• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.866-870
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• 2004

We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with rubbing alignment method on polyimide surfaces using plastic substrates. It was found that monodomain alignment of NLC is obtained with rubbing alignment method on polyimide surfaces using thin plastic substrates. The NLC pretilt angles on thin plastic substrates generated higher than that on glass substrate. Also, EO characteristics of the TN-LCD with a rubbed PI surface based on polymer substrate are almost the same as that of the TN-LCD with a rubbed PI surface based on glass. However, the transmittances of the TN-LCD with a rubbed PI surface based on polymer is less than that with a rubbed PI surface based on g1ass.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.170-174
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• 2017

In 3 electrode reflective displays using a plastic substrate, unstable packaging induces particle clumping and optical degradation due to external air inflow and electronic ink evaporation. In this work, we fabricate 3 electrode electronic paper using glass wafer, ITO/plastic film, and ITO/glass/gas barrier film as an upper substrate after injecting electronic ink onto the lower substrate. Then, we studied its properties. After operating under stress conditions for 336 hours at $85^{\circ}C$ and 75% humidity, the reflectivity of driven e-paper panels with white color was 25.5% for the panels using glass wafer, 22.5% for plastic film including a gas barrier layer, and 16% for plastic film only. From these optical properties, we conclude that gas barrier film improves upper film isolation as a desirable packaging method.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.25-28
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• 2000

In this paper, three types of organic electroluminescent devices(OELD) were fabricated on mechanically flexible plastic substrate by using vacuum deposition method. The devices consist of a hole transporting material such as TPD, a light-emitting material such as Alq$\sub$3/ and an electron transporting material, blocking material such as PBD. Electrical and optical properties of these OELDs were measured. This paper shows that organic small molecules based on OELD can be successfully deposited on a flexible plastic substrate. This points open the potential for low cost mass production of flexib]e displays, including roll to roll processing.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.87-92
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• 2009

Remote detecting system for a radiation contamination using a plastic scintillator and an optical fiber was developed. Using a commercially available silica optical fiber and a plastic scintillator, we tested then for a real possibility as a remote monitoring detector. Also, a plastic scintillator was developed by itself, and evaluated as a radiation sensor. The plastic scintillator was made of epoxy resin, a hardener and an organic scintillation material. The mixture rate of the epoxy resin, hardener and organic scintillator was fixed by using their emission spectrum, transmittance, intensity etc. In this study, in order to decrease the light loss of an incomplete connection between an optical fiber and a scintillator, the optical fiber was inserted into the scintillator during the fabrication process. The senor used a plastic optical fiber and was estimated for its detection efficiency by an optic fiber's geometric factor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.459-460
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• 2005

The global consumption of aspheric surfaces will expand rapidly on the Electronics and Optical Components, Information and Communications, Aerospace and Defense, and Medical optics markets etc. We must research on market, technology forecast and analysis of aspheric surfaces that is a principle step of ultra precision machine technology with a base one of optical elements. Especially, F-theta lens is one of the important parts in LSU(Laser scanning unit) because it affects on the optical performance of LSU dominantly. The core is most of important to produce plastic F-theta lens by plastic injection molding method, which is necessary to get the ultra-precision aspheric and non-axisymmetric machine processing technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.978-982
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• 2010

For mass information transfer, the optical communication using optic fiber has been widely used. Especially, in the field of medical image, the large data is digitalized based on the standard image and it is used for telemedicine with this method. Therefore, to transfer the large amount of data fast and effectively POF (Plastic Optical Fiber) can be used and the development of optic connector for connection between POFs is very important. In this study, for stable optical coupling of POF optic fiber Ferrule and Sleeve were designed and produced by considering the bond stability and the insertion loss according to the physical contact and roughness profile was evaluated. As a result of examining the insertion loss by physical contact method of two optic fibers, it showed the loss was about 1.895dB. According to the results from studying the condition of grinding section for POF mass production, the mass production condition was established as POF profile roughness of 6nm and the loss of 0.2dB or lower by controlling the film size and time step by step.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.185-189
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• 2002

Flexible displays such as plastic based LCDs and organic light-emitting diodes for mobile communication devices have been researched and developed at KETI in KOREA since 1997. The Plastic film substrate has so poor thermal tolerance and non-rigidness that the fabrication of active devices and panel assembly have to perform at low temperature and pressure. In addition, high thermal expansion of the substrate is also a serious problem for reliable metallic film deposition. In this paper, we investigated particularly on the fundamental characteristics of various plastic substrates and then, suggested novel methods that improve the fabrication processes of plastic LCD panel. In order to maintain stable substrate surface and uniform cell gap during panel assembly, we utilized newly-invented iii and vacuum chuck. Electro-optical characteristics of fabricated plastic LCD are better than or equivalent to those of typical glass based LCDs though it is thinner, lighter-weight and more robust.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04a
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• pp.18-22
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• 2004

We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with rubbing alignment method on polyimide surfaces using thin plastic substrates. It was found that monodomain alignment of NLC is obtained with rubbing alignment method on polyimide surfaces using thin plastic substrates. The NLC pretilt angles generated are about $3^{\circ}$ by the rubbing alignment method on thin plastic substrates, However, the pretilt angle are at about $1.7^{\circ}$ lower on the glass substrate than on thin plastic substrate. Also, EO characteristics of the TN-LCD with a rubbed PI surface based on polymer are almost the same as that of the TN-LCD with a rubbed PI surface based on glass. However, the transmittances of the TN-LCD with a rubbed PI surface based on polymer is less than that with a rubbed PI surface based on glass.

• Transactions of Materials Processing
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• v.18 no.2
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• pp.128-134
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• 2009

The present study covers an integrated simulation method to evaluate optical performance of an aspheric plastic lens by connecting an injection molding analysis with a ray tracing simulation. Traditional ray tracing methods have based on the assumption that the optical properties of a lens are homogeneous throughout the entire volume. This assumption is to a certain extent unrealistic for injection-molded plastic lenses because material properties vary at every point due to the injection molding effects. To take into account the effects of the inhomogeneous optical properties of the molded lens, a numerical scheme is developed to calculate the distribution of refractive index induced from the injection molding process. This index distribution is then reflected onto CODE $V^{(R)}$ simulation and used to calculate ray paths in inhomogeneous media. The proposed tracing scheme is implemented on the tracing of an aspheric lens for a mobile phone camera module.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.42-49
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• 2009

The optical elements made of plastics are normally produced by mass production such as injection molding with use of precision dies and molds. It costs to prepare the dies and molds, and it is only justified to prepare such expensive dies and molds when the parts are massively produced. On the other hand, it is too expensive and inefficient when precision plastic parts are needed only in small quantities, such as a case of trial manufacturing of new products. An ultra-precision diamond cutting is one of promising processes to produce the precision plastic parts in such cases. But it is commonly believed that an ultra-precision cutting of plastics for optical components is very difficult, because they are thermo-plastic material. In the present research, an ultra-precision diamond cutting of polycarbonate (PC), that is one of typical optical materials, was tried by using elliptical vibration cutting method. It is experimentally proved that good optical surfaces were obtained by using elliptical vibration cutting in cases of grooving and flat surfaces. The maximum surface roughness of less than 60 nm in peak to valley value is acquired.