KR20040062208A - Back light assembly - Google Patents

Abstract

PURPOSE: A backlight assembly is provided to prevent folds generated in optical sheets due to weight of the optical sheets and force applied to fixing parts of a shaft. CONSTITUTION: A plurality of optical sheets(111) are accumulated on the back of a mold frame(100). A light guide plate and a reflecting plate are assembled with the mold frame and a lower cover is combined to cover the back of the mold frame. The plurality of optical sheets are fixedly combined with a shaft of the mold frame by forming two upper part support protrusions(110a,110b) at an upper part, and two lower part support protrusions(110c,110d) at a lower part. A plurality of fixing holes are formed at the support protrusions, different in shape.

Description

Backlight Assembly {BACK LIGHT ASSEMBLY}

The present invention relates to a backlight assembly, and more particularly, to a backlight assembly capable of preventing sagging and thermal deformation of optical sheets used in a backlight region of an LCD monitor used in a display device.

Recently, due to the rapid development of technology in the semiconductor industry, display devices are becoming smaller and lighter, and more powerful products are being produced. Cathode ray tubes (CRTs), which are widely used in information display devices, have many advantages in terms of performance and price, but have disadvantages in terms of miniaturization or portability. On the other hand, liquid crystal displays have been attracting attention as an alternative means of overcoming the shortcomings of CRT due to the advantages of miniaturization, light weight, and low power consumption, and are now used in almost all information processing devices that require display devices. It is the situation that is attached.

Such liquid crystal displays generally apply voltages to specific molecular arrays of liquid crystals, convert them into other molecular arrays, and change optical properties such as birefringence, photoreactivity, dichroism, and light scattering characteristics of liquid crystal cells that emit light by such molecular arrangements. Is a display using modulation of light by a liquid crystal cell.

The liquid crystal display is largely divided into twisted nematic (TN) and super-twisted nematic (STN) methods, and the active matrix display method using a switching element and TN liquid crystal and a passive matrix using STN liquid crystal due to the difference in driving method. passive matrix).

The big difference between these two methods is that the active matrix display method is used for TFT-LCD, which drives the LCD using the TFT as a switch, and the passive matrix display method does not use transistors, thus requiring a complicated circuit. Do not

Since the liquid crystal display is a passive optical device that does not emit light by itself, an image is displayed by using a backlight assembly attached to the rear surface of the liquid crystal panel.

Recently, various structures have been developed for slimming and lightening in order to secure the competitiveness of the product. In particular, in view of the fact that the liquid crystal display device is mainly used in portable computers and the like, weight reduction is treated more heavily.

In particular, the role and function of the backlight assembly have emerged as an important problem in the liquid crystal display device. Since the size and the light efficiency of the liquid crystal display device vary depending on the structure of the backlight assembly, the mechanical and optical characteristics of the overall liquid crystal display device are different. Because it is affected a lot.

The general structure of a liquid crystal display including a backlight assembly includes a liquid crystal panel, a backlight assembly, and a mold frame, and the backlight assembly includes a lamp unit and a light guide unit.

The lamp unit includes a lamp for generating light and a lamp housing surrounding the lamp. On the other hand, the light guide unit is generally composed of a reflecting plate, a light guide plate, a diffusion sheet, a light collecting sheet and a protective sheet, the diffusion sheet, the light collecting sheet and the protective sheet is called an optical sheet.

The light guide plate is formed of a panel of a plastic-based transparent material such as acrylic to propagate light generated from the lamp toward a liquid crystal panel seated on the light guide plate.

Accordingly, various patterns for converting a traveling direction of light incident into the light guide plate toward the liquid crystal panel are printed on the rear surface of the light guide plate. The reflective plate is positioned on the lower surface of the light guide plate, and reflects the light not reflected by the minute dot pattern on the back surface of the light guide plate toward the exit surface of the light guide plate, thereby reducing the optical loss of the light incident on the liquid crystal panel and at the same time. It serves to improve the uniformity of the light transmitted to the exit surface of the.

A diffusion sheet located between the light guide plate and the light collecting sheet prevents light from being partially concentrated by dispersing light incident from the light guide plate. The light collecting sheet has a triangular prism-shaped prism formed on a top surface thereof, and is generally composed of two sheets, and each prism array is arranged to be staggered at a predetermined angle to each other to receive light diffused from the diffusion sheet. It serves to condense in a direction perpendicular to the liquid crystal panel.

