KR19990025168A - 2-domain parallel alignment liquid crystal display - Google Patents
2-domain parallel alignment liquid crystal display Download PDFInfo
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- KR19990025168A KR19990025168A KR1019970046695A KR19970046695A KR19990025168A KR 19990025168 A KR19990025168 A KR 19990025168A KR 1019970046695 A KR1019970046695 A KR 1019970046695A KR 19970046695 A KR19970046695 A KR 19970046695A KR 19990025168 A KR19990025168 A KR 19990025168A
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- G02F1/00—Devices 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
- G02F1/01—Devices 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
- G02F1/13—Devices 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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/133753—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
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- G02F1/00—Devices 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
- G02F1/01—Devices 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
- G02F1/13—Devices 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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
- G02F1/133634—Birefringent elements, e.g. for optical compensation the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
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- G02F1/00—Devices 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
- G02F1/01—Devices 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
- G02F1/13—Devices 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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
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- G—PHYSICS
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- G02F1/00—Devices 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
- G02F1/01—Devices 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
- G02F1/13—Devices 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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/13378—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation
- G02F1/133784—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation by rubbing
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- G02F—OPTICAL 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
- G02F1/00—Devices 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
- G02F1/01—Devices 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
- G02F1/13—Devices 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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/13378—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation
- G02F1/133788—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation by light irradiation, e.g. linearly polarised light photo-polymerisation
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Abstract
2도메인(domain)으로 배향분할하여 평행배향하고, 보상필름을 사용하여 광시야각이 개선된 2도메인 평행배향 액정표시소자를 제공한다.The present invention provides a two-domain parallel alignment liquid crystal display device in which alignment is divided into two domains in parallel to perform parallel alignment, and an optical viewing angle is improved by using a compensation film.
본 발명의 2도메인 평행배향 액정표시소자는, 제1편광판을 구비한 제1기판과, 보상필름 및 제2편광판을 차례로 적층한 제2기판과, 상기 제1기판 위에 형성된 제1 및 제2배향방향을 갖는 제1배향막과, 상기 제2기판 위에 형성된 제1 및 제2배향방향을 갖는 제2배향막과, 상기 제1기판 및 제2기판 사이에 형성된 액정층으로 구성된다.The two-domain parallel alignment liquid crystal display of the present invention includes a first substrate having a first polarizing plate, a second substrate in which a compensation film and a second polarizing plate are stacked in this order, and first and second alignments formed on the first substrate. A first alignment film having a direction, a second alignment film having first and second alignment directions formed on the second substrate, and a liquid crystal layer formed between the first substrate and the second substrate.
Description
본 발명은 액정표시소자에 관한 것으로, 특히, 광시야각 특성이 우수한 2도메인 평행배향 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 two domain parallel alignment liquid crystal display device having excellent wide viewing angle characteristics.
종래에, 액정표시소자(Liquid Crystal Display Device, LCD)의 광시야각을 얻기 위한 배향분할방법에 있어서 전기광학 모드의 여러 가지가 제안되어 있다.Background Art Conventionally, various types of electro-optic modes have been proposed in an orientation splitting method for obtaining a wide viewing angle of a liquid crystal display device (LCD).
일반적으로, TN(Twisted Nematic) 액정표시소자는 브라운관에 가까운 고화질을 기대할 수 있기 때문에 대용량, 대면적화가 가능하다. 그러나, TN 액정표시소자는 시야각에 따라 각 계조표시(gray level)에서의 광투과도가 달라지는 특성이 있으므로, 이러한 고급화를 진행하는 데에는 시야각 특성의 개선이 필수적이다.In general, a TN (Twisted Nematic) liquid crystal display device can expect a high quality close to the CRT, so that a large capacity and a large area can be achieved. However, since the TN liquid crystal display device has a characteristic in which light transmittance at each gray level is changed depending on the viewing angle, it is necessary to improve the viewing angle characteristic in order to advance such an advanced process.
