KR20060084194A - A backlight assembly improving a fixing structure of optical sheets and a flat display device provided with the same - Google Patents

Abstract

The present invention relates to a backlight assembly having an improved fixing structure of an optical sheet and a flat panel display device having the same. To this end, the backlight assembly according to the present invention integrates a plurality of optical sheets through a light source for emitting light, a plurality of optical sheets for improving the brightness of light emitted from the light source, and openings formed at edges of the plurality of optical sheets. And a fixing member for fixing. Here, the fixing member forms a fixing space for fixing the plurality of optical sheets, and the length of the fixing space along the direction intersecting with the plurality of optical sheets is larger than the sum of the thicknesses of the plurality of optical sheets.

Optical sheet, fixing member, backlight assembly, step

Description

BACKLIGHT ASSEMBLY IMPROVING A FIXING A FIXING STRUCTURE OF OPTICAL SHEETS AND A FLAT DISPLAY DEVICE PROVIDED WITH THE SAME}

1 is an exploded perspective view of a backlight assembly according to a first embodiment of the present invention.

2 is a combined perspective view of a backlight assembly according to a first embodiment of the present invention.

3 is a partial cross-sectional view taken along line BB of FIG. 2.

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

5 is an exploded perspective view of a flat panel display device having a backlight assembly according to a first embodiment of the present invention.

The present invention relates to a backlight assembly having an improved fixing structure of an optical sheet and a flat panel display device having the same, and more particularly, to a backlight assembly having a structure capable of preparing for thermal expansion of an optical sheet while fixing the optical sheet at once. It relates to a flat panel display device.

With the recent rapid development of semiconductor technology, the demand for liquid crystal display devices that are smaller and lighter and has improved performance is exploding.

Recently, liquid crystal displays (LCDs), which have been in the spotlight, have advantages such as miniaturization, light weight, and low power consumption, and as an alternative means to overcome the disadvantages of the conventional cathode ray tube (CRT). It has been attracting attention and is currently used in almost all information processing equipment that requires a display device.

A general liquid crystal display device applies voltage to a specific molecular array of a liquid crystal to convert it into another molecular array, and visually changes optical properties such as birefringence, photoreactivity, dichroism, and light scattering characteristics of the liquid crystal cell emitted by the molecular array. It is a light-receiving display device which converts into a change and displays information using the modulation of the light by a liquid crystal cell.

In such a liquid crystal display, three or four optical sheets are used to increase the luminance of light emitted from a light source. Since these optical sheets are all made separately, the optical sheets must be assembled one by one. Therefore, since very thin optical sheets must be assembled, there is a problem that not only takes a long time to assemble, but also scratches on the optical sheets during handling.

In addition, there is a problem that not only the foreign material is introduced between the optical sheet due to static electricity, but also the sheetum is generated due to interference with peripheral components due to misalignment of the optical sheet. In particular, optical sheets used in large LCD products, which are gradually increasing in demand, have a considerable weight, which may cause reliability problems due to sheet slippage during impact test or vibration test.

The present invention is to solve the above problems, to improve the fixing structure of the optical sheet to provide a backlight assembly having a structure that can be prepared for thermal expansion of the optical sheet.

In addition, the present invention is to provide a flat panel display device having the above-described backlight assembly.

A backlight assembly according to the present invention for achieving the above object is a light source for emitting light, a plurality of optical sheets for improving the brightness of the light emitted from the light source, and openings formed in the edges of the plurality of optical sheets And a fixing member penetrating and fixing the plurality of optical sheets integrally. Here, the fixing member forms a fixing space for fixing the plurality of optical sheets, and the length of the fixing space along the direction intersecting with the plurality of optical sheets is larger than the sum of the thicknesses of the plurality of optical sheets.

The backlight assembly according to the present invention may further include a bottom chassis for accommodating the light source and the optical sheet, and the fixing member may be seated and supported on the stepped portion formed on the outer surface of the bottom chassis along the arrangement direction of the light source.

The backlight assembly according to the present invention may further include a diffuser plate positioned between the light source and the optical sheet to diffuse the light emitted from the light source.

Here, the diffusion plate is preferably seated and supported between the fixing member and the bottom chassis.

