• Electrical & Electronic Materials
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• v.10 no.3
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• pp.289-294
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• 1997

디지탈 비디오 디스크의 약어로 지칭되는 DVD는 현대 과학이 이루어낸 레이저 광에 의한 정보의 기록과 재생을 한층 승화시킨 차세대 package형 광 기록 매체이다. 앞으로 이 제품군은 기존에 분리되어 있던 가전과 컴퓨터의 응용분야를 이어주는 교량역할을 할 새로운 개념의 상품으로 기대된다. 본 고에서는 DVD의 기술적 배경 및 이의 구현을 위해 활용된 요소기술, 그리고 미래기술로의 흐름에 관해 소개고자 한다.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.310-315
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• 2010

Theoretical and experimental investigations of moires in 3D displays were performed. To describe and minimize moires, we propose the polar representation form of moire waves. The experimental and theoretical data are in good agreement except in the neighborhood of the minimization angle. The implicit formulas are found for visible moires of line gratings at finite distances. The computer simulation and the physical experiments confirm the moire appearance for this case.

• Journal of the Optical Society of Korea
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• v.6 no.2
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• pp.21-26
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• 2002

Interferometric metrology with a null CGH(computer-generated hologram) is presented for measuring highly aspheric surfaces used in a large screen projection television system with high accuracy. The cubic spline surface model which works in a single-pass configuration with a refractive index of object space 0 is used for designing a null CGH. A hybrid null corrector with plano-concave lens in front of a CGH is presented to make the CGH easier to fabricate. Experimental results are presented to demonstrate the validity of the proposed technique.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.189-190
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.36-37
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• 2004

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.1 s.94
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• pp.12-19
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• 2005

This paper proposed a dual actuator using Bimorph PZT for information storage device based on prove array NSOM(near-field scanning optical microscopy). The gap between the media and the optical head should be maintained within the optical tolerance. Therefore, a new actuator having high sensitivity is required. Bimorph PZT, which has fast access time and high sensitivity characteristic, is suitable for this precise actuating system. This paper is focused on derivation of mathematical model of dual Bimorph PZT actuator and control algorithm. Hamilton's principle was used for mathematical model. The model is verified by FEA(finite element analysis), and compared with experimental results. Different control algorithms were used for two Bimorph PZT actuating same direction and opposite direction. The gap between recording media and optical head was controlled within 20nm in experiment.

• Smart Media Journal
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• v.10 no.4
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• pp.80-90
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• 2021

Using optical music recognition technology based on deep learning, we propose to apply the results derived to VR games. To detect the music objects in the music sheet, the deep learning model used YOLO v5, and Hough transform was employed to detect undetected objects, modifying the size of the staff. It analyzes and uses BPM, maximum number of combos, and musical notes in VR games using output result files, and prevents the backlog of notes through Object Pooling technology for resource management. In this paper, VR games can be produced with music elements derived from optical music recognition technology to expand the utilization of optical music recognition along with providing VR contents.

• Journal of Technologic Dentistry
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• v.43 no.4
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• pp.145-152
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• 2021

Purpose: This study aimed to produce resin prosthetics using a dental barrel finishing machine. For dental resin grinding, the ingredients of the barrel finishing media were analyzed, and surface residues of the resin were observed. Methods: Two types of barrel finishing media for dental resin grinding were tested. Specimens were made from thermal polymerized, auto polymerized, and photopolymerized resins. Finishing media were analyzed through energy-dispersive X-ray spectroscopy (EDS) component analysis and inductively coupled plasma-optical emission spectrometry (ICP-OES) component analysis. Then, the prepared specimen was barrel finished for 25 minutes using two types of barrel finishing media, and scanning electron microscope was photographed to observe the surface residues. Results: As a result of EDS component analysis, both types of finishing media were analyzed for the components of C, O, Zr and Al elements, and industry media (IM) was further analyzed for the components of Si and Mg elements. In the ICP-OES component analysis, Cd and As, which are harmful elements, were detected in IM, and no harmful elements were detected in manufacturing media (MM). Because of observation of surface residues, no residues were observed in the three types of resin specimens that were barrel finished with two types of finishing media. Conclusion: Surface residue wasn't observed on the specimens polished using two types of finishing media. However, in IM, Cd and As, which are harmful elements, were detected, making it inappropriate for clinical use. In MM, harmful elements were not detected; therefore, clinical use will be possible.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.386-389
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• 2003

Recent issues in Optical Disk Drive (ODD) are focused on small size. Blu-ray Disk (BD), using blue laser (405nm wavelength) and high NA (0.85) objective lens. can store 25Gbyte on a conventional 12cm optical disk. Small Form Factor Optical (SFFO) drive uses 3cm disk which can store 1.5Gbyte on a disk. This kind of Small Form Factot Optical (SFFO) drive correspond to PCMCIA type memory (Compact Flash or Micro Drive). Preferably, Optical Disk has relatively low cost of the storage media per Byte rather than PCMCIA type memory. To make Small Form Factor Optical (SFFO) drive. optical pickup and its component must be miniaturized. Miniaturization of the component needs new concept of Optical Pickup. This paper is focused on two main subjects. One is Objective Lens design which can be manufactured on a wafer, and the other is optical path design of the pickup which has 2mm thickness.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.93-98
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• 2005

Rewritable optical disk is one of the essential data storage media in these days, which takes advantage of the different optical properties in the amorphous and crystalline states of phase change materials. As well known, data transfer rate is one of the most important parameter of the phase change optical disks, which is mostly limited by the crystallization speed of recording media. Therefore, we doped Sn/Bi to $Ge_2Sb_2Te_5$ alloy in order to improve the crystallization speed and investigated the dependence of phase change characteristics on Sn/Bi doping concentration. The Sn/Bi doped $Ge_2Sb_2Te_5$ thin film was deposited by RF magnetron co-sputtering system and phase change characteristics were investigated by X-ray diffraction (XRD), static tester, UV-visible spectrophotometer, electron probe microanalysis (EPMA), inductively coupled plasma mass spectrometer (ICP-MS) and atomic force microscopy (AFM). Optimum doping concentration of Bi and Sn were 5${\~}$6 at.$\%$ and the minimum time for crystallization was below than 20 ns. This improvement is correlated with the simple crystalline structure of Sn/Bi doped $Ge_2Sb_2Te_5$ and the reduced activation barrier arising from Sn/Bi doping. The results indicate that Sn/Bi might play an important role in the transformation kinetics of phase change materials..