• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.7
• /
• pp.87-94
• /
• 2008

The displacement sensor using optical pickup head is presented. The measuring principle of optical pickup head in focusing direction is adopted to measure displacement. The preliminary tests were carried out to verify the feasibility of the optical pickup head as a displacement sensor and optical pickup head showed about $8\;{\mu}m$ measuring range and 10nm resolution. The methodology to expand measuring range is proposed and proved its validity. The proposed displacement sensors are applied to AFM(Atomic Force Microscope) probe head to measure the deflection of micro-cantilever.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.81-82
• /
• 2012

• Transactions of the Society of Information Storage Systems
• /
• v.1 no.1
• /
• pp.29-33
• /
• 2005

We have developed an optical pickup head for blu-ray disc. We have adopted a liquid crystal panel to compensate thickness difference of cover layer. By disposing DVD/CD compatible objective inside the BD objective in disc radial direction, we could realize a backward compatibility. Furthermore we have inserted a polarization diffractive optical element to reduce the influence from the other layer in BD dual layer.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.9
• /
• pp.41-50
• /
• 2002

Optical disk system aiming at fast data transfer rate and high-density recording requires the improvement in performance of the pickup head. Especially, the pickup actuator needs better linearity and stability. So, a lever actuator for optical disk is proposed. In this paper, the role of lever and its structure are discussed and the flexure hinge is introduced to enhance the precise movement. Using the Newoton's method, the motion of equation for the lever actuator is obtained. The results are compared with the analysis results by the FEM (Finite Element Method) for the vibration and the magnetic field. Consequently, the lever actuator has the 2"d system characteristics in 3-axis moving directions and superior stability for the external vibration.tion.

• Korean Journal of Optics and Photonics
• /
• v.16 no.4
• /
• pp.345-353
• /
• 2005

We proposed a new and cost-effective method fer assembling holographic pickup modules without any high resolution vision system. Assembling was accomplished by adjusting photodiode package only, leading to a low cost, holographic pickup module. Focus and tracking error signals were simply determined by comparing spot sizes and by using the 3 beam method, respectively, based on four-sectional holographic optical elements. In experiment, we assembled a hologram module and estimated performance of the proposed method fur a holographic pickup module used in compact disc system.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.253.2-253.2
• /
• 2007

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.9
• /
• pp.961-964
• /
• 2012

This paper presents a sensing system to measure the deflection of a microcantilever in an atomic force microscope. In general, the optical lever method and interferometry are used for the sensing system; however, their size and cost leaves considerable room for improvement. Therefore, we used an optical pickup head whose operating principle is based on the astigmatism of the commercial optical disk drives. The developed sensing system was applied to a laboratory atomic force microscope, and satisfactory results were obtained.