KR20150031935A - Backlight unit and liquid crystal display having the same - Google Patents

Backlight unit and liquid crystal display having the same Download PDF

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Publication number
KR20150031935A
KR20150031935A KR20130111787A KR20130111787A KR20150031935A KR 20150031935 A KR20150031935 A KR 20150031935A KR 20130111787 A KR20130111787 A KR 20130111787A KR 20130111787 A KR20130111787 A KR 20130111787A KR 20150031935 A KR20150031935 A KR 20150031935A
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KR
South Korea
Prior art keywords
light
guide plate
region
light guide
circuit board
Prior art date
Application number
KR20130111787A
Other languages
Korean (ko)
Inventor
송범석
Original Assignee
엘지디스플레이 주식회사
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Publication date
Application filed by 엘지디스플레이 주식회사 filed Critical 엘지디스플레이 주식회사
Priority to KR20130111787A priority Critical patent/KR20150031935A/en
Publication of KR20150031935A publication Critical patent/KR20150031935A/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F21K9/61—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using light guides
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0028—Light guide, e.g. taper
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
    • G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
    • G02B6/0048—Tapered light guide, e.g. wedge-shaped light guide with stepwise taper
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0051—Diffusing sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0086—Positioning aspects
    • G02B6/0088—Positioning aspects of the light guide or other optical sheets in the package
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0086—Positioning aspects
    • G02B6/0091—Positioning aspects of the light source relative to the light guide
    • G—PHYSICS
    • G02—OPTICS
    • 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
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Abstract

The present invention relates to a backlight unit capable of preventing light leakage and a liquid crystal display having the same, and the backlight unit includes a light source unit having a printed circuit board and a plurality of light sources mounted on the printed circuit board to supply light; A first region located in a light-incident portion receiving light emitted from the plurality of light sources and having a first thickness; and a second region having a first region and a second region, A light guide plate including a second region that is stepped to have a thickness of 2; And a second step part which is coupled with the light source part and the light guide plate to support the light source part and the light guide plate and has a first step part spaced from a top surface of one side edge by a predetermined distance and a second step part formed to be spaced apart from the first step part by a predetermined distance Wherein one end of the printed circuit board is coupled to one end of the main frame and the other end of the printed circuit board is coupled to an upper surface and a side surface of the first area of the light guide plate.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY HAVING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit and a liquid crystal display device having the same, and more particularly, to a backlight unit that can prevent a light leakage and a liquid crystal display including the same.

2. Description of the Related Art In general, a liquid crystal display (LCD) displays a desired image by adjusting the light transmittance of liquid crystal cells arranged in a matrix according to image signal information. The display panel displays the image.

The liquid crystal display device using such a principle has a tendency of widening its application range due to features such as light weight, thinness and low power consumption driving. According to this trend, the liquid crystal display device is used for a television (TV), a computer monitor, an indoor / outdoor advertisement display device, a display portion of an office automation device, a display portion of an audio / video device, a display portion of a home appliance, Recently, recently, a liquid crystal display device has been widely used as a display device of a vehicle navigator system, a notebook computer, a netbook, a personal digital assistant (PDA), a mobile phone, and portable display devices such as a smartphone. A transmissive liquid crystal display device that occupies most of the liquid crystal display device controls an electric field applied to the liquid crystal layer to modulate light incident from the backlight unit to display an image.

Since most of the liquid crystal display devices described above are non-emissive type display devices that display images by adjusting the amount of light received from the outside, a backlight unit including a separate light source for irradiating light to the liquid crystal display panel need.

The backlight unit is roughly divided into a direct type and an edge type. The direct-type backlight unit has a structure in which a plurality of light sources are arranged in a line on a lower surface of a diffuser plate so that light can proceed directly to a front surface of a liquid crystal display device. On the other hand, the edge type backlight unit has a structure in which a light source is disposed so as to face the side face of the light guide plate and a plurality of optical films are disposed between the liquid crystal display panel and the light guide plate. In the edge type backlight unit, the light source irradiates light to one side of the light guide plate, and the light guide plate converts the light or glow emitted from the light source into planar light, thereby advancing the light to the front side of the liquid crystal display device.

