48652979 Seminar Report on Blu Ray Disc

8/2/2019 48652979 Seminar Report on Blu Ray Disc

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SEMINAR REPORT

ON

BLU-RAY DISC

DEPARTMENT OF ELECTRONICS & COMPUTERS

SREENIDHI INSTITUTE OF SCIENCE AND TECHNOLOGY

HYDERABAD

SUBMITTED BY:-

D Pavan Kumar

ECM 4th

year

07311A1965


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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 copyrightprotection inside the recorded streams.

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

with a nice color.


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INDEX

INTRODUCTION..5

1.

HISTORY OF BLU-RAY DISC.91.1 FIRST GENERATION...91.2 SECOND GENERATION91.3 THIRD GENERATION.9

2. GLOSSARY OF TERMS2.1 HDTV.112.2 MPEG112.3 GIGABYTE..122.4 LAYER122.5 SDTV..132.6 NUMERICALAPERTURE.132.7 BLUE LASER14

3. OPTICAL DATA STORAGE FOR DIGITAL VIDEO3.1 INTRODUCTION193.2 PARAMETERS FOR HD VIDEO STORAGE WITH OPTICAL

DISCS.193.2.1 OPTICAL PARA METER.193.2.2 DISK STRUCTURE PARAMETERS253.2.3 DATA MANAGEMENT PARAMETERS.27

4. DIFFERENT FORMATS OF BD295. TWO VERSIONS OF RECORDING30

5.1 ONE TIME RECORDING..305.2 RECORD MANY TIMES30

6. BLU-RAY DISC STRUCTURE.317. BLU-RAY DISC CHARACTERISTICS...34

7.1 LARGE RECORDING CAPACITY.347.2 HIGH SPEED347.3 RESISTANCE TO SCRATCHES AND

FINGERPRINTS..34

8. BLU-RAY FOUNDERS...359. CHARACTERISTICS OF IDEAL COMMUNICATION3610.HOW DOES BLU-RAY DISC WORK? ..37


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11.COMPARISONS3912.BLU-RAY DISC AND HD-DVD4013.ADVANTAGES OF BD4114.APPLICATIONS .43

14.1 HIGH DEFINITION TELEPHONE RECORDING4314.2 HIGH DEFINITION VIDEO DISTRIBUTION4414.3 HIGH DEFINITION CAMCORDER ARCHIVING4414.4 MASS DATA STORAGE4514.5 DIGITAL ASSET MANAGEMENT AND

PROFESSIONAL STORAGE ...45

15.REQUIREMENTS 4616.CHALLENGES ..4617.FUTURE DEVELOPMENTS..4718.CONCLUSION.4819.REFERENCES 49


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Introduction

Tokyo Japan : 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 is

reduced 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.


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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.

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

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.


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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 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 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 bestquality 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 distributionof 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

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 play

previous 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


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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 andInteractive 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 standard 12cm disk, 74 minutes on a single spiral

1983 First CD players sold

1985 CDROM introduced not popular at first. More powerful PCs lead

to demand for multimedia, image processing and larger applications. 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 can now be recorded

to standard mini DV cassettes. Consumer high definition cameras are

becoming available but this is currently an expensive, niche market. It is also

possible to capture video using inexpensive webcams. These normally connect

to a computer via USB. While they are much cheaper than DV cameras,

webcams offer lower quality and less flexibility for editing purposes, as they donot capture video in DV format. Digital video is available on many portable

devices from digital stills cameras to mobile phones. This is contributing to the

emergence of digital video as a standard technology used and shared by

people on a daily basis.

2.2 MPEG

MPEG, the Moving Picture Experts Group, overseen by the International

Standards Organization (ISO), develops standards for digital video and digital

audio compression. MPEG1 with a default resolution of 352x240 was designed

specifically for VideoCD and CDmedia and is often used in CDROMs.

MPEG1 audio layer3 (MP3) compression evolved from early MPEG work.

MPEG1 is an established, medium quality format (similar to VHS) supported byall players and platforms. Although not the best quality, it will work well on

older specification machines.

MPEG2 compression (as used for DVD movies anddigital television settop

boxes) is an excellent format for distributing video, as it offers high quality and

smaller file sizes than DV. Due to the way it compresses video

MPEG2encoded footage is more problematic to edit than DV footage. Despite

this, MPEG2 is becoming more common as a capture format. MPEG 2 uses

variable bit rates allowing frames to be encoded with more or less data


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depending on their contents. Most editing software now supports MPEG2

editing. Editing and encoding MPEG2 requires more processing power than

DVD and should be done on well specified machines. It is not suitable for

internet delivery.

