KR20070084946A - Backlight assembly and liquid crystal display having the same - Google Patents

Abstract

A backlight assembly and a liquid crystal display including the same are provided to easily and stably couple a guide groove of a diffusion plate and/or a guide protrusion of an optical sheet with the mold frame having a guide part formed at a bottom mold frame, thereby preventing deterioration of optical characteristics of an exit light due to movement of the optical sheet. A bottom mold frame(260) has guide parts including a connecting plane at one side and two separately protruded walls(262a,262b) protruded from the connecting plane for defining an optical sheet guide space. An optical sheet has guide protrusions inserted into the optical sheet guide space of the guide part, and the guide parts are arranged on a bottom of the bottom mold frame.

Description

Backlight assembly and liquid crystal display including the same

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

2 is a perspective view of a mold frame of the backlight assembly according to an embodiment of the present invention.

3 is a perspective view of a guide part of the mold frame of FIG. 2.

4 is a perspective view of a diffusion plate of a backlight assembly according to an embodiment of the present invention.

5 is a plan view illustrating the diffusion plate of FIG. 4 coupled to the guide unit of FIG. 3.

6 and 7 are cross-sectional views taken along lines VI-VI 'and VII-VII' of FIG. 5, respectively.

8 is a perspective view of an optical sheet of a backlight assembly according to an embodiment of the present invention.

9 is a plan view of the diffusion plate of FIG. 4 and the optical sheet of FIG. 8 coupled to the guide unit of FIG. 3.

10 and 11 are cross-sectional views taken along the line VII'- 'and XI-XI' of FIG. 9, respectively.

12 is a partial cross-sectional view of a backlight assembly according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

110: first display panel 120: second display panel

130: printed circuit board 140: gate drive IC

150: data drive IC 200: backlight assembly

210: light source 220: reflective sheet

230: diffuser 240: optical sheet

250: bottom chassis 260: bottom mold frame

270: upper mold frame 300: top chassis

500: liquid crystal display

The present invention relates to a backlight assembly and a liquid crystal display device including the same, and more particularly, to a backlight assembly in which an optical sheet is easily guided and stably fastened to a mold frame, and a liquid crystal display device including the same.

A liquid crystal display (LCD) is a device that displays an image by injecting liquid crystal between two glass plates and applying power to the upper and lower glass plate electrodes to change the liquid crystal molecular array in each pixel. Unlike a cathode ray tube (CRT), a plasma display panel (PDP), and the like, a display by a liquid crystal display is not light-emitting because it is non-luminous in itself. To compensate for these disadvantages, a backlight assembly that is uniformly irradiated on the information display surface is mounted for the purpose of enabling use in a dark place.

The backlight assembly used in the conventional liquid crystal display device is largely divided into two types. The first is an edge type backlight assembly that provides light from the side of the liquid crystal display and the second type is a direct backlight assembly that provides light directly from the back of the liquid crystal display.

In the case of the edge type backlight assembly, a light guide plate is provided to allow the light emitted from the light source to be irradiated upward, and an optical sheet is provided on the light guide plate to adjust optical characteristics of the light passing through the light guide plate. In the case of the direct type backlight assembly, a diffuser plate is provided to reduce bright lines of light emitted from the light source, and an optical sheet is provided to adjust optical characteristics of light passing through the diffuser plate.

Such a light guide plate or a diffuser plate and an optical sheet are accommodated in a mold frame so as to be aligned in the backlight assembly. In this case, the mold frame guides the optical sheet and the like, and has a cylindrical emboss to prevent the flow of the optical sheet and the like, and correspondingly, the optical sheet or the like is provided with fixing holes. By inserting the embossing into the fixing hole, the optical sheet is fastened to the mold frame.

However, if there is no significant difference between the diameter of the fixing hole and the diameter of the embossing, it is difficult to insert the embossing correctly. If the diameter of the fixing hole is sufficiently larger than the diameter of the embossing, the optical sheet and the mold frame are stably coupled such as the emboss is pulled out from the fixing hole. can not do. Furthermore, the fastening between the optical sheet and the mold frame becomes more unstable due to external impact during the movement of the backlight assembly, expansion of the optical sheet, etc. due to heat. When these are separated and the optical sheet flows, the optical characteristics of the light emitted from the backlight assembly may be deteriorated.

