KR960003477B1 - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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Publication number
KR960003477B1
KR960003477B1 KR1019920023513A KR920023513A KR960003477B1 KR 960003477 B1 KR960003477 B1 KR 960003477B1 KR 1019920023513 A KR1019920023513 A KR 1019920023513A KR 920023513 A KR920023513 A KR 920023513A KR 960003477 B1 KR960003477 B1 KR 960003477B1
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South Korea
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liquid crystal
phase difference
crystal cell
crystal display
display device
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KR1019920023513A
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Korean (ko)
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KR940015560A (en
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김완수
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엘지전자주식회사
구자홍
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Priority to KR1019920023513A priority Critical patent/KR960003477B1/en
Priority to JP30405693A priority patent/JP3342940B2/en
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    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells

Abstract

a nematic liquid crystal cell having a twist angle of 180 to 270≰; a phase delay compensating film positioned on the upper portion of the nematic liquid crystal cell, for constantly increasing a double refraction phase difference from a lower side having a low phase difference to an upper side having a high phase difference; and a polarization film disposed on the lower portion of the liquid crystal cell and the upper portion of the phase delay compensating film, for transmitting light from the liquid crystal cell.

Description

액정표시장치LCD Display

제1도는 종래의 액정표시장치의 부품배치도.1 is a component arrangement diagram of a conventional liquid crystal display device.

제2도는 종래의 액정표시장치에서의 위상지연보상 필름의 상하 방향으로의 복굴절 위상차를 나타낸 그래프.2 is a graph showing the birefringence phase difference in the vertical direction of the phase delay compensation film in the conventional liquid crystal display device.

제3도는 종래의 액정표시장치의 시야각을 나타낸 그래프.3 is a graph showing a viewing angle of a conventional liquid crystal display.

제4도는 액정표시장치에서 위상지연보상 필름의 복굴절 위상차에 따른 콘트리스트비를 나타낸 그래프.4 is a graph showing the contrast ratio according to the birefringence phase difference of the phase delay compensation film in the liquid crystal display device.

제5도는 종래의 액정표시장치에서 위상지연보상 필름의 시야각에 따른 콘트리스트비를 나타낸 그래프.5 is a graph showing the contrast ratio according to the viewing angle of the phase delay compensation film in the conventional liquid crystal display device.

제6도는 액정표시장치에서 본 발명에 따른 위상지연보상 필름을 채용했을때의 복굴절 위상차를 나타낸 그래프.6 is a graph showing birefringence retardation when the phase delay compensation film according to the present invention is employed in a liquid crystal display device.

제7도는 액정표시장치에서 본 발명에 따른 위상지연보상 필름을 채용했을때의 복굴절 위상차를 나타낸 그래프.7 is a graph showing the birefringence phase difference when the phase delay compensation film according to the present invention is adopted in the liquid crystal display device.

* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings

1 : 액정셀 2 : 위상지연보상필름1: liquid crystal cell 2: phase delay compensation film

3 : 편광필름3: polarizing film

본 발명은 액정표시장치에 관한 것으로, 특히 상하 방향으로 일정하게 변화하는 복굴절 위상차를 갖는 필름을 사용하여 시야각에 다른 콘트리스트비를 향상시킨 필름형 에스티엔(STN) 액정표시소자에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a film type styrene (STN) liquid crystal display device having an improved contrast ratio in a viewing angle by using a film having a birefringent retardation constantly changing in the vertical direction.

휴대용 컴퓨터 등의 표시장치는 일반적으로 단순 매트릭스 방식의 액정표시장치를 일반적으로 사용하고 있으며, 이러한 액정표시장치는 액정분자의 트위스트각을 180°∼270°으로 하는 STN(Super Twisted Namatic)모드를 택하고 있다. 이와같은 STN 모드에서 칼라화된 정보를 표시하는 전단계로 흑백정보를 표시하기 위해서 상업적으로 광범위하게 사용되는 방법은 2매의 위상지연보상 필름을 사용한 필름 STN(Film Super Twisted Nematic)액정표시장치이다.Display devices, such as portable computers, generally use a simple matrix type liquid crystal display device, and the liquid crystal display device adopts a STN (Super Twisted Namatic) mode in which the twist angle of liquid crystal molecules is 180 ° to 270 °. Doing. A widely used method for displaying black and white information in the previous step of displaying colorized information in the STN mode is a film STN (Film Super Twisted Nematic) liquid crystal display using two phase delay compensation films.

제1도는 종래의 필름 STN 액정표시장치의 구성을 도시하고 있다. 그 구조는 액정셀(1), 위상지연보상필름(2) 및 편광필름(3)으로 되어 있으며, 제1a도와 같이 2매의 위상지연보상필름(2)을 액정셀의 양면에 한개씩 배치시키는 형태가 있다. 위상지연보상필름(2)은 액정셀(1)을 통과하여 타원형으로 편광된 빛의 파장에 따른 위상을 지연시켜서 편광필름(3)을 통과하여 최종적으로 나오기전에 빛을 편광전의 상태로 복원시키는 역할을 한다.1 shows the structure of a conventional film STN liquid crystal display device. The structure consists of a liquid crystal cell (1), a phase delay compensation film (2), and a polarizing film (3), and arranges two phase delay compensation films (2) one by one on both sides of the liquid crystal cell as shown in FIG. There is. The phase delay compensation film (2) delays the phase according to the wavelength of the light polarized by the ellipse through the liquid crystal cell (1) and restores the light to the state before polarization before finally exiting through the polarizing film (3). Do it.

