KR20170035125A - 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.
A bottom cover including a bottom portion, a side wall extending from the bottom portion, at least one first fixing portion provided on the side wall, an outer wall surrounding the side wall of the bottom cover, a guide portion extending from the outer wall in the direction of the bottom cover, And a middle cabinet including a second fixing part protruding from a back surface area of the guide part and engaging with the first fixing part.

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.

On the other hand, in order to fix the bottom cover and the middle cabinet in the past, a screw fixing method using a screw or a fixing method using a tape or an adhesive was used.

However, in the case of the screw fixing system of the related art, the bottom cover and the middle cabinet need to be separately provided with screwing areas, and a further process of screw tightening is additionally required, resulting in additional costs, There is a need for this. Further, in the case of a fixing system using a conventional tape or an adhesive, there is a problem that a tape or an adhesive adhering area needs to be additionally provided, a step of attaching a tape or an adhesive is additionally required, and the processing power is weak.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems of the related art, and in particular, it provides a backlight unit in which a bottom cover and a middle cabinet are fixed without any additional configuration.

The present invention also provides a middle cabinet used for fabricating the backlight unit.

The bottom cover includes a bottom portion, a side wall extending from the bottom portion, at least one first fixing portion provided at the side wall, an outer wall surrounding the side wall of the bottom cover, And a middle cabinet including a guide portion extending in a cover direction and a second fixing portion protruded from a rear surface region of the guide portion and engaged with the first fixing portion.

Therefore, a separate structure is not required for fixing the bottom cover and the middle cabinet.

In the backlight unit according to another preferred embodiment of the present invention, the middle cabinet may further include an inner wall extending from the back surface of the guide portion toward the bottom portion and surrounding the inner surface of the side wall. Accordingly, during manufacture of the backlight unit, the middle cabinet may not flow into the bottom cover during the heat treatment process of the middle cabinet.

In the backlight unit according to another preferred embodiment of the present invention, the second fixing portion may be disposed in a region between the outer side wall and the inner side wall of the rear region of the guide portion. Therefore, the second fixing portion and the first fixing portion can be stably combined.

In the backlight unit according to another preferred embodiment of the present invention, the bottom cover may have a coupling groove on at least one of the opposite sides of the first fixing portion, which is a point where the first fixing portion and the side wall meet, have.

In the backlight unit according to still another preferred embodiment of the present invention, the first fixing portion protrudes from the side wall, and the second fixing portion may have a shape corresponding to the coupling groove.

In the backlight unit according to another preferred embodiment of the present invention, the first fixing portion may have a recessed shape, and the second fixing portion may have a shape corresponding to the coupling recess.

In addition, the present invention provides a liquid crystal display panel and a backlight unit as a solution to the above-mentioned problems, wherein the backlight unit includes a bottom portion, side walls extending from the bottom portion, And a second fixing portion protruded from a rear surface region of the guide portion and engaged with the first fixing portion, the bottom cover including an outer wall surrounding the side wall of the bottom cover, a guide portion extending from the outer wall in the direction of the bottom cover, A liquid crystal display device including a liquid crystal display device including a liquid crystal display device.

In the liquid crystal display device according to another preferred embodiment of the present invention, the middle cabinet may further include an inner wall extending from the back surface of the guide portion toward the bottom portion and surrounding the inner surface of the side wall.

In the liquid crystal display device according to still another preferred embodiment of the present invention, the second fixing portion may be disposed in a region between the outer wall and the inner wall of the rear region of the guide portion.

In the liquid crystal display device according to another preferred embodiment of the present invention, the bottom cover has a coupling groove on at least one of both sides of the first fixing part, which is a position where the first fixing part and the side wall meet, .

In the liquid crystal display device according to still another preferred embodiment of the present invention, the first fixing portion may protrude from the side wall, and the second fixing portion may have a shape corresponding to the coupling groove.

In the liquid crystal display device according to still another preferred embodiment of the present invention, the first fixing portion may have a recessed shape, and the second fixing portion may have a shape corresponding to the coupling recess.

In addition, the present invention provides, as means for solving the above-mentioned problems, an image forming apparatus including an outer wall, a guide portion extending inward from the outer wall, and an inner wall bent and extended from the guide portion, And a rear area between the inner wall and the inner wall protrudes from the inner wall of the middle cabinet.

