• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.25-32
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• 2003

Molding properties of etched surface pattern are presented. Injection molding has given attention on improving dimensional accuracy and productivity. However, the molding of etched surface pattern on plastic parts is not researched relatively for its additional values, which can meet design function and customer's attraction. Specimens, whose surface patterns are made by print-type etching, are investigated. The molding properties of surface pattern are estimated with roughness deviation of surface pattern on part and mold. The etching properties are related to physical properties of plastic materials and surface roughness of etched pattern. Also, flow mark and gate location can give influence on surface pattern molding. The experimental result can contribute to good molding of surface pattern in injection molding.

• 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 Society of Precision Engineering Conference
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• 2002.05a
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• pp.583-586
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• 2002

Molding properties of etched surface pattern are presented. Specimens, whose surface patterns are made by print-type etching, are investigated. The molding properties of surface pattern are estimated with roughness deviation of surface pattern on part and mold. The etching properties are related to physical properties of plastic materials and surface roughness of etched pattern. Also, flow mark and gate location can give influence on surface pattern molding. The experimental result can contribute to good molding of surface pattern in injection molding.

• The Journal of Korean Academy of Prosthodontics
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• v.23 no.1
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• pp.83-95
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• 1985

The purpose of this study was to evaluate microstructures on the etched surface of 11 base metal alloys for dental restorations and to observe the relationship between the etching pattern and beryllium. For this purpose, the following experiments were done; 11 base metal alloys were etched in (1) 10% $H_2SO_4$, (2) 10% $H_2SO_4$, 9 parts+methanol 1 part (3) Conc. $HNO_3$ 25%+glacial acetic acid 25%+$H_2O$ 50% (4) Conc. $HNO_3$ 5% (5) 2% glacial acetic acid added to Conc. $HNO_3$ 1% solution, with their etching conditions varied. Etched surface of alloys were examined under the scanning electron microscope. Results were as follows; 1. Almost all of Ni-Cr-Be alloys showed gooed etchd surface in $H_2SO_4$, solution, while some of those alloys which contains no beryllium showed good etched surface in $HNO_3$ solution. 2. Main components of etching solution can vary etching pattern of alloys. 3. Gamma prime phase relief, which can be found in all Ni-Cr-Be alloys, can't be found in any alloy that contains no beryllium.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3280-3286
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• 2009

In this paper, we designed and manufactured HD Switch Panel parts with micro-etched pattern. By using CAE analysis, we could predict weld-line positions and the amount of shrinkage during injection molding process. We measured the temperature distribution of the mold surface so that we could optimize the processing conditions such as mold temperature. In order to increase the transcription of micro-etched pattern, we applied the E-Mold technology and evaluated the effect of mold temperature on the surface quality. We concluded that the etched pattern was improved(more than 2.5$\to$1.5~1.7) through the measurement of surface gloss and the observation of both SEM and SPM images.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.397-402
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• 2017

We used an etching process to control the line-width of screen printed Ag paste patterns. Ag paste was printed on anodized Al substrate to produce a high power LED. In general, Ag paste spreads or diffuses on anodized Al substrate in the process of screen printing; therefore, the line-width of the printed Ag paste pattern increases in contrast with the ideal line-width of the pattern. Smudges of Ag paste on anodized Al substrate were removed by neutral etching process without surface damage of the anodized Al substrate. Accordingly, the line-width of the printed Ag paste pattern was controlled as close as possible to the ideal line-width. When the etched Ag paste pattern was used as a seed layer for electroless Ni plating, the line width of the plated Ni film was similar to the line-width of the etched Ag paste pattern. Finally, in pattern formation by Ag paste screen printing, we found that the accuracy of the line-width of the pattern can be effectively improved by using an etching process before electroless Ni plating.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.85-93
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• 1983

In one group that tested for the effects of grinding and etching on the deciduous teeth, S.E.M. examination on the ground or unground labial surface of deciduous maxillary central incisors were made after etching procedure with 40% phosphoric acid for 60 secs., 120 secs., 180 sees. each. In another group that tested for the degree of resin penetration to the ground and etched deciduous teeth, composite resin application was done to the ground deciduous maxillary central incisors that had been acid-etched for 30 secs., 60 secs., 90 sees., 120 sees., 180 secs. each. The tooth-resin specimens were cut at the middle 1/3 of the crown by 2mm thickness, and the adjacent tooth materials were demineralized by 10% hydrochloric acid, the author observed the tags of the resin replica with S.E.M.. Following results were obtained. 1. After 40% phosphoric acid etching, the unground deciduous enamel surface showed various types of etching pattern. 2. For the formation of regular micropores on deciduous enamel surface by acid etching with 40% phosphoric acid, the time over 120 secs. should be requested. 3. After 40% phosphoric acid etching, the ground deciduous enamel surface showed the same etching pattern that has been a preferential removal of prism peripheries despite different etching time. 4. On the ground group that etched over 60 secs. to 180 secs., the length of tags was $5{\mu}m$ to $8{\mu}m$, with a mean of $7{\mu}m$.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.398-400
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• 1998

In this paper, the etching studies for n-GaN were carried out using the wet chemical, the photo-enhanced-chemical, and the electro-chemical etching methods. The experimental results show that n-GaN is etched in diluted NaOH solution at room temperture and the etched thickness of NaOH and electron concentrations. Te etching rate of n-GaN samples with n.simeq.1*10$^{19}$ cm$^{-3}$ were used to compare the photo-enhanced-chemical etching with the electrochemical etching methods. The removed thickness was 680.angs./25min by the electrochemical etching methods. The removed thickness was 680 .angs./25min by the electrochemical etching method ad 784.angs./25min by the photoenhanced-chemical etching method. The patterns are 100.mu.m*100.mu.m rectangulars covered with SiO$_{2}$film. It is shown that the profile of etched side-wall of the pattern is vertical without dependance of the n-GaN orientations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.654-658
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• 2009

For investigation of surface leakage currrent of AlGaN/GaN heterostructures through etched GaN buffer surface and mesa wall, three kind of surface-leakage-test-patterns were fabricated. and we measured the surface leakage current of each patterns. In result of our work, the surface leakage current of pattern of which Schottky contact is formed on etched mesa wall is the largest. the leakage current through schottky contact on etched mesa wall is predominant in AlGaN/GaN heterostructures.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.1
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• pp.52-62
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• 2003

In this paper, photonic bandgap(PBG) bandstop filters which are composed of periodically etched circles in the ground plane show good microwave characteristics with the harmonic suppression on stopband. The PBG structures were analyzed using a finite-difference time-domain(FDTD) simulation and experimental measurement. The FDTD technique is used because it can simulate arbitrary 3-D structures and provide broadband frequency response. The analysis results are presented it is the same that only one row of etched circles and 2-dimension three rows of etched circles. And we show the PBG resonator characteristics between etched circles using field pattern and frequency characteristics as functions of etched circle number n, etched circle radius r and period a.