• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.909-915
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• 2009

This work is to develop a vision system for high precision alignment between upper and lower plates required at the imprinting process of the large LCD flat panel. We compose a gantry-stage that has highly repeated accuracy for high precision alignment and achieves analysis about thermal transformations of stage itself. Position error in the stage is corrected by feedback control from the analysis. This system can confirm alignment mark of upper and lower plates by using two cameras at a time for the alignment of two plates. Pattern matching that uses geometric feature is proposed to consider the recognition problem for alignment mark of two plates. It is algorithm to correct central point and angle for the alignment from the recognized mark of upper and lower plates based on the special characteristics. At the alignment process, revision for error position is performed through Look and Move techniques.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1062-1065
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• 2004

The importance of display is becoming increasingly important due to the development of information and industry where it leads to diverse and abundant information in today's society. The demand and application range for FPD(Flat Panel Display), specifically represented by LCD(Liquid Crystal Display) and PDP(Plasma Display Panel), have been rapidly growing for its outstanding performance and convenience amongst many other forms of display. The current focus has been on OLED(Organic Light Emitting Diode) in the mobile form, which has just entered into mass production amid the different types of FPD. Many studies are being conducted in regards to device, vacuum evaporation, encapsulation, and drive circuits with the development of device as a matter of the utmost concern. This study develops a new type of light-emitting materials by synthesizing medical polymer organic chitosan and phosphor material CuS. Chitosan itself satisfies the Pool-Frenkel Effect, an I-V specific curve, with a thin film under $20{mu}m$, and demonstrates production possibility for a living body sensors solely with the thin film. Furthermore, it enables production possibility for EML of organic EL device(Emitting Layer) with liquid Green light emitting and Blue light emitting as a result of synthesis with phosphor material.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1233-1240
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• 2010

In the flat panel display and semiconductor industries, the visual alignment system is considered as a core technology which determines the productivity of a manufacturing line. It consists of the vision system to extract the centroids of alignment marks and the stage control system to compensate the alignment error. In this paper, we develop a Kalman filter algorithm to estimate the alignment mark postures and propose a coarse-fine alignment control method which utilizes both original fine images and reduced coarse ones in the visual feedback. The error compensation trajectory for the distributed joint servos of the alignment stage is generated in terms of the inverse kinematic solution for the misalignment in task space. In constructing the estimation algorithm, the equation of motion for the alignment marks is given by using the forward kinematics of alignment stage. Secondly, the measurements for the alignment mark centroids are obtained from the reduced images by applying the geometric template matching. As a result, the proposed Kalman filter based coarse-fine alignment control method enables a considerable reduction of alignment time.

• Journal of Information Display
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• v.10 no.1
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• pp.33-36
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• 2009

A new hybrid silicon thin-film transistor (TFT) fabrication process using the DPSS laser crystallization technique was developed in this study to realize low-temperature poly-Si (LTPS) and a-Si:H TFTs on the same substrate as a backplane of the active-matrix liquid crystal flat-panel display (AMLCD). LTPS TFTs were integrated into the peripheral area of the activematrix LCD panel for the gate driver circuit, and a-Si:H TFTs were used as a switching device of the pixel electrode in the active area. The technology was developed based on the current a-Si:H TFT fabrication process in the bottom-gate, back-channel etch-type configuration. The ion-doping and activation processes, which are required in the conventional LTPS technology, were thus not introduced, and the field effect mobility values of $4\sim5cm^2/V{\cdot}s$ and $0.5cm^2/V{\cdot}s$ for the LTPS and a-Si:H TFTs, respectively, were obtained. The application of this technology was demonstrated on the 14.1" WXGA+(1440$\times$900) AMLCD panel, and a smaller area, lower power consumption, higher reliability, and lower photosensitivity were realized in the gate driver circuit that was fabricated in this process compared with the a-Si:H TFT gate driver integration circuit

• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.171-176
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• 2001

