KR20040028112A - Back light assembly for lcd and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A back light assembly for an LCD device is provided to install many light guide plates on a rear side of an LCD panel, and to dispose illuminating units for illuminating each light guide plate, thereby implementing high brightness and reducing size. CONSTITUTION: A back light assembly(1a) includes supplementary reflecting plates(60a) interposed between a separating unit(11a) and a rear side of the first light guide plate(30), between the separating unit(11a) and a front side of the second light guide plate(40), and between a front side of the first guide plate(30) and rear surfaces of front frames(20a). Light incident at predetermined angle is reflected on each light guide plate(30,40) among light incident on the light guide plates(30,40) from each lamp(51,51a), reducing light loss. The separating unit(11a) having the supplementary reflecting plates(60a) has stop projections(13a) for preventing the supplementary reflecting plates(60a) from moving. Stop projections(23a) for preventing the supplementary reflecting plates(60a) from moving are disposed in rear side sections of the front frames(20a).

Description

BACK LIGHT ASSEMBLY FOR LCD AND MANUFACTURING METHOD THEREOF}

The present invention relates to a backlight assembly for a liquid crystal display device and a method for manufacturing the same, and more particularly, to a backlight assembly for a liquid crystal display device and a method for manufacturing the same, which realize a high brightness while reducing the thickness.

A liquid crystal display device applies a voltage to a specific molecular array of a liquid crystal to convert it into another molecular array, and visually changes the optical properties such as birefringence, photoreactivity, dichroism, and light scattering characteristics of the liquid crystal cell that emit light by the molecular array. It is a display device using the modulation of light by the liquid crystal cell by converting to.

Since the liquid crystal display is a light-receiving device that displays an image by controlling the amount of light coming from the outside, a separate light source for illuminating the liquid crystal display panel, that is, a backlight assembly, is required. It is divided into edge type and direct type according to.

The edge type is installed on the side of the light guide plate where the lamp guides the light, and the light uniformity is good, the durability is long, and the liquid crystal display is thinner, but the luminance is lowered when the liquid crystal display is enlarged. The present invention is mainly applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer.

On the other hand, the direct type backlight assembly is mainly used in a liquid crystal display device having a large screen requiring high luminance because the light utilization efficiency is higher than that of the edge method.

Unless otherwise specified below, the area in which the reflecting plate is located is referred to as the rear, and the direction in which the liquid crystal display panel is located is referred to as the front.

As shown in FIG. 1, a conventional liquid crystal display device includes a liquid crystal display panel 300 on which an image is displayed, and a backlight assembly provided behind the liquid crystal display panel 300 to supply light to the liquid crystal display panel 300. And a front cover 500 for blocking the front edge surface of the liquid crystal display panel 300.

The backlight assembly 100 is provided at a predetermined distance from the lamp 151 for generating light, the reflector 160 positioned behind the lamp 151, and the reflector 160 above the lamp 151. The optical sheet layer 180 in which the diffuser plate 181, the prism sheet 183, and the like are stacked are stacked, and the support frame 110 accommodates the reflective plate 160 and the optical sheet layer 180.

The reflecting plate 160 is disposed behind the optical sheet layer 180 at a predetermined distance from the optical sheet layer 180, and a plurality of lamps 151 are disposed at predetermined intervals on the front surface of the reflecting plate 160. . The reflecting plate 160 reduces the loss of light emitted from the lamp 151 by reflecting the light emitted backward from the light emitted from the lamp 151 toward the optical sheet layer 180.

The support frame 110 blocks the front edge surface of the optical sheet layer 180, and an accommodation space is formed therein to accommodate and support the optical sheet layer 180 and the reflector plate 160.

Meanwhile, the liquid crystal display panel 300 is disposed in front of the support frame 110 to contact and support the rear edge surface of the liquid crystal display panel 300. In addition, an inverter (not shown) is provided on the rear surface of the reflector 160 to convert a DC current supplied from the outside into an AC current and supply the lamp 151.

