Technology
Presented By:
Shyam K
History of Compact Digital Media
1980: The first Compact Disk player is produced by Sony/Phillips.
1982: The first Compact Disk is manufactured for sale, Billy Joel’s “52nd Street”
1984: First portable Compact Disk players enter the market followed by car CD players shortly after.
1985: Sony/Philips announce the standard for compact disc storage of computer data, the CD-ROM
1987: Video CD format is designed.
1991: CD-R (Compact Disk Recordable) technology is introduced as a new storage technology.
1996: Digital Versatile Disk(DVD) technology is introduced
1997: DVD’s and DVD players begin to enter the market
1998: DVD Recordable systems invented and begin to enter the market
2000: DVD movies become mainstream and replace analog VHS as the format of choice.
DVD is Born!
 Space limitations plagued CD’s to a life only in the music
market
 Video producers could not fit full length movies on a CD.
 The goal of DVD was to create a “vastly increased
capacity, with the ability to feature an entire movie in
high-quality digital video on a single side of a disc.”
 They also wanted...Brighter colors, sharper pictures, and
outstanding audio quality
 The goal was a 4.7 gigabyte capacity with the ability to
hold hours of full motion video and sound
Obviously they did it… But How?
• DVD uses Smaller pit
and land dimensions,
therefore the laser
must me exponentially
more accurate than
with CD’s.
• More closely-spaced
tracks, called "track
pitch"
• A shorter-wavelength
laser
The Wavelength Issue:
•DVD Players and DVD-ROM drives use a laser that
emits high intensity red light at 650 and 635nm vs the
780 nanometers for CD technology
•These shorter wavelengths are better at reading the
smaller, densely packed together pits and lands.
•The laser assembly has been re-engineered to produce a
more tightly focused laser beam
How Many Layers Would You Like?
As an interesting consequence of using the new lasers and the new
DVD design elements, they found that multiple sides and layers
could be stacked onto a single DVD disk. A total of 4 configurations
were found to be viable:
 Single Side, Single Layer
 Single Side, Dual Layer
 Double Side, Single Layer
 Double Side, Dual Layer
Layers..
CD versus DVD
Who has the advantage here?
• Both discs are the same physical size (120 mm diameter & 1.2 mm thickness,
which makes CDs compatible with DVD players.
• Both discs are made with the same basic technology and production processes
• Both technologies read discs in the same manner
• DVD software can be replicated from existing CD production facilities
However DVD has some tricks up its sleeves….
• DVD can hold exponentially more data than a CD can
• DVD has Higher density data storage where smaller pits and smaller tracks in
DVDs provide seven times storage alone compared to CDs
• DVD has less overhead & more area because the DVD’s error-correction scheme
is more efficient and requires less storage space that can be used for other
information
• DVD can have Multi-layer storage whereas CD stores data on one layer on one
side of disc. DVD can store up to two layers on up to two sides of the disc, which
allows up to 4X the storage amount
CD versus DVD
Construction of a DVD
DVD construction is similar to traditional CD-ROM construction with a few added
steps, and a much higher degree of manufacturing tolerance required.
Physical formatting
Analog signal is converted to a digital signal and compressed using DVD
compression standards, then stored for transfer onto the DVD.
Construction of a DVD.. Cont..
Glass mastering.
A glass base is coated with light-sensitive
photoresist, which is then developed in a
sodium silicate solution, using a laser to
implant the digital signal
Metallization.
Nickel is evaporated on the surface
of the master, providing a
conductive layer for the
electroplating phase.
Construction of a DVD.. Cont..
Electroplating.
A wet process in which the master is
bathed in nickel sulfamate and a
stamper is applied to create the
pattern required for multiple disc
replication.
Molding.
The previously created master is
used as a base, giving a pattern
pressed onto an injection molded
polycarbonate substrate.
Construction of a DVD.. Cont..
Sputtering.
Similar to semiconductor
sputtering, a metal layer is
formed on the surface, aluminum
for single layer, gold or silicon
carbide for dual layer discs.
Bonding.
