KR20170035063A - Backlight unit and liquid crystal display device having the same - Google Patents

Abstract

The present invention relates to a backlight unit and a liquid crystal display including the same.
The present invention can provide a backlight unit including a light guide plate, a bottom cover that houses the light guide plate, and a first frame unit that is disposed between a back surface of the light guide plate and an upper surface of the bottom cover and is coupled to the bottom cover.

Description

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

The present invention relates to a backlight unit and a liquid crystal display including the same.

BACKGROUND 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. Thereby forming an image on the panel. The liquid crystal display device using such a principle has been gradually widened due to features such as light weight, thinness, and low power consumption driving. In accordance with this trend, the liquid crystal display device is used in office automation equipment, audio / video equipment, and the like.

In such a liquid crystal display device, a light transmission amount is adjusted according to a signal applied to a plurality of control switches arranged in a matrix form to display a desired image on a screen.

In recent years, liquid crystal display devices have been widely applied not only to computer monitors, televisions, display devices for navigation systems for vehicles, and portable display devices such as notebook computers and cellular phones.

In general liquid crystal display devices, a voltage is applied to a specific molecular array of a liquid crystal to convert it into another molecular array, and changes in optical properties such as birefringence, spinelability, dichroism and light scattering characteristics of a liquid crystal cell emitting light by such molecular arrangement And is a light-receiving type display device for displaying information by using modulation of light by a liquid crystal cell. Since such a liquid crystal display device is a light receiving type device, it includes a backlight unit for providing light to express an image, and the backlight unit is divided into a direct type and an edge type according to the arrangement of the light sources .

The direct-type backlight unit is a system in which a plurality of light sources are arranged directly under the liquid crystal display panel at regular intervals and directly irradiated directly under the liquid crystal display panel. The edge-type backlight unit includes a light guide plate for converting light emitted from the light source into surface light Thereby emitting light to the liquid crystal display panel. BACKGROUND ART A backlight unit of a liquid crystal display device includes optical sheets composed of a diffusion plate, a diffusion sheet and a prism sheet in order to improve optical characteristics of light emitted from a light source, for example, luminance uniformity and front luminance.

Meanwhile, the conventional bottom cover is deformed due to the weight of the internal structure of the liquid crystal display device. Therefore, in order to prevent the bottom cover from being deformed and to ensure rigidity, the bottom cover may be formed in a shape to form a concavity or convexity, or the frame may be fastened to the outer surface of the bottom cover by screws or the like.

However, in the case of the conventional technique, forming the concavo-convex shape of the bottom cover does not secure sufficient rigidity, and when the frame is screwed to the outer surface of the bottom cover, the number of assembled holes increases, There arises a problem of an increase in thickness and weight increase.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and in particular, it is intended to prevent deformation of the bottom cover, secure rigidity of the bottom cover, and further reduce the thickness of the liquid crystal display device.

The backlight unit may include a light guide plate, a bottom cover that houses the light guide plate, and a first frame portion that is disposed between a back surface of the light guide plate and an upper surface of the bottom cover and is coupled to the bottom cover . Therefore, the rigidity of the bottom cover can be reinforced by the first frame portion.

According to another embodiment of the present invention, there is provided a backlight unit, wherein an upper surface of the bottom cover is parallel to a back surface of the light guide plate. Therefore, the thickness of the bottom cover can be reduced.

In the backlight unit according to still another preferred embodiment of the present invention, the first frame portion includes a plurality of integral frame fingers constituting at least one opening, the upper surface of the bottom cover includes first and second regions, The first region facing the frame fence, and the second region corresponding to the opening portion. Therefore, it is possible to secure a region where the bottom cover can be pressed or screwed by the opening.

In another aspect of the present invention, there is provided a backlight unit, wherein the frame body of the first frame unit is radial or lattice-shaped. Therefore, the opening of the first frame portion can be ensured and the rigidity of the bottom cover can be reinforced.

In still another aspect of the present invention, there is provided a backlight unit, wherein the second area is a foaming shape. Therefore, the rigidity of the bottom cover can be further reinforced.

In the backlight unit according to another preferred embodiment of the present invention, the backlight unit further includes a second frame portion and a joining member disposed on a lower surface of the bottom cover, and the second region of the bottom cover includes a first And the second frame portion includes a second engaging portion corresponding to the first engaging portion, and the bottom cover and the second frame portion are engaged with the first engaging portion and the second engaging portion, The backlight unit can be fixed.

