• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.153-157
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• 2009

A Highly efficient Mercury-free Flat Fluorescent Lamp (MFFL) with dielectric barrier Xe gas discharge was developed for an alternative of conventional line-type Cold Cathode Fluorescent Lamps (CCFLs) which shows a wide voltage margin and a stable discharge operation for diffuse glow discharge with an application of a auxiliary electrode. Electro-optic characteristics of the MFFL were examined through the changes in ambient temperature, total pressure and Xe partial pressure. the single cell is expanded into a multi-structured configuration to realize a large sized lamp by a simple repetition of the single cells, and a new driving scheme is proposed for an adaptive brightness control using dual auxiliary electrodes and bi-polar drive scheme. In addition, interesting application of this ultra high luminance flat lamp by the optimization of the gas condition and the pattern of the rear phosphor layer is suggested as a good alternative of daylight lamp source

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.155.2-155.2
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• 2011

We present development of the calibration system for IGRINS (the Immersion GRating Infrared Spectrograph). We mainly use Th-Ar and U hollow cathode lamp as the spectral calibration source and telluric features can be used additionally. For the flat source, we selected a 3000K tungsten halogen lamp with 2 inch integrating sphere. From Light Tools simulation, the result flat image through calibration optics satisfied <1% flatness error requirement. We also present mechanical design of calibration box that will be attached on the IGRINS dewar. Three moving stages are designed to perform switching mechanism between all of the observing modes - target observation, flat, precision RV measurement, and spectro-polarimetric observation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.488-492
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• 2013

Current limiting diode (CLD) was fabricated using junction field effect transistor (JFET) structured two small cells and eight large cells. Two small cells and eight large cells were connected in parallel and the obtained constant current was 110 mA. The application of CLD in each of the parallel circuits on chip on board (COB) type LED lighting source, could significantly reduce the current deviation within the parallel circuits. The applications of CLD on AC power small lighting source, battery power low voltage parallel lighting source and AC flat lighting source were investigated.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1189-1192
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• 2008

A new mercury-free flat fluorescent lamp with a single cell having dimension 2.2inches across the diagonal, had been developed which shows a wide, stable operating voltage margin, high luminance and luminous efficacy by adopting the bipolar pulse drive scheme. In this paper, the single cell is expanded into a multi-structured configuration to realize a 32inch sized panel across the diagonal by a simple repetition of the single cells. A driving scheme is proposed for a 2-bit areal selective dimming using dual auxiliary electrodes and bipolar drive scheme.

• 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.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1489-1491
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• 2004

PD in air is accompanied by light, sound and electromagnetic wave. Light and sound can be prevented from blocking between PD sources and sensor but electromagnetic wave can be transferred to long distance without any interference an captured by antenna. This paper investigated the wideband antenna is appropriate for sensing Partial discharge in air. PD was generated from simulated PD source which consist of needle and flat electrode with small gap. Signals obtained from wideband antenna were diminished in both time and frequence region with the distance between PD source and antenna.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.45-47
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• 2005

The Dielectric Barrier micro-hollow cathode structure and it's upper pD limitation are investigated for determining of optimum hollow cathode discharge condition. In experiment, discharge is sustained by AC diriving and investigated gas is pure Xe. From Experiment, Optimum pD range is lower than 0.72 torr.cm at pure Xe and Cu cathode.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.19-26
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• 2015

This paper presents design, fabrication, and performance evaluation of a high voltage power supply for Carbon Nano Tube-based planar light sources. The proposed power supply employs an LLC resonant half-bridge converter and a sixfold voltage-multiplying rectifier. Steady-state characteristics of the voltage-multiplying rectifier are analyzed and used to derive the input-to-output voltage conversion ratio of the power supply. The input-to-output frequency response characteristics of the LLC tank circuit are analyzed and utilized in designing a proto-type power supply which produces a 15 KV output using a 400 V input source. The high-voltage transformer is fabricated using a sectional bobbin structure with an epoxy impregnation, in order to provide sufficient insulation for high voltage operations. The performance of the proposed power supply is confirmed with stable and reliable operations at the 15 KV output from no load to nominal load conditions. The proposed power supply is well suited as an electric ballast required stable operations of Carbon Nano Tube-based planar light sources.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1165-1168
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• 2005

We review discharge characteristics of fluorescent lamps having noncircular cross sections. The developmental and theoretical history of noncircular cross-section lamps is summarized chronologically. In particular, discharge characteristics of noncircular cross-section lamps will be summarized and analyzed including plasma contraction, electron temperature, and ambipolar diffusion loss, which might give us some insights into the way to develop more efficient and uniform flat fluorescent lamps, which have recently arisen as a new light source of large-size backlight units for LCD TV applications.