KR20070069655A - Fixing member for optical sheets, backlight assembly and liquid crystal display device including the same - Google Patents

Abstract

An optical sheet fixing member, a backlight assembly having the optical sheet fixing member, and an LCD(Liquid Crystal Display) are provided to prevent an optical sheet from waving and easily handle the optical sheet by fixing the optical sheet with use of the optical sheet fixing member. A optical sheet fixing member includes a receiving part(240) and a body(230). The receiving part fixes a plurality of optical sheets(125) according to surface contact. The body is fixed to a receiving member in which a backlight assembly is located. The receiving part includes a depression(260) for receiving the optical sheets, a through-hole(270) penetrating the groove, and combining members(210,220).

Description

Fixing member for optical sheet, backlight assembly and liquid crystal display including same {FIXING MEMBER FOR OPTICAL SHEETS, BACKLIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY DEVICE INCLUDING THE SAME}

1 is an exploded perspective view of a direct type liquid crystal display device according to the related art.

2 is a cross-sectional view taken along the line A-A of FIG.

3 is a plan view of the optical sheet and the sheet fixing projection according to the prior art.

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

5 is a cross-sectional view taken along the line B-B of FIG. 4.

Figure 6 is a cross-sectional view before fastening of the fixing member according to the present invention.

7 shows the load distribution of the optical sheet due to the fixing member according to the present invention.

※ Explanation of code for main member of drawing ※

26a: stepped stepped surface 124: diffusion plate

125: optical sheets 126b: projection

200: fixing member 210: bolt

220: nut 230: body

240: receiving portion 250: opening

260: groove 270: through hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a plurality of optical sheet fixing members included in a backlight assembly, a backlight assembly including the same, and a liquid crystal display device, and more particularly, wave phenomena and sheets of an optical sheet that may occur in a direct backlight structure. The present invention relates to a plurality of optical sheet fixing members included in a backlight assembly capable of preventing breakage of a fixing protrusion, a backlight assembly including the same, and a liquid crystal display device.

In general, the liquid crystal display (LCD) is expanding its application range due to features such as lightweight, thin, low power drive, full-color, high-resolution implementation. Currently, LCDs are used in computers, notebooks, PDAs, telephones, TVs, and audio / video devices. Such a liquid crystal display device adjusts the amount of light transmitted according to an image signal applied to a plurality of control switches arranged in a matrix to display a desired image on a panel of the liquid crystal display device.

Since the LCD does not emit light by itself, a light source such as a backlight is required. There are two types of backlights for liquid crystal display devices, an edge type method and a direct type method, depending on the position of the light source.

In the edge type method, a light source is provided at an edge of the liquid crystal display panel, and the light generated from the light source is irradiated to the liquid crystal display panel through a transparent light guide plate disposed under the liquid crystal display panel. It has good uniformity of light, long life, and is advantageous for thinning a liquid crystal display device, and is generally used to irradiate light to medium and small size liquid crystal display panels. On the other hand, the direct type is a method of directly irradiating the entire surface of the liquid crystal display panel by placing a plurality of light sources under the liquid crystal display panel. This can ensure high luminance and is generally used to irradiate light onto large and medium sized liquid crystal display panels.

In such a large and medium direct type liquid crystal display, in order to fix a plurality of optical sheets, openings are formed in the side surfaces of the optical sheets and inserted into the sheet fixing protrusions formed in the lower chassis or the mold frame to fix the optical sheets. Hereinafter, a schematic structure and a problem thereof of a conventional direct type liquid crystal display will be described with reference to FIGS. 1 to 3.

1 is an exploded perspective view of a direct type liquid crystal display device according to the prior art, FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1, and FIG. 3 is a plan view of the optical sheet and the projection for fixing the sheet according to the prior art.

1 to 3, a direct type liquid crystal display according to the related art includes a liquid crystal display panel 10, a backlight assembly 20 including a reflector 27, and a backlight assembly 20 for mounting the backlight assembly 20. The mold frame 30, the upper chassis 40 to cover a predetermined region and a side portion of the liquid crystal display panel 10 and the direct backlight assembly 20, and a lamp driving circuit disposed below the backlight assembly 20 (not shown). Not included).

