KR100576121B1 - Backlight assembly - Google Patents

Abstract

The optical sheets are fabricated by integrally forming the cutter for the fixing protrusion and the cutter for the anti-flow groove to form the flow preventing hole from the center of the fixing protrusion of the optical sheets to one side of the fixing protrusion in the width direction or the longitudinal direction of the optical sheets. By cutting from the edge, the phenomenon in which the edge of the fixing protrusion is rolled into the cutter for the flow preventing groove can be prevented, thereby minimizing the manufacturing defect of the optical sheet.

 In addition, since the wear level of the blade of the side cutter and the blade of the flow preventing groove cutter are the same, the maintenance cost of the cutting die is reduced.

In addition, since the flow preventing grooves are completely punched at once, there is no need for a rework process for removing the residues present around the flow preventing grooves, thereby improving workability and productivity.

Frame, fixing groove, anti-flow boss, optical sheet, fixing protrusion, anti-flow groove, cutting mold

Description

Backlight assembly

1 is a plan view showing a structure in which a frame and optical sheets are combined in a conventional backlight assembly.

Figure 2 is a perspective view of a conventional cutting mold.

3 is a perspective view showing a structure of a backlight assembly and an optical sheet according to an embodiment of the present invention.

4 is a perspective view showing a cutting mold according to the present invention.

5 is a perspective view showing the structure of an optical sheet according to another embodiment of the present invention.

Figure 6 is a perspective view showing the structure of an optical sheet according to another embodiment of the present invention.

The present invention relates to a liquid crystal display, and more particularly, to improve the fixing means of the optical sheets to improve the brightness of the light to reduce the manufacturing defects of the optical sheets and to prevent the optical sheets from being separated from the frame during the assembly process It is about assembly.

Cathode ray tube (CRT), which is one of the commonly used display devices, is mainly used for monitors such as televisions, measuring devices, information terminal devices, etc., but due to its own weight and size, It could not actively respond to the demand for miniaturization and weight reduction.

In order to replace the cathode ray tube, it has advantages such as small size, light weight, low power consumption, and the like, and a liquid crystal display device that displays information by using the electrical and optical properties of the liquid crystal injected into the LCD panel has been actively developed. The function has been improved enough to perform a role as a flat panel display device, and is used as a monitor and a large liquid crystal display device of a desktop computer as well as a laptop computer.

Unlike the cathode ray tube, such a liquid crystal display device is not a light emitting material that can generate light, but a liquid crystal material injected between the TFT substrate and the color filter substrate. A separate light source, that is, a backlight assembly, for irradiating light to the LCD panel is essential.

The backlight assembly is installed on the frame in which the storage space is formed, the bottom chassis fastened to the lower surface of the frame, and the reflective sheet, the light guide plate, the optical sheets, and the light guide plate, which are installed on the base surface of the storage space to transmit light to the LCD panel. The lamp unit, which emits light, is configured as a top chassis covering the side of the frame from a predetermined portion of the edge of the LCD panel installed on the top of the frame.

Since the performance of the backlight assembly configured as described above greatly affects the display quality of the liquid crystal display device, it is important to minimize the assembly tolerance and the flow of the components between the members considering the thermal expansion coefficient, thereby improving the reliability of the backlight assembly.

Here, when the assembly tolerance between the frame and the light guide plate is smaller than the thermal expansion of the light guide plate, the light guide plate is bent in a predetermined direction by the frame, and in the case of the optical sheets, the light is generated to degrade the image quality of the liquid crystal display device.

Then, when the optical sheets are not fixed to the frame properly and the optical sheets flow, scratches occur due to friction between the optical sheets.

Accordingly, as shown in FIG. 1, a rectangular fixing groove 20 is formed at a predetermined portion of the short side of the frame 10 to the outside of the storage space, and the optical sheets 50 flow in the fixing groove 20. Form a flow preventing boss 25 to prevent.

Short edges of the optical sheets 50 fixed to the frame 10 configured as described above are formed to have a rectangular fixing protrusion 60 protruding by a predetermined length corresponding to the fixing groove 20, and prevent flow of the fixing protrusion 60. A flow preventing hole 65 is formed in a portion corresponding to the boss 25 and fixed to the frame 10 so that the optical sheets 50 do not flow.

