• Title/Summary/Keyword: LCD Reflective film

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Tension Control for Coating Winding Process of LCD Reflective Film (LCD 반사필름의 접합 와인딩 공정을 위한 장력 제어)

  • Hwang, Jung-Ho;Roh, Ji-Hoon;Park, Ki-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.7 s.196
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    • pp.49-59
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    • 2007
  • The demand for the metal coil coated with reflective film is rapidly increasing with the increasing demand of notebook PCs and LCD monitors. During the coating process, it is very important to regulate tension of the coil metal since fluctuation of the tension can significantly degrade quality of the product. In this study, a tension controller has been developed for winding process of LCD reflective film coating. The controller has been tested on the existing coating facilities, and the results are to be given in this paper.

Design of a Reflective STN LCD On the Poincare Sphere (뽀앙까레 구면을 이용한 반사형 STN LCD의 설계)

  • 김도연;이서헌;심사용;이기동;김재창;윤태훈
    • Proceedings of the Optical Society of Korea Conference
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    • 2001.02a
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    • pp.140-141
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    • 2001
  • 반사형 STN-LCD (supertwisted nematic liquid crystal display) 는 많은 display에서 사용되고 있는 LCD mode 중의 하나이다. 그러나 현재 많이 사용되는 반사형 STN-LCD는 그림 1과 같이 한 장의 polarizer와 두장의 retardation film을 사용하는 구조이므로 각각의 component에 대한 parameter들에 의해 display의 표시 성능이 좌우된다. 먼저 Reflective STN-LCD의 보상에 필요한 parameter를 살펴보면, 그림 1과 같이 5개 ( $\alpha$, ø$_1$, ø$_2$, 각 retarder의 retardation : Δnd$_1$, Δnd$_2$)의 parameter의 결정이 필요하다. (중략)

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Electro-optic Characteristics of the fringe-field Driven-reflective Liquid Crystal Display with One Polarizer (1매의 편광판으로 구성된 반사형 Fringe-field Switching Mode의 전기 광학 특성)

  • 정태봉;박지혁;이종문;김용배;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.2
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    • pp.131-137
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    • 2003
  • We have performed computer simulation to obtain electro-optic chracteristics of reflective liquid crystal display (LCD) using wide viewing angle LC mode, fringe field switching(FFS). Unlike other reflective LCD modes, in the FFS mode, the LC director in plance so an application to reflective display consisted of polarizer, LC layer and reflector is possible. when an incident light is 550mm, the optimal cell retardation value is 0.1365${\mu}$m and the efficiency of reflectivity is high over 90% with very little wavelength dispersion. Further, we have studied a new reflective display with polarizer, optical compensation film with half plate, LC plus reflector. The display with optimized cell parameters shows high contrast ratio (CR) over 130 with high light efficiency over 90% at normal direction and the CR greater than 5 exists over 60$^{\circ}$ of polar angle in all directions.

Design and Fabrication of a Reflective Bistable TN LCD (반사형 쌍안정 TN LC 셀의 설계 및 제작)

  • 백흠일;장기철;이기동;윤태훈;김재창
    • Korean Journal of Optics and Photonics
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    • v.10 no.4
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    • pp.279-282
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    • 1999
  • We designed and fabricated a single polarizer mode bistable twisted nematic liquid crystal display by employing a wide-band λ/4 retardation film to enhance the dark state property. We theoretically and experimentally confirmed the necessity of a wide- band λ/4 retardation film in a single polarizer mode. We obtained brighter image than previous reflective BTN LCDs.

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Experimental and Simulation Study of the Optical Performances of a Wide Grid Polarizer as a Luminance Enhancement Film for LCD Backlight Applications

  • Seo, Jae Seok;Yeom, Tae Eun;Ko, Jae-Hyeon
    • Journal of the Optical Society of Korea
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    • v.16 no.2
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    • pp.151-156
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    • 2012
  • Reflective polarizers can be used as luminance enhancement films for LCD backlights via the polarization recycling process. The optical performances of a wire grid polarizer (WGP) as a reflective polarizer adopted in edge-lit backlights were investigated by luminance evaluation and a time-domain simulation technique. The results were compared to those of a commercial dielectric multilayer film. The luminance gain factor of WGP was smaller than that of the multilayer film by 18%. This was attributed to a much larger internal loss of WGP due to light absorption by metal wires. The internal losses of both reflective polarizers and the polarization conversion efficiency of the backlight were obtained numerically based on a phenomenological model. The optical performances of WGP were optimized by using a time-domain simulation technique. The luminance gain increased and was found to become comparable to, but slightly less than the case of the dielectric multilayer film with decreasing line width.

