22009086 seminar report on blu ray disc by sonal singh(1)

8/4/2019 22009086 Seminar Report on Blu Ray Disc by Sonal Singh(1)

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SEMINAR REPORT BLU- RAY DISC

ELECTRONICS AND COMMUNICATION -1- GPTC NTA

ACKNOWLEDGEMENT

I would like to thank everyone who helped to see this seminar to completion. In

particular, I would like to thank my Guide Reji saroj 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. HISTORY OF BLU-RAY DISC1.1 FIRST GENERATION1.2 SECOND GENERATION

2. THIRD GENERATION3. OPTICAL DATA STORAGE FOR DIGITAL VIDEO

3.1 INTRODUCTION3.1.1 PARAMETERS FOR HD VIDEO STORAGE WITH

OPTICAL DISCS

3.1.2 DISK STRUCTURE PARAMETERS3.1.33.1.4 OPTICAL PARA METER

4. DATA MANAGEMENT PARAMETERS5. DIFFERENT FORMATS OF BD

5.1 TWO VERSIONS OF RECORDING5.2 ONE TIME RECORDING5.3 RECORD MANY TIMES5.4 BLU-RAY DISC STRUCTUREBLU-RAY DISC

CHARACTERISTICS

5.5 LARGE RECORDING CAPACITY5.6 HIGH SPEEDRESISTANCE TO SCRATCHES5.7 AND FINGERPRINTS

6. BLU-RAY FOUNDERS7. CHARACTERISTICS OF IDEAL COMMUNICATION8. HOW DOES BLU-RAY DISC WORK?9. COMPARISONS


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10.BLU-RAY DISC AND HD-DVD11.ADVANTAGES OF BD

11.1

THE BLU-RAY IMPACT11.2 APPLICATIONS11.3 HIGH DEFINITION TELEPHONE RECORDING11.4 HIGH DEFINITION VIDEO DISTRIBUTION11.5 HIGH DEFINITION CAMCORDER ARCHIVING11.6 MASS DATA STORAGE

12.DIGITAL ASSET MANAGEMENT ANDPROFESSIONAL STORAGE

13.REQUIREMENTS14.CHALLENGES15.FUTURE DEVELOPMENTS16.CONCLUSION


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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 laser 0.85. 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 isreduced to 0.32um, almost half of that of a regular DVD, achieving up to 27

GB high-density recording on a single 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 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


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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 theannouncement 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.

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


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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

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


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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 :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 andplayback 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 a significant improvement in audio

quality, its primary application, but its 650 MB storage capacity also meant a

giant leap in data storage and retrieval. For the first time, there was a universal

standard for prerecorded, recordable and rewritable media, offering the best

quality and features consumers could wish for themselves, at very low costs.

1.2 Second Generation

Although the CD was a very useful medium for the recording and distribution

of audio and some modest dataapplications, demand for a new medium

offering higher storage capacities rose 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 and recording.

Furthermore, the increased capacity accommodated more demanding data

applications. At the same time, the DVD spec used the same form factor as the


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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. History proved that a

significant five to ten time increase in storage capacity and the ability to playprevious generation formats are key elements for a new format to succeed. This

new format has arrived with the advent of Bluray Disc, the only format that

offers a considerable increase in storage capacity with its 25 to 50 GB data

capacity. This allows for the next big application of optical media: the

distribution and recording of High Definition video in the highest possible

quality. In fact, no other proposed format can offer the data capacity of

Bluray Disc, and no other format will allow for the same high video quality and

Interactive features to create the ultimate user experience. As with DVD, the

Blu-ray Disc format is based on the same, bare disc physical form factor,

allowing for compatibility with CD and DVD. The Bluray Disc specification

was officially announced in February 2002. Bluray Disc recorders were first

launched in Japan in 2003.

1982 First working CD player developed by Philips. Philips and Sony

developed CD standard12cm disk, 74 minutes on a single spiral

1983 First CD players sold

1985 CDROM introducednot popular at first. More powerful PCs lead

to demand for multimedia, image processing and larger applications. Growth

in sales brings prices down.


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1990s CDR and CDRW introducedbig success.