Conventionally, CCFL (Cold Cathode Fluorescent Lamp), HCFL (Hot Cathode Fluorescent Lamp), EEFL (External Electrode Fluorescent Lamp) and the like have been used as the light source of the backlight unit. Recently, however, Emitting diode (hereinafter referred to as "LED") has been spotlighted due to its advantages such as high brightness and excellent contrast ratio and long lifetime.

1 is a side sectional view showing the structure of an edge type backlight unit having a conventional flat light guide plate using an LED as a light source. 1, an edge type backlight comprises a light source portion including an LED housing 2 for receiving an LED 1 and a light source portion disposed adjacent to the LED 1 so that light from the LED 1 is incident on the side, A light guide plate 3 disposed on the lower surface of the light guide plate 3 for reflecting the light traveling toward the lower portion of the light guide plate 3 toward the upper side of the light guide plate 4 Optical films 5 arranged on the upper surface of the light guide plate 3 for improving the uniformity of the light emitted from the light guide plate 3 and the light source housing 2 are fixed and the light guide plate 3 and the reflective sheet 4 And a bottom cover 6 supporting the bottom cover 6.

2. Description of the Related Art In recent years, the shape of a light guide plate of a backlight unit has gradually changed from a flat type to a wedge type in accordance with a demand for thinning of a liquid crystal display device. 2 is a cross-sectional view illustrating a conventional backlight unit having a wedge-shaped light guide plate.

As shown in Fig. 2, the wedge-shaped light guide plate 13 for attaining thinning has a thinner thickness in the active area A / A, but the light-incident part in which the light enters is maintained as it is. Therefore, a difference in thickness between the light entrance portion of the light guide plate 13 and the active area A / A becomes large, so that a light leakage phenomenon occurs in which light leaks along the inclined surface 13a of the light guide plate 13.

Accordingly, it is an object of the present invention to provide a backlight unit and a liquid crystal display including the same, which can prevent light leakage even if a wedge-shaped light guide plate is used.

According to an aspect of the present invention, there is provided a backlight unit comprising: a light source unit including a printed circuit board and a plurality of light sources mounted on the printed circuit board to supply light; A first region located in a light-incident portion receiving light emitted from the plurality of light sources and having a first thickness; and a second region having a first region and a second region, A light guide plate including a second region that is stepped to have a thickness of 2; And a second step part which is coupled with the light source part and the light guide plate to support the light source part and the light guide plate and has a first step part spaced from a top surface of one side edge by a predetermined distance and a second step part formed to be spaced apart from the first step part by a predetermined distance Wherein one end of the printed circuit board is coupled to one end of the main frame and the other end of the printed circuit board is coupled to an upper surface and a side surface of the first area of the light guide plate.

In the above configuration, the printed circuit board includes a horizontal part and a bent part bent perpendicularly from one end of the horizontal part, one end of the horizontal part being fixed to the first stepped part of the main frame, Is fixed to the upper surface of the first region of the light guide plate, and the bent portion is fixed to the inner surface of the first region of the light guide plate.

In addition, the horizontal portion and the bent portion of the printed circuit board are fixed to the main frame and the light guide plate by a fixing member.

The fixing member may include a horizontal portion; A plurality of horizontal extensions disposed at regular intervals along one edge of the horizontal portion and extending toward the opposite side of the one edge; And a plurality of vertical extensions extending in a vertical direction from the plurality of horizontal extensions.

In addition, a horizontal portion of the fixing member and one surface of the plurality of horizontal extending portions are fixed to a horizontal surface of the printed circuit board, one surface of the plurality of vertical extending portions is fixed to the bent portion of the printed circuit board, Wherein one end of the other surface of the horizontal portion of the member is fixed to a first step of the mold frame, a plurality of horizontal extensions of the fixing member are fixed to an upper surface of the first region of the light guide plate, Are fixed to the side surface of the first region of the light guide plate.

Further, the backlight unit according to the present invention may further include a plurality of optical sheets disposed on the second region of the light guide plate.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a backlight unit having any one of the above features; And a liquid crystal display panel disposed above the backlight unit and displaying an image.

The liquid crystal display device includes a backlight unit and a liquid crystal display panel. The backlight unit and the liquid crystal display panel are fixed to each other by a frame region in which the backlight unit and the liquid crystal display panel are overlapped with each other. Tape. ≪ / RTI >

According to the backlight unit and the liquid crystal display device having the same according to the present invention, since the bent portion of the printed circuit board of the light source portion covers the upper surface and the side surface of the first region formed in the light-incoming portion of the light guide plate, . Accordingly, it is possible to prevent light leakage caused by the conventional wedge type light guide plate.

