• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.142-150
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• 2016

This paper developed new manufacture process technology of slim type flexible flat lighting product used lower power white LED. Flexible flat lighting is applied to letter sign lighting, traffic lighting, interior wall lighting, flat lighting, aquarium back lighting, wreath light etc. Main manufacture process technology were developed drawing software for electronics circuit, inkjet electronic circuit pattern and inkjet white ink coating. For pattern printing it was utilized for piezoelectonic inkjet head printing technology. Also high vacuum pressure laminating technology was waterproofing for LED flat lighting protection. Hence, form process technology we were manufactured for flexible flat lighting product of the power 12 W, input voltage 48 V and plane size $480{\times}480mm$. It acquired a these validity from experiment results.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.20-25
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• 2010

The effect of micro surface structure on printing for printed electronics has been studied experimentally. The photolithography MEMS fabricationwass used to make a SU-8 molder which has micro structures on the surface, and the PDMS micro structure was fabricated by the PDMS molding method. In the aspect of printed electronics, we used silver paste conductive ink. We measured the surface energy variation on pillar microstructure. The microstructure was used to real printing experiment by a screen printing. We printed 1cm micro lines which have $30{\sim}250{\mu}m$ width, and checked the conductivity to sort out opened line pattern. Printability was defined by success probability of printed patterns and we found that the present microstructures improve the printability significantly.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.686-686
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• 2013

Crystalline silicon solar cell is a semiconductor device that converts light into electrical energy. Screen printing is commonly used to form the front/back electrodes in silicon solar cell. Screen printing method is convenient but usually shows high resistance and low aspect ratio, which cause the efficiency decrease in crystalline silicon solar cell. Recently the plating method is applied in c-Si solar cell to reduce the resistance and improve the aspect ratio. In this paper, we investigated the effect of additional electroless Ag plating into screen-printed c-Si solar cell and compared their electrical properties. All wafers used in this experiment were textured, doped, and anti-reflection coated. The electrode formation was performed with screen-printing, followed by the firing step. Aften then we carried out electroless Ag plating by changing the plating time in the range of 20 sec~5 min and light intensity. The light I-V curve and optical microscope were measured with the completed solar cell. As a result, the conversion efficiency of solar cells was increased mainly due to the decreased series resistance.

• Journal of the Korean Society of Visualization
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• v.6 no.2
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• pp.39-44
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• 2008

The Roll-to-Roll system including continuous flexible thin materials and roller has its wide range of applications especially in the electronic printing industry. The industry is growing rapidly and the printing speed is also improving. However, the printing machine based on web and roller system has it own problem. As the web speed increases, the failure to maintain the contact may occur and the air entrain between the roller and the paper web may exist. Air bubbles may remain attached to electronic ink on the web causing defects on product surface. With the development of image processing technique, the airflow around the web and rolls can be visualized and calculated by PIV method. In our experiment, the simple web and rolls system is used to R2R simulator. The flow field is studied at various web speeds and positions. The result shows that the flow field has complicated structure with turbulent characteristic and the main trend of flow is obtained by taking time average of flow field.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.334-341
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• 2015

This paper summarizes the results of an investigation into the environmental factors that have an indirect impact on parts quality, as well as those process variables and modeling information that have a direct impact. The effects of strength, surface hardness, roughness, and accuracy of shape, that is, qualities that users generally need to know, were evaluated with laminating direction experimentally. The 3D printing methods used in this experiment were fused deposition modeling (FDM), stereolithography apparatus (SLA), selective laser sintering (SLS), 3D printing (3DP) and laminated object manufacturing (LOM). The goal was to achieve a high standard of quality control and product quality by optimizing the fabrication process.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2718-2722
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• 2008

The Roll-to-Roll system including continuous flexible thin materials and roller has its wide range of applications especially in the electronic printing industry. The industry is growing rapidly and the printing speed is also improving. However, the printing machine based on web and roller system has it own problem. As the web speed increases, the failure to wet the surface may occur and the air entrains between the liquid and the paper web. Air bubbles may remain attached to the paper web causing defects on product surface. With the development of image processing technique, the air airflow around the web and rolls can be visualized and calculated by PIV method. In our experiment, the simple web and rolls system is used to R2R simulator. The flow field is studied at various web speeds and positions. The result shows that the flow field has complicated structure with turbulent characteristic and the main trend of flow is obtained by taking time average of flow field.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.529-534
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• 2023