The liquid crystal display panel 10 is injected between the thin film transistor substrate 12, the color filter substrate 11 corresponding to the thin film transistor substrate 12, and the thin film transistor substrate 12 and the color filter substrate 11. It includes a liquid crystal layer (not shown). The display device may further include a polarizer (not shown) formed to correspond to the upper portion of the color filter substrate 11 and the lower portion of the thin film transistor substrate 12.

The backlight assembly 20 includes a lamp unit 21 for generating light, a reflector 27 disposed below the lamp unit 21, a diffuser plate 24 disposed above the lamp unit 21, and an optical sheet. Field 25. The lamp unit 21 includes a plurality of bar lamps 21a arranged in parallel, a plurality of lamp fixing parts 22 for fixing the lamps, and a lamp support part in which the plurality of lamp fixing parts 22 are housed. 23).

The lower chassis 26 is formed in a box shape of a rectangular parallelepiped with an upper surface open to form a storage space having a predetermined depth therein. That is, the lower chassis 260 includes a chassis bottom surface and first to fourth chassis sidewalls that protrude vertically from each edge from the chassis bottom surface. The apparatus further includes first and third chassis inclined surfaces that are inclined at an angle from the first and third chassis sidewalls located on opposite sides of the outermost lamp and extended toward the chassis bottom surface. In addition, a stepped stepped surface is formed at an upper end between the first and third chassis sidewalls and the first and third chassis inclined surfaces. Thus, the bottom reflecting surface and the side reflecting surface of the reflecting plate 27 are located on the chassis bottom surface and the chassis inclined surface of the lower chassis 26, respectively. In addition, a sheet fixing protrusion 26b for fixing the optical sheets 25 protrudes from the stepped stepped surface, and a sheet fixing hole 25b is formed at one side of the optical sheets 25. . The sheet fixing protrusion 26b and the sheet fixing hole 25b may fix and seat the optical sheets 25 sequentially.

However, referring to FIG. 3, which shows a load distribution of the optical sheet according to the prior art, the optical sheet 25 and the sheet fixing protrusion 26b are configured to be in point contact with each other only in a part of the optical sheet. Local concentrated loads are generated at the fixing portions of the 25 and the sheet fixing protrusions 26b to easily generate waves in the optical sheet, and the sheet fixing protrusions 26b are formed on the lower chassis 26 when the liquid crystal display is impacted. Often breakage occurs from.

Accordingly, an object of the present invention is to provide a backlight assembly capable of preventing wave generation of an optical sheet by providing a fixing member for an optical sheet in surface contact with the optical sheet, and a liquid crystal display device including the same.

In addition, another object of the present invention is to provide a backlight assembly and a liquid crystal display including the same that can facilitate the handling of the optical sheet by fixing the optical sheet using the fixing member according to the present invention.

A plurality of optical sheet fixing members included in the backlight assembly according to the present invention includes a receiving portion for fixing the optical sheets by surface contact, and a body portion fixed to the receiving member on which the backlight assembly is mounted.

In this case, a groove for accommodating the optical sheets is formed in the accommodating part, a through hole is formed across the groove, and a fastening member is fastened through the through hole to reduce the gap between the grooves. The fastening member may include a bolt and a nut. The body portion is formed with an opening that is engaged with the protrusion formed in the housing member. Preferably, the through-holes formed in the accommodation portion and the openings formed in the body portion are disposed to be offset from each other.

In addition, the backlight assembly mounted to the receiving member according to the present invention provides a lamp unit having a plurality of lamps for generating light, a plurality of optical sheets disposed on the lamp unit, and fixing the optical sheets by surface contact. And a fixing part for an optical sheet including a receiving part and a body part fixed to the receiving member on which the backlight assembly is mounted.

On the other hand, the liquid crystal display according to the present invention includes a backlight assembly, a liquid crystal display panel disposed on the backlight assembly, and a receiving member for supporting the backlight assembly and the liquid crystal display panel.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various forms, and the present embodiments merely make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention. Like numbers refer to like elements in the drawings.

4 is an exploded perspective view of a direct type liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along the line B-B of FIG. 4.

