• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.30-33
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• 2003

In this paper the advantage of web technology applied to Rapid Prototyping is discussed. Two fabrication processes are chosen to be web-enabled. One, a post-process of FDM is developed to provide translucent plastic parts made of medical grade ABS material. The other, a system to fabricate laser machined Light Guide Panel is developed. In order to show the timesaving characteristics of the web-based tools, two websites are implemented (http://nano.gsnu.ac.kr/fdm ＆ http://nano.gsnu.ac.kr/laser). The 3-tier architecture is applied for the Internet communication between designers and manufacturing sites, The integrated design tools and physical manufacturing processes enable designers to submit a new design and to receive the fabricated parts in an expedited manner. Example parts are fabricated using the web-based system to prove the concept of the web-based design and Rapid Prototyping.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.31-38
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• 2009

To improve the image quality and lower the power consumption of the mobile applications, it is the one of the best candidate to control the backlight unit of the LCD module with ambient light. Ambient light sensor and readout circuit were integrated in LCD panel for the mobile applications, and we designed them with LTPS TFT. We proposed noble start-up correction in order to correct the variation of the photo sensors in each panel. We used time-to-digital method for converting photo current to digital data. To effectively merge time-to-digital method with start-up correction, we proposed noble dual slope correction method. The entire readout circuit was designed and estimated with LTPS TFT process. The readout circuit has very simple and stable structure and timing, so it is suitable for LTPS TFT process. The readout circuit can correct the variation of the photo sensors without an additional equipment, and it outputs the 4-levels digital data per decade for input luminance that has a dynamic range of 60dB. The readout rate is 100 times/sec, and the linearity error for digital conversion is less than 18%.

• ETRI Journal
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• v.41 no.1
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• pp.23-31
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• 2019

Since the late 20th century, there has been rapid development in the display industry. Only 30 years ago, we used big cathode ray tube displays with poor resolution, but now most people use televisions or smartphones with very high-quality displays. People now want images that are more realistic, beyond the two-dimensional images that exist on the flat screen, and digital holography-one of the next-generation displaysis expected to meet that need. The most important parameter that determines the performance of a digital hologram is the pixel pitch. The smaller the pixel pitch, the higher the level of hologram implementation possible. In this study, we fabricated the world-smallest $3-{\mu}m$-pixel-pitch holographic backplane based on the spatial light modulator technology. This panel could display images with a viewing angle of more than $10^{\circ}$. Furthermore, a comparative study was conducted on the fabrication processes and the corresponding holographic results from the large to the small pixel-pitch panels.

• Advanced Industrial SCIence
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• v.1 no.1
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• pp.16-22
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• 2022

Starting with cathode ray tubes, displays are forming markets in the order of active marix organic light emitting diode (AMOLED) after PDP (Plasma Display Panel) and LCD (Liquid Crystal Display). OLED is recognized as a key field for the development of each country preparing for the fourth industrial revolution, and especially Samsung Display and LG Display, which are the top industries in Korea, are leading the market with more than 90% of OLED shares. Currently, AMOLED has moved to the area that can be folded or bent. This technology is possible because TFT (Thin Film Transistor) and OLED may be formed on a flexible substrate. In the future, the technology will move to stretchable displays, and for this, the development of substrate materials is first, and then TFT and OLED devices should also be implemented with stretchable materials.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.14-24
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• 2000

In present research, the plywoods made of radiata pine or Japanese larch, the potential softwood species in mass supply, were discussed to examine their feasibility as the structural and concrete form panels through the basic properties test. First, plywood qualities and its nail performance were tested. The performance test for concrete form or structural panel by concentrated and uniformly distributed load were conducted to investigate the possibility as structural material for light frame and concrete constructions. Test results of basic quality such as specific gravity, cupping, bowing, and twisting appeared to satisfy the criteria for structural use. Also, nail performance test results, for roof and wall sheathing panels, nail lateral resistance, nail withdrawal resistance, and nail push head resistance proved to meet the required standard for structural use. The test results on performance as structural panel by concentrated and uniformly distributed load and as concrete form panel showed that these two species could be used for structural sheathing, subfloor, and concrete form panels.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.69-84
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• 2011

