Digital Versatile Disc Research Articles

New optical storage formats developed in Taiwan

Two new optical storage formats, forward versatile disk (FVD) and blue high-definition digital versatile disk (HD-DVD), developed in Taiwan, are introduced. Some major technologies, including new modulation code and multilayer technology, are adopted in these formats to differentiate from current optical disc formats. For the further HD storage, several advanced technologies have been developed.

Invited Paper: 65.3: Invited Paper: Development of Image Quality Technology for Digital High Definition Plasma TV

The requirements for flat, thin TVs that have high image quality is increasing along with the spread of digital broadcasting services and the growing popularity of Digital Versatile Discs (DVDs). We have developed a new Digital High Definition Plasma TV to satisfy such demands. The new product features an improved-image-quality system which offers images of 3.62 billion colors and a maximum gray scale with 2048 levels. This new system incorporates innovative color creation technology to produce vivid images as well as proprietary motion pattern noise reduction technology to eliminate most of the motion picture anomalies and artifacts which are a continuing problem with Plasma Display Panel (PDP) TVs. This technology makes it possible to gain a 10% increase in brightness along with a 10% decrease in power consumption.

Radial fine seek control with fault protection in a digital versatile disc player

The paper proposes a fine seek servo controller for the digital versatile disk (DVD). The proposed control is an integration of a hybrid track position detector, a position accumulator, a position profile generator, a control finite state machine, an estimator, a defect detector, an RFRP signal compensator, a tracking servo equalizer (for both track-following and fine-seek) and a sled servo equalizer. The integration of these blocks enables a wider range of pull-in area for the servo to switch from track seeking to track following. The implementation results show that the proposed control achieves better performance over the conventional velocity control approach. The experimental results also demonstrated the ability of the control to effectively deal with disks with defects or fingerprints.

A Practical Laser Projector with New Illumination Optics for Reduction of Speckle Noise

We have developed illumination optics for image projection systems. It realizes uniform illumination and suppression of speckle and diffraction noises by using a diffuser and integrator optics. By optimizing the diffusing angle of the diffuser, optical power loss was less than 10%. A proto type of a laser projector with a red wide-stripe semiconductor laser and green and blue second-harmonic generation lasers was realized by using the developed illumination optics and twisted nematic liquid-crystal panels. Still images from a personal computer and video images from a digital versatile disk (DVD) player were displayed with the system and a wide colour gamut and smooth images without diffraction noise nor speckle noise were confirmed.

Surface Response Methodology for Write Strategy Optimisation in Optical Drives

A method for optimising write strategies in optical drives is proposed which is rigid and gives additional information on the reliability of the calculated results. In addition, the mathematical tool is used to examine the typical differences in write strategies with respect to parameter variations. As a test platform, digital versatile discs of the recordable type (DVD+R) are used at a speed of 8×. A comparison is made between the “castle” strategy and the blocked “thermally balanced” strategy. The differences are verified on three different discs. It appears that the write strategy determines the interdependence between write strategy parameters, while the disc brands differ in the optimum settings of the parameter. The presented method and experiments once more show the power of mathematical tools for understanding and applying physical processes.

Application of x‐ray photoemission electron microscopy developed at SPring‐8 BL15XU

AbstractWe have been developing x‐ray photoemission electron microscopy (XPEEM) designed for measurement with both soft x‐rays and hard x‐rays at SPring‐8 beamline BL15XU, in order to realize two‐dimensional chemical analysis and to establish a technique for the micro‐area x‐ray absorption fine structure (XAFS) for practical materials. In this work, surface images of SbTe amorphous/crystalline patterned film, used as the recording layer for the digital versatile disc—rewritable (DVD + RW), were observed by XPEEM. We have also demonstrated the micro‐area x‐ray absorption near‐edge structure (XANES) of Sb LIII spectra in a 200 × 200 nm2 area by means of XPEEM, and successfully distinguished the spectrum of the amorphous bit region from that of the crystalline region. Copyright © 2004 John Wiley & Sons, Ltd.

