22009086 Seminar Report on Blu Ray Disc by Sonal Singh

8/3/2019 22009086 Seminar Report on Blu Ray Disc by Sonal Singh

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DEPARTMENT OF ELECTRONICS &

COMMUNICATION

SEMINAR REPORT

ON

BLU-RAY DISC

SUBMITTED TO :- SUBMITTED

BY :-

Mr. Rohit Tripathi Sonal Singh

(Seminar Incharge) EC 4th year

(0616431111)

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ACKNOWLEDMENT

I would like to thank everyone who helped to see this seminar

to completion. In particular, I would like to thank my seminarincharge Mr. Rohit Tripathi for his moral support and

guidance to complete my seminar on time.

I express my gratitude to all my friends and classmates for

their support and help in this seminar.

Last but not the least I wish to express my gratitude to God

almighty for his abundant blessings without which this seminar

would not have been successful.

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ABSTRACT

Optical discs share a major part among the secondary storage

devices. Blu-ray disc is a next generation optical disc format.

The technology utilizes a blue laser diode operating at a

wavelength of 405nm to read and write data. Because of the

blue laser it can store enormous amount of data than was ever

possible.

Data is stored on a BD in the form of tiny ridges on the surface

of an opaque 1.1mm thick substrate. This lies beneath a

transparent .1mm protective layer. With the help of Blu-ray

recording devices it is possible to record upto 2.5 hrs of very

high quality audio and video on a single BD.

Blu-ray also promises some added security, making ways for

copyright protections. Bd can have a unique ID written on them

to have copyright protection inside the recorded streams.

Blu-ray Disc takes the DVD technology one step further just by

usin g a laser with a nice colour.

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INDEX

INTRODUCTION..1-5

1. HISTORY OF BLU-RAY DISC..6

1.1 FIRST GENERATION.6

1.2 SECOND GENERATION.6

1.3 THIRD GENERATION6-7

2. GLOSSARY OF TERMS

2.1 HDTV.8

2.2 MPEG8-9

2.3 GIGABYTE.9

2.4 LAYER9-102.5 SDTV.10

2.6 NUMERICALAPERTURE10-112.7 BLUE LASER11-12

3. OPTICAL DATA STORAGE FOR DIGITAL VIDEO

3.1 INTRODUCTION16

3.2 PARAMETERS FOR HD VIDEO STORAGE WITH OPTICAL

DISCS.16

3.2.1 OPTICAL PARA METER16-223.2.2 DISK STRUCTURE PARAMETERS22-24

3.2.3 DATA MANAGEMENT PARAMETERS.24-26

4. DIFFERENT FORMATS OF BD27

5. TWO VERSIONS OF RECORDING28

5.1 ONE TIME RECORDING..28

5.2 RECORD MANY TIMES.28-29

6. BLU-RAY DISC STRUCTURE.30-31

7. BLU-RAY DISC CHARACTERISTICS..337.1 LARGE RECORDING CAPACITY33

7.2 HIGH SPEED33

7.3 RESISTANCE TO SCRATCHES

7.4 AND FINGERPRINTS..33

8. BLU-RAY

FOUNDERS.34

9. CHARACTERISTICS OF IDEAL COMMUNICATION..35

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10.HOW DOES BLU-RAY DISC WORK?

36-37

11.COMPARISONS

.38

12.BLU-RAY DISC AND HD-DVD

39-40

13.ADVANTAGES OF

BD.41-42

14. THE

IMPACT..........43

15.APPLICATIONS

44

15.1 HIGH DEFINITION TELEPHONE RECORDING44

15.2 HIGH DEFINITION VIDEO DISTRIBUTION45

15.3 HIGH DEFINITION CAMCORDER ARCHIVING45

15.4 MASS DATA

STORAGE.46

15.5 DIGITAL ASSET MANAGEMENT AND

PROFESSIONAL

STORAGE

46

16.REQUIREMENTS

47

17.CHALLENGES

.47

18.FUTURE

DEVELOPMENTS.48

19.CONCLUSION

.49

20.REFERENCES

50

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Introduction

Tokyo Japan, February 19, 2002: Nine leading companies

announced that they have jointly established the basic

specifications for a next generation large capacity optical disc

video recording format called "Blu-ray Disc". The Blu-ray Disc

enables the recording, rewriting and play back of up to 27

gigabytes (GB) of data on a single sided single layer 12cm

CD/DVD size disc using a 405nm blue-violet laser.

By employing a short wavelength blue violet laser, the Blu-ray

Disc successfully minimizes its beam spot size by making the

numerical aperture (NA) on a field lens that converges the laser0.85. In addition, by using a disc structure with a 0.1mm optical

transmittance protection layer, the Blu-ray Disc diminishes

aberration caused by disc tilt. This also allows for disc better

readout and an increased recording density. The Blu-ray Disc's

tracking pitch is reduced to 0.32um, almost half of that of a

regular DVD, achieving up to 27 GB high-density recording on asingle sided disc.

Because the Blu-ray Disc utilizes global standard "MPEG-2

Transport Stream" compression technology highly compatible

with digital broadcasting for video recording, a wide range of

content can be recorded. It is possible for the Blu-ray Disc to

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record digital high definition broadcasting while maintaining

high quality and other data simultaneously with video data if

they are received together. In addition, the adoption of a

unique ID written on a Blu-ray Disc realizes high quality

copyright protection functions.

The Blu-ray Disc is a technology platform that can store sound

and video while maintaining high quality and also access the

stored content in an easy-to-use way. This will be important in

the coming broadband era as content distribution becomes

increasingly diversified. The nine companies involved in the

announcement will respectively develop products that take full

advantage of Blu-ray Disc's large capacity and high-speed data

transfer rate. They are also aiming to further enhance the

appeal of the new format through developing a larger capacity,

such as over 30GB on a single sided single layer disc and over

50GB on a single sided double layer disc. Adoption of the Blu-

ray Disc in a variety of applications including PC data storage

and high definition video software is being considered.

Concept of the format establishment :

To realize the large capacity with 12cm disc- More than 2-hour high definition video recording

- High capacity of more than 4-hour recording by double

layer technology.

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To cope with digital broadcasting- High compatibility with digital broadcasting

- To prevent illegitimate duplication of contents

To enhance the Blu-ray Disc world- Adoption of the Blu-ray Disc in variety of media and

applications

Main Features of physical format:

Large recording capacity up to 27GB:By adopting a 405nm blue-violet semiconductor laser, with a

0.85NA field lens and a 0.1mm optical transmittance protection

disc layer structure, it can record up to 27GB video data on a

single sided 12cm phase change disc. It can record over 2

hours of digital high definition video and more than 13 hours of

standard TV broadcasting (VHS/standard definition picture

quality, 3.8Mbps)

Easy to use disc cartridge:

An easy to use optical disc cartridge protects the optical disc's

recording and playback phase from dust and fingerprints

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High-speed data transfer rate 36Mbps:It is possible for the Blu-ray Disc to record digital high definition

broadcasts or high definition images from a digital video

camera while maintaining the original picture quality. In

addition, by fully utilizing an optical disc's random accessing

functions, it is possible to easily edit video data captured on a

video camera or play back pre-recorded video on the disc while

simultaneously recording images being broadcast on TV.

