A
TECHNICAL
PAPER PRESENTATION
On
BLUE-RAY DISC
www.studentseminars.in
abstract:
Blue-ray disc (BD) is a next generation optical disc format meant for storage of high definition video and high –density data. As compared to the HDVD format, its main competitor, Blu-ray has more information capacity per layer, 25 instead of 15 gigabytes. Blu-ray dics not only have more storage capacity than traditional DVDs, but they also offer a new level of interactivity. Users will be able to connect to the internet and instantly download subtitles and other interactive movie features.
Blu-ray gets its name from the shorter wavelength (405 nm) of a “blue” (technically blue-violet) laser that allows it to store substantially more data than a DVD, which has the same physical dimensions but uses a longer wavelength(650 nm red laser).
There are plans for BD-ROM (read only), BD (recordable) and BD-RE (rewritable) drives for PCS and with the support of the manufacturers, it’s very likely that the technology will be adopted as the next-generation optical disc format for PC data storage and replace technologies such as DVD+-R, DVD+-RW, and DVD+-RAM.
INTRODUCTION TO BLUE-RAY DISC
A current, single-sided, standard DVD can hold 4.7 GB (gigabytes) of Information. That's about the size of an average two-hour, standard-definition movie with a few extra features. But a high-definition movie, which has a much clearer image (see how Digital Television Works), takes up about five times more bandwidth and therefore requires a disc with about five times more storage. As TV sets and movie studios make the move to high definition consumers are going to need playback systems with a lot more storage capacity.
Blu-ray is the next-generation digital video disc. It can record, store and play back high definition video and digital audio, as well as computer data.
The advantage to BIu-ray is the sheer amount of information it can hold:
· A single-layer BIu-ray disc, which is roughly the same size as a DVD, can hold up to 27 GB of data that's more than two hours of high-definition video or about 13 hours of standard video.
· A double-layer Blu-ray disc can store up to 54 GB, enough to hold about 4.5 hours of high-definition video or more than 20 hours of standard video ..
BLU-RAY VS. DVD CAPACITY
ADVANTAGES OF BLU_RAY DISC:
· Record High-Definition Television (HDTV) without any quality loss.
· Instantly skip to any spot on the disc.
· Record one program while watching another on the disc
· Create play lists.
· Edit programs recorded on the disc.
· Automatically search for an empty space on the disc to avoid recording over a program.
· Access the web to down load subtitles and other extra features
WORKING OF BLU_RAY:
Discs store digitally encoded video and audio information in pits spiral grooves that run from the center of the disc to its edges. A laser reads the other side of these pits the bumps to play the movie or program that is stored on the DVD. The more data that is contained on a disc, the smaller and more closely packed the pits must be. The smaller the pita (and therefore the bumps), the more precise the reading laser must be.
Unlike current DVD’s, which use a red laser to read and write data, Blu-ray uses a blue laser (which is where the format gets its name). A blue laser has a shorter wavelength (405 nanometers) than a red laser (650 nano meters). The smaller beam focuses more precisely, enabling it to read information recorded in pits that are not only 0.15 microns long this is more than twice as small as the pits on a DVD.Plus, Blue-ray has reduced the track pitch from 0.74 microns to 0.32 microns. The smaller pits, smaller beam and shorter track pitch together enable a single-layer Blu-ray disc to hold more than 25GB of information about five times the amount of information that can be stores on a DVD.
Each BIu-ray disc is about the same thickness (1.2 millimeters) as a DVD. But the two types of discs store data differently. In a DVD, the data is sandwiched between two polycarbonate layers, each O.6-mm thick. Having a polycarbonate layer on top of the data can cause a problem called birefringence, in which the substrate layer refracts the laser light into two separate beams. If the beam is split too widely, the disc cannot be read. Also, if the DVD surface is not exactly flat, and is therefore not exactly perpendicular to the beam, it can lead to a problem known as disc tilt, in which the laser beam is distorted. All of these issues lead to a very involved manufacturing process.
BUILDING OF BLU-RAY:
The BIu-ray disc overcomes DVD-reading issues by placing the data on top of a l.l-mmthick polycarbonate layer. Having the data on top prevents birefringence and therefore prevents readability problems. And, with the recording layer sitting closer to the objective lens of the reading mechanism, the problem of disc tilt is virtually eliminated. Because the data is closer to the surface, a hard coating is placed on the outside of the disc to protect it from scratches and fingerprints.