1996 DVD introduced

1999DVD becomes mainstream

2003 BD introduced

3. Optical Data Storage for Digital Video

3.1 Introduction

Optical data storage is commercially successful in the form of Compact Discs

(CDs) for audio and software distribution and Digital Versatile Discs (DVDs)

for video distribution. CDs and DVDs look very similar because the

fundamental optical technology for both devices is the same. This similarity is

also true for the next generation of optical data storage, which may be used for

digital home theater recording and HDTV distribution. However, CDs, DVDs

and next generation products are different in terms of specific optical

components in the drive, in how data are managed and in details of the disk

structure used to store the information. These differences allow a larger volume

of data to be recorded on each successive generation. Larger data volumes

translate into higher quality video and longer playing time.

3.2 Parameters for HD Video Storage with Optical Disks

Optical Parameters Disk Structure Parameters


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Data Management Parameters

Optical parameters include laser wavelength, objective lens numerical aperture,

protective layer thickness and free working distance. Data management

parameters include data rate, video format, HDTV play time and bitrate

scheme. Disk structure parameters are user data capacity, minimum channel bit

length and tracktotrack spacing.

3.2.1Optical parameter

Digital information is stored on optical disks in the form of arrangements of

data marks in spiral tracks.

The process for exposing data marks on a recordable optical disk is shown in

Fig. 1, where an input stream of digital information is converted with an

encoder and modulator into a drive signal for a laser source. The laser source

emits an intense light beam that is directed and focused onto the surface 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


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surface, under the influence of heat

beyond a critical writing threshold, changes its reflective properties.

Modulation of the intense light beam is synchronous with the drive signal, so

a circular track of data marks is formed as the surface rotates. The scan spot is

moved slightly as the surface rotates to allow another track to be written on

new media during the next revolution.

Data marks on prerecorded disks are fabricated by first making a master disk

with the appropriate datamark pattern. Masters for prerecorded CDs and DVDs

are often exposed in a similar manner to exposing data marks on recordable

optical disks, except that the lightsensitive layer is designed to produce pits in


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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, where the laser is usedat a constant output power level that does not heat the data surface beyond its

thermal writing threshold. The laser beam is directed through a beam splitter

into the objective lens, where the beam is focused onto the surface. As the data

marks to be read pass under the scan spot, the reflected light is modulated.

Modulated light is collected by illumination optics and directed by the beam

splitter to servo and data optics, which converge the light onto detectors. The

detectors change light modulation into current modulation that is amplified and

decoded to

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 laser beam that


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illuminates the surface. Small laser spots are required to record and read out

small data marks. More data marks per unit area translate into higher

capacity disks, so evolution of optical data storage is toward smaller spotsizes.

Figure 3 shows a detailed picture of the laser irradiance approaching the surface,

where irradiance is defined as the laser power per unit area. Ideally, maximum

irradiance is located at the recording material, along with the smallest spot size

s. As the distance increases away from the ideal focus, the spot size increases

and the peak irradiance decreases. A defocus distance z of only a few

micrometers dramatically reduces peak irradiance and increases spot size. An

approximate formula used to estimate the ideal spot size at best focus is s =

/(sin ), where is the marginal ray angle of the illumination optics, as shown

in Fig. 1. Spot size s is the full width of the irradiance distribution at the 1/e2

(13.5%) irradiance level relative to the peak. The value of sin q is often called

the numerical aperture or NA of the optical system.


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Fig 3

Instead of focusing directly on the recording surface, optical disks focus througha protective layer, as shown in Fig.4 for a simple CDROM. The protective

layer prevents dust and other contamination from directly obstructing the laser

spot at the data marks. Instead, the outoffocus

contamination only partially obscures the laser focus cone, and data can

usually be recovered reliably. If the protective layer is scratched or damaged,

it can be cleaned or buffed.

As the protective layer gets thinner, the error rate increases to an unacceptable

threshold due to obscuration of the laser beam. This sensitivity decreases as NA

increases, due to the smaller defocus range associated with these systems. In

addition, the free working distance separates the objective lens from the

spinning disk. This separation protects the disk against accidental contact

between the objective lens and the disk.