In addition to the stepped portion formed on the outer surface of the bottom chassis, it is preferable that another stepped portion is formed on the outer surface of the bottom chassis, and the diffusion plate is seated and supported on the other stepped portion.

The fixing member may include an insertion portion for fixing the optical sheet through the opening, and the insertion portion of the fixing member may be connected to the upper and lower plates of the fixing member.

The insert of the fixing member may be integrally connected to the lower plate of the fixing member, and the insert may be detachably connected to a hole formed in the upper plate of the fixing member.

The backlight assembly according to the present invention further includes a mold frame covering the edge of the bottom chassis to fix the optical sheet, and the upper plate portion of the fixing member is inserted into and fixed to the recess formed in the mold frame.

The light source may be composed of a plurality of lamps arranged spaced apart from each other along the width direction thereof.

A flat panel display device according to the present invention includes a flat panel display panel for displaying an image, and the aforementioned backlight assembly for supplying light to the flat panel display panel.

Here, the flat panel display panel may be a liquid crystal display panel.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. These embodiments of the present invention are merely for illustrating the present invention, but the present invention is not limited thereto.                     

1 is an exploded perspective view of a backlight assembly 70 according to a first embodiment of the present invention, and shows a direct type backlight assembly mainly used in a large TV or the like.

The structure of the backlight assembly 70 shown in FIG. 1 is merely for illustrating the present invention, but the present invention is not limited thereto. Therefore, the present invention can also be applied to backlight assemblies having other structures.

The backlight assembly 70 is formed by combining an optical sheet 72, a diffusion plate 74, a light source 76, a light source holder (not shown), and the like, and the backlight assembly 70 is emitted from the light source 76. The light is diffused to make it uniform and then emitted in the Z-axis direction. The bottom chassis 75 located below the backlight assembly 70 houses internal components including a light source 76, a light source holder (not shown), and a frame mold side 77. A mold frame 71 is fixedly coupled on the bottom chassis 75.

The plurality of light sources 76 that emit light are arranged to be fixedly spaced apart from each other by a predetermined distance on the bottom chassis 75 along the width direction thereof, and the reflective sheet 79 is disposed on the bottom surface of the bottom chassis 75. It is provided to reflect the light emitted from the light source 76. Although a lamp is shown in FIG. 1 as a light source, this is merely to illustrate the present invention, but the present invention is not limited thereto. Therefore, a light emitting diode (LED) may be used instead of a lamp, and a line light source or a surface light source may be used. CCFL (cold cathode flourescent lamp, cold cathode fluorescent lamp) may be used as the lamp. A light source holder (not shown) is installed at an end of the light source 76 to fix and support the light source 76. A plurality of light source holders (not shown) are covered and fixed with a frame mold side 77.

Light emitted from the plurality of light sources 76 is evenly spread through the diffusion plate 74. This makes it possible to distribute the light more uniformly. The luminance of the light is improved and supplied to the upper part through the plurality of optical sheets 72 positioned on the diffusion plate 74. The plurality of optical sheets 72 are integrally fixed using the fixing member 10. Although FIG. 1 illustrates the fixing of the optical sheet 72 with fixing members 10 positioned at both edges along the Y-axis direction, the position of the fixing member 10 is merely for illustrating the present invention and the present invention. It is not limited to this. Therefore, the fixing member 10 can also be provided in another position. Through the diffusion plate 74 and the optical sheet 72 provided in this way it is possible to supply a light uniformly improved brightness.

The back of the bottom chassis 75 is provided with an inverter (73) which is a printed circuit board (PCB) for power supply. The inverter 73 transforms an external power supply to a constant voltage level and applies it to the light source 76. The inverter 73 is covered with a shield case 77 to protect the inverter 73. A plurality of openings 771 are formed in the shield case 77 to help heat the inverter 73.

The enlarged circle of FIG. 1 shows the cross section which cut the optical sheet 72 provided with the fixing member 10 along the AA line. As shown in the enlarged circle of FIG. 1, an opening 721 is formed at the edge of the optical sheet 72. The optical sheet 72 is integrally fixed to the fixing member 10 through the opening 721 formed as described above. The fixing member 10 includes an upper plate portion 101, a lower plate portion 103, an insertion portion 105, and a fixing portion 107. In addition, other parts may be included as needed.