An object of the present invention is to provide a backlight assembly in which an optical sheet is easily guided to a mold frame and is stably fastened.

Another object of the present invention is to provide a liquid crystal display device including the backlight assembly as described above.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a bottom mold including a guide part including at least one connection surface and two guide walls spaced apart from each other to protrude therefrom to define an optical sheet guide space. And an optical sheet disposed on the bottom mold frame and having a guide protrusion inserted into the optical sheet guide space of the guide part, wherein the guide part is disposed on a bottom surface of the bottom mold frame. .

According to another aspect of the present invention, there is provided a liquid crystal display device for displaying an image, and disposed below the liquid crystal display panel to provide light to the liquid crystal display panel, and at least one side. A bottom mold frame having a connecting surface and a guide portion comprising two protruding walls spaced apart from each other to protrude therefrom and defining an optical sheet guide space, and the optical sheet guide space disposed on the bottom mold frame, An optical sheet having a guide protrusion inserted into the guide sheet, wherein the guide portion includes a backlight assembly disposed on a bottom surface of the bottom mold frame.

Specific details of other embodiments are included in the detailed description and drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It may be used to easily describe the correlation of a device or components with other devices or components. Spatially relative terms are to be understood as including terms in different directions of the device in use or operation in addition to the directions shown in the figures. Like reference numerals refer to like elements throughout.

Hereinafter, a backlight assembly and a liquid crystal display will be described in embodiments of the present invention with reference to the accompanying drawings.

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

Referring to FIG. 1, the liquid crystal display device 500 is disposed under the liquid crystal display panels 110 and 120 and the liquid crystal display panels 110 and 120 that display an image to emit light to the liquid crystal display panels 110 and 120. It provides a backlight assembly 200.

The liquid crystal display panels 110 and 120 are disposed on the backlight assembly 200 and display an image by using light supplied from the backlight assembly 200. The liquid crystal display panel includes a first display panel 110, a second display panel 120, and a liquid crystal layer (not shown) interposed therebetween.

The first display panel 110 has a transparent insulating substrate such as glass as a base substrate, and a thin film transistor, a thin film transistor, and a pixel electrode driven by the switching element are arranged in a matrix form thereon. The thin film transistor is connected to the plurality of gate lines and the plurality of data lines.

The second display panel 120 is disposed to face the first display panel, and color filter patterns are arranged under the transparent insulating substrate such as glass as a base substrate. In addition, the second display panel may include a common electrode that generates an electric field in the liquid crystal layer together with the pixel electrode of the first display panel. Meanwhile, the color filter and / or the common electrode may be provided on the first display panel 110.

The gate driver IC 140 is disposed on one side of the first display panel 110, and the data driver IC 150 is disposed on the other side of the first display panel 110. The gate driver IC 140 is connected to the first display panel 110 by the gate TCP 141 and provides a gate signal to the gate line of the first display panel 110. The data driver IC 150 is connected to the first display panel 110 by the data TCP 151 and provides a data signal to a data line of the first display panel 110. On the other hand, the other side of the data TCP 151 is attached to the printed circuit board 130 on which a timing controller or the like is mounted.

The backlight assembly 200 that provides light to the liquid crystal display panels 110 and 120 is disposed below the liquid crystal display panels 110 and 120 as described above. The backlight assembly 200 includes a light source 210, a reflective sheet 220, a diffuser plate 230, an optical sheet 240, a bottom chassis 250 for storing them, a bottom mold frame 260, and an upper mold frame 270. ).

The light source 210 is disposed below the liquid crystal display panels 110 and 120. As the light source 210, a line light source such as a plurality of Cold Cathode Fluorescent Lamps (CCFLs) or a Hot Cathode Fluorescent Lamps (HCFLs) arranged in parallel may be used. Unlike the illustrated example of FIG. 1, a surface light source may be used, or a point light source such as a light emitting diode (LED) may be used.

The reflective sheet 220 is installed in the bottom chassis 250 below the light source 210 to reflect the light emitted downward from the light source 210 toward the upper liquid crystal display panels 110 and 120, thereby increasing luminance efficiency. It plays a role. As the reflective sheet 220, a material having high elasticity and excellent light reflection, for example, polyethylene terephthalate (PET), or the like may be used. In addition, a thin film having a good elasticity may be used by coating a reflective film for increasing light reflection.

