• 한국전산유체공학회:학술대회논문집
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• 1998.11a
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• pp.48-54
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• 1998

Three-dimensional incompressible Navier-Stokes equations have been solved by the node-centered finite volume method with unstructured hybrid grids. The pressure-velocity coupling is handled by the artificial compressibility algorithm and convective fluxes are obtained by Roe's flux difference splitting scheme with linear reconstruction of the solutions. Euler implicit method is used for time-integration. The viscous terms are discretised in a manner to handle any kind of grids such as tetrahedra, prisms, pyramids, hexahedra, or mixed-element grid. The numerical efficiency and accuracy of the present method is critically evaluated for several example problems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.56-61
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• 2003

This paper described about on-machine profile measurement of aspheric surfaces using contact probing technique in ultra precision machine. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime using a circle leaf spring mechanism and a capacitive-type sensor. The contact probe which is installed on the z-axis is In touch with the aspheric objects which is fixed on the spindle of the diamond turning machine(DTM) during the measuring procedure. The x, z-axis motions of the machine are monitored by a set of two orthogonal plane mirror type laser interferometers. As a results, the developed contact probe on-machine measurement system showed 10 nanometers repeatability with a ${\pm}2{\sigma}$ and uncertainty of 200 nmPv.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.3
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• pp.3-8
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• 2007

This study is for aspheric lens that is one of a core technology in the optical industry. The feature of a aspheric lens is not to have the spheric aberration. So in optical industry, aspheric lens are essential element to miniaturization, high effectiveness and light weight. In this study we applied a lay back-tracer method using the index of refraction to design aspheric lens. We developed the automatic design program for aspheric lens by user interfacing program VisualLISP in AutoCAD. And we manufactured aspheric lens and measured it.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.7-12
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• 2007

The optic industry is a high value-added advanced technology industry combined with the precision machine industry and the digital electronics industry. The aspheric lens, one of optic parts, is a key technology having a significant influence on the performance of optic equipment. So this study relates to designing an aspheric lens to which a ray-tracing method is applied. In the ray-tracing method, a refractive index of material is used, which take an advantage that the location of a light source and incident angle can be fixed, unlike the ray back-tracing scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.891-894
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• 1997

The asphericals lenses are used as objective lens of optical pickup. To examine the design factor the sample product is made before manufacturing of injection mould of lens. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, he main spindle sped, the depth of cut, the feedrate are found. The demanded surface roughness 10nm Ra, aspherical form error 0.5${\mu}{\textrm}{m}$ P-V for aspherical lens of optical data storage device are satisfied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.90-93
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• 2003

This paper described about the ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a circle leaf spring mechanism and a capacitive-type sensor. The, contact probe is attached on the z-axis during measurement while aspheric object are supported on the diamond turning machine(DTM). The machine xz-axis motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed of on-machine measurement system in this investigation is capable of providing a repeatability of 10 nanometers with a $\pm$20 uncertainty of 200nmPv.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.525-528
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• 2003

The aspherical lens are used as objective lens of optical pickup. The sample product is made before manufacturing the injection mould of lens to examine the design factor. The optimum cutting conditions of the main spindle speed, the depth of cut, the feed rate are found when we cut PMMA and PC lens sample with ultra-precision SPDT. The demanded surface roughness 10 nm Ra. aspherical form error 0.5 ${\mu}{\textrm}{m}$ P-V for aspherical lens of optical data storage device are satisfied for PMMA. but not satisfied for PC.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.323-324
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• 2006

This study is described the modeling of aspheric lens, manufacturing and inspection. The aspheric lens is different from a convex lens and concave lens in that is useful to aspherical, but modeling mettled of this isn't open to the public. Therefore, This study is designed to the aspheric lens of geometric form, manufactured a sample by CAM which is applied to Euler method. So, we have verified modeling and CAM process for aspheric lens through a experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.644-647
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• 2003

Resulting from reproducibility and possibility of mass production. many researches to fabricate micro lens array using lithography have been developed. However, it still remains the level of fabricating compensation lens. Therefore, to realize the fabrication of lens having high numerical aperture can be the key technology of ultra slim optical system. Reflow phenomenon have been researched to make lens having high refractive power. And through those researches, the possibility to fabrication of high refractive power lens has been investigated. In this paper, we analyze the effect of many parameters in reflow process to get an aspheric shape with high repeatability. And we make possible to estimate shape error, through we give direct information about decrease in volume of photoresist.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.603-606
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• 2000

This dissertation is concerned with ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a leaf spring mechanism and a capacitive-type sensor. The contact probe is attached on the z-axis during measurement while aspheric objects are supported on an precision xy-stage whose lateral motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed in this investigation is capable of providing a repeatability of 50 nanometers with a $\pm$3$\sigma$ uncertainty of 300 nanometers. Thermal disturbance is found the most significant factor that should be precisely controlled for accurate measurement.