• Title/Summary/Keyword: Backlight

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Electricla Properties of Xe Plasma Flat Lamp (Xe 플라즈마 평판 램프의 전기적 특성)

  • Choi, Yong-Sung;Cho, Jae-Cheol;Hong, Kyung-Jin;Lee, Woo-Sun;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.12a
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    • pp.35-38
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    • 2006
  • As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

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A Wide Frequency Range LLC Resonant Controller IC with a Phase-Domain Resonance Deviation Prevention Circuit for LED Backlight Units

  • Park, YoungJun;Kim, Hongjin;Chun, Joo-Young;Lee, JooYoung;Pu, YoungGun;Lee, Kang-Yoon
    • Journal of Power Electronics
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    • v.15 no.4
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    • pp.861-875
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    • 2015
  • This paper presents a wide frequency range LLC resonant controller IC for LED backlight units. In this paper a new phase-domain resonance deviation prevention circuit (RDPC), which covers a wide frequency and input voltage range, is proposed. In addition, a wide range gate clock generator and an automatic dead time generator are proposed. The chip is fabricated using 0.35 μm BCD technology. The die size is 2 x 2 mm2. The frequency of the clock generator ranges from 38 kHz to 400 kHz, and the dead time ranges from 300 ns to 2 μs. The current consumption of the LLC resonant controller IC is 4 mA for a 100 kHz operation frequency using a supply voltage of 15 V.

Comparis on of Optical Characteristics between CCFL and EEFL in Direct-Type Backlight Unit (직하형 백라이트에서의 CCFL과 EEFL의 광학특성 비교)

  • Kim, Byoung-Yong;Kim, Jong-Yeon;Kim, Young-Hwan;Lee, Sang-Keuk;Kim, Jong-Hwan;Han, Jeong-Min;Ok, Chul-Ho;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.428-428
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    • 2007
  • In this study, It was studied about the luminance characteristics of 17inch direct-type back light using EEFL(External Electrode Fluorescent Lamp). EEFI has a long life time because the electrode is installed outside of lamp. And it is produced low price than conventional CCFL. It does not need process of installing internal electrode. But EEFL technology has several problems such as difficulty of design driving inverter, and prevents leckage current along the skin of lamps. Therefore, by the optimizing of inverter properties, 7525 nit center luminance was acquired in almost same power consumption condition. It was almost same luminance in CCFL backlight unit. And it was operated stably in low operating temperature such as the value of $40^{\circ}C$, so that it was adopted in conventional LCD-TV application.

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Optimized Optical Design of LCD Color-matching BLU Using an RGB Light Source (RGB 광원을 사용한 고효율 LCD Color-matching BLU의 광학적 설계)

  • Jeon, Hwa Jun;Gwag, Jin Seok;Kwon, Jin Hyuk
    • Korean Journal of Optics and Photonics
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    • v.30 no.3
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    • pp.101-105
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    • 2019
  • An LCD backlight unit (BLU) using RGB light sources is designed and simulated, in order to improve its optical energy efficiency. A color-matching BLU is designed with a lenticular lens array (LLA) with elements that image the linear RGB light sources onto the RGB subpixels of the color filter. Type-A and Type-B simulations are performed, according to the location of the light sources. As a result, the luminance increases to 210% in Type-A and 270% in Type-B respectively. The optimum values for the height and the gap of the LLA for maximum efficiency are found to be $25{\mu}m$ and $3{\mu}m$ respectively.

Optical Simulation Study on the Performances of Collimating Films for LCD Backlight Applications (액정표시장치 백라이트용 집광필름의 광학특성 분석을 위한 시뮬레이션 기법 연구)

  • Park, Ji-Hee;Lee, Jung-Ho;Jeong, Jin-Ha;Nahm, Kie-Bong;Ko, Jae-Hyeon;Kim, Joong-Hyun
    • Korean Journal of Optics and Photonics
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    • v.18 no.6
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    • pp.432-440
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    • 2007
  • Optical simulation methods such as a ray tracing technique have been widely used to predict the optical performances of collimating films for LCD backlight applications. It is necessary to optimize simulation conditions which have substantial effect on the simulation result in order to predict accurate performances of collimating films. We have set up a very simple backlight model consisting of a reflection film, a virtual flat light-source, and a prism film, which is a representative collimating film for backlight, in order to analyze the simulation conditions which are strongly correlated with the on-axis luminance gain and the viewing-angle characteristics of prism films. It was found that the dependence of the relative change in the on-axis luminance on the structure and material properties of collimating films can be derived from the above-mentioned simple BLU model and from simulation using it. However, the exact reflection property of the reflection film and the distribution of the incident light onto the optical film were found to be very important for revealing exact viewing-angle characteristics of collimating films.

LCD Backlight

  • Ko, Jae-Hyun
    • Proceedings of the Optical Society of Korea Conference
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    • 2007.02a
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    • pp.4-4
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    • 2007
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