12-05-2010, 11:19 PM
blu-ray.doc (Size: 86 KB / Downloads: 92)
CONTENTS
ABSTRACT
INTRODUCTION TO BLU-RAY
BLU-RAY VS HD DVD
BUILDING OF BLU-RAY
WORKING OF BLU-RAY
OPERATING SYSTEM SUPPORT
ADVANTAGES & DISADVANTAGES
APPLICATIONS
CONCLUSION
ABSTRACT
In the year 1997 a revolutionary new technology brought music, video entertainment with high definition into the homes in the world and revolutionizing the entertainment industry and that was DVD. Now around after ten years of such an invention in 2006, yet another high definition and highly revolutionizing technology is getting common which is called the Blue-ray technology. Here in this invention discs are called the Blue-ray Discs (BD). These discs have very high storage capacity and can play high quantities of audio, video of high definition together with datas, photos and many varieties of digital contents.
The development effort has differed sharply from the industry efforts that produced CD and DVD technologies. These technologies were marked by compatibility problems associated with competing formats and the fact that they were released in phases. Their writable and rewritable versions designed for PC applications were not developed and released until well after their initial read-only versions. For example, music CD formats were developed and released first, followed by the formats used for PC data storage and backup. The result was a period of transition often marked by incompatibility between discs and drives.
In contrast, Blu-ray Disc technology has broad industry support and was designed from the beginning to accommodate the requirements of PC and consumer electronics applications. In addition, all the formatsâ€read-only, writable, and rewritableâ€will be released simultaneously. This strategy, coupled with an industry compatibility program, should avoid the compatibility issues experienced with previous optical storage technologies. Blu-ray Discs will be readable in any Blu-ray Disc drive, whether it is in a consumer electronics device or a PC.
Moreover, the discs use the same form factors as existing CD and DVD optical discs.
Introduction to BLU-RAY:
Blue violet laser is used in the Blue-ray discs for reading the information as it has shorter wavelength of 405 nm. Single layered Blue ray discs can store 25 gigabytes which is 5 times more than the DVD ingle layered that can store 4.7 GB. If it is double layered BD it stores 50 GB that is 6 times more than the Double layered DVD can store. The advantages in this blue ray technology over the normal DVD is that user can jump to any point on the disc instantly. High Definition Television can be recorded without the loss of any Quality. User can enjoy recording one program while playing another program on that disc. Recorded program can be edited or reordered. Playlists can be created. Space in the disc can be automatically searched for avoiding overwriting.
In the blue ray discs the data is placed on top of the polycarbonate layer that is 1.1mm thick, this placing of data prevents the reading problems as birefringence is prevented. Outside of the disc is provided with hard coating to protect it from scratches and the fingerprints. Blue ray discs will not be expensive as the production cost of them is less. In a DVD the recorded layer is kept in between two 0.6mm thick discs and then they are molded, and this process requires to be done carefully to avoid birefringence. But for blue ray discs injection molding is done on a single 1.1mm disc. BDs transfer the data very fast with rate of 36 Mbps where as the DVDs transfer at 10 Mbps.
Technical specifications:
* About 9 hours of high-definition (HD) video can be stored on a 50 GB disc.
* About 23 hours of standard-definition (SD) video can be stored on a 50 GB disc.
* On average, a single-layer disc can hold a High Definition feature of 135 minutes using MPEG-2, with additional room for 2 hours of bonus material in standard definition quality. A dual layer disc will extend this number up to 3 hours in HD quality and 9 hours of SD bonus material.
allowing for backward compatibility. In fact, it is expected that Blu-ray Disc drives will be available at launch that can read and write CDs, DVDs, and Blu-ray Discs.
BLU-RAY VS HD DVD :
Now the argument is whether the BDs replace the DVDs, and the manufacturers of the BDs are very hopeful of that, and a company has already developed a Blu-ray/DVD combo disc with around 33.5 GB capacity. As BDs is strong competitor for the DVD there are other equivalent competitors coming for replacing of the DVDs like HD-DVD which is called as AOL (Advanced Optical Device) developed by Toshiba and NEC. But still the blu-ray technology has an edge when compared and next it will be the BDs instead of DVDs. But threat can be from the Pioneerâ„¢s featured technology disc that is said to be of 500 GB capacity and can blow out the hard discs in the systems, this technology is said to use direct ultra violet rays which have even very shorter wavelength than the Blue light.
The Format Wars:
DVDs are the current standard for data storage, and perhaps more importantly the publishing format standard as well. The question is however, how much longer will they be sufficient? A much anticipated battle, or Ëœformat warâ„¢ if you will, is in progress similar to that seen in the 1980â„¢s between VHS and Betamax. This time around the same companies have fallen into the same camps and war is ensuing between Blu-ray and HD DVD technology.
Blu-ray discs (BDs) have the same physical dimensions as CDs and DVDs. But just as DVD provided a substantial increase in storage capacity compared to CD, Blu-ray Disc represents an increase over DVD capacity by 5 to 10 times.
Similar to CD, Blu-ray Disc is being manufactured as a single substrate disc,which is unlike DVD. This manufacturing process does not require the bonding of two substrates, resulting in less production material, shorter production time, and ultimately lower production costs per disc.
Blu-ray formats:
The three types of Blu-ray formats planned: BD-ROM for pre-recorded media such as software, games and movies BD-R (recordable) for HDTV recording and PC data storage BD-RE (rewritable) for HDTV recording and PC data storage
As with all new technology it will initially be more expensive to run.
Capacities:
Blu-ray supports more data capacity per layer compared to HD DVDs. That is 25GB per layer versus 15GB of HD DVD. Technically it can fit three different capacities; 25GB is merely the average, these capacities are 23.3GB, 25GB or 27GB. This equates to over 4 hours of high definition video with audio.
There is also the option of dual-layers: 46.6GB, 50GB or 54GB, which is roughly 8 hours. Currently BDA are researching 100GB and 200GB technology with 4 or 8 layers, this keeps the technology Ëœfuture proofâ„¢. Also in the works is an 8cm disc variation with a 15GB capacity, rather than the regular 12cm discs.
Building a Blu-ray Disc:
Unlike current DVDs, 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 nanometers). The smaller beam focuses more precisely, enabling it to read information recorded in pits that are only 0.15 microns (µm) (1 micron = 10-6 meters) long -- this is more than twice as small as the pits on a DVD. Plus, Blu-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 25 GB of information -- about five times the amount of information that can be stored on a DVD
Each Blu-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 0.6-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
Woking of blu-ray:
The Blu-ray disc overcomes DVD-reading issues by placing the data on top of a 1.1-mm-thick 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.
Source: Blu-ray Disc Association
The design of the Blu-ray discs saves on manufacturing costs. Traditional DVDs are built by injection molding the two 0.6-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.
Blu-ray discs only do the injection-molding process on a single 1.1-mm disc, which reduces cost. That savings balances out the cost of adding the protective layer, so the end price is no more than the price of a regular DVD.