Presented By:Presented By:

Shyam KShyam K

TechnologyTechnology

History of Compact Digital MediaHistory 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!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?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: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?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..Layers..

CD versus DVDCD versus DVDWho has the advantage here?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….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 DVDCD versus DVD

Construction of a DVDConstruction of a DVDDVD construction is similar to traditional CD-ROM construction with a few added steps, and a much higher degree of manufacturing tolerance required.

Physical formattingPhysical 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..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..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..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 ComponentsDVD ComponentsOptical systemThe 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 mechanismThe 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 BoardThe 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 ComponentsDVD Components

Inside DVD playerInside DVD player

DVD WorkingDVD 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 WorkingDVD Working

DVD WorkingDVD Working

DVD ApplicationDVD ApplicationDVD-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-RAYHD 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 TechnologyBLU-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 TechnologyHD 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 TechnologyDVD vs BLU-RAY Technology

DVD vs HD DVD TechnologyDVD vs HD DVD Technology

The Future of DVDThe Future of DVD

The End