chapter 9 - future development

8/8/2019 Chapter 9 - Future Development

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Development of High Density

Optical Storage Media

2002. 04. 26


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Outline

Development History of Optical Storage

Media

Classification for Optical Storage Media

Principles of Optical Storage Technology

High Density Optical Storage Media

Conclusions


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Development History of Optical Storage Disc

1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

CD-DA

CD-RO M

CD-RW

Photo CD

Video CD

CD-R

CD-MO

CD-I

DVD-RAM 2..6GB

DVD ROM & Video

DVDRAM/R/RW 4.7GB

DVD Audio

DVR 22.5GB

DVD+R /RW 4.7GB


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Classification for Optical Storage Disc

Read-Only

CD-DA

CD-ROM

VCD

DVD-VideoDVD-ROMDVD-Audio

RecordableCD-RDVD-R RewritableCD-RWDVD-RAMDVD-

RWDVD+RWDVR


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Read-Only Disc Structure

Mastering Replication metallizationLacquering ( bonding ) Printing


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Recordable Disc Structure

Mastering Replication Dye coating

metallization Lacquering Printing


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Recordable Disc Structure

Mastering Replication Dye coating

metallization Bonding Printing


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Mastering Replication ZnS-SiO2/AgInTeSb

/ZnS-SiO2/Al-Ti Sputtering Lacquering Printing

Rewritable Disc Structure


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Rewritable Disc Structure


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Pick-up Head


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Optical Path of Pick-up Head


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Read for Read-Only Disc


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00000100010000000100000000010000

Land Pit Land Pit Land

Read for Read-Only Disc


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WriteErase and Read for Rewritable DiscInitialized

Active Layer Written Bit

Temp.

Tm

Tg

Write Read Erase

Time


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Multi-Media Applications

1997 2000 2005 2010 2015

4.7 GB 15GB 36GB 100GB 1TB

VideoROM2 hrs

VideoRAM2 hrs

HDTV

4 hrs

3-D

Video

Interactive

3-D Video

Capacity

Transfer Rate

eek Time

20 MB/s 50-100 MB/s 100-250 MB/s 1 GB/s

30 ms 10-20 ms 5-10 ms 1-2 ms


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How to Increase Recording Density

Spot Size Reduction

Volumetric

StorageDataFormat

Disc Fabrication

High DensityOptical

Storage Media

Multi-layer

Photo-induced

HolographicECC

Multi-level

Modulation

Short High NA Near-Field Super Resolution

High-tech mastering L/G and Deep Groove


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How to Increase Recording Density Reduce Laser Spot Size

Short Wavelength=400nmHigh Numerical ApertureNA=0.8

Solid Immersion Lens (SLI) : To Increase Numerical

Aperture

Super-RENS

Increase Coding EfficiencyMulti-level Coding Multiple-layer StructureMulti-layer Recording Volumetric Recording Holographic Optical Recording


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DVR ( = 400 nm NA = 0.85 )

Blue Laser

High NA double-Lens

Assemble

0.1mm Hard Cover Layer

Single layer capacity 22.5GB


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DVR ( = 400 nm NA = 0.85 )


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Solid Immersion Lens

Excess theoretical NA limit

1

Air Gap10 100 nm

Near Field Recording

Laser spot size 100 nm

Single layer capacity 100Gdisc

f

NA=0.55~0.8

n1=1.45~1.9 h <

SIL


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SUPER-RENS

Optical Super-Resolution

Near Field Structure

Can read pit length < 60 nm

Single layer capacity 200GB


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SUPER-RENS


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Diffraction-Limit

Spot size 0.6 /NA


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SUPER RENS


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SUPER-RENS

Requirements for mask layer

Fast Response

High sensitivity

Large transmittance change

High stability

SUPER RENS


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SUPER-RENS

Transmitted Type Scattering Type

M lti l l


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Multi-level

Multi-level is to improve the coding efficiency of

recording bits to increase recording density

PPMPit Position ModulationPWMPit Width Modulati


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Multi Level Rewritable


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Multi-Level Rewritable

Matsushita - Mark Radial Width Mod

Multiple level Reflection Modulation


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Multiple-level Reflection Modulation

Terabyte Optical Storage


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Terabyte Optical Storage

3D Storage3D3D StorageStorage

Multi-function Volumeric optical disks Holographic Memory

Fluorescent Multilayer Disc FMD


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Fluorescent Multilayer DiscFMD

US Constellation 3D

(C3D) Company

06/200040GBAnalogue Video Disc

10/2000 50GB DigitalVideo Disc

Future > 100GB



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Fluorescent Multilayer DiscFMD Advantages

Every layer is transparent. There is no reflectiveinterface between layers.

The exciting radiation energy can be achieved byabsorption of 1% incident light.

The exciting fluorescent signals wont be absorbed byother fluorescent materials.



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Fluorescent Multilayer DiscFMD With larger tolerance for the imperfection of storage

media as well as disc drive. Compatible with the existing CD and DVD systems.

Read and write can be performed simultaneously. Data

transfer rate is much higher than that of single layer

disc.


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650nm

50nm


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Holographic Optical Recording


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g p p g

High data transfer rate Rewritable Disc


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g

Requirements for phase change materials

High Photo-sensitivity

Large optical contrast between crystalline and

amorphous phases High thermal stability

High structural stability

Fast re-crystallization rate

How to increase re-crystallization rate ?


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y

Optimum recording layer

thickness

thickness ~ 30 nm t (nucleation) ~ 17 ns

CET ~ 38 ns

Crystallization acceleration lay

SiC or GeN

t (nucleation) ~ 14 ns

CET ~ 27 ns

GeSbTe + O2



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y



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y

780

0.50

658

0.60

658

0.85

400

0.85

AgInSbTe

Ge2Sb2Te5

0.0 0.4 0.8 1.2 1.6 2.0

Reciprocal Spot Diameter ( m-1 )

MaximumUser

DataRate(Mbit/s)

0

10

20

30

40

50

60

70

80

Fast Growth Materials


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0 10 20 30 40 50 60 70 80 90 100

100

90

80

70

60

50

40

30

0

10

20

90

100

80

70

60

50

40

30

20

10

0

(at%) Sb (at%)

Ge (at%)

Conclusions


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Higher recording density Larger

capacity and Faster data transfer rate

is the trend in the development of optical

storage medium !!

Thank you !!

chapter 9 - future development

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