4 and 5, the direct type liquid crystal display according to the present invention includes a liquid crystal display panel 100, a backlight assembly 120 including a reflection plate 127 having a scattering pattern, and a backlight assembly 120. A mold frame 130 for attaching the light emitting unit, an upper chassis 140 for covering a predetermined region and a side portion of the liquid crystal display panel 100 and the backlight assembly 120, and a lamp driving circuit disposed under the backlight assembly 120. (Not shown). In addition, the direct type liquid crystal display according to the present invention further includes a fixing member 200 for fixing the optical sheets 125 of the backlight assembly 120 on the lamp unit 121.

The liquid crystal display panel 100 includes a thin film transistor substrate 112, a data side and gate side tape carrier package (TCP) 113 and 114 connected to the thin film transistor substrate 112, a data side and Data side and gate side printed circuit boards 115 and 116 respectively connected to the gate side tape carrier packages 113 and 114, the color filter substrate 111 corresponding to the thin film transistor substrate 112, and the thin film transistor substrate ( And a liquid crystal layer (not shown) injected between the 112 and the color filter substrate 111. The display device may further include a polarizer (not shown) formed to correspond to the upper portion of the color filter substrate 111 and the lower portion of the thin film transistor substrate 112.

Here, the color filter substrate 111 is a substrate in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process. A common electrode (not shown) made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the front surface of the color filter substrate 111.

The thin film transistor substrate 112 is a transparent glass substrate on which a thin film transistor (TFT) and a pixel electrode are formed in a matrix form. The data line is connected to the source terminal of the TFTs, and the gate line is connected to the gate terminal. Further, a pixel electrode (not shown) made of a transparent electrode made of a transparent conductive material is formed in the drain terminal. When an electrical signal is input to the data line and the gate line, each TFT is turned on or turned off to apply an electrical signal necessary for pixel formation to a drain terminal.

That is, as described above, when power is applied to the gate terminal and the source terminal of the thin film transistor substrate 112 and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate 111. Due to this electric field, the arrangement of the liquid crystal injected between the thin film transistor substrate 112 and the color filter substrate 111 is changed, and the light transmittance is changed according to the changed arrangement to obtain a desired image.

The data side and gate side tape carrier packages 113 and 114 are respectively connected to the data line and the gate line of the thin film transistor substrate 112 to apply the data driving signal and the gate driving signal to the thin film transistor. In this case, the driving IC may be mounted in the tape carrier packages 113 and 114. The data side and gate side printed circuit boards 115 and 116 are connected to the data side and gate side tape carrier packages 113 and 114 to apply external image signals and gate driving signals.

The backlight assembly 120 includes a lamp unit 121 for generating light, a reflector plate 127 disposed under the lamp unit 121, a diffuser plate 124 and optical sheets disposed above the lamp unit 121. 125 and a fixing member 200 for fixing the optical sheets 125 to the lower chassis 126.

Here, the lamp unit 121 includes a plurality of bar lamps 121a arranged in parallel, a plurality of lamp fixing parts 122 for fixing the lamps, and a lamp support part in which the plurality of lamp fixing parts 122 are accommodated. 123. The lamp 121a generates light by a driving voltage applied from the outside. The plurality of lamps 121a mainly use cold cathode fluorescent lamps, and each lamp 121a includes a glass tube, inert gases contained in the glass tube, and a negative electrode and a positive electrode installed at both ends of the glass tube. At this time, the phosphor is coated on the inner wall of the glass tube. The lamps 121a are preferably arranged at equal intervals for luminance uniformity, and the number of lamps 121a is preferably determined according to the required luminance. Each of the lamp fixing parts 122 includes a base substrate on which one end of the lamp is seated, and a fixing clip and a fixing protrusion for protruding from the base substrate to fix the lamp. The lamp support 123 includes a bottom surface on which the plurality of lamp fixing parts 122 are mounted and a side wall extending vertically from the bottom surface. In this case, the lamp fixing part 122 may be formed of a conductive material to apply power to the electrode of the lamp 121a. In this case, the lamp support 123 must be formed of an insulating material to electrically insulate the electrode of the lamp 121a from the lower chassis 126.

The reflecting plate 127 has a bottom reflecting surface at which the lamp 121a is positioned at an upper portion thereof, and a side reflecting surface having a predetermined inclination from the bottom reflecting surface in a direction parallel to the lamp at edges corresponding to opposite sides of the lamp unit 121. It includes. The reflective plate 127 may be attached to the lower chassis 126 by an adhesive, a double-sided adhesive tape, or the like. Moreover, the reflector plate 127 may be integrally formed with the lower chassis.

