• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.314-326
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• 2017

The display, which is closely related to modern life, is being developed as a window on a network connecting individuals, devices, and even other individuals from simple display devices, as the IT industry develops. To achieve a thinner, brighter unit with less consumption for backlighting, the LED light source has applied, and the study of complex light-guiding plates to improve luminance, uniformity, and viewing angle has been initiated. In this paper, we summarize the research results for the scatterers' pattern formation of the light-guiding plate and the arrangement and composition of the light source, which have enabled remarkable development of the LED backlight unit over the last 10 years. In addition, a large-area flat-screen illumination system, applying the light-guiding-plate technology to a currently noteworthy LED light-fixture design, is outlined. Finally, we discuss the direction and way to develop the current technology more progressively.

• Cartoon and Animation Studies
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• s.35
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• pp.89-106
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• 2014

According to Norman McLaren, a Canadian animator, "Animation is not art of moving pictures but art of drawn motions". As he puts it, animation performs the role of magic that turns static to dynamic. Particularly, the space of animation, which is generated through merger of several layers, creates distinctive space that is not to be found in other art genres. Also, the motion of animation, which, unlike live action in film, can be limitlessly created according to a director's subjective domain, has a more autonomous existence. In this paper, I study the space and motion in animation grounded in a director's subjective domain, based on the works by Tabaimo, the Japanese animator director and modern artist. She made an independent use of color sense and perspective that maximized a flat surface, which contributed to creating a new world that doesn't exist in reality. Motion created in such a space is more relative than universal. Therefore, Tabaimo's animation has made aggressive use of a device that gives more originality to the director's themed world, while audience can participate in the strange but new world.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.9-17
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• 2009

Discomfort Glare from the artificial light sources is an important issue in assessment of lighting quality for healthy buildings. Glare, as a factor of the characteristics of brightness, which has been defined as the sensation produced by contrast and luminance within an entire field view, unfavorably influences the occupants who performs visual tasks. It may cause annoyance and discomfort by interruption of visibility. In the whole visual field, glare can be determined by effects of the position, the luminance and the size of the light source and brightness of the surroundings. Therefore, experimental equipment is required to maintain a constant visual lighting environment. Recent studies have been developed and used the instrument for glare sensation evaluation but the instruments showed some difficulties to verify the correlation of glare indicators. The instrument have been developed with reference to former studies. It is called the Glare Tester. This is consist of 2[m]-diameter vertical dome screen painted with white flat paint, and light sources installed inside the screen. These light sources can provide various range of brightness at any inner surface of the screen. 2 Glare light sources can provide the value of luminance within the range of $0{\sim}150,000[cd/m^2]$. Moreover, 12 light sources are used for background luminance and it can perform the value of luminance within the range of $0{\sim}350[cd/m^2]$. Several experiments have been conducted using this Glare Tester to evaluate the range of the visibility, the values of BCD and the glare sensation in lower and upper visual field.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.29-37
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• 2008

With the rapid development of display technology as well as the diversity of display, image quality assessment plays an important role in display color reproduction. The image quality has described by objective evaluation based on the physical measured data, such as contrast ratio, color reproduction range, color temperature, and gamma characteristics, etc., however, the final judgement is achieved by perceptual quality assessment of observers. Therefore, it is necessary to investigate the relationship between physical performance of display and perceptual image quality. Thus, in order to evaluate objectively the color reproduction characteristics of two mobile displays, TFT-LCD and AMOLED, we measured the darkroom contrast ratio of full screen, luminance and color temperature of full-screen white, full-screen gray and color linearity, tone reproduction of color scales for each RGB primary, and color reproduction range. Then the pair-wise comparison is implemented for image experts and naive observers not only to judge their preference on principal evaluation attributes but also to subjectively describe perceived image quality. Through two evaluation processes, we derived the objective bases that can prove the results of subjective image quality assessment by interconnecting physical factors that have influence on observers' preference judgements. Finally, this paper provided important information for improving the image quality and increasing preference from an observer's point of view.