In the middle cabinet according to another preferred embodiment of the present invention, the entire rear area between the outer side wall and the inner side wall of the rear side of the guide part may have a U shape, a V shape, Shape.

In the middle cabinet according to another preferred embodiment of the present invention, at least one protruding connection part may be provided in a part of the rear area between the outer wall and the inner wall of the rear area of the guide part.

In the middle cabinet according to another preferred embodiment of the present invention, the end of the connection part may be a U shape, a V shape, or a U shape.

Since the present invention does not require a separate structure for fixing the bottom cover and the middle cabinet, the process steps and the process time are reduced. In addition, since a region having a separate structure for fixing is not required in the past, the bottom cover itself can make the liquid crystal display device more visible, and the bezel of the liquid crystal display device is reduced, thereby improving the visibility.

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.
2 is a perspective view of a middle cabinet according to a first embodiment of the present invention.
3 is a perspective view of a middle cabinet according to a second embodiment of the present invention.
4 is a perspective view of a middle cabinet according to a third embodiment of the present invention.
5 is a perspective view of a middle cabinet and a bottom cover according to an embodiment of the present invention.
6 is a side view of a bottom cover according to a fourth embodiment of the present invention.
FIG. 7 is a cross-sectional view of the middle cabinet and the bottom cover AB according to the fourth embodiment of the present invention in FIG.
FIG. 8 is a sectional view of the middle cabinet and the bottom cover according to the fourth embodiment of the present invention in FIG. 5;
9 is a side view of a bottom cover according to a fifth embodiment of the present invention.
FIG. 10 is a cross-sectional view of a middle cabinet and a bottom cover according to a fifth embodiment of the present invention in FIG.
FIG. 11 is a sectional view of the middle cabinet and the bottom cover according to the fifth embodiment of the present invention in FIG. 5;
12 is a perspective view of a middle cabinet according to a sixth embodiment of the present invention.
13 is a perspective view of a middle cabinet according to a seventh embodiment of the present invention.
14 is a perspective view of a middle cabinet according to an eighth embodiment of the present invention.
15 is a side view of a bottom cover according to a ninth embodiment of the present invention.
16 is a perspective view of a middle cabinet and a bottom cover according to a ninth embodiment of the present invention.
FIG. 17 is a cross-sectional view of a middle cabinet and a bottom cover AB according to a ninth embodiment of the present invention in FIG.
FIG. 18 is a sectional view of a middle cabinet and a bottom cover according to a ninth embodiment of the present invention in FIG. 16;

Hereinafter, a backlight unit according to an embodiment of the present invention and a liquid crystal display including the same 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 middle cabinet 130, a bottom cover 150, a top cover 140, and an optical sheet 300 .

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 circuit board along at least one edge of the liquid crystal panel 110 to connect the side of the middle cabinet 130 or the bottom cover (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 a middle cabinet 130, an LED assembly 200 arranged along the longitudinal direction of at least one edge of the middle cabinet 130, a light guide plate 123, and an optical sheet 300 interposed therebetween, And a bottom cover 150, as shown in FIG.

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 125 may be positioned on the back surface of the light guide plate 123 and may reflect the light passing through the back surface of the light guide plate 123 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 middle cabinet 130 and the bottom cover 150. The top cover 140 covers the top surface of the liquid crystal panel 110 .

Here, the top cover 140 has a rectangular shape with a cross section bent in a "? &Quot; form so as to cover the upper surface of the liquid crystal panel 110 and is formed in the liquid crystal panel 110 by opening the front surface of the top cover 140 So as to display an image.

In addition, the bottom cover 150 is mounted on the liquid crystal panel 110 or the like, and is based on the assembly of the entire liquid crystal display device. In particular, the bottom cover 150 may include a first fixing part 151 that is fixed to the middle cabinet 130. In addition, the bottom cover 150 may be made of a metal material. When the bottom cover 150 is made of a plastic material, the bottom cover 150 may be made of a plastic material having a melting point higher than that of the middle cabinet 130.

In addition, the middle cabinet 130 may be configured to cover the side surfaces of the liquid crystal panel 110 and the like. In addition, the middle cabinet 130 may be exposed on a side surface of the LCD 100 to provide an appearance of the LCD 100. In addition, the material of the middle cabinet 130 may be a plastic material that can be melted by heat treatment or high frequency treatment.