1 is a cross-sectional view of a conventional backlight unit having a planar light guide plate,
FIG. 2 is a cross-sectional view of a conventional backlight unit having a wedge-
3 is an exploded perspective view showing a backlight unit according to an embodiment of the present invention,
4 is an exploded perspective view showing the light source unit and the fixing member shown in Fig. 3,
5 is a cross-sectional view taken along the line I-I 'of FIG. 3, taken along a portion having a light source,
FIG. 6 is a cross-sectional view taken along the line I-I 'of FIG. 3, taken along a portion where there is no light source,
7 is an exploded perspective view illustrating a liquid crystal display device having a backlight unit according to an embodiment of the present invention,
8 is a cross-sectional view taken along line I-I 'of FIG. 7, taken along a portion where a light source is present,
9 is a cross-sectional view taken along the line I-I 'of FIG. 7, taken along a portion where there is no light source.

Hereinafter, a backlight unit according to a preferred embodiment of the present invention and a liquid crystal display device having the same will be described in detail with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

First, referring to Figs. 3 to 6, a backlight unit according to an embodiment of the present invention will be described. FIG. 3 is an exploded perspective view showing a backlight unit according to an embodiment of the present invention, FIG. 4 is an exploded perspective view showing the light source unit and fixing member shown in FIG. 3, and FIG. 6 is a cross-sectional view taken along the line I-I 'of Fig. 3, taken along a portion where there is no light source. Fig. 6 is a cross-sectional view taken along the line I-

3, a backlight unit 100 according to an embodiment of the present invention includes a light source unit 110, a light guide plate 120 that converts light emitted from the light source unit 110 into plane light and outputs the light to the front surface, A plurality of optical films 140 disposed on the light guide plate 120, a light guide plate 120, and a light guide plate 120. The light guide plate 120 includes a reflective sheet 130 disposed below the light guide plate 120, A mold frame 150 for supporting the reflective sheet 130 and a fixing member 150 for fixing one side of the light source unit 110 to the mold frame 150 and fixing the other side of the light source unit 110 to the light- (160).

3 to 6, the light source unit 110 is of an edge type so as to face the light incident surface of the light guide plate 120. The light source unit 110 includes a printed circuit board 110a and a plurality of light sources (for example, light emitting diodes (LEDs) 110b) mounted on the printed circuit board 110a. The printed circuit board 110a includes a horizontal portion 110a1 and a bent portion 110a2 extending from one end of the horizontal portion 110a1 and extending substantially perpendicular thereto. The plurality of light sources 110b are mounted on the horizontal portion 110a1 of the printed circuit board 110a at regular intervals and blinked by a circuit mounted on the printed circuit board 110a.

In the embodiment of the present invention, the light source unit 110 is configured as a side view type, and the side surface of the light source 110b mounted on the printed circuit board 110a faces the light incoming surface of the light guide plate 120 .

The light guide plate 120 includes a first region 120a and a second region 120b. The first region 120a is formed in the light-incident portion and has a first thickness. The second region 120b is formed corresponding to the active region A / A to convert the light incident through the first region 120a into planar light and emit the light. The second region 120b also includes a second region 120b that extends from the first region 120a and is stepped to have a second thickness that is less than the first thickness of the first region 120a.

The first region 120a of the light guide plate 120 is positioned to face the light source 110b so that the light emitted from the light source 110b enters the first region 120a of the light guide plate 120 through the light entrance surface. The second region 120b of the light guide plate 120 emits the light incident from the light source 110b to the first region of the light guide plate 120 toward the optical sheet 140 disposed on the upper portion of the light guide plate 120. [ For this purpose, a diffusion pattern (not shown) may be formed on the bottom surface of the light guide plate 120 to scatter light directed to the lower portion of the light guide plate 120 and direct the light toward the upper side. The light guide plate 120 converts the light incident from the light source 110b into uniform plane light and outputs the light to the optical sheet 140 disposed on the upper side of the light guide plate 120. [

The light guide plate 120 may be formed of a material having good refractive index and transmittance such as polymethylenemethacrylate (PMA), polycarbonate (PC), polyethylene (PE), cycloolefin resin (COP) And the like are used, but they are not limited to these materials.

