• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.772-778
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• 2003

Polystyrene foam is easily melted and vapoured by heat, has a proper quality in the pattern manufacturing and has a low price. The objective of this study is to develop a rapid prototyping method fur polystyrene foam pattern manufacuring to use the eliminative pattern casting (EPC). Applying fur the rapid prototyping concept reversely, the unnecessary part of section is vapored away by heat source of laser beam. In order to examine the applicability between laser beam process and polystyrene foam material, the basic experiments such as hole, line, plane and contour process are carried out. With these results, various three-dimensional shape patterns are made and this rapid prototyping tool for polystyrene foam manufacturing.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.185-192
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• 1995

In this study, very fine photoresist pattern was examined using the image reversal process. And very fine photoriesist pattern (less than 0.2um) was obtsined by optimizing the exposure and reversal baking condition of photoresist. The produced pattern does not show the loss of thickness, and has a sparp negative edge profile. also, the ion implanted 0.25um T-shaped gate MESFET was fabricated using this resist pattern and the directional evaporation of gate metal. The fabricated MESFET has the maximum transconductance of 302 mS/mm, and the threshold voltage of -1.8V, and the drain saturation current of this MESFET was 191 mA/mm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.17-23
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• 1984

A model analysis of pattern shift in the epitaxial growth of silicon on (111) substrates was performed. The growth rate anisotropy was considered as the most important affecting factor of pattern shift, and for the model establishment the off angle of the substrate and the process temperature were taken as the variables. We derived a theoretical equation of pattern shift by assuming the growth rate anisotropy as the trigonometric sine function of the off angle of the substrate and defining the growth rate anisotropy factor related to the process temperature. The pattern shift ratio calculated by this model had the same tendency with the experimental ones, which, however, were about twice greater than those. It was supposed that this discrepailcy was due to the second order affecting factor such as facetting and step broadening which had been exluded in model establishment.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.239-242
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• 2003

Optical module package is a hermetic metal-ceramic package for carrying optical IC. In case of LD(laser diode) module, window is used for both the path of optical signal and hermetic sealing of package. So, window has the metallization pattern on the surface for brazing process with package wall. In this study, several method were investigated for metallization. Thin film, thick film and mixed method were used for fabrication of metallization pattern. After brazing process, hermeticity and adhesion strength were tested for characterization of metallization pattern.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.157-166
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• 2001

In general, the cutting pattern of the membrane structures is determined by dividing the complicated curved 3-D surface into several 2-D plane strip by using flattening technique. In this procedure, however, some discrepancies ore occurred between actual stresses of equilibrated state and designed uniform stresses because the material properties are not considered. These deviations can cause the critical structural problems, wrinkling or overstress, and thus a optimization process should be considered. In this paper, a new analytical method for determining an optimum cutting pattern considering material properties is presented. Here, iterative procedure is introduced to decrease the errors caused in numerical process. The optimization method proposed can diminish the deviations occurred by material properties and numerical errors, simultaneously. As a results, it is shown that the final stress distributions for the HP shell model are sufficiently near to design stress distributions, and it can be concluded that this method can be used to obtain the optimized cutting pattern of membrane structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.451-455
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• 1997

The partial discharge has been blown as the chief breakdown of power equipments. The analysis and the recognition is much difficult because the partial discharge signal is very small and has complex aging pattern. Recently, insulation aging diagnosis based on pattern of phase(Ф), partial discharge magnitude(q), number(n) has been very important. Owing to depreciate the reappearance of aging progress at the electrical tree pattern and to be difficult to analyze visually, the study on partial discharge pattern is suggested to normalizing analysis method of partial discharge signals. This parer is purposed on prediction of life-time measurement of cv-cable, on decision of risk degree with normalization and real-time measurement of partial discharge signals for aging diagnosis of cv-cable. As normalizing the aging signals of electrical tree in cv-cable, it is able to confirm risk degree of insulation material with the distribution of Ф-q-n and recognize the process of aging pattern using neural network.

• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.165-169
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• 2007

The light guide plate (LGP) of LCD-BLU (Liquid Crystal Display-Back Light Unit) is usually manufactured by forming numerous dots by etching process. However, the surface of those etched dots of LGP is very rough due to the characteristics of etching process, so that its light loss is relatively high due to the dispersion of light. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched-dot patterned LGP, micro-lens pattern was tested to investigate the possibility of replacing etched pattern in the present study. The micro-lens pattern fabricated by the modified LiGA with thermal reflow process was applied to the optical design of LGP. The attention was paid to the effects of different optical pattern type (i.e. etched dot, micro-lens). Finally, the micro-lens patterned LGP showed better optical qualities than the one made by the etched-dot patterned LGP in luminance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.416-417
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• 2007

MmSH injection molding method to fabricate light guiding plate with nano-sized pattern was developed. A stamper was fabricated through photolithography, dry etching, and electroplating processes. While the stamper with nano-sized pattern in mold was kept at $180^{\circ}C$ during injection process, that was cooled down to $90^{\circ}C$ quickly after the injection process. The nano-sized pattern on light guiding plate processed by MmSH injection molding method was well transferred from stamper compared to that processed by conventional injection molding process.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.2
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• pp.63-67
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• 2018

Recent mold industry uses many roll-to-roll processes that can produce high production speed and precision machining and automation process. In the circular cylinder mold, however, patterns of less than $10{\mu}m$ are difficult to manufacture and maintain. In this study, we fabricated a circular cylindrical mold with a DLC thin film which have high hardness, low coefficient of friction and high releasability by using lithography and lift-off process. The height, line width, and pitch of the fabricated DLC macro pattern are $3.1{\mu}m$, $9.1{\mu}m$ and $20.2{\mu}m$, respectively. The pattern size is finer than the current applied to the aluminum cylinder type, and this shows the possibility of practical use of DLC micro pattern roll mold.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.239-244
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• 2011

Nano Imprint Lithography(NIL) is technique for copying a pattern from stamp with nano size pattern in order to replicated the materials. It is very important to demold in order to make NIL process effectively. Self Assembled Monolayers(SAM) coater is manufactured by means of decreasing surface energy with the stamp surface treatment to improve release characteristics. Manufactured device contains tilting and rotation option for increasing process life time by coating on the sidewall of the pattern in stamp. The stamp coated with optimized tilting angle $30^{\circ}$ and rotation speed of 10rpm has more imprinting cycles than the stamping coated without tilting and rotation. Effective SAM coating on the sidewall of the pattern in stamp will improve by 50% of process life time.