Recording format:

Like the DVD, the Blu-ray disc uses phase change recording. This

must be good news for those who plan to make the new format

compatible with its wildly popular predecessor. This recording

format will also makes a two-sided disc easily realizable because

both writing and reading can be executed by a single pickup.

Multiplexing:Blu-ray disc utilizes global standards like MPEG-2 Transport Stream

compression technology for video and audio multiplexing. This

makes it possible for a Blu-ray Disc to record high definition

broadcasting and other data simultaneously with video data if they

are received together. Data captured on a video camera while

recording images being broadcast on TV can also be edited

simultaneously.

Main Features Of Logical format :

Highly compatible with digital broadcasting :9


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MPEG2 transport stream compression technology for video

recording can record digital broadcasting including HDTV while

maintaining its original picture quality.

Best data structure for disc recordingAchieving improvement of searching, easy editing functions

and play a list playback functions by adapting logical data

structure making the best use of random accessing.

File system for HDTV real time recordingAdapting the file system which can achieve high bit rate

recording and playback of HDTV and best use of disc space

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1.History of Bluray Disc

1.1 First Generation

When the CD was introduced in the early 80s, it meant an

enormous leap from traditional media. Not only did it offer asignificant improvement in audio quality, its primaryapplication, but its 650 MB storage capacity also meant a giantleap in data storage and retrieval. For the first time, there wasa universal standard for prerecorded, recordable andrewritable media, offering the best quality and featuresconsumers could wish for themselves, at very low costs.

1.2 Second Generation

Although the CD was a very useful medium for the recordingand distribution of audio and some modest dataapplications,demand for a new medium offering higher storage capacitiesrose in the 90s. These demands lead to the evolution of the

DVD specification and a five to ten fold increase in capacity.This enabled high quality, standard definition video distribution

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and recording. Furthermore, the increased capacityaccommodated more demanding data applications. At thesame time, the DVD spec used the same form factor as the CD,allowing for seamless migration to the next generation format

and offering full backwards compatibility.

1.3 Third Generation

Now High Definition video is demanding a new solution. Historyproved that a significant five to ten time increase in storage

capacity and the ability to play previous generation formats arekey elements for a new format to succeed. This new format hasarrived with the advent of Bluray Disc, the only format thatoffers a considerable increase in storage capacity with its 25 to50 GB data capacity. This allows for the next big application ofoptical media: the distribution and recording of High Definitionvideo in the highest possible quality. In fact, no other proposedformat can offer the data capacity ofBluray Disc, and no other format will allow for the same highvideo quality andInteractive features to create the ultimate user experience. Aswith DVD, the Blu-ray Disc format is based on the same, baredisc physical form factor, allowing for compatibility with CD andDVD. The Bluray Disc specification was officially announced inFebruary 2002. Bluray Disc recorders were first launched in

Japan in 2003.

1982 First working CD player developed by Philips. Philipsand Sony developed CD standard 12cm disk,74 minutes on a single spiral 1983 First CD players sold 1985 CDROM introduced not popular at first. Morepowerful PCs lead

to demand for multimedia, image processing and largerapplications. Growth in sales brings prices down. 1990s CDR and CDRW introduced big success. 1996 DVD introduced 1999 DVD becomes mainstream

2003 BD introduced

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2.Glossary of Terms

2.1 HDTV (High Definition Video)

This high resolution 16:9 ratio, progressive scan format cannow be recorded to standard mini DV cassettes. Consumer highdefinition cameras are becoming available but this is currentlyan expensive, niche market. It is also possible to capture videousing inexpensive webcams. These normally connect to acomputer via USB. While they are much cheaper than DVcameras, webcams offer lower quality and less flexibility forediting purposes, as they do not capture video in DV format.Digital video is available on many portable devices from digitalstills cameras to mobile phones. This is contributing to theemergence of digital video as a standard technology used andshared by people on a daily basis.

2.2 MPEG

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MPEG, the Moving Picture Experts Group, overseen by theInternational Standards Organization (ISO), develops standardsfor digital video and digital audio compression. MPEG1 with adefault resolution of 352x240 was designed specifically forVideoCD and CDmedia and is often used in CDROMs.

MPEG1 audio layer3 (MP3) compression evolved from earlyMPEG work. MPEG1 is an established, medium quality format(similar to VHS) supported by all players and platforms.Although not the best quality, it will work well on olderspecification machines.

MPEG2 compression (as used for DVD movies and digitaltelevision settop boxes) is an excellent format for distributingvideo, as it offers high quality and smaller file sizes than DV.Due to the way it compresses video MPEG2encoded footage ismore problematic to edit than DV footage. Despite this, MPEG2is becoming more common as a capture format. MPEG 2 usesvariable bit rates allowing frames to be encoded with more orless data depending on their contents. Most editing software

now supports MPEG2 editing. Editing and encoding MPEG2requires more processing power than DVD and should be doneon well specified machines. It is not suitable for internetdelivery.

MPEG4 is a set of video and audio standards intended todeliver quality video over limited bandwidths that also supporta range of other media types such as text, still image and

animation. MPEG4 offers high quality, scalable streaming overa range of bandwidths, including those provided by mobilenetworks. The standards also include components andelements that allow the viewer to interact with the picture onthe screen or to manipulate individual elements in real time.

The MPEG4 format is a container for various versions calledlayers. There are different implementations, some of which areproprietary and not compliant with the ISO MPEG4 standard. Itwas initially thought that MPEG4 would become the default

format for video over the internet. With support from Apple,Real Networks and others this may still be the case. However,

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problems over licensing costs and the lack of digital rightsmanagement in the standard made many content providersslow to embrace it. These issues are being tackled but it alsofaces competition from proprietary formats such as Windows

Media. MPEG4 is beginning to be supported in other areas suchas mobile video (3G), mobile television, settop boxes andvideo on demand (VOD).

2.3 Gigabyte (GB)

A gigabyte equals about 1,000 megabytes (MB). A Bluray Disccapable of recording 50 GB therefore stores about 50,000Megabytes

2.4 Layer

In Bluray Disc, data is recorded on a single side of the disc.However, a disc can store two data layers, both at the sameside. The readout or recording laser of the Bluray Disc devicewill first read from or record to one layer, and then refocuseson the second layer. All this is done automatically without anyuser interference. A double layer Bluray Disc can store upto 50GB of data.

2.5 SDTV

It stands for Standard Definition Television. Generic termused for conventional television sets, based on the NTSC or PALstandards. SD television consists of 480 to 570 visible lines.

