• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4177-4185
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• 2012

LEDs are becoming the most suitable candidate replacing traditional fluorescent lamps because of its eco-friendly characteristics. LEDs are also actively used to design green building system and to make outdoor billboard as a back-light system due to its high energy efficiency. In this paper, we have developed AC direct driver for $12{\times}12$ FLB(flexible LED board) and LED flat light without SMPS. It has LID-PC-R101B driver IC that can support the high power factor and be composed of LED switching circuit in group. Also, an elaborate system designs can guarantee a high luminous efficiency, a high reliability and a low power consumption. The proposed FLB has the ultra slim shape of $450{\times}450$ mm, width of 4 mm and weight of 280 g. In the end, we have developed a prototype of FLB for billboard and flat light for room lighting with AC direct driver iposrder to verify the performance of the proposed system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.1-8
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• 2012

In this paper, we improved the light extraction efficiency by structural change of LEDs on conventional LEDs. We simulated the LEDs light emission as functions of LED side wall angle, various refractive indices the geometrical structures and analyzed the condition improved the light efficiency. We present the results of experimerns and simulations for light output power from LEDs for various refractive indices and the geometrical structures of the LED encapsulants. When the side wall angle range was from 40[$^{\circ}$] to 30[$^{\circ}$], the LED emission increased. LED side wall angle onto LED using the simulation system with a fine tuning of the structure of the LEDs side wall angle is fabricated. Additionally, we changed the side wall angle of LED package with spherical structure and flat structure. The result of spherical structure ray tracting is higher compared with flat structure about 14[%].

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1398-1400
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• 2002

A new PLF-BLU (Plastic Light Fiber-Back Light Unit) using side glowing light fiber rods array for the 42" LCD TV display has been evelopedd. The light fibers were 14mm in diameter and 50cm long pure transparent acrylic rods of 1.49 refractive index. Fine seratees were made on the flat side of rod. extremely bright incandscent light from lamp fed into the fiber si scattered at scratches then emerges through the surface of rod. A typical PLF-BLU system consists of 24 PLFs produced side glow of brightness of 4,500cd/㎡ to 6,500cd/㎡. New PLF-BLU is proved to be a BLU of rigid, bright, no heat generation, and low power consumption, hence a prospective BLU system for very and/or ultra large size TVs. A new LED-PLF-BLU system considered to be a revolutionary to break-through of the BLU technologies has also been developed, and is decribed briefly.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.369-375
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• 2009

In this paper, we propose a 2D-3D convertible display system having a background of full-parallax integral images. The proposed system is composed of integral imaging system and conventional 2D flat display and is able to operate either 3D mode or 2D mode. In 3D mode, the 3D image is generated by combining the 2D main image with the background image based on integral imaging. In 2D mode, the integral imaging system plays a role as the back-light of 2D flat display and then 2D image is observed through 2D flat display. To show the usefulness of the proposed system, we carry out the preliminary experiments and present the successful experimental results.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.316-318
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• 2001

In this paper, the basic characteristics of flat fluorescent lamp using ultraviolet generated from gas discharge and powder type electrolyminescent display(P-ELD) using a phenomenon of the light emission eaused by the electrical field applied to phosphor are studied. The lamp is a simple structure with insulator layer, phosphor layer, and gas gap. Current(displacement current + discharge current) in flat fluorescent lamp using.

• Transactions of the Society of Information Storage Systems
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• v.6 no.1
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• pp.1-5
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• 2010

Holographic data storage system(HDSS) has many noise sources - crosstalk, scattering and inter pixel interference, etc. Generally the intensity of a light generated from the laser source has Gaussian distribution and this ununiformity of light also can make the data page to have a low SNR. A beam apodizer is used to make the laser as a flat-top beam but the intensity distribution is not strictly uniform. The intensity of light can be controlled using image mask. In this paper the intensity distribution of light used for HDSS is controlled by a digital image mask. The digital image mask is changed arbitrarily in real-time with suggested algorithm for the HDSS.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.251-256
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• 2007

The aim of this paper is development of resistivity seismic dilatometer (RSDMT) system. The resistivity module for obtaining apparent resistivity depth plot and seismic module for obtaining shear wave velocity (Vs) depth plot are attached to the conventional flat dilatometer testing equipment. From shear wave velocity profile, the stiffness at low strains of a site can be evaluated in undisturbed condition. And the resistivity value contains some information about water content and mineral characteristics of clayey soil. Specially manufactured resistivity and seismic modules were connected between commercialized DMT blade and drilling rod. To enhance reliability and repeatability of RSDMT test, automatic testing system including notebook based data acquisition system and automatic surface source system were developed. RSDMT system can be performed rapidly and can obtaine more reliable data at the same point compared with the separated testing system. The verification studies for the developed RSDMT system are going to be performed. From these studies, the effectiveness of integrated hybrid testing system will be checked in light of proper evaluation of geotechnical design parameters of clayey soils.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.202-206
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• 2011

We propose a tunable flat-top bandpass filter to pass light in a customized wavelength band by using long-period fiber gratings (LPFG) structure. The LPFG structure is composed of a core mode blocker in between two LPFGs. The bandpass spectrum of the proposed structure is obtained in overlapped wavelength band of two LPFGs operating on the same modes. To analyze the properties, we introduce a mathematical matrix model for the structure. We theoretically demonstrate flexibility of the flat-top bandpass filter with various bandwidths.

• Journal of the Speleological Society of Korea
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• no.64
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• pp.13-26
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• 2004

In this paper, it was studied to investigate and apply the optimal method for well-management of cave with use of solar-cell power source and electro-luminescent tape of illuminating equipment of flat light - lamp for build up the pro-environmental management system of the long way cave on the mountain or the others.

• 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.