• Journal of KSNVE
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• v.8 no.1
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• pp.87-98
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• 1998

A Precise actuator in the pick-up of a DVDR/P(Digital Video Disk Recorder/Player) is required to control position accurately. Therefore, in order to develop a reliable actuator, dynamic characteristics of each part in an actuator should be examined closely. This paper presents systematic design process of an actuator using various analysis methods to confirm fundamental capability and solve performance problems related to dynamic characteristics of an actuator beforehand. Particularly, sensitivity analysis is presented through the program using mass moment of inertia and general equations of rigid body. Through the result of sensitivity analysis, important inferiority causes of actuator are selected and reduced. In the end, dynamic characteristics of manufactured actuators are improved considerably.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.342-345
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• 2004

We design a new actuator in order to achieve 3-axes motion for high performance optical device. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in terms of prices and manufacturing. To predict the features of actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis are used From comparing simulated data with experimental results, we verified the accuracy of the simulation and the superiority of the present actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.362-365
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• 2004

'Coil' occupies a much important position in delivering driving force of optical pick-up actuators. Up to now the main stream has been a winding coil type actuator, but actuators using FP-Coil(Fine Pattern Coil) have been considered for the more compacted and simple manufacturing process and have variously spreaded the application fields by product. We have tried to design actuators using PCB-Coil(Printed Circuit Board Coil) which has benefits in terms of price and manufacturing process. Especially this research has two main things those are to reduce the vibration of sub-resonance and to assure the do sensitivity in the performance of asymmetric optical pick-up actuator with PCB-Coil.

• Journal of KSNVE
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• v.8 no.3
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• pp.533-541
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• 1998

Recently, optical disk drives are increasingly demanded to have higher speed as well as high information density, especially for applications like CD ROM drives. To this end, improvement of their optical pickup structure and control is recognized the very challenging issue. In this paper, the pickup is first analytically modelled in a plane to describe its coupled auto-focusing and auto-tracking motions. Subsequently, the model is linearized and combined with actuator dynamics for the auto-focusing system. With its unmeasurable parameters being estimated based on experimental data, an approximate I-DOF linear model is obtained neglecting the coupling term. To design the high speed and robust positional servo controller realistic design specifications are addressed, and H control method is employed based on the approximate model. Finally, taking the pickup in a commerical high speed CD ROM drive as an example performance of the designed controller is verified through realtime experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.195-199
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• 2004

Recently, optical disc drives are required to have high density and capacity in according with development of high definition images and rapid increase of various informations. Consequently, the numerical aperture becomes larger, the wavelength of laser is coming to be short. However, it deteriorates rolling mode effect on an optical pickup actuator. Therefore, this paper proposes new design and optimization of tracking coils for reducing it. First, we verify that discord between the center of force and the center of mass by restrictions of design condition is an important factor of rolling mode effect. Then, in order to reduce it, we propose new design parameters of tracking coils. Finally, we reduce rolling mode effect through optimization of tracking coils using Taguchi method and response surface method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.156-160
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• 2005

We design a new actuator of 3-axis motion for high performance optical devices. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in price and manufacturing. To predict the characteristics of the actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis were used. By comparing simulation data with experimental results, we verified the accuracy of the simulation and the superiority of the present.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.220-225
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• 2003

Recent issue of optical actuator is applying to mobile device. It leads actuator to become smaller than conventional type. This paper proposes the design of micro actuator plate spring and analysis of its vibration characteristic. Considering natural frequency of spindle motor, 1st and 2nd eigenfrequency of micro actuator must avoid its natural frequency. First, magnetic circuit is designed by using fine pattern coil and magnetic force is acquired by simulation program. Then, concept design is achieved by topology optimization. From concept design, micro actuator plate spring is embodied through DOE(design of experiment). Finally, considering vibration characteristic simultaneously, optimal plate spring design is determined by RSM(response surface method).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.214-219
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• 2003

Recently, the optical disk drive that is thin in thickness has been demanded by the popularization of notebook PC. The device that controls the thickness of a drive is the height of optical pickup. Therefore, researches about this are going on and an asymmetric actuator is the good choice fur this target. However, the actuator of this design has troubles that a subsidiary resonance is likely to be actuated by discord between the center of force and the mass of renter. In this paper, relation between the tracking coil and the subsidiary resonance is analyzed and dynamic characteristics of an actuator are improved by using experiments design and response surface method.

• Journal of KSNVE
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• v.9 no.5
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• pp.984-990
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• 1999

This paper presents the geometrical methodology to decouple the vibration modes of an elastically supported single rigid body in three-dimensional space. It is shown that the vibration modes can be decoupled by placing the center of elasticity at suitable locations and thereby yielding the plane(s) of symmetry for the given stiffness matrix. The developed methodology has been applied to the actuator supported by the 4-wire suspensions in optical discs, which has one plane of symmetry. For this numerical example, the axes of vibrations have been computed and illustrated with the natural frequencies. The forced response at the objective lens is represented and its geometrical interpretation has been explained as the mutual moment between the axis of vibration and the applied wrench times the line coordinates of the axis of vibration.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.175-181
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• 2005

SiOB is an essential part of slim optical pickup, where the silicon mirror, LD stand, silicon PD are integrated and LD is flip chip bonded. SiOB is fabricated with bulk micromachining. Especially the fabrication of silicon wafer with stepped concave areas has many extraordinary difficulties. As a matter of fact, experiences and knowledges are rare in the fabrication of the highly stepped silicon wafer. The difficulties occurring in the integration of PD and SiOB, and highly stepped patterning, and silicon mirror roughness and how-to-solve will be discussed.