Blu-ray, also known as Blu-ray Disc (BD) is the name of a next-generation optical disc video recording format jointly developed by nine leading consumer electronics companies. The format was developed to enable recording, rewriting and playback of high-definition video (HDTV). Blu-ray makes it possible to record over 2 hours of digital high-definition video (HDTV) or more than 13 hours of standard-definition video (SDTV/VHS picture quality) on a 27GB disc. There are also plans for higher capacity discs that are expected to hold up to 50GB of data.
The Blu-ray Disc technology can store sound and video while maintaining high quality and also access the stored content in an easy-to-use way. Adoption of the Blu-ray Disc in a variety of applications including PC data storage and high definition video software is being considered.
Key Characteristics of Blu-ray discs are :
Blu-ray is a new optical disc standard based on the use of a blue laser rather than the red laser of todayâ„¢s DVD players. The standard, developed collaboratively by Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and Thomson, threatens to make current DVD players obsolete. It is not clear whether new Blu-ray players might include both kinds of lasers in order to be able to read current CD and DVD formats.
The new standard, developed jointly in order to avoid competing standards, is also being touted as the replacement for writable DVDs The blue laser has a 405 nanometer (nm) wavelength that can focus more tightly than the red lasers used for writable DVD and as a consequence, write much more data in the same 12 centimeter space Like the rewritable DVD formats, Blu-ray uses phase change technology to enable repeated writing to the disc.
Blu-rayâ„¢s storage capacity is enough to store a continuous backup copy of most peopleâ„¢s hard drives on a single disc. The first products will have a 27 gigabyte (GB) single-sided capacity, 50 GB on dual-layer discs. Data streams at 36 megabytes per second (Mbps), fast enough for high quality video recording Single-sided Blu-ray discs can store up to 13 hours of standard video data, compared to single-sided DVDâ„¢s 133 minutes. People are referring to Blu-ray as the next generation DVD, although according to Chris Buma, a spokesman from Philips (quoted in New Scientist) Except for the size of the disc, everything is different.
Blu-ray discs will not play on current CD and DVD players, because they lack the blue-violet laser required to read them. If the appropriate lasers are included, Blu-ray players will be able to play the other two formats. However, because it would be considerably more expensive, most manufacturers may not make their players backward compatible. Panasonic, Philips, and Sony have demonstrated prototypes of the new systems.
2. EVOLUTION OF OPTICAL REMOVABLE MEDIA STORAGE DEVICES
2.1 Optical Storage
Optical RMSD formats use a laser light source to read and/or write digital data to a disc. Compact disc (CD) and digital versatile disc (DVD, originally referred to as digital video disc) are the two major optical formats. CDs and DVDs have similar compositions consisting of a label, a protective layer, a reflective layer (aluminum, silver, or gold), a digital-data layer molded in polycarbonate, and a thick polycarbonate bottom layer.
Fig.2.l.1 Composition of optical disk
CD Formats include
Â¢ Compact disc-read only memory (CD-ROM)
Â¢ Compact disc-recordable (CD-R)
Â¢ Compact disc-rewritable (CD-RW)
DVD formats include
Â¢ Digital versatile disc-read only memory (DVD-ROM)
Â¢ Digital versatile disc-recordable (DVD-R)
Â¢ DVD-RAM (rewritable)
Â¢ Digital versatile disc-rewritable (DVD-RW)
Data bits are permanently stored on a CD as a spiral track of physically molded pits in the surface of a plastic data layer that is coated with reflective aluminum. Smooth areas surrounding pits are called lands. CDs are extremely durable because the optical pickup (laser light source, lenses and optical elements, photoelectric sensors, and amplifiers) never touches the disc. Because data is read through the thick bottom layer, most scratches and dust on the d surface are out of focus, so they do not interfere with the reading process.