The design of the BIu-ray discs saves on manufacturing costs. Traditional DVDs are built by injection molding the two O.6-mm discs between which the recording layer is sandwiched. The process must be done very carefully to prevent birefringence.
1. The two discs are molded.
2. The recording layer is added to one of the discs.
3. The two discs are glued together.
BIu-ray discs only do the injection-molding process on a single I.I-mm disc, which reduces cost. hat savings balances out the cost of adding the protective layer, so the end price is no more than the price of a regular DVD.
BLU-RAY VS OTHER NEW DISC FORMATS:
Will Blu-ray replace previous DVDs? Its manufactures hope so. In the meantime JVC has developed a Blu-ray /DVD combo disc with an approximate 33.5GB capacity, allowing for the release of video in both formats on a single disc. But Blu-ray is not alone in the marketplace. A few other formats are competeting for a share of DVD market.
HD-DVD:
The other big player is HD_DVD, also called AOD(Advanced Optical Disc), which DVD and can therefore be manufactured with the same equipment, saving on costs. The disadvantage is that it can’t match the storage capacity of Blu-ray. A rewritable, single layer HD_DVD can hold 20 GB of data; a double –layer disc can hold 30 GB(that’s compared to 27 GB and 50 GB for Blu-ray). The read-only versions hold slightly less data. Also, HD_DVD doesn’t offer the interactive capabilities of Blu-ray , although it will probably be less expensive than its competitor
OTHER COMPETETORS:
Blu-ray and HD-DVD are the two major competitors in the market, there are other contenders, as well. Warner Bros. Pictures has developed its own system, called HD-DVD-9. This system uses a higher compression rate to put more information (about two hours of high –definition video) on a standard DVD. Taiwan has created the Forwarded Versatile Disc(FVD), an upgraded version of today’s DVDs that allows for more data storage capacity (5.4 GB on a single –sided disc and 9.8 GB on a double-sided disc). And China has introduced the Enhanced Video Disc (EVD), another high-defnition video disc
There are also professional versions of the Blu laser technology. Sony has developed XDCAM and ProData (Professional Disc for Data). The former is designed for use by broadcasters and AV studios. The latter is primarily for commercial data storage (for example ,backing up servers).
WHEN WILL BLUE RAY BECOME AVAILABLE
Blu-ray recorders are already available in Japan, where more consumers have access to HDTV than in the United States. Outside of Japan, once more TV sets come equipped with a high-definition tuner and more films and television shows are produced in high-definition ( which is expected to happen by late 2005 or 2006), BIu-ray movies and TV shows on disc should become widely available. But the format is already available for home recording, professional recording and data storage.
Another important factor is cost. Just as with most new technologies, Blu-ray equipment will be pricey at first. In 2003, Sony released its first BIu-ray recorder in Japan with a price tag of around $3,000. The price is expected to drop as the format gains popularity. Blu-ray discs may also be initially more expensive than today's DVDs, but once demand grows and they can be mass-produced, manufacturers say the price will drop to within 10 percent of the price of current DVDs.
Even when the new video standard begins to replace current technologies, consumers won't have to throw away their DVDs, but they will need to invest in a new player. The industry is planning to market backward-compatible drives with both blue and red lasers, which will be able to play traditional DVDs and CDs as well as Blu-ray discs.
The Play station 3 will be the first Blu-ray accessable player.
The first BIu-Ray recorder was unveiled by Sony and was introduced to the Japanese market. JVC and Samsung Electronics announced Blu-ray based products at IFA in Berlin, Germany.
Sony has announced that the PlayStation 3 will be shipped with a Blu-Ray drive, but possibly just a read-only one. Sony's machine will also support BD-ROM pre-recorded media, which are expected to be available in early 2006.
PC DATA STORAGE
Hewlett Packard has announced plans to sell Blu-ray-equipped desktop PCs and laptops. In December 2005, HP announced that they would also be supporting the rival HD DVD technology. Philips was scheduled to debut a Blu-ray computer drive in the second half of 2005, but it was also delayed. On March 10, 2005 Apple Computer joined the Blu-ray Disc Association.
CONCLUSION:
Blu-ray disc has been a consistent road map to emerging disc technologies. Blue-ray can store up to 54 GB, enough to hold about 4.5 hours of high -definition video or more than 20 hours of standard video. And there are even plans in the works to develop a disc with twice that amount of storage.
It’s very likely that the technology will be adopted as the next generation optical disc format for PC data storage and replace technologies such as DVD+-R, DVD+-RW, and DVD-RAM.
