KR20080103693A - Backlight unit - Google Patents

Backlight unit Download PDF

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Publication number
KR20080103693A
KR20080103693A KR1020070050724A KR20070050724A KR20080103693A KR 20080103693 A KR20080103693 A KR 20080103693A KR 1020070050724 A KR1020070050724 A KR 1020070050724A KR 20070050724 A KR20070050724 A KR 20070050724A KR 20080103693 A KR20080103693 A KR 20080103693A
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South Korea
Prior art keywords
light
diffusion layer
backlight unit
liquid crystal
light source
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KR1020070050724A
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Korean (ko)
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KR101327852B1 (en
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문제영
한상호
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엘지디스플레이 주식회사
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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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • G02F1/133604Direct backlight with lamps
    • 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • G02F1/133606Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • G02F1/133611Direct backlight including means for improving the brightness uniformity
    • 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • G02F1/133606Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

A backlight unit is provided to improve the viewing angle characteristics by improving the luminance uniformity. A backlight unit comprises a diffuse sheet formed with a light source, a prism sheet, and a top/bottom diffusion layer. The light source(23) generates light. A prism sheet(27) located upper part of the light source condenses the light from the light source. A light diffusing sheet located on the prism sheet diffuses the light from the prism sheet. The light diffusing sheet has an upper diffusing sheet and a lower diffusing sheet.

Description

백라이트 유닛{Backlight unit}Backlight unit

도 1은 본 발명에 따른 백라이트 유닛을 도시한 분해 사시도1 is an exploded perspective view showing a backlight unit according to the present invention;

도 2는 본 발명에 따른 백라이트 유닛의 확산시트를 도시한 단면도2 is a cross-sectional view showing a diffusion sheet of a backlight unit according to the present invention.

도 3a 및 도 3b는 상부 확산층 및 하부 확산층으로 입사되는 광을 도시한 단면도3A and 3B are cross-sectional views showing light incident on the upper and lower diffusion layers.

도 4a 및 도 4b는 종래 기술의 확산 시트와 본 발명의 확산시트를 각각 적용한 액정표시장치에서 상하좌우에서 디스플레이되는 화상을 도시한 사진들4A and 4B are photographs showing images displayed up, down, left, and right in a liquid crystal display device to which a diffusion sheet of the prior art and a diffusion sheet of the present invention are applied, respectively.

<도면의 주요부분에 대한 부호의 설명><Description of the code | symbol about the principal part of drawing>

20: 백라이트 유닛 21: 반사판 20: backlight unit 21: reflector

23: 광원 25: 확산판 23: light source 25: diffuser plate

27: 프리즘 시트 29: 확산시트27: prism sheet 29: diffusion sheet

본 발명은 액정표시장치의 백라이트 유닛에 관한 것으로서, 특히 시야각 특성을 향상시키는 확산시트가 구비된 백라이트 유닛에 관한 것이다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit of a liquid crystal display, and more particularly, to a backlight unit having a diffusion sheet for improving viewing angle characteristics.

통상적으로 액정표시장치(Liquid Crystal Display: 이하, "LCD"라 함)는 매 트릭스 형태로 배열되어진 다수의 액정셀들과 이들 액정셀들 각각에 공급될 비디오 신호를 변환하기 위한 다수의 제어용 스위치들로 구성된 액정패널에 의해 백라이트 유닛(backlight unit)에서 공급되는 광의 투과량이 조절되어 화면에 원하는 화상을 표시하게 된다. In general, a liquid crystal display (hereinafter referred to as "LCD") is a plurality of liquid crystal cells arranged in a matrix and a plurality of control switches for converting a video signal to be supplied to each of these liquid crystal cells. The amount of light transmitted from the backlight unit is controlled by the liquid crystal panel configured to display a desired image on the screen.

상기 액정패널은 자체 발광요소를 갖지 못하는 소자이므로 액정패널에 빛을 공급하기 위한 별도의 광원을 요구하게 된다. 이에 따라, 배면에는 백라이트 유닛이 마련되어 액정패널 전면을 향해 빛을 조사하고 이를 통해서 비로소 식별 가능한 휘도의 화상을 구현한다. Since the liquid crystal panel does not have a light emitting element, a separate light source for supplying light to the liquid crystal panel is required. Accordingly, a backlight unit is provided on the rear surface to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance.