또한, 현재 널리 보급되고 있는 TN 액정표시소자는 편광판을 사용하고 있기 때문에 본질적으로 밝기가 부족하므로, 밝기의 개선과 더불어 시야각 확대(광시야각), 화면휘도 향상, 러빙가공이 없는 공정에 의한 생산처리의 개선 등의 연구개발과제가 존재한다.In addition, since TN liquid crystal display devices, which are widely used at present, use polarizing plates, they are inherently lacking in brightness. Therefore, the TN liquid crystal display device is improved in brightness, producing a wider viewing angle (wide viewing angle), improving screen brightness, and processing without rubbing. There are research and development tasks such as improvement of
특히, TN모드는 좌우방향의 시야각에 대해서는 광투과도가 대칭적으로 분포하지만, 상하방향에 대해서는 광투과도가 비대칭적으로 분포하기 때문에, 상하방향의 시야각에서는 이미지가 반전되는 범위가 발생되어 시야각이 좁아지는 문제가 있다.Particularly, in the TN mode, light transmittance is distributed symmetrically with respect to the viewing angle in the left and right directions, but light transmittance is distributed asymmetrically with respect to the up and down directions. There is a problem.
이러한 액정의 비등방성을 보완하기 위해 2도메인-TN모드 및 4도메인-TN모드가 제안된 바 있으나, 2도메인-TN모드는 콘트라스트비(contrast ratio)가 10 보다 높은 범위의 상하 시야각이 ±25°밖에 되지 않으며, 4도메인-TN모드의 경우는 상하좌우 시야각이 ±40°정도 밖에 되지 않는다는 문제점이 잔존하고, 결정적으로 제조공정이 복잡하다는 단점이 존재한다.2 domain-TN mode and 4 domain-TN mode have been proposed to compensate for the anisotropy of such liquid crystals, but the 2 domain-TN mode has a vertical viewing angle of ± 25 ° having a contrast ratio higher than 10. In the case of the 4 domain-TN mode, there is a problem that the vertical, horizontal, left and right viewing angles are about ± 40 °, and the manufacturing process is decisively complicated.
상기한 문제점을 해결하기 위해, 최근에는 액정표시소자의 광시야각을 목적으로 한 ECB(Electrically Controlled Birefringence) 모드가 제안되어 있다. ECB모드는, 액정셀에 전압을 인가하면, 액정의 유전이방성에 의해 액정분자의 배열이 변화하여 액정셀 중의 복굴절율이 변화하므로, 이렇게 액정셀의 복굴절율을 변화시켜 광투과율의 변화를 유도하는 방식이다.In order to solve the above problems, recently, an electrically controlled irefringence (ECB) mode for the wide viewing angle of a liquid crystal display device has been proposed. In the ECB mode, when a voltage is applied to a liquid crystal cell, the arrangement of liquid crystal molecules is changed by the dielectric anisotropy of the liquid crystal, and thus the birefringence of the liquid crystal cell is changed. That's the way.
이러한 ECB모드 중 대표적인 방식으로 VA(Vertical Alignment) 모드와 OCB(Optical Compensated Birefringence;π-Cell) 모드를 들 수 있다.Representative methods of such ECB mode include VA (Vertical Alignment) mode and OCB (Optical Compensated Birefringence; π-Cell) mode.
우선, VA모드는 유전율 이방성이 음인 액정(liquid crystal with negative dielectric anisotropy), 즉, 네가형 액정과 수직 배향막을 이용한 것이다. 이 VA모드는 기본이 되는 모노도메인 방식과, 전방위에서 광시야각을 실현한 배향분할 방식 두 가지가 있다.First, VA mode uses a liquid crystal with a negative dielectric anisotropy, that is, a negative liquid crystal and a vertical alignment layer. This VA mode has two basic mono-domain methods and an orientation division method that realizes a wide viewing angle in all directions.
도 1은 종래의 하나의 화소가 2도메인으로 형성된 VA모드 액정표시소자의 개략적인 구조를 나타내는 도면으로서, 액정셀의 구성은 상하 한 쌍의 유리기판(3, 3')에 배향막(5, 5')을 형성하여 수직 배향 처리하고, 그 배향막 사이에 네가형 액정(negative liquid crystal)(7)을 주입하고, 기판 양측에 편광판(1, 1')을 직교시켜 배치한다.FIG. 1 is a view showing a schematic structure of a VA mode liquid crystal display device in which one pixel is formed of two domains. The liquid crystal cell has an alignment layer 5, 5 on a pair of upper and lower glass substrates 3, 3 '. ') Is formed and subjected to the vertical alignment process, a negative liquid crystal 7 is injected between the alignment films, and the polarizing plates 1 and 1' are arranged orthogonally to both sides of the substrate.