Fabrication of Three-Dimensional Reflective White Pattern using Dry-Film Resist

  • Jun, Hwa Joon;Na, Dae Gil;Kwon, Young Hoon;Kwon, Jin Hyuk
    • Journal of the Optical Society of Korea
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    • v.19 no.1
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    • pp.80-83
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    • 2015
  • White reflective patterns are very difficult to fabricate, due to the scattering and reflection of light, especially when the pattern size goes down to micron size. A reflective white barrier structure of height $50{\mu}m$ and width $80{\mu}m$ was fabricated using dry-film resist as an intermediate reverse pattern. The reverse dry-film resist pattern was coated with an $SiO_2$ layer by sputtering, to protect the resist from chemical attack by the radical molecules in UV white resin. The UV white resin was applied on the dry-film resist pattern and then cured with ultraviolet light. The fine three-dimensional reflective patterns were finished by removing the dry-film resist.

Fabrication of a Nano-Wire Grid Polarizer for Brightness Enhancement in TFT-LCD Display (TFT-LCD용 휘도 성능을 향상시키는 나노 와이어 그리드 편광 필름의 제작)

  • Huh, Jong-Wook;Nam, Su-Yong
    • Journal of the Korean Graphic Arts Communication Society
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    • v.29 no.3
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    • pp.105-124
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    • 2011
  • TFT-LCD consists of LCD panel on the top, circuit unit on the side and BLU on the bottom. The recent development issues of BLU-dependent TFT-LCD have been power consumption minimization, slimmerization and size maximization. As a result of this trend, LED is adopted as BLU instead of CCFL to increase brightness and to reduce thickness. In liquid crystal displays, the light efficiency is below 10% due to the loss of light in the path from a light source to an LCD panel and presence of absorptive polarizer. This low efficiency results in low brightness and high power consumption. One way to circumvent this situation is to use a reflective polarizer between backlight units and LCD panels. Since a nano-wire grid polarizer has been known as a reflective polarizer, an idea was proposed that it can be used for the enhancement of the brightness of LCD. The use of reflective polarizing film is increasing as edge type LED TV and 3D TV markets are growing. This study has been carried out to fabrication of the nano-wire grid polarizer(NWGP) and investigated the brightness enhancement of LCD through polarization recycling by placing a NWGP between an c and a backlight unit. NWGPs with a pitch of 200nm were fabricated using laser interference lithography and aluminum sputtering and wet etching. And The NWGP fabrication process was using by the UV imprinting and was applied to plastic PET film. In this case, the brightness of an LCD with NWGPs was 1.21 times higher than that without NWGPs due to polarization recycling.

Reflective Twist Nematic Liquid Crystal Display For High Reflectance.

  • Son, Ock-Soo;Park, Young-Il;Beak, Do-Hyoen;Son, Gon;Suh, Dong-Hea
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.292-294
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    • 2008
  • We have developed new reflective LCD for Mixed twist nematic LC mode with high quality image. We have found out an optimal twist angle of LC and optical film's axis by simulation. Also we measured electro-optic characteristics for new design panel. As a result, high reflectance and wide viewing angle characteristics were achieved.

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Designing low cost liquid crystal mode for Transflective LCD

  • Baek, Heume-Il;Ham, Mi-Sook;Ha, Kyung-Su;Kim, Dong-Guk;Shin, Hyun-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.556-559
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    • 2002
  • We designed a low cost optical structure of transflective LCD that uses only a half number of retardation films compared to general active matrix transflective LCD. The prototype embodied by this design shows reasonable reflective and transmissive performance. This design would provide us thinner, lighter and cheaper product due to its reduced retardation film structure.

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