Overview of Optical Recording Technology- Current Status and Near Term Projections

Transcription

1 Overview of Optical Recording Technology- Current Status and Near Term Projections Koichi Sadashige Sadashige Associates 15 Amherst Rd, Voorhees NJ Phone: , FAX: Presented at the 8 th Goddard Conference on Mass Storage Systems & Technologies/17 th IEEE Symposium on Mass Storage Systems 4/15/00 8:34:11 PM K Sadashige 1

2 Optical Recording Characteristics Recording Type: Physical Height Change (Pit on Land) Recording Method: Injection molding Reading Method: Optical Path interference Products: CD, DVD, CD-ROM ¼λ 4/15/00 8:34:11 PM K Sadashige 2

3 Optical Recording Characteristics 2 Recording Type: Magnetization Reversal Recording Method: Spot temperature elevation near Curie point Reading Method: Kerr Angle differentiation Products: MO (Magneto-optical) 4/15/00 8:34:11 PM K Sadashige 3

4 Optical Recording Characteristics 3 & 4 Recording Type 3. State Change 4. Polymer Dye characteris tic change Recording Method 3. Pit temperature elevation 4. Pit temperature elevation Reading Method 3. Reflectivity differentiation 4. Reflectivity differentiation Products 3. PC (phase change) DVD-RAM 4. CD-R DVD-R 3 4 4/15/00 8:34:11 PM K Sadashige 4

5 Areal Density of Data Storage System Hard disk drive Product Corsair Microdrive 1999 Demo TPI ,238 19,000 67,300 Kbits/in Mb/in ,035 35,300 µm 2 /bit /15/00 8:34:11 PM K Sadashige 5

6 Areal Density of Data Storage System Magnetic Tape Product 3480 ID-1 DVC (LP) DLT-7 TPI , Kbits/in Mb/in µm 2 /bit /15/00 8:34:11 PM K Sadashige 6

7 Areal Density of Data Storage System Optical Disk Product CD DVD- RAM 2.6 GB DVD- RAM 4.7 GB Next Gen 15~25 GB TPI 15,875 34,300 41,300 85,000 Kbits/in Mb/in ,130 3,745 10,000 µm 2 /bit /15/00 8:34:11 PM K Sadashige 7

8 D f number = F/D Numerical aperture, NA = sin θ θ NA = D / 2 ( F + D / 4) / F Spot size = d d = σλ/na d Where λ = wavelength of laser σ== factor determined by beam energy distribution 4/15/00 8:34:11 PM K Sadashige 8

9 120 mm 50 mm 15 mm Structure of Compact Disc 116 mm Data Area Pit width 0.5 µm Pit size to µm Track pitch 1.6 µm 4/15/00 8:34:11 PM K Sadashige 9

10 λ/4 Compact Disc Structure Printing Ink Protective Lacquer Layer 5 µm 30 µm Metalized Reflective coating 1.2 mm 90% reflection from land 20% reflection from pit 4/15/00 8:34:11 PM K Sadashige 10

11 120 mm 50 mm 15 mm Structure of DVD 116 mm Data Area Pit width 0.5 µm Pit size 0.4 to 2.13 µm Track pitch 0.74 µm 4/15/00 8:34:11 PM K Sadashige 11

12 DVD Disc Structure Single Layer Disc (4.7 GB) λ/4 1.2 mm Data Reading 4/15/00 8:34:11 PM K Sadashige 12

13 DVD Disc Structure Metalized Reflective Layer Double Layer Disc (8.5 GB) Semitransparent Reflective Layer 1.2 mm λ/4 Front Layer Reading Inside Layer Reading 4/15/00 8:34:11 PM K Sadashige 13

14 Recording Process (Phase Change) Erased state Crystalline phase Recorded state Amorphous phase Melting temperature 10 8~10 C/sec Recording Crystallization temperature Room temperature Crystallization time depends on alloy Time Rapid cooling by laser spot removal Erasure - crystallization Crystallization temperature Room temperature 50 nsec Data rate limited by crystallization time characteristic of the alloy Current status MB/sec Near term objective MB/sec 14

15 Single layer DVD-RAM disc structure Polycarbonate substrate Upper protection layer ZnS-SiO SiO 2 Recording layer: TeSbGe Lower protection layer ZnS-SiO SiO 2 Reflection layer: Al alloy UV hardened plastic layer Auto track finding system Track wobbled from track center line with period equal to 1/232 of sector length 4/15/00 8:34:11 PM K Sadashige 15

16 DVD-RAM Disc (Version 1.0) 2.6 GB user data per surface Defect management area User Zone 23 (40 sectors) User Zone 0 (17 sectors) Defect management area Non-recordable area containing disc and format information 24 user zones Reserved area for defect management User data area Data sector Prerecorded sector header 4/15/00 8:34:11 PM K Sadashige 16

17 Mark and Mark Edge Recording RZ NRZ NRZI Mark Recording Mark Edge Recording Mark Edge Inverted 4/15/00 8:34:11 PM K Sadashige 17

18 Possible Dual Layer DVD-RAM Disc Configuration Polycarbonate substrate ZnS-SiO 2 Protection Te.Sb.Ge Recording ZnS-SiO 2 Protection Bonding Thinner recording layer Ge-N crystallization accel Al Alloy semitransparent reflective layer ZnS-SiO 2 Protection Te.Sb.Ge Recording ZnS-SiO 2 Protection Polycarbonate substrate Thinner recording layer Ge-N crystallization accel Al Alloy full reflectivity layer UV cured polymer 4/15/00 8:34:11 PM K Sadashige 18

19 Areal Recording Density of Representative Products (1999) Areal Density Bit Cell (µm) Product TPI Kbpi Mb/mm 2 Width Length Area DVD-RAM (V 2.0) IBM HDD Microdrive DDS DLT /15/00 8:34:11 PM K Sadashige 19

20 2003 (67000,520) 3480 (1984) (40, 49.4) Linear Tape DLT-7 (1990) (590, 123) ID-1 (1985) (655,51) DDS-3 (1999) (2820, 153) Helical scan Tape HDD 1990 (2240,59) 1999 (19000,265) 2003 (NG) (120, 85000) 2000 (DVD-RAM) (41300, 91) Optical (CD, DVD) 1982 (15900,30) 1980 (800,15) 4/15/00 8:34:11 PM K Sadashige 20

21 Bit cell size and Aspect Ratio circa DLT DDS-3 DVD-RAM V Note: all dimensions are in µm HDD /15/00 8:34:11 PM K Sadashige 21

22 DVD-RAM Characteristics Version 1.0 Version 2.0 Dual Layer Proposal Future Year of introduction Capacity per surface, GB ~18 Double sided media Yes Yes Laser l nm Objective lens NA ~0.85 Track pitch mm Minimum mark length mm Max Transfer rate, MB/s ~9 4/15/00 8:34:11 PM K Sadashige 22

23 DVD-RAM Characteristics (continued) Common Characteristics Disc: diameter = 120 mm, thickness = 1.2 mm Single sided disc: in protection jacket. Disc can be removed from f special jacket. Double sided disc: in protection jacket. Disc not removable from jacket. Disc must be flipped and reinserted in order to write to/read from second side. Dual layer disc: Both layers can be written to and read from the side the layers are on. 4/15/00 8:34:11 PM K Sadashige 23