전압무인가 상태는 네가형 액정분자가 수직으로 배향되어 있고, 편광판은 직교로 배치되어 있으므로 흑색바탕모드(normally black mode)를 표시한다. 반면에, 전압인가 상태는 네가형 액정분자의 전계에 대해 비스듬하게 배향하는 성질에 의해, 특정 방향으로 기울고, 액정셀 내의 리타데이션(retardation;ｄΔｎ, ｄ는 셀의 두께, Δｎ은 액정분자의 굴절률 이방성)이 변화하여 광이 투과된다.In the voltage-free state, the negative liquid crystal molecules are vertically aligned, and the polarizers are arranged orthogonally, so that they display a normally black mode. On the other hand, the voltage applied state is inclined in a specific direction due to the property of being oriented obliquely with respect to the electric field of the negative liquid crystal molecules, the retardation in the liquid crystal cell (dΔn, d is the thickness of the cell, and Δn is the refractive index of the liquid crystal molecules). Anisotropy) changes to transmit light.
특히, 도면과 같은 배향분할 방식은 전압인가 상태에서 액정분자가 서로 반대가 되도록 기울게 배향하며, 액정분자가 갖는 광학 이방성을 없애고 전방위의 시야각 특성을 향상시킨다.In particular, the orientation splitting method as shown in the drawing is inclined so that the liquid crystal molecules are opposite to each other in a voltage applied state, and eliminates optical anisotropy of the liquid crystal molecules and improves the viewing angle characteristic of the omnidirectional.
그러나, 상기 VA모드는 액정을 수직으로 배향시키기 때문에, 배향방식 자체로 인한 화학적, 물리적 불안정성이 존재하며, 유전율이 음인 네가형 액정만을 사용하여야 하므로 액정의 종류가 한정된다는 단점이 존재한다.However, since the VA mode orientates the liquid crystals vertically, there is a chemical and physical instability due to the alignment method itself, there is a disadvantage that the type of the liquid crystal is limited because only negative type liquid crystal having a negative dielectric constant should be used.
OCB모드는, 도 2에 나타낸 바와 같이, 유리기판(33, 33')에 형성한 배향막(35, 35') 부근에서는 상기한 유리기판과 프리틸트각(pretilted angle)을 형성하고 있지만, 양 배향막(35, 35')의 중간에서는 거의 90°를 이루게 되며 기판에 가까워지면서 점차 각도가 줄어드는 대칭적인 벤드구조로 되어 있어 시야각 특성이 향상된다.In the OCB mode, as shown in Fig. 2, the pretilted angle is formed with the above-described glass substrate in the vicinity of the alignment films 35 and 35 'formed on the glass substrates 33 and 33', but both alignment films are formed. In the middle of (35, 35 '), the angle of view is almost 90 ° and the symmetrical bend structure gradually decreases as it approaches the substrate, improving the viewing angle characteristic.
상기한 바와 같이 액정(37)이 배향막과 90°를 이루는 액정의 벤드배향은, 배향막에 배향방향을 형성하고, 프리틸트각을 형성한 다음 액정을 프리틸트각에 따라 적절히 조절하여 주입함으로써 이루어진다. 그리고, 상기한 벤드 배향된 액정셀에 전기장을 인가해 주면 액정분자들이 전기장에 따라 움직이기 때문에 유효굴절율이 변하게 되어 투과율 역시 변하게 된다.As described above, the bend alignment of the liquid crystal in which the liquid crystal 37 forms 90 ° with the alignment film is performed by forming an alignment direction on the alignment film, forming a pretilt angle, and then injecting the liquid crystal appropriately according to the pretilt angle. When the electric field is applied to the bend-oriented liquid crystal cell, the effective refractive index changes because the liquid crystal molecules move according to the electric field, and the transmittance also changes.
따라서, 액정분자가 상하기판 사이에서 서로 대칭으로 분포하여, 도 2에 나타낸 바와 같은 벤드배향이 이루어져 상하 또는 좌우방향의 비대칭이 사라지게 되므로, 기존의 액정셀에 비해 시야각 특성이 크게 향상되며, 배향분할을 하지 않고도 광시야각 특성을 얻을 수 있다.Therefore, the liquid crystal molecules are symmetrically distributed between the upper and lower substrates, so that the bend alignment is made as shown in FIG. 2 so that the asymmetry of the vertical and horizontal directions disappears, so that the viewing angle characteristics are greatly improved compared to the conventional liquid crystal cell, and the alignment is divided. Wide viewing angle characteristics can be obtained without
그러나, 이러한 벤드구조의 OCB모드는 벤드구조를 인위적으로 만들어 주기 위한 부가적인 전압을 필요로 하며, 벤드구조 자체의 불안정성 등의 문제점이 여전히 남아있다.However, the OCB mode of the bend structure requires an additional voltage to artificially make the bend structure, and problems such as instability of the bend structure itself remain.
