• Journal of Korea Society of Industrial Information Systems
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• v.11 no.2
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• pp.79-85
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• 2006

As the portable information appliance is developed, the demand of flat panel display equipments and parts are steeply increased. Most of all, the applications of LCD such as LCD TV, monitor, digital camera, CNS(car navigation system) and game machine become diversified. With the result that the number of BLU production enterprise is increased and the research on the design of backlight with the superior optical properties is persistently in progress. In this study we developed the pattern design tools for CCFL(cold cathode flourescent lamp) backlight to improve the conventional pattern design environment in which the pattern is designed manually from the experience and the trial and error. For the verification of our research, we designed the light reflection surface patterns for a real model of backlight and we measured the brightness uniformity using the BM-7. From the brightness uniformity measurement, the BLU designed using the presented tool showed the tolerable performance only in the first try of pattern design rather than the fifth try of pattern design in case of the conventional pattern design.

• Korea-Australia Rheology Journal
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• v.15 no.4
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• pp.167-171
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• 2003

The backlight unit (BLU) is used as a light source of TFT liquid-crystalline-display (TFT-LCD) module. In this backlight unit, one of important components is the light guide, which is usually made of transparent polymers. Currently, the screen-printing method is mainly used for the light guide as a manufacturing process. However, it has limitation to the flexibility of three-dimensional optical design. In the present paper a new alternative manufacturing method for the light guide with low-cost is proposed. This manufacturing method is named as direct surface forming (DSF), which is very similar to the well-known hot embossing except for partial contact between mold and substrate. The results of this new manufacturing method are presented in terms of processing condition, dimensional accuracy, productivity, etc.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1058-1062
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• 2009

For the investigation of the mechanism of photoelectric characteristics of a hydrogenated amorphous silicon thin film transistor(a-Si:H TFT), spectral characteristics of various backlights were analyzed in terms of the photon energy at each wavelength. Photon energy spectral characteristics were obtained through the multiplication of each photon energy and spectral intensities of backlights at each wavelength and the total photon energies were obtained by the integration of the photon energy spectrums. From the comparison of the experimental photo leakage current and the calculated photon energy, it was possible to conclude that the absorption of illuminated backlight to a-Si:H layer and the generation of electrons and holes are mainly carried out at the wavelength less than 500 nm as described in previous reports.

• Transactions on Electrical and Electronic Materials
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• v.14 no.1
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• pp.16-19
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• 2013

Frequency filters with various filtering wavelengths were used in the photoelectric characterization of hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) and the experimental results were described and analyzed in terms of the photon energy spectral characteristics calculated from the integration of the photon energy and the spectral intensity of transmitted backlight through the filters at each wavelength. From the comparison of the photocurrents and the calculated photon energy spectrums for the filtered ranges of wavelength, it was possible to conclude that the photocurrents are closely related to the photon energy spectrums of the backlight.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.205-207
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• 2009

LCD (liquid crystal display) industry is needed to goods of high reliability and is interested in products without harmful material. In this experiment, we made the LED backlight unit for Automotive-navigation. And for making this backlight unit we used to eight side emitting type white LEDs with 1W high power of the lumileds company. We could know that this backlight unit releases to 6500 nit in 14W power consumption and start up voltage time is under the15ms in the ambient temperature -20 $^{\circ}C$.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.53-55
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• 2007

This paper describes an implementation of a wide-range dimming controller of a LED backlight for Avionics applications such as the control data unit(CDU) and multi-function display(MFD). A feedback controller using a light sensor is proposed to control the brightness in the low dimming range. The proposed controller provides an improved control performance in the wide dimming range of 1:3000 even under the temperature variations. The experimental results are provided to show the effectiveness of the proposed control system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1275-1281
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• 2007

The discharge phenomena in a flat fluorescent lamp for the backlight unit of liquid crystal displays are simulated by sung a two-dimensional fluid model. The numerical methods for the calculation of plasma dynamics and the radiation transport are introduced for the discharge simulation and for the transmission of the vacuum ultraviolet lights. The simulation results are presented to compare the luminance and the luminance efficacy with the variation of gas pressure, gas mixture ratio, driving voltage, and frequency.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.335-337
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• 2008

In this paper, an X-Y channel dimming light emitting diode (LED) backlight with temperature compensation for in LCD TVs is proposed. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio even with much less number of LED drivers than that of the conventional two-dimensional local dimming method. Moreover, the image distortion caused by temperature variation of LED block can be effectively compensated. The validity of the proposed dimming method is verified by simulation and experimental results based on a RGB-LED backlight of a 32-inch LCD TV.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.271-273
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• 2008

A novel white-LED (light emitting diode) backlight system for 46"LCD TVs which involves the average current controlled X-Y channel driving method is proposed, which is composed of 1 converter and row and column channel switches. In the conventional X-Y channel driving driven with a constant voltage source, the driving current of LED increases because the threshold voltage of LED decreases when LED temperature goes up. To maintain the luminance of backlight constant, the average current controlled X-Y channel driving will be employed. Finally the results are confirmed by experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1569-1572
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• 2007

A two-dimensional fluid simulation code has been developed in order to investigate discharge phenomena and to improve plasma luminous efficiency in a Hg flat fluorescent lamp (FFL) for an LCD backlight unit. In this study, the method of a two-dimensional fluid simulation for FFL is explained and the simulation results of Hg-Ar-Ne mixture gas are presented for the enhancement of the luminance efficiency. The effects of various parameters, such as driving voltage, frequency, and gas mixture ratio, are investigated. The luminance efficiency increased with increasing fraction of mercury but the increasing fraction of argon did not affect the efficiency much.