Here, the diameter of the anti-flow hole 65 formed in the optical sheets 50 is formed larger than the diameter of the anti-flow boss 25 so that thermal expansion and contraction of the optical sheets 50 are free.

Such optical sheets 50 are formed by cutting from a large fabric by the cutting mold 70 shown in FIG. The cutting mold 70 has a rectangular side cutter 80 formed on the lower surface of the body 75 facing the fabric so as to correspond to the size of the optical sheets 50, and a predetermined portion of the short side of the side cutter 80. The fixing projection cutter 90 for forming the fixing projection 60 on the optical sheet 50 is formed extending to a predetermined length.

In addition, a flow preventing hole cutter 95 is installed at a central portion of the fixing protrusion cutter 90 to drill a circular hole in a portion where the fixing protrusion 65 is to be formed while the side cutter 80 cuts the fabric. The cutting mold 70 cuts optical sheets 50 having a shape as shown in FIG. 1 from the original fabric.

However, due to light weight, thinning, and miniaturization of the liquid crystal display device, the remaining area (non-screen display area) except for the screen display area is continuously reduced, so that the fixed groove 20 is formed as shown in FIG. The width of the rib 13 portion is narrowing.

Accordingly, the size of the fixing grooves formed in the rib portion of the frame and the size of the fixing protrusions accommodated in the fixing grooves are also reduced, so that the interval from the edge of the fixing protrusion to the insertion hole is narrow.

As a result, when the anti-flow hole is formed on the fixing protrusion of the optical sheet, the edge portion of the fixing protrusion is rolled into the cutter for the anti-flow hole, so that the anti-flow hole is not punched smoothly, resulting in a defect of the optical sheet.

In addition, the blade of the flow preventing hole cutter is faster to wear than the blade of the side cutter, and when punching, the unnecessary parts are not cut off completely, but the parts are attached to the optical sheet, so that workers cut the optical sheets from the fabric, Workability and productivity are reduced because a rework process is performed to remove the residue adhering to the surroundings.

In addition, as described above, since the blade of the flow preventing hole cutter is more severe than the blade of the side cutter, there is a problem in that the punch needs to be replaced frequently.

Accordingly, an object of the present invention is to conceive in view of the above problems, by modifying the cutter for fixing projections of the cutting mold to enable the optical sheets to be cut smoothly from the fabric to minimize the manufacturing defects of the optical sheets and workability And to improve productivity.

Another object of the present invention is to extend the punch replacement cycle in accordance with the wear rate of the punch forming the insertion hole and the wear rate of the optical sheet cutter for cutting the optical sheet.

Still other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

In order to achieve the above object, the present invention provides fixing bosses on the sidewalls facing each other in the storage space of the frame to the outside of the storage space, and anti-flow bosses for restricting the flow of the optical sheets in predetermined portions of the fixing grooves It protrudes to a predetermined height, and the fixing projections received in the fixing grooves in a portion corresponding to the fixing grooves in the optical sheet that is fixed to the frame to improve the brightness of the light extending to a predetermined length, and corresponding to the flow preventing boss From the predetermined portion of the fixing projections to form a flow preventing grooves extending along one side of the fixing projections along the side of the optical sheet on which the fixing projections are formed and inserted into the flow preventing groove.

For example, the fixing protrusions are formed at a short side of the optical sheet, and the flow preventing grooves extend from one portion corresponding to the preventing bosses to one side of the fixing protrusion along the width direction of the optical sheet so that one side of the flow preventing grooves is formed. Opening.

Preferably, the width of the flow preventing groove is equally formed from a portion corresponding to the flow preventing boss to one side of the fixing protrusion along the side surface on which the fixing protrusions are formed.

In addition, the flow preventing groove is formed in a portion corresponding to the flow preventing boss is formed in the seating portion to which the flow preventing boss is fitted, and extends from the seating portion to one side of the fixing protrusions along the side wall of the optical sheets on which the fixing protrusions are formed. The width of the prevention bosses is formed to be smaller than the flow prevention boss is configured to prevent the departure from the seating portion.

Hereinafter, the structure of the backlight assembly of the liquid crystal display according to the present invention will be described with reference to FIGS. 2 to 6.