한편, 백라이트 유닛에는 광원에서 발생된 광을 수직으로 집광 및 확산시키는 광학시트가 구비된다. 상세히 설명하면, 상기 백라이트 유닛의 광학시트에는 상부로 입사되는 빛을 액정패널의 화면에 집광시키는 프리즘 시트와, 프리즘 시트 상부에 형성되어 프리즘 시트에서 출사된 빛을 패널 전면으로 확산시키는 복수의 층으로 형성된 확산 시트가 구비된다. On the other hand, the backlight unit is provided with an optical sheet for condensing and diffusing the light generated from the light source vertically. In detail, the optical sheet of the backlight unit includes a prism sheet for condensing light incident on the screen of the liquid crystal panel and a plurality of layers formed on the prism sheet to diffuse the light emitted from the prism sheet to the entire surface of the panel. The formed diffusion sheet is provided.

이 확산 시트는 각층을 이루는 필름의 재질 및 두께, 각 층간의 거리 등의 조절을 통해 빛을 확산시킬 수 있도록 제조한다. The diffusion sheet is manufactured to diffuse light by controlling the material and thickness of the film constituting each layer, the distance between each layer.

그러나, 최근에는 액정표시장치의 시야각을 개선하기 위한 기술들이 개발되고 있는데, 종래의 확산시트는 액정패널의 화면에 대한 측면방향의 광이 취약하여 액정표시장치의 시야각특성을 오히려 저하시키게 한다. However, in recent years, techniques for improving the viewing angle of the liquid crystal display have been developed. In the conventional diffusion sheet, light in the lateral direction with respect to the screen of the liquid crystal panel is weak, thereby degrading the viewing angle characteristic of the liquid crystal display.

따라서, 액정패널의 화면에 대한 측면방향의 광을 개선하는 확산시트의 개발이 요구되고 있다. Accordingly, there is a demand for development of a diffusion sheet that improves light in the lateral direction with respect to the screen of the liquid crystal panel.

상술한 문제점을 해결하기 위한 본 발명의 목적은 액정표시장치의 시야각특성을 향상시킬 수 있도록 하는 확산시트를 구비한 백라이트유닛을 제공함에 있다. An object of the present invention for solving the above problems is to provide a backlight unit having a diffusion sheet to improve the viewing angle characteristics of the liquid crystal display device.

상술한 목적을 달성하기 위한 본 발명의 백라이트 유닛은 광을 발생시키는 광원과,광원 상부에 위치되며 광원으로부터의 광을 집광하는 프리즘 시트와, 상기 프리즘 시트 상에 위치되어 상기 프리즘 시트로부터의 광을 확산시키며, 베이스 필름과 베이스 필름의 상하부 각각에 서로 다른 헤이즈 특성의 범위를 갖는 상부 확산층과 하부 확산층으로 형성된 확산시트를 구비한다. The backlight unit of the present invention for achieving the above object is a light source for generating light, a prism sheet positioned above the light source and condensing light from the light source, and positioned on the prism sheet to receive light from the prism sheet Diffusion is provided, and each of the upper and lower portions of the base film and the base film is provided with a diffusion sheet formed of an upper diffusion layer and a lower diffusion layer having different ranges of haze characteristics.

상기 하부 확산층의 헤이즈 특성의 범위는 상기 상부 확산층의 헤이즈 특성의 범위보다 크게 형성된다. The range of the haze characteristic of the lower diffusion layer is greater than the range of the haze characteristic of the upper diffusion layer.

상기 하부 확산층의 헤이즈 특성의 범위는 45~90% 를 갖고, 상부 확산층의 헤이즈 특성의 범위는 10~40%를 갖는다. The range of haze characteristics of the lower diffusion layer is 45 to 90%, and the range of haze characteristics of the upper diffusion layer is 10 to 40%.