이와같은 방식의 보상작용에 의한 흑백표시의 실현은 실제로 액정셀(1)의 복굴절 위상차, 트위스트각과 위상지연보상필름(2)의 복굴절 위상차(R), 광축의 각도 그리고 편광필름의 투과축의 각도등 여러 설계 피라미터의 적절하고 최적화된 배치에 의해 실현할 수 있다.The realization of the black and white display by the compensation action in this manner is actually the birefringence phase difference of the liquid crystal cell 1, the twist angle and the birefringence phase difference R of the phase delay compensation film 2, the angle of the optical axis and the angle of the transmission axis of the polarizing film. This can be achieved by proper and optimized placement of several design parameters.

이렇게 구성된 종래의 필름 STN 액정표시장치에서는 제2도에 도시된 그래프와 같이 복굴절 위상차가 상하 및 좌우 방향으로 일정한 위상지연보상필름(2)을 사용한다. 그리고 실제로 액정패널을 바라볼 때에는 제3도에 도시된 바와같이 상하방향으로 약 10°정도의 시각차가 나타나는데, 최적의 콘트리스트비를 내는 복굴절 위상차는 제4도의 그래프와 같이 각각의 시야각 위차마다 다르므로, 시야각이 0°에서 가장 큰 콘트리스트비를 갖도록 복굴절 위상차가 상하 방향으로 일정한 위상차 필름을 사용한 경우에 종래의 제5도에 도시한 바와같이 시야각에 따라 콘트리스트비의 저하가 존재하는 것은 피할 수 없는 문제이다.In the conventional film STN liquid crystal display device configured as described above, a phase retardation compensation film 2 having a birefringent phase difference constant in the up, down, left, and right directions is used as shown in FIG. 2. In fact, when looking at the liquid crystal panel, as shown in FIG. 3, there is a visual difference of about 10 ° in the vertical direction, and the birefringence phase difference that gives the optimum contrast ratio is different for each viewing angle difference as shown in the graph of FIG. Therefore, when a birefringent retardation film having a constant birefringence retardation in the up and down direction is used to have the largest contrast ratio at 0 °, a decrease in the contrast ratio may be avoided depending on the viewing angle as shown in FIG. It can't be a problem.

본 발명은 위상지연보상필름을 사용하는 액정표시장치에서 시야각에 따른 콘트리스트비의 저하를 해결하기 위한 것으로 시야각에 따라 최대의 콘트리스트비를 갖도록 위상지연보상 필름의 복굴절 위상차를 보상필름의 부위마다 다르게 구성함을 특징으로 한다.The present invention is to solve the degradation of the contrast ratio according to the viewing angle in the liquid crystal display device using the phase delay compensation film, so that the birefringent retardation of the phase delay compensation film for each part of the compensation film to have the maximum contrast ratio according to the viewing angle. It is characterized by a different configuration.

상기 목적을 달성하기 위한 본 발명은 제6도에 도시한 바와같이 위상지연보상필름(2)의 수평 중앙선, 즉 시야각 0°인 곳에서 콘트리스트비를 최대로 할 수 있는 복굴절 위상차 R0를 갖도록 하고, 상기 시야각이 낮아질수록 복굴절 위상차 R0을 선형적으로 감소시켜 상기 위상지연보상필름(2)의 최하단에서의 복굴절 위상차가 R0-△R가 되도록 하며, 상기 시야각이 높아질수록 복굴절 위상차 R0을 선형적으로 증가시켜 상기 위상지연보상필름(2)의 최상단에서는 복굴절 위상차가 R0+△R가 되도록 하는 위상차필름 두매를 액정셀 일측이나 또는 액정셀 양측에 설치하여 구성한다.The present invention for achieving the above object has a birefringent phase difference R 0 that can maximize the contrast ratio in the horizontal center line of the phase delay compensation film 2, that is, the viewing angle 0 ° as shown in FIG. The birefringent phase difference R 0 is linearly reduced as the viewing angle is lowered such that the birefringence phase difference at the lowest end of the phase delay compensation film 2 becomes R 0 -ΔR, and the birefringence phase difference R 0 is increased as the viewing angle is increased . Is linearly increased so that two phase retardation films having birefringence phase difference R 0 + ΔR are arranged on one side of the liquid crystal cell or on both sides of the liquid crystal cell at the top end of the phase delay compensation film 2.