2.6 Numerical Aperture and Resolution

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The numerical aperture of a microscope objective is a measureof its ability to gather light and resolve fine specimen detail at afixed object distance.

Imageforming light waves pass through the specimen andenter the objective in an inverted cone as illustrated in Figure1. A longitudinal slice of this cones of light shows the angularaperture, a value that is determined by the focal length of theobjective. The angle is onehalf the angular aperture (A) andis related to the numerical aperture through the following

equation:Numerical Aperture (NA) = n (sin )

Where n is the refractive index of the imaging medium betweenthe front lensof the objective and the specimen cover glass, a value thatranges from 1.00 for air to 1.51 for specialized immersion oils.Many authors substitute the variable for in the numericalaperture equation. From this equation it is obvious that when

the imaging medium is air (with a refractive index, n = 1.0),then the numerical aperture is dependent only upon the angle

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whose maximum value is 90. The sin of the angle ,therefore, has a maximum value of 1.0 (sin90 = 1), which isthe theoretical maximum numerical aperture of a lensoperating with air as the imaging medium (using dry

microscope objectives).

2.7 THE BLUE LASER

The laser used with the Bluray disc has a wavelength of405nm.Though the red and the green lasers were discoveredmuch earlier, it was only in 1996 that the blue laser wasdiscovered. Actually, the wavelength 405nm would correspondto the blueviolet part of the visible light, in the spectrum. Thisachievement is attributed to the efforts of Shuji Nakamura ofNichia Corporation, Japan. The device utilizes a GaN diode as itslaser source. The operating current is kept between 60mA and70mA for optimum performance.

For writing into the disc, the power of the laser used is about6mW. For reading from the disc, much lesser power is required,only about 0.7mW.The GaN source can give a power of about65mW. So, it is an ideal choice for the laser source to be usedwith the Bluray disc. Due to the much lower wavelengthinvolved, the amorphous mark size (bit size) is small, leading tohigher storage capacity on disc of the same size, about five tosix times the capacity of a DVD.

A blue laser operates in the blue range of the light spectrum,

ranging from about 405nm to 470nm. Most blue laser diodes

use indium gallium nitride as the material to create the laser

light, although the amount of indium included in the material

varies. (Some blue laser diodes use no indium.) Some

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manufacturers create blue LEDs (light-emitting diodes), which

create light in a manner similar to lasers with silicon carbide.

Blue laser beams have a smaller spot size and are more

precise than red laser beams, which lets data on blue laser

optical storage discs be stored more densely. The spot size of a

laser beam is one determining factor, along with the materials

in the optical disc and the way the laser is applie d to the disc,

in the size of the pits the laser makes on an optical disc. Laser

beams with larger spot sizes typically create larger pits than

those with smaller pit sizes. Blue lasers are desirable because

blue light has the shortest wavelength among visible light.

A blue laser operates at a shorter wavelength of about 405nmthan a red laser at about 650nm. A nanometer (nm) is one-

billionth of a meter, one-millionth of a millimeter, and one-thousandth of a micron. One inch is equal to about 25.4 millionnanometers. A human hair is about 50,000nm wide.

Blue Laser Development

Shiju Nakamura is credited with inventing the blue diode laser

and blue, green, and white LEDs. Nakamura was working at

Nichia Chemical Industries in Japan when he developed the

blue laser in 1995. Its a technology many large corporations

had been trying to develop for several years.

Nakamura had worked with LEDs and lasers for several years

before tackling blue lasers in the late 1980s. Because most

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research at the time focused on using zinc selenide as the laser

material, Nakamura decided to work with gallium nitride. He

spent two years perfecting a technique for growing high-quality

gallium nitride crystals, something other researchers had been

unable to achieve.

Finally, Nakamura had the materials necessary to create blue

LEDs, which he did in 1993. He followed with green LEDs and a

blue laser diode in the next few years. He says the biggest

commercial use for blue lasers should be DVD players.

Putting Blue Lasers to Work

Blue lasers could appear in a variety of business applications,

including high-density DVDs, laser printers, and lightingsituations.

HD DVDs: HD (high-definition) DVDs using blue laser light

could lead to five or six times the storage capacity possible

using red laser light on a DVD. Blue laser light could create HD

CDs, too.

Because blue lasers can increase the capacity of optical discs

by five-fold or more, they give manufacturers a few options for

their digital files. Manufacturers could choose to burn

additional data onto the disc while keeping the same digital

quality, potentially making CDs containing 50 to 75 songs.

Manufacturers also could choose to use blue laser to increase

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the quality level of the video or audio recording. Keep in mind

that nearly all DVDs using the MPEG-2 standard automatically

contain some compression of the video file, which allows the

file to fit on the disc. With an HD DVD, manufacturers could

choose to use no compression on the video file, which should

improve file quality.

Light bulbs: With green and red lasers already available,

development of a blue laser would be the final piece of the

laser puzzle among primary colors. By using all three colors of

lasers, a researcher could create a device that would mix the

laser light and create white light, which, at some point, could

replace the common light bulb. If you combine red, green, and

blue laser light, you can produce light with greater brilliance

and greater efficiency than currently is available with

fluorescent lights.

Creating LEDs in this manner can be of particular help in areas

where light bulbs are expensive and difficult to replace. An LED

can burn for several times as long as a light bulb for about one-

fourth the operating cost because most of the LEDs energy is

involved in creating light, rather than creating heat energy.

Traditional light bulbs create a lot of heat along with the light.

LEDs already are used in many traffic lights, where traditional

bulbs usually last less than one year, can be tough to see in

sunlight, and fail suddenly. LEDs in a traffic light should last at

least five years, remain highly visible in sunlight, and gradually

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fade in intensity rather than failing suddenly.

Medicine: Scientists already are experimenting with blue

lasers in discovering certain types of cancer. Using an

endoscope, researchers have had some success finding tumors

using a blue laser light inside the patients stomach and

intestinal tract.

Printing: Laser printers using blue laser light would be

smaller and more precise than todays laser printers, which usered laser light. Because of blue laser lights smaller

wavelength, the laser mechanism inside a printer that uses

blue laser light could be smaller, leading to smaller printers.

Print resolution using blue lasers would be at least double that

of todays top laser printers, too; some researchers estimate

resolution as sharp as 2,400dpi in a blue laser printer. Bluelaser could play a role in full-color scanners and fax machines,

too.

Security: After the terrorist attacks of Sept. 11, fears have

increased over additional attacks using biological or chemical

weapons. However, blue laser light causes some chemical andbiological agents to give off light, even though those agents

are invisible to the naked eye, which might let security

screening personnel spot a biological agent during a routine

search or as the agent comes through customs.

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3.Optical Data Storage for Digital Video

3.1 Introduction

Optical data storage is commercially successful in the form ofCompact Discs (CDs) for audio and software distribution andDigital Versatile Discs (DVDs) for video distribution. CDs and

DVDs look very similar because the fundamental opticaltechnology for both devices is the same. This similarity is alsotrue for the next generation of optical data storage, which maybe used for digital home theater recording and HDTVdistribution. However, CDs, DVDs and next generation productsare different in terms of specific optical components in thedrive, in how data are managed and in details of the diskstructure used to store the information. These differences allowa larger volume of data to be recorded on each successive

generation. Larger data volumes translate into higher qualityvideo and longer playing time.