상기 상부 확산층 또는 하부 확산층은 바인더(binder)에 비즈(bead)를 섞어 상기 베이스 필름의 상부 또는 하부에 코팅하여 형성한다. The upper diffusion layer or the lower diffusion layer is formed by mixing beads on a binder and coating the upper or lower portion of the base film.

상기 베이스 필름은 얇고 투명성이 우수한 PET(PolyEthylene Terephthalate) 필름이다. The base film is a PET (PolyEthylene Terephthalate) film having excellent thinness and transparency.

상기 광원과 프리즘 시트 사이에는 빛을 확산시키는 확산판을 더 구비한다. A diffusion plate for diffusing light is further provided between the light source and the prism sheet.

상기와 같은 특징을 갖는 본 발명에 따른 백라이트 유닛에 대한 실시예를 첨부된 도면을 참조하여 보다 상세히 설명하면 다음과 같다. An embodiment of a backlight unit according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

도 1은 본 발명에 따른 백라이트 유닛의 구조를 도시한 분해 사시도로써, 이를 참조하여 설명하면 다음과 같다. 1 is an exploded perspective view illustrating a structure of a backlight unit according to the present invention.

도 1에 도시된 바와 같이, 백라이트 유닛(20)은 직하형의 백라이트 유닛으로써, 광을 발생시키는 광원(23)과, 광원(23) 하부와 측면에 배치되는 반사판(21)과, 상기 광원(23) 상부에 배치되어 입사된 빛을 확산시키는 확산판(25)과, 상기 확산판(25)의 상부에 위치하는 프리즘시트(27)와, 프리즘시트 상부에 형성되어 프리즘시트에서 출사된 빛을 액정패널 전면으로 확산시키는 3층으로 적층 형성된 확산 시트(29)가 구비된다. As shown in FIG. 1, the backlight unit 20 is a direct-type backlight unit, and includes a light source 23 for generating light, a reflector 21 disposed below and to the side of the light source 23, and the light source ( 23) a diffuser plate 25 disposed above and diffusing the incident light, a prism sheet 27 positioned above the diffuser plate 25, and light formed on the prism sheet and emitted from the prism sheet. A diffusion sheet 29 formed of three layers laminated to the entire liquid crystal panel is provided.

상기 백라이트 유닛(20) 상에는 도시되지 않은 액정패널이 위치하며, 액정패널은 백라이트 유닛으로부터 출사된 광의 투과율을 제어하여 화상을 구현한다.A liquid crystal panel (not shown) is positioned on the backlight unit 20, and the liquid crystal panel controls the transmittance of light emitted from the backlight unit to implement an image.

광원(23)은 냉음극 형광램프가 사용되며, 다수 개의 램프들로 소정간격을 두고 배치되어 있고, 광원(23)에서 발생된 광은 확산판(25)으로 입사된다. A cold cathode fluorescent lamp is used as the light source 23, and a plurality of lamps are disposed at predetermined intervals, and the light generated by the light source 23 is incident on the diffuser plate 25.

반사판(21)은 광원(23)으로부터의 광을 확산판(25)의 입사면 쪽으로 재반사시킴으로써 광손실을 줄이도록 한다. The reflecting plate 21 reduces light loss by reflecting light from the light source 23 back toward the incidence surface of the diffuser plate 25.

확산판(25)는 반사판(21) 또는 광원(23)으로 입사되는 빛을 액정패널 쪽으로 진행하도록 하고, 넓은 범위의 각도로 확산시킨다. The diffuser plate 25 allows the light incident on the reflector plate 21 or the light source 23 to propagate toward the liquid crystal panel and diffuses at a wide range of angles.

프리즘 시트(27)는 확산판(25)으로부터 입사되는 광을 액정패널의 화면에 대해 수직방향으로 집광시킨다. 한편, 프리즘 시트(27)의 하부 즉, 확산판(25)와 프리즘 시트(27) 사이에는 확산시트(미도시)가 더 구비될 수 있다. The prism sheet 27 collects light incident from the diffuser plate 25 in a direction perpendicular to the screen of the liquid crystal panel. Meanwhile, a diffusion sheet (not shown) may be further provided below the prism sheet 27, that is, between the diffusion plate 25 and the prism sheet 27.