This paper presents the applicability of NATM Composite Lining method in domestic tunnel construction sites. Firstly, in order to produce high quality PC Panel, optimal steam curing condition is reviewed. And in preparation for fire inside the tunnel, the fire-resistance test of PC Panel is carried out. The constructability of NATM Composite Lining method and the drainage ability of light-weight foamed mortar is also evaluated through field construction test. And PC Panel combination program is developed to calculate the quantity of PC Panel efficiently. Besides, economic evaluation for NATM Composite Lining method is conducted. From this research, it is clearly found that NATM Composite Lining method is applicable to domestic tunnel construction site.

• Composites Research
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• v.33 no.3
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• pp.140-146
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• 2020

The purpose of this paper is to examine the possibility of weight reduction by changing the partition panel of vehicle from an existing aluminum material to carbon fiber reinforced plastics. Three weaving methods (plain, twill and satin) were used in the manufacture of composite materials, and they were produced and tested to derive their material properties. The analysis model of composite partition panel for torsional conditions was developed and the structural stability and system stiffness were evaluated according to Tsai-Hill failure criteria. With design variables for fiber orientation angles and stacking sequence, evolutional optimal algorithm was performed and as the results, the optimal composite partition panel was designed. In addition, the structural analysis results for strength and specific stiffness were compared with aluminum partition panels and composite partition panels to verify the possibility of weight reduction.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.121-128
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• 2002

A new high-efficient energy-recovery circuit is proposed to drive a plasma display panel (PDP) and compared with the conventional circuit. The proposed circuit uses only two inductors and no auxiliary circuit to recover the energy stored in the equivalent intrinsic capacitance of PDP. Therefore it features a simpler structure, less mass, lower cost of production, higher efficiency, and fewer power devices. The very stable and uniform light emitted from PDP proves the high quality of screen. It is suitable for wall-hanging color TVs. The proposed circuit, operating at 200kHz, is verified to be applicable on a 42-inch PDP by experimental results.

• Structural Engineering and Mechanics
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• v.47 no.5
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• pp.623-641
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• 2013

The fiber-reinforced polymer (FRP) composite panel, with the benefits of light weight, high strength, good corrosion resistance, and long-term durability, has been considered as one of the prosperous alternatives for structural retrofits and replacements. Although with these advantages, a further application of FRPs in bridge engineering may be restricted, and that is partly due to some unsatisfied thermal performance observed in recent studies. In this regard, Kansas Department of Transportation (DOT) conducted a field monitoring program on a bridge with glass FRP (GFRP) honeycomb hollow section sandwich panels. The temperatures of the panel surfaces and ambient air were measured from December 2002 to July 2004. In this paper, the temperature distributing behaviors of the panels are firstly demonstrated and discussed based on the field measurements. Then, a numerical modeling procedure of temperature fields is developed and verified. This model is capable of predicting the temperature distributions with the local environmental conditions and material's thermal properties. Finally, a parametric study is employed to examine the sensitivities of several temperature influencing factors, including the hollow section configurations, environmental conditions, and material properties.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1034-1037
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• 2004

In this paper we fabricated a test panel for AMOLED on glass and PET substrate. The test panel consisted of the various size of OTFTs and OLEDs and the current driving capability of OTFTs for OLEDs has been investigated. OTFTs were made of the inverted staggered structure and employed polyvinylphenol (PVP) as the gate insulator and pentacene thin film as the active layer. The OTFTs produced the filed effect mobility of 0.3$cm^2$/V.sec and on/off current ratio of $10^5$. OLEDs consisted of TPD for HTL and Alq3 for EML with 35nm thick, generating green monochrome light. We found that OTFT with channel length of 70${\mu}m$and channel width of over 3.5mm provided the sufficient current to OLED to generate the luminescence of 0.3Cd/$m^2$.