• Title/Summary/Keyword: 플리커현상

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Development of an Electronic Ballast for 70W Ceramic Discharge Metal Halide Lamps with Step Down Converter (강압형 컨버터를 이용한 70W CDM 램프용 전자식 안정기의 개발)

  • 김일권;길경석;김진모
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.435-439
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    • 2002
  • This paper describes a design and fabrication of an electronic ballast for 70[W] ceramic discharge metal halide lamps. The proposed ballast is composed of a rectifier, an active power factor correction circuit (PFC), a half-bridge inverter, a LC resonant circuit and a microprocessor. The developed ballast also includes a specially designed time circuit which provides reignition of lamps. Running frequency of the ballast is set at 40[kHz] to avoid acoustic-resonance and flickering. From the experimental results, input power factor and efficiency of the ballast are estimated 99.8[%] and 93.1[%)] respectively.

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Implementation of Motion Picture Processor for Low-cost CSTN-LCD (저가형 CSTN-LCD 동영상 프로세서 설계)

  • Kim, Yong-Bum;Choi, Myung-Ryul
    • Journal of Korea Multimedia Society
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    • v.9 no.8
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    • pp.963-970
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    • 2006
  • In this paper, we proposed a motion picture processor for using low-cost color super twisted nematic liquid crystal display(CSTN-LCD). The proposed processor apply a new driving scheme using SFP(Subgroup Frame Pattern), so we extends gray scale and eliminates flicker phenomenon. In addition, we apply the BFI (Black Field Insertion) to the design compensated for response time of a LC (Liquid Crystal). We use an edge enhancement and interpolation method to improve image quality of motion picture. The hardware architecture of proposed processor has been implemented and verified on a prototype FPGA board. The proposed method can be used in the display devices such as PDA(Personal Digital Assistants), mobile phone, and PMP(Portable Multimedia Player).

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Dimming Level Control Technique for Lighting / Communication Functions in Visible Light Communication Systems (가시광통신 시스템에서 조명/통신 기능을 위한 효과적인 Dimming level control 기법)

  • Lee, Kyu-Jin
    • Journal of Convergence for Information Technology
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    • v.8 no.5
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    • pp.153-158
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    • 2018
  • In this paper, we have studied a dimming level control method to satisfy both lighting and communication performance in visible light communication system. In the case of the most commonly used OOK and RZ-OOK modulation schemes, continuous Burst Zero Duration will seriously degrade the lighting function. This causes not only the illumination but also the performance of the entire system to deteriorate. Through this study, we analyzed the dimming level characteristics of the existing system and proposed the Illegal Pulse Insertion (IPI) algorithm as a technique to increase the dimming level. Through this, it is possible to effectively control the dimming level and improve the QoS of both lighting and communication by resolving the flicker phenomenon and dimming level reduction in the existing modulation and demodulation system.

A Study on the Condition of LED Lights Flicker (국내 LED 조명등에서 플리커 현상에 관한 연구)

  • Heo, Min;Ko, Jae-jun;Kim, Chung-hyeok
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.11
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    • pp.729-735
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    • 2016
  • It is highly important issue to use an energy efficiently for sustainable prosperity of mankind. From this point of view, using LED lighting can be a good alternative because it has a lot of advantages such as high efficiency, long life time and eco-friendly manufacturing process. That is the reason why using LED lighting has been encouraged worldwide. However, in situations that LED lighting is replacing traditional lighting quickly, the problem of the flicker of LED lighting has emerged as an important issue. Therefore, in foreign countries like US or Japan in order to ensure the reliability of LED lighting, study for flickering effects of the human body and test methods are have been actively conducted. But related research in domestic situation is an insufficient condition. In this study, a flicker characteristic was measured conventional lamps such as incandescent lamps or fluorescent lamp and 81 items of LED lightings which are distributed in domestic markets.

A Study on LED Driver Compatible with Triac-dimmer Employing Active Bleeder (능동 블리더 회로를 적용한 조광기 호환용 LED 구동회로에 관한 연구)

  • Yeom, Bong-Ho;Kim, Teak-Woo;Kim, Ju-Rae;Hong, Sung-Soo
    • Proceedings of the KIPE Conference
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    • 2013.07a
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    • pp.159-160
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    • 2013
  • 본 논문에서는 백열등 조도 조절용 조광기에 호환 가능한 LED 구동회로를 제안한다. 조광기와 일반적인 LED 구동회로를 연결할 경우 트라이악(Triac)의 오동작에 의해 플리커(Flicker) 현상이 발생하는 문제점을 지니고 있다. 트라이악의 오동작을 방지하기 위해서는 트라이악에 일정 크기 이상의 전류가 인가되어야 하며 이를 만족하기 위한 조광기 호환회로가 필수적이다. 이러한 호환회로로써 수동 블리더(Passive Bleeder)는 전 동작 구간에서 전력소모가 발생하는 단점을 지니고 있다. 본 논문의 제안회로는 역률 만족을 위 해 Valley-fill 회로를 적용하였으며 트라이악의 오동작 시점을 정확히 검출하여 새로운 방식의 능동 블리더(Active Bleeder)를 적용함으로써 조광기의 오동작을 방지하면서 수동 블리더에 비해 효율이 개선되는 장점을 지닌다. 또한, Valley-fill과 인덕터를 적용한 1단 구성으로 효율개선 및 역률 개선의 장점과 입력 전류 리플의 감소로 인한 EMI 노이즈 저감 효과를 나타낸다. 본 논문에서는 제안된 회로의 타당성을 검증하기 위하여 13W급 조명용 LED 구동회로의 시작품 제작을 통해 그 우수성을 확인한다.