3.2 Parameters for HD Video Storage withOptical Disks

Optical Parameters Disk Structure Parameters Data Management Parameters

Optical parameters include laser wavelength, objective lensnumerical aperture, protective layer thickness and free workingdistance. Data management parameters include data rate,video format, HDTV play time and bitrate scheme. Diskstructure parameters are user data capacity, minimum channel

bit length and tracktotrack spacing.

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3.2.1Optical parameter

Digital information is stored on optical disks in the form ofarrangements of data marks in spiral tracks.

The process for exposing data marks on a recordable opticaldisk is shown in Fig. 1, where an input stream of digitalinformation is converted with an encoder and modulator into adrive signal for a laser source. The laser source emits anintense light beam that is directed and focused onto thesurface by the objective lens. As the surface moves under the

scanning spot, energy from the intense scan spot is absorbed,and a small, localized region heats up. The surface, under theinfluence of heat

beyond a critical writing threshold, changes its reflectiveproperties.Modulation of the intense light beam is synchronous with the

drive signal, so

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a circular track of data marks is formed as the surface rotates.The scan spot ismoved slightly as the surface rotates to allow another track tobe written on

new media during the next revolution.

Data marks on prerecorded disks are fabricated by first makinga master disk with the appropriate datamark pattern. Mastersfor prerecorded CDs and DVDs are often exposed in a similarmanner to exposing data marks on recordable optical disks,except that the lightsensitive layer is designed to produce pitsin the master that serve as data marks in the replicas.

Inexpensive replicas of the master are made with Injectionmolding equipment.Readout of data marks on the disk is illustrated in Fig.2, wherethe laser is used at a constant output power level that does notheat the data surface beyond its thermal writing threshold. Thelaser beam is directed through a beam splitter into theobjective lens, where the beam is focused onto the surface. Asthe data marks to be read pass under the scan spot, thereflected light is modulated. Modulated light is collected by

illumination optics and directed by the beam splitter to servoand data optics, which converge the light onto detectors. Thedetectors change light modulation into current modulation thatis amplified and decoded to

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Fig 2

produce the output data stream. A fundamental limitation to

the number of

data marks per unit area is due to the size of the focused laserbeam thatilluminates the surface. Small laser spots are required to recordand read outsmall data marks. More data marks per unit area translate intohighercapacity disks, so evolution of optical data storage is toward

smaller spotsizes.

Figure 3 shows a detailed picture of the laser irradianceapproaching the surface, where irradiance is defined as thelaser power per unit area. Ideally, maximum irradiance islocated at the recording material, along with the smallest spotsize s. As the distance increases away from the ideal focus, thespot size increases and the peak irradiance decreases. A

defocus distance z of only a few micrometers dramaticallyreduces peak irradiance and increases spot size. An

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approximate formula used to estimate the ideal spot size atbest focus is s = /(sin ), where is the marginal ray angle ofthe illumination optics, as shown in Fig. 1. Spot size s is the fullwidth of the irradiance distribution at the 1/e2 (13.5%)

irradiance level relative to the peak. The value of sin q is oftencalled the numerical aperture or NA of the optical system.

Fig 3

Instead of focusing directly on the recording surface, optical

disks focus through a protective layer, as shown in Fig.4 for asimple CDROM. The protective layer prevents dust and othercontamination from directly obstructing the laser spot at thedata marks. Instead, the outoffocuscontamination only partially obscures the laser focus cone, anddata canusually be recovered reliably. If the protective layer isscratched or damaged,it can be cleaned or buffed.

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As the protective layer gets thinner, the error rate increases toan unacceptable threshold due to obscuration of the laserbeam. This sensitivity decreases as NA increases, due to thesmaller defocus range associated with these systems. In

addition, the free working distance separates the objective lensfrom the spinning disk. This separation protects the diskagainst accidental contact between the objective lens and thedisk.

In order to maximize disk capacity, the optical system useshigh NA and short wavelength. For maximum contaminationprotection, the protective layer should be as thick as possible.

However, the combination of thick protective layer and high NAis not easily accomplished. High NA systems are sensitive tochanges in substrate thickness and disk tilt. Manufacturingvariations create thickness no uniformities, which are usually

Fig 4

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a small percentage of the total disk thickness. Motorinstabilities induce tilt asthe disk spins. Energy from the central portion of the spot isredistributed to

concentric rings, which degrade the quality of the read outsignal. This Degrades the read out signal. Tilt causes coma,which is another form ofaberration effect, is called spherical aberration.

Sensitivity of the spot to degradation from thickness variationsand disk tilt is plotted in Fig. 5 as a function of total protectivelayer thickness for two values of NA. In order to limit these

effects,the substrate is made as thin as possible withoutsacrificing contamination protection.

The most conservative technology is the Video CD. Its thickprotective layer, relatively low NA and long laser wavelengthproduce a stable system that is not very sensitive toenvironmental factors like dust and scratches. The ideal spotsize is about 0.78/0.5 = 1.6 micrometers. Although the cover

layer is thick at 1.2 mm, the sensitivity to thickness

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variations and disk tilt is low because of the low NA. DVDtechnology uses ashorter wavelength laser, higher NA optics and a thinnerprotective layer. Thecombination of short wavelength and higher NA produce a spotsize of about1.1 micrometers. The protective layer had to be made thinner,because the

sensitivity to thickness variations and disk tilt is too highotherwise. DVDsare slightly more sensitive to dust and scratches than CDs. Thenet effect isnot great, because higher NA reduces the focal depth and DVDshave a morerobust error management strategy.

The Advanced Optical Disk and BluRay systems both use anew blue laser source that emits 0.405 micrometer light. The

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Advanced Optical Disk system uses the same protective layerthickness as a DVD, and it uses the same NA objective lens.Due to the short wavelength, the spot size for the AdvancedOptical Disk is about 0.62 micrometers.

Sensitivity to dust and scratches is about the same as a DVD,as well as thesensitivity to thickness variations and disk tilt. The BluRaysystem uses bothhigher NA and thinner cover layer. The spot size is 0.405/0.85= 0.48micrometers, which is the smallest spot size of all thetechnologies. However,because of the high NA, the protective layer had to be made

thin to limitsensitivity to thickness variations and disk tilt. Therefore, BluRay disks aresensitive to dust and scratches. The free working distance isnearly is same forall technologies except BluRay. BluRay systems utilize morecomplicatedlens systems due to the high NA, so working distance had to bereduced. The

integrity of this reduced working distance is not clear at thistime.