With a 650-MB storage capacity (sometimes expressed as Ëœ74 minutes,â„¢ referring to audio playing time encoded in the original CD format), one CD-ROM disc can store the data from more than 450 floppy disks. Data access speeds are reasonable, with random access rates ranging from 80 to 120 ms for any data byte on the disc. Maximum data transfer rates are approximately 6 MB/sec. These attributes make CD-ROMs especially well suited for storing large multimedia presentations and software programs.
CD-ROM drives are distinguished by different disc rotation speeds measured relative to the speed of an audio CD player. A 1X CD-ROM accesses data at approximately 150 KB/sec, the same as an audio player. A 32 X CD-ROM reads data thirty-two times faster at approximately 4,800 KB/sec. In general, faster speeds reduce data access time, but vibration and noise problems limit maximum speeds to approximately 48X.
CD-R drives advanced a write once/read many (WORM) storage technology that appeared in the mid 1980s. CD-R drive production ended when the cost to manufacture CD-RW drives became comparable. CD-R discs accept multiple writing sessions to different sections of a disc. However, CD-ROM drives must be multi-session compatible to read any data recorded after the first writing session; all of todayâ„¢s CD-ROM drives meet this requirement.
CD-R discs use a photosensitive dye layer that can be changed (or Ëœboundedâ„¢) with a laser to simulate the molded pits of a conventional CD. The dye layer is relatively transparent until it is burned with a laser to make it darker and less reflective. CD-R discs use a gold or silver reflective layer behind the dye to produce reflectives similar to the aluminum layer used in CDs.
When a CD-R disc is read, the lands reflect laser light off of the gold or silver layer through the more transparent areas of the dye. The less reflective areas, produced from recording data on the dye, read as pits.
Like CD-Rom discs, recordable discs have 650 MB ( or 74 minutes) of storage capacity. The actual capacity of a 650-MB CD-R disc is about 550 MB when they are formatted for packet writing. Higher-capacity CD-Rs that have become available recently include:
Â¢ 700 MB (80 minutes)
Â¢ 800 MB (90 minutes)
Â¢ 880 MB (99 minutes)
The 700MB disc is the only higher-capacity option that is fully compatible with the CD-R standard CD-R drives provide reasonable average data access times typically less than 100 ms. CD-R discs are the least expensive RMSD media available, but the CD-R systems are limited as RMSDâ„¢s because they can only be written once.
CD-RW drives introduced in 1997, record data on both CD-R and CD-RW discs. CD-R.W discs use a phase-change technology to record. In place of the dye layer use din CD-R media, CD-RW discs have an alloy layer composed of antimony, tellurium, and other metals that exists in either of two stable states. This material forms a polycrystalline structure when heated above 200 degree Celsius and cooled, but also forms an amorphous or non-crystalline structure when heated above the melting point at 500 to 700 degrees Celsius and rapidly cooled. The alloy is changed between the two states using two different laser power settings.
The crystalline state for this material reflects more light than the non-crystalline form, so it simulates the lands of a regular CD. Data bits are encoded by changing small target areas to the non-crystalline form. This writing process can be repeated approximately 1,000 times per disc.
CD-RW drives write to both CD-R and CD-RW media, and permit multiple writing sessions to different sections of a disc. CD-RW drives are specified by CD-R write speed, CD-RW write speed, and CD-ROM maximum read speed (for example, 8/4/32Xis 8X CD-R write/4X CD-RW write/32X CD-ROM maximum read). The fastest CD-RW drives now provide 16/10/40X speeds for desktop systems. Transfer rates for reading data are up to 6 MB/sec and approximately 2.4 MB/sec for writing data on CD-R media.
Like the CD-R discs, the actual capacity of a 650-MB CD-RW disc is about 550 MB when formatted for packet writing. CD-RW drives have replaced the comparably priced CD-R drives, and are positioned to be a good RMSD solution.