2 is a perspective view of a middle cabinet 130 according to a first embodiment of the present invention.

Referring to FIG. 2, the first embodiment of the present invention is a middle cabinet 130 before the middle cabinet 130 is fixed to the bottom cover 150. The middle cabinet 130 according to the first embodiment includes an outer wall 130a, a guide portion 139 extending inward from the outer wall 130a, (130b). Specifically, the inner wall 130b may extend toward the upper surface of the bottom cover 150 from a rear surface area of the guide portion 139. FIG. Also, the rear surface area of the guide portion 139 may protrude. That is, the guide portion 139 may have a protruding portion 131 protruding downward in a rear region thereof. More specifically, the rear region between the outer side wall 130a and the inner side wall 130b of the rear region of the guide portion 139 protrudes downward, so that the rear region can have the protrusion 131. [ A protrusion 131 protruding in a 'V' shape may be formed on the entire rear region between the outer side wall 130a and the inner side wall 130b of the rear region of the guide portion 139. [

FIG. 3 is a perspective view of a middle cabinet according to a second embodiment of the present invention, and FIG. 4 is a perspective view of a middle cabinet according to a third embodiment of the present invention.

3 and 4, the second embodiment and the third embodiment of the present invention are the middle cabinets 130 before the middle cabinets 130 are fixed to the bottom cover 150. FIG. In the second and third embodiments of the present invention, the shape of the rear area of the guide part 139 in the first embodiment can be modified. That is, in the second embodiment, a U-shaped protrusion 132 (see FIG. 3) protruding downward is formed on the entire rear region between the outer side wall 130a and the inner side wall 130b, May be formed. The third embodiment differs from the first embodiment in that a protruding portion 133 protruding downwardly in a "ㅁ" shape is formed on the entire rear region between the outer side wall 130a and the inner side wall 130b of the rear region of the guide portion 139 May be formed. The projecting portions 131, 132, and 133 of the guide portion 139 are not limited to the illustrated shapes and may have different shapes as long as they can be protruded as a whole, in the rear area of the guide portion 139 of the middle cabinet 130. [ It is also possible.

5 is a perspective view of a middle cabinet 130 and a bottom cover 150 according to an embodiment of the present invention.

Referring to FIG. 5, the middle cabinet 130 and the bottom cover 150 according to the fourth and fifth embodiments of the present invention are fixed to each other. Specific fixed views of these will be described later.

6 is a side view of the bottom cover 150 according to the fourth embodiment of the present invention.

Referring to FIG. 6, the side wall 150c of the bottom cover 150 of the fourth embodiment may include a first fixing part 151 protruding upward from the side wall 150c. When a plurality of the first fixing portions 151 are formed, the plurality of first fixing portions 151 may be spaced apart from each other. Also, a first coupling groove 150a may be formed in the side wall 150c. The first fixing part 151 may be an embossed shape and the first engaging groove 150a may be formed on both sides of the first fixing part 151 in the upper surface of the side wall 150c. That is, the first coupling grooves 150a may be provided on both sides of the lower portion of the first fixing portion 151, respectively. More specifically, the first fixing part 151 may have a longer length in a direction parallel to the side wall 150c as it goes upward from the upper surface of the side wall 150c. A first coupling groove 150a may be formed on both sides of the lower portion of the first fixing portion 151, which is a position where the first fixing portion 151 and the side wall 150c meet.

On the other hand, the second fixing part 134, which will be described later, has a shape corresponding to the first coupling groove 150a and can be coupled with the first fixing part 151. [

FIG. 7 is a sectional view of the middle cabinet 130 and the bottom cover 150 according to the fourth embodiment of the present invention, and FIG. 8 is a cross-sectional view of the middle cabinet 130 according to the fourth embodiment of the present invention, And the bottom cover 150, respectively.

7 and 8, the bottom cover 150 of the present invention includes a bottom portion 150b, side walls 150c extending from the bottom portion 150b, and at least one 1 fixing portion 151 of the first embodiment. The middle cabinet 130 of the present invention can be coupled to the bottom cover 150 and includes an outer wall 130a surrounding the side wall 150c of the bottom cover 150 and a guide portion 139, A second fixing portion 134 disposed on the back surface of the first fixing portion 139, and an inner side wall 130b.