In addition, the present invention provides a liquid crystal display panel and a backlight unit as a solution to the above-described problems, wherein the backlight unit includes a light guide plate, a bottom cover for accommodating the light guide plate, and an upper surface between the back surface of the light guide plate and the bottom cover And a first frame portion coupled to the bottom cover.

In another preferred embodiment of the liquid crystal display according to the present invention, the top surface of the bottom cover is parallel to the back surface of the light guide plate.

In the liquid crystal display according to another preferred embodiment of the present invention, the first frame portion includes a plurality of integral frame fingers constituting at least one opening portion, the upper surface of the bottom cover includes first and second regions , The first region faces the first frame portion, and the second region corresponds to the opening portion.

According to the present invention, since the rigidity of the bottom cover is increased, deformation of the backlight unit due to external or internal external force is reduced, and the bottom cover does not form irregularities for reinforcing rigidity, So that the thickness of the liquid crystal display device can be reduced. The bottom cover is not required to have additional configuration on the outer surface of the bottom cover for reinforcing rigidity. Further, the second area of the bottom cover can be subjected to a pressing operation or a screwing operation.

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.
2 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention.
3 is a plan view of the bottom cover and the first frame according to the first embodiment of the present invention.
4 is a plan view of the bottom cover and the first frame according to the second embodiment of the present invention.
5 is a plan view of the bottom cover and the first frame according to the third embodiment of the present invention.
6 is a plan view of the bottom cover and the first frame part according to the fourth embodiment of the present invention
7 is a cross-sectional view of a liquid crystal display device according to a fifth embodiment of the present invention.
8 is a cross-sectional view of a liquid crystal display device according to a sixth embodiment of the present invention.
9 is a cross-sectional view of a liquid crystal display device according to a seventh embodiment of the present invention.

Hereinafter, an optical sheet according to an embodiment of the present invention and a liquid crystal display device including the optical sheet will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of an apparatus may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification. The dimensions and relative sizes of the layers and regions in the figures may be exaggerated for clarity of illustration.

It will be understood that when an element or layer is referred to as being another element or "on" or "on ", it includes both intervening layers or other elements in the middle, do. On the other hand, when a device is referred to as "directly on" or "directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below," "lower," "above," "upper," and the like, And may be used to easily describe the correlation with other elements or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions.

The terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprise "and / or" comprising ", as used in the specification, means that the presence of stated elements, Or additions.

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.

1, a liquid crystal display 100 includes a liquid crystal panel 110, a backlight unit 120, a support main 130, a bottom cover 150, a top cover 140, a first frame unit 400 ).

The liquid crystal panel 110 includes a color filter array substrate 112 and a TFT array substrate 114 and a liquid crystal layer (not shown) interposed therebetween. The color filter array substrate 112 and the TFT array substrate And a polarizing plate (not shown) is attached to the outer surface of the light guide plate 114

In this liquid crystal panel 110, liquid crystal cells constituting pixel units are arranged in a matrix form, and liquid crystal cells adjust image transmittance according to image signal information transmitted from a driver driving circuit to form an image.

Specifically, on the inner surface of the TFT array substrate 114, a plurality of gate lines and data lines intersect to define pixels, and thin film transistors (TFTs) are provided at each of the intersections, One-to-one correspondence with the transparent pixel electrodes.

The inner surface of the color filter array substrate 112 is provided with color filters of red (R), green (G), and blue (B) A data line, and a black matrix covering a non-display element such as a thin film transistor. In addition, a transparent common electrode covering these elements is provided.

A gate and a data printed circuit board 117 are connected to each other via a connection member 116 such as a flexible printed circuit board along at least one edge of the liquid crystal panel 110 to support the side of the support main 130, (150).

The driving signal of the liquid crystal panel 110 provided from the gate and the data printed circuit board 117 on one side of the liquid crystal panel 110 is supplied to a plurality of gate lines and a plurality of data lines of the liquid crystal panel 110 And the liquid crystal panel 110 is driven. When the liquid crystal panel 110 controls the voltage of the data signal applied to the pixel electrode in the state where the voltage is applied to the common electrode, the liquid crystal layer rotates by dielectric anisotropy according to the electric field between the common electrode and the pixel electrode, An image is displayed by transmitting or blocking light for each pixel region.

Although not clearly shown in the drawing, an alignment film for determining the initial alignment direction of the liquid crystal is interposed at the boundary between the color filter array substrate 112 and the TFT array substrate 114 and the liquid crystal layer of the liquid crystal panel 110 A seal pattern is formed along the edges of the color filter array substrate 112 and the TFT array substrate 114 to prevent leakage of the liquid crystal layer filled therebetween.