Like CD drives, DVD drives read data through the disc substrate, reducing interferences from surface dust and scratches. However, DVD-ROM technology provides seven times the storage capacity of CD discs, and accomplishes most of this increase by advancing the technology used for CD systems. The distance between recording tracks is less than half that used for CDs. The pit size also is less than half that on CDs, which requires a reduced laser wavelength to read the smaller-sized pits. These features alone give DVD-ROM discs 4.5 times the storage capacity of CDs;
188.8.131.52 Single Layers and Dual Layers
DVD discs have a much greater data density than CD discs, and DVD-ROM drives rotate the disc faster than CD drives. This combination results in considerably higher throughput for DVD technology. A 1X DVD-ROM drive has a data transfer rate of 1,250 KB/sec compared with a 150-KB/sec data transfer rate for a 1X CD-ROM drive. Current DVD-Rom drives can read DVD discs at 16X (22 MB/sec) maximum speeds and can read CDs at 48X (7.5 MB/sec) maximum speeds.
DVD-ROM discs provide a 4.7-GB storage capacity for single-sided, single data-layer discs. Single-sided, double data-layer discs increase the capacity to 8.5 GB. Double-sided, single data layer discs offer 9.4 GB, and double-sided, double data-link layer discs provide 17 GB of storage capacity. DVD-ROM drives also read CD-ROM, CD-R, CD-RW, and DVD-R discs. As new software programs push the storage limits for CD-ROM discs.
21.4.2 DVD Storage Versions
DVD-R drives were introduced in 1997 to provide write-once capability on DVD-R discs used or producing disc masters in software development and for multimedia post-production. This technology, sometimes referred to as DVD-R for authoring, is limited to niche applications because drives and media are expensive.
DVD-R employ a photosensitive dye technology similar to CD-R media. At 3.94 GB per side, the first DVD-R discs provided a little less storage capacity than DVD-ROM discs. That capacity as now been extended to the 4.7 GB capacity of DVD-ROM discs.
The IX DVD-R data transfer rate is 1.3MB/sec. Most DVD-ROM drives and DVD video players read DVD-R discs. Slightly modified DVD-R drives and discs have recently become available for general use.
DVD-Ram (rewritable) drives were introduced in 1998. DVD-Ram devices use a phase-change technology combined with some embossed land/pit features. Employing a format termed Ëœland groove,â„¢ data is recorded in the grooves formed on the disc and on the lands between the grooves. The initial disc capacity was 2.6 GB per side, but a 4.7-GB-per-side version is now available.
Each DVD-RAM disc is reported to handle more than 100,000 rewrites. DVD is specifically designed for PC data storage; DVD-RAM discs use, a storage structure based on sectors, instead of the spiral groove structure used for CD data storage. This sector storage is similar to the storage structure used by hard drives. Sector storage results in faster random data access speed.
Because of their high cost relative to CD-RW technology, current consumer-oriented DVD RAM drives and media is not a popular choice for PC applications. Slow adoption of DVD-Ram reading capability in DVD-ROM drives has also limited DVD-RAM market acceptance.
The DVD-RW drive format is similar to the DVD-R format, but offers rewritability using a phase-change recording layer that is comparable to the, phase-change layer used for CD-RW. DVD-RW is intended for consumer video (non-PC) use, but PC applications are also expected for this technology. The first DVD-RW drives bases on this format, which also record DVD-R discs, were introduced in early 2001.
2.2 DVD vs. CD
DVD has a more efficient error correction code (ECC). Fewer data bits are required for error detection, thus freeing space for recorded data. DVD discs can also store two layers of data on a side by using a second data layer behind a semitransparent first data layer laser to switch between the two data layers.
DVD drives can also store data on both sides of the disc. Manufacturers deliver the two-sided structure by bonding two thinner substrates together, providing the potential to double a DVDâ„¢s storage capacity. Single-sided DVD disc have the two fused substrates, but only one side contains data.
CD-RW and DVD-ROM combination
A combination CD-RW/DVD-R0M device, commonly called a ËœComboâ„¢ drive, has been available since 1999. Combo drives need a high-power laser for CD-R/CD-RW writing, and a different laser and decoding electronics for reading DVDs. A Combo drive provides additional functionality for PCs, and is especially valuable for space-constrained portable systems.