The diffusion plate 230 diffuses the light directly incident from the light source 210 upwardly and reflected through the reflection sheet 220 to increase the uniformity of luminance. As the preferred material of the diffusion plate 230, a transparent resin such as an acrylic resin, a polyurethane resin, or a silicone resin may be used. The surface and / or the inside of the diffusion plate 230 may have a diffusion particle pattern for scattering incident light.

In addition, a guide groove 263 for fastening with the bottom mold frame 260 is formed on at least one side of the diffusion plate 230. A more detailed description of the diffusion plate 260 and the guide groove 263 provided therein will be described later.

The optical sheet 240 is disposed above the diffuser plate 230 and serves to adjust the optical characteristics of the light passing through the diffuser plate 230. Examples of such an optical sheet 240 may be a diffusion sheet, a prism sheet, a protective sheet, and the like. In FIG. 1, the case where one optical sheet 240 is disposed is illustrated, but two or more of them may be disposed, or they may be arranged in combination.

In addition, a guide protrusion 241 for fastening with the bottom mold frame 260 is formed on at least one side of the optical sheet 240. More detailed description of the optical sheet 240 and the guide protrusion 263 provided therein will be described later.

The light source 210, the reflective sheet 220, the diffusion plate 230, and the optical sheet 240 may be formed on the lower housing member and the upper mold frame 270 including the bottom chassis 250 and the bottom mold frame 260. It is stored by. The bottom chassis 250 is located at the bottom of the backlight assembly 200 in the shape of a rectangular pillar with an open top, and the bottom mold frame 250 is a window frame having an open center in the center, and is disposed on the top of the bottom chassis 250. do. The light source 210, the reflective sheet 220, the diffusion plate 230, and the optical sheet 240 are accommodated in a space surrounded by the bottom surface 251 of the bottom chassis 250 and the bottom mold frame 260. In addition, the upper side of the center is opened, the upper mold frame 270 of the window frame covering the peripheral portion of the optical sheet 240 is disposed to prevent the separation of the housed members. The upper mold frame 270 also accommodates the upper liquid crystal display panels 110 and 120. The liquid crystal display panels 110 and 120 are provided with a top chassis 300 fastened to the bottom chassis 250 to prevent the liquid crystal display panels 110 and 120 from flowing and escaping.

On the other hand, at least one side of the bottom mold frame 260 is provided with a guide portion 262 for guiding the diffusion plate 230 and / or the optical sheet 240 and to ensure a stable coupling therewith.

Hereinafter, the guide part 262 of the bottom mold frame 260, the guide groove 231 of the diffusion plate 230, and the guide protrusion 241 of the optical sheet 240 will be described in more detail.

2 is a perspective view of a mold frame of the backlight assembly according to an embodiment of the present invention. 3 is a perspective view of a guide part of the mold frame of FIG. 2.

Referring to FIG. 2, the bottom mold frame 260 has a rectangular bottom surface 261 extending in a predetermined width from the bottom of the side wall 263 to the open window side in the middle. A guide part 262 is disposed on at least one side of the bottom surface 261. Preferably, two guide parts 262 may be disposed on one side of the bottom surface 261 and the other side opposite thereto.

The guide part 262 protrudes from the sidewall 263 of the bottom mold frame 260 toward the bottom surface 261 and includes two protruding walls 262a and 262b spaced apart from each other. The two protruding walls 262a and 262b are connected by the side wall 263 of the bottom mold frame 260. The space surrounded by the two protruding walls 262a and 262b and the side wall 263 of the bottom mold frame 260 becomes an optical sheet guide space. Such an optical sheet guide space may be, for example, 'c' shaped.

The connection surfaces of the protruding walls 262a and 262b may be prepared separately from the bottom mold frame 260 and attached to the sidewalls 263 of the bottom mold frame 260. That is, after preparing a 'c' shaped guide emboss consisting of two protruding walls 262a and 262b and their connecting surfaces 263c as shown in FIG. 3, the sidewalls of the bottom mold frame 260 are prepared. 263). In the following embodiments, although the guide embossment is used as the guide part 262, the case in which the bottom mold frame 260 is integrally provided may be applied in the same manner.