The insertion portion 105 of the fixing member 10 penetrates through the opening 721 of the optical sheet 72 to fix the optical sheet 72. The insertion portion 105 of the fixing member 10 may be connected to the upper plate portion 101 and the lower plate portion 103 of the fixing member 10. The optical sheet 72 is fixed to the bottom chassis 75 through the fixing member 10.

In particular, the insertion portion 105 of the fixing member 10 shown in the enlarged circle of FIG. 1 is integrally formed with the lower plate portion 103 of the fixing member 10 and formed on the upper plate portion 101 of the fixing member 10. By being inserted into the hole 1011 can be detachably connected. Since the upper plate portion 101 of the fixing member 10 is flexible, it can be detachably connected to the insertion portion 105 of the fixing member 10 while moving in the direction of the arrow. The fastening form of such fixing member 10 is only for illustrating the present invention, and the present invention is not limited thereto. Therefore, the fixing member 10 can be fastened and fixed in other forms.

Here, the length W _f of the fixing space S formed in the fixing member 10 is preferably larger than the sum W _o of the thicknesses of the plurality of optical sheets 72. The fixing member 10 is provided with a fixing space S that can be fixed while penetrating the plurality of optical sheets 72, and the plurality of optical sheets 72 are accommodated through the fixing space S. Since the length W _f of the fixed space S along the Z-axis direction, which is a direction intersecting with the plurality of optical sheets 72, is greater than the sum W _o of the thicknesses of the plurality of optical sheets 72, the difference As much free space as possible. Such a spare space can be efficiently used when the optical sheet 72 thermally expands due to heat generation of the light source 76. That is, when the optical sheet 72 undergoes heat expansion and thermal expansion, the optical sheet 72 is also thermally expanded in the Z-axis direction, so that the optical sheet 72 having an increased thickness can be sufficiently accommodated through the free space. This prevents the occurrence of wick in the optical sheet 72. In addition, the diameter of the insertion portion 105 may be formed smaller than the opening 721 formed in the optical sheet 72 so that the optical sheet 72 may flow more freely, thereby preventing erosion.

The optical sheet 72 is integrally fixed by the fixing member 10, and the fixing member 10 is fixed to the stepped portion 751 formed on the outer surface of the bottom chassis 75 to fix the optical sheet 72. do. The stepped portion 751 is formed on the outer surface of the bottom chassis 75 along the Y axis, which is the arrangement direction of the light source 76.

FIG. 2 is a perspective view illustrating a backlight assembly 70 according to a first embodiment of the present invention in which all internal components of the backlight assembly 70 illustrated in FIG. 1 are combined.

As shown in FIG. 2, since the fixing member 10 (shown by dotted lines) is covered by the mold frame 71 on the upper side in the Z-axis direction, and fixed by the bottom chassis 75 on the lower side in the Z-axis direction, The optical sheet 72 can be fixed firmly.

3 is a partial cross-sectional view taken along the line BB of FIG. 2 and illustrates an internal structure of the backlight assembly 70 according to the first embodiment of the present invention.

As shown in FIG. 3, the upper and lower portions of the fixing member 10 are fixed to the mold frame 71 and the bottom chassis 75, respectively. The mold frame 71 covers the edge of the bottom chassis 75 to fix the optical sheet 72. The mold frame 71 fixes the upper sheet portion of the fixing member 10 to the recess 711 formed inside the mold frame 71. Insert and secure 101). In addition, the fixing portion 107 of the fixing member 10 is formed integrally with the lower plate portion 103 under the lower plate portion 103 of the fixing member 10. The fixing member 10 is fixed by inserting and fixing the fixing unit 107 formed in the fixing member 10 into the opening 753 formed in the bottom chassis 75.

Since the fixing member 10 is firmly seated and supported on the bottom chassis 75 according to the above-described structure, the optical sheet 72 can be firmly fixed.

4 is a partial cross-sectional view of the backlight assembly 80 according to the second embodiment of the present invention, and shows the same portion as the interior of the backlight assembly 70 according to the first embodiment of the present invention shown in FIG. 3.