As a result, the light passing through the light collecting sheet almost vertically proceeds, so that the luminance distribution on the protective sheet is uniformly obtained. The protective sheet formed on the light collecting sheet not only serves to protect the surface of the light collecting sheet, but also serves to diffuse light in order to uniformize light distribution.

The liquid crystal panel is mounted on the protective sheet and seated in the mold frame together with the backlight assembly. The mold frame accommodates and fixes the backlight assembly and the liquid crystal panel, and prevents the backlight assembly including the plurality of sheets from being bent, and a plurality of support parts forming a portion where the printed circuit board of the liquid crystal panel contacts. Formed.

1 is a view schematically illustrating an assembly structure of a liquid crystal display according to the related art.

As shown in FIG. 1, the liquid crystal display includes a liquid crystal panel 5 for displaying an image by applying an image signal, a backlight assembly 10 for supplying light, a liquid crystal panel 5, and a backlight assembly 10. It consists of a mold frame (21) for fixing the upper case (1) and the lower cover (22) for storing them.

The liquid crystal panel 5 has a structure in which a driving signal of the liquid crystal display device is connected to the gate PCB 7 which is applied from the outside, and a data PCB 9 is connected in order to receive the graphic signal from the outside.

In the liquid crystal panel 5, the arrangement angle of the liquid crystal injected by the applied power is changed and the light transmittance generated from the backlight assembly 10 is changed according to the changed arrangement angle to obtain a desired image.

As shown, a backlight assembly 10 is provided below the liquid crystal panel 5 to provide uniform light to the liquid crystal panel 5.

The backlight assembly 10 includes a lamp 13 for generating light and a lamp housing (not shown) surrounding the lamp 13.

A cold cathode tube is generally used as the lamp 13, and the light generated by the lamp 13 is incident on the light guide plate 15. The lamp housing reflects the light generated from the lamp 13 toward the light guide plate 15.

The light guide plate 15 has a size corresponding to that of the liquid crystal panel 5 and is located below the liquid crystal panel 5 and is thicker in an area closer to the lamp 13 and farther from the lamp 13. It is formed to have a thin thickness to guide the light generated by the lamp 13 toward the liquid crystal panel 5 to change the path of the light.

A plurality of optical sheets 11 are provided on the light guide plate 15 to uniform the luminance of light emitted from the light guide plate 15 and directed toward the liquid crystal panel 5. The plurality of optical sheets 11 are fixed to the mold frame 21 at upper and lower portions integrally at both side ends in the longitudinal direction, respectively.

In addition, the reflector 17 is provided below the light guide plate 15 to increase the efficiency of light by reflecting light leaked from the light guide plate 15 back to the light guide plate 15.

The liquid crystal panel 5 and the backlight assembly 10 are laminated and inserted into the mold frame 21 to be fixedly supported. The mold frame 21 has a box shape of a rectangular parallelepiped and an upper surface thereof is opened. The mold frame 21 supports four sidewalls and a bottom surface, and supports the backlight assembly 10 and the liquid crystal panel 5, except for the lamp 13 insertion portion. The liquid crystal panel 5 and the backlight assembly 10 are installed inside the mold frame 21.

On the upper surface of both ends of the mold frame 21 in the vertical direction, a locking jaw protruding further from the light collecting sheet in the direction of the liquid crystal panel 5 is formed, and the locking jaw is separated from the positions of the optical sheets 11. It also serves to prevent flow.

After installing the backlight assembly 10 and the liquid crystal panel 5 to the mold frame 21, the upper surface part 1 is opened to expose the liquid crystal panel 5 so as to be integrally fixed. The lower cover 22 is coupled to the lower side to fix the backlight assembly 10 while supporting the backlight assembly 10.

2 is a view showing the assembly structure of the optical sheets of the backlight assembly according to the prior art.

Referring to FIG. 2, the mold frame 21 is inserted with a lamp (not shown) which is used as a light source of the liquid crystal display in a horizontal direction, and the lamp includes the optical sheets along edge edges of the mold frame. Will be placed side by side.

In addition, the optical sheets 11 are sequentially stacked on the inner side of the mold frame 21, and a backlight assembly such as a light guide plate, a reflecting plate, and the like is disposed on an inner surface of the optical sheets 11.

The optical sheets have the protrusions 32a and 32b formed at left and right edges, and the protrusions formed on the upper side in the horizontal direction of the optical sheet are the upper protrusions 32a and the lower protrusions formed on the lower side. 32b), and fixed to the mold frame 21 by adhesive tape 31 at edges of the mold frame 21, respectively.