The separation distance L1 between the two protruding walls 262a and 262b of the guide part 262 is adjusted to allow the guide protrusion 241 of the optical sheet 240 to be inserted therein, and the two protruding walls 262a and 262b. The distance between the outer surface of the (L2) is adjusted so that the guide groove 231 of the diffusion plate 230 can be fastened. In addition, the height h of the guide portion 262 is designed to be larger than their total thickness so as to include both the diffusion plate 230 and the optical sheet 240 to be stacked.

Hereinafter, the fastening shape of the guide part 262, the diffusion plate 230, and the optical sheet 240 as described above will be described in more detail.

4 is a perspective view of a diffusion plate of a backlight assembly according to an embodiment of the present invention.

Referring to FIG. 4, the diffusion plate 230 includes a guide groove 231 on one side of the diffusion plate 230 to correspond to the guide portion 262 of the bottom mold frame 260. The guide groove 231 may be, for example, a curved shape of the letter 'C', and the width L3 of the guide groove 231 is the distance L2 between the outer surfaces of the protruding walls 262a and 262b of the guide portion 262. It is formed to be larger than).

5 is a plan view illustrating the diffusion plate of FIG. 4 coupled to the guide unit of FIG. 3. 6 and 7 are cross-sectional views taken along lines VI-VI 'and VII-VII' of FIG. 5, respectively.

5 to 7, the diffusion plate 230 is fastened so that the guide groove 231 surrounds the outer surface of the guide part 262. In this case, preferably, the outer surfaces of the protruding walls 262a and 262b of the guide portion 262 may contact the inner surfaces of the guide grooves 231, thereby preventing the flow of the diffusion plate 230. In addition, the sides of the diffusion plate 230 are in contact with or adjacent to the side wall 263 of the bottom mold frame 260, so that the periphery of the diffusion plate 230 and the bottom surface 261 of the bottom mold frame 260 It may overlap and be supported.

The fastening of the guide part 262 and the guide groove 231 as described above pushes the diffusion plate 230 toward the sidewall 263 of the bottom mold frame 260, or pushes the diffusion plate 230 to the bottom mold frame 260. Fastening is easy because it can be made by seating down from the top of the, and because the fastening surface is wide, the horizontal or vertical flow of the diffusion plate 230 can be prevented. In addition, when the height h of the guide part 262 is sufficient, the possibility that the guide groove 231 of the diffusion plate 230 is removed from the guide part 262 may be reduced, thereby maintaining a more stable fastening state.

8 is a perspective view of an optical sheet of a backlight assembly according to an embodiment of the present invention.

Referring to FIG. 8, the optical sheet 240 includes a guide protrusion 241 on one side of the optical sheet 240 to correspond to the guide portion 262 of the bottom mold frame 260. For example, the guide protrusion 241 may have a shape protruding as a letter 'C', and the width L4 of the guide protrusion 241 is smaller than the separation distance L4 between the protruding walls 262a and 262b of the guide part 262. It is formed to.

9 is a plan view of the diffusion plate of FIG. 4 and the optical sheet of FIG. 8 coupled to the guide unit of FIG. 3. 10 and 11 are cross-sectional views taken along the line VII'- 'and XI-XI' of FIG. 9, respectively.

9 to 11, the guide protrusion 241 of the optical sheet 240 guides the optical sheet 240 defined by the protruding walls 262a and 262b and the connecting surface 262c of the guide portion 262. It is inserted into the space. At this time, preferably, the inner surfaces of the protruding walls 262a and 262b of the guide part 262 contact the guide protrusion 241 to prevent the flow of the optical sheet 240. Since the side of the optical sheet 240 is spaced apart from the sidewall 263 of the bottom mold frame 260 at the surface where the guide protrusion 241 is formed, the side of the optical mold 240 overlaps the bottom surface 261 of the bottom mold frame 260. Although not necessarily, since it is disposed on the diffusion plate 230 supported by the bottom surface 261 of the batam mold frame 260, the supporting stability of the optical sheet 240 is not a problem.

