• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.63-64
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• 2008

Electrokinetic motion of fullerene ($C_{60}$) particles in liquid crystal (LC) medium under an in-plane electric field has been studied for the application to the electronic paper display. Fullerenes move in the direction of applied electric field due to interaction between the induced dipole moment on $C_{60}$ and external electric field at lower threshold voltages compared to other devices such as QR-LPD (Quick Response Liquid Powder Display) and TBD (Twisting Ball Display). We also confirmed the bistability of fullerene particles in LC medium and the results showed that the 87% and 81% of original reflectance or transmittance of image was retained after 24 hours and 48 hours respectively. Our studies show the possibility that fullerenes can be used for electronic paper display.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.629-631
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• 2004

We report on the synthesis and film formation on a variety of small molecules such as $Alq_3$, $Znq_2$, and $Inq_3$, used as light emitting material in organic light emitting diodes (OLEDs) . The organic materials are usually susceptible to environmental aging and photo-oxidation, which influences their viability for commercial utility. Here, we examine the effects of oxygen and light on these organic materials to enhance the efficiency and lifetime of OLEDs. Optical techniques - ellipsometry, photoluminescence and infrared spectroscopies- have been used to study of environmental and light induced effects on 8-hydroxyquinoline derivative metal complex small molecules thin films

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.220-224
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• 2005

The technology trend of Flat Panel Display (FPD) equipments have been demanded that there are compact and multi-function. Therefore, nano/micro scale patterned on polymeric materials of Back Light Unit (BLU) in Liquid Crystal Display (LCD) that has been investigated. This paper describes a series of Horizontal Type Micro Tensile Tester that were carried out to investigate the load strain distance performance of typical polymeric material sheets. The polymeric materials film that micro size shaped specimens for tensile test are used by Cold-Isostatic-Press (CIP). Test equipment is Horizontal type Micro Tensile Tester that is presented to measure the micro scale mechanical property of thin film for FPD. This paper presents which easy testing tools measure for micro patterned on polyethylene (PET) specimens.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.234-234
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• 2003

Indium tin oxide(ITO) is an advanced ceramic material with many electronic and optical applications due to its high electrical conductivity and transparency to light ITO thin films are used in transparent electrodes for display devices, transparent coatings for solar energy heat mirrors and windows films in n-p heterojunction solar cells, etc. Almost all display devices were fabricated on transparent ITO electrode substrates. There are several factors that cause decay in the efficiency and the failure of display devices. The degradation or damage of ITO is one of the main factors. Under normal operating conditions, the electric fold required for the operation of display devices is very high As a high electric field induces the joule heat, the degradation of the ITO thin film may be expected. Therefore, it is worthy to investigate the thermal and electrical effect on ITO thin films.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1312-1314
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• 2007

The effect of gate insulator surface treatment on electrical characteristics of bottom contact (BC) and suspended source/drain (SSD) organic thinfilm transistors (OTFTs) was studied. Triisopropylsilylethynyl pentacene was used as an active material and was printed by ink-jet printing method. In case of the BC OTFTs, threshold voltage was shifted from positive to near zero, and the fieldeffect mobility was increased when the gate insulator surface was treated with hexamethyldisilazane. However, in case of SSD OTFT, threshold voltage shift was not observed and the field-effect mobility was decreased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.60-63
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• 2000

In this study, efficient force reflection algorithm is developed for the Haptic Display by using a proxy concept and friction model. When there are not any contacted obstacles the proxy is following human operator's command trajectory in the 3D virtual space. But when the operator's command trajectory is locating inside of the object, the proxy is constrained by the surface of the object. Here only with the information of the proxy position and operator's command trajectory at every time step, we can calculate the reflection force and its orientation. To display the friction force between two virtual stiff material which are sliding against each other, modified Karnopp's friction model is used. In the friction model, a damping term and a Stribeck effect term are included to display the relative velocity effect and stick-slip effect at the very low relative velocity region respectively.

• Journal of Information Display
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• v.7 no.4
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• pp.1-4
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• 2006

The optical performances of rounded prism films were investigated using a ray tracing technique. The angular distribution of the luminous intensity was obtained as functions of the prism pitch and the curvature of rounded apex and valley of prism arrays. The gain of the on-axis luminance decreased with decreasing curvature (increasing diameter) and pitch. The existence of the curved area on the prism film decreased the recycling efficiency of the prism film, i.e., the rays which would otherwise have been recycled through total internal reflections via the prism surfaces were refracted on the curved regions and redirected toward directions other than the on-axis direction. Quantitative correlation between the luminance gain and the curvature in addition to the prism pitch was obtained, which might serve as basic data for the optimization of prism films and the manufacturing processes.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1080-1082
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• 2008

An ultra-thin reflective flexible LCD film has been demonstrated. The 30% thickness of the display can be reduced by applying a quarter-wave-plate film as upper substrate. A low temperature alignment material and special designed photo spacer were applied in this new display. The bending behavior was improved by reduced thickness.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1135-1138
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• 2006

By ink-jet printing method, organic thin-film transistors (OTFTs) having soluble 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) as an active material were fabricated. The TIPS pentacene solution was made with chlorobenzene and anisole. The solutions were printed on poly (4-vinylphenol) (PVP) dielectric layers and source/drain electrodes by piezo-type heads for bottom contact OTFTs. The dielectric layers had untreated or HMDS-treated conditions. The chlorobenzene device showed the highest field effect mobility of $0.016\;cm^2/Vs$ and the anisole HMDS-treated device shows the highest $I_{on}/I_{off}$ ratio of $10^5$.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.955-958
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• 2003

We report the photo-(PL) and electroluminescence (EL) properties of new conjugated compounds based on diphenyl benzeneamine moiety, 4,4'-(1,4-phenylenedi-(1E)-2,1-ethenediyl]bis(N,N-diphenyl-benzenamine](PEDB) and 4,4'-([1,1 -biphenyl]-4,4'-diyldi-2,1-ethenediyl)bis[N,N-diphenyl-benzenamine)(BPEDB), as emitting materials and dopant materials. The ITO/m-MTDATA/NPB/DPVBi + BPEDB(1%) /Alq3/LiF/Al device shows blue EL spectrum at 458nm and high efficiency(5.3 cd/A). PEDB as dopant shows also blue EL spectrum around ${\lambda}$ max=463nm and 4.1 cd/A high efficiency in ITO/m-MTDATA/NPB/DPVBi + PEDB(1%)/Alq3/LiF/Al device.