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In order to maximize disk capacity, the optical system uses high NA and shortwavelength. For maximum contamination protection, the protective layer should

be as thick as possible. However, the combination of thick protective layer and

high NA is not easily accomplished. High NA systems are sensitive to changes

in substrate thickness and disk tilt. Manufacturing variations create thickness no

uniformities, which are usually

Fig 4

a small percentage of the total disk thickness. Motor instabilities induce tilt as


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the disk spins. Energy from the central portion of the spot is redistributed to

concentric rings, which degrade the quality of the read out signal. 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 variations and disk tilt is

plotted in Fig. 5 as a function of total protective layer thickness for two values

of NA. In order to limit these effects,the substrate is made as thin as possible

without sacrificing contamination protection.

The most conservative technology is the Video CD. Its thick protective layer,

relatively low NA and long laser wavelength produce a stable system that is not

very sensitive to environmental factors like dust and scratches. The ideal spot

size 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. DVD technology uses a

shorter wavelength laser, higher NA optics and a thinner protective layer. The

combination of short wavelength and higher NA produce a spot size of about

1.1 micrometers. The protective layer had to be made thinner, because the

sensitivity to thickness variations and disk tilt is too high otherwise. DVDs

are slightly more sensitive to dust and scratches than CDs. The net effect is

not great, because higher NA reduces the focal depth and DVDs have a more

robust error management strategy.

The Advanced Optical Disk and BluRay systems both use a new blue laser

source that emits 0.405 micrometer light. The Advanced Optical Disk system


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uses the same protective layer thickness as a DVD, and it uses the same NA

objective lens. Due to the short wavelength, the spot size for the Advanced

Optical Disk is about 0.62 micrometers.Sensitivity to dust and scratches is about the same as a DVD, as well as the

sensitivity to thickness variations and disk tilt. The BluRay system uses both

higher NA and thinner cover layer. The spot size is 0.405/0.85 = 0.48

micrometers, which is the smallest spot size of all the technologies. However,

because of the high NA, the protective layer had to be made thin to limit

sensitivity to thickness variations and disk tilt. Therefore, BluRay disks are

sensitive to dust and scratches. The free working distance is nearly is same for

all technologies except BluRay. BluRay systems utilize more complicated

lens systems due to the high NA, so working distance had to be reduced. The

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

3.2.2 Disk Structure Parameters

The spot size created from the NA and wavelength parameters is the most

important factor to determine the tracktotrack spacing and the minimum

channel bit length along the track. Several channel bits are encoded into each

data mark. The number of channel bits per data mark depends on the

modulation scheme. The relatively large spot produces relatively large data

marks and correspondingly wide tracks and large channelbit lengths.

Progressively smaller spot sizes enable 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 in diameter, have a central mounting hole

and are approximately 1.2 mm thick. Through many years of experience with

CDs, this format has proven effective and mechanically reliable. However, the

manner in which data layers are arranged on the disk depends on the technology

used. For example, the CD uses a simple 1.2 mm thick substrate, as shown inFig. 6A. Data are 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 format shown in Fig. 6B, where

two 0.6 mm substrates are bonded together and the data are recorded on the

bond side of each substrate. 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 time as the individual 0.6 mm


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substrates. Like the CD, data are recorded and read through the clear substrates.

It is likely that the Warner HDDVD and Advanced Optical Disk

will also take advantage of this multiple

layer concept. A potentialimplementation of the BluRay disk is shown in Fig. 6C, where the protective

layers on each side are very thin at 0.1 mm. In this case, data are recorded on

the substrate, which does not serve as the protective layer. Instead, a protective

layer resin is spun on and hardened or a thin protective sheet is

bonded on each side of the substrate. Because of the thin protective layer, the

Blu

Ray disk must also be used with a cartridge.

The only optical disk technology that plans to use a Cartridge is the BluRay

system. The BluRay cartridge is necessary for contamination Protection, but

the working distance of around 0.1 mm and protective layer thickness of 0.1

mm are large compared to the contact recording.

The technology for making disks is very similar to existing DVD technology.