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A Comparative Study on the Quantitative Analysis of the Flicker Phenomena in the Amorphous-Silicon and Poly-Silicon TFT-LCDs (비정질 및 다결정 실리콘 TFT-LCD에서의 플리커(flicker) 현상 비교 분석 연구)

  • Son, Myung-Sik;Song, Min-Soo;Yoo, Keon-Ho;Jang, Jin
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.1
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    • pp.20-28
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    • 2003
  • In this paper, we present results of the comparative analysis of the flicker phenomena in the poly-Si TFT-LCD and a-Si:H TFT-LCD arrays for the development and manufacturing of wide-area and high-quality TFT-LCD displays. We used four different types of TFTs; a-Si:H TFT, excimer laser annealed (ELA) poly-Si TFT, silicide mediated crystallization (SMC) poly-Si TFT, and counter-doped lateral body terminal (LBT), poly-Si TFT. We defined the electrical quantity of the flicker so that we could compare the flickers quantitatively for four different 40" UXGA TFT-LCDs. We identify three factors contributing to the flicker, such as charging time, kickback voltage and leakage current, and analyze how much each of three factors give rise to the flincker in the different TFT-LCD arrays. In addition, we suggest and show that, in the case of the poly-Si TFT-LCD arrays, the low-level (minimum) gate voltages should be carefully chosen to minimize the flicker because of their larger leakage currents compared with a-Si TFT-LCD arrays.

The Development of a High Efficiency Luminaires Reflector for Tunnel Lighting (터널용 고효율 조명기구 반사판의 개발)

  • Kim, Gi-Hoon;Hwang, Jae-San;Yun, Mee-Rim;Kim, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.15 no.2
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    • pp.1-6
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    • 2001
  • Tunnel lighting in Korea has the problems of unsatisfactory illuminance uniformity which obstructs driver's vision, a flicker phenomenon on wall of tunnel, a heavy glare, low efficiency of luminaires, low utilization factor, and high energy consumption. We developed a high efficiency luminaire reflector for tunnel lighting which removes these problems. Developed luminaire saves energy and improves lighting environment by increasing 10% of luminaire efficiency. It can reduce installation cost by decreasing the number of luminaires, while average illuminance of 200[lx], overall uniformity of 0.4, longitudinal uniformity of 0.7, and electric power consumptions per unit area of 3.7[W/m$^2$] are accomplished.

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360° Projection Image Analysis Method for the Calibration (보정을 위한 고해상도 360° 프로젝션 영상 분석 방법)

  • Han, Jung-Soo;Kim, Gui-Jung
    • Journal of Digital Convergence
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    • v.13 no.12
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    • pp.203-208
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    • 2015
  • Image degradation will occur depending on hardware characteristics according to the lapse of time between beam projectors when multivision system is installed in the Theme park/Exhibition/Science Museum. In this paper, we have researched the 10-bit High-depth and high-resolution $360^{\circ}$ projection image analysis technique to solve the problems of quality and the maintenance of the theater. The goal is to minimize the economic losses and the development of special theater calibration system that can efficiently support a quality of an image. We proposed the method of image analysis technology, and explained the detailed functions and evaluation methods for image analysis technique. Evaluation method included the performance items, and proposed reasonable value to the experimental method and the goal value.

Development of Visible Light Communication (VLC) System Technology Based on High Brightness LED light (고휘도 LED 조명 기술을 이용한 고속 가시광통신 시스템 기술 개발)

  • Lee, Jong-Hyeok;Jang, Kyung-Soon;Kim, Byung-Gyu;Kim, Jin-Ho
    • Convergence Security Journal
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    • v.14 no.7
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    • pp.29-36
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    • 2014
  • In this study, we design and develop a VLC test-bed system which has been recently issued and focused as good convergence technology in the world. We classify the developed system into transmission part including analog LED driver module, digital signal modulation module, and receiver part with light sensing module and signal demodulation module. Then we introduce important characteristics and components. We analyze some factors for each module. To validate the communication of the designed VLC system, we develop a VLC sender-receiver simulator which can control the dimming factor and flicker-free effect. From the developed system, we observed about 12Mbps of data transmission rate with 0.5m~1m of distance, without packet loss. We verified the real-time communication with multimedia streaming which can be considered as very high date rate. The developed system and technology will be useful for some converged data services like indoor positing, home appliances, and indoor parking system.

Prediction of Flicker for PDP Devices (플라즈마 디스플레이 패널의 플리커 발생에 대한 예측)

  • Jin Guang-Xu;Kang Sung-Ho;Hong Ki-Sang
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.2 s.302
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    • pp.9-18
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    • 2005
  • Flicker is the 'variation in brightness or he perceived won stimulation by intermittent or temporally non uniform light'. This phenomenon is blown as the cause of eye strain and headaches. Many researchers are dedicated to reducing this phenomenon. The flicker phenomenon also exists in PDP as some other display types, and is a critical problem in 50 Hz PDP. However, it is difficult to define flicker by more than one subjective judgment. So, an objective measurement of flicker is necessary and convenient for research on displays. In this paper, a computational prediction model is proposed which is used to predict luminance flicker (not chromatic flicker) by giving a quantitative output that describes the probability of occurrence of flicker. Through this work, we expected to provide a practical tool for flicker-free design in PDP.