• Journal of Power Electronics
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• v.7 no.4
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• pp.278-285
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• 2007

Recently, plasma display panels (PDP) have become the most promising candidate in the market for large screen size flat panel displays. PDPs have many merits such as a fast display response time and wide viewing angle. However, there are still concerns about high cost because they require complex driving circuits composed of high power switching devices to generate various voltage waveforms for three operational modes of reset, scan, and sustain. Conventional PDP driving circuits use path switches for voltage separation and a scan switch to offer a scan voltage for reset and scan operations, respectively. In addition, there exist reset switches to initialize PDPs by regulating the wall charge conditions with ramp shaped pulses, which means the necessity of specific power devices for the reset operation. Because power for the plasma discharge accompanied by a large current is transferred to a panel via path switches, high power rating switches are used for path switches. Therefore, this paper proposes a novel low-cost PDP driving scheme achieved by not only eliminating path switches but also merging the function of reset switches into other switches used for sustain or scan operations. The simulated voltage waveforms of the proposed topology and experimental results implemented in a 42-inch panel to demonstrate the validity of using a new gate driver that merges the functions of power switches are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.20-23
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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. The mold for forming the barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing processes such as screen printing, sand-blasting and photosensitive glass methods. The mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper, Stripes of grooves of which width 48${\mu}{\textrm}{m}$, depth 124$\mu\textrm{m}$ , pitch 274$\mu\textrm{m}$ was acquired by machining of single crystal silicon with dicing saw blade. Maximum roughness of the bottom of the grooves was 59.6nm Ra in grooving Si. Barrier ribs were formed with silicone rubber mold, which is transferred from grooved Si forming hard mold. Silicone rubber mold has the elasticity, which enable to accommodate the waveness of lower glass plate of PDP. The methods assisted by the microwave and UV was adopted for reducing the forming time of glass paste.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1214-1218
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• 2006

We introduced simple fabrication process for field emission devices based on carbon nanotubes (CNTs) emitters. Instead of using the ITO material as a transparent electrode, a metal (Au) with thickness of 5-20nm was used. Moreover, the ITO patterning process was eliminated by depositing metal layer, before the CNT printing process. In addition, the thin metal layer on photo resist (PR) layer was used as UV block. We fabricated the CNT field emission arrays of triode structure with simple process. And I-V characteristics of field emission arrays were measured. The maximum current density of $254{\mu}A/cm2$ was achieved when the gate and the anode voltage was kept 150V and 3000V, respectively. The distance between anode and cathode was kept constant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.963-966
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• 2000

Plasma display panel (PDP) is a type of flat panel display utilizing the light emission that is produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalk 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 stripes of glass-material wall. In this paper. Stripes of grooves of which width 48 um, depth 124um, pitch 274um was acquired by machining the material of WC with dicing saw blade. Maximum roughness of the bottom and sidewall of the grooves was respectively 120 nm, 287 nm. Maximum tilt angle caused by difference between upper-most width and lower-most width was 2$^{\circ}$. Maximum Radius of curvature of bottom was 7.75 ${\mu}{\textrm}{m}$. This results meets the specification for barrier ribs of 50 inch XGA PDP. Forming the glass paste will be followed by using mold in the near future.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.336.2-336.2
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• 2014

Indium Tin Oxide (ITO) thin films are used as the Transparent Conducting Oxide (TCO), such as flat panel display, transparent electrodes, solar cell, touch screen, and various optical devices. ZnO has attracted attention as alternative materials to ITO film due to its resource availability, low cost, and good transmittance at the visible region. Recently, very thin film deposition is important. In order to minimize the damage caused by bending. However, ZnO thin film such as Ga-doped ZnO(GZO) has poor sheet resistance characteristics. To solve this problem, By adding the conductive metal on films can decrease the sheet resistance and increase the mobility of the films. In this study, We analyzed the electrical and optical characteristics of GZO/Ag/GZO (GAG) films by change in Ag and GZO thickness.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.20.2-20.2
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• 2010

Recently inkjet printing technology has been developed in the areas of low cost fabrication in environmentally friendly manufacturing processes. Although inkjet printing requires the interdisciplinary researches including development of materials, manufacturing processes and printing equipment and peripherals, manufacturing a printhead is still core of inkjet technology. In this study, a piezoelectric driven DOD (drop on demand) inkjet printhead has been fabricated on three layers of the silicon wafer in MEMS Technology because of its chemical resistance to industrial inks, strong mechanical properties and dimensional accuracy to meet the drop volume uniformity in printed electronics and display industries. The flow passage, filter and nozzles are precisely etched on the layers of the silicon wafers and assembled through silicon fusion bonding without additional adhesives. The piezoelectric is screen-printed on the top the pressure chamber and the nozzle plate surface is treated with non-wetting coating for jetting fluids. Printheads with nozzle number of 16 to 256 have been developed to get the drop volume range from 5 pL to 80 pL in various industrial applications. Currently our printheads are successfully utilized to fabricating color-filters and PI alignment layers in LCD Flat Panel Display and legend marking for PCB in Samsung Electronics.