BLU-RAY DISC by xiangpeng


                          BLU-RAY DISC
                             PRESENTED BY

A current, single-sided, standard DVD           more storage. As TV sets and movie
can hold 4.7 GB (gigabytes) of                  studios make the move to high definition
Information. That's about the size of an        consumers are going to need playback
average two-hour, standard-definition           systems with a lot more storage capacity.
movie with a few extra features. But a
high-definition movie, which has a much         Blu-ray is the next-generation digital
clearer image (see how Digital                  video disc. It can record, store and play
Television Works), takes up about five          back high definition video and digital
times more bandwidth and therefore              audio, as well as computer data.
requires a disc with about five times

The advantage to BIu-ray is the sheer                 video or about 13 hours of standard
amount of information it can hold:                    video.

   A single-layer BIu-ray disc, which is          A double-layer Blu-ray disc can
    roughly the same size as a DVD, can               store up to 54 GB, enough to hold
    hold up to 27 GB of data that's more              about 4.5 hours of high-definition
    than two hours of high-definition                 video or more than 20 hours of
                                                      standard video.

   Record High-Definition Television                Edit programs recorded on the disc.
    (HDTV) without any quality loss.                 Automatically search for an empty
   Instantly skip to any spot on the disc.           space on the disc to avoid
   Record      one     program      while            recording over a program.
    watching another on the disc                     Access the web to down load
   Create play lists.                                subtitles and other extra features

Discs store digitally encoded video and           DVD. The more data that is contained on
audio information in pits spiral                  a disc, the smaller and more closely
grooves that run from the center of the           packed the pits must be. The smaller the
disc to its edges. A laser reads the other        pita (and therefore the bumps), the more
side of these pits the bumps to play the          precise the reading laser must be.
movie or program that is stored on the

Unlike current DVD’s, which use a red            DVD.Plus, Blue-ray has reduced the
laser to read and write data, Blu-ray uses       track pitch from 0.74 microns to 0.32
a blue laser (which is where the format          microns. The smaller pits, smaller beam
gets its name). A blue laser has a shorter       and shorter track pitch together enable a
wavelength (405 nanometers) than a red           single-layer Blu-ray disc to hold more
laser (650 nano meters). The smaller             than 25GB of information about five
beam focuses more precisely, enabling it         times the amount of information that can
to read information recorded in pits that        be stores on a DVD.
are not only 0.15 microns long this is
more than twice as small as the pits on a

Each BIu-ray disc is about the same              separate beams. If the beam is split too
thickness (1.2 millimeters) as a DVD.            widely, the disc cannot be read. Also, if
But the two types of discs store data            the DVD surface is not exactly flat, and
differently. In a DVD, the data is               is therefore not exactly perpendicular to
sandwiched between two polycarbonate             the beam, it can lead to a problem
layers, each O.6-mm thick. Having a              known as disc tilt, in which the laser
polycarbonate layer on top of the data           beam is distorted. All of these issues
can     cause    a    problem     called         lead to a very involved manufacturing
birefringence, in which the substrate            process.
layer refracts the laser light into two


Will Blu-ray replace previous DVDs?              release of video in both formats on a
Its manufactures hope so. In     the             single disc. But Blu-ray is not alone in
meantime JVC has developed a Blu-ray             the marketplace. A few other formats are
/DVD combo disc with an approximate              competeting for a share of DVD market.
33.5GB capacity, allowing for the

The other big player is HD_DVD,                 hold 20 GB of data; a double –layer
also called AOD(Advanced Optical                disc can hold 30 GB(that’s compared
Disc), which DVD and can therefore              to 27 GB and 50 GB for Blu-ray).
be manufactured with the same                   The read-only versions hold slightly less
equipment, saving      on    costs. The         data. Also, HD_DVD doesn’t offer the
disadvantage is that it can’t match the         interactive capabilities of Blu-ray ,
storage capacity of Blu-ray. A                  although it will probably be less
rewritable, single layer HD_DVD can             expensive than its competitor
Blu-ray recorders are already available         definition ( which is expected to
in Japan, where more consumers have             happen by late 2005 or 2006), BIu-
access to HDTV than in the United               ray movies and TV shows on disc
States. Outside of Japan, once more             should become widely available. But
TV sets come equipped with a high-              the format is already available for
definition tuner and more films and             home       recording,       professional
television shows are produced in high-          recording and data storage.

Another important factor is cost. Just as
with most new technologies, Blu-ray             Even when the new video standard
equipment will be pricey at first. In           begins to replace current technologies,
2003, Sony released its first BIu-ray           consumers won't have to throw away
recorder in Japan with a price tag of           their DVDs, but they will need to
around $3,000. The price is expected to         invest in a new player. The industry
drop as the format gains popularity. Blu-       is planning to market backward-
ray discs may also be initially more            compatible drives with both blue and
expensive than today's DVDs, but                red lasers, which will be able to play
once demand grows and they can be               traditional DVDs and CDs as well as
mass-produced, manufacturers say the            Blu-ray discs.
price will drop to within 10 percent
of the price of current DVDs.

The Play station 3 will be the first Blu-       Sony has announced that the PlayStation
ray accessable player.                          3 will be shipped with a Blu-Ray drive,
                                                but possibly just a read-only one. Sony's
The first BIu-Ray recorder was unveiled         machine will also support BD-ROM pre-
by Sony and was introduced to the               recorded media, which are expected to
Japanese market. JVC and Samsung                be available in early 2006.
Electronics announced Blu-ray based
products at IFA in Berlin, Germany.

Blu-ray drives currently in production          prototypes with a 108 Mbit/s transfer
can transfer approximately 36 Mbit/s (54        rate are in development. Rates of 8x or
Mbit/s for BD-ROM), but 2x speed                more are planned for the future.

Hewlett Packard has announced plans to          debut a Blu-ray computer drive in the
sell Blu-ray-equipped desktop PCs and           second half of 2005, but it was also
laptops. In December 2005, HP                   delayed. On March 10, 2005 Apple
announced that they would also be               Computer joined the Blu-ray Disc
supporting the rival HD DVD                     Association.
technology. Philips was scheduled to
Blu-ray disc has been a consistent              works to develop a disc with twice
road map to emerging disc                       that amount of storage.
technologies. Blue-ray can store up to          It’s very likely that the technology
54 GB, enough to hold about 4.5                 will be adopted as the next
hours of high -definition video or              generation optical disc format for PC
more than 20 hours of standard video.           data storage and replace technologies
And there are even plans in the

such as DVD+-R, DVD+-RW, and               DVD-RAM.
1. Complete Guide to Digital Audio                By—Chris Middleton.
2. The Digital Bits Insider Guide to DVD          By—Bill Hunt
3. DVD Demystified                                By – Jim Taylor



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