3.2.2 Disk Structure Parameters

The spot size created from the NA and wavelength parameters

is the most important factor to determine the tracktotrackspacing and the minimum channel bit length along the track.Several channel bits are encoded into each data mark. Thenumber of channel bits per data mark depends on themodulation scheme. The relatively large spot producesrelatively large data marks and correspondingly wide tracksand large channelbit lengths. Progressively smaller spot sizesenable smaller track spacing and shorter channel bit lengths.

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Fig 6

To the user, all generations of optical disks look very similar.They all are round disks that are approximately 120 mm indiameter, have a central mounting hole and are approximately1.2 mm thick. Through many years of experience with CDs, thisformat has proven effective and mechanically reliable.However, the manner in which data layers are arranged on thedisk depends on the technology used. For example, the CDuses a simple 1.2 mm thick substrate, as shown in Fig. 6A. Dataare recorded on only one side of the disk, through the clear 1.2

mm substrate, which also serves as the protective layer. DVDs,Warner HDDVDs and Advanced Optical Disks use the formatshown in Fig. 6B, where two 0.6 mm substrates are bondedtogether and the data are recorded on the bond side of eachsubstrate. DVDs also allow more two layers per side (A, B in Fig.6B), where the layers are separated by a thin adhesive spacer.

The two layers are fabricated before bonding at the same timeas the individual 0.6 mm substrates. Like the CD, data arerecorded and read through the clear substrates. It is likely that

the Warner HDDVD and Advanced Optical Disk

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will also take advantage of this multiplelayer concept. Apotential implementation of the BluRay disk is shown in Fig.6C, where the protective layers on each side are very thin at0.1 mm. In this case, data are recorded on the substrate, which

does not serve as the protective layer. Instead, a protectivelayer resin is spun on and hardened or a thin protective sheet isbonded on each side of the substrate. Because of the thinprotective layer, theBluRay disk must also be used with a cartridge.

The only optical disk technology that plans to use a Cartridge isthe BluRay system. The BluRay cartridge is necessary for

contamination Protection, but the working distance of around0.1 mm and protective layer thickness of 0.1 mm are largecompared to the contact recording.

The technology for making disks is very similar to existing DVDtechnology. Higherresolution mastering machines and finercontrol over the injection molding process should produce therequired changes without substantially retooling the industry.

The BluRay system requires the most changes of the three,including a blue laser, detector, and advanced objective lens.BluRay also requires new disk and cartridge manufacturingtechnology, which may be difficult to implement in a short timeframe.

3.2.3 Data Management Parameters

The logical organization of data on the disk and how those dataare used are considerations for data management. Datamanagement considerations have important implications in theapplication of optical disk technology to storage for HDTV. Forexample, simply using a more advanced error correctionscheme on DVDs allows a 30% higher disk capacity comparedto CDs. Data rate, video format, bitrate scheme and HDTV play

time are all data management issues.

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There is a basic difference in data management between CDsand DVDs. Since CDs were designed for audio, data are

managed in a manner similar to data management formagnetic tape. Long, contiguous files are used that are noteasily subdivided and written in a random access pattern.Efficient data retrieval is accomplished when these long filesare read out in a contiguous fashion. To be sure, CDs are muchmore efficient that magnetic tape for pseudorandom access,but the management philosophy is the same. On the otherhand, DVDs are more like magnetic hard disks, where the filestructure is designed to be used in randomaccess architecture.

That is, efficient recovery of variable length files is achieved. Inaddition, the Original error correction strategy for CDs wasdesigned for error concealment when listening to audio, whereDVDs utilize true error correction. Later generations of opticaldisks also follow the DVD model.

The randomaccess nature of DVDs allows very efficientmethods for data compression. For example, MPEG2 with

variable bit rate allows data to be read out from the disk asthey are required, rather than supplying data at a constantrate. Slowly moving scenes, like love scenes or conversations,require much less information per frame than a fastmoving carchase or explosion. In these fastmoving scenes, the maximumamount of information per scene is limited only by themaximum data rate of the player. For HDTV, acceptable picturequality is obtained by using MPEG2 with a maximum data rateof about 1325 Mbps for most scenes. During a slow scene, notas many files are accessed, and much less storage area on thedisk is used. This architecture leaves room on the disk for thedata associated with fastermoving scenes.

Fixedrate schemes, like magnetic tape, supply data at aconstant rate, no matter what the requirements of the scene.During fastmoving scenes, the data stream from the tapesupplies an adequate data rate. The tape speed and data ratefor these devices are set by the upper limit of the scenerequirements. Since the tape does not slow down during slower

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scenes, the data stream is padded at these times with uselessinformation that takes up valuable storage area on the tape.Overall, the randomaccess architecture of optical disks is amuch more efficient way to use the available storage area. That

is, optical disks do not require as many gigabytes of user datacapacity for an equivalent length and quality HDTVpresentation.

It is not practical to store HDTV on CDs and DVDs with MPEG2.For CDs, special multiplebeam readout or high velocity diskdives could produce the data rate, which is an advantage of thefixedbitrate scheme. However, the play time would be only afew minutes, at best. DVDs are not capable of the 13 Mbps

random data rate to support MPEG2. The Advanced OpticalDisk exhibits acceptable data rate and reasonable user datacapacity for up to two hours of HDTV per side compressed withvariable bitrate MPEG2. Bluray has slightly higher capacityand data rate. The twohour play time for HDTV with BluRay in

Table I is really a specification for realtime recording, which isnot easily compressed into an efficient variablerate scheme.BluRay should easily provide two hours or longer ofprerecorded HDTV per side compressed with MPEG2.

MPEG2 is a technique for compressing video data andreplaying the data associated with certain rules that aredefined in the MPEG2 specifications. The action of the opticaldisk system is not to compress data or interpret the videoinformation rules. Instead, the optical disk system only storesand retrieves data on command from the video operatingsystem. Therefore, as video operating systems and associatedcompression technology become more advanced, nofundamental changes are required to the optical disk system.MPEG4 technology is an advanced video compression schemethat utilizes advanced prefiltering and postfiltering, in additionto a rulebased algorithm. Estimated improvement incompression is a around a factor of three beyond MPEG2.

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4.Different Formats of Blueray Disc

BDROM : A read only format developed for prerecorded

content.

BDR : A write once format developed for PC storage.

BDRW : A rewritable format developed for PC storage.

BDRE : A rewritable format developed for HDTVrecording.

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5. Two Versions of Recording

5.1 One Time Recording

Making permanent changes to a disc. If we use BDR thematerial on the disc itself is changed forever. There is no way

to get the material back into its old state. The recordingmaterial is crystalline in nature. As scan spot falls on thesurface it changes to amorphous. We cannot change it back tocrystal state.

5.2 Record Many Times

If we use a BDRW the material on the disc itself changes, butcan be changed back again .We can do this as long as the

material doesnt get worn out. By heating up the crystals, theychange form. Now when we quickly cool them, they stay in thatform itself. That is the material is changed from crystal state toamorphous state.