The outer side wall 130a may be disposed on the outer side of the side wall 150c and the guide portion 139 may extend from the outer side wall 130a to the inner side of the bottom cover 150. [ And the second fixing part 134 may protrude from the rear surface of the guide part 139 and may be fixed to the first fixing part 151 and the inner side wall 130b may be fixed to the guide part 139, May extend from the portion 139 toward the bottom portion 150b and be disposed inside the side wall 150c.

The second fixing portion 134 of the middle cabinet 130 may be interposed in the first fixing groove 150a of the first fixing portion 151. [

A method of interposing the second fixing portion 134 in the first coupling groove 150a of the first fixing portion 151 will be described. First, the middle cabinets 130 of the first to third embodiments may be used. The protrusions 131, 132 and 133 of the guide portion 139 of the middle cabinet 130 are brought into contact with the upper portion of the first fixing portion 151 of the bottom cover 150. The contact areas are then subjected to heat treatment or high frequency treatment so that a part of the projecting parts 131, 132 and 133 of the rear surface of the guide part 139 of the middle cabinet 130 are melted, And intervenes there. That is, the protrusions 131, 132, and 133 of the guide portion 139 of the middle cabinet 130 are partially melted so that the second fixing portions (not shown) that are interposed in the first coupling groove 150a of the first fixing portion 151 134). However, the present invention is not limited to the above-described method. Alternatively, the second fixing portion 134 may be interposed in the first coupling groove 150a of the first fixing portion 151.

Therefore, a separate fastening structure is not required to fix the bottom cover 150 and the middle cabinet 130. [

9 is a side view of a bottom cover according to a fifth embodiment of the present invention.

Referring to FIG. 9, the side wall 150c of the bottom cover 150 of the fifth embodiment may include a first fixing portion 152 and a first coupling groove 150a. The first fixing part 152 may be an embossed shape and the first engaging groove 150a may be provided on one side of the lower part of the first fixing part 152. [ The first fixing part 152 may protrude upward from the upper surface of the side wall 150c and may be provided on one side of the first fixing part 152 and on the upper side of the first fixing part 152 From the upper surface of the first fixing portion 152 to the point where the first fixing portion 152 and the side wall 150c meet from the first fixing portion 152, May be shorter than the distance to the point where the first fixing part (152) meets the side wall (150c). That is, both side surfaces of the first fixing part 152 may have inclined surfaces. Both side surfaces of the first fixing part 152 may be inclined in the same direction to have inclined surfaces.

FIG. 10 is a sectional view of the middle cabinet 130 and the bottom cover 150 according to the fifth embodiment of the present invention, and FIG. 11 is a cross-sectional view of the middle cabinet 130 according to the fifth embodiment of the present invention, And the bottom cover 150, respectively.

10 and 11, the bottom cover 150 of the present invention includes a bottom portion 150b, side walls 150c extending upwardly from the bottom portion 150b, And may include one or more protruding first fixing portions 151. The middle cabinet 130 of the present invention can be engaged with the bottom cover 150 and includes an outer side wall 130a surrounding the side wall 150c of the bottom cover 150 and a guide portion 150c extending from the outer side wall 130a. And a second fixing part 134 and an inner side wall 130b disposed in a rear area of the guide part 139. [

The outer side wall 130a may be disposed on the outer side of the side wall 150c and the guide portion 139 may extend from the outer side wall 130a to the inner side of the bottom cover 150. [ And the second fixing part 134 extending downward from the rear surface of the guide part 139 can be fixed to the first fixing part 152 and the inner side wall 130b can be fixed to the first fixing part 152. [ And may extend from the guide portion 139 toward the bottom portion 150b and be disposed inside the side wall 150c.

The second securing portion 134 of the middle cabinet 130 may be interposed in the first engaging groove 150a of the first securing portion 152.

The method in which the second fixing portion 134 is interposed in the first coupling groove 150a of the first fixing portion 152 is the same as that of the fourth embodiment. That is, first, the middle cabinets 130 of the first to third embodiments can be used. The projections 131, 132 and 133 of the guide portion 139 of the middle cabinet 130 are brought into contact with the upper portion of the first fixing portion 152 of the bottom cover 150. The projected portions 131, 132, and 133 of the middle cabinet 130 are partially melted and flowed into the first coupling grooves 151a through heat treatment or high-frequency processing. That is, the protrusions 131, 132, and 133 of the middle cabinet 130 are partially melted and become the second fixing parts 134 that are interposed in the first coupling groove 150a of the first fixing part 152. However, the present invention is not limited to the above-described method. Alternatively, the second fixing portion 134 may be interposed in the first fixing groove 150a of the first fixing portion 152.