As the adhesive tape 31, a sheet / pet tape is generally used.

Meanwhile, an upper surface of the mold frame 21 side end portion between the upper protrusion 32a and the lower protrusion 32b has a shape more protruding toward the liquid crystal panel than the optical sheets 11. Is formed.

3 is an enlarged plan view of the area A of FIG. 2, and referring to FIG. 3, the locking jaw 35 is a distance between a lower side of the upper protrusion 32a and an upper side of the lower protrusion 32b. It has a length corresponding to and has an arbitrary width on the upper surface of the side end of the mold frame 21.

In addition, the optical protrusions 11 are attached to the locking projections 35 formed on the mold frame 21, and the upper protrusions 32a and the lower protrusions 32b are formed by the adhesive tape 31. It is bonded to the mold frame 21.

That is, the latching jaw 35 serves as a guide of the optical sheets 11 and the optical sheets 11 into the mold frame 21 by the protrusions 32a and 32b. It will be supported by both sides to avoid this sag.

4 is a cross-sectional view of the B-B 'region of FIG. 2 vertically cut. Referring to FIG. 4, a plurality of optical sheets 11 are inserted into the latching jaw 35 of the mold frame 21. The optical sheets 11 are fixed to the mold frame 21 by an adhesive tape 31.

The locking jaw 35 formed on the mold frame 21 serves as a guide of the optical sheets 11, and a lower portion of the optical sheets 11 fixed to the locking jaw 35. The light guide plate 15 and the reflecting plate 17 are arranged in this.

By forming a friction surface with the sides of the optical sheets 11 and the adhesive tape 31, it is possible to resist the electrostatic attraction formed between the liquid crystal panel and the surface of the optical sheet 11.

However, in the backlight assembly according to the related art, the horizontal length and the vertical length of the optical sheet are considerably large in the case of the LCD monitor which is being enlarged.

That is, in the case of the optical sheet of a small area, there is no big problem, but in the case of the enlarged optical sheet, the phenomenon of deflection occurs in the center portion.

5 is a view showing a deflection phenomenon of the optical sheet of the backlight assembly according to the prior art.

As shown in FIG. 5, there is a problem in which wrinkles occur in the optical sheet in which deflection occurs in a downward direction under load from both sides fixed around a vertical axis of the optical sheet.

That is, the rotational moment is generated because the load direction of the optical sheet and the direction of the force of the fixed shaft do not coincide, and thus a morning glory wrinkle occurs.

This causes a blot-like image on the displayed LCD monitor.

The present invention is to provide a good quality image by preventing the wrinkles caused by the fixing force and the load of the optical sheet by the left and right fixed axis, or the upper and lower fixed axis of the optical sheet of the backlight assembly used for a large LCD monitor, etc. The purpose is to provide an assembly.

1 is a view schematically showing an assembly structure of a liquid crystal display device according to the prior art.

2 is a view showing the assembly structure of the optical sheets of the backlight assembly according to the prior art.

3 is an enlarged plan view of region A of FIG. 2;

4 is a cross-sectional view taken along the line BB ′ of FIG. 2;

5 is a view showing sagging of the optical sheet of the backlight assembly according to the prior art.

6 is a view showing the assembly structure of the optical sheet of the backlight assembly according to the present invention.

7 is an enlarged plan view of a region C and a region D of FIG. 6;

8 and 9 illustrate an optical sheet of a backlight assembly according to other embodiments of the present invention.

* Description of the symbols for the main parts of the drawings *

100: mold frame 110a, 110b: upper support protrusion

110c, 110d: Lower support protrusion 111: Optical sheet

130: shaft

In order to achieve the above object, the backlight assembly according to the present invention,

In the backlight assembly consisting of a backlight, a reflecting plate, a light guide plate, and optical sheets coupled to the inside of the mold frame on which the liquid crystal panel is seated on the upper side,

The optical sheet is characterized in that it is coupled to the shaft formed on the mold frame, having the support protrusions in the horizontal direction.

Here, the upper and lower support protrusions each have two support protrusions in the horizontal direction of the optical sheet, and the upper two support protrusions and the lower two support protrusions are formed with fixing holes having different shapes, respectively, which are formed in the optical sheet. The support protrusions are coupled to each other while having a coupling margin up, down, left and right.