Now, if we want to erase the BDRW, we have to make surethat we lose all the data. So we want to get rid of thatamorphous state. By heating up the material again, but this

time taking more time and less heat, the material gradually

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wants to take its old form again, and thus the information iserased. This state is called the crystalline state.

So, by very quickly heating it and very quickly cooling it, givethe crystal another state (Amorphous state) which thuscontains the data and by very quite slowly heating it andcooling it, we can give the crystals their old form back(crystalline state) which contains no more data. Its a constantchange of phases. And so it is called as phase changerecording.

Data is stored in the form of grooves, on an optical disc. Next tothe grooves, there are lands. Lands are the borders betweenthe grooves. Grooves and lands have a sinus form. This iscalled a wobbled groove. In the groove, pits are formed to storedata.

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6.Bluray Disc Structure

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The structure of the BD is as shown. The 0.1mm transparentcover layer is made of a spincoated UV resin. It is formed bysandwiching a transparent layer between a protective coatingand a bonding layer. This layer offers excellent birefringence.Beneath, there is a layer of Antis layer acts as a heat sink,

dissipating the excess heat during the write process. A spacerlayer made of ZnSSiO2 comes next. Then, the recording layermade of Ag, In, Sb, Te, Ge comes. Grooves are formed on thislayer for recording reflective layer of Ag alloy falls beneath andfinally a plastic substrate comes.

The key features of the technology are introduced as follows:

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Highly flat and smooth cover layer:

At the high speed recording rate involved, the linear velocity of

the disc reaches 20m/s or more and as a result accurate focuscontrol becomes difficult. Various experiments showed thatflatness and smoothness of the transparent cover layer have amarked influence on the focus control capability. This end isachieved by using the spin coating method for obtaining thetransparent cover layer. Thus stable record ability at highspeed recording is secured.

Phase change film for high speed recording:

The phase change film should have high re-crystallizationspeed to enable direct recording at the high linear velocitiesinvolved. A recording layer made of Ag, In, Sb, Te, Ge meetsthis purpose.

Super advanced rapid cooling structure:

The excess heat from the LASER irradiation causes distortion ofthe recorded mark edge. So, to diffuse the remaining excessheat, a transparent dielectric film of high thermal conductivity,for example, AlN is used.

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7.Basic Bluray Disc Characteristics

7.1 Large Recording Capacity

The Bluray disc enables the recording, rewriting and playbackof HD video unto 27 GB of data on a single sided single layer. Itis enough to put 2.5 hours of HDTV recording on it. It also canrecord over 13 hours of standard TV broadcasting using the

VHS/ standard definition picture quality.

7.2 High Speed

It has a data transfer rate of 36 Mbps. Because of this highspeed transfer rates it can also record the data in very little

time. In a perfect environment it would take about 2.5 hours tofill the entire BD with 27 GB of data. More than enough transfercapacity for real time recording and playback.

7.3 Resistant to Scratches and Fingerprints

The protective layer is hard enough to prevent accidentalabrasions and allows fingerprints to be removed by wiping thedisc with a tissue.

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8.Blu-ray Founders

The Blu-ray Disc is a technology platform that can store sound

and video while maintaining high quality and also access the

stored content in an easy-to-use way. This will be important in

the coming broadband era as content distribution becomes

increasingly diversified.

The following companies have jointly established the basic

specifications Bluray disc video recording format

1. Hitachi, Ltd

2. LG Electronics Inc.

3. Matsushita Electric Industrial Co. Ltd.

4. Mitsubishi Electric Corporation

5. Pioneer Corporation

6. Royal Philips Electronics

7. Samsung Electronics Co. Ltd.

8. Sharp Corporation

9. Sony Corporation

10.Thomson

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9.Characteristics of Ideal Communication

1. Speed: The blue laser technology will allow DVD

recording devices to record data at a speed of 36Mbps.

Developing companies such a TDK also stated that they will be

able to increase the recording speed up to 72Mbps and

144Mbps. Developing companies such as Toshiba and NEC

have been working on this technology and have already

developed the blue laser standard.

2. Reliability: Storage mediums used by blue laser

burners will provide high reliable backup at affordable prices.

Media types will provide a 50 year data life. They will also

employ a new dual shutter cartridge to minimize contamination

and protect valuable data stored on a disc.

3. Quality: Media storage devices using this technology will have a quality

similar to the quality of red laser storage devices. Optical discs have to be used

in a safe way. They should be in the case they come in or in the device using it.

This is to avoid scratching of the discs which can cause data on a disc to be

unreadable. Laser printers would me more precise than regular laser printers

that use red laser, because of the shorter wavelength that blue laser has.

4. Ease of Use: DVD recording devices are very simple touse. Even children can use them. There are no complexities to

the use of blue laser recording devices. They are used just like

any regular red laser DVD recording device. An easy to use

optical disc cartridge protects the optical disc's recording and

playback phase from dust and fingerprints.

5. Cost:The price of an optical disc recording device usingblue ray will start off with a high price tag around $1700. Just

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like any computer related devices that are new the price will

decrease as time passes. It has a high storage capacity which

is up to 60 GB on a dual sided DVD.

6. Safety and Security: Blue laser light helps in

detecting some chemical and biological weapons

because it causes them to give off light. So it could be

used in airports and other places that have security

screening to detect such a weapon.

10. How does Blu-ray disc work?

History of Technology

The challenge to write more information on disk Shiju

Nakamura is credited with inventing the blue diode laser and

blue, green, and white LEDs.

Nakamura was working at Nichia Chemical Industries in Japan

when he developed the blue laser in 1995.

Description of how this technology works

Blue lasers have a wavelength of 405 nanometers, shorter than

that of red lasers, which have a wavelength of around 650

nanometers and are used for reading and writing DVD and CD

discs. The shorter wavelength means that the laser can

register smaller dots on a disc and more data can be stored. As

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a result, blue laser technology has been adopted for the

development of next-generation optical discs.

1. Using double infrared frequency to create the wavelength for

blue light.

2. A blue laser operates in the blue range of the light spectrum,

ranging from about 405nm to 470nm.

3. Most blue laser diodes use indium, gallium nitride as the

material to create the laser light.

4. Blue laser beams have a smaller spot size and are more

precise than red laser beams, which lets data on blue laser

optical storage discs be stored more densely.

5. The spot size of a laser beam is one determining factor,

along with the materials in the optical disc and the way the

laser is applied to the disc, in the size of the pits the laser

makes on an optical disc.

6. Laser beams with larger spot sizes typically create larger

pits than those with smaller pit sizes.

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11.Comparisons

While current optical disc technologies such as CD, DVD, DVD-

R, DVD+R, DVD-RW and DVD+RW use a red laser to read and

write data, the new format uses a blue laser instead, hence the

name Blu-ray. The benefit of using a blue laser is that it has a

shorter wavelength (405 nanometer) than a red laser (650

nanometer), which means that it's possible to focus the laser

beam with even greater precision. This allows data to bepacked more tightly on the disc and makes it possible to fit

more data on the same size disc. Despite the different type of

lasers used, Blu-ray Disc Recorders will be made compatible

with current red-laser technologies and allow playback of CDs

and DVDs.The following diagram shows the comparison

between different storage Techn.

