• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.3.1-3.1
• /
• 2011

Over the past decade, the major efforts for lowering the cost of electronics has been devoted to increasing the packaging efficiency of the integrated circuits (ICs), which is defined by the ratio of all devices on system-level board compared to the area of the board, and to working on a larger but cheaper substrates. Especially, in flexible electronics, the latter has been the favorable way along with using novel nanomaterials that have excellent mechanical flexibility and electrical properties as active channel materials and conductive films. Here, the tool for achieving large area patterning is by printing methods. Although diverse printing methods have been investigated to produce highly-aligned structures of the nanomaterials with desired patterns, many require laborious processes that need to be further optimized for practical applications, showing a clear limit to the design of the nanomaterial patterns in a large scale assembly. Here, we demonstrate the alignment of highly ordered and dense silicon (Si) NW arrays to anisotropically etched micro-engraved structures using a simple evaporation process. During evaporation, entropic attraction combined with the internal flow of the NW solution induced the alignment of NWs at the corners of pre-defined structures. The assembly characteristics of the NWs were highly dependent on the polarity of the NW solutions. After complete evaporation, the aligned NW arrays were subsequently transferred onto a flexible substrate with 95% selectivity using a direct gravure printing technique. As proof-of-concept, flexible back-gated NW field effect transistors (FETs) were fabricated. The fabricated FETs had an effective hole mobility of 0.17 $cm2/V{\cdot}s$ and an on/off ratio of ${\sim}1.4{\times}104$. These results demonstrate that our NW gravure printing technique is a simple and effective method that can be used to fabricate high-performance flexible electronics based on inorganic materials.

• The monthly packaging world
• /
• s.114
• /
• pp.56-62
• /
• 2002

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.12
• /
• pp.1017-1023
• /
• 2007

This study is intended to analyze the effect of thin ink-film thickness around rotating printing roll on the printing quality in the gravure printing process which is used for making electronics circuit like a RFID tag with a conductive ink. The present work numerically estimates the film thickness around rotating roller partially immersed in ink for which the volume of fluid (VOF) method was adopted to figure out the film formation process around rotating roller. Parameter studies were performed to compare the effect of ink properties (viscosity, surface tension), operating condition (roller rotating speed, initial immersed angle) on the film thickness. The result indicates that the film thickness has a strong dependency on the rotating speed, while the surface tension has negligible effect.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.2
• /
• pp.51-57
• /
• 2010

The shape of the register mark for the image processing becomes very important, because the printing quality is determined by the error correction between the register marks for the image processing. In this paper, printing marks are developed using the image process for the gravure printing method which is commonly being used in roll to roll, high resolution printing. The marks which can be cited to the flexible display print are developed The developed register marks which satisfies 10[${\mu}m$] error tolerance are tested under 70[mpm] printing conditions and confirmed through the experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.645-646
• /
• 2013

• The monthly packaging world
• /
• s.214
• /
• pp.113-137
• /
• 2011

한국포장기술인협의회는 지난 해 10월 22일 서울 팔래스호텔 로얄볼룸에서 제26회 한국포장기술인 세미나를 개최했다. 이날 세미나는 '라미네이트용 수성접착제 기술과 적용 방법 및 일본인쇄산업연합회의 Gravure인쇄 Service(연포장) Green 기준 가이드 라인'을 주제로 진행됐다. 본 원고는 세미나에서 김영호 한국포장기술인협의회 회장이 발제한 자료로, 지난 1월호에 이어 인쇄 Service Green 기준과 Green Printing 인정제도, Gravure 인쇄 Service(연포장) Green 기준 및 해설에 대해 살펴보도록 한다.

• The monthly packaging world
• /
• s.213
• /
• pp.104-132
• /
• 2011

한국포장기술인협의회는 지난 해 10월 22일 서울 팔래스호텔 로얄볼룸에서 제26회 한국포장기술인 세미나를 개최했다. 이날 세미나는 '라미네이트용 수성접착제 기술과 적용 방법 및 일본인쇄산업연합회의 Gravure인쇄 Service(연포장) Green 기준 가이드 라인'을 주제로 진행됐다. 본 원고는 세미나에서 김영호 한국포장기술인협의회 회장이 발제한 자료로, 인쇄 Service Green 기준과 Green Printing 인정제도, Gravure 인쇄 Service(연포장) Green 기준 및 해설에 대해 상세히 설명하고 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.81-82
• /
• 2010

• Korean Chemical Engineering Research
• /
• v.53 no.1
• /
• pp.111-115
• /
• 2015

To produce patterns with high resolution in gravure printing, it is important to increase ink transfer ratio. The ink which has higher affinity with substrate can be transferred more from the roll to the substrate due to the good wettability between ink and substrate. However, it is difficult to evaluate the affinity between the substrate and the ink which is viscoelastic in nature. In this study, we suggest a practical method to evaluate the interfacial interaction between the ink and various substrates.

• International Journal of Precision Engineering and Manufacturing
• /
• v.3 no.1
• /
• pp.26-32
• /
• 2002

Laser direct patterning of the coated photoresist (PMER-NSG31B) layer was studied to make halftone dots on the gravure printing roll. The selective laser hardening of the photoresist by Ar-ion laser(wavelength: 333.6∼363.8 nm) was controlled by the A/O modulator. The coating thickness in the range of 5∼11㎛ could be obtained by using the up-down directional moving device along the vertically located roll. The width, thickness and hardness of the hardened lines farmed under the laser power of 200∼260mW and irradiation time of 4.4∼6.6 $\mu$ sec/point were investigated after developing. The hardened width increased as the coating thickness increased. Though the hardened thickness was changed due to the effect of the developing solution, the hardened layer showed good resistance to the scratching of 2H pencil. Also, the hardened minimum line width of 10㎛ could be obtained. The change of line width was also found after etching, and the minimum line widths of 6㎛ could be obtained. The hardened lines showed the good resistance to the etching solution. Finally, the experimental data could be applied to make gravure halftone dots using the developed imaging process, successfully.