A backlight unit 120 for supplying light is provided on a back surface of the liquid crystal panel 110 so that a difference in transmittance represented by the liquid crystal panel 110 is externally expressed.

The backlight unit 120 includes an LED assembly 200 arranged along the longitudinal direction of at least one edge of the support main body 130, a light guide plate 123 and an optical sheet 300 interposed therebetween, a bottom cover 150, And a first frame part 400 disposed between a back surface of the light guide plate 123 and an upper surface of the bottom cover 150. [

The LED assembly 200 is a light source of the backlight unit 120 and is disposed at one side of the light guide plate 123 so as to face the light incident surface of the light guide plate 123. The LED assembly 200 includes a plurality of LEDs 210, And a PCB 220 on which a plurality of LEDs 210 are mounted at a predetermined interval.

Light emitted from the plurality of LEDs 210 is provided to the liquid crystal panel 110 via the light guide plate 123.

As the material of the light guide plate 123, PMMA (Polymethylmethacrylate), which has high strength and is not easily deformed or broken and has a high transmittance, may be used. Here, the light guide plate 123 may be a wedge having a lower surface inclined and a flat upper surface, or a plate type having a lower surface and an upper surface all in parallel. In addition, the thickness of the light guide plate 123 may be relatively larger.

The light guide plate 123 may include a condensing pattern (not shown) on its upper surface.

The outgoing angle of light emitted to the upper surface of the light guide plate 123 can be adjusted according to the density of the light condensing pattern.

The optical sheet 300 may be composed of one optical sheet or a plurality of optical sheets. The optical sheet 300 may be formed by bonding a plurality of optical sheets together. The optical sheet 300 may include a diffusion sheet, a prism sheet, and a protective sheet. In some cases, it may be provided with two diffusion sheets and two prism sheets. At this time, the diffusion sheet may include a base plate and a bead coating layer formed on the base plate.

The diffusion sheet 300 diffuses light from the light guide plate 123 and supplies the light to the liquid crystal panel 110. Two or three sheets of the diffusion sheet may be used in a superimposed manner. In addition, the prism sheet may have a triangular columnar prism with a predetermined arrangement on the upper surface. The prism sheet may function to condense light diffused in the diffusion sheet in a direction perpendicular to the plane of the upper liquid crystal panel 110. Two prism sheets may be used, and the micro prisms formed on each prism sheet form a predetermined angle. Accordingly, the light passing through the prism sheet proceeds almost vertically and provides a uniform luminance distribution. The topmost protective sheet protects the prism sheet, which is susceptible to scratches.

The reflection plate (not shown) may be positioned on the back surface of the light guide plate 123 as needed, and the light passing through the back surface of the light guide plate 123 may be reflected toward the liquid crystal panel 110 to improve the brightness of light.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130 and the bottom cover 150. The top cover 140 is disposed on the top edge of the liquid crystal panel 110, So as to cover the side surface.

Here, the top cover 140 has a rectangular frame shape bent in a "? &Quot; shape so as to cover the top and side edges of the liquid crystal panel 110, As shown in Fig.

In addition, the bottom cover 150, on which the liquid crystal panel 110 and the backlight unit 120 are mounted and is a basis for assembling the entire structure of the liquid crystal display device, includes a bottom portion and side walls whose edges are vertically bent.

In this case, the top cover 140 may be referred to as a case top or a top case, and the support main 130 may be referred to as a guide panel, a main support, or a mold frame, and the bottom cover 150 may be referred to as a bottom cover.

The first frame part 400 may be disposed between the back surface of the light guide plate 123 and the top surface of the bottom cover 150 and may be coupled to the bottom cover 150. The first frame part 400 can reinforce the rigidity of the bottom cover 150. The first frame part 400 may be made of metal or non-metal. When the first frame part 400 is used as a metal, the degree of reinforcement of the bottom cover 150 is greater than when the first frame part 400 is used as a base metal. On the other hand, when the first frame unit 400 is used as a base metal, the weight of the backlight unit 120 is reduced compared with the case where the first frame unit 400 is made of metal. Accordingly, the material of the first frame part 400 can be a material suitable for the situation.

At this time, the method of joining the first frame part 400 and the bottom cover 150 can be performed by disposing a double-sided tape or applying an adhesive on the upper surface of the first frame part 400 and the back surface of the bottom cover 150. When either the first frame part 400 or the bottom cover 150 is made of plastic, the first frame part 400 and the bottom cover 150 may be joined to each other by a thermal or high- The first frame part 400 and the bottom cover 150 may be fusion-bonded to each other.