Floppy disk Compact disc (CD) Digital Video Disc (DVD) Blu-ray disc
Capacity 1.44MB 650-880MB 4.7-20GB 23.3-50GB
Transfer Rate 0.06 MB/s 3.5 MB/s 22.6MB/s 36MB/s
Interface IDE IDE/SCSI-2 IDE/SCSI-2 IDE/SCSI-2
3. BLU-RAY DISC KEY CHARACTERISTICS
3.1 Large recording capacity up to 27GB
By adopting a 405nm blue-violet semiconductor laser, with a 0.85NA field lens and a 0.1 mm. 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)
3.2 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 discâ„¢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.
3.3 Easy to use disc cartridge
An easy to use optical disc cartridge protects the optical discâ„¢s recording and playback phase from dust and fingerprints.
3.4 Main Specifications
Recording capacity 23.3GB/25GB/27GB
Laser wavelength 405 nm, (blue-violet laser)
Lens numerical aperture (NA) 0.85
Data transfer rate 36Mbps
Disc diameter 120mm
Disc thickness 1.2mm
Recording format Phase change recording
Tracking format Groove recording
Tracking pitch 0.32um
Shortest pit length 0.160/0.149/0.l38um
Recording phase density 16.8/18.0/1 9.5Gbit/inch2
Video recording format MPEG2 video
Audio recording format AC3, MPEG1, Layer2, etc.
Video and audio multiplexing format MPEG2 transport stream
Cartridge dimension Approximately 129 x 131 x 7mm
4. BLUE LASER
A blue laser is a laser (pronounced LAY-zer) with a shorter wavelength than the red laser used in todayâ„¢s compact disc and laser printer technologies and the ability to store and read two to four times the amount of data. When available in the marketplace, personal computer users may be able to buy a laser printer with a resolution up to 2400 pixels or dots per inch at an affordable price. The same technology in CD and DVD players will provide a dramatic breakthrough in storage capability without an increase in device size.
A laser (an acronym for light amplification by stimulated emission of radiation) is a coherent (meaning all one wavelength, unlike ordinary light which shower on us in many wavelengths) and focused beam of photons or particles of light. The photo are produced as the result of a chemical reaction between special materials and then focused into a concentrated beam in a tube containing reflective mirrors. In the blue laser technology, the special material is gallium nitride. Even a small shortening of wavelength of light can have a dramatic effect in the ability to store and access data. A shorter wavelength allows a single item of data (0 or 1) to be stored in a smaller space.
Red lasers used in todayâ„¢s technologies have wavelengths of over 630 nanometers (or 630 billionths of a meter). The blue laser has a wavelength of 505 nanometers.
Shuji Nakamura, a Japanese researcher working in a small chemical company, Nichia chemical Industries, built the first blue laser diode. However, a number of companies have announced progress in the ability to manufacture blue laser diodes and there are now prototypes of working DVD writers and players. Recently, a standard called Blu-ray has been developed for the manufacture of blue laser optical disc technology.
4.1 Blue â€Violet Laser
SANYO has developed the worldâ„¢s first blue-violet laser diode with a new low-noise (stable) beam structure produced using ion implantation. The stable beam structure boasts lower noise, and current consumption achieving higher performance compared with conventional blue- violet laser diodes. This structure makes SANYOâ„¢s blue-violet laser diode an optimum light source for large-capacity optical disc systems like Blu ray disks.
