• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.57-64
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• 2007

New Chip-on-glass technology to attach an Si chip directly on the glass substrate of LCD panel was studied with local heating method of the Si chip by using thin film heater fabricated on the Si chip. Square-shaped Cu thin film heater with the width of $150\;{\mu}m$, thickness of $0.8\;{\mu}m$, and total length of 12.15 mm was sputter-deposited on the $5\;mm{\times}5\;mm$ Si chip. With applying current of 0.9A for 60 sec to the Cu thin film heater, COG bonding of a Si chip to a glass substrate was successfully accomplished with reflowing the Sn-3.5Ag solder bumps on the Si chip.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.659-665
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• 2008

We demonstrate experimentally that the method of Two-pupil optical scanning technique with PAL-spatial light modulator is capable of performing real-time joint transform correlation(JTC) optical system. Optical addressing is achieved by the use of a photosensitive layer of $\alpha$ - Si which controls the electric field across the liquid crystal The demonstrated technique is based on two-pupil optical heterodyne scanning. The method is independent of a spatial light modulator (SLM) in the Fourier plane. We develop the theory of the technique and evaluate a performance of the method by experimentally estimating the correlation between the target image and the reference image.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.158-163
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• 2002

최근 전자통신기기의 급속화된 발전과 함께 전자부품에 대한 초소형화, 고성능화가 요구되고 있다. 특히 노트북 컴퓨터나, PDA, LCD 모니터와 같이 박막 액정 표시장치(Thin Film Transistor Liquid Crystal Display, TFT-LCD)가 대표적인 예라 볼 수 있다. 이러한 박막 액정 표시장치는 그 내부에 냉음극 형광램프(Cold Cathode Fluroscent Lamp)가 있어서 백라이트의 역할을 하는데 냉음극 형광램프의 특성상 초기 고압의 구동전압을 인가시킬 수 있는 인버터가 필수적이라 하겠다. 본 논문에서는 18인치(4_CCFL), 20인치(6_CCFL) TFT-LCD 모니터용, 멀티램프 구동 인버터를 설계 제작하여 90%에 가까운 효율을 얻었다. 코일손실 및 전자유도의 장애가 없고 불연성의 장점을 가지고, 소형화가 가능한 적층형 압전 변압기를 제작하고 이 제작된 적층형 압전 변압기의 전기적 특성분석을 통한 방전램프 구동용 인버터의 승압용 변압기로써 적용이 가능함을 확인하였다.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.194-196
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• 2002

액정표시장치(LCD; Liquid Crystal Display)는 표현된 정보를 가시화하기 위해 램프의 백라이트가 필수적인데 대부분 부피가 작고 효율과 휘도특성이 좋은 냉음극 방전램프가 사용된다. 램프는 고압으로 구동되며 높은 전압을 얻기 위해 일반적으로 권선 변압기를 사용한다. 그러나 권선 변압기의 경우 자체의 철심이나 권선의 손실로 인하여 출력 효율의 한계가 있으며, 고압을 위해 감긴 코일은 부피를 크게 하며 무겁게 만든다 이를 해결하기 위해 변압기 자체 손실을 줄이고 소형화가 가능하며 높은 승압비을 가진 PAN-PZT계의 적층형 압전 변압기를 제작하였다. 또한 회로의 손실을 줄이기 위한 영전압 스위칭(ZVS; Zero Voltage Switching)과 그리고 LCD패널과 인버터의 불필요한 간섭현상(EMI; Electro-Magnetic Interference)을 줄일 수 있으며 소형화가 가능한 하프 브리지형 압전 인버터를 설계하였다.

• Transactions of Materials Processing
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• v.16 no.8
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• pp.596-602
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• 2007

LGP (Light Guiding Plate) of LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of the major components that affect the product quality of LCD. The optical patterns of LGP(2.2") molds are fabricated by three different methods, namely, (1) laser ablation, (2) chemical etching and (3) LiGA-reflow, respectively. The characteristics of surface patterns and roughnesses of molds and injection molded parts were compared to evaluate the optical characteristics. The optical patterns of injection molded LGP with mold fabricated by LiGA - reflow method showed the best geometric structure. The surface roughness (Ra) of LGP#s with molds fabricated by (1) laser ablation: $Ra={\sim}31nm$, (2) chemical etching: $Ra={\sim}22nm$, and (3) LiGA-reflow: $Ra={\sim}4nm$.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.657-661
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• 2008

Recently, products of electronic industry and related parts are required to have the thickness thinner and thinner to reduce the part weight. To go with this trend, LGP(light guide plate) of LCD-BLU(Liquid Crystal Display-Back Light Unit: It is one of kernel parts of LCD) for cell phone has the thickness of ${\sim}0.3mm$ and the battery case of cell phone has ${\sim}0.25mm$. Accordingly, high speed injection molding is required to mold products which have thinner parts. To achieve high speed injection and proper control of hydraulic unit, various design was applied to conventional injection unit. In the present paper, we concentrated on the molding stability of hydro-mechanical high speed injection machine to make an LGP of 0.3mm thickness.