Therefore, a separate fastening structure is not required to fix the bottom cover 150 and the middle cabinet 130. [

12 is a perspective view of a middle cabinet according to a sixth embodiment of the present invention.

Referring to FIG. 12, the sixth embodiment of the present invention is a middle cabinet 130 before the middle cabinet 130 is fixed to the bottom cover 150. According to the sixth embodiment, the middle cabinet 130 includes an outer wall 130a, a guide portion 130c extending inward from the outer wall 130a, and a guide portion 130c extending from the guide portion 130c, (130b). Specifically, the inner wall 130b may extend toward the upper surface of the bottom cover 150 from a rear area of the guide 130c. Also, a portion of the rear surface region of the guide portion 130c may have one or more protruding connection portions 135. That is, the connection portion 135 may have at least one shape, and may have a shape protruding downward in a part of the rear region of the guide portion 130c. More specifically, the connection part 135 may protrude downward in a part of the rear surface area between the outer side wall 130a and the inner side wall 130b of the rear area of the guide part 130c. In addition, the end of the connection part 135 may have a V shape.

FIG. 13 is a perspective view of a middle cabinet according to a seventh embodiment of the present invention, and FIG. 14 is a perspective view of a middle cabinet according to an eighth embodiment of the present invention.

13 and 14, the seventh embodiment and the eighth embodiment of the present invention are the middle cabinets 130 before the middle cabinets 130 are fixed to the bottom cover 150. FIG.

In the seventh embodiment and the eighth embodiment of the present invention, the shape of the connection portion 135 may be modified in the sixth embodiment. That is, in the seventh embodiment, the end of the connection part 136 may be in a U-shape. In addition, in the eighth embodiment, the end of the connection part 137 may be in the shape of a letter. Accordingly, the connection portion of the middle cabinet 130 is not limited to the shape of the connection portions 135, 136, and 137, but may be other shapes.

15 is a side view of a bottom cover 150 according to a ninth embodiment of the present invention.

Referring to FIG. 15, the side wall 150c of the bottom cover 150 of the ninth embodiment may have a first fixing portion 153 and a second coupling groove 150d. In addition, the first fixing part 153 may be engraved, and the first fixing part 153 may have at least one second joining recess 150d. That is, the second engaging groove 150d may be provided on both sides of the lower portion of the first fixing portion 153. [ In addition, the second engagement groove 150d may have a feature that the lateral width of the bottom cover 150 is constant toward the bottom of the bottom cover 150, and the lateral width of the bottom of the bottom cover 150 is widened at a predetermined depth.

16 is a perspective view of a middle cabinet 130 and a bottom cover 150 according to a ninth embodiment of the present invention.

Referring to FIG. 16, the middle cabinet 130 and the bottom cover 150 according to the ninth embodiment of the present invention are fixed to each other.

16 is a cross-sectional view of the middle cabinet 130 and the bottom cover 150 according to the ninth embodiment of the present invention, and FIG. 18 is a cross-sectional view of the middle cabinet 130 according to the ninth embodiment of the present invention, And the bottom cover 150, respectively.

17 and 18, the bottom cover 150 of the present invention includes a bottom portion 150b, a side wall 150c extending from the bottom portion 150b, And a < / RTI > The middle cabinet 130 of the present invention can be coupled to the bottom cover 150 and includes an outer wall 130a and a guide portion 130c surrounding the side wall 150c of the bottom cover 150, A second fixing portion 138 disposed on the back surface of the first and second fixing portions 130a and 130c, and an inner side wall 130b.

The second fixing portion 138 of the middle cabinet 130 may be embossed and may be interposed in the second coupling recess 150d of the first fixing portion 153. [ Therefore, compared with the fourth and fifth embodiments in which the side wall 150c of the bottom cover 150 includes the first fixing portion 151 protruding upward from the side wall 150c, in the case of the ninth embodiment And the first fixing portion 153 are engraved, it is possible to form a backlight unit thickness smaller than the backlight unit thicknesses of the fourth and fifth embodiments.

