• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.217-221
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• 2005

Nowadays, HD(High Definition) broadcasting is popular all over the world. Many people want to record the HD level contents. BD(Blu-ray Disc) is developed to satisfy the needs. BD player for home movie system was manufactured already. ODD maker will produce BD Drive for PC(Personal Computer) within few months. Backward Compatibility is very important point in BD Drive. Until now, two OL(Object Lens), two optical pickup and two deck system are proposed. We suggest Single OL system in this paper. Single OL is composed of two optical parts and it's weight is heavy. We introduce the magnetic circuit composed of two 3-Pole magnets. In Spite of heavy OL, We achieve the New Actuator which has high performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.580-586
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• 2005

In this study, experimental tests for driving noise of various optical disk drives (ODD) have been performed using 1/2' microphone noise measurement system. Several new and old ODD models by different manufacturers are practically considered and compared far realistic driving conditions. Sound insulation case with absorbing material fur the present experimental tests is designed and constructed using CATIA system. It is found that average data transfer rate, operating RPM, and sound noise level seems to be different for the same opposed speed ODD by different manufacturers. Moreover, driving sound noise level can be largely affected by both tray shape and driving speed even for the same apparent data transfer rate.

• 소음진동
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• 제9권4호
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• pp.693-702
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• 1999

We study the characteristics of airflow and sound noise induced by disk rotation in optical disk drives. The characteristics of airflow around a rotating disk surrounded by various tray structures are numerically investigated using a commercial CFD program and then compared with experimental results. Sound pressure and intensity caused by the fluid-structure interactions in the CD/DVD-ROM drive are measured, and the effect of the ariflow on the sound noise and disk vibration is discussed. In order to reduce airflow-induced noise and vibration around the rotating disk, tray geometry is modified. Both numerical and experimental studies implemented with different tray models show that the improved tray model alters the characteristics of the disk-induced airflow, causing the reduction of the airflow-induced sound level.

• 한국소음진동공학회논문집
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• 제15권10호
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• pp.1169-1176
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• 2005

In this study, experimental tests for driving noise of various optical disk drives (ODD) have been performed using 1/2' microphone noise measurement system. Several new and old ODD models by different manufacturers are practically considered and compared for realistic driving conditions. Sound insulation case with absorbing material for the present experimental tests is designed and constructed using CATIA system. It is found that average data transfer rate, operating RPM, and sound noise level seem to be different for the ODD models with same denoted speed by different manufacturers. Moreover, driving sound noise level can be largely affected by both tray shape and driving speed even for the condition of the same apparent data transfer rate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.867-870
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• 2002

In high-speed optical disk drive, the excitation caused by rotation of a mass-unbalanced disk is a major source of vibration. The vibration can be a disturbance to the servo system, which is sufficient to cause severe failures in the reading and writing process. The vibration also causes users to feel unpleasantness. The vibration reduction is therefore essential for the reliable operation of optical disk drive. One of the approaches to reduce the vibration is a dynamic vibration absorber (DVA). In this paper, we analyze the dynamic behavior of $DVD\pmRW$ combo drive system with DVA through 12_dof rigid multi-body dynamic model. The effective location and the optimal frequency ratio are obtained from the analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.958-961
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• 2002

The optical disk drive is a basic option on the PC now. So the lower price and higher read/write speed goods are now on market. These trends make many difficulties to produce more reliable drives, comparing when they are treated as high price stuff. In mechanical terms, the lower price and higher read/write speed drive make higher vibration and noise, lower stiffness, even severe fracture of cheap and low quality disk, problems. Due to the internal crash of P/U inside of the drive, the failure of drives, inferior drives, increase more and more by the careless transportation and the originated low stiffness parts. This report is the introduction of the FE simple model to decrease the internal P/U crash problems, and the results.

• 한국소음진동공학회논문집
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• 제16권5호
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• pp.529-536
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• 2006

In high-speed optical disk drive, the excitation caused by rotation of a mass-unbalanced disk is a major source of vibration. The vibration can be a disturbance to the servo system, which is sufficient to cause severe failures in the reading and writing process. The vibration also causes users to feel unpleasantness. The vibration reduction is therefore essential for the reliable operation of optical disk drive. One of the approaches to reduce the vibration is a dynamic vibration absorber(DVA). In this paper, we analyze the dynamic behavior of $DVD{\pm}RW$ combo drive system with DVA through 12-dof rigid multi-body dynamic model. The effective location and the optimal frequency ratio for the DVA are obtained from the analysis. The DVA are fabricated based on the analysis and its usefulness is confirmed.

• 한국소음진동공학회논문집
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• 제15권10호
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• pp.1148-1159
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• 2005

In this paper, the various uncertainties generated in an optical disk drive (ODD) and the robust servo designs considering the uncertainties are studied. First, the brief introduction an ODD and the servo error tolerance of it are discussed. Then, the classifications of uncertainty and the concept of relative stability are introduced. Considering the uncertainty of an ODD, two robust control approaches are applied: (i) mixed sensitivity approach in H$\infty$ control theory for unstructured uncertainty, (ii) QFT for structured uncertainty Finally, the designed controllers are realized by DSP, and these controllers are applied to a commercial DVD-ROM drive. From these experiments, we prove that the designed robust controllers have more good disturbance rejection performance and robustness when it is compared to the conventional lead-lag controller.

• 소음진동
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• 제9권2호
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• pp.324-330
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• 1999

With the increase of track density, high rotational speed and the compatibility for various media such as CD-ROM, CD-R/RW, DVD-ROM/RAM/RW etc. in optical disk drive, the effective anti-vibration design is so crucial for robust operaton. Especailly when the drive is self-excited by unbalanced disk, internal sled base vibration and its external transmission to the case bring about so severe problem. Generally these two consideration points the practical anti-vibration design process to control thses two conflictive properties using finite element analysis. As an example of the design process, Duro 25 and 40 visco-elastic rubber mount was selected and analyzed. The stiffness obtained from FEM rubber model was well matched with the experiments. Also it was confirmed that the internal and external vibration induced from unbalanced disk have good agreement with experimental results. The proposed design process is adopted to the slim-type optical disk drive.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1000-1003
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• 2002

For high density optical storage, there should be a high NA objective lens and a shorter wavelength laser diode. To secure the disc tilt margin related to the coma aberration, moreover, it's difficult to apply the tilt compensation mechanism into the portable PC. In this paper, we proposed the 3-axis asymmetry pickup actuator with high efficiency symmetric magnetic circuit, which consisted of the top cover type inner yoke for high magnetic flux density, the coil stack unit for the 3-axis independent operation and vertically polarized magnets. This newly suggested actuator features DVD-RAM recording, we achieved the high focus & track AC sensitivity and the greatly stabilized system.