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12.Blu-ray Disc and HD-DVD

The HDDVD format, originally called AOD or Advanced OpticalDisc, is based on much of todays DVD principles and as aresult, suffers from many of its limitations. The format does notprovide as big of a technological step as Bluray Disc. Forexample, its prerecorded capacities are only 15 GB for a singlelayer disc, or 30 GB for a double layer disc. Bluray Disc

provides 67% more capacity per layer at 25 GB for a singlelayer and 50GB for a double layer disc.

Although the HDDVD format claims it keeps initial investmentsfor disc replicates and media manufacturers as low as possible,they still need to make substantial investments in modifyingtheir production equipment to create HDDVDs. But whatsmore important is that HDDVD can be seen as just a transitiontechnology, with a capacity not sufficient for the long term. It

might not offer enough space to hold a High Definition featurealong with bonus material in HD quality and additional materialthat can be revealed upon authorization via a network. Whentwo discs are needed, this will degrade the socalled costbenefit substantially. It is even possible that the HDDVDspecification will be followed up by a renewed version of thetechnology within a few years, requiring media manufacturersto upgrade their existing production lines again, and consumersto replace their existing playback/recording equipment. On the

other hand, the Bluray Disc format was designed to be a viabletechnology for a period of at least 10 to 15 years.

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Also on the application layer, the HDDVD format incorporatesmany compromises. As the capacity is not likely to be sufficientto encode a fulllength feature plus additional bonus materials

using the MPEG2 format, different and stronger encodingformats need to be used. Although Bluray Disc offers theseadvanced codec as well, the disc has such high capacity thatpublishers can still use the MPEG2 encoding format at bit ratesup to 54 Mbit/sec. As MPEG2 is the defacto standard used inalmost any industry involved in digital video (DVD, HDTV,digital broadcast), many authoring solutions are available.Chances are high that a full line MPEG2 encoding suite isalready available, which can be used with no or minor

adaptations to encode High Definition content for Bluray Disc.But perhaps the most important factor for the success of Bluray Disc is its overwhelming industrywide support. Almost allconsumer electronics companies in the world (combinedmarket share of about 90%) and the worlds two largestcomputer companies support the Bluray Disc format.

This ensures a large selection of Bluray Disc players,recorders, PC drives,Bluray Disc equipped PCs and blank media will become

available. A competing format will not have the manufacturingpower to penetrate the market in a level even approaching thatof Bluray Disc.

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13.Advantages

The main advantages of the Bluray disc are

More storage capacity on a disc of the same size

The data storage capacity on a Bluray disc is 27GB on a singlelayer and 54GB on dual layer, which is about five to six timesthe capacity of a DVD. It would mean about 2.5 hours of HDTVvideo and about 13 hours of SDTV video.

High data transfer rate.

The basic data transfer rate in Bluray disc is about 36Mbpswhich is about three times that of a DVD and thirty times thatof a CD.

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Available in different versions like ROM, R and RE

The BD is available in different versions like the ROM (writeonce), R (read only), RE (rewritable).

Backward compatible

The BD drives are designed to be backward compatible, i.e.CDs and DVDs work equally well with the BD drives.

Strong content protection

The features of the content protection system are Format Developed with Input from Motion Picture Studios.

Strong Copy Protection.

Renewability with Renewal Key Block and Device Key.

Enhanced Encryption Algorithm: AES 128 bit.

Physical Hook against Bit by Bit Encrypted Content Copy.

Titlebased Expandable Content Control File.

Production Process Control Works against Professional Piracy.

Public Key Based Authentication in PC Environment.

Compatible with analog and digital transmission

The BD fares well with analog as well as digital transmission. It

offers the only means to the recording and reproducing ofdigital HDTV video. Format for encoding analog signals also,

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called SESF (Self Encoded Stream Format) is also incorporatedinto the BD.

Higher disc life

In the case of ordinary discs, the disc life is less fir therewritable versions, as rewriting is done repeatedly to one areaof the disc most probably, the inner perimeter. This limits thedisc life. But, the BDFS(Bluray Disc File Structure is designedso as to avoid this problem, by using a system that uses freedisc spaces with equal frequency.

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14.The Blu-ray Impact

Blu-ray is expected to challenge DVD's run as the fastest

selling consumer-electronics item in history. If that happens,

the impact would be too big for the major players to discount.

For example, the number of films sold on DVD more than

doubled last year to over 37 million. In addition, almost 2.4

million DVD players were bought in the past year. As Blu-ray is

not compatible with DVD, its success could upset the applecartof many players. If the new format turns out to be much

popular, the demand for DVD players could come down

drastically. Not withstanding the challenge to DVD makers, the

new format is seen as a big step in the quest for systems

offering higher data storage. It is expected to open up new

opportunities for broadcasting industry. Recording of high-definition television videoan application in which more than

10GB of storage space is filled up with just one hour of video

will get a major boost. Conversely, the format could take

advantage of the spread of high-definition television. As Blu-ray

Disc uses MPEG-2 Transport Stream compression technology,

recording for digital broadcasting would become easier. Itsadoption will grow in the broadband era as it offers a

technology platform to manage stored content. But the real

action will begin when the companies involved develop

products that take full advantage of Blu-ray Disc's large

capacity and high-speed data transfer rate. As that happens,

Blu-ray will move beyond being a recording tool to a variety of

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applications. Adoption of Blu-ray Disc in PC data storage is

already being considered.

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15.Applications

High Definition Television Recording

High Definition Video Distribution

High Definition Camcorder Archiving

Mass Data Storage

Digital Asset Management and Professional Storage

The Bluray Disc format was designed to offer the bestperformance and features for a wide variety of applications.High Definition video distribution is one of the key features ofBluray Disc, but the formats versatile design and topoftheline specifications mean that it is suitable for a full range of

other purposes as well.

15.1 High Definition Television Recording

High Definition broadcasting is vastly expanding in the US andAsia. Consumers are increasingly making the switch to HDTV

sets to enjoy the best possible television experience. The Bluray Disc format offers consumers the ability to record their HighDefinition television broadcasts in their original quality for thefirst time, preserving the pure picture and audio level asoffered by the broadcaster. As such it will become the nextlevel in home entertainment, offering an unsurpassed userexperience. And since the Bluray Disc format incorporates thestrongest copy protection algorithms of any format or proposalto date, the format allows for recording of digital broadcasts

while meeting the content protection demands of the broadcastindustry.

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15.2 High Definition Video Distribution

Due to its enormous data capacity of 25 to 50 GB per (singlesided) disc, the Bluray Disc format can store High Definitionvideo in the highest possible quality. Because of the hugecapacity of the disc, there is no need to compromise on picturequality. Depending on the encoding method, there is room for

more than seven hours of the highest HD quality video. There iseven room for additional content such as special features andother bonus material to accompany the High Definition movie.