MPEG4 is a set of video and audio standards intended to deliver quality video

over limited bandwidths that also support a range of other media types such as

text, still image and animation. MPEG4 offers high quality, scalable streaming

over a range of bandwidths, including those provided by mobile networks. The

standards also include components and elements that allow the viewer to

interact with the picture on the screen or to manipulate individual elements in

real time. The MPEG4 format is a container for various versions called layers.

There are different implementations, some of which are proprietary and not

compliant with the ISO MPEG4 standard. It was 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,

problems over licensing costs and the lack of digital rights management in the

standard made many content providers slow to embrace it. These issues are

being tackled but it also faces competition from proprietary formats such as

Windows Media. MPEG4 is beginning to be supported in other areas such as

mobile video (3G), mobile television, settop boxes and video on demand(VOD).

2.3 Gigabyte (GB)

A gigabyte equals about 1,000 megabytes (MB). A Bluray Disc capable of

recording 50 GB therefore stores about 50,000 Megabytes

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 same side. The readout or recording laser of

the Bluray Disc device will first read from or record to one layer, and then

refocuses on the second layer. All this is done automatically without any user

interference. A double layer Bluray Disc can store upto 50 GB of data.


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2.5 SDTV

It stands for Standard Definition Television. Generic term used forconventional television sets, based on the NTSC or PAL standards. SD television

consists of 480 to 570 visible lines.

2.6 Numerical Aperture and Resolution

The numerical aperture of a microscope objective is a measure of its ability to

gather light and resolve fine specimen detail at a fixed object distance.

Imageforming light waves pass through the specimen and enter the objective

in an inverted cone as illustrated in Figure 1. A longitudinal slice of this cones

of light shows the angular aperture, a value that is determined by the focal

length of the objective. The angle is onehalf the angular aperture (A) and is

related to the numerical aperture through the following equation:

Numerical Aperture (NA) = n (sin )


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Where n is the refractive index of the imaging medium between the front lens

of the objective and the specimen cover glass, a value that ranges from 1.00

for air to 1.51 for specialized immersion oils. Many authors substitute the

variable for in the numerical aperture 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 whose

maximum value is 90. The sin of the angle , therefore, has a maximum value

of 1.0 (sin90 = 1), which is the theoretical maximum numerical aperture of a

lens operating 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 of 405nm.Though the

red and the green lasers were discovered much earlier, it was only in 1996 that

the blue laser was discovered. Actually, the wavelength 405nm would

correspond to the blueviolet part of the visible light, in the spectrum. This

achievement is attributed to the efforts of Shuji Nakamura of Nichia

Corporation, Japan. The device utilizes a GaN diode as its laser source. The

operating current is kept between 60mA and 70mA for optimum performance.

For writing into the disc, the power of the laser used is about 6mW. For

reading from the disc, much lesser power is required, only about 0.7mW.The

GaN source can give a power of about 65mW. So, it is an ideal choice for the

laser source to be used with the Bluray disc. Due to the much lowerwavelength involved, the amorphous mark size (bit size) is small, leading to

higher storage capacity on disc of the same size, about five to six 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 405nm than 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 about25.4 million nanometers. 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 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-


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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 lighting situations.

HD DVDs:HD (high-definition) DVDs using blue laser light could lead to fiveor 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 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.


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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.

Traditionallightbulbscreatealotofheatalongwiththelight.

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 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 use red laser light. Because of blue


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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. Blue laser 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 and biological 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 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 nextgeneration 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 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.

3.2.1 Optical parameter

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

data marks in spiral tracks.


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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 fromthe intense scan spot is absorbed, and a small, localized region heats up. The

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 onnew 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 the master that serve as data marks in the replicas. Inexpensive

replicas of the master are made with Injectionmolding equipment.


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Readout of data marks on the disk is illustrated in Fig.2, where the laser is used

at 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 ismodulated. 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 2produce the output data stream. A fundamental limitation to the number ofdata marks per unit area is due to the size of the focused laser beam that

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 spot

sizes.

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


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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 illuminationoptics, 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.

Fig 3Instead of focusing directly on the recording surface, optical disks focus

through a 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 anunacceptable threshold due to obscuration of the laser beam. This sensitivity


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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.

In order to maximize disk capacity, the optical system uses high NA and short

wavelength. 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

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 of


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aberration 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 valuesof 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

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


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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

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 themodulation 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 rounddisks 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 in Fig. 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 recordedon 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 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 multiplelayer concept. A potential

implementation 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


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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

BluRay 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

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

considerations for data management. Data management considerations have

important 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, videoformat, bitrate 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


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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 randomaccess 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 randomaccess nature of DVDs allows very efficient methods for data

compression. For example, MPEG2 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

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

these fastmoving scenes, the maximum amount ofinformation per scene is

limited only by the maximum data rate of the player. For HDTV, acceptable

picture quality is obtained by using MPEG2 with a maximum data rate of

about 1325 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 fastermoving scenes.