In particular, the optical sheet is fixed to the mold frame is characterized in that coupled to distribute the force parallel to the upper side and the lower side in the horizontal direction.

In addition, the backlight assembly according to another embodiment of the present invention,

In the backlight assembly consisting of a backlight, a reflecting plate, a light guide plate, and optical sheets coupled to the inside of the mold frame on which the liquid crystal panel is seated on the upper side,

The optical sheet may be coupled to a shaft formed on the mold frame while having two up and down support protrusions in a horizontal direction and support protrusions on left and right sides in a vertical direction.

Here, the number of the support protrusions formed on the left and right sides in the longitudinal direction of the optical sheet is one or a plurality, respectively, the support protrusions formed on the optical sheet are coupled to have a coupling margin up, down, left and right, and fixed to the mold frame The optical sheet to be coupled is characterized in that the force parallel to the upper and lower sides in the horizontal direction, the left and right sides in the vertical direction is distributed.

According to the present invention, in order to balance the force generated left and right or up and down on the support projections of the optical sheets inside the LCD used in the large monitor, two support projections are provided on the upper and lower support projections, and fixing holes of different sizes are respectively provided. The formation prevented the occurrence of wrinkles in the optical sheet.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

6 is a view showing the assembly structure of the optical sheet of the backlight assembly according to the present invention.

Referring to FIG. 6, the backlight assemblies are sequentially stacked and inserted into the rear surface of the mold frame 100, and the optical sheets 111 are stacked on the rear surface of the mold frame 100.

That is, a plurality of optical sheets 111 are first stacked in a front direction in which a liquid crystal panel is seated on an inner space of the mold frame 100, and then light guide plates and reflective plates are assembled, and finally a lower cover is coupled to the mold. The back surface of the frame 100 is covered.

In addition, a lamp (not shown) is inserted along an edge edge of the mold frame 100, and the lamp propagates light into the light guide plate to generate plane light, and then passes through the optical sheets 111. Next, the liquid crystal panel is reached.

The optical sheets 111 are formed of thin sheets having a rectangular shape. As the size of the liquid crystal panel increases, the optical sheets 111 do not sag, and upper and lower edge edges thereof may be assembled to the mold frame. Along the fixing portion along, and coupled to the shaft of the mold frame 100.

Conventionally, the left and right sides of the mold frame are coupled to each other or adhered by a tape. However, the present invention has two rectangular upper support protrusions 110a and 110b) because the optical sheet has a rectangular structure. Two lower support protrusions 110c and 110d at the bottom were fixed to the shaft of the mold frame 100.

Fixing holes are formed in the support protrusions 110a, 110b, 110c, and 110d formed in the optical sheets 111, and holes of different shapes are formed for right and left and top and bottom coupling margins with the mold frame 100. It was.

That is, any one of the fixing holes of the upper support protrusions 110a and 110b formed on the optical sheets 111 above the left and right coupling margins has a circular shape such that it does not move by coupling with the shaft. Fixed hole, the other (110b) formed an elliptical fixing hole to be moved by a constant coupling margin by coupling with the shaft.

Therefore, when the optical sheets 111 are coupled to the shaft of the mold frame 100 by two support protrusions 110a and 110b on the top and two support protrusions 110c and 110d on the bottom, the optical sheets Since the direction sag due to the weight of 111 and the direction of the reaction force coincide on the same line, the force acts evenly over the entire area of the optical sheet, so that wrinkles due to sag are not formed.

FIG. 7 is an enlarged plan view of region C and region D of FIG. 6.

As shown in FIG. 7, the support protrusions 110a, 110b, 110c, 110d of the optical sheets 111 are coupled to the shaft 130 on the mold frame 100, and the upper support protrusion 110a is provided. The left side of the mold frame 100 is fixed integrally with the shaft 130, the right side of the upper support protrusion (110b) is formed with an elliptical fixing hole having a fixed margin is formed so that the optical sheets 111 to the left and right sides It was allowed to combine with a certain margin.

In the case of a large LCD monitor, a large amount of heat is generated, and thus, the optical sheets are subjected to a change in bonding due to temperature. .

In addition, the coupling margins of the support protrusions 110c and 110d formed on the lower side of the optical sheets 111 also have a fixing hole having a slightly larger diameter, thereby providing left and right coupling margins.

In addition, margins of upper and lower fixing parts of the optical sheets 110a, 110b, 110c, and 110d are also provided to optimally couple the mold frame 100 and the optical sheets 111.