The liquid crystal display device is largely composed of a display unit displaying information by the electrical and optical properties of the liquid crystal, and a backlight assembly 100 supporting the display unit and transmitting light to the display unit.

The backlight assembly includes a frame 110 having a rectangular accommodating space 115 formed therethrough from an upper surface to a lower surface, and a bottom chassis fastened to the lower surface of the frame 110 to close the lower surface of the frame 110. (Not shown), a reflector (not shown) installed on the bottom surface of the bottom chassis to reflect light, a light guide plate 130 installed on the top of the reflector to guide the light to the display unit, and installed on the side of the light guide plate 130 to emit light. It includes a lamp unit (not shown) that emits and the optical sheets 150 installed on the upper surface of the light guide plate 130 to improve the efficiency of the light transmitted from the light guide plate 130.

As shown in FIG. 3, the storage space 115 of the frame 110 is divided into two regions by a step. In the lower storage space adjacent to the bottom chassis, a reflecting plate, a light guide plate 130, and a lamp unit are installed. The optical sheets 150 are installed in the upper accommodating space 115 adjacent to the unit.

Fixing grooves 120 and flow preventing bosses for preventing the flow of the optical sheets 150 as shown in FIG. 3 at both short sides of the upper receiving space 115 in which the optical sheets 150 are installed. 125) is formed.

The fixing grooves 120 are formed in a quadrangular shape having a predetermined size at both ends of the short sides of the upper storage space 115, and ribs of the frame 110 formed on the outer side of the upper storage space 115 from the upper storage space 115. Toward the 113 side.

In addition, the flow preventing bosses 125 are formed to protrude to a predetermined height from the center portion of each receiving groove 150, thereby limiting the flow of the optical sheets 150.

Meanwhile, the optical sheets 150 inserted into the fixing grooves 120 and the flow preventing bosses 125 and fixed to the frame 110 are optical sheets 150 as shown in FIGS. 3, 5, and 6. The fixing protrusions 160 are formed to extend by a predetermined length in a portion corresponding to the fixing grooves 120 of the short sides of the), and the central portion of each of the fixing protrusions 160 is fitted to the flow preventing bosses 125. Prevention grooves 165 are formed.

The flow preventing groove 165 extends from the center of the fixing protrusion 160 to one side of the fixing protrusion 160 along the width direction of the optical sheet 150, and the fixing protrusion 160 having the flow preventing groove 165 formed therein. One side of the) is opened and prevents the left and right flow of the optical sheets 150 in FIG. 3, while preventing the optical sheets 150 from being separated from the frame 110 when assembling the liquid crystal display.

The flow preventing groove 165 according to the exemplary embodiment has the same width from the center of the fixing protrusion 160 to one side of the fixing protrusion 160 along the width direction of the optical sheet 150 as shown in FIG. 3. do.

As shown in FIG. 5, the flow preventing groove 165 according to another embodiment includes a seating portion 167 on which the flow preventing boss 125 is seated, and a flow preventing boss 125 seated on the seating portion 167. It is composed of a departure prevention portion 169 to prevent falling into the opened portion of the flow preventing groove 165.

Here, the seating portion 167 is formed in the central portion of the fixing protrusion 160 corresponding to the flow preventing boss 125, the departure preventing portion 169 is the width direction of the optical sheet 150 from the seating portion 167. It is formed to extend to one side of the fixing protrusion 165, to prevent the flow preventing boss 125 from falling out of the optical sheet 150 through the open portion of the flow preventing groove 165, the separation prevention unit 169 The width of) is smaller than the diameter of the flow preventing boss 125.

As shown in FIG. 6, the flow preventing groove 165 according to another embodiment includes a seating portion 167 on which the flow preventing boss 125 is seated, and a flow preventing boss 125 seated on the seating portion 167. Is prevented from falling into the open portion of the flow preventing groove 165 is composed of a departure preventing portion 169, the flow preventing groove 165 shown in Figure 6 is the flow preventing groove 165 shown in FIG. The difference between the mounting portion 167 is formed in the longitudinal direction of the optical sheet 150 in the fixing projections 160.

That is, the seating portion 167 shown in FIG. 5 is circular, and the seating portion 167 shown in FIG. 6 is oval long in a direction orthogonal to the departure preventing portion 169.