However, such a conventional backlight assembly 100 has a front region (“a” in FIG. 2) immediately before the lamp 151 in front of a space (“b” in FIG. 2) between the lamp 151 and the lamp 151. There is a problem that the above line is generated in the area of the liquid crystal display panel 300 that is brighter than the area “a”. In order to prevent such bright lines, the distance Q between the lamp 151 and the optical sheet layer 180 should be increased, which causes a thickening of the liquid crystal display. In addition, by reducing the interval (P) between the lamps 151, it is possible to reduce the generation of bright lines, but there is a problem that the increase in manufacturing cost and the power consumption is increased because more lamps 151 should be installed.

In addition, since the backlight assembly 100 of the direct type has a structure in which the lamp 151 directly emits light at the rear of the liquid crystal display panel 300 and the optical sheet layer 180, the heat generated from the lamp 151 may be reduced. There is a problem in that the LCD panel 300 and the circuit components are deteriorated to cause a failure.

In addition, since the inverter is located close to the rear surface of the reflector 160, that is, the rear of the lamp 51, the liquid crystal display panel 300 is formed by mutual interference in a region where the driving frequency of the lamp 151 and the driving frequency of the inverter are similar. ), There is a problem that a wave pattern occurs. In order to solve such a problem, the ITO sheet 185 is installed in front of the diffusion plate 181. The ITO sheet 185 has a low light transmittance, which is a factor that hinders the brightness of the liquid crystal display device, and the manufacture thereof. There is a problem in that the cost is high and the manufacturing cost is increased due to the increase of labor.

In the direct backlight assembly 100, when one of the lamps 151 needs to be replaced due to a failure or the like, there is a problem in that the entire chassis and the support frame 110 need to be opened.

Accordingly, an object of the present invention is to provide a backlight assembly for a liquid crystal display device and a method of manufacturing the same, in which the thickness is reduced while achieving high brightness.

1 is a schematic cross-sectional view of a conventional liquid crystal display device,

2 is a view showing the distribution of light of the conventional backlight assembly.

3 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention;

4 is a schematic cross-sectional view of a liquid crystal display according to a second embodiment of the present invention;

5 to 8 illustrate an assembly step of a backlight assembly according to a second embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1: backlight assembly 3: liquid crystal display panel

5: front panel 10: support frame

11,11a: Spaced rib 13a, 23a: Stopping protrusion

20,20a: front frame 30: first light guide plate

31,41: light scattering part 40: second light guide plate

50,50a: lighting unit 51,51a: lamp

53, 53a: lamp reflector 60: reflector

60a: secondary reflector 70: rear chassis

80: optical sheet layer 81: diffuser plate

83: Prism Sheet

According to the present invention, in the backlight assembly coupled to the rear of the liquid crystal display panel of the liquid crystal display device, a plurality of light guide plates disposed at a rearward spaced apart from the rear of the liquid crystal display panel, and the circumference of the edge of each light guide plate And an illumination unit disposed in at least one region of the panel to illuminate the respective light guide plates.

The light guide plate may further include a support frame disposed between the plurality of light guide plates such that the plurality of light guide plates are spaced apart from each other, and further include a support frame that surrounds the lighting unit outside the plate direction of the light guide plates.

The light guide plate may further include a reflection plate provided at a rear side of the light guide plate disposed rearward of the plurality of light guide plates to reflect light.

It is preferable to further include an auxiliary reflecting plate interposed between the spacer and each of the light guide plates. Here, the spacing portion is preferably provided with a stopper for preventing the auxiliary reflecting plate from moving inward in the plate surface direction.

Preferably, the light guide plate further includes light scattering parts provided on surfaces of the light guide plates facing each other. Here, each of the light scattering parts is preferably an uneven pattern formed on the plate surface of the light guide plate.

In addition, the lighting unit preferably includes at least one lamp and a lamp reflector to prevent light from the lamp from radiating outward in the plane direction of each light guide plate.