In addition, the shape of the first frame portion 400 may be any machinable shape.

That is, the first frame portion 400 includes a plurality of integral frame fingers 410 forming at least one opening portion 410, and the upper surface of the bottom cover 150 includes first and second regions, The first region may face the frame fence 410 and the second region may correspond to the opening 420. In this case, the second area of the bottom cover 150 can be subjected to a pressing operation or a screwing operation.

FIG. 2 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 3 is a plan view of a bottom cover and a first frame part according to the first embodiment of the present invention.

2, the first frame part 400 is disposed between the back surface of the light guide plate 123 and the top surface of the bottom cover 150 and is coupled with the bottom cover 150. Further, a reflection plate (not shown) may be further disposed between the light guide plate 123 and the first frame unit 400.

In the first embodiment of the present invention, the top surface of the bottom cover 150 may be parallel to the back surface of the light guide plate 123. In this case, since the rigidity of the bottom cover 150 is sufficiently reinforced by the first frame part 400, the bottom cover 150 does not form irregularities or the like for reinforcing rigidity, and the thickness becomes thin. Accordingly, the thickness of the backlight unit 120 is reduced, and the thickness of the liquid crystal display device 100 can be reduced.

3 is a plan view of the bottom cover 150 and the first frame part 400 according to the first embodiment of the present invention.

Referring to FIG. 3, the frame fence 410 of the first frame part 400 according to the first embodiment may have a lattice shape. That is, the frame fence 410 includes a first frame fence 410a surrounding an edge of a bottom portion of the bottom cover 150, and a second frame fence 410b interposed between the first frame flesh 410a and the first frame fence 410a, And second and third frame fingers 410b and 410c that form the opening 420. [

FIG. 4 is a plan view of the bottom cover 150 and the first frame part 400 according to the second embodiment of the present invention. FIG. 5 is a plan view of the bottom cover 150 and the first frame part 400 according to the third embodiment of the present invention. 6 is a plan view of the bottom cover 150 and the first frame part 400 according to the fourth embodiment of the present invention

Referring to FIG. 4, the frame fence 410 of the first frame part 400 according to the second embodiment may be a radial shape. That is, the frame fence 410 includes a first frame fence 410a surrounding an edge of a bottom portion of the bottom cover 150, and a second frame fence 410b interposed between the first frame flesh 410a and the first frame fence 410a, The second and third frame weights 410b and 410c forming the opening 420 and the fourth frame weights 410d connecting the two opposing edges of the first frame weights 410a, And a fifth frame fence 410e connecting the corners.

That is, since the frame fence 410 is radial or lattice-shaped, the bottom cover 150 may not be separated from the bottom cover 150 due to heat or other factors, 150 can be fixed.

Referring to FIG. 5, the frame fence 410 of the first frame unit 400 according to the third embodiment is formed by combining the radial shape and the lattice shape. That is, the frame fence 410 includes a first frame fence 410a surrounding an edge of a bottom portion of the bottom cover 150, and a second frame fence 410b interposed between the first frame flesh 410a and the first frame fence 410a, The second and third frame fingers 410b and 410c forming the opening 420 and the opening 420 formed by the second and third frame fingers 410b and 410c may have a rectangular shape, And a sixth frame fence 410f connecting two opposing edges of at least one opening 420 among the plurality of opening portions 420. [

6, the frame fence 410 of the first frame unit 400 according to the fourth embodiment is in a lattice shape, and the frame fence 410 is disposed in a part of the upper surface of the bottom cover 150 . That is, the frame fence 410 of the first frame unit 400 can be disposed only in the area where the bottom cover 150 needs to be reinforced. That is, the first frame part 400 may surround half the bottom of the bottom cover 150.

Therefore, the shape of the frame weights 410 may be one of shapes for reinforcing the rigidity of the bottom cover 150 while securing the opening of the first frame unit 400.

FIG. 7 is a cross-sectional view of a liquid crystal display device according to a fifth embodiment of the present invention, and FIG. 8 is a cross-sectional view of a liquid crystal display device according to the sixth embodiment of the present invention.

Referring to FIGS. 7 and 8, the second area of the bottom cover 150 corresponding to the opening of the frame part 400 may be a foaming shape.

That is, in the fifth embodiment, the inner forming portion 151 having a foaming shape can be formed inside the bottom cover 150 using a pressing operation or the like in the second area of the bottom cover 150 . In the sixth embodiment, the outer forming portion 152 having a foaming shape outside the bottom cover 150 can be formed using a pressing operation or the like in the second area of the bottom cover 150 .