상기 백라이트 유닛의 구성 중에서 프리즘 시트(19) 상부에 위치한 확산시 트(29)는 도 2에 도시된 바와 같이, 베이스 필름(12)과, 베이스 필름(12) 하부에 형성된 하부 확산층(14a)과, 베이스 필름(12) 상부에 형성된 상부 확산층(14b)으로 구성된다. As shown in FIG. 2, the diffusion sheet 29 disposed on the prism sheet 19 in the configuration of the backlight unit includes a base film 12, a lower diffusion layer 14a formed under the base film 12, And an upper diffusion layer 14b formed on the base film 12.

확산 시트(29)의 각 구성층들은 하나의 시트로 일체화되게끔 제작된다. Each component layer of the diffusion sheet 29 is manufactured to be integrated into one sheet.

베이스 필름(12)은 얇고 투명성이 우수한 PET(PolyEthylene Terephthalate) 필름과 같은 물질을 사용한다. The base film 12 uses a material such as a thin polyethylene film (PolyEthylene Terephthalate) film having excellent transparency.

하부 및 상부 확산층(14a, 14b)은 바인더(binder)에 비즈(bead)를 섞어 베이스 필름(12)의 상부면 및 하부면 각각에 코팅하여 형성한다. The lower and upper diffusion layers 14a and 14b are formed by mixing beads with a binder and coating the upper and lower surfaces of the base film 12, respectively.

이때, 하부 확산층(14a)의 헤이즈(Haze)특성 범위가 상부 확산층(14b)의 헤이즈(Haze) 특성 범위보다 크도록 형성한다. 구체적으로, 하부 확산층(14a)의 헤이즈(Haze) 특성은 45~ 90%의 범위를 갖고, 상부 확산층(14b)의 헤이즈(Haze) 특성은 10~ 40%의 범위를 갖도록 형성한다. At this time, the haze characteristic range of the lower diffusion layer 14a is formed to be larger than the haze characteristic range of the upper diffusion layer 14b. Specifically, the haze characteristic of the lower diffusion layer 14a is in the range of 45 to 90%, and the haze characteristic of the upper diffusion layer 14b is formed in the range of 10 to 40%.

따라서, 도 3a에 도시된 바와 같이, 하부 확산층(14a)의 상기 헤이즈 특성으로 인해, 프리즘 시트(27)에서 출사된 광이 산란(scattering)됨으로써, 액정패널의 전체 화면에 균일하게 분포되도록 하여 액정표시장치의 휘도 균일성(luminance uniformity)을 개선한다. Therefore, as shown in FIG. 3A, due to the haze characteristic of the lower diffusion layer 14a, the light emitted from the prism sheet 27 is scattered, so that the liquid crystal is uniformly distributed over the entire screen of the liquid crystal panel. Improve luminance uniformity of the display device.

또한, 도 3b에 도시된 바와 같이, 상부 확산층(14b)의 상기 헤이즈 특성으로 인해, 상부 확산층(14b)에서 출사된 광 중에서 액정패널에서 반사된 반사광을 상부 확산층(14b)에서 출사된 광들과 동일한 진행방향으로 정반사(specular reflection)시킴으로써, 액정패널의 화면에 대한 측면방향의 광량을 증가시키게 되어 액정표시 장치의 시야각특성을 개선한다. In addition, as shown in FIG. 3B, due to the haze characteristic of the upper diffusion layer 14b, the reflected light reflected from the liquid crystal panel among the light emitted from the upper diffusion layer 14b is the same as the light emitted from the upper diffusion layer 14b. By specular reflection in the advancing direction, the amount of light in the lateral direction with respect to the screen of the liquid crystal panel is increased to improve the viewing angle characteristic of the liquid crystal display device.