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

matter what the requirements of the scene. During fastmoving 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 randomaccess 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 foran equivalent length and quality HDTV presentation.

It is not practical to store HDTV on CDs and DVDs with MPEG2. For CDs,

special multiplebeam readout or high velocity disk dives could produce the

data rate, which is an advantage of the fixedbitrate 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 MPEG2. 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 MPEG2. Bluray has


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slightly higher capacity and data rate. The twohour play time for HDTV with

BluRay in Table I is really a specification for realtime recording, which is not

easily compressed into an efficient variableratescheme. BluRay should easily

provide two hours or longer of prerecorded HDTV per side compressed with

MPEG2.

MPEG2 is a technique for compressing video data and replaying the data

associated with certain rules that are defined in the MPEG2 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.

MPEG4 technology is an advanced video compression scheme that utilizes

advanced prefiltering and postfiltering, inaddition to a rulebased algorithm.

Estimated improvement in compression is a around a factor of three beyond

MPEG2.

4.Different Formats of Blueray Disc

BDROM :A read only format developed for prerecordedcontent.

BDR :A write once format developed for PC storage.BDRW :A rewritable format developed for PC storage.BDRE :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 BDR the material on the discitself 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 BDRW 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 BDRW, 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 (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 ands

have a sinus form. This is called a wobbled groove. In the groove, pits areformed to store data.


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6.Bluray Disc Structure

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

made of a spincoated UV resin. It is formed by sandwiching a transparentlayer 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 ZnSSiO2 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.

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 discreaches 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 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 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-useway. 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 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

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 ofan optical disc recording device using blue ray will start

off 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.


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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 a

result, blue laser technology has been adopted for the development of next-

generation optical discs.


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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 usesa 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 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 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 asBluray Disc. For example, its prerecorded capacities are only 15 GB for a

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

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

disc.

Although the HDDVD 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 createHDDVDs. But whats more important is that HDDVD 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

socalled cost benefit substantially. It iseven possible that the HDDVD

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 existingplayback/recording equipment. On the other hand, the Bluray 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 HDDVD format incorporates many

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

fulllength feature plus additional bonus materialsusing the MPEG2 format,

different and stronger encoding formats need to be used. Although Bluray

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

publishers can still use the MPEG2 encoding format at bit rates up to 54Mbit/sec. As MPEG2 is the defacto 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 MPEG2 encoding suite

is already 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 itsoverwhelming industrywide support.

Almost all consumer electronics companies in the world (combined market

share of about 90%) and the worlds two largest computer companies support

the Bluray Disc format.


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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 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 Bluray 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

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.


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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 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

rewriting is done repeatedly to one area of the disc most probably, the innerperimeter. This limits the disc life. But, the BDFS(Bluray 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.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 best performance and

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

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

topoftheline specifications mean that it is suitable for a full range of other

purposes as well.

14.1 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 Bluray Disc format offers consumers the 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 Bluray 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.


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14.2 High Definition Video Distribution

Due to its enormous data capacity of 25 to 50 GB per (single sided) disc, theBluray 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 Bluray Disc movie format greatly expands on traditionalDVD capabilities, by incorporating many new interactive features allowing

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

An Internetconnection 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

material as well.

14.3 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 tapebased, consumers cannot benefit from the convenience

and direct access features they are used to from the DVD players andrecorders. Now, the Bluray Disc format, with its unprecedented storage

capacity, allows for the HD video recorded with an HD camcorder to be

seamlessly transferred to a Bluray Disc. When the HD content is stored on a

Bluray Disc, it can be randomly accessed in a way comparable to DVD.

Furthermore, the Bluray 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.


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14.4 Mass Data Storage

In its day, CDR/RW meant a huge increase in storage capacity compared totraditional 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

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.

In addition, commercial storage requirements are growing exponentially due

to the proliferation of email and the migration to paperless processes. The

Bluray Disc format again offers 5 to 10 times as much capacity as traditionalDVD resulting in 25 to 50 GB of data to be stored on a single rewritable or

recordable disc. As Bluray Disc uses the same form factor as CD and DVD, this

allows for Bluray Disc drives that can still read and write to CD and DVD media

as well.

14.5 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 Bluray 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 to restore data from a storage carrier. One Bluray Disc mayreplace 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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15.Requirements

1) Blue laser

2) Detector

3) Advanced objective lens

4) New disk and cartridge manufacturing technologies

16.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

The HDDVD (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 Bluray disc.


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17.Future Developments

Efforts are progressing on many fronts to make the Bluray discs, players andrecorders 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

UVcurable resin is being used for the researches and results are encouraging.

Figure shows the cross section of the disc being developed.


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18. 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 inan 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 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 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, makingconsumer 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.


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19. REFERENCES

Websites:

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

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

http://www.bluraydisc.com/

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

Documents

48652979 Seminar Report on Blu Ray Disc