Â¢ SANYOâ„¢s original ion implantation technology has yielded the worldâ„¢s first blue- violet laser diode with a new stable beam structure that generates a low-noise beam
Â¢ The stable beam structure produces a vastly improved stable laser beam, which yields the low-noise, low-operating current characteristics that are required in a light source for next-generation large-capacity optical disc systems like advanced DVDs require
Â¢ The laser diode is easily mass produced because the stable beam structure reduces the number of fabrication steps while the top and bottom electrodes structure reduces chip size
Laser diodes are key components in the field of optical data processing devices. SANYOâ„¢s aggressive efforts in this area led to the mass production and sales of AlGaAs (aluminum-gallium-arsenide) infrared and AlGaInP (aluminum-gallium-indium-phosphide) red laser diodes widely used in measuring instruments and a variety of optical data processing devices like CD and DVD optical disc systems.
In recent years, the field of optical disc systems has seen the development of next- generation large-capacity optical disc systems like advanced DVDs that can record more than two hours of digital high-definition images. The blue-violet laser diode made of InGaN (indium gallium-nitride) that is used as a light source for reading signals recorded on the optical discs was the key to developing these systems. Naturally demand for the laser diode is expected to rise sharply as more large-capacity optical disc systems become available and become more widely used.
In order to realize a blue-violet laser diode SANYO has developed original crystal and device fabrication technologies over the years. Now these fundamental technologies have yielded the worldâ„¢s first low-noise beam, blue-violet laser diode with a new stable beam structure that lowered noise and current consumption for higher performance. This development can make large-capacity optical disc systems like advanced DVDs practical.
Features of the new technology
Â¢ The new stable beam structure made by ion implantation significantly improves laser beam stability and yields the low-noise, low-operating current characteristics that the optical disc system requires.
Â¢ The laser diode is easily mass-produced because the newly developed stable beam structure reduces the number of fabrication steps while the top and bottom electrodes structure reduces chip size.
Â¢ Fundamental traverse mode
The fundamental traverse mode generates a single stable beam which means the beam can be focused into a tiny spot using a simple optical system.
The package is compact at just 5.6 mm in diameter.
Â¢ Advanced DVDs as well as for Polarity
A positive (+) or negative (-) power supply can be selected
Â¢ Built-in photodiode for monitoring optical output
A photodiode is installed to monitor optical output
The new laser diode is suitable for the next-generation large-capacity optical disc systems like and many types of measuring instruments.
Â¢ Blue-violet laser diode
This is the light source used to read signals (pits) on discs in next-generation large-capacity optical disc systems. There is no way the size of beams from the infrared and red laser diodes now used in CDs and DVDs can be reduced to the size of a pit recorded on these, discs in c optical systems. The shorter wavelength of the blue-violet laser diode however allows the beam to be focused into a reduced spot, and therefore is the key to next-generation large-capacity optical disc systems.
Â¢ Stable beam structure
The newly developed stable beam structure was produced using ion implantation. With mode c9ntrol Ëœof the laser beam and current confinement, the implanted layer significantly improves laser beam stability and yields the low-noise, low-operating current characteristics that an optical disc system requires
Â¢ Ion implantation
This technology uses a strong electric field to force ionized atoms into a semiconductor. It is mainly used in Si LSI production for doping impurities in semiconductors. The amount and depth of the atoms implanted into the semiconductor can be precisely Ëœcontrolled with consistent reproducibility
Â¢ Fundamental traverse mode
This refers to a mode where distribution of light intensity in a laser beam forms a single peak.
5. ACCESSING THE DISC
5.1 Phase change recording
Fig.5. 1.1 Phase change recording mechanism
The basic concept in phase change memories starts with the use of a material which can exist in two separate structural states in a stable fashion. An energy barrier must be overcome before the structural state can be changed, thereby providing the stability of the two structures. Energy can be supplied to the material in various ways, including exposure to intense laser beams and application of a current pulse. Laser exposure is used for recording and erasing in the case of an optical memory. If the energy applied exceeds a threshold value, the material will be excited to a high mobility state, in which it becomes possible to rapidly rearrange bond lengths and angles by slight movement of the individual atoms. In lone pair materials divalently bonded this may simply be shifting of non-bonding or weakly bonding lone pairs to make new connections. In a material such as germanium compositions can be selected in which these minute changes in bonding position of the atoms can cause profound changes in the physical properties of the material, including its optical absorptivity and reflectivity.