본 발명에 따른 확산시트가 구비된 액정표시장치를 통해 디스플레이되는 화상과, 종래의 확산시트가 채용된 액정표시장치를 통해 디스플레이되는 화상은 도 4b 및 도 4a에 각각 도시된다. An image displayed through a liquid crystal display device having a diffusion sheet according to the present invention and an image displayed through a liquid crystal display device employing a conventional diffusion sheet are shown in FIGS. 4B and 4A, respectively.

도 4a 및 도 4b를 참조하면, 도 4b의 상부에서 U45°, D45°, L45°, R45°에 도시된 화상은 도 4a의 U45°, D45°, L45°, R45°에 도시된 화상보다 휘도 균일성이 향상됨을 알 수 있고, 도 4b의 L45°, R45°에 도시된 화상은 도 4a의 L45°, R45°에 도시된 화상보다 시야각특성이 향상됨을 알 수 있다. 4A and 4B, the images shown at U45 °, D45 °, L45 °, and R45 ° at the top of FIG. 4B are luminance higher than those shown at U45 °, D45 °, L45 °, and R45 ° of FIG. 4A. It can be seen that the uniformity is improved, and the image shown at L45 ° and R45 ° in FIG. 4B has an improved viewing angle characteristic than the image shown at L45 ° and R45 ° in FIG. 4A.

이때, U45°는 액정표시장치의 상측 위치에서 45°기울어진 각도로 액정표시장치에 디스플레이되는 화상을 찍은 사진이고, D45°는 액정표시장치의 하측 위치에서 45°기울어진 각도로 액정표시장치에 디스플레이되는 화상을 찍은 사진이고, L45°는 액정표시장치의 좌측 위치에서 45°기울어진 각도로 액정표시장치에 디스플레이되는 화상을 찍은 사진이고, R45°는 액정표시장치의 우측 위치에서 45°기울어진 각도로 액정표시장치에 디스플레이되는 화상을 찍은 사진이다. At this time, U45 ° is a picture taken the image displayed on the liquid crystal display at an angle tilted 45 ° from the upper position of the liquid crystal display device, D45 ° is an angle of 45 ° tilted at the lower position of the liquid crystal display device to the liquid crystal display device Image taken is displayed, L45 ° is a picture taken on the liquid crystal display at an angle of inclination 45 ° from the left position of the liquid crystal display device, R45 ° is 45 ° tilted at the right position of the liquid crystal display device It is a picture of the image displayed on the liquid crystal display at an angle.

한편, 본 발명의 실시예에서는 직하형의 백라이트 유닛에 적용하고 있지만, 확산판 대신 도광판을 갖는 에지형의 백라이트 유닛에도 적용가능하다. On the other hand, although the embodiment of the present invention is applied to the backlight unit of the direct type, it is also applicable to the edge type backlight unit having a light guide plate instead of the diffuser plate.

이상에서 살펴본 바와 같이, 본 발명에 따른 45~ 90%의 헤이즈 특성을 갖는 하부 확산층과, 10~ 40%의 헤이즈 특성을 갖는 상부 확산층을 구비한 확산 시트를 구비함으로써, 액정패널의 화면에 대한 측면방향의 광량을 증가시키게 되어 액정표 시장치의 시야각특성을 개선하는 효과가 있다. As described above, by providing a diffusion sheet having a lower diffusion layer having a haze characteristic of 45 to 90% and an upper diffusion layer having a haze characteristic of 10 to 40% according to the present invention, the side of the screen of the liquid crystal panel The amount of light in the direction is increased, thereby improving the viewing angle characteristic of the liquid crystal display market value.

또한, 본 발명에 따라 45~ 90%의 헤이즈 특성을 갖는 하부 확산층과 10~ 40%의 헤이즈 특성을 갖는 상부 확산층을 구비한 확산 시트를 구비함으로써, 액정패널의 전체 화면에 균일하게 분포되도록 하여 액정표시장치의 휘도 균일성(luminance uniformity)을 개선하는 효과가 있다. In addition, according to the present invention by providing a diffusion sheet having a lower diffusion layer having a haze characteristic of 45 to 90% and an upper diffusion layer having a haze characteristic of 10 to 40%, the liquid crystal is uniformly distributed over the entire screen of the liquid crystal panel. There is an effect of improving the luminance uniformity of the display device.