When forming the outer and inner forming portions 151 and 152 of the foaming shape, the internal or external external force applied to the bottom cover 150 is dispersed, so that the rigidity of the bottom cover 150 can be reinforced. In the case of the fifth embodiment, the foaming shape 151 is formed inward, and the thickness of the backlight unit 120 is still reduced. In the sixth embodiment, the foaming shape 152 is formed outside, so that the thickness of the backlight unit 120 can be increased. However, the second area of the bottom cover 150 is narrowed to form a foaming shape The sixth embodiment can be used.

9 is a cross-sectional view of a liquid crystal display device according to a seventh embodiment of the present invention.

9, in the case of the seventh embodiment, the backlight unit 120 may further include a second frame part 500 and a coupling member 600 disposed on the bottom surface of the bottom cover 150 . The second area of the bottom cover 150 may include a first engaging part 153 and the second frame part 500 may include a first engaging part 153 and a second engaging part 153, The bottom cover 150 and the second frame part 500 may have the first and second coupling parts 153 and the coupling part 600 coupled to the first coupling part 153 and the second coupling part 501, .

The material of the second frame part 500 may be metal or non-metal. In addition, the shape of the second frame part 500 may be a foaming shape. That is, the shape of the second frame part 500 may be a shape absorbing an external force applied to the bottom cover 150.

The coupling member 600 may be a fastening screw, but is not limited thereto.

In the seventh embodiment, it is not possible to form a foaming shape on the bottom cover 150 as in the fifth and sixth embodiments, or to reinforce the bottom cover 150 more effectively than the other embodiments Lt; / RTI > However, in this case, the thickness of the liquid crystal display device 120 may increase.

Accordingly, since the rigidity of the bottom cover 150 is increased by the present invention, the deformation of the backlight unit 120 due to the external or internal external force is reduced, and the bottom cover 150 does not form irregularities for reinforcing rigidity Since the thickness of the backlight unit 120 is thinner, the thickness of the liquid crystal display device 100 can be reduced. The bottom cover 150 is not required to have an additional structure on the outer surface of the bottom cover 150 for reinforcing rigidity, so that the number of fastening holes and the fitting tolerance according to the additional configuration does not occur. Further, the second area of the bottom cover 150 can be subjected to a pressing operation or a screwing operation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and 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 liquid crystal display
110 liquid crystal panel
112 color filter array substrate
114 TFT array substrate
116 connecting member
117 printed circuit board
120 Backlight Unit
123 light guide plate
130 Support Main
131 coupling portion
140 Top cover
150 bottom cover
151, 152 forming configuration
153 first coupling portion
200 LED assembly
210 light source
220 PCB
300 optical sheet
400 first frame portion
500 Second frame part
501 second coupling portion
600 coupling member

Claims (9)

A light guide plate;
A bottom cover for accommodating the light guide plate; And
And a first frame part disposed between a back surface of the light guide plate and an upper surface of the bottom cover and coupled with the bottom cover. The method according to claim 1,
Wherein an upper surface of the bottom cover is parallel to a back surface of the light guide plate. The method according to claim 1,
The first frame part includes a plurality of integral frame firings constituting at least one opening,
The top surface of the bottom cover includes first and second regions,
The first region facing the frame fence, and the second region corresponding to the opening. The method of claim 3,
Wherein the frame body of the first frame part is radial or lattice-shaped. The method of claim 3,
And the second region is a foaming shape. The method of claim 3,
The backlight unit includes:
A second frame portion disposed on a lower surface of the bottom cover; And
And a coupling member,
Wherein the second region of the bottom cover has a first engagement portion,
The second frame portion includes a second coupling portion corresponding to the first coupling portion,
Wherein the bottom cover and the second frame part are fixedly coupled to the first and second coupling parts. A liquid crystal display panel; And
A backlight unit,
The backlight unit includes a light guide plate, a bottom cover for housing the light guide plate,
And a first frame portion disposed between a back surface of the light guide plate and an upper surface of the bottom cover and coupled to the bottom cover. 8. The method of claim 7,
And the upper surface of the bottom cover is parallel to the back surface of the light guide plate. 8. The method of claim 7,
The first frame part includes a plurality of integral frame firings constituting at least one opening,
The top surface of the bottom cover includes first and second regions,
Wherein the first region faces the first frame portion, and the second region corresponds to the opening portion.

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