• Journal of the Optical Society of Korea
• /
• v.18 no.1
• /
• pp.9-14
• /
• 2014

We numerically investigate the effect of sunlight polarization on the absorption efficiency of V-shaped organic solar cells (VOSCs) using the finite element method (FEM). The spectral distribution of absorbance and the spatial distribution of power dissipation are calculated as a function of the folding angle for s-and p-polarized light. The absorption enhancement caused by the light-trapping effect was more pronounced for s-polarized light at folding angles smaller than $20^{\circ}$, where s-polarized light has a relatively larger reflectance than p-polarized light. On the other hand, the absorption efficiency for p-polarized light is relatively larger for folding angles larger than $20^{\circ}$, where the smaller reflectance at the interface of the VOSC is more important in obtaining high absorption efficiency.

• Journal of Information Display
• /
• v.2 no.3
• /
• pp.72-77
• /
• 2001

Amorphous silicon thin-film transistors (a-Si TFTs) were incorporated into Mo-tip-based triode-type field emitters and diode-type ones of carbon nanotubes for an active-matrix cathode (AMC) plate of field emission displays. Also, we developed a novel surface-treatment process for the Mo-tip fabrication, which gleatly enhanced in the stability of field emission. The field emission currents of AMC plates on glass substrate were well controlled by the gate bias of a-Si TFTs. Active-matrix field emission displays (AMFEDs) with these AMC plates were demonstrated in a vacuum chamber, showing low-voltage matrix addressing, good stability and reliability of field emission, and highly uniform light emissions from the anode plate with phosphors. The optimum design of AMFEDs including a-Si TFTs and a new light shield/focusing grid is discussed.

• Journal of Information Display
• /
• v.7 no.1
• /
• pp.1-6
• /
• 2006

A 10" carbon nanotube field emission display device was fabricated with a novel structure with a hopping electron spacer (HES) by screen printing technique. HES plays a role of preventing the broadening of electron beams emitted from carbon nanotubes without electrical discharge during operation. The structure of the novel tetrode is composed of carbon nanotube emitters on a cathode electrode, a gate electrode, an extracting electrode coated on the top side of a HES, and an anode. HES contains funnel-shaped holes of which the inner surfaces are coated with MgO. Electrons extracted through the gate are collected inside the funnel-shaped holes. They hop along the hole surface to the top extracting electrode. In this study the effects of the addition of HES on emission characteristics of field emission display were investigated. An active ozone treatment for the complete removal of residues of organic binders in the emitter devices was applied to the field emission display panel as a post-treatment.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.15-18
• /
• 2004

Recent progress of the in-plane switching (IPS) TFT-LCD technologies is reviewed. We call the improved new technology 'advanced super IPS TFT-LCD(AS-IPS)'. After suppressing the viewing angle dependency of essential display characteristics, recent brightness, viewing angle and motion picture quality has been highly improved. The stage is now introducing it into consumer information appliance for higher display performances, by which we could open a large size digital LCD TVs application.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1995.10a
• /
• pp.191-196
• /
• 1995

The intelligent human-machine interface (HMI) has been developed to enhance the safety and availability of a nuclear power plant by improving operational reliability The key elements of the HMI are the large display panels which present synopsis of the plant status and the compact, digital work stations for the primary operator control and monitoring functions. The work station consists of four consoles such as a dynamic alarm console (DAC), a system information console (SIC), a computerized operating-procedure console (COC), and a safety related information console (SRIC). The DAC provides clean alarm pictures, in which information overlapping is excluded and alarm impacts are discriminated, for quick situation awareness. The SIC covers a normal operation by offering all necessary plant information and control functions. In addition, it is closely linked with the DAC and the COC to automatically display related system information under the request of these consoles. The COC aids the operator with proper emergency operation guidelines so as to shutdown the plant safely, and it also reduces his physical/mental burden by automating the operating procedures. The SRIC continuously displays safety related information to allow the operator to assess the plant status focusing on plant safety. The proposed HMI has been validated and demonstrated with on-line data obtained from the full-scope simulator for Yonggwang Units 1,2.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.27 no.1
• /
• pp.109-120
• /
• 2004

In large scale complex system such as a nuclear power plant, it is important to select guidelines and/or checklist to evaluate the system performance, especially human performance for visual information while the number of evaluation items of the guidelines and checklist is voluminous. This paper presents the methodology and experiment for the relative weights or priority selection of evaluation items on the advanced information display of main control room in a nuclear power plant. To summarize this, 1) many human factors guidelines of Visual Display Terminal(VDT) displays are collected, 2) the collected guidelines are integrated and unified based on some rules in a way to avoid confusion or errors about work performances of operator groups, 3) using the unified guidelines, the more important items are defined when the advanced information indexes are applied by using the Analytic Hierarchy Process(AHP). For employing the AHP, the decisions and response of many human factors evaluation specialists in this field are collected to get the priority order of the evaluation items of VDT. The result of this paper will be applied for the evaluation of the usability of next generation of nuclear power plant which is focused on the visual information display on VDT.