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. Mold for forming barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing process such as screen printing, sand-blasting and photosensitive glass methods. Mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper, Stripes of grooves of which width 48${\mu}{\textrm}{m}$ and 270${\mu}{\textrm}{m}$, depth 124${\mu}{\textrm}{m}$, pitch 274${\mu}{\textrm}{m}$ was acquired by machining hard and brittle materials of WC, Silicon, Alumina with dicing saw blade. Maximum roughness of the bottom and sidewall of the grooves was respectively 120nm, 287nm in grooving WC. Maximum tilt angle caused by difference between upper-most width and lower-most width was 2$^{\circ}$. Maximum Radius of bottom curvatures was 7.75${\mu}{\textrm}{m}$. This results satisfies the specification for barrier ribs of 50 inch XGA PDP if the groove form of mold was fully transferred to the barrier ribs. Barrier ribs were formed with Silicone rubber mold, which is transferred from grooved hard materials. Silicone rubber mold has elasticity accommodating the waveness of lower glass plate of PDP.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.52-58
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• 2007

This paper describes the PLL of TCON(Timing Controller) chip for FPD(Flat Panel Display). The recent TCON requires wide range frequency operation of $8\sim135MHz$ in PLL. In order to be satisfied this requirement the new V-I converter.circuit. The V-I converter of new architecture increased the minimum/maximum current ratio which widens the operation frequency range of VCO's md also guaranteed linearity of VCO's. The proposed PLL circuits in FPD TCON show the measuring performance of loops RMS jitter in the range of $8\sim135MHz$. The designed circuit was fabricated in 1-ploy 3-metal 0.25um TSMC process technology and has a operation range or $8\sim135MHz$ with 2.5V power.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.59-64
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• 2007

This paper describes the PLL of TCON(Timing Controller) chip for FPD(Flat Panel Display). We propose a new V-I converter which is insensitive to the power supply variation when it is applied to the TCON. The new V-I converter compensated the output frequency of VCO by appling the current that is inversely proportional to the voltage variation. The proposed idea is implemented with a 1-ploy 3-metal 0.25m TSMC CMOS technology and has the output frequency range from 192MHz to 360MHz at the supply voltage of 2.5V. Measurement result shows the RMS jitter of 100ps in the above output frequency range.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.315-321
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• 2005

Chip-on-glass technology to attach IC chip directly on the glass substrate of flat panel display was studied by using induction heating body in AC magnetic field. With applying magnetic field of 230 Oe at 14 kHz, the temperature of an induction heating body made with Cu electrodeposited film of 5 mm${\times}$5 mm size and $600{\mu}m$ thickness reached to $250^{\circ}C$ within 60 seconds. However, the temperature of the glass substrate was maintained below $100^{\circ}C$ at a distance larger than 2 mm from the Cu induction heating body. COG bonding was successfully accomplished with reflow of Sn-3.5Ag solder bumps by applying magnetic field of 230 Oe at 14 kHz for 120 seconds to a Cu induction heating body of 5mm${\times}$5mm size and $600{\mu}m$ thickness.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.612-616
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• 2009

Transparent conductive oxide (TCO) films have been widely used in the field of flat panel display industry. Transparent conductive indium zinc oxide (IZO) thin films with excellent chemical stability have attracted much attention as an alternative material for indium tin oxide (ITO) films. In this study, using a $In_2O_3$ and ZnO powder mixture with a ratio of 90 : 10wt% as a target, IZO films were prepared on polynorbornene (PNB) substrates by electron beam evaporation. The effect of substrate temperature and $O_2$ introduction flow rate were investigated in terms of electrical and optical properties of deposited IZO films. The best electrical and optical properties we obtained from this study were sheet resistance value of $5.446{\times}10^2{\Omega}/{\boxempty}$ and optical transmittance of 87.4% at 550 nm at $O_2$ introduction flow rate of 4 sccm, deposition rate of $2{\AA}$/sec, thickness of 1000 $\AA$ and substrate temperature of $150^{\circ}C$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.55-64
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• 2007

This paper represents characteristics and design example of series loaded LCC type high frequency resonant DC-DC converter with variable parallel capacitor in the secondary side of inductive power transformer. In this converter, ZVS(zero voltage switching) technique is applied to reduce turn-off switching losses, and the applied converter used the PFM switching pattern to control output voltage. The operating characteristics of the proposed converter is analyzed using nomalized parameter such as switching frequency and load factor with varing the secondary parallel resonant capacitor. The results of analysis show the operating characteristics and design method of the proposed converter using characteristic values. And the proposed converter can be applied for the contactless power supply with linear transfer system such as dean room facilities of semiconductor and Flat Panel Display.