As shown in FIG. 6, the reason for forming the seating portion 167 in the long hole shape is limited by the flow preventing boss 125 when the optical sheets 150 are thermally expanded and contracted by the heat emitted from the lamp unit. In order to prevent the movement of the optical sheets 150 to the maximum by allowing free expansion and contraction.

The optical sheets 150 having the above-described structure are formed by cutting from a large fabric by the cutting mold 200 shown in FIG. 4.

The cutting mold 200 has a rectangular side cutter 210 formed along the edge of the lower surface of the body 205 facing the fabric so as to correspond to the size of the optical sheet 150 shown in FIG. Square fixing protrusions 220 are formed to extend a predetermined length from both ends of the short side of 150 to form fixing protrusions 160 on the optical sheet 150.

In addition, a predetermined portion of the side cutter 210 in the width direction end portion of the fixing protrusion cutter 220 is formed with a flow preventing groove cutter 225 for forming a flow preventing groove 165, the flow preventing groove cutter ( 225 is bent from a predetermined portion of one end of the fixing projection cutter 220 to the center of the fixing projection cutter 220, and then again from the central portion of the fixing projection cutter 220 one end of the fixing projection cutter 220 It is formed integrally with the fixing protrusion cutter 220 in a "∩" shape is formed to be bent to a predetermined portion.

The manufacturing method of the optical sheet and the assembling process of the backlight assembly are described as follows.

First, a method of forming the optical sheets 150 will be described. A fabric for forming the optical sheets 150, for example, a fabric for diffusing light, a fabric for condensing light, and protecting them Place any one of the fabric for the workbench (not shown) installed on the part opposite to the cutting mold (200).

Thereafter, when the cutting mold 200 is lowered toward the work table on which the fabric is placed, the side cutter 210 integrally formed on the lower surface of the body 205 cuts the edges of the optical sheets from the fabric, and the fixing protrusion cutter 220 ) Cuts the fixing protrusions 160 protruding from the short sides of the optical sheets 150 by a predetermined length from the original fabric, and the cutter for preventing flow grooves 225 cuts the fixing protrusions 260 in a "∩" shape. A flow preventing groove 165 is formed.

The edges of the optical sheets 150, the fixing protrusions 160, and the flow preventing grooves 165 are cut at once from the fabric to form the optical sheet 150 having the shape shown in FIG. 3, 5, or 6.

When the optical sheets 160 are manufactured as described above, the backlight assembly 100 is assembled. The light guide plate 130 is installed in the lower storage space 110 by inverting the frame 110 so that the lower storage space is upward. The lamp unit used as the light source of the liquid crystal display device is coupled to the longitudinal side of the light guide plate 130. Subsequently, the light guide plate 130 and the lower surface of the lamp unit are provided with a reflecting plate for reflecting light emitted from the lamp unit toward the light guide plate 130.

Subsequently, the bottom chassis is covered on the bottom surface of the frame 110 facing the reflector to fix the light guide plate 130, the lamp unit, and the reflector to the side of the frame 110.

When the frame 110 and the bottom chassis are coupled, the frame 110 is flipped again so that the upper accommodating space 115 is upward, and then the optical sheets 150 manufactured as described above are inserted into the frame 110.

That is, the fixing protrusion 160 of the optical sheets 150 and the fixing groove 120 of the frame 110 are aligned, the flow preventing groove 165 and the flow preventing boss 125 are aligned, and then the optical sheet. The optical sheet 150 is fixed to the frame 110 by lowering the 150 to the frame 110.

As such, when the flow preventing groove 165 is formed toward the width direction of the optical sheet 150 from the center of the fixing protrusion 165, the optical sheet 150 is prevented from flowing to the left and right (Ｘ axes). 165 and the flow preventing boss 125 prevents, and the fixing groove 120 and the fixing protrusions 160 to prevent the optical sheets 150 flow to the front and rear (Y-axis).

If the flow preventing groove 165 is formed along the longitudinal direction of the optical sheet 150 from the center of the fixing protrusion 160, it is incomplete to restrict the left and right (우 axis) flow of the optical sheets.

