• Title/Summary/Keyword: LCD backlight

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A study on implementation of an object-based dimming algorithm on a PWM driven LED BLU LCD board (PWM 구동 LED BLU LCD 보드상의 객체 기반 dimming 알고리즘 구현 연구)

  • Lee, Byung-Hoon;Kim, Young-Jin
    • Proceedings of the Korea Information Processing Society Conference
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    • 2014.04a
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    • pp.928-931
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    • 2014
  • 사용자와의 인터페이스가 많은 모바일 기기에서 TFT LCD는 현재 가장 많이 사용되는 디스플레이로 백라이트(backlight)로 인한 전력 소모가 많아 배터리 수명이 짧아지는 것이 큰 문제이다. 전력 절감을 위해 사용되는 backlight dimming 기법은 명암비 조정에 따른 이미지 왜곡의 보완 기법과 함께 많은 연구가 진행되고 있다. 본 논문에서는 PWM 구동에 의한 LED backlight 제어가 가능한 TFT LCD 보드 구현을 소개하고 이 보드를 대상으로 framebuffer와 LED 제어용 리눅스 장치 드라이버를 사용한 객체 기반의 저전력 인간 시각 만족의 화질 보상 dimming 알고리즘의 구현 연구 내용을 기술한다.

Liquid Crystal Display with High and Stable Color Gamut by Using Pre-compensated Tri-chromatic LED Backlight

  • Chiu, Tien-Lung;Lee, Jiun-Haw
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1515-1518
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    • 2007
  • We demonstrate a high color gamut liquid crystal display (LCD) system (>100 %) by using a precompensated tri-chromatic LED-backlight module over a temperature range of (25 to $70^{\circ}C$), whose pre-compensated optical characteristic balances the spectral redshift and intensity decrease due to the temperature rising during operation.

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Optical performances of flat-lamp backlights for LCD applications

  • Ko, Jae-Hyeon;Yu, Mi-Yeon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1185-1188
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    • 2008
  • The on-axis luminance gain as well as the viewing-angle characteristics of flat-lamp-based backlights have been analyzed for the first time. The on-axis luminance gain on each optical film in flat-lamp backlight was smaller than that obtained from the conventional tubular-lamp-based backlight. The origin of and possible solution to this problem were suggested.

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Design of 30Watt Inverter for high luminance LCD Backlight Application (LCD용 고휘도 Backlight 구동을 위한 30Watt급 인버터의 설계)

  • 허정욱;김태조;임성규
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.747-750
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    • 1999
  • A 30Watt inverter with 300: 1 dimming capability for high luminance, one cell, surface discharge plasma light source for LCD backlight was designed and tested. It was possible to achieve 300:1 dimming control by using the push-pull type inverter with burst-mode dimming control. The surface discharge plasma light cell with luminance of more than 5, 260 cd/$m^2$ was successfully operated.

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High Power Inverter for LCD Backlight Driving

  • Hur, Jeong-Wook;Kim, Tae-Jo;Lim, Sung-Kyoo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.91-92
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    • 2000
  • A high power inverter with 300:1 dimming capability for high luminance, one cell, Osram Planon type, plasma light source for LCD Backlight was designed and tested. It was possible to achieve 300:1 dimming control

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Intelligent Backlighting System for LCD TV

  • Sanchez, Jorge P.;Lim, Sung-Kyoo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.363-366
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    • 2007
  • A new current control technique called Amplitude Shift Modulation (ASM) for cold cathode fluorescent lamps (CCFL) has been developed. This new technique sets and continuously controls the current of each individual CCFL in an LCD backlight lamp array.

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Application of Optical Simulation in Direct-type Backlight Design (직하형 백라이트 설계의 광학시뮬레이션의 응용)

  • Han, Jeong-Min;Kim, Byoung-Yong;Kang, Dong-Hun;Kim, Young-Hwan;Kim, Jong-Hwan;Lee, Sang-Keuk;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.415-415
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    • 2007
  • In this study. it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as LCD television application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps. the gap of lamp and reflection plate and the number of lamps. It has many variation in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps. 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition. and acquired good result in backlight such as the value of the brightness is 6436 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method.

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A Study of The Novel External Electrode Fluorescent Lamp For High Optical Efficiency

  • Yoon, Ji-Su;Jung, Kyu-Bong;Kim, Hyung-Dong;Kang, Jae-Kyung;Kim, Jae-Bum;Jeong, Byoung-Koan;Ahn, Byung-Chul;Yeo, Sang-Deog
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1412-1414
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    • 2006
  • We study on the Electro Optical Properties of the EEFL (External Electrode Fluorescent Lamp) Backlight system is based on the lamp type characteristics and diameter of the lamp tube under the equal manufacturing of the lamps. In this contribution, through the analysis of the different lamp type and diameter of the lamp tube gain the effective luminance and reduce the lamp voltage from aspect in the electro optical properties with EEFL and LCD backlight system.

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Novel Impulsive Driving Schemes for 120Hz LCD Panels

  • Nam, Hyoung-Sik;Oh, Jae-Ho;Shin, Byung-Hyuk;Oh, Kwan-Young;Berkeley, Brian H.;Kim, Nam-Deog;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.818-821
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    • 2007
  • Two new impulsive driving technologies for use in 120Hz LCD panels are proposed to improve moving picture quality. One technology generates the dark frame using an adder and a shifter simply without using any LUTs. The other is a backlight flashing method designed to avoid ghost images. Using the PBET metric, measured MPRT values were 10.8ms and 4.4ms, respectively.

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