Higherresolution mastering machines and finer control over the injection

molding process should produce the required 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 manufacturing technology, which may be

difficult to implement in a short time frame.

3.2.3 Data Management Parameters


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The logical organization of data on the disk and how those data are used are

considerations for data management. Data management considerations haveimportant implications in the application of optical disk technology to storage

for HDTV. For example, simply using a more advanced error correction scheme

on DVDs allows a 30% higher disk capacity compared to CDs. Data rate, video

format, bit rate scheme and HDTV play time are all data management issues.

There is a basic difference in data management between CDs and DVDs. Since

CDs were designed for audio, data are managed in a manner similar to data

management for magnetic tape. Long, contiguous files are used that are not

easily subdivided and written in a random access pattern. Efficient data retrieval

is accomplished when these long files are read out in a contiguous fashion. To

be sure, CDs are much more efficient that magnetic tape for pseudorandom

access, but the management philosophy is the same. On the other hand, DVDs

are more like magnetic hard disks, where the file structure is designed to be

used in random access architecture. That is, efficient recovery of variable

length files is achieved. In addition, the Original error correction strategy for

CDs was designed for error concealment when listening to audio, where DVDs

utilize true error correction. Later generations of optical disks also follow the

DVD model.

The random access nature of DVDs allows very efficient methods for data

compression. For example, MPEG 2 with variable bit rate allows data to be

read out from the disk as they are required, rather than supplying data at a

constant rate. Slowly moving scenes, like love scenes or conversations, require


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much less information per frame than a fast moving car chase or explosion. In

these fast moving scenes, the maximum amount of information per scene is

limited only by the maximum data rate of the player. For HDTV, acceptablepicture quality is obtained by using MPEG 2 with a maximum data rate of

about 13 25 Mbps for most scenes. During a slow scene, not as many files are

accessed, and much less storage area on the disk is used. This architecture

leaves room on the disk for the data associated with faster moving scenes.

Fixed rate schemes, like magnetic tape, supply data at a constant rate, no

matter what the requirements of the scene. During fast moving scenes, the data

stream from the tape supplies an adequate data rate. The tape speed and data

rate for these devices are set by the upper limit of the scene requirements. Since

the tape does not slow down during slower scenes, the data stream is padded

at these times with useless information that takes up valuable storage area on

the tape. Overall, the random access architecture of optical disks is a much

more efficient way to use the available storage area. That is, optical disks do not

require as many gigabytes of user data capacity for an equivalent length and

quality HDTV presentation.

It is not practical to store HDTV on CDs and DVDs with MPEG 2. For CDs,

special multiple

beam readout or high velocity disk dives could produce the

data rate, which is an advantage of the fixed bit rate scheme. However, the

play time would be only a few minutes, at best. DVDs are not capable of the 13

Mbps random data rate to support MPEG 2. The Advanced Optical Disk

exhibits acceptable data rate and reasonable user data capacity for up to two

hours of HDTV per side compressed with variable bitrate MPEG 2. Blu ray

has slightly higher capacity and data rate. The two

hour play time for HDTV


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with Blu Ray in Table I is really a specification for realtime recording, which

is not easily compressed into an efficient variable rate scheme. Blu Ray

should easily provide two hours or longer of prerecorded HDTV per sidecompressed with MPEG 2.

MPEG 2 is a technique for compressing video data and replaying the data

associated with certain rules that are defined in the MPEG 2 specifications.

The action of the optical disk system is not to compress data or interpret the

video information rules. Instead, the optical disk system only stores and

retrieves data on command from the video operating system. Therefore, as video

operating systems and associated compression technology become more

advanced, no fundamental changes are required to the optical disk system.

MPEG 4 technology is an advanced video compression scheme that utilizes

advanced pre filtering and post filtering, in addition to a rule based

algorithm. Estimated improvement in compression is a around a factor of three

beyond MPEG 2.


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4.Different Formats of Blue ray Disc

BD ROM : A read only format developed for prerecorded

content.

BD R : A write once format developed for PC storage.

BD

RW : A rewritable format developed for PC storage.

BD RE : A rewritable format developed for HDTV

recording.


