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( HVD )

HOLOGRAPHIC VERSATILE DISC

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CONTENTS

1. INTRODUCTION

2. UNDERLYING TECHNOLOGY-

HOLOGRAPHY

3. RECORDING DATA

4. READING DATA

5. HVD- STRUCTURE

6. COMPARISON

7. TYPES : WORM & RW8. REFERENCES

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INTRODUCTION

Next-Next Generation Technology

Scientist J. V. Heerden came up with this idea in 1960

Media type : Ultra-high density optical disc

Encoding : MPEG-2, MPEG-4 AVC (H.264), and VC-1 Capacity theoretically up to 3.9 TB

Developed by HSD Forum

Usage :Data storage,

:High-definition video & the possibility of ultra high

definition video

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FEATURES

Data transfer rate : 1gbps.

The technology permits over 10 kilobits of data to be written and

read in parallel with a single flash.

Most optical storage devices, such as a standard CD saves one bit

per pulse. HVDs manage to store 60,000 bits per pulse in the same

place.

1 HVD = 5800 CDs = 830 DVD =160 BLU-RAY

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HOLOGRAPHY VS PHOTOGRAPHY

Black and white photograph

Contains Intensity distribution

Color photograph Intensity and wavelength

Hologram

Intensity, phase, and sometimes wavelength

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HOLOGRAPHY

INVENTED BY

SCIENTIST

GABOR IN 1947.

CONTAINS

INFORMATION

ABOUT AMPLITUDE

AND PHASE OF

OBJECT WAVE.

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RECORDING DATA

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SPATIAL LIGHT MODULATOR (SLM)

Translates electronic data (0's and 1's) into

optical pattern of light and dark pixels.

Data is arranged in an array similar to acheckerboard of usually 1M (million) bits.

By varying the angle of the reference

beam,wavelength or media position, manyholograms can be stored in the same

volume of storage material.

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READING DATA

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HVD TECHNOLOGY

HVD uses a technology called 'collinear holography,'

Two laser rays, one blue-green and one red are used.

The role of the blue-green laser is to read the data encoded in theform of laser interference fringes from the holographic layer.

The red laser serves the purpose of a reference beam and also toread the servo info from the aluminum layer.

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HVD STRUCTURE

1. Green writing/reading laser (532 nm)

2. Red positioning/addressing laser (650

nm)

3. Hologram (data)

4. Polycarbon layer

5. Photopolymeric layer (data-containing

layer)

6. Distance layers

7. Dichroic layer (reflecting green light)

8. Aluminium reflective layer (reflecting

red light)9. Transparent base

P. PIT

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COMPARISON

Parameters DVD BLU-RAY HVDcapacity 4.7 GB 25 GB 3.9 TB

Laser wave length 650 nm

(red)

405 nm

(blue)

532 nm(green)

Disc diameter 120 mm 120 mm 120 mm

Hard coating no yes yes

Data transfer rate(raw data)

11.08mbps

36 mbps 1 gbps

Data transfer rate(audio/video)

10.08mbps

54 mbps 1 gbps

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supports some irreversiblephotochemical reaction

triggered by the bright

regions of the optical

interference pattern

material diffuses from darker to

brighter regions so that short

monomer chains can bind together

to form long molecular chains

READ ONLY HVD

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READ/WRITE HVD

Uses inorganic photorefractive crystals.

Electrons get photo-excited at the

bright fringes diffuse or drift and

are re-trapped at a dark fringe.

Trapped charge can be rearranged

by later illumination, so it is possible

to erase recorded holograms.

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INTERESTING FACTS

It has been estimated that the books in the U.S. Library ofCongress, the largest library in the world , could be stored on

six HVDs.

The pictures of every landmass on Earth - like the ones shown inGoogle Earth - can be stored on two HVDs.

With MPEG4 ASP encoding, a HVD can hold anywhere between4,600-11,900 hours of video, which is enough for non-stopplaying for a year.

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COMPONENTS NEEDED FOR HVD READER

A blue-green argon laser

Beam splitters to spilt the laser beams

Mirrors to direct the laser beams

LCD panels (spatial light modulator) Lenses to focus the laser beams

Lithium-niobate crystals or photopolymers and

Charge-coupled device (CCD) cameras.

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PROTOTYPE PHOTO

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REFERENCES

Psaltis, D. Mok, F. Holographic memories. Scientific American

Encyclopedia of Optical Engineering