Multiple layers are bonded
together using either hot melt or
ultraviolet processes. This
bonding requires extreme
precision to prevent the DVD
from becoming unbalanced
DVD Components
Optical system
The optical system is made up of a laser, photodetector, prism, mirrors, and
lenses. The laser and photodetector are installed on a plastic housing, and the
other components are placed in specific places. Great care is taken in the
positioning of each of these pieces because without proper alignment, the
system will not perform properly.
Disc drive mechanism
The optical system is attached to the motor that will drive it. This in turn is
connected to the other principle parts of the disk drive including the loading
tray and the spindle motor. Other gears and belts are attached and the entire
assembly is placed in the main body.
Printed Circuit Board
The electronic components of the DVD machine are sophisticated and use the
latest in electronic processing technology. The circuit board is produced much
like that of other electronic equipment.
DVD Components
Inside DVD player
DVD Working
• The pits and bumps in the DVD are hit by the laser from the optical
mechanism of the DVD player. This laser will be reflected differently
according to the change of pits and bumps.
• Though the laser hits a single spot, the DVD moves in a circular motion
so that the entire area is covered. Mirrors are also used to change the
spot.
• These reflected laser beams are then collected by a light sensor (eg.
photo-detector) which converts the different signals into a binary code.
• In short, the optical system helps in converting the data from the DVD
into a digital code.
• The binary signal is then sent to a Digital to Analog converter which will
be setup in the PCB. Thus the corresponding analog signal of the DVD is
obtained.
• The PCB also has amplifiers which amplify the signal and then sends it
to the graphic and audio systems of the computer/TV. Thus, the
corresponding audio/video signal is obtained.
DVD Working
DVD Working
DVD Application
DVD-ROM. High-capacity, high-throughput, read-only optical disc that can be
used as a general-purpose computer storage device. This application is currently
the most prevalent, with disc storage ranging from 4.7 to 17.0 GB, depending
on format.
DVD-Video. High capacity, high throughput read-only optical disc that can be
used for the interactive playback of high quality video, audio and graphic
content. This application, similarly uses disc storage ranging from 4.7 to 17.0
GB, depending on the format.
DVD-Audio. Similar to the DVD-Video, differing only in the compression and
storage of audio, rather than video.
DVD-R. High capacity, high throughput, write once, optical disc used as a
general-purpose computer storage device. This application currently is
formatted to hold 3.8 GB of storage per side, although current advances promise
to achieve 4.7 GB per side.
DVD-RAM. High capacity, high throughput, read-write, used as a highly
versatile storage medium for computers and other devices. This application
currently uses its own format, allowing 2.6 GB of storage per side.
HD DVD / BLU-RAY
 In 2006, two new formats called HD DVD and Blu-ray Disc were released
as the successor to DVD.
 HD DVD competed unsuccessfully with Blu-ray Disc in the format war of
2006–2008.
 A dual layer HD DVD can store up to 30GB
 And a dual layer Blu-ray disc can hold up to 50GB.
BLU-RAY Technology
•
•
•
•
Name derived from the blue-violet laser used to read and write data.
Developed by the Blu-ray Disc Association with more than 180 members.
Major Supporters – Dell, Sony, LG
Because Blu-ray uses a blue laser(405 nanometers) instead of a red
laser(650 nanometers) this allows the data tracks on the disc to be very
compact.
• This allows for more than twice as small pits as on a DVD.
HD DVD Technology
• Name obviously comes from the term High Definition
• Developed by Toshiba and NEC
• HD DVD uses close to the same blue laser that the Blu-ray disc does.
It is also 405 nanometers wide.
• Thus allows for data to be greatly compressed
DVD vs BLU-RAY Technology
DVD vs HD DVD Technology
The Future of DVD
 Optical storage technologies has been developing fast, DVD
and Blu-ray technology are the most commonly used optical
storage technologies in our daily life.
 Recently HD DVD and Blu-ray has become the important role
in the optical storage field.
 Videotapes, which once dominated the market, are a thing of
the past so surely it is inevitable that the DVD will face the
same future
 Technological progression in the form of online streaming and
Blu-ray ultimately means the end of the road is imminent for
the DVD.
 But in the not so distant future DVDs, and even Blu-ray will
eventually reach a dead end….
The End