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5. Two Versions of Recording

5.1 One Time Recording

Making permanent changes to a disc. If we use BD R the material on the disc

itself is changed forever. There is no way to get the material back into its old

state. The recording material is crystalline in nature. As scan spot falls on the

surface it changes to amorphous. We cannot change it back to crystal state.

5.2 Record Many Times

If we use a BD RW the material on the disc itself changes, but can be changed

back again .We can do this as long as the material doesnt get worn out. By

heating up the crystals, they change form. Now when we quickly cool them,

they stay in that form itself. That is the material is changed from crystal state to

amorphous state.

Now, if we want to erase the BD RW, we have to make sure that we lose all

the data. So we want to get rid of that amorphous state. By heating up the

material again, but this time taking more time and less heat, the material

gradually wants to take its old form again, and thus the information is erased.

This state is called the crystalline state.

So, by very quickly heating it and very quickly cooling it, give the crystal

another state (Amorphous state) which thus contains the data and by very quite

slowly heating it and cooling it, we can give the crystals their old form back


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(crystalline state) which contains no more data. Its a constant change of phases.

And so it is called as phase change recording.

Data is stored in the form of grooves, on an optical disc. Next to the grooves,

there are lands. Lands are the borders between the grooves. Grooves and lands

have a sinus form. This is called a wobbled groove. In the groove, pits are

formed to store data.

6.Blu ray Disc Structure


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The structure of the BD is as shown. The 0.1mm transparent cover layer is made

of a spin coated UV resin. It is formed by sandwiching a transparent layer

between a protective coating and 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 spacer layer made of

ZnS SiO2 comes next. Then, the recording layer made of Ag, In, Sb, Te, Ge

comes. Grooves are formed on this layer for recording reflective layer of Ag

alloy falls beneath and finally a plastic substrate comes.


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The key features of the technology are introduced as follows:

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 focus control becomes difficult. Various

experiments showed that flatness and smoothness of the transparent cover layer

have a marked influence on the focus control capability. This end is achieved by

using the spin coating method for obtaining the transparent cover layer. Thus

stable record ability at high speed recording is secured.

Phase change film for high speed recording:

The phase change film should have high re-crystallization speed to enable direct

recording at the high linear velocities involved. A recording layer made of Ag,

In, Sb, Te, Ge meets this purpose.

Super advanced rapid cooling structure:

The excess heat from the LASER irradiation causes distortion of the recorded

mark edge. So, to diffuse the remaining excess heat, a transparent di electric

film of high thermal conductivity, for example, AlN is used.


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7.Basic Blu ray Disc Characteristics

7.1 Large Recording Capacity

The Blu ray disc enables the recording, rewriting and playback of HD video

unto 27 GB of data on a single sided single layer. It is enough to put 2.5 hours

of HDTV recording on it. It also can record 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 high speed transfer rates it

can also record the data in very little time. In a perfect environment it would

take about 2.5 hours to fill the entire BD with 27 GB of data. More than enough

transfer capacity for real time recording and playback.

7.3 Resistant to Scratches and Fingerprints

The protective layer is hard enough to prevent accidental abrasions and allows

fingerprints to be removed by wiping the disc 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

Blu ray disc video recording format

1. Hitachi, Ltd

2. LG Electronics Inc.

3. Matsushita Electric Industrial Co. Ltd.

4. Mitsubishi Electric Corporation

5. Pioneer Corporation


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6. Royal Philips Electronics

7. Samsung Electronics Co. Ltd.

8. Sharp Corporation

9. Sony Corporation

10.Thomson

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 alsostated 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


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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 to use. 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 using blue ray will startoff with a high price tag around $1700. Just 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 andbiological 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?


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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 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.


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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 be packed more tightly on the disc andmakes 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 HD DVD format, originally called AOD or Advanced Optical Disc, is

based on much of todays DVD principles and as a result, suffers from many of

its limitations. The format does not provide as big of a technological step as

Blu ray Disc. For example, its pre recorded capacities are only 15 GB for a

single layer disc, or 30 GB for a double layer disc. Blu ray Disc provides 67%

more capacity per layer at 25 GB for a single layer and 50GB for a double layer

disc.