본 발명은 상기한 종래 기술의 문제점을 감안하여 이루어진 것으로서, 화소를 2개의 도메인으로 배향분할하여 평행배향하고, 보상필름을 사용하는 것에 의해 광시야각이 개선된 2도메인 평행배향 액정표시소자를 제공하는 것을 목적으로 한다.SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and provides a two-domain parallel alignment liquid crystal display device in which a pixel is aligned in parallel to two domains to be aligned in parallel, and a wide viewing angle is improved by using a compensation film. For the purpose of
상기한 목적을 달성하기 위해, 본 발명에 따른 2도메인 평행배향 액정표시소자는, 제1편광판을 구비한 제1기판과, 보상필름 및 제2편광판을 차례로 적층한 제2기판과, 상기 제1기판 위에 형성된 제1 및 제2배향방향을 갖는 제1배향막과, 상기 제2기판 위에 형성된 제1 및 제2배향방향을 갖는 제2배향막과, 상기 제1기판 및 제2기판 사이에 형성된 액정층으로 구성된다.In order to achieve the above object, the two-domain parallel alignment liquid crystal display device according to the present invention includes a first substrate having a first polarizing plate, a second substrate in which a compensation film and a second polarizing plate are sequentially stacked, and the first substrate. A first alignment film having first and second alignment directions formed on the substrate, a second alignment film having first and second alignment directions formed on the second substrate, and a liquid crystal layer formed between the first substrate and the second substrate It consists of.
본 발명에 따른 2도메인 평행배향 액정표시소자는 2도메인만으로 우수한 광시야각을 실현할 수 있으므로 공정을 단순화시킬 수 있고, 액정층의 액정이 수평배향이므로 배향 방식 자체로서 화학적, 물리적으로 안정하며, 자연스러운 평행배향이므로 신뢰성, 공정안정성면에서 우수하다. 또한, 단순한 구조의 보상필름을 사용함으로써 방위각에 따른 광학특성의 상이함을 해결하여 사용자의 시야각변화에 관계없이 균일한 광학적 특성을 얻는 효과가 있으므로 훨씬 넓은 광시야각을 구현할 수 있다.The two-domain parallel alignment liquid crystal display device according to the present invention can realize an excellent wide viewing angle with only two domains, thereby simplifying the process, and since the liquid crystal of the liquid crystal layer is horizontally aligned, chemically and physically stable as the alignment method itself, and naturally parallel. Since it is an orientation, it is excellent in reliability and process stability. In addition, by using a compensation film of a simple structure to solve the difference in the optical characteristics according to the azimuth angle, it is possible to achieve a much wider viewing angle because there is an effect of obtaining a uniform optical characteristics regardless of the change in the viewing angle of the user.
도 1은, 종래 VA모드 액정표시소자의 개략적인 구조를 나타내는 단면도.1 is a cross-sectional view showing a schematic structure of a conventional VA mode liquid crystal display device.
도 2는, 종래 OCB모드 액정표시소자의 개략적인 구조를 나타내는 단면도.2 is a cross-sectional view showing a schematic structure of a conventional OCB mode liquid crystal display device.
도 3은, 본 발명의 2도메인 평행배향 액정표시소자의 개략적인 구조를 나타내는 사시도.Fig. 3 is a perspective view showing a schematic structure of a two domain parallel alignment liquid crystal display device of the present invention.
도 4는, 본 발명의 2도메인 평행배향 액정표시소자의 개략적인 구조를 나타내는 단면도.Fig. 4 is a sectional view showing a schematic structure of a two domain parallel alignment liquid crystal display device of the present invention.
도 5는, 본 발명의 2도메인 평행배향 액정표시소자의 액정의 배향방향을 나타내는 도면.Fig. 5 is a diagram showing the alignment direction of liquid crystals of the two domain parallel alignment liquid crystal display device of the present invention.
