
security options will be useful beyond cinema. Governments, businesses large and small,
and consumers will all benefit from them
6.CONCLUSION
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The rapid technological development that is taking place in storage devices has
also made the man think about the needs and the requirements for the storage devices.
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.
7.REFERENCES
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1 . www.en.wikipedia.org/ wiki.
2 .www.ixbtlabs.com/articles 3.www.seminartopic.org.
3.http://news.bbc.co.uk/hi/english/entertainment/newsid_1190000/1190724.stm.
4.http://www.fmdinsider.com. February 1, 2002.
5. Sandler, In golf. (1999). White Paper . Fluorescent Multilayer optical storage.
BIO-DATA
Name : R.MAHESH
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Father Name : CHANDRASHEKAR
Roll No. : 11RR1A0444
Date of Birth : 11/07/1993
Email : theprincemahi92@gmail.com
Phone No. : 9642222061
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