The diffusion plate 124 directs the light incident from the plurality of lamps toward the front of the liquid crystal display panel 100, and diffuses the light to have a uniform distribution in a wide range so that the liquid crystal display panel 100 is irradiated. As the diffusion plate 124, it is preferable to use a film made of a transparent resin coated with a predetermined light diffusion member on both surfaces.

The optical sheets 125 serve to change the light incident at an oblique angle among the light incident to the optical sheet 125 to be emitted vertically. This is because the light efficiency increases when the light incident on the liquid crystal display panel 100 is perpendicular to the liquid crystal display panel 100. Therefore, at least one optical sheet 125 may be disposed between the diffuser plate 124 and the liquid crystal display panel 100 to vertically convert the light emitted from the diffuser plate 124.

The lower chassis 126 is formed in a box shape of a rectangular parallelepiped with an upper surface open to form a storage space having a predetermined depth therein. That is, the lower chassis 126 includes a chassis bottom surface and first to fourth chassis side walls that protrude vertically from each edge from the chassis bottom surface. The apparatus further includes first and third chassis inclined surfaces that are inclined at an angle from the first and third chassis sidewalls located on opposite sides of the outermost lamp and extended toward the chassis bottom surface. In addition, a stepped stepped surface 26a is formed at an upper end between the first and third chassis sidewalls and the first and third chassis inclined surfaces. Thus, the bottom reflecting surface and the side reflecting surface of the reflecting plate 127 are positioned on the chassis bottom surface and the chassis inclined surface of the lower chassis 126, respectively.

In addition, the stepped stepped surface 26a has a protrusion 126b fastened to the fixing member 200 for fixing the optical sheets 125. On the other hand, the fixing member 200 is shown in only one side of the optical sheet 125 in FIG. 4, but for the sake of simplicity of the drawing, according to the present invention on both sides or all sides of the optical sheet 125 The fixing member 200 may be formed. The fixing member 200 and the protrusion 126b will be described later in more detail.

On the other hand, the driving circuit (not shown) includes a plurality of driving voltage generators (not shown) disposed on the rear surface of the lower chassis 126 to generate the driving voltage. Here, the driving voltage generation unit includes at least one inverter for boosting the low voltage AC voltage applied from the outside to the high voltage AC voltage for driving the lamp 121a. The driving voltage generator and the lamp are electrically connected by wires.

The mold frame 130 is formed in a rectangular frame shape and includes a flat portion and sidewall portions bent at right angles therefrom. A mounting portion is formed on the flat portion to mount the liquid crystal display panel 100. As shown in the drawing, the mounting portion may use a fixing protrusion 131 that contacts and positions the edge side of the liquid crystal display panel 100, respectively, or may be formed using a predetermined stepped step surface. In the mold frame 130, the optical sheets 125, the diffusion plate 124, the fixing member 200, the lamp unit 121, and the reflecting plate 127 are fixed to the lower chassis 126. The lower chassis 126 and the mold frame 130 form an accommodating member for accommodating the liquid crystal display panel 100 and the backlight assembly 120.

The upper chassis 140 is configured in the form of a rectangular window frame having a flat portion and sidewall portions bent at right angles therefrom. The planar portion of the upper chassis 140 supports a portion of the edge of the liquid crystal display panel 100 at the bottom thereof, and the sidewall portion is coupled to face the sidewalls of the lower chassis 126. The upper chassis 140 and the lower chassis 126 are preferably made of metal having high strength, light weight, and low deformation.