* 도면의 주요부분에 대한 부호의 설명 *Explanation of symbols on the main parts of the drawings
51 : 제1편광판 151 : 제2편광판51: first polarizing plate 151: second polarizing plate
53 : 제1기판 153 : 제2기판53: first substrate 153: second substrate
55 : 제1배향막 155 : 제2배향막55: first alignment layer 155: second alignment layer
57 : 액정 59 : 보상필름57 liquid crystal 59 compensation film
이하, 첨부한 도면을 참조하여 본 발명에 따른 2도메인 평행배향 액정표시소자를 상세하게 설명한다.Hereinafter, a two domain parallel alignment liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.
도 3은 본 발명에 따른 하나의 화소가 2도메인으로 형성된 2도메인 평행배향 액정표시소자의 개략적인 구조를 나타내는 사시도이다.3 is a perspective view showing a schematic structure of a two domain parallel alignment liquid crystal display device in which one pixel is formed of two domains according to the present invention.
동일 도면에 나타내는 바와 같이, 본 발명에 따른 액정표시소자는 제1편광판(51)이 적층된 제1기판(53)과, 보상필름(59) 및 제2편광판(151)이 차례로 적층된 제2기판(153)과, 상기 제1기판 및 제2기판 사이의 액정층(57)으로 구성된다.As shown in the same drawing, the liquid crystal display according to the present invention includes a first substrate 53 on which the first polarizing plate 51 is stacked, and a second layer on which the compensation film 59 and the second polarizing plate 151 are sequentially stacked. And a liquid crystal layer 57 between the substrate 153 and the first and second substrates.
또한, 상기한 구조의 2도메인 평행배향 액정표시소자는, 하나의 화소를 두 개의 배향방향을 갖는 2도메인으로 형성하여 전압인가시에 각 도메인의 액정층 중간층의 액정분자의 틸트각이 서로 반대방향으로 되게 한다. 이 때, 제1 및 제2기판의 평균 프리틸트각의 크기는 0°보다 크고 45°보다 작게 설정한다.In addition, in the two-domain parallel alignment liquid crystal display device having the above-described structure, the tilt angles of the liquid crystal molecules of the intermediate layer of the liquid crystal layer of each domain when the voltage is applied are formed by forming one pixel into two domains having two alignment directions. To be. At this time, the magnitude of the average pretilt angle of the first and second substrates is set larger than 0 ° and smaller than 45 °.
상기 2도메인의 형성은 러빙(rubbing) 등의 기계적인 배향 또는 광배향을 혼용하는 방법이 가능하다. 러빙을 이용하는 방법은, PI(polyimide)를 기판에 도포하여 배향하고, 광배향을 이용하는 방법은, 상기 제1기판(53) 및 제2기판(153) 위에 PVCN(polyvinyl cinnamate)계 물질 또는 PSCN(polysiloxane cinnamate)계 물질 등과 같은 고분자물질을 도포하고, 그 위에 자외선 조사에 의한 광배향을 실시하여 액정분자의 배향방향이 x축방향이 되도록 배향막(55, 155)을 형성한다(이 때 배향의 정도는 액정의 물성과 요구되는 조건에 따라 적절하게 조절한다.).Formation of the two domains may be a method of mixing mechanical orientation or photoalignment such as rubbing. The method of using rubbing is applied by applying PI (polyimide) to the substrate, and the method of using photo-alignment is a polyvinyl cinnamate (PVCN) -based material or PSCN (on the first substrate 53 and the second substrate 153) A polymer material such as a polysiloxane cinnamate-based material or the like is applied, and photo-alignment by ultraviolet irradiation is performed thereon to form alignment layers 55 and 155 so that the alignment direction of the liquid crystal molecules is in the x-axis direction (the degree of alignment at this time). Is appropriately adjusted according to the properties of the liquid crystal and the required conditions).
더불어, 상기 제1기판(53)에 형성된 틸트각과 상기 제2기판(153)에 형성된 틸트각을 서로 다르게 형성할 수도 있다. 예를 들어, 상기 제1기판의 틸트각 또는 상기 제2기판의 틸트각 중 하나의 각을 0°로 하고, 나머지 하나의 각을 그 이상으로 형성하는 것이 가능하다.In addition, the tilt angle formed on the first substrate 53 and the tilt angle formed on the second substrate 153 may be different from each other. For example, it is possible to set the angle of one of the tilt angles of the first substrate and the tilt angle of the second substrate to 0 °, and to form the other one more than that.