이때 상기한 시야각 0°에서는 복굴절 위상차 R0는 일반적으로 300nm 내지 450nm이며 본 발명의 유효 시야각 범위를 ±10°로 할때 복굴절 위상차 △R은 상기 R0의 1/5 내지 1/12 정도이다. 상기한 구성으로 된 바라명은 제4도에서 알수 있듯이 복굴절 위상차가 R0-△R일대 콘트리스트비가 최대가 되고(제4도(A)) 복굴절 위상차가 커질수록 콘트리스트비가 하강하다가 R0-1/2 △R 지점부터 R0에 접근할수록 콘트리스트비가 급격히 증가하여 R0에서 다시 최대의 콘트리스트비를 갖게 되며(B), 복굴절위상차가 R0보다 커지면 다시 하강하기 시작한다. 그러나 R0+1/2 △R 지점부터 다시 콘트리스트비가 상승하여 R0+△R인 지점에 도달하면 최대의 콘트리스트비를 갖게 되는 것이다.(c).At this time, the birefringence phase difference R 0 is generally 300 nm to 450 nm at the viewing angle 0 °, and the birefringence phase difference ΔR is about 1/5 to 1/12 of the R 0 when the effective viewing angle range of the present invention is ± 10 °. As can be seen from Fig. 4, the birefringence phase difference becomes the maximum R 0 -ΔR one-to-one contrast ratio (Fig. 4 (A)), and as the birefringence phase difference increases, the contrast ratio decreases and then R 0 -1. As we approach R 0 from the point / 2 ΔR, the contrast ratio increases rapidly, and the maximum contrast ratio is again obtained at R 0 (B). When the birefringence difference becomes larger than R 0 , it starts to fall again. However, when the contrast ratio rises again from the point R 0 +1/2 ΔR and reaches the point where R 0 + ΔR, the maximum contrast ratio is obtained (c).

상기와 같이 동작하는 본 발명은 제7도에서 알수있듯이 시야각이 0°인 지점에서 콘트리스트비가 최대가 되고 시야각이 증가하거나 감소할때도 종래와는 달리 일정 시야각 한도(±10°)까지는 거의 일정한 콘트리스트비를 유지하게된다. 상기한 바와같이 본 발명은 광범위한 시야각에 대하여 높고 일정한 콘트리스트비를 갖게되는 효과가 있다.As can be seen from FIG. 7, the present invention operates as described above, even when the contrast ratio is maximized at the point of view angle of 0 ° and the view angle increases or decreases, which is almost constant up to a certain viewing angle limit (± 10 °). Maintain the list ratio. As described above, the present invention has the effect of having a high and constant contrast ratio for a wide range of viewing angles.

Claims (2)

트위스트각이 180°내지 270°인 네마틱 액정셀(1)과, 상기 네마틱 액정셀(1) 상부에 위치하고, 시야각이 0°일때의 복굴절 위상차(R0)를 중심으로 작은 위상차(R0-△R)를 갖는 하측면에서 큰 위상차(R0+△R)를 갖는 상측면까지 일정하게 복굴절 위상차가 증가하는 위상지연보상 필름(2)과, 상기 액정셀(1)의 하부와 위상지연보상 필름(2)의 상부에 위치하여 액정셀(1)로 부터의 광을 투과시키는 편광필름(3)을 구비한 것을 특징으로 하는 액정표시장치.Small phase difference (R 0 ) centered on the nematic liquid crystal cell (1) having a twist angle of 180 ° to 270 ° and located above the nematic liquid crystal cell (1) and centered on the birefringent phase difference (R 0 ) when the viewing angle is 0 ° . A phase delay compensation film 2 in which the birefringence phase difference is constantly increased from the lower side having -ΔR to the upper side having a large phase difference (R 0 + ΔR), the lower portion and the phase delay of the liquid crystal cell 1 And a polarizing film (3) positioned above the compensation film (2) to transmit light from the liquid crystal cell (1). 제1항에 있어서, R0는 300nm∼450nm의 사이값을 가지며 △R은 R0/5∼R0/10의 값을 갖는 액정표시장치.The method of claim 1 wherein, R 0 has a value of between 300nm~450nm △ R is the liquid crystal display device having a value of R 0 / 5~R 0/10.
KR1019920023513A 1992-12-07 1992-12-07 Liquid crystal display device KR960003477B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1019920023513A KR960003477B1 (en) 1992-12-07 1992-12-07 Liquid crystal display device
JP30405693A JP3342940B2 (en) 1992-12-07 1993-12-03 Liquid crystal display

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Application Number Priority Date Filing Date Title
KR1019920023513A KR960003477B1 (en) 1992-12-07 1992-12-07 Liquid crystal display device

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KR960003477B1 true KR960003477B1 (en) 1996-03-14

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KR100342048B1 (en) * 1999-08-20 2002-06-27 김순택 Semipermeable LCD
US8198802B2 (en) 2008-07-25 2012-06-12 Samsung Mobile Display Co., Ltd. Organic light emitting diode display for suppressing reflection of external light
US8058783B2 (en) 2008-07-25 2011-11-15 Samsung Mobile Display Co., Ltd. Organic light emitting diode display for suppressing reflection of external light
US8169386B2 (en) 2008-08-19 2012-05-01 Samsung Mobile Display Co., Ltd. Organic light emitting diode display
KR100965258B1 (en) * 2008-08-27 2010-06-22 삼성모바일디스플레이주식회사 Organic light emitting diode display

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