The importance of the composition lies in the selection of a material composition which can form a crystalline structure without phase segregation. Selection of an appropriate composition and inducing high mobility state during laser exposure are the underlying principles in direct- overwrite phase change erasable optical recording media. Our early work established that materials in the Ge-Sb-Te ternary are capable of rapid transition between the two states, and our later work in the investigation of the relationship between the crystalline properties and the performance of various materials applied as optical recording media clarifies the reasons for the importance of the composition (7,8). Direct-overwrite is simply the process of recording new information in a location which had been previously recorded without first erasing the old information. Two major material properties are required to provide this capability, First, the speed of the transition must be very fast.
The structure of the current phase change erasable materials can easily be transformed in either direction by pulses of 50 nanosecond duration. Second, the energy delivered by the laser beam, at both the amorphizing or crystallizing power levels must be equally absorbed by the phase change material when it is in either structural state. The indexes of refraction and the absorption coefficients of the phase change material in its two structural states inherently provide this capability, and appropriate design of the optical stack used to form the device provides the final tuning. The large differences in optical constants between the two structures leads to a major advantage of phase change optical disks in that the read contrast is very high. The two structures, have very different reflectivities, an attribute which leads to manufacturability with relaxed layer thickness tolerances. Contrasted to the competing magneto-optical disks, which have a small read contrast, and further, have a read signal which must be differentiated by a more complex evaluation of polarization, phase change disks can be manufactured more economically.
The device structures used in products produced by our licensees are sophisticated designs which apply principles we established for the protection of the phase change alloy from atmospheric contamination and chemical interaction with the protective layer itself with enhanced optical coupling and careful handling of the thermal considerations involved in the interaction of the memory alloy with the laser light. High yield consistent manufacturing is of course a major consideration in the production of any product, and our licensees have done an outstanding job of developing a well controlled process with good yield. Use of materials which have the same composition in the amorphous and crystalline phases also provides long life. Since no diffusion is involved in the phase change process, no phase segregation occurs and life is only limited by the integrity of the Substrate. A plastic such as polycarbonate will begin to show degradation in its surface smoothness after 100,000 re-writes, and will contribute to a background noise level which will limit cycle life to about one million cycles. Disks made with advanced plastics or glass, or those which use dielectric layers more effective in stabilizing the plastic surface will have a much longer cycle life.
Once the substrate material has been formatted, the roll is placed in a vacuum chamber and the layers of the phase change and encapsulation materials are coated, again in a continuous process, The roll of coated media is then laminated to a somewhat thicker polycarbonate film, which serves as the Cover slip to provide for dust and scratch protection required in a durable product. The final manufacturing step is simple stamping of the individual formatted disks from the web. The great advantage of this production technique is its low cost. Not only does the continuous process red manufacturing costs, but the selection of disk diameter allows linear control of the cost per disk.
5.2 Groove Recording
The physical surface of the disc consists of lands and grooves. In Blu-ray discs, data is written only onto the grooves. In phase change discs the groove depth is designed to be ?/6n, where ? is the pickup user wavelength and n is the optical index of the substrate. This reduces cross talk between the lands and the grooves, and allows conventional tracking signal schemes to be used with narrow track pitches.
Fig.5.2. I groove recording
The figure above shows a typical Blu-ray structure. A Blu-ray disc holds 23.3/ 27 GB per side. This high recording density was achieved through the use of mark edge recording, along with the use of groove recording, which is effective for use with narrow track pitches recording, in which data is recorded only within the tracking grooves. There is a limit to how much track pitch can be reduced as a means of increasing recording density, as narrow track pitch tends to weaken the tracking servo signal and increase crosstalk The solution is groove recording In phase change discs the groove depth is designed to be la/6n, where is the pickup laser wavelength and n is the optical, index of the substrate. This reduces crosstalk between the lands and the grooves, and allows conventional tracking signal schemes to be used with narrow track pitches. The reduction in crosstalk with the land and groove method is a result of the fact that the reduction in reflected light due to interference with a neighboring track when in crystalline state is approximately the same as decrease in reflectivity when in amorphous state at a particular depth. That depth is about lambda/6n, which is about 36 nm for a 405nm laser wavelength. Blu -Ray uses this kind of land and groove recording, with a track pitch of 0.32 ?m.