Although the HD DVD format claims it keeps initial investments for disc

replicates and media manufacturers as low as possible, they still need to make

substantial investments in modifying their production equipment to create

HD DVDs. But whats more important is that HD DVD can be seen as just a

transition technology, with a capacity not sufficient for the long term. It might

not offer enough space to hold a High Definition feature along with bonus

material in HD quality and additional material that can be revealed upon

authorization via a network. When two discs are needed, this will degrade the

so

called cost benefit substantially. It is even possible that the HD

DVD


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specification will be followed up by a renewed version of the technology within

a few years, requiring media manufacturers to upgrade their existing production

lines again, and consumers to replace their existing playback/recordingequipment. On the other hand, the Blu ray Disc format was designed to be a

viable technology for a period of at least 10 to 15 years.

Also on the application layer, the HD DVD format incorporates many

compromises. As the capacity is not likely to be sufficient to encode a

full length feature plus additional bonus materials using the MPEG 2 format,

different and stronger encoding formats need to be used. Although Blu ray

Disc offers these advanced codec as well, the disc has such high capacity that

publishers can still use the MPEG 2 encoding format at bit rates up to 54

Mbit/sec. As MPEG 2 is the de facto standard used in almost any industry

involved in digital video (DVD, HDTV, digital broadcast), many authoring

solutions are available. Chances are high that a full line MPEG 2 encoding

suite is already available, which can be used with no or minor adaptations to

encode High Definition content for Blu ray Disc. But perhaps the most

important factor for the success of Blu ray Disc is its overwhelming

industry wide support. Almost all consumer electronics companies in the

world (combined market share of about 90%) and the worlds two largest

computer companies support the Blu ray Disc format.

This ensures a large selection of Blu

ray Disc players, recorders, PC drives,

Blu ray Disc equipped PCs and blank media will become available. A

competing format will not have the manufacturing power to penetrate the

market in a level even approaching that of Blu ray Disc.


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13.Advantages

The main advantages of the Blu ray disc are

More storage capacity on a disc of the same size

The data storage capacity on a Blu ray disc is 27GB on a single layer and

54GB on dual layer, which is about five to six times the capacity of a DVD. It

would mean about 2.5 hours of HDTV video and about 13 hours of SDTV

video.

High data transfer rate.

The basic data transfer rate in Blu ray disc is about 36Mbps which is about

three times that of a DVD and thirty times that of a CD.

Available in different versions like ROM, R and RE

The BD is available in different versions like the ROM (write once), R (read

only), RE (rewritable).

Backward compatible


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The BD drives are designed to be backward compatible, i.e. CDs and DVDs

work equally well with the BD drives.

Strong content protectionThe 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 Hookagainst Bit by Bit Encrypted Content Copy.

Title based Expandable Content Control File.

Production Process Control Works against Professional Piracy.

Public Key Based Authentication in PC Environment.

Compatible with analog and digital transmission


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The BD fares well with analog as well as digital transmission. It offers the only

means to the recording and reproducing of digital HDTV video. Format for

encoding analog signals also, called SESF (Self Encoded Stream Format) is alsoincorporated into the BD.

Higher disc life

In the case of ordinary discs, the disc life is less fir the rewritable versions, as

re writing is done repeatedly to one area of the disc most probably, the inner

perimeter. This limits the disc life. But, the BDFS(Blu ray Disc File Structure

is designed so as to avoid this problem, by using a system that uses free disc

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 applecart of 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 videowill 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. Its

adoption 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 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 Blu

ray Disc format was designed to offer the best performance and

features for a wide variety of applications. High Definition video distribution is

one of the key features of Blu ray Disc, but the formats versatile design and

top of the line 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 and Asia.

Consumers are increasingly making the switch to HDTV sets to enjoy the best

possible television experience. The Blu

ray Disc format offers consumers the


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ability to record their High Definition television broadcasts in their original

quality for the first time, preserving the pure picture and audio level as offered

by the broadcaster. As such it will become the next level in home entertainment,offering an unsurpassed user experience. And since the Blu ray Disc format

incorporates the strongest copy protection algorithms of any format or proposal

to date, the format allows for recording of digital broadcasts while meeting the

content protection demands of the broadcast industry.