그리고, 상기 제1기판(53) 아래에는 제1편광판(51)을 부착하고, 상기 제2기판(153) 위에는 보상필름(59)과 제2편광판(151)을 차례로 적층한다. 여기서 상기한 제1 및 제2편광판의 편광방향은 서로 직교하며, 도 5에 나타낸 바와 같이 액정의 배향방향(azimuthal direction)과는 각각 45°를 이루고 있다.In addition, a first polarizing plate 51 is attached to the first substrate 53, and a compensation film 59 and a second polarizing plate 151 are sequentially stacked on the second substrate 153. Here, the polarization directions of the first and second polarizing plates are orthogonal to each other, and as shown in FIG. 5, they are 45 ° to the azimuthal direction of the liquid crystal.
더불어, 본 발명의 상기한 보상필름(59, retardation film)은 도면상의 x축방향(액정의 배향방향과 동일방향)에 비해 y축방향의 편광이 25∼100㎚만큼 (+)의 위상보상이 되게 하고, xy평면에 비해 z축방향으로 0∼500㎚만큼 (-)의 위상보상이 되게 하는 기능을 가진다.In addition, the compensation film 59 of the present invention has a (+) phase compensation of the polarization in the y-axis direction by 25 to 100 nm compared to the x-axis direction (the same direction as the alignment direction of the liquid crystal) on the drawing. And a phase compensation of (-) by 0 to 500 nm in the z-axis direction compared to the xy plane.
따라서, 본 발명의 보상필름(59)은 기판에 수직인 방향과 시야각 변화에 따른 방향에서 사용자가 느끼는 위상차를 보상해주는 역할을 하며, 하나의 화소를 2도메인으로 형성하는 것에 의해 더욱 효과적으로 상하방향의 시야각을 보상할 수 있다.Therefore, the compensation film 59 of the present invention serves to compensate for the phase difference felt by the user in the direction perpendicular to the substrate and the direction of the viewing angle change, and more effectively by forming one pixel in two domains. The viewing angle can be compensated.
계속해서, 상기 제1기판(53)과 제2기판(153) 사이에 액정(57)을 주입하여 액정표시소자를 완성한다. 액정은 유전율이 (+)인 액정을 사용하여, 배향막 부근에서는 프리틸트각을 형성하고 있지만, 전압인가시에는 기판과 수직하게 형성되는 전계에 따라 양 배향막의 중간에서는 액정이 거의 90°를 이루게 된다.Subsequently, a liquid crystal 57 is injected between the first substrate 53 and the second substrate 153 to complete the liquid crystal display device. The liquid crystal uses a liquid crystal having a dielectric constant of (+) to form a pretilt angle in the vicinity of the alignment film, but when voltage is applied, the liquid crystal is almost 90 ° in the middle of both alignment films depending on the electric field formed perpendicular to the substrate. .
상기한 액정층(57)의 리타데이션(ｄΔｎ)은 0.15∼0.35㎛가 되게 하고, 전압무인가 상태에서는 백색바탕모드(normally white mode)이고, 전압인가 상태에서는 흑색모드이나, 백색바탕모드에서의 전압은 완전 흑색모드에서의 전압의 0∼40%의 범위 내에서 정하도록 한다.The retardation (dΔn) of the liquid crystal layer 57 is 0.15 to 0.35 mu m, and is normally white mode in a voltage-free state, and black mode or voltage in a white background mode in a voltage-applied state. Is set within the range of 0 to 40% of the voltage in all black mode.
또한, 본 발명의 2도메인 평행배향 액정표시소자에 있어서, 상하 시야각 방향과 액정배향방향(azimuthal direction)이 이루는 각도는 0∼60°의 범위로 하며, 30°정도가 바람직하다.In the two-domain parallel alignment liquid crystal display device of the present invention, the angle formed by the vertical viewing angle direction and the liquid crystal alignment direction (azimuthal direction) is in the range of 0 to 60 °, and preferably about 30 °.
도면으로 나타내지는 않았지만, 본 발명의 액정표시소자는 콘트라스트비가 10 보다 높은 범위에서 상하좌우 ±45°의 시야각 영역을 나타내는데, 이것은 4도메인 TN액정표시소자가 ±40°정도의 시야각 영역을 갖는 것에 비하여 매우 우수한 특성이라 할 수 있다.Although not shown in the drawings, the liquid crystal display device of the present invention exhibits a viewing angle region of up to left, right and up to +/- 45 degrees in a contrast ratio of more than 10, which is higher than that of a four-domain TN liquid crystal display device having a viewing angle region of about ± 40 degrees. It is a very good characteristic.