6 is a cross-sectional view before fastening of the fixing member 200 according to the present invention. Referring to FIG. 6, a fixing member 200 according to the present invention is provided between the mold frame 130 and the stepped step surface 26a of the lower chassis 126. The fixing member 200 includes a body portion 230 fastened to the protrusion 126b and a receiving portion 240 for fixing the optical sheets 125. The accommodating part 240 has a groove 260 for accommodating the optical sheets 125 and a through hole for fixing the optical sheets 125 to the groove 260 by bolts 210 and nuts 220. 270 is formed. A bolt 210 is inserted through one end of the through hole 270, and a nut 220 is provided at the other end of the through hole 270. Grooves are formed at both ends of the through hole 270 so that the head of the bolt 210 and the nut 200 do not protrude. The body portion 230 has an opening 250 through which the protrusion 126b penetrates to fix the fixing member 200 to the lower chassis 126. When the optical sheets 125 are provided in the grooves 260 of the accommodating part 240, the bolt 210 and the nut 220 open the through holes 270 to reduce the gap of the grooves 260. Is fastened through. As a result, the optical sheets 125 are fixed to the fixing member 200 and are in surface contact with the fixing member 200 instead of point contact. Thereafter, as described above, the fixing member 200 is engaged with the protrusion 126b formed on the stepped step surface 26a of the lower chassis 126 through the opening 250 formed in the body portion 230. Accordingly, the optical sheets 125 are in surface contact with the fixing member 200 without being in point contact with the protrusion 126b as in the related art. As a result, no local load distribution occurs in the optical sheet 125, and no wave of the optical sheet occurs. In addition, by fixing the optical sheets 125 using the fixing member 200 according to the present invention, since the optical sheet itself does not need to be handled unlike in the prior art, the handling of the optical sheet is facilitated.

Meanwhile, although the fixing member is manufactured as a single member in the present embodiment, it will be appreciated that the present invention is not limited thereto and that the fixing member according to the present invention may be composed of two corresponding members.

7 is a view showing a load distribution of the optical sheet due to the fixing member according to the present invention. As shown in FIG. 7, the optical sheets 125 are in surface contact with the fixing member 200 according to the present invention rather than in point contact. In addition, the through hole formed in the receiving portion, that is, the bolt 210 and the opening formed in the body portion, that is, the protrusion 126b, are disposed to be offset from each other to form a more uniform load distribution on the optical sheet 125. As a result, a local load distribution does not occur in the optical sheet 125 and a uniform load distribution is formed throughout.

Meanwhile, in one embodiment of the present invention, the protrusion 126b is formed on the stepped end face 26a of the lower chassis 126, but the present invention is not limited thereto and is formed on the bottom surface of the mold frame 130. After the fixing member 200 according to the present invention to fix the optical sheets 125 is mounted on the stepped step surface 26a of the lower chassis 126, and then the mold frame formed with a projection on the fixing member 200 By attaching to the same effect as in the embodiment of the present invention can be achieved.

According to the present invention, by providing a backlight assembly having a fixing member in surface contact with an optical sheet and a liquid crystal display including the same, wave generation of the optical sheet and breakage of the sheet fixing protrusion may be prevented.

In addition, the present invention facilitates handling of the optical sheets by providing a backlight assembly for fixing the optical sheets using the fixing member according to the present invention and a liquid crystal display including the same.

Claims (7)

In the fixing member for a plurality of optical sheets included in the backlight assembly, An accommodation portion for fixing the optical sheets by surface contact; Characterized in that the body portion is fixed to the housing member on which the backlight assembly is mounted, Fixing member for optical sheet. The method according to claim 1, The receiving portion is characterized in that a groove for receiving the optical sheet is formed, a through hole is formed across the groove, the fastening member is fastened through the through hole to reduce the gap between the groove, Fixing member for optical sheet. The method according to claim 2, The fastening member is characterized in that it comprises a bolt and a nut, Fixing member for optical sheet. The method according to claim 1, The body portion is characterized in that the opening is formed to be engaged with the projection formed on the receiving member, Fixing member for optical sheet. The method according to claim 2 or 4, Characterized in that the through-hole formed in the receiving portion and the opening formed in the body portion are arranged to be offset from each other, Fixing member for optical sheet. In the backlight assembly mounted to the receiving member, A lamp unit having a plurality of lamps for generating light; A plurality of optical sheets disposed on the lamp unit; And And a holding member for fixing the optical sheets by surface contact, and a fixing member for the optical sheet including a body portion fixed to the receiving member on which the backlight assembly is mounted. Backlight assembly. A backlight assembly according to claim 6, A liquid crystal display panel disposed on the backlight assembly; It characterized in that it comprises a housing member for supporting the backlight assembly and the liquid crystal display panel, Liquid crystal display.

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