6.1 Ultra Density Optical (UDO)
UDO is the next generation of 5.25 professional optical storage technology. It is a convergent technology that delivers the performance of 5.25 MO, the longevity 12-inch WORM, and the cost effectiveness of DVD. It utilizes violet laser and phase change media recording technology to provide a quantum leap in data storage densities. First generation UDO products will be 30GB capacity and are scheduled to ship in August 2003. Future generations will increase capacity to 60GB and 120GB and will provide full backward read compatibility. Both WORM and rewritable media will be available and the cartridgeâ„¢ will be physically identical to 5.25 MO to maintain library compatibility. Target markets include archiving, document imaging, call centers, e-mail archiving, GIS, medical, telecom, banking, insurance, legal and government.
UDO is the application of Blu-ray consumer recording technology to the professional optical storage market. Blu-ray is the proposed successor to DVD and uses phase change recording technology to provide the storage capacity to record aâ„¢ full-length HDTV video. The use of violet lasers and high NA optics dramatically increases data storage densities and necessitates a new type of disk construction with a 0.1mm cover layer to protect the data surface. As with existing MO technology, UDO uses non contact recording to provide robust and reliable performance.
6.2 Digital Video Recording
The Bin-ray Disc using Ëœblue-violet laser achieves over 2-hour digital high definition video recording on a 12cm diameter CD/DVD size phase change optical 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/DVI) size disc using a 405nm blue-violet laser. By employing a short wavelength blue violet laser, the Blu Disc successfully minimizes its beam spot size by makingâ„¢ 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 Discâ„¢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 rec9rded. 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 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 Discâ„¢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
7. FUTURE DEVELOPMENT
Â¢ Large capacity:- sided double layer for 50 (113 by using t multilayer technology.
Â¢ High Speed Transfer Rate:-To realize higher recording performance
Â¢ Media family:- ROM,R( Write Once)
Â¢ Application:- Adoption in a variety of applications including PC data storage and high definition video software.
8.1 The Blu-ray Impact
Blu-ray is expected to challenge DVDâ„¢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 video-an application in which more than 10GB of storage space is filled up with just one hour of video-will get a major boost. Conversely, the format could take advantage of the spread of high-definition television. As Blu-ray Disc uses MPEG-2 Transport Stream compression technology, recording for digital broadcasting would become easier 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 Discâ„¢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.
8.2 Not Beaming As Yet
However, it will be many years before the Blue-ray finds such high-demand applications. Blu-ray compatible systems arc likely to hi the market only in 2003. The nine companies involved have just begun work on the hardware. Licensing for technology to play the discs will start within the next few months. Cost will also play a crucial role in the development of commercial systems. A sample blue-laser diode currently costs .around $1,000, making consumer products based on it unrealistic. I however, the price of a blue-laser diode is expected to tumble once Nichia Corpâ€the major source for blue lasersâ€begins commercial production. The biggest question that is plaguing the industry is whether current DVD discs will be compatible with the new machines. Wary of alienating DVD fins, the companies are looking for ways to make the new products compatible with DVDs.
8.3 A Uniform Picture
Buoyed by the expected price fall, many electronics companiesâ„¢ began to work on blue-laser based development systems in the last few months and Blu-ray is a direct outcome of these efforts. The similarity of the work being done prompted the companies to look for a standard format that would wipe out the differences between those made by individual companies. The companies had learnt the need for a standard format the hard way a la DVDs.
