Blu-ray Disc Recordable Research Articles

Development of micro/nano structure pattern generation using direct-beam interferometry

To generate periodic patterns with a 300 nm periodicity on PET substrate, a low-cost direct-beam interferometry device with a 405 nm GaN semiconductor laser diode (Nano Materials) is employed. A similar, cost-effective system was utilized to create periodic patterns with periods between 290 and 750 nm over a vast area using an AlInGaN 405 nm diode. While interference lithography devices are inexpensive and simple to use, they have the drawback of only being able to recreate periodic patterns that are defined by the interference patterns of the laser beams. We present a low-cost direct write lithography system that use the optical head assembly from a Blu-ray disc recorder and is capable of producing both periodic and non-periodic, high-resolution structures for use in Macro/micro/nano processes. The optical head assemblies in Blu-ray drives feature a semiconductor laser diode and a 0.85 NA objective lens for reading optical media. We can attain very huge volumes of homogeneity, throughput, process control, and reproducibility using this Direct Beam approach. We optimized simulated patterns with controlled periodicity, density, and aspect ratio by altering different input parameters and was achieved to 51 nm.

Plasmonic-Enhanced Photocurrent Generation of Organic Photovoltaics Induced by 1D Grating and 2D Crossed Grating Structures.

In this work, plasmonic-enhanced photocurrent generation in organic photovoltaic (OPV) devices is demonstrated. One-dimensional (1D) and two-dimensional (2D) crossed grating structures are created on the active-layer surface composed of a blend of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) via a nanoimprinting technique using a template of a Blu-ray disc recordable (BD-R) grating structure. After formation of aluminum back electrodes, the grating-coupled surface plasmon (GCSPR) and light scattering observed in the devices with grating structures provide a 12.3% and 11.0% enhancement of the photocurrent for the devices with 1D grating and 2D crossed grating structures, respectively. The OPV devices with the 2D crossed grating show a plasmonic-enhanced photocurrent under irradiation with light with all polarization directions, whereas those with the 1D grating provide plasmonic enhancement only under illumination with p-polarized light.

Effect of Micro/Nanostructured P3HT:PCBM Surfaces on the Performance of Organic Photovoltaic Devices

In this study, the effect of periodic patterned micro/nanostructures on the active layers of thin-film organic photovoltaics (OPVs) was investigated to improve the device performance. The patterned active layer structures were fabricated by a nanoimprinting technique using different templates, including compact disc recordable (CD-R), Blu-ray disc recordable (BD-R), nanowell arrays, nanodot arrays, and honeycomb structures. The OPVs consisted of Al/nanostructured P3HT:PCBM/PEDOT:PSS/ITO. Compared with a flat reference OPV, all the micro/nanostructured OPVs exhibited higher performances, originating from enhanced light absorption due to light scattering and surface plasmon excitation at the patterned Al/P3HT:PCBM interfaces.

Enhanced organic solar cell performance: Multiple surface plasmon resonance and incorporation of silver nanodisks into a grating-structure electrode

In this study, plasmonic nanostructures were examined to enhance the light harvesting of organic thin-film solar cells (OSCs) by multiple surface plasmon resonance (SPR) phenomena originating from the grating-coupled configuration with a Blu-ray Disc recordable (BD-R)-imprinted aluminum (Al) grating structure and the incorporation of a series of silver nanodisks (Ag NDs). The devices with such a configuration maximize the light utilization inside OSCs via light absorption, light scattering, and trapping via multiple surface plasmon resonances. Different types and sizes of metallic nanoparticles (NPs), i.e., gold nanoparticles (Au NPs), Ag nanospheres (Ag NSs), and Ag NDs, were used, which were blended separately in a PEDOT:PSS hole transport layer (HTL). The device structure comprised of grating-imprinted-Al/P3HT:PCBM/Ag ND:PEDOT:PSS/ITO. Results obtained from the J–V curves revealed that the power conversion efficiency (PCE) of grating-structured Al/P3HT:PCBM/PEDOT:PSS/ITO is 3.16%; this value is ~6% higher than that of a flat substrate. On the other hand, devices with flat Al and incorporated Au NPs, Ag NSs, or Ag NDs in the HTL exhibited PCEs ranging from 3.15% to 3.37%. Furthermore, OSCs with an Al grating substrate were developed by the incorporation of the Ag ND series into the PEDOT:PSS layer. Compared with that of a reference device, the PCEs of the devices increased to 3.32%–3.59% (11%–20% improvement), indicating that the light absorption enhancement at the active layer corresponds to the grating-coupled surface plasmon resonance and localized surface plasmon resonance excitations with strong near-field distributions penetrating into the active layer leading to higher efficiencies and subsequent better current generation.