15.2 High Definition Video Distribution

Due to its enormous data capacity of 25 to 50 GB per (single sided) disc, the

Blu ray Disc format can store High Definition video in the highest possible

quality. Because of the huge capacity of the disc, there is no need to

compromise on picture quality. Depending on the encoding method, there is

room for more than seven hours of the highest HD quality video. There is even

room for additional content such as special features and other bonus material to

accompany the High Definition movie.

Furthermore, the Blu ray Disc movie format greatly expands on traditional

DVD capabilities, by incorporating many new interactive features allowing

content providers to offer an even more incredible experience to consumers.

An Internet connection may even be used to unlock additional material that is

stored on the disc, as there is enough room on the disc to include premium


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material as well.

15.3 High Definition Camcorder Archiving

As the market penetration of High Definition TV sets continues to grow, so

does the demand of consumers to create their own HD recordings. With the

advent of the first HD camcorders, consumers can now for the first time record

their own home movies in a quality level unlike any before. As these

camcorders are tape based, consumers cannot benefit from the convenience

and direct access features they are used to from the DVD players and recorders.

Now, the Blu ray Disc format, with its unprecedented storage capacity, allows

for the HD video recorded with an HD camcorder to be seamlessly transferred

to a Blu ray Disc. When the HD content is stored on a Blu ray Disc, it can be

randomly accessed in a way comparable to DVD. Furthermore, the Blu ray

Disc can be edited, enhanced with interactive menus for an even increased user

experience and the disc can be safely stored for many years, without the risk of

tape wear.

15.4 Mass Data Storage

In its day, CD R/RW meant a huge increase in storage capacity compared to

traditional storage media with its 650 MB. Then DVD surpassed this amount by

offering 4.7 to 8.5 GB of storage, an impressive 5 to 10 times increase. Now

consumers demand an even bigger storage capacity. The growing number of


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broadband connections allowing consumers to download vast amounts of data,

as well as the ever increasing audio, video and photo capabilities of personal

computers has lead to yet another level in data storage requirements. Inaddition, commercial storage requirements are growing exponentially due to the

proliferation of e mail and the migration to paperless processes. The Blu ray

Disc format again offers 5 to 10 times as much capacity as traditional DVD

resulting in 25 to 50 GB of data to be stored on a single rewritable or recordable

disc. As Blu ray Disc uses the same form factor as CD and DVD, this allows

for Blu ray Disc drives that can still read and write to CD and DVD media as

well.

15.5 Digital Asset Management and Professional Storage

Due to its high capacity, low cost per GB and extremely versatile ways of

transferring data from one device to another (because of Blu ray Discs

extremely wide adoption across the industry), the format is optimized for

Digital Asset Management and other professional applications that require vast

amounts of storage space. Think of medical archives that may contain numerous

diagnostic scans in the highest resolution, or catalogs 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 Blu ray Disc may replace many

backup tapes, CDs, DVDs or other less common or proprietary storage media.

And contrary to network solutions, the discs can be physically stored in a

different location for backup and safekeeping.


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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 the BD recorders and

players available in the market is very high.

HD-DVD


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The HD DVD (High Definition DVD) based on the Advanced Optical System

championed by Toshiba and NEC is the primary rival to BD in the market.Though its data storage density is lower, it has lower manufacturing costs also,

which may prove challenging to the Blu ray disc.

18.Future Developments

Efforts are progressing on many fronts to make the Blu ray discs, players and

recorders cheaper. On 15 April 2004 for instance, Sony and Toppan Printing

announced the successful development of a Bluray Disc that is 51% (by mass)

composed of paper, which could reduce production costs and improve its

environmental friendliness. The cost would come down as BD becomes more

and more popular.

TDK has been researching the hard coat technology that will provide protection

against fingerprints and scratches. Colloidal silica dispersed UV curable resin

is being used for the researches 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-


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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 50GBon 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 major

source 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.

22009086 seminar report on blu ray disc by sonal singh(1)

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