In addition, in the case of a backlight assembly in which an anti-flow boss is formed on a side facing the light guide plate of the upper accommodating space and the optical sheets, the light guide plate, and the reflecting plates are sequentially stacked in the lower accommodating space, the directions in which the display units are installed by the weight of the optical sheets. To this end, the anti-flow boss enters the opened portion of the anti-flow groove so that the optical sheets leave the frame.

For the reason described above, in the present invention, the flow preventing grooves 165 are formed along the width direction of the optical sheets 150.

As such, when the optical sheets 150 are fitted to the frame 110, the optical sheets 150 may be disposed on the fixing grooves 120 in order to prevent the optical sheets 150 from falling out in the direction in which the display unit is installed, that is, in the y-axis direction. Attach the adhesive tape 162 to close the fixing grooves 120.

Thereafter, a display unit is installed on the upper surfaces of the optical sheets 150, and the top chassis is covered on the upper surface of the display sheets to be combined with the frame.

As such, when the flow preventing grooves 165 are formed along the width direction of the optical sheet 150 from a portion corresponding to the flow preventing boss 125, management of the dimension tolerance is easy and precision is improved.

As described above, when the fixing protrusions 160 are formed at the short sides of the optical sheet 150, the anti-induction grooves 165 may be in the width direction of the optical sheet 150 from a portion corresponding to the anti-flow boss 125. Although formed along the other hand, when the fixing projections are formed on the long sides of the optical sheets, the flow preventing grooves extend from the portion corresponding to the flow preventing boss to one side of the fixing protrusions along the longitudinal direction of the optical sheet.

As described above, the present invention provides a cutter for fixing projections and a flow preventing groove to form a flow preventing hole from the center of the fixing projections of the optical sheets to one side of the fixing projection in the width direction or the longitudinal direction of the optical sheets. By forming the cutter integrally and cutting the optical sheets from the original fabric, the phenomenon that the edge of the fixing protrusion is rolled into the cutter for the flow prevention groove is prevented, thereby minimizing the manufacturing defect of the optical sheet.

 In addition, since the wear of the blade of the sight cutter and the blade of the flow preventing groove cutter is almost the same, the maintenance cost of the cutting die is reduced.

In addition, since the flow preventing grooves are completely punched at once, there is no need for a rework process for removing residues around the flow preventing grooves, thereby improving workability and productivity.

Claims (5)

A lamp for emitting light, a reflecting plate for reflecting light emitted from the lamp, a light guide plate installed on an upper surface of the reflecting plate and guiding light cut from the lamp and the reflecting plate toward an LCD panel, and an upper surface of the light guide plate Optical sheets which are installed in the light guide plate to increase the brightness of the light guided by the light guide plate and cut the LCD panel, and an accommodating space in which the lamp, the reflecting plate, the light guide plate, and the optical sheets are stored is formed, and a short side of the accommodation space is formed. In the backlight assembly comprising a frame is formed in the fixing grooves for fixing the optical sheets in the predetermined portion of the fixing grooves the anti-flow bosses for restricting the flow of the optical sheets protruding to a predetermined height,  A portion of the short side of the optical sheet corresponding to the fixing grooves is formed with fixing projections received in the fixing groove to extend a predetermined length, and the optical from the portion corresponding to the flow preventing boss of each of the fixing projections The backlight assembly, characterized in that the flow preventing grooves are formed to extend to one side of the fixing protrusion along the width direction of the sheet to open one side of the flow preventing grooves. The backlight assembly of claim 1, wherein a width of the flow preventing groove is equally formed from a portion corresponding to the flow preventing boss to one side of the fixing protrusion along a side surface on which the fixing protrusions are formed. The method of claim 1, wherein the flow preventing groove A seating portion formed at a portion corresponding to the flow preventing bosses to which the flow preventing boss is fitted; It extends from one side of the seating portion to one side of the fixing protrusions along the sidewalls of the optical sheets on which the fixing protrusions are formed, the width of which is smaller than the diameter of the flow preventing bosses are separated from the seating portion Backlight assembly, characterized in that consisting of the departure prevention portion to prevent. 4. The backlight assembly of claim 3, wherein the seating portion is circular and the diameter of the seating portion is slightly larger than the diameter of the flow preventing boss. 4. The backlight assembly of claim 3, wherein the seating portion has an elliptical length long in a direction crossing the departure preventing portion and is larger than a diameter of the flow preventing boss.

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