Design of moving magnet type pickup actuator using inserted coil

• Published in: Microsystem technologies Vol. 15; no. 10-11; pp. 1719 - 1728
• Main Authors: Song, Myeong-Gyu, Kim, Yoon-Ki, Park, No-Cheol, Yoo, Jeonghoon, Park, Young-Pil, Onagi, Nobuaki, Akanuma, Goichi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-10-2009; Springer
• Subjects: Applied sciences; Electronics; Electronics and Microelectronics; Engineering; Exact sciences and technology; Instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Magnetic and optical mass memories; Mechanical Engineering; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Micromechanical devices and systems; Miscellaneous; Nanotechnology; Physics; Precision engineering, watch making; Storage and reproduction of information; Technical Paper; Data Transfer Rate; Optical Pickup; Flexible Mode; Wire Suspension; Digital Versatile Disc; Elastic constant; Optical storage; Optical disk; Sensitivity analysis; Vibration; Deformation modulus; High definition television; Magnet; Data storage; Modeling; Optimization; Young modulus; Experimental design; Bandwidth; High frequency; Read head; Actuator
• ISSN: 0946-7076; 1432-1858
• DOI: 10.1007/s00542-009-0874-6

Recently, the demand of the information storage devices with large storage capacity such as Blu-ray Disc and high-definition television is increased. In keeping with this trend, the optical storage devices are also required to have high data transfer rate and large storage capacity. To satisfy these requirements, the actuator for optical disc drive should have a high servo bandwidth to compensate the vibration of optical disc. The servo bandwidth is limited by some flexible modes of the actuator, thus it is essential to make these frequencies of flexible modes to high frequency region. The frequency of flexible mode depends on materials and shape. Stiff materials and simple shape is useful to increase the frequency of flexible mode. In this paper, we suggested a moving magnet type actuator having flexible modes which are happened at high frequency region. Generally, the moving magnet type actuator has an advantage to increase the frequency of flexible mode because the moving magnet type actuator has simple structure and the Young’s modulus of magnet is high. However, large moving mass and inefficiency of Electromagnetic (EM) circuit cut down driving sensitivities of actuator. To improve driving sensitivities, we designed the model with the closed EM circuit for tracking actuation. The design of experiments (DOE) procedure is applied to get proper design parameters and the variable metric method (VMM) which is a technique of optimization is used to improve driving sensitivity. The lens holder is also improved based on the optimization result of EM circuit. And to make up for the low efficiency of EM circuit, the thermal stability is checked on condition that the input current is very high. At last, the final design of moving magnet type actuator is suggested and it is verified that the driving performance and the structural stiffness of the final design is sufficient.