Grating-coupled surface plasmon resonance enhanced organic photovoltaic devices induced by Blu-ray disc recordable and Blu-ray disc grating structures.

In this work, we studied the performance enhancement of organic thin-film solar cells (OSCs) originating from the presence of diffraction gratings on the surface of the active layer. Two types of diffraction gratings, periodic gratings (Blu-ray disc recordable: BD-R) and quasi-random gratings (Blu-ray disc: BD), were employed as master templates for grating structures. The grating structures were introduced to the surfaces of poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) films, which were the active layers of the solar cells. The addition of the grating structures led to an increase of light absorption in the absorption region of P3HT:PCBM induced by light scattering. Furthermore, the grating-coupled surface plasmon resonance generated additional light absorption peaks. With illumination of non-polarized light at a normal incident angle, the short-circuit current densities of the BD-R and BD solar cells improved by 11.05% and 10.6%, respectively. Efficiency improvements of 19.28% and 3.21% were also observed for the BD-R and BD devices, respectively. Finally, the finite-difference time-domain simulation results revealed an enhanced electric field in the P3HT:PCBM layer, especially in the BD-R OSC devices.

Investigation of localized surface plasmon/grating-coupled surface plasmon enhanced photocurrent in TiO2 thin films.

We fabricated plasmonic gold nanoparticle (AuNP)-TiO2 nanocomposite films and measured the photocurrent that originates from the water-splitting reaction catalyzed by the AuNP-TiO2 nanocomposite photoelectrocatalytic (PEC) electrode. The localized surface plasmon resonance (LSPR) of the gold nanoparticles affected the generation of photocurrent by TiO2 upon illumination with visible light. Electrochemical impedance spectroscopy (EIS) revealed that the improvement in the photocurrent generation originates from an enhancement in electron-hole pair generation induced by the SPR of the plasmonic gold nanoparticles rather than the extension of the electron lifetime. Moreover, we introduced a novel method to enhance the photocurrent of TiO2 by a multiple plasmonic effect, i.e., LSPR of plasmonic gold nanoparticles and the grating-coupled propagating SP on a gold grating. We fabricated the AuNP-TiO2 nanocomposites on a gold-coated Blu-ray disc recordable (BD-R). The enhancement of the photocurrent due to the combination of LSPR and the grating-coupled SP was investigated.

BD-R 장기보존 특성 평가를 위한 가속 열화 실험 조건과 안정성 평가 기준에 관한 연구

The Blu-ray Disc Recordable(BD-R) is one of strong candidates for archival application among optical media formats, because of its large capability. However, the well-defined accelerated aging test conditions and evaluation criteria have not yet been fully confirmed for BD-R. In this study, the data stability and degradation aspect of BD-R were analyzed by the random-symbol error rate(R-SER) measurement after the accelerated aging test. And a reasonable test condition of accelerated aging for BD-R and the appropriate evaluation criterion using R-SER measurement were discussed.

High resolution, low cost laser lithography using a Blu-ray optical head assembly

We present a novel, cost-effective laser lithography system capable of producing periodic and non-periodic patterns with sub-micrometre feature sizes and periodicities. The optical head assembly of a Blu-ray disc recorder containing a 405nm semiconductor diode laser and 0.85 NA objective lens was mounted on a motion stage and it was used to expose silicon samples covered with a mixture of SU-8 photoresist and photoinitiating chemicals. Experiments were carried out to demonstrate the lithographic capabilities of the system, and a smallest feature size of 450nm was obtained. Grating structures were fabricated in order to demonstrate system capabilities.

Analysis of Phase Multilevel Recording on Microholograms

An optical phase multilevel recording technique using a microholographic system and phase-diversity homodyne detection for enhancement of optical disc capacity is investigated. In this technique, multilevel phase signals are stored as the fringe shifts along the optical axis and recovered from the arctangent of two homodyne-detected signals. For comparison, phase signals from Blu-ray Disc read-only memory (BD-ROM) and Blu-ray Disc recordable (BD-R) media obtained by phase-diversity homodyne detection are experimentally evaluated. From the experimental results, we demonstrated that phase-diversity homodyne detection is useful for detecting the phase signal modulation of the signal beam from an optical disc. Furthermore, simulation results on microholograms indicate that phase signals from the microholograms are much more stable despite the variety of their sizes than those from BD-ROM. These results demonstrate the potential of this multilevel recording method.