Polarization-Free Blu-ray Disc/Digital Versatile Disc Compatible Optical Pick-up

We have developed Blu-ray disc (BD)/digital versatile disc (DVD) compatible technology employing a polarization-free wavefront correction element. The polarization-free wavefront correction elements have high diffraction efficiencies for both BD and DVD. Also, this element has a large decentering tolerance for the objective lens. The effectiveness of this element was confirmed by examining wavefront aberrations for DVD and readout signal waveforms for both BD and DVD.

Blu-ray Disc/Digital Versatile Disc Recording and Reproducing Compatible Use Technology in the 2nd Generation Pick Up for Blu-ray Disc

We developed a 2nd generation pick up for the Blu-ray disc (BD), which makes possible recording and reproducing on both BD and digital versatile disc (DVD), and has a size for audio and visual (AV) and personal computer (PC) applications. These properties are realized by a single objective lens and a newly developed hologram element. The next generation optical disc system, which is expected to enable over 15 GB recording and reproducing on an optical disc, is also expected to record and reproduce on DVD or compact disc (CD), using one pick up. In order to satisfy such demand, we have developed an objective lens with a long working distance and proposed a BD/DVD/CD compatible use technology. This paper reports the details of how we achieved a proper sized AV/PC for common use, BD/DVD recording and reproducing compatible use and the dual layer disc in the 2nd generation pick up for BD.

Lens Design of Compatible Objective Lens for Blu-ray Disc and Digital Versatile Disk with Diffractive Optical Element and Phase Steps

A two-element objective lens which is compatible with for digital versatile disk (DVD) and Blu-ray Disc (BD) and has adequate optical performances in terms of off-axis wavefront and on-axis chromatic aberration for both optical heads has been designed. The first-order diffracted light is used for DVD and the second-order one is used for BD. We analyzed chromatic spherical aberration and found that using first- and second-diffracted lights causes 20 mλ/nm chromatic spherical aberration at a wavelength of 400 nm. However, using 5λ and 10λ phase steps can reduce chromatic spherical aberration to 7 mλ/nm. The designed two-element lens consists of the first plastic lens, on which there is diffractive optical element, and the second plano-convex glass molded lens.

Recording of Multi-Level Run-Length-Limited Modulation Signals on Compact Disc/Digital Versatile Disc Rewritable Discs

Multi-level (ML) recording technology increases the capacity of standard compact disc (CD) and digital versatile disc (DVD) rewritable systems with no change to the optical/mechanical unit. The feasibility of applying ternary run-length-limited (3L-RLL) modulation to recording/playback on standard CD/DVD phase change discs is discussed. The use of 3L-RLL modulation increases the recording density 50% relative to conventional binary RLL (2L-RLL) modulation currently used in CD and DVD systems.

Front Surface Recording Reliability Studies

The data reliability of a front surface optical recording system using a 32 mm disk is demonstrated. The system has approximately the same areal density as the digital versatile disk (DVD) system but utilizes an enhanced error correction coding (ECC) architecture. Theoretical statistical error analysis of the ECC subsystem shows a significantly reduced mis-correction probability. Experimental results from laboratory smoke and dust contamination studies as well as real world experiments performed in an office, a smoky bar, and a greasy kitchen environment are discussed and confirm the robust performance of the system predicted by the theory.

Microminiaturized Aspherical Single Lens with Numerical Aperture of 0.9 for Blue Laser Diode

A single lens with an effective diameter of 0.3 mm and a high numerical aperture (NA) of 0.9 for a blue laser diode has been developed. The current wavefront aberration of the lens is approximately equal to that of a conventional high-NA lens. The optical flying head with a mold process lens (MPL) can be respectively designed so that the disk-tilt margin may become wide for each cover layer thickness of the disk (compact disk, digital versatile disk, etc.).

Photo Replication of Birefringent Phase Structures

Dual layer blu-ray disc (BD) and dual layer small form factor optical drive (SFFO) as well as BD / digital versatile disc (DVD) / compact disc (CD) compatible systems, require phase structures to cope with the different amount of spherical aberration for the various different operating modes. Birefringent phase structures open up to the possibility to cope with these different amounts of aberration in the various readout modes, but so far no manufacturing methods are known which lead to low cost and stable structures. A novel replication method, based on the photo-polymerization of a liquid crystalline monomer is presented to make birefringent phase structures. Apart from enabling mass production, the process allows a phase structure to be directly produced on top of an ordinary objective lens, allowing weight and size reduction of the compatible optical pick up.