A method of interposing the second fixing portion 138 in the first coupling groove 150d of the first fixing portion 153 will be described. First, the middle cabinets 130 of the sixth to eighth embodiments may be used. The connecting portions 135, 136, and 137 of the middle cabinet 130 are inserted into the first fixing portions 153 of the bottom cover 150. Thereafter, the inserted region is subjected to heat treatment or high-frequency treatment to partially melt the connection portions 135, 136, and 137 of the middle cabinet 130 and flow into the second coupling groove 151d. That is, the connecting portions 135, 136, 137 of the middle cabinet 130 are partially melted and become the second fixing portions 138 interposed in the second coupling grooves 150d of the first fixing portion 153. However, the present invention is not limited thereto. Alternatively, the second fixing portion 138 may be interposed in the second engaging groove 150d of the first fixing portion 153. [

Accordingly, since the present invention does not require a separate structure for fixing the bottom cover 150 and the middle cabinet 130, the process steps and the process time are reduced. In addition, since the area where a separate structure for fixing is conventionally required is not needed, the bottom cover 150 itself can make the appearance of the liquid crystal display device, and the bezel of the liquid crystal display device is reduced, .

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 middle cabinet
131, 132, 133 contact
134, 138,
135, 136, 137,
140 Top cover
150 bottom cover
151, 152, 153,
200 LED assembly
210 light source
220 PCB
300 optical sheet

Claims (16)

A bottom cover including a bottom portion, a side wall extending from the bottom portion, and at least one first fixing portion provided on the side wall;
A middle cabinet including an outer wall surrounding the side wall of the bottom cover, a guide portion extending from the outer wall in the direction of the bottom cover, and a second fixing portion protruded from a rear region of the guide portion and engaged with the first fixing portion Backlight unit. The method according to claim 1,
In the middle cabinet,
And an inner side wall extending from the back surface of the guide portion toward the bottom portion and surrounding the inner surface of the side wall. 3. The method of claim 2,
And the second fixing portion is disposed in a region between the outer side wall and the inner side wall of the rear region of the guide portion. The method according to claim 1,
Wherein the bottom cover has a coupling groove on at least one of both sides of the first fixing portion, which is a point where the first fixing portion and the side wall meet. 5. The method of claim 4,
Wherein the first fixing portion protrudes from the side wall,
And the second fixing portion has a shape corresponding to the coupling groove. 6. The method of claim 5,
Wherein the first fixing portion is engraved,
And the second fixing portion has a shape corresponding to the coupling groove. A liquid crystal display panel; And
A backlight unit,
The backlight unit includes:
A bottom cover including a bottom portion, a side wall extending from the bottom portion and at least one first fixing portion protruded from the side wall, an outer wall surrounding the side wall of the bottom cover, a guide portion extending from the outer wall in the bottom cover direction, And a second fixing part protruded from a rear surface area of the guide part and engaged with the first fixing part. 8. The method of claim 7,
In the middle cabinet,
And an inner side wall extending from the back surface of the guide portion toward the bottom portion and surrounding the inner surface of the side wall. 9. The method of claim 8,
And the second fixing portion is disposed in a region between the outer side wall and the inner side wall of the rear region of the guide portion. 8. The method of claim 7,
Wherein the bottom cover has a coupling groove on at least one of both sides of the first fixing part, which is a position where the first fixing part and the side wall meet. 11. The method of claim 10,
Wherein the first fixing part protrudes from the side wall, and the second fixing part has a shape corresponding to the coupling groove. 11. The method of claim 10,
Wherein the first fixing portion is engraved,
And the second fixing portion has a shape corresponding to the coupling groove. An outer wall, a guide portion extending inward from the outer wall, and an inner wall extending from the guide portion so as to bend,
And a rear region between the outer wall and the inner wall of the rear region of the guide portion protrudes. 14. The method of claim 13,
U 'shape, a' V 'shape or a' K 'shape on the entire rear region between the outer side wall and the inner side wall of the rear region of the guide portion. 14. The method of claim 13,
Wherein at least a portion of the back surface region of the guide portion has at least one protruding connection portion in a portion of the back surface region between the outer side wall and the inner side wall. 16. The method of claim 15,
Wherein an end of the connecting portion is a U-shaped, a V-shaped, or a U-shaped.

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