The reflective sheet 130 is disposed under the light guide plate 120 and is incident through the light incident portion of the light guide plate 120 to reflect light emitted to the lower portion of the light guide plate 120 toward the light guide plate 120, The reflection amount of the entire incident light is adjusted so that the entire emission surface has a uniform luminance distribution.

The optical sheet 140 is for diffusing and condensing the light incident from the light guide plate 120 and includes a diffusion sheet 140a, a prism sheet 140b and a protective sheet 140c. The diffusion sheet 140a is composed of a base plate and a bead coating layer formed on the base plate, and diffuses the light from the light source 140b and supplies the diffusion to the upper portion. The prism sheet 140b is formed such that prismatic prisms are arranged on the upper surface of the prism sheet 140b. The prism sheet 140b condenses light diffused from the diffusion sheet 140a in a direction perpendicular to the plane of the liquid crystal display panel LCP. The protective sheet 140c is formed on the prism sheet 140b to protect the prism sheet 140b which is vulnerable to scratches.

The mold frame 150 supports the light source unit 110, the light guide plate 120, and the reflection plate 130. The mold frame 150 includes a first step portion 150a in which one end of the horizontal portion 110a1 of the printed circuit board 110a of the light source portion 110 is disposed and a second step portion 150b in which the light source 110b of the light source portion 110 is accommodated And a second step portion 150b for supporting the light guide plate 120 and the reflection plate 130. [

The fixing member 160 includes a horizontal portion 160a, a plurality of horizontal extending portions 160b disposed at regular intervals along one edge of the horizontal portion 160a and extending toward the opposite side of the one edge, And a plurality of vertical extensions 160c extending in a substantially vertical direction from the horizontal extensions 160b. A plurality of openings 160d are formed by the horizontal and vertical extensions 160b and 160c. The fixing member 160 may be a double-sided tape or an adhesive.

A structure in which the printed circuit board 110a of the light source unit 110 is coupled to the mold frame 150 and the light guide plate 120 by the fixing member 160 will be described.

One surface of the horizontal portion 160a of the fixing member 160 is adhered to the horizontal portion 110a1 of the printed circuit board 110a of the light source portion 110 in the region where the light source 110b is disposed, Is adhered to the first step portion 150a of the mold frame 150 (see Figs. 4 and 5). The one end of the horizontal portion 110a1 of the printed circuit board 110a of the light source unit 110 is bonded to the first step portion 150a of the mold frame 150. [

On the other hand, in a region where the light source 110b is not disposed, one surface of the horizontal portion 160a and the horizontal extension portion 160b of the fixing member 160 is connected to the horizontal portion 110a1 of the printed circuit board 110a of the light source portion 110 And the other surface is adhered to the first step portion 150a of the mold frame 150 and the upper surface and side surfaces of the first region 120a of the light guide plate 120. [ One surface of the vertical extension 160c of the fixing member 160 is adhered to the bent portion 110a2 of the printed circuit board 110a of the light source unit 110 in the region where the light source 110b is not disposed, Are bonded to the upper surface and the side surface of the first region 120a of the light guide plate 120 (see Figs. 4 and 6). The bent portion 110a2 of the printed circuit board 110a of the light source unit 110 is attached to the upper surface and the side surface of the first region 120a of the light guide plate 120. [

Next, a liquid crystal display device having a backlight unit according to an embodiment of the present invention will be described with reference to FIGS. 7 to 9. FIG. FIG. 7 is an exploded perspective view illustrating a liquid crystal display device having a backlight unit according to an embodiment of the present invention, FIG. 8 is a cross-sectional view taken along line I-I 'of FIG. 7, , And FIG. 9 is a cross-sectional view taken along the line I-I 'of FIG. 7, taken along a portion where there is no light source.

7 to 9, a liquid crystal display device 200 having a backlight unit according to an embodiment of the present invention includes the backlight unit 100, the light shielding tape 200, and the liquid crystal display panel 200 described with reference to FIGS. 3 to 6, And a display panel 300.

Since the backlight unit 100 has been fully described with reference to Figs. 3 to 6, the following description is omitted in order to avoid duplication of description.

The light shielding tape 200 serves to fix the backlight unit 200 and the liquid crystal display panel 300 by applying an adhesive on both sides. The light shielding tape 200 is entirely black, and functions to prevent light emitted from the backlight unit from leaking to the outside.

