BLU-RAY DISC

By : Ankit Gupta

CD DVD

BLU-RAY

INTRODUCTIONBlu-ray, also known as Blu-ray Disc (BD) is

the name of a next-generation optical disc format. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data.

The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc.

FoundationBlu-ray disc (BD) is appropriately named after

the blue laser used to write the dataThe first blue laser was developed in 1996 by

Shuji Nakamura (Nichia Corporation)In 2002, an alliance was formed, called the

Blu-ray Disc Association, including the likes of Sony, Samsung, Sharp, Hewlett-Packard, and Royal Phillips.

It has One layer, Two layer, Three layer, Four layer

Five layer, Six layer.

Variations and SizesA single-layer Blu-ray disc (BD) has enough

storage capacity (25GB) for approximately two hours of high-definition video with audio.

A dual-layer (50GB) BD can hold enough data for approximately four hours of HD video.

TDK recently announced that they have created a working Blu-ray disc capable of holding 200GB of data (six 33GB data layers).

HISTORY

                                                                                    

Laser and optics Blu-ray systems use a blue-violet laser

operating at a wavelength of 405 nm, similar to the one used for HD DVD, to read and write data. Conventional DVDs and CDs use red and infrared lasers at 650 nm and 780 nm respectively.

Blu-ray has two types BD-R and BD-RE with price

$19.99 and $24.99 for 25GB and $47.99 and $59.99 for 50GB respectively.

Why Blue Lasers?High-definition TV provides six times more

picture information than standard-definition TV

More bits per second requiredMore gigabytes per disc required

1920 x 1080 x 30 = 62 million pixels/second

720 x 480 x 30 = 10 million pixels/secondHDTV

SDTV

Disc CharacteristicsSingle layer: 25 GB

Dual layer: 50 GBDiameter: 120 mmThickness: 1.2 mmCenter hole

diameter: 15 mmUses GaN laser of

wavelength 400 nmThe smaller laser,

compared to the DVD and CD, keeps the process more efficient (~5 mW)

Courtesy Blu-ray Disc Founders “Blu-ray Disc Format White Paper”

Hard-coating technologyIn January 2004 was

introduced a clear polymer coating that gives Blu-ray Discs unprecedented scratch resistance. The coating was developed by TDK Corporation and is called "Durabis". It allows BDs to be cleaned safely with only a tissue.

Blu-ray vs DVD capacity

CD vs DVD vs Blu-ray writing

CompatibilityThis issue has introduced a competitor, the HD-

DVD, that based its technology around being compatible with the DVD

Recently the BDA has developed recorders that are BD/DVD/CD compatible

JVC has advanced the BD by developing a BD/DVD combo disc that stores both DVD and BD data. It is composed of two DVD layers and a third BD layer storing 33.5 GB total

Blu-ray Advantages 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 discEdit or reorder programs recorded on the

disc Automatically search for an empty space on

the disc

FutureExpect the BD to become more prevalent

once the HDTV market establishes its presence

Audio and video will reach higher qualities with larger storage space

Look for BD with more than two layers as the technology is further refined

ConclusionBoth DVD and BD would most likely co-exist

for quiet some time until HDTVs become more widespread.

Thank you