Furthermore, the Bluray Disc movie format greatly expands ontraditionalDVD capabilities, by incorporating many new interactivefeatures allowingcontent providers to offer an even more incredible experienceto consumers.An Internetconnection may even be used to unlock additionalmaterial that isstored on the disc, as there is enough room on the disc toinclude premiummaterial as well.

15.3 High Definition Camcorder Archiving

As the market penetration of High Definition TV sets continuesto grow, so does the demand of consumers to create their ownHD recordings. With the advent of the first HD camcorders,consumers can now for the first time record their own homemovies in a quality level unlike any before. As these

camcorders are tapebased, consumers cannot benefit from theconvenience and direct access features they are used to from

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the DVD players and recorders. Now, the Bluray Disc format,with its unprecedented storage capacity, allows for the HDvideo recorded with an HD camcorder to be seamlesslytransferred to a Bluray Disc. When the HD content is stored on

a Bluray Disc, it can be randomly accessed in a waycomparable to DVD. Furthermore, the Bluray Disc can beedited, enhanced with interactive menus for an even increaseduser experience and the disc can be safely stored for manyyears, without the risk of tape wear.

15.4 Mass Data Storage

In its day, CDR/RW meant a huge increase in storage capacitycompared to traditional storage media with its 650 MB. ThenDVD surpassed this amount by offering 4.7 to 8.5 GB ofstorage, an impressive 5 to 10 times increase. Now consumersdemand an even bigger storage capacity. The growing numberof broadband connections allowing consumers to download vastamounts of data, as well as the ever increasing audio, videoand photo capabilities of personal computers has lead to yetanother level in data storage requirements. In addition,commercial storage requirements are growing exponentiallydue to the proliferation of email and the migration to paperlessprocesses. The Bluray Disc format again offers 5 to 10 times asmuch capacity as traditional DVD resulting in 25 to 50 GB ofdata to be stored on a single rewritable or recordable disc. AsBluray Disc uses the same form factor as CD and DVD, thisallows for Bluray Disc drives that can still read and write to CDand DVD media as well.

15.5 Digital Asset Management and ProfessionalStorage

Due to its high capacity, low cost per GB and extremelyversatile ways of transferring data from one device to another

(because of Bluray Discs extremely wide adoption across theindustry), the format is optimized for Digital Asset Management

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and other professional applications that require vast amountsof storage space. Think of medical archives that may containnumerous diagnostic scans in the highest resolution, orcatalogs of audio visual assets that need to be instantly

retrieved in a random access manner, without the need torestore data from a storage carrier. One Bluray Disc mayreplace many backup tapes, CDs, DVDs or other less commonor proprietary storage media. And contrary to networksolutions, the discs can be physically stored in a differentlocation for backup and safekeeping.

16.Requirements

1) Blue laser

2) Detector

3) Advanced objective lens

4) New disk and cartridge manufacturing technologies

17.Challenges

High cost

The technology is not that popular and hence, the price of theBD recorders and players available in the market is very high.

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HD-DVD

The HDDVD (High Definition DVD) based on the AdvancedOptical System championed by Toshiba and NEC is the primaryrival to BD in the market. Though its data storage density islower, it has lower manufacturing costs also, which may provechallenging to the Bluray disc.

18.Future Developments

Efforts are progressing on many fronts to make the Bluraydiscs, players and recorders cheaper. On 15 April 2004 forinstance, Sony and Toppan Printing announced the successfuldevelopment of a Bluray Disc that is 51% (by mass) composedof paper, which could reduce production costs and improve itsenvironmental friendliness. The cost would come down as BDbecomes more and more popular.

TDK has been researching the hard coat technology that willprovide protection against fingerprints and scratches. Colloidalsilica dispersed UVcurable resin is being used for theresearches and results are encouraging.

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Figure shows the cross section of the disc being developed.

19. Conclusion

In conclusion the Blue-ray Disc is a technology platform that can store sound

and video while maintaining high quality and also access the stored content in

an easy-to-use way. Blue lasers have a shorter wavelength, which means the

laser beam can be focused onto a smaller area of the disc surface. In turn, this

means less real estate is needed to store one bit of data, and so more data can be

stored on a disc. This will be important in the coming broadband era as content

distribution becomes increasingly diversified. Companies involved in the

development will respectively make products that take full advantage of Blue-

ray Disc's large capacity and high-speed data transfer rate. They are also aiming

to further enhance the appeal of the new format through developing a largercapacity, such as over 30GB on a single sided single layer disc and over 50GB

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on a single sided double layer disc. Adoption of the Blue-ray Disc in a variety

of applications including PC data storage and high definition video software is

also being considered. There is a lot of talk about blue-laser-based systems

being focused around high-definition television, which has heavy data needs.

But Blue-ray Disc groups are also considering development of write-once and

read-only formats for use with PCs.

Prototype blue-laser-based optical disc systems have been around for more than

a year. However, one problem has hampered development of commercial

systems: cost. A sample blue-laser diode currently costs around $1000, making

consumer products based on the parts unrealistic. However, Nichia, the majorsource for blue lasers, is expected to begin commercial production this year and

the price of a blue-laser diode is expected to tumble once the company begins

turning them out in volume. The DVD forum may or may not invite the blue-

ray light into is era but the 27GB disc is not far off in practically disturbing the

DVD wave.

20. REFERENCES

Research Papers:

1) Wobble-address format of the blu-ray disc. By S.

Furumiya, S. Kobayashi, B. Stek, H. Ishibashi, T. Yamagami, K.

Schep: Presented at ISOM/ODS Hawaii, July 2002 .

2) Millipede- Nanotechnology Entering Data Storage, By

P. P. Vettiger, G. Cross, M. Despont, U. Drechsler, U. Drig, B.

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Gotsmann, W. Hberle, M. A. Lantz, H. E. Rothuizen, R. Stutz,

and G. K. Binnig:

3) 34 GB Multilevel-enabled Rewritable System using Blue

Laser and High NA Optics. By H. Hieslmair, J. Stinebaugh, T.

Wong, M. ONeill, M. Kuijper, G. Langereis: Published at

ISOM/ODS Hawai, July 2002.

Websites:

http://www.licensing.philips.com/

http://www.almaden.ibm.com/st/disciplines/storage/

http://www.bluraydisc.com/

http://www.blu-raytalk.com/

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http://www.licensing.philips.com/http://www.almaden.ibm.com/st/disciplines/storage/http://www.bluraydisc.com/http://www.blu-raytalk.com/http://www.almaden.ibm.com/st/disciplines/storage/http://www.bluraydisc.com/http://www.blu-raytalk.com/http://www.licensing.philips.com/


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22009086 Seminar Report on Blu Ray Disc by Sonal Singh

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