• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.376.2-376
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• 2002

In this study, the shape of suspension load beam for NFR(Near Field Recording) was proposed, which was designed using Topology optimization based on Homogenization method. Lens and Micro-mirror are attached to the end of the suspension load beam for collection and control the light, which increasing the system mass. Increment of the system mass cause to decrease the tracking stiffness mode frequency. (omitted)

• Transactions of the Society of Information Storage Systems
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• v.2 no.4
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• pp.219-223
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• 2006

Near field recording(NFR) technology has been considered as a strong candidate to surpass the far-field diffraction limit imposed by the nature of light in present optical disk drives such as CD, DVD, and BD(Blu-ray Disk). In this paper, we suggest novel inside near-field dual layer recording concept using elliptic shape solid immersion lens(ESIL).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.487-488
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.609-612
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• 2008

The solid immersion lens (SIL) based near-field recording (NFR) system is considered as one of the high density optical data storage system. For the NFR servo system, tracking servo control is a difficult technology to maintain extremely small gap between SIL and media within one twentieth. This is because the track pitch is decreased for increasing the recording density. In this paper, we propose disturbance observer (DOB) and internal model principle (IMP) for disturbance rejection due to eccentricity of disk. The performance of tracking controller using DOB is increased by about 85%, 94%, 97% using Q filters that have bandwidths of 50Hz, 125Hz, 250Hz, respectively. Moreover, IMP based controller is effectively reduced the residual error.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.37-45
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• 2001

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.718-721
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• 2001

For higher recording density in optical data storage, near field optics is being actively researched as one of the promising alternatives. But the tight assembling tolerance in NFR is one of big barriers to overcome for the realization of it. In this paper, the tolerances in assembling optic components of NFR system are analyzed. Some of key tolerances can be loosened by the optimization of objective lens design. But one of them become too tight by the optimization and should be controlled by other means. One of possible methods to control the tolerance is discussed.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.80-86
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• 2005

Optical performance evaluation results and an interference fringe pattern analysis of alignment errors for an optical head of a near-field receding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties to assemble the small focusing unit precisely. We composed an evaluation system with an interferometer and evaluated some focusing unit samples aligned and assembled by manual and present the obtained results. Using the conventional optical tool, Code V, a tolerance analysis of the alignment error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the conceptual auto-alignment methodology using a neural network approach is considered.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.3
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• pp.164-171
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• 2003

Dynamic analysis using impulse responses is formulated to estimate effect of slider rail shape on dynamic responses in near-field optical recording drive. Impulse responses are obtained on numerical nonlinear model including rigid motion of a slider and fluid motion of an air bearing under the slider. Dynamic characteristics of slider motion are evaluated by utilizing the decay ratio of impulse responses and modal frequencies from frequency response functions. The dynamic characteristics of the designed NFR slider are checked by comparing those of a HDD slider(Nutcracker). Also, sensitivities of slider Position conditions and rotation speed on the dynamic characteristics are investigated.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.363-371
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• 2000

There are some concepts that could achieve Near-Field Recording (NPR). One of concepts is the use of the flying head with Solid Immersion Lens (SIL). The basic concept of this is almost same with that of Hard Disk Drive (HDD). This study presents the flying characteristics of the slider for NFR. Numerical simulations are performed using FEM and Broydon-Fletcher-Goldfarb-Shanno (BFGS) method. Some modifications are considered to improve flying characteristics of the slider.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.12-13
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• 2005

Near field recording (NFR) technology with SIL has been thought as the most promising generation optical storage device. A gap distance between the SIL and the disc should be controlled to be 20${\~}$40nm. We observed gap error signal in our NFR test-bed using a blue LD (405nm). The digital gap servo filter and control algorithm were developed to maintain a constant air gap by adopting a conventional actuator.