• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.683-686
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• 2006

Accompanied by the demand of thin type TV, the application of the TFT LCD display device is more and more extensive. The key material which influences the optical performance of the TFT LCD is optical film. Due to the rapid development of the big size TFT LCD for the recent years, the supply has been unable to meet the demand for its relative material. Therefore, we bring up a alternate choice-the hybrid compensation film which could not only show well optical performance, but also lessen the quantity of usage in TAC in order to make the optical film free of shortage.

• Polymer(Korea)
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• v.35 no.4
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• pp.337-341
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• 2011

To expand the viewing angle of vertical alignment liquid crystal display (VA-LCD), a wide-band compensation film has been newly developed. VA-LCD needs a retardation film with improved oblique viewing property. The retardation film for VA-LCD has been fabricated by solvent casting and subsequent drawing triacetylcellulose (TAC) containing optical additives. Here, optical birefringence and wavelength dispersion of the retardation film strongly depend on the chemical structures of optical additives. Utilizing quantum mechanical computation, the polarizing anisotropy of retardation film was calculated with respect to additives. It is also realized that the wavelength dispersion of polarizing anisotropy depends on the type and location of substituent to the selected main isomer. When two propionates are substituted to the meta position of the selected main isomer, the wavelength dispersion of polarizing anisotropy shows the most gentle slop, which is well matched with the experimental results. The most gentle slop of wavelength dispersion means that the viewing angle characteristics of LCD are less influenced according to the wavelength of light source of LCD, and it's possible to make better image quality than the present level.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.95-101
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• 2012

To manufacture of a completely biodegradable and compostable biomass -based blend polymer film, two types of cellulose acetates(DS=2.4 and DS=2.7) were blended with 5 - 50 wt% of low average molecular weight polylactide(PLA) by mixing each polymer solution having same viscosity in 10 wt% methanol/dichloromethane. Their surface morphology, thermal and mechanical properties were studied. The chemical structures of blend films were confirmed by the fourier transform IR spectroscopy with attenuated total reflection(FT-IR ATR) spectrophotometer. Scanning electron microscope(SEM) photos of blend films of both CAs with less than 5 % of PLA showed homogeneous morphology. On the contrary, the other blends with higher than 20 wt% of PLA content showed a large phase separation with spherical domains. The thermal property of blend films was also analyzed with thermogravimetric analysis(TGA) and differential scanning calorimeter(DSC). The tensile strength of CA/PLA blend films was increased up to $820kg_f/cm^2$ for TAC/PLA and $600kg_f/cm^2$ for DAC/PLA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.294-295
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• 2006

Field sequential liquid crystal display (FSLCD) has advantages such as a high transmittance due to no use of color filter and high color reproductivity because of LED backlight for a luminance source. However, to realize FSLCD response time of the LCD must be below 5ms. In this paper, we have chosen electrically controlled birefringence (ECB) mode for this application and studied film compensation to improve the operating voltage and viewing angle and to achieve a fast response time optimizing the condition of the discotic film and TAC film, operating voltage decreases to 5V, and viewing angle range is $160^{\circ}$ at horizontal and vertical direction, respectively and $120^{\circ}$ in diagonal direction. (contrast ratio > 10:1) and optimized cell exhibits a fast response time of 4ms in most grey levels.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.111-117
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• 2014

With the development of technology, the display industry has been focusing on the development of new types of displays, such as bendable and wearable displays. However, the PVA/TAC polarizing film used in the manufacturing of a normal display is associated with low luminance and low efficiency. If the existing polarization film is replaced with a wire grid polarizer, it is possible to reduce the thickness significantly. Moreover enhanced brightness can also be expected. This study confirms the optical properties of the WGP through a simulation.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.453-456
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• 2005

Color characteristics of a dark state in the IPS-mode depending on viewing direction have been studied. IPS-mode is having a little variation of $d{\Delta}n$ with viewing angle since the LC rotates in plane. However, this mode shows asymmetric light leakage and color characteristics with viewing angle in a dark state. This drawback can be overcome by optimized retardation value of TAC film, pre-tilt angle & $d{\Delta}n$ of LC.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.897-909
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• 2015

This study was conducted to evaluate the effect of weed control on disease incidence, plant growth and fruit quality, and to provide effective method to farmers at the vineyard. At the raincoat greenhouse cultivating 'Campbell Early', several weed controlling methods were compared to the control. Mean temperature of plots between soil covering (C.B., W.F., S.N., P.F. and R.H.) and non soil covering (M.W.2, M.W.3 and U.T.) were similar with $26.2^{\circ}C$ (July) and $25.8^{\circ}C$ (Aug.), but humidity of soil covering was sharply decreased in late-July under 40%. Soil water were all higher in soil covering plots than that of non-soil covering, however, soil temperature was recorded lower in soil covering plots. Disease incidence of Peudocercospora vitis according to soil coverings had effect on black plastic film mulching by decreasing grapevine leaf spot to 85% in July, 69% in August, compared to the control, with showing the smallest lesion incidence in FMB. Among growth characters, internode length and internode width of black plastic film mulching was higher than that of the control. SPAD value of black plastic film mulching was recorded the highest. It was not significant among the treatments, but brix was recorded highly in black plastic film mulching with $14{\sim}15^{\circ}Brix$.