• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.127-133
• /
• 2002

After the vibration source is searched in optical disk drive as an information storage device broadly used the influence of it against FES(Focusing Error Signal) which is a kind of positioning error of pick up from the circuit is carefully examined. For that Purpose, partial coherence function method is applied on a simple multi-degree of freedom model made for the theoretical verification and it is practically introduced in optical disk drive for analyzing the effect of vibration source. Finally, partial coherence output spectrum is attentively observed in order to know which vibration source is a great influence on FES.

• Korean Journal of Optics and Photonics
• /
• v.18 no.4
• /
• pp.256-263
• /
• 2007

High NA objective design by using SELFOC materials was studied, and two kinds of objective for optical pick-up were designed. The SELFOC materials have radial gradient index distribution, and it gives additional degree of freedom in optical design. Therefore, we expect that optical design of high NA objective without aspheric surface will be possible. In this study, the variation of ms spot diameter was investigated as a function of quadratic constant and refractive index on axis for various combinations of axial thickness and entrance pupil diameter. For the survey, Code V was used for optimization and evaluation of the objective lenses. The result suggested that larger quadratic constant and higher refractive index on axis could give us better imaging performance for all combinations of axial thickness and pupil diameter. Based on the survey, we designed high NA objectives for DVR. There were two kinds of design solution consisting two spherical SELFOC lenses. The solution I had positive-positive lens configuration with short over-all-length, but it had poor off-axial performance compared with the solution II. The solution II had negative-positive lens configuration with good off-axial imaging performance. But the solution II had some disadvantages, long over-all-length and large diameter of the second lens.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1095-1096
• /
• 2008

By adding height compensation to the usual 3 points skew adjustment device, an improved functional skew adjustment device is implemented in this paper. The proposed skew adjustment device is for traverse which will be adapted to BD and HD player system requiring more accuracy. and It can adjust not only R/T skew but also height. The system is composed of personal computer, control box, kinematic mechanism device and bar-code reader device. Application programs are implemented by visual basic.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.479-484
• /
• 2000

The topology optimization of electromagnetic systems is investigated and the TOPEM (Topology Optimization for Electromagnetic Systems) is developed using the finite element method (FEM). The design sensitivity equation for topology optimization is derived using the adjoint variable method. The proposed method is validated by applying it to the topology optimizations of a C-core actuator and an optical pickup actuator.

• Proceedings of the Korea Database Society Conference
• /
• 1995.12a
• /
• pp.68-79
• /
• 1995

HiMEDIA 전략 LG의 강점인 H/W 사업분야의 세계일류화를 지향하고, 향후 유망분야인 S/W와 Service 신 사업 참여에 LG의 역량을 집중토록함. $\square$ Hardware 신 사업： ⇒LG의 강점인 Device분야의 신제품의 지속적 개발(DVD, DVCR, HDTV등) ⇒한국 및 해외 Alliance 강화를 통한 VOD 사업 역량 배가 ⇒SI(System Integration)사업에 대한 타당성 검토 ⇒주요 Component의 핵심기술 개발(TFT-LCD, Optical Pick-up등)(중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.977-982
• /
• 2001

In this paper, we deal with the analysis and optimum design of a disc drive feeding system. Using this proposed design method, we can determine an optimal step motor and lead-screw for the shorter seek time and required seek resolution. Simulation results show that this method can be potentially implemented in the design of a feeding system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.232-235
• /
• 2004

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1998.04a
• /
• pp.218-226
• /
• 1998

Recent trends and the effect of mechanical vibrations in optical disk drives are reviewed in this paper. The Nation from CD drives to high density DVD drives and the development of writable optical disk drives require tighter mechanical tolerance. The demand for faster access time and higher data transfer rate also leads to critical mechanical problems to limit the tracking and focusing servo performance. The current mechanical issues to limit the performance of the drives and various technologies to overcome the mechanical problems are introduced. Vibrations of disk-spindle system, actuator and suspension designs of the optical pick-up, and general mechanical designs for the fast and stable access mechanism are considered.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.525-528
• /
• 2003

The aspherical lens are used as objective lens of optical pickup. The sample product is made before manufacturing the injection mould of lens to examine the design factor. The optimum cutting conditions of the main spindle speed, the depth of cut, the feed rate are found when we cut PMMA and PC lens sample with ultra-precision SPDT. The demanded surface roughness 10 nm Ra. aspherical form error 0.5 ${\mu}{\textrm}{m}$ P-V for aspherical lens of optical data storage device are satisfied for PMMA. but not satisfied for PC.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.316.2-316
• /
• 2002

There are a lot of roots of errors in the motion of the optical pickup actuator being one of the most significant components in the CD-ROM drive. Most of the studies recently performed have a tendency to seek fur the causes from an actuator itself. We found the fact that the range of the natural frequencies of a feeding deck and an actuator is close each other through an experiment. This paper present the dynamic characteristics of an actuator affected by the motion of a feeding deck. (omitted)