Claims (6)

광을 발생시키는 광원과,A light source for generating light, 상기 광원 상부에 위치되며 광원으로부터의 광을 집광하는 프리즘 시트와,A prism sheet positioned above the light source and collecting light from the light source; 상기 프리즘 시트 상에 위치되어 상기 프리즘 시트로부터의 광을 확산시키며, 베이스 필름과 베이스 필름의 상하부 각각에 서로 다른 헤이즈 특성의 범위를 갖는 상부 확산층과 하부 확산층으로 형성된 확산시트를 구비하는 백라이트 유닛. And a diffusion sheet positioned on the prism sheet to diffuse the light from the prism sheet, and having a top diffusion layer and a bottom diffusion layer formed on each of upper and lower portions of the base film and the base film having different ranges of haze characteristics. 제1 항에 있어서, 상기 하부 확산층의 헤이즈 특성의 범위는 The method of claim 1, wherein the range of haze characteristics of the lower diffusion layer is 상기 상부 확산층의 헤이즈 특성의 범위보다 크게 형성되는 것을 특징으로 하는 백라이트 유닛.The backlight unit, characterized in that formed larger than the range of the haze characteristics of the upper diffusion layer. 제2 항에 있어서, 상기 하부 확산층의 헤이즈 특성의 범위는 45~90% 를 갖고, 상부 확산층의 헤이즈 특성의 범위는 10~40%를 갖는 것을 특징으로 하는 백라이트 유닛.The backlight unit of claim 2, wherein the haze characteristic of the lower diffusion layer is 45 to 90%, and the haze characteristic of the upper diffusion layer is 10 to 40%. 제1 항에 있어서, 상기 상부 확산층 또는 하부 확산층은 The method of claim 1, wherein the upper diffusion layer or lower diffusion layer 바인더(binder)에 비즈(bead)를 섞어 상기 베이스 필름의 상부 또는 하부에 코팅하여 형성하는 것을 특징으로 하는 백라이트 유닛. A backlight unit, characterized in that the bead (bead) mixed with a binder (binder) to form a coating on the upper or lower portion of the base film. 제1 항에 있어서, 상기 베이스 필름은 얇고 투명성이 우수한 PET(PolyEthylene Terephthalate) 필름인 것을 특징으로 하는 백라이트 유닛. The backlight unit of claim 1, wherein the base film is a thin, highly transparent polyethylene terephthalate (PET) film. 제1 항에 있어서, 상기 광원과 프리즘 시트 사이에는 The method of claim 1, wherein between the light source and the prism sheet 빛을 확산시키는 확산판을 더 구비하는 것을 특징으로 하는 백라이트 유닛. And a diffuser plate for diffusing light.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120018992A (en) * 2010-08-24 2012-03-06 엘지디스플레이 주식회사 Diffuser sheet and back light unit for liquid crystal display device having the same
WO2018008938A1 (en) * 2016-07-08 2018-01-11 주식회사 엘엠에스 Optical sheet, back light unit, and display device including same

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KR102250556B1 (en) * 2019-09-23 2021-05-12 주식회사 엘엠에스 Optical film for fingerprinting

Family Cites Families (4)

* Cited by examiner, † Cited by third party
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JP2977454B2 (en) * 1994-11-24 1999-11-15 積水化学工業株式会社 Image quality improvement film for liquid crystal display
WO2000038005A1 (en) * 1998-12-18 2000-06-29 Mitsubishi Rayon Co., Ltd. Transmission screen
KR100680127B1 (en) 2005-01-08 2007-02-07 도레이새한 주식회사 Light-diffusing sheet for back light unit of liquid crystal display
JP2007114409A (en) 2005-10-19 2007-05-10 Fujifilm Corp Optical sheet for display

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120018992A (en) * 2010-08-24 2012-03-06 엘지디스플레이 주식회사 Diffuser sheet and back light unit for liquid crystal display device having the same
WO2018008938A1 (en) * 2016-07-08 2018-01-11 주식회사 엘엠에스 Optical sheet, back light unit, and display device including same

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