The fastening of the guide part 262 to the guide protrusion 241 pushes the optical sheet 240 toward the sidewall 263 of the bottom mold frame 260, or moves the optical sheet 240 from the top of the bottom mold frame to the bottom thereof. Fastening is easy because it can be made by seating, and because the fastening surface is wide, the horizontal or vertical flow of the optical sheet 240 can be prevented. In addition, when the height h of the guide part 262 is sufficient, the possibility of the guide protrusion 241 of the optical sheet 240 coming off from the guide part 262 is also reduced, so that a more stable fastening state can be maintained.

Meanwhile, the vertical flow prevention of the optical sheet 240 and the fastening stability of the guide part 262 and the guide protrusion 241 as described above may be further ensured by the upper mold frame disposed on the optical sheet 240. And may be easily inferred from the embodiment of FIG. 12 described below.

12 is a partial cross-sectional view of a backlight assembly according to another embodiment of the present invention. In this embodiment, the same structure as in the embodiment of the present invention will be omitted or simplified, and will be described based on the difference.

Referring to FIG. 12, unlike the embodiment of FIG. 10, three optical sheets 240a, 240b, and 240c are stacked in this embodiment. The three optical sheets 240 are all formed with the guide protrusion 241 in the same site | part. In FIG. 12, the guide protrusions 241a, 241b, and 241c have the same size, but the sizes of the guide protrusions 241a, 241b, and 241c may be different from each other in order to distinguish the order of the respective optical sheets 240. .

The upper mold frame 270 is disposed above the optical sheets 240a, 240b, and 240c. The upper mold frame 270 is disposed to overlap with the guide protrusions 241a, 241b and 241c of the optical sheets 240a, 240b and 240c and the periphery of the optical sheets 240a, 240b and 240c, so that the upper portion of the optical sheet 240 is perpendicular to the optical sheet 240. Prevent directional flow and departure.

Meanwhile, in the above embodiments, the direct type backlight assembly has been described, but the present invention may be applied to the edge type backlight assembly. In this case, the light guide plate may be provided and the diffusion plate may not be provided. The light guide plate may have a guide groove like the diffusion plate in the above embodiments, and the shape of the other optical sheet and the bottom mold frame may be the same as in the above embodiments. Since such application to the edge type backlight assembly can be easily understood or inferred by those skilled in the art, more detailed description will be omitted.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, according to the backlight assembly in the embodiments of the present invention, the guide groove provided in the diffusion plate and / or the guide protrusion provided in the optical sheet may be easily fastened to the guide part provided in the bottom mold frame. Stability can be improved. Therefore, deterioration in optical characteristics of the emitted light due to the flow of the optical sheet or the like can be prevented.

Claims (11)

A bottom mold frame having at least one guide surface including a connecting surface and two protruding walls spaced apart from each other to protrude therefrom to define an optical sheet guide space; And And an optical sheet disposed on the bottom mold frame, the optical sheet including a guide protrusion inserted into the optical sheet guide space of the guide part, wherein the guide part is disposed on a bottom surface of the bottom mold frame. According to claim 1, And the connection surface of the guide part is attached to a side wall of the bottom mold frame. According to claim 1, The connecting surface of the guide portion is a backlight assembly of the bottom mold frame. The method according to claim 2 or 3, The guide unit is a backlight assembly having a '' 'shape. The method according to claim 2 or 3, And the separation distance between the two protruding walls is greater than or equal to the width of the guide protrusion of the optical sheet. The method of claim 5, And an upper mold frame overlapping at least a periphery of the optical sheet on the optical sheet. The method of claim 6, And a diffuser plate disposed between the mold frame and the optical sheet and having a guide groove fastened to the outside of the protruding wall of the guide portion. The method of claim 7, wherein And a width of the guide groove is greater than or equal to a distance between outer surfaces of the two protruding walls. A liquid crystal display panel which displays an image; And A bottom part disposed under the liquid crystal panel to provide light to the liquid crystal panel, the bottom part including a guide part including at least one connection surface and two protrusion walls spaced apart from each other to protrude therefrom to define an optical sheet guide space; A mold frame, and an optical sheet disposed on the bottom mold frame, the optical sheet including a guide protrusion inserted into the optical sheet guide space of the guide part, wherein the guide part is disposed on a bottom surface of the bottom mold frame. Liquid crystal display comprising a backlight assembly. The method of claim 9, And the connection surface of the guide part is attached to a side wall of the bottom mold frame. The method of claim 9, The connecting surface of the guide portion is a backlight assembly of the bottom mold frame.

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