Phase-Change Media for Ultrahigh-Speed Digital Versatile Disc Recording

Rewritable discs based on Ge-Sn-Sb phase-change compositions that combine high crystallization rates with good archival life stability were designed. The crystallization rate can be varied from 2–16× digital versatile disc (DVD) speed by variation of phase-change composition. The rate increases with decreasing Ge concentration and is dependent on dopants. For high-speed discs based on these compositions, back growth is substantial, but can be diminished by designing an efficiently cooled stack. By doing so, phase-change optical recording at 10× DVD rewritable (+RW) with 9% multitrack jitter is demonstrated using a 2T-period-based write strategy.

High-Speed 16× Digital Versatile Disk Dye Recording

In dye-based optical recording, thermal interference is a major obstacle for high recording speeds. Detailed studies of recorded data reveal that post-heat from writing of a pit can result in unwanted shrinkage of the previously written pit. To prevent pit shrinkage we apply a castle-type writestrategy. We demonstrate digital versatile disk (DVD) recordings at 16× speed, 1× and intermediate speeds.

Run-Length-Limited (4, 13) Code for High Density Optical Storage Systems

In this paper, we propose a new (4, 13) run-length-limited (RLL) code for high-density optical storage systems. The code rate of this code is 1/3, and the resulting density ratio is 1.67, which is larger than that of EFMPlus code used for digital versatile disc (DVD) systems. The bit error rate (BER) performance of the code is analyzed considering noise and channel jitter. The (4, 13) RLL code has very low complexity of hardware since the mapping rule is simple. The encoding and decoding circuits of the code are implemented using a complex programmable logic device (CPLD) chip.

Effect of Thermal Deformation of Optical Pick-up on the Optical Performance

The effect of thermal deformation of optical pick-up due to laser diode (LD) and LD driving IC on the optical performance of digital versatile disk (DVD) optical system was analyzed using the finite element analysis with initial surface residual stress conditions, and results were compared with the measured results with holographic interferometry. Ray tracing was performed using the deformed configuration of optical system.

Orthogonal Frequency Division Multiplex with Multi-Level Technology in Optical Storage Application

We applied orthogonal frequency division multiplex (OFDM) to the optical storage system. By equalizing the channel and correcting the sampling frequency error in the frequency domain, and by using different modulations according to the bit error rate performance of the different carriers, we were able to increase the recording data density to 2.6 times of that of digital versatile disc (DVD).

New Tracking Servomechanism Using Phase-Shift Differential Push-Pull Method for Recordable Optical Disks

We have improved the phase-shift differential push-pull (PS-DPP) tracking method with a multidivision phase-shift grating, which is applicable to various optical disks with different track pitches and does not require the accurate alignment of the three-spot position on a disk. In this paper we presented the properties of this method in recordable optical disks such as phase-change or dye media in which reflectivity greatly changes after recording. In particular, we found the cause of a radial tracking error signal offset occurring at the boundary between recorded and unrecorded tracks. To resolve this issue, we proposed two solutions: one is the optimum calculation procedure for the PS-DPP signal, and another is a newly designed phase-shift grating for recordable disks. We demonstrated the offset cancellation effect of this improved PS-DPP method using a new hologram laser unit for various types of digital versatile discs (DVDs) and showed its applicability to the Blu-ray Disc (BD).

More than 20 GB Capacity Rewritable Disk with the Same Physical Parameters as that of Digital Versatile Disc, Using a New Recording Method and Domain Wall Displacement Detection

We have developed a new light intensity modulation recording method called domain tail erasing method. This new recording method enables high-density recording far beyond the optical resolution limit with a medium combining the layer structure of domain wall displacement detection (DWDD) with that of light intensity modulation direct overwrite (LIMDOW). A recording performance nearly identical to that using magnetic field modulation (MFM) was confirmed with this method, using conventional optics with a wavelength of 660 nm and NA of 0.60.