High Response Twin-Objective Actuator with Radial Tilt Function for Blu-ray Disc Recorder

We have developed Blu-ray Disc (BD) optical pick-up with a twin-objective lens actuator which is compatible with compact disc (CD) and digital versatile disc (DVD) in the high-speed BD-read only memory (ROM) and BD Recorder. In order to readout CD and DVD in BD Recorder, we adopted twin-objective lens actuator in consideration of optical utilization efficiency, optical performance and insurance of sufficient working distance (WD). This twin-objective lens actuator has two objectives in radial direction, one is for CD/DVD and the other is for BD. Through our careful investigation in design process, this actuator has extremely high AC sensitivities and good 2nd resonance characteristics in consideration of twin-objective actuator. Also, this actuator has linearity in wide focus range, that is to say, more than ±1.0 mm and has radial tilt function which is tilt range more than 7 deg.

A highlight scene detection and video summarization system using audio feature for a personal video recorder

The personal video recorder such as recordable-DVD recorder, Blu-ray disc recorder and/or hard disc recorder has become popular for a large volume storage device for video/audio content data and a browsing function that would quickly provide a desired scene to the user is required as an essential part of such a large capacity recording/playback system. We propose a highlight scene detection function by using only 'audio' features and realize a browsing function for the recorder that enables completely automatic detection of sports highlights. We detect sports highlights by identifying portions with "commentator's excited speech" using Gaussian mixture models (GMM's) trained using the MDL criterion. Our computation is carried out directly on the MDCT coefficients from the AC-3 coefficients thus giving us a tremendous speed advantage. Our accuracy of detection of sports highlights is high across a variety of sports.

A 0.18-/spl mu/m CMOS front-end processor for a Blu-Ray Disc recorder with an adaptive PRML

This paper describes a front-end processor for Blu-Ray Disc (BD) recorder applications. It integrates a partial response maximum likelihood (PRML) block, a data processor (DP) block, and a servo block. The PRML includes an analog-to-digital converter (ADC) and two digitally controlled oscillators (DCO) for data phase-locked loop (PLL) and wobble PLL. A nonlinear equalizer is designed to compensate for high-frequency signal components without increasing inter-symbol interference (ISI). A Teaklite DSP, an ADC, and a digital-to-analog converter are embedded for servo controls. The functions of 17PP modem and error correction code (ECC) are also implemented. Due to the proposed nonlinear equalizer in PRML, less than 2 /spl times/ 10/sup -4/ of symbol-error rate (SER), defined in the Blu-Ray Disc format book, is achieved with tangential tilt margin of /spl plusmn/0.5/spl deg/. This system on a chip (SOC) is fabricated in 0.18-/spl mu/m one-poly five-metal CMOS technology. It contains 12 million transistors in a 50-mm/sup 2/ die and consumes 0.9 W with a channel clock of 132 MHz in 2/spl times/ playback mode.

The front-end SOC for a Blu-ray disc recorder

This article introduces issues on the implementation of a front-end processor for Blu-ray disc (BD) recorder applications. This processor includes partial response maximum likelihood, a data processor block, and servo blocks. The nonlinear equalizer is designed to boost high-frequency signal components without increasing intersymbol interference. It can improve the quality of the high-frequency signal fed into the Viterbi detector, reduce jitter, and offer more tilt margins to the system. Due to the proposed nonlinear equalizer in PRML, less than 2 /spl times/ 10/sup -4/ of the symbol error rate (SER), defined as the BD format book, is achieved with the tangential tilt margin of /spl plusmn/0.5/spl deg/. This system on a chip carries DP functions of a parity preserve/prohibit repeat minimum transition runlength (RMTR) (17PP) modem, Reed-Solomon (RS) codec, and buffer management. The Teaklite DSP is embedded for control functions such as focus servo, track servo, and auto calibration. It contains 12 million transistors in a 50 mm/sup 2/ die, and is fabricated in 0.18 /spl mu/m 1-poly 5-metal (1P5M) CMOS technology.