• International journal of advanced smart convergence
• /
• v.4 no.2
• /
• pp.76-83
• /
• 2015

Various products are displayed and traded in superstores. Therefore, providing the information of these diverse products plays a crucial part in acknowledging their presence. Currently, superstores mostly utilize printed materials to provide product information and promotion of displayed products. A display equipment is utilized for providing product information and promotion of certain high-end and new products. As such, utilizing an expensive display equipment in order to provide product information fragmentarily for 1 product or successively can be referred to as being inefficient. This paper aims at proposing a method that enables the description of product information efficiently by utilizing a display specific for store support in order to overcome the restriction mentioned above. A test was executed in order to verify the potential of the method of providing product information though the proposed display.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3645-3650
• /
• 2012

Two new blue emitting cationic iridium(III) complexes with two substituted 2-phenlypyridine ligands as main ligands and one 2,2'-biimidazole as an ancillary ligand, $[(L1)_2Ir(biim)]Cl$ (1) and $[(L2)_2Ir(biim)]Cl$ (2), where L1 = 2-(2',4'-difluorophenyl)-4-methylpyridine, L2 = 2-(2',4'-difluoro-3'-trifluoromethylphenyl)-4-methylpyridine and biim = 2,2'-biimidazole, were synthesized for applications in phosphorescent organic light-emitting diodes (PhOLEDs). Their photophysical, electrochemical and electroluminescent (EL) device performances were examined. The photoluminescent (PL) spectra revealed blue phosphorescence in the 450 to 485 nm range with a quantum yield of more than 10%. The iridium(III) compounds studied showed good solubility in organic solvents with no solvatochromism dependent on the solvent polarity. The solution-processed OLEDs were prepared with the configuration, ITO/PEDOT:PSS (40 nm)/mCP:Ir(III) (70 nm)/OXD-7 (20 nm)/LiF (1 nm)/Al (100 nm), by spin coating the emitting layer containing the mCP host doped with the iridium phosphors. The best performance of the fabricated OLEDs based on compound 1 showed an external quantum efficiency of 4.5%, luminance efficiency of 8.52 cd $A^{-1}$ and blue emission with the CIE coordinates (x,y) of (0.16, 0.33).

• Macromolecular Research
• /
• v.16 no.4
• /
• pp.337-344
• /
• 2008

The following series of blue EL polymers was synthesized using the Suzuki polymerization method: poly(3',6'-bis(3,7-dimethyloctyloxy)-9,9'-spirobifluorene-2,7-diyl) poly[$(OC_{10})_2$-spirobifluorene], poly{3',6'-bis(3,7-dimethyloctyloxy)-9,9'-2,7-diyl-co-4-(3,7-dimethyloctyloxy) phenyl-diphenylamine-4',4'-diyl} poly[$(OC_{10})_2$-spirobifluorene-TPA] (5:1, 9:1) and poly{3',6'-bis(3,7-dimethyloctyloxy)-9,9'-spirobifluorene-2,7-diyl-co-4-(6-((3-methyloxetan-3-yl)methoxy)hexyloxyphenyl-bisphenylamine-4',4'-diyl) poly[$(OC_{10})_2$-spirobifluorene-TPA-oxetane]. The weight average molecular weight (Mw) and polydispersity of the resulting polymers ranged from $1.6{\times}10^4-1.5{\times}10^5$ and 1.77-2.31, respectively. The resulting polymers were completely soluble in common organic solvents and were easily spin-coated onto an indium tin oxide (ITO) substrate. The polymers exhibited strong blue emission peaking at 450 nm. The maximum brightness and luminance efficiency were $9,960\;cd/m^2$ and 1.2 cd/A, respectively.

• Macromolecular Research
• /
• v.15 no.6
• /
• pp.533-540
• /
• 2007

We designed and successfully synthesized UV curable, functional acrylate monomers having a polarizing group, i.e., an electron-withdrawing and/or electron-donating group for the optical materials of high refractive index. Optical polymer films made from the functional methacrylate monomers were achieved with photo crosslinking under UV illumination. A monomer having amino and cyano groups (Dimer-CN) exhibited the highest refractive index ($n_{TE}$=1.595 at 850nm) among the studied methacrylate derivatives, due to the large polarizability of the dipolar monomer structures with electron-donating and withdrawing groups. By controlling the compositions of the functional acrylate monomer of copolymers, the refractive indices of the polymers were readily adjusted within a wide range of 1.498-1.595. The copolymers showed a high glass transition temperature $(T_g)$ and good thermal stability, which are desirable for optical applications. $T_g$ and $T_{10%}$ (10%-weight loss occurred) of the copolymers ranged from $120-140^{\circ}C$ and from $329-387^{\circ}C$, respectively.