Although line printing technology is capable of high-speed and large area printing, residual stresses generated during the manufacturing process can deform the feedhole, causing nozzle plate crack or ink leaks. Therefore, in this paper, we propose a new thermal inkjet print head that is robust, reliable and more suitable for line-printing. The amount of deformation of the conventional line printing head measured through the experiment was converted into an equivalent load, and the validity of the load estimation method was verified through FEA analysis. In addition, in order to minimize deformation without increasing the head size, the head structure was designed to increase internal rigidity by reinforcing the unit nozzle with a pillar or support wall or by adding a support beam or dry/wet etched bridge. The FEA analysis results show that the feedhole deformation was reduced by up to 90%, and it is confirmed that the suggested print head with dry etched feedhole bridge operates normally without nozzle plate cracks and ink leakage through fabrication.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.10-21
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• 2021

Recently, the demand for atypical structures with functions and sculptural beauty is increasing in the construction industry. Existing mold-based structure production methods have many advantages, but building complex atypical structures represents limitations due to the cost and technical characteristics. Production methods using molding are suitable for mass production systems, but production cost, construction period, construction cost, and environmental pollution can occur in small quantity batch production. The recent trend in the construction industry calls for new construction methods of customized small quantity batch production methods that can produce various types of sophisticated structures. In addition to the economic effects of developing related technologies of 3D Concrete Printers (3DCP), it can enhance national image through the image of future technology, the international status of the construction civil engineering industry, self-reliance, and technology export. Until now, 3DCP technology has been carried out in producing and utilizing residential houses, structures, etc., on land or manufacturing on land and installing them underwater. The final purpose of this research project is to produce marine structures by directly printing various marine structures underwater with 3DCP equipment. Compared to current underwater structure construction techniques, constructing structures directly underwater using 3DCP equipment has the following advantages: 1) cost reduction effects: 2) reduction of construct time, 3) ease of manufacturing amorphous underwater structures, 4) disaster prevention effects. The core element technology of the 3DCP equipment is to extrude the transferred composite materials at a constant quantitative speed and control the printing flow of the materials smoothly while printing the output. In this study, the extruding module of the 3DCP equipment operates underwater while developing an extruding module that can control the printing flow of the material while extruding it at a constant quantitative speed and minimizing the external force that can occur during underwater printing. The research on the development of 3DCP equipment for printing concrete structures underwater and the preliminary experiment of printing concrete structures using high viscosity low-flow concrete composite materials is explained.

• Journal of Conservation Science
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• v.37 no.3
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• pp.289-301
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• 2021

When investigating old, printed documents, determining whether a work is printed on a woodblock or using a movable metal type is crucial. It is because the history of printing in Korea and across the world relies on determining the relevant printing invention used and the time of use of the movable metal type. Deciphering details from woodblock and metal prints requires various kinds of information regarding the imprint and the work's printing background, such as information on the characters in the printed document, the outline of the pages, the type of ink used, the production period of the ink, and the production period of the Korean paper. Analyzing such information can generally reveal the production period and the methods used on the old document. However, as such information is not documented systematically, relying on the researcher's judgment based on their experience and perception becomes inevitable. This study conducted an experimental investigation of the printing characteristics of woodblock prints using a replicated woodblock of the Wanpanbon edition of the Shimcheongjeon. Subsequently, the various phenomena and characteristics appearing on the woodblock prints were documented for future reference to determine the printing method of old documents. Finally, woodblock novels without an imprint may be used as a reference to estimate the printing dates by determining the degree of wear on the woodblock.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.84.2-84.2
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• 2010

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active components in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT, which are printed with functional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manufacturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem: it is difficult to apply toa continuous process as a R2R printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, anelectrostatic atomizer sprays micro-drops from the solution injected into the capillary, with electrostatic force generated by electric potential of about tens of kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and Active layer which consist of the P3HT:PCBM. The result of experiment, organic solar cell using ESD thin film coated method is occurred efficiency of about 1.4%. Also, the case of only used to ESD method in the active layer coating is occurred efficiency of about 1.86% as the applying a spin coating in the PEDOT:PSS layer. We can expect that ESD method is possible for continuous process to manufacture in the organic solar cell or OLED device.