그리고, 또 다른 실시예로서, 상기한 과정에서의 배향막을, 제1기판 또는 제2기판 중 어느 한 쪽에만 형성하여 배향할 수 있으며, 이러한 배향막 또한, 러빙(rubbing) 등의 기계적인 배향 또는 광배향을 혼용하는 방법이 가능하다. 그 외의 것은 상기한 바와 동일한 방법으로 2도메인 평행배향 액정표시소자를 제조할 수 있다.In another embodiment, the alignment layer in the above process may be formed and oriented only on either the first substrate or the second substrate, and the alignment layer may also be subjected to mechanical alignment or light such as rubbing. It is possible to mix orientation. Otherwise, a two domain parallel alignment liquid crystal display device can be manufactured by the same method as described above.
본 발명에 따른 2도메인 평행배향 액정표시소자는, 2도메인만으로 4도메인 TN 액정표시소자 보다 우수한 광시야각을 실현할 수 있으며, 따라서 공정을 단순화시킬 수 있다. 그리고, VA모드와 같은 수직배향이 아닌 수평배향이므로, 배향 방식 자체가 화학적, 물리적으로 안정하며, 유전율이 음인 네가형 액정만을 사용하는 VA모드에 비해 신뢰성, 공정안정성면에서 우수하다.The two domain parallel alignment liquid crystal display device according to the present invention can realize a wider viewing angle than the four domain TN liquid crystal display device with only two domains, thus simplifying the process. In addition, since the vertical alignment is not the vertical alignment as in the VA mode, the alignment method itself is chemically and physically stable, and is superior in terms of reliability and process stability compared to the VA mode using only negative type liquid crystal having a negative dielectric constant.
또한, 벤드구조를 인위적으로 만들어 주기 위해 부가적인 전압인가가 요구되는 OCB모드에 비해 자연스러운 평행배향이므로, 벤드구조 자체의 불안정성 및 제조의 어려움 등의 문제점을 극복할 수 있다.In addition, since the parallel alignment is natural compared to the OCB mode in which additional voltage application is required to artificially make the bend structure, problems such as instability of the bend structure itself and manufacturing difficulties may be overcome.
더불어, 본 발명의 2도메인 평행배향 액정표시소자는, 종래의 광시야각용 필름보다 단순한 구조의 보상필름을 사용함으로써 방위각에 따른 광학특성의 상이함을 해결하여 사용자의 시야각변화에 관계없이 균일한 광학적 특성을 얻는 효과가 있다.In addition, the two-domain parallel alignment liquid crystal display device of the present invention uses a compensation film having a simpler structure than the conventional wide viewing angle film to solve the difference in optical characteristics according to the azimuth angle so that the optical angle is uniform regardless of the change of the viewing angle of the user. This has the effect of gaining character.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20010053976A (en) * | 1999-12-02 | 2001-07-02 | 윤종용 | a liquid crystal display having multi-domains |
| KR100462017B1 (en) * | 1997-12-31 | 2005-06-07 | 삼성전자주식회사 | Wide viewing angle liquid crystal display device |
| KR100591547B1 (en) * | 2000-05-08 | 2006-06-19 | 엘지.필립스 엘시디 주식회사 | Multi-domain Optically Compensated Birefringence mode Liquid Crystal Display Device |
| KR100806882B1 (en) * | 2001-04-26 | 2008-02-22 | 삼성전자주식회사 | A liquid crystal display panel having wide viewing angle and a thin film transistor array panel |
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| CN104995552B (en) | 2012-12-14 | 2017-08-29 | 株式会社Lg化学 | liquid crystal device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100462017B1 (en) * | 1997-12-31 | 2005-06-07 | 삼성전자주식회사 | Wide viewing angle liquid crystal display device |
| KR20010053976A (en) * | 1999-12-02 | 2001-07-02 | 윤종용 | a liquid crystal display having multi-domains |
| KR100591547B1 (en) * | 2000-05-08 | 2006-06-19 | 엘지.필립스 엘시디 주식회사 | Multi-domain Optically Compensated Birefringence mode Liquid Crystal Display Device |
| KR100806882B1 (en) * | 2001-04-26 | 2008-02-22 | 삼성전자주식회사 | A liquid crystal display panel having wide viewing angle and a thin film transistor array panel |
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