8.4 The Jarring Image
However, it appears that not everyone has learnt from the DVD episode. As Blu-ray moves towards commercialization, it could ignite a new format battle Among the Blu-ray group are six of the 10 companies that worked, on developing the DVD format. Four of DVDâ„¢s main backers-Mitsubishi, AOL Time Warner, Victor of Japan and Toshiba Corp-- are staying away from the Blu-ray consortium. Toshibaâ„¢s absence is the most conspicuous. The company has publicly stated that it intends to propose its prototype blue-laser optical-disc format. Consequently, its absence raises the possibility that a format battle may be about to begin again. Lending credence to this theory is the fact that the nine companies, which are also on the steering committee of the DVD Forum, are conducting the Blu-ray work outside of the Forum Much like the DVD story, the battle isnâ„¢t going to end soon. But a compromise formula can be worked out Already, there is evidence of concessions to get major players around a single format The Blu-ray groupâ„¢s announcementâ„¢ that discs are expected to be available in three different sizes, is one such example. Some companies want to keep the price of discs low by using cheaper materials that will be able to hold slightly less data
8.5 Future Perfect
Despite the impending tug-of war, the industry is excited, about the future prospects, of this technological innovation The industry is of the view that Blu-may has the potential to replicate, if not better, the DVD success story. The expected upswing in high-definition television adoption and broadband implementation could act as the catalyst. Aware that the recession in economies across the globe could come in the way of high-definition television broadband penetration, major players are exploring the ways In make Blu-ray compatible with DVDs. Cost can dampen the sales in the first year. Owing to th patent and the technology involved, Blu-ray is likely to cost more than DVDs. But sooner than later, it will move towards commodity pricing. Once that happens, Blu-ray holds the promise to steal a march over its immediate predecessor.
World Wide Web
Â¢ A History Of the Phase Change Technology Stanford Ovshinsky, president of Energy Conversion Devices
Â¢ Removable Media Storage Devices Tom Pratt and Chris Steenbergen, Storage Technology
I express my sincere gratitude to Dr. Agnisarman Namboodiri, Head of Department of Information Technology and Computer Science, for his guidance and support to shape this paper in a systematic way.
I am also greatly indebted to Mr. Saheer H. and Ms. S.S. Deepa, Department of IT for their valuable suggestions in the preparation of the paper.
In addition I would like to thank all staff members of IT department and all my friends of S7 IT for their suggestions and constrictive criticism.
1. Introduction Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 01
2. Evolution of Optical Removable Media Storage DevicesÂ¦Â¦... 02
2.1 Optical Storage Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 02
2.1.1 CD-ROM Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 03
2:1.2 CD-RÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 04
2.1.3CD-RW Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 05
184.108.40.206 Single Layers and Dual LayersÂ¦Â¦Â¦Â¦. 06
220.127.116.11 DVD Data Storage VersionsÂ¦Â¦Â¦Â¦Â¦. 07
18.104.22.168.1 DVD-R Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦... 07
22.214.171.124.2.DVD-RAM Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 08
126.96.36.199.3DVD-RW Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 08
2.2 DVDvs.CDÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 09
3. Blu-ray Disc Key CharacteristicsÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 10
3.1 Large recording capacity up to 27GB Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 10
3.2 High-speed data transfer rate 36MbpsÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 10
3.3 Easy to use disc cartridge Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 10
3.4 Main SpecificationsÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 11
4. Blue Laser Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 12
4.1 Blue-Violet laserÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 13
5. Accessing the Disc Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦... 17
5.1 Phase change recordingÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 17
5.2 Groove RecordingÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦... 20
6. ApplicationsÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 22
6.1 Ultra Density Optical (UDO)Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 22
6.2 Digital Video RecordingÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 23
7. Future development Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 24
8. Conclusion Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦... 25
8.1 The Blu-ray Impact Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦ 25
8.2 Not Beaming As YetÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 26
8.3 A Uniform PictureÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 26
8.4 The Jarring ImageÂ¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦. 27
8.5 Future Perfect Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 27
9. Bibliography Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦Â¦.. 29