8 and 9 illustrate an optical sheet of a backlight assembly according to other embodiments of the present invention. As shown in FIG. 8, the structure of the optical sheets 222 inserted into the mold frame 100 is illustrated. Two support protrusions 210a, 210b, 210d and 210c were placed on the upper side and the lower side, respectively, and one support protrusion 210c and 210f was placed on the left and right sides, respectively.

The upper support protrusions 210a and 210b and the lower support protrusions 210c and 210d of the optical sheets are coupled to a shaft formed on the upper and lower sides of the mold frame 100, and the mold frame 100 is coupled to the shaft. ), The left support protrusion 210e and the right support protrusion 210f of the optical sheet 222 are fixed to the shafts formed on the left and right sides thereof.

The upper and lower support protrusions 210a, 210b, 210c, and 210d of the optical sheets 222 have a fixing force fixed to the shaft about the load and the axis of the optical sheet 222 by 180 ° on the same line. Since the structure is such that only the force in the up and down directions is exerted over the entire area of the optical sheet, sheet deflection does not occur.

In addition, as the size of the large LCD optical sheet increases, sagging of the left and right edge portions may occur, and the sagging may be prevented by fixing the left and right support protrusions 210e and 210f. Sheet deflection does not occur in parallel planes.

As shown in FIG. 9, two or more support protrusions 310a, 310b, 310c, 310d, 320a, and 320b are disposed on the optical sheet 333, respectively, and a fixing hole for coupling margin is formed. Two support protrusions 320a and 320b are formed on the left and right sides to prevent the sheet from sagging along the vertical axis of the optical sheet 333.

In addition, the upper support protrusions 310a and 310 and the lower support protrusions 310 and 310 formed on the upper side and the lower side of the optical sheet 333 together with the left and right support protrusions 320a and 320b in the sheet load direction. It serves to prevent the deflection phenomenon, and the sheet deflection does not occur because it is fixed with a predetermined magnitude of force on all corners along the optical sheet circumference.

In addition, since fixing holes are formed on the left and right support protrusions 320a and 320b as well as the upper and lower support protrusions 310a, 310b, 310c, and 310d, coupling failures due to heat generated in the large LCD are prevented.

In addition, the combination of the optical sheet is improved because the alignment of the optical sheets and the light guide plate, the liquid crystal panel is laminated, there is an advantage that can improve the image quality of the displayed LCD monitor.

As described in detail above, the present invention acts on the load of the sheet and the fixing portion of the shaft by arranging the supporting projections of the optical sheets inside the LCD used in the large monitor in the upper and lower sides or the upper and lower sides and the left and right sides of the sheet, respectively. It is effective in preventing wrinkles from occurring due to the force.

In addition, the shrinkage / expansion caused by heat provided a fixed margin to prevent wrinkles in the optical sheet.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Claims (9)

In the backlight assembly consisting of a backlight, a reflecting plate, a light guide plate, and optical sheets coupled to the inside of the mold frame on which the liquid crystal panel is seated on the upper side, And the optical sheet has upper and lower support protrusions in a horizontal direction, and is coupled to a shaft formed on the mold frame. The method of claim 1, Backlight assembly characterized in that it has two support projections each up and down in the horizontal direction of the optical sheet. The method according to claim 1 or 2, And the upper two support protrusions and the lower two support protrusions are formed with fixing holes having different shapes. The method of claim 1, The support protrusions formed on the optical sheet are coupled while having a coupling margin up, down, left and right. The method of claim 1, The optical sheet is fixed to the mold frame is a backlight assembly, characterized in that coupled to distribute the parallel parallel to the upper and lower side in the horizontal direction. In the backlight assembly consisting of a backlight, a reflecting plate, a light guide plate, and optical sheets coupled to the inside of the mold frame on which the liquid crystal panel is seated on the upper side, And the optical sheet is coupled to a shaft formed on the mold frame while having two support protrusions vertically in the horizontal direction and support protrusions on the left and right sides in the vertical direction. The method of claim 6, The number of the support protrusions formed on the left and right sides in the longitudinal direction of the optical sheet, the backlight assembly, characterized in that one or more. The method of claim 6, The support protrusions formed on the optical sheet are coupled while having a coupling margin up, down, left and right. The method of claim 6, The optical sheet is fixed to the mold frame is a backlight assembly, characterized in that coupled to distribute the force parallel to the upper and lower sides, the left and right sides in the vertical direction.