• Journal of Sensor Science and Technology
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• v.26 no.4
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• pp.274-279
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• 2017

LCD(Liquid Crystal Display) panel cutting problem is a sort of two dimensional cutting stock problem. A cutting stock problem is problem that it minimizes the loss of the stock when a stock is cut into various parts. In the most research of the two dimensional cutting stock problem, it is supposed that the relative angle of a stock and parts is not important. Usually the angle is regarded as horizontal or perpendicular. In the manufacturing of polarizing film of LCD, the relative angle should be maintained at some specific angle because of the physical and/or chemical characteristics of raw material. We propose a mathematical model for solving this problem, a two-dimensional non-Guillotine cutting stock problem that is restricted by an arranged angle. Some example problems are solved by the C++ program using ILOG CPLEX classes. We could get the verification and validation of the suggested model based on the solutions.

• Macromolecular Research
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• v.14 no.1
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• pp.1-33
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• 2006

Polyimides (PIs) exhibit excellent thermal stability, mechanical, dielectric, and chemical resistance properties due to their heterocyclic imide rings and aromatic rings on the backbone. Due to these advantageous properties, PIs have found diverse applications in industry. Most PIs are insoluble because of the nature of the high chemical resistance. Thus, they are generally used as a soluble precursor polymer, which forms complexes with solvent molecules, and then finally converts to the corresponding polyimides via imidization reaction. This complexation with solvent has caused severe difficulty in the characterization of the precursor polymers. However, significant progress has recently been made on the detailed characterization of PI precursors and their imidization reaction. On the other hand, much research effort has been exerted to reduce the dielectric constant of PIs, as demanded in the microelectronics industry, through chemical modifications, as well as to develop high performance, light-emitting PIs and liquid crystal (LC) alignment layer PIs with both rubbing and rubbing-free processibility, which are desired in the flat-panel display industry. This article reviews this recent research progresses in characterizing PIs and their precursors and in developing low dielectric constant, light-emitting, and LC alignment layer PIs.

• Nuclear Engineering and Technology
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• v.5 no.4
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• pp.286-290
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• 1973

Hydroxide free KCI single crystals are prepared and doped with samall amounts of KSH or $K_2$S. The samples are subjected to neutron irradiations while keeping them under the condition of liquid nitrogen temperature in the dark. The irradiated ones are then bleached by using a U.V. lamp and analysed as four different kinds of chemical forms in $^{35}$ S whose valence states are -2, 0, +4 and +6. It semms that the sulphide fraction of $^{35}$ S in doped crystals is higher than that in pure crystals. In addition, two distinct patterns in bleaching process up to 30 minutes results in a fast increase in the sulphide fraction and then the sulphide levels off to a slowly increasing region upon prolonged bleaching. A detailed description on the distribution of $^{35}$ S valence states will be made in connection with point defects in the crystals.

• Journal of Mechanical Science and Technology
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• v.19 no.6
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• pp.1329-1337
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• 2005

The OLED (Organic Light Emitting Diodes) display recently used for the information indicating device has many advantages over the LCD (Liquid Crystal Display), and its demand will be increased highly. The linear cell should be designed carefully considering the uniformity of thin film on the substrate. Its design needs to compute the temperature field analytically because the uniformity for the thin film thickness depends on the temperature distribution of the source (organic material). In the present study, the design of the linear cell will be modified or improved on the basis of the temperature profiles obtained for the simplified linear cell. The temperature distributions are numerically calculated through the STAR-CD program, and the grids are generated by means of the ICEM CFD program. As the results of the simplified linear cell, the temperature deviation was shown in the parabolic form among the both ends and the center of the source. In order to reduce the temperature deviation, the configuration of the rectangular ends of the crucible was modified to the circular type. In consequence, the uniform temperature is maintained in the range of about 90 percent length of the source. It is expected that the present methods and results on the temperature analysis can be very useful to manufacture the vapor deposition device.