• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.10-15
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• 1999

Using micro-wells on the Mo substrate, we could obtain various tubular-volcano-types of free-standing diamond field emitters by depositing a diamond film detaching the film and turning the film upside down. The field emission characteristics of these structures were investigated as a function of size, shape and the number density of the tubular-volcano-type diamond field emitters. The field emission characteristics, especially the current density, were greatly enhanced with increasing the number density of the tubular-volcano-type diamond field emitters on the Mo substrate. Based on these results, we suggest that the reduction of the well size can give better field emission characteristics by the increase in the number density of the tubular-volcano-type diamond field emitters. Finally, we suggest the feasibility of fabricating a large-area field emission display using our patterned tubular-volcano-type free-standing diamond field emitters.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.133-138
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• 2019

The a-InGaZnO (a-IGZO) thin film transistor (TFT) has the advantages of larger mobility than that of amorphous silicon TFTs, acceptable reliability and uniformity over a large area, and low process cost. A capacitive-type touch sensor was studied with an a-IGZO TFT that can be used on the front side of a display due to its transparency. A capacitive sensor detects changes of capacitance between the surface of the finger and the sensor electrode. The capacitance varies according to the distance between the sensor plate and the touching or non-touching of the sensing electrode. A capacitive touch sensor using only one a-IGZO TFT was developed with the reduction of two bus lines, which made it easy to reduce the pixel pitch. The proposed sensor circuit maintained the amplification performance, which was investigated for various drive conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.59-62
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• 1996

Plasma displays (PDP) as a large area wall-hanging display device are rabidly developed with flat CRT, TPT LCD and etc. Especially, AC Plasma Display Panels(AC PDPs) have the inherent memory function which is effective for large area displays. The memory function in AC PDPs is caused by the accumulation of the electrical charge on the protecting layer formed on the dielectric layer. This MgO protective layer prevents the dielectric layer from sputtering by ion in discharge plasma and also has the additional important roll in lowering the firing voltage due to the large secondary electron emission coefficient). Until now, the MgO Protective layer is mainly formed by E-Beam evaporation. With increasing the panel size, this process is difficult to attain cost reduction, and are not suitable for large quantity of production. To the contrary, the methode of shuttering are easy to apply on mass production and to enlarge the size of the panel and shows the superior adhesion and uniformity of thin film. In this study, we have prepared MgO protective layer on AC PDP Cell by reactive magnetron sputtering and studied the effect of MgO layer on the surface discharge characteristics of ac PDP.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.892-896
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• 2005

In this paper, key issues of stainless steel foil substrates for display applications have been described. We studied and analyzed technical issues on substrate passivation/planarization to control surface roughness and capacitive coupling from conductive substrates. A thick (either multiple or single) passivation/planarization layer needs to be applied on the nonelectronic-grade stainless steel substrate to provide a smooth surface and electrical insulation from the conductive substrate. Especially for large size, high-resolution display applications, low k and thick passivation/planarization layers should be used for appropriate capacitive coupling. Based on our initial study, a unit area capacitance of less than $2nF/cm^2$ of passivation/planarization layers is needed for 32" HD TV OLED displays.

• Journal of the Semiconductor & Display Technology
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• v.5 no.1 s.14
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• pp.1-4
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• 2006

Recently, Ball Grid Arrays(BGAs) are getting used more frequently for a package type. The connectors on a BGA consist of a large number of small solder balls in a grid shape on its bottom side. However, since balls of BGAs mounted on PCBs are not visible, inspection before mounting them is indispensable. High speed non-contact 3D measurement technologies are necessary far real-time measurement of ball height, the most important inspection item. In this paper, an accurate 3D data acquisition system for BGAs is proposed that can acquire 3D profile at high speed using a 3D smart camera and laser slit ray projection. Some clipping and morphological filtering operations are employed to remove spiky error data, which occur due to reflections from some ball area to camera direction.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.151-154
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• 2007

We demonstrate a novel selective patterning process of a semiconducting polymer for channel regions to fabricate an array of organic thin-film transistors (OTFTs). This process is applicable for various organic films over large area. A reflective liquid crystal display based on the OTFT array was produced using the selective patterning through a wettability control.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1374-1382
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• 1995

In TFT-LCDs, as the display size area becomes larger, and the resolution higher, we have to consider the image degradation effects due to the incorporation of the TFT-LCD parameters such as the data-line resistance, the common electrode resistance, the data-line to common parasitic capacitance, and the output characteristics of driver ICs. One of the degradation effects is crosstalk resulting from the coupling between the source bus-line and common electrode. Since a source signal which represents a large number of display data is supposed to vary frequently, the common signal level is affected through the coupling effect, resulting in the degradation of nearby pixel drive signals. Therefore, we proposed a method to compensate for this source-common electrode coupling effect, we also designed and experimented the feasibility of our crosstalk compensation circuit in the actual TFT-LCD. We saw that the newly designed compensation circuit greatly reduced the crosstalk in display pattern image.

• Journal of Information Display
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• v.12 no.2
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• pp.89-92
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• 2011

Advanced static DC magnetron sputtering methods based on the magnet wobbling technique were investigated to achieve highly uniform and homogeneous metallization layers. The novel split sputter mode (SSM) method, wherein the deposition process is divided into two distinct steps, enables the AKT rotary cathode technology to provide excellent layer properties, while keeping a high production throughput. The effectiveness of theSSMtechnique was demonstrated through copper-coated large-area substrates.

• Electrical & Electronic Materials
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• v.12 no.7
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• pp.7-11
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• 1999

Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.334-338
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• 2009

Recently, with increasing demand for flat-panel display product, methods for large area patterning are required. TIR (total internal reflection) holographic photo-lithography isstudied as one of the methods of large area lithography. In conventional TIR holography, light sources for hologram recording and image reconstruction are coherent beams such as laser beams. If the image is reconstructed with an incoherent light source such a UV lamp, the image noise from the coherence of light will be reduced and the UV lamp will be a better light source for large area exposure. We analyzed the effect of spectral bandwidth and angular bandwidth of the light source in image reconstruction and verified image blurring with experiments. For large area patterning which has micro-scale line width, it is expected that TIR holographic photo lithography by UV lamp will become a low-noise and low-priced technique.