The liquid crystal display panel 300 includes a thin film transistor substrate 300a disposed on the optical sheets 140 and having a thin film transistor formed thereon, a black matrix formed in a lattice pattern opposite to the thin film transistor substrate 300a, And a color filter substrate 300b including color filters formed between the color filters 300a and 300b. The thin film transistor substrate 300a and the color filter substrate 300b are sealed by a sealant, and a liquid crystal layer (not shown) is formed between these two substrates.

One end of the thin film transistor substrate 300a is formed longer than one end of the color filter substrate 300b and a driving driver 320 in the form of a chip may be formed at that position. A flexible printed circuit board (FPCB) 310 connected to a driving driver is provided at one end of the thin film transistor substrate 300a. The flexible circuit board 310 may be bent 180 degrees and disposed on the lower surface of the main frame.

According to the above-described backlight unit and the liquid crystal display device having the same, since the bent portion of the printed circuit board of the light source portion covers the upper surface and the side surface of the first region formed in the light-incoming portion of the light guide plate, The light is blocked without being leaked to the outside. Accordingly, it is possible to prevent light leakage caused by the conventional wedge type light guide plate.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100: backlight unit 110: light source unit
110a: printed circuit board 110a1: horizontal part
110a2: bent portion 110b: light source
120: light guide plate 120a: first region
120b: second region 130: reflective sheet
140: optical sheet 150: mold frame
150a: first stage jaw part 150b: second stage jaw part

Claims (8)

A light source unit having a printed circuit board and a plurality of light sources mounted on the printed circuit board to supply light;
A first region located in a light-incident portion receiving light emitted from the plurality of light sources and having a first thickness; and a second region having a first region and a second region, A light guide plate including a second region that is stepped to have a thickness of 2; And
A first step portion which is coupled with the light source portion and the light guide plate to support the light source portion and the light guide plate and is spaced apart from a top surface of one side edge and a second step portion which is spaced apart from the first step portion by a predetermined distance, Comprising a mainframe,
Wherein one end of the printed circuit board is coupled to one end of the main frame and the other end of the printed circuit board is coupled to an upper surface and a side surface of the first region of the light guide plate.
The method according to claim 1,
Wherein the printed circuit board includes a horizontal portion and a bent portion bent perpendicularly from one end of the horizontal portion,
The other end of the horizontal portion is fixed to the upper surface of the first region of the light guide plate, and the bent portion is fixed to the inner surface of the first region of the light guide plate And a backlight unit.
3. The method of claim 2,
Wherein the horizontal portion and the bent portion of the printed circuit board are fixed to the main frame and the light guide plate by a fixing member.
The method of claim 3,
The fixing member
Horizontal part;
A plurality of horizontal extensions disposed at regular intervals along one edge of the horizontal portion and extending toward the opposite side of the one edge; And
And a plurality of vertical extensions extending vertically from the plurality of horizontal extensions.
5. The method of claim 4,
Wherein one side of the horizontal part of the fixing member and one side of the plurality of horizontal extending parts are fixed to a horizontal plane of the printed circuit board and one side of the plurality of vertical extending parts is fixed to a bent part of the printed circuit board,
One end of the other surface of the horizontal portion of the fixing member is fixed to the first step portion of the mold frame, the plurality of horizontal extending portions of the fixing member are fixed to the upper surface of the first region of the light guide plate, And the vertical extending portions are fixed to the side surface of the first region of the light guide plate.
6. The method of claim 5,
Further comprising a plurality of optical sheets disposed on an upper portion of the second region of the light guide plate.
A backlight unit according to any one of claims 1 to 6; And
And a liquid crystal display panel disposed above the backlight unit and displaying an image.
8. The method of claim 7,
And a light shielding tape for fixing the backlight unit and the liquid crystal display panel by arranging a frame region overlapping the backlight unit and the liquid crystal display panel and preventing light emitted from the backlight unit from leaking to the outside And the liquid crystal display device.


KR20130111787A 2013-09-17 2013-09-17 Backlight unit and liquid crystal display having the same KR20150031935A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109254450A (en) * 2017-07-13 2019-01-22 Lg 电子株式会社 Display device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109254450A (en) * 2017-07-13 2019-01-22 Lg 电子株式会社 Display device

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