Gap Servo System for a Biaxial Device Using an Optical Gap Signal in a Near Field Readout System

Ishimoto, Tsutomu; Saito, Kimihiro; Shinoda, Masataka; Kondo, Takao; Nakaoki, Ariyoshi; Yamamoto, Masanobu

doi:10.1143/jjap.42.2719

Cited by 54 publications

(31 citation statements)

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“…When the lens enters the near-field range, the air-gap controller is switched to closed-loop mode. Sony demonstrated 1 nm at a 150-rpm disk (2.5 Hz) [183], whereas Philips recently demonstrated 1 nm air gap at a 3500 rpm (58.3 Hz) polycarbonate disk [184].…”

Section: Near-field Recording Systemsmentioning

confidence: 99%

Control Methods in Data-Storage Systems

Cherubini

Chung

Messner

et al. 2012

IEEE Trans. Contr. Syst. Technol.

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Abstract-The recording performance of data-storage devices, in which write/read elements move relative to a storage medium to reliably store and retrieve information, depends on the capability of servo mechanisms to provide the necessary positioning accuracy. The desired characteristics of servo mechanisms for datastorage systems include robustness against variations of environmental parameters, high resolution, accuracy, stability, and fast response. This paper presents a comprehensive overview of advanced servo-control methods for data storage. The applications are to well-established recording technologies, including magnetic tape and magnetic disk systems as well as CD/DVD/Blue-Ray optical data-storage systems. Moreover, newer holographic and nearfield optical systems and the emerging probe-storage technology are also addressed. Emphasis is given to the potential exhibited by the technologies considered for achieving ultra-high storage capacity, as required by the exploding demand in data-storage capacity for archival systems and massive multimedia data storage.Index Terms-Control systems, hard-disk drive, holographic data storage, optical-disk drive, scanning-probe data storage, servomechanism, tape drive.

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Section: Near-field Recording Systemsmentioning

confidence: 99%

Control Methods in Data-Storage Systems

Cherubini

Chung

Messner

et al. 2012

IEEE Trans. Contr. Syst. Technol.

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“…We used the near field optical disc system reported at ISOM/ODS 2002 [2]. Figure 1 shows the schematic diagram of the near-field readout optics.…”

Section: Experiments Conditionsmentioning

confidence: 99%

High-density near-field readout over 100-GB capacity using a solid immersion lens with NA of 2.05

et al. 2003

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We have achieved high density near field readout of a 100 GB capacity (69.5Gbitlin2) disc by using a solid immersion lens with numerical aperture of2.05. In order to realize the solid immersion lens with numerical aperture of 2.05, the solid immersion lens was made from Bi4Ge3O12 mono-crystal. The refractive index of Bi4Ge3O12 is 2.23 at the wavelength of 405 nm. A conventional optical pick-up actuator with the solid immersion lens was used for the near field optical disc system. We confirmed that the near field readout system is promising method ofrealizing a high density optical disc system.

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“…[27][28][29] Although the NFR optical disk has a fourfold higher data capacity per recording layer than that of Blu-ray disk, the 20 nm gap servo control between the SIL optical head and the disk surface meant that there were difficulties with obtaining a high disk rotational speed for high-data transfer rate recording when the conventional method was used. [30][31][32][33][34] We have proposed a precise gap servo system of reducing harmonics of an axial run-out disturbance-feed-forward control (RHD-FFC) system for the NFR drive. 35) We have also proposed a high-density thin optical disk with a narrow track pitch for NFR with an SIL, and also have reported and indicated the feasibility of high-data transfer rate recording corresponding to 252 Mbps and indicated less than 2 nm of high-precision gap servo control with a small axial run-out between 1 and 10 m p-p , and obtained sufficient carrier-to-noise ratio characteristics at a high disk rotational speed.…”

Section: Introductionmentioning

confidence: 99%

Recording characteristics of high-density thin optical disk using near-field optical recording

Koide

Kajiyama

Sato

et al. 2014

OPT REV

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We report on the recording characteristics of a near-field optical recording thin optical disk (NFR-TOD). We proposed a new cooling-less-type write strategy for recording, applied it to the NFR-TOD experimental system, and also applied a partial response maximum likelihood (PRML) signal processing, which was evaluated and optimized the PR coefficient for playback signals of the prototype NFR-TOD. The NFR-TOD has a track pitch of 160 nm and improved recording characteristics. The experimental results of the prototype NFR-TOD and the system indicate sufficiently low bit error rates (bERs) for recorded data at a fourfold higher recording density than the current Blu-ray disk.

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Gap Servo System for a Biaxial Device Using an Optical Gap Signal in a Near Field Readout System

Cited by 54 publications

References 1 publication

Control Methods in Data-Storage Systems

Control Methods in Data-Storage Systems

High-density near-field readout over 100-GB capacity using a solid immersion lens with NA of 2.05

Recording characteristics of high-density thin optical disk using near-field optical recording

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