As shown in FIG. 4, the bottom chassis 85 is provided with a plurality of step portions 851 and 853 to seat and support the fixing member 10 and the diffusion plate 74. On the outer surface of the bottom chassis 85 shown in FIG. 4, a first stepped portion 851 is first formed to seat and support the fixing member 10, and a second stepped portion 853 is separately formed to form a diffuser plate ( Seat 74 and support. In this way, the optical sheet 72 and the diffusion plate 74 fixed by the fixing member 10 are separately fixed to increase the reliability of the support structure.

FIG. 5 is an exploded perspective view of a flat panel display device 100 having a backlight assembly 70 according to a first embodiment of the present invention, wherein the liquid crystal display panel 50 is coupled to the backlight assembly 70. 100).

Although the liquid crystal display panel 50 is shown as an example of a flat panel display panel in FIG. 5, this is merely to illustrate the present invention and the present invention is not limited thereto. Accordingly, other types of light receiving flat panel display panels may be used. The flat panel display 100 is manufactured by assembling the backlight assembly 70 while covering the liquid crystal display panel 50 positioned on the backlight assembly 70 with the top chassis 60.

The liquid crystal display panel assembly 40 includes a liquid crystal display panel 50, driver integrated circuit packages 43 and 44 connected to the liquid crystal display panel 50, and a printed circuit board 41 and 42. The driver IC package 43 or 44 may be a chip on film (COF) or a tape carrier package (TCP), and the printed circuit boards 41 and 42 may be a top chassis 60. I can store it in the side.

The liquid crystal display panel 50 includes a TFT substrate 51 composed of a plurality of TFTs (thin film transistors), a color filter substrate 53 positioned on the TFT substrate 51, and a liquid crystal (injected therebetween). Not shown). Polarizing plates are attached to the upper portion of the color filter substrate 53 and the lower portion of the TFT substrate 51 to polarize light passing through the liquid crystal display panel 50.

The TFT substrate 51 is a transparent glass substrate on which a matrix thin film transistor is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of transparent indium tin oxide (ITO) as a conductive material is formed.

When electrical signals are input from the printed circuit boards 41 and 42 to the gate lines and the data lines of the liquid crystal display panel 50 described above, electrical signals are input to the gate terminal and the source terminal of the TFT, and these electrical signals are input. According to the input of the TFT, the TFT is turned on or turned off so that an electrical signal necessary for pixel formation is output to the drain terminal.

On the other hand, the color filter substrate 53 is disposed thereon opposite the TFT substrate 51. The color filter substrate 53 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, and a common electrode made of ITO is coated on the entire surface thereof. When power is applied to the gate terminal and the source terminal of the TFT and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate. By this electric field, the arrangement angle of the liquid crystal injected between the TFT substrate 51 and the color filter substrate 53 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

The printed circuit boards 41 and 42 for receiving the image signals from the outside of the liquid crystal display panel 50 and applying the driving signals to the gate lines and the data lines, respectively, are mounted on the respective driving IC packages attached to the liquid crystal display panel 50. (43, 44). In order to drive the flat panel display device 100, the gate side printed circuit board 41 generates a gate driving signal, and the data side printed circuit board 42 generates a data driving signal. Each driving IC package having the integrated circuit chips 431 and 441 mounted thereon by generating a gate driving signal, a data driving signal, and a plurality of driving signals for applying these signals at an appropriate time. The gate lines and the data lines of the liquid crystal display panel 50 are applied to the gate lines 43 and 44. A control board (not shown) is installed on the back of the backlight assembly 70. The control board is connected to the data side printed circuit board 42 to convert an analog data signal into a digital data signal and then supplies the same to the liquid crystal display panel 50.

The top chassis for preventing the liquid crystal display panel assembly 40 from being separated from the backlight assembly 70 while bending the driving IC packages 43 and 44 to the side of the backlight assembly 70 may be disposed on the liquid crystal display panel assembly 40. 60). Although not shown in FIG. 1, the front case and the rear case are positioned at the top of the top chassis 60 and the bottom of the bottom chassis 75, respectively, to form the flat panel display device 100 by combining them.

In the case of the flat panel display 100 assembled as described above, since the optical sheet 72 is firmly fixed, even when light is emitted from the backlight assembly 70, no light is generated in the optical sheet 72 so that the luminance of the light is maintained. The image can be improved, and a clear image can be displayed.

