Novel inventions such as MSR, MAMMOS, DWDD are realized as commercial products.Complicated optical head (Polarization detection).Rotation of linear polarization is converted to the electrical signal.Recording: Thermomagnetic (Curie point)recording.
Amorphousdiskmark download Pc#
Protective layer Reflecting layer Pit PC substrate CD Protective layer Reflecting layer Pre-groove Organic dye layer CD-R Recorded mark PC substrate protective layer Dye layer deformation of substrate PC substrate laser beam CD-R ĭVD-ROM DVD-R DVD-RAM DVD-RW DVD+RW capacity (GB) 4.7 / 9.4 2層8.54 3.95 / 7.9 4.7 / 9.4 4.7/9.4 4.7/9.4 Form disk disk cartridge disk disk Mark formation/ Material/ reflectivity pit formation 1L R=45-85 2L R=18-30 thermal deform organic dye R=45-85% phase change GeSbTe alloy R=18-30% phase change AgInSbTe alloy R=18-30% phase change AgInSbTe alloy R=18-30% wavelength nm lens NA 650/635 0.6 650/635 0.6 650 0.6 638/650 0.6 650 0.65 shortest mark size 1層:0.4 2層:0.44 0.4 0.41-0.43 0.4 0.4 track width 0.74 0.8 Wobbled Land pre-bit 0.74Wobbled L/G 0.74 Wobbled Land pre-bit 0.74 HF Wobbled groove Cyclability - - 105 103-104 103-104 DVD Family G(r): Probability to find a neighboring atom at a distance of r.DRPHS (dense random packing of hard spheres) can explain RDF (radial distribution function).Random metallic alloy, chalcogenide glass, tetrahedral system, oxide glass.Metastable state introduced by rapid cooling of liquid.Atomic arrangement of liquid is frozen.without LRO (long range order) but with SRO (short range order).Slow cooling below Tmcrystalline→high reflectivity Ĭrystalline and amorphous recorded: amorphous Initial:crystalline R: high R: low Record Erase laser spot recorded mark.Rapid cooling:amorphous→low reflectivity.Temperature temperature Rapid cool Slow cool melting point melting point crystalli-zation point crystalli-zation point time time Energy amorphous activation energy low reflectivity crystalline high reflectivity Recording and erasing Low level:Heating above Tcr→slow cool→crystalline DVD-RAM: GeSbTe based alloy DVD±RW: Ag-InSbTe based alloy.High level :Heating above Tm→rapid cool→amorphous.Erasing is done by heating to Tcr(400 C) to crystallize. Recording is performed by heating above the melting point Tm (600C) followed by quenching to amorphous state. Rewritable:As grown amorphous state is initialized to crystalline state by annealing.UV coat Printed surface Protective layers Reflection layer Recording layer Substrate Land CD-RW Optical pickup Objective lens Tracking Servo Focusing Servo Quarter wave-plate Collimating lens Grating Polarization Beam Splitter Cylindrical lens Optical detector.Phase difference in reflectionπ:Destructive addition of reflected beams.λ=780nm →λ’=503nm (wavelength in the substrate).(2000.1) p.11 Increase of Areal Density in Optical Disks Aiming at 100 Gb/in2 using near-field technique.Hole-burning memory: Local structure change.Holographic memory: Photorefractive effect.Magnetic phase change between ferromagnetic and paramagnetic states.Phase change between ordered and disordered states.Physical phenomena used in optical disk technology Holographic memory, Hole-burning memory.Magneto-optical: MO, GIGAMO, MD, Hi-MD, AS-MO, iD-Photo.Phase change CD-RW, DVD-RAM, DVD-RW, DVD+RW, BD, HD-DVD.
Direct read after write (Write once type).Α spot sized Spot size at the focal point Different physical phenomena are used for recording of the signal on optical disks.There are three categories of optical storage, i.e., read-only type, write-once type and rewritable type.