In the backlight assembly according to the present invention, since the length of the fixing space formed in the fixing member is larger than the sum of the thicknesses of the plurality of optical sheets, a space is secured to prevent light from being emitted from the light source and thermal expansion of the optical sheet. can do. The use of such a fixing member shortens the assembly time of the backlight assembly, thereby simplifying the assembly process and improving the assemblability.

Since the fixing member is seated and supported on the stepped portion formed on the outer surface of the bottom chassis, the optical sheet can be firmly fixed.

The diffusion plate may be positioned between the light source and the optical sheet to diffuse the light emitted from the light source to improve the uniformity of the light and then supply the light to the optical sheet.                     

Since the diffusion plate is seated and supported between the fixing member and the bottom chassis, it can be firmly fixed.

Since the diffuser plate is seated and supported on another stepped portion formed on the outer surface of the bottom chassis, the optical sheet may be spaced apart from the optical sheet, thereby allowing a firm fixing.

Since the insertion portion of the fixing member for fixing the optical sheet is connected with the upper plate portion and the lower plate portion of the fixing member, the structure of the fixing member for fixing the optical sheet has a solid advantage.

Since the insertion portion of the fixing member is detachably connected to the hole formed in the upper plate portion of the fixing member, the fastening structure of the fixing member is firm and there is no possibility that the optical sheet can be taken out even when the backlight assembly is impacted or vibrated.

Since the fixing portion of the fixing member is inserted and fixed in the opening formed in the bottom chassis, the fastening structure has a strong advantage.

Since the upper plate portion of the fixing member is inserted and fixed to the recess formed inside the mold frame, the optical sheet fixed by the fixing member can be firmly fixed.

Since the light source is composed of a plurality of lamps arranged spaced apart from each other along the width direction, it is possible to supply a large amount of light to implement a clear image.

Since the flat panel display device according to the present invention includes the above-described backlight assembly, there is an advantage that the assemblability is improved.

Since a liquid crystal display panel can be used as the flat panel display panel, there is an advantage that the application possibility is excellent.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations are possible without departing from the spirit and scope of the claims set out below.

Claims (12)

A light source for emitting light, A plurality of optical sheets for improving the brightness of light emitted from the light source, and A fixing member integrally fixing the plurality of optical sheets through an opening formed at edges of the plurality of optical sheets Including, The fixing member forms a fixing space for fixing the plurality of optical sheets, and the length of the fixing space along a direction crossing the plurality of optical sheets is greater than the sum of the thicknesses of the plurality of optical sheets. backlight assembly). In claim 1, And a bottom chassis accommodating the light source and the optical sheet, wherein the fixing member is seated and supported by a stepped portion formed on an outer surface of the bottom chassis along an arrangement direction of the light source. In claim 2, And a diffuser plate positioned between the light source and the optical sheet to diffuse light emitted from the light source. In claim 3, The diffuser plate is seated and supported between the fixing member and the bottom chassis. In claim 3, And another step portion formed on an outer surface of the bottom chassis, in addition to the step portion formed on the outer surface of the bottom chassis, and the diffusion plate seated and supported on the another step portion. In claim 1, The fixing member is provided with an insertion portion for fixing the optical sheet through the opening, the insertion portion of the fixing member is connected to the upper plate and the lower plate of the fixing member. In claim 6, The insertion member of the fixing member is integrally formed and connected to the lower plate portion of the fixing member, the backlight assembly is connected to the hole formed in the upper plate portion of the fixing member detachably. In claim 6, And a fixing part integrally formed with the lower plate portion under the lower plate portion of the fixing member is inserted into and fixed to an opening formed in the bottom chassis. In claim 6, And a mold frame covering the edge of the bottom chassis to fix the optical sheet, wherein the upper plate portion of the fixing member is inserted into and fixed to a recess formed in the mold frame. In claim 1, The light source is a backlight assembly consisting of a plurality of lamps arranged spaced apart from each other along the width direction. A flat panel display panel displaying an image, and The backlight assembly according to any one of claims 1 to 10, which supplies light to the flat panel display panel. Flat display device comprising a. In claim 11, And the flat panel display panel is a liquid crystal display panel.

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