The apparatus may further include a front frame interposed between the liquid crystal display panel and the light guide plate disposed at the foremost of the plurality of light guide plates.

On the other hand, the above object can also be achieved by a liquid crystal display device comprising the backlight assembly and a liquid crystal display panel provided in front of the backlight assembly.

On the other hand, the above object, in the manufacturing method of the backlight assembly coupled to the rear of the liquid crystal display panel of the liquid crystal display device, the step of providing a support frame partitioned by a spaced portion formed in the front and rear receiving space, and the support frame Accommodating a second light guide plate in a rear accommodating space of the substrate, mounting a reflecting plate on a rear side of the second light guide plate, accommodating a first light guide plate in a front accommodating space of the support frame, the support frame and the The method may also be achieved by a method of manufacturing a backlight assembly, including inserting an illumination unit in at least one region between the first light guide plate and the circumference of the edge of the second light guide plate.

The method may further include mounting an optical sheet layer in front of the first light guide plate, and installing a front frame to be in close contact with the front edge surface of the first light guide plate and the optical sheet layer.

And, it is preferable to further include the step of shielding the rear receiving space of the support frame.

Here, the lighting unit is preferably inserted by sliding between the edge of the support frame and the first light guide plate and the second light guide plate.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail, and the same reference numerals are used for the same components even if the embodiments are different, the description thereof will be omitted.

The liquid crystal display device includes a liquid crystal display panel for forming an image, and a backlight assembly provided behind the liquid crystal display panel to supply light to the liquid crystal display panel.

The liquid crystal display panel includes a color filter substrate, a thin film transistor substrate on which a switching element, a pixel electrode, and the like are formed, and a liquid crystal (not shown) interposed between both substrates. The image signal is applied to the transistor of the thin film transistor substrate via the source portion and the gate portion of the thin film transistor substrate, whereby the liquid crystal receives an electrical signal, and adjusts the light from the backlight assembly disposed behind the liquid crystal display panel. Will be configured.

In the liquid crystal display device according to the first embodiment of the present invention, as shown in FIG. 3, the liquid crystal display panel 3 on which an image is displayed and the liquid crystal display panel 3 are provided behind the liquid crystal display panel 3. The backlight assembly 1 supplies light to the front panel, and the front cover 5 blocks the front edge of the liquid crystal display panel 3.

The backlight assembly 1 may include a first light guide plate 30 and a second light guide plate 40 disposed at a rear side of the liquid crystal display panel 3 at a distance from each other, and at least around the edges of the light guide plates 30 and 40. The first lighting unit and the second lighting unit 50 and 50a are disposed in one region and illuminate toward each of the light guide plates 30 and 40.

A spaced portion 11 is interposed between the first and second light guide plates 30 and 40 so that the first and second light guide plates 30 and 40 have a spaced interval in parallel with each other. On the other hand, each of the lighting unit (50, 50a) is enclosed and supported by the support frame 10 to the outside of the plate surface direction of each light guide plate (30, 40), the interior of the support frame 10 by the spacer 11 It is divided into front and rear receiving spaces. In the embodiment of the present invention, the spacer 11 and the support frame 10 are integrally formed.

The rear side of the first LGP 30 is contacted and supported by the spacer 11 to be accommodated in the front receiving space of the support frame 10. In addition, the front of the second light guide plate 40 is supported by the spacer 11 so as to be accommodated in the rear receiving space of the support frame 10. That is, the first light guide plate 30 and the second light guide plate 40 are disposed to have a predetermined distance from each other by the spacer 11, and are accommodated in the front and rear accommodation spaces of the support frame 10, respectively.

The light scattering portion 31 is provided on the rear side plate surface of the first light guide plate 30. The light scattering unit 31 emits the light from the lighting unit 50 through the vertical scattering of the light emitted from the lighting unit 50 to the inside of the first LGP 30. The brightness of the liquid crystal display device is improved by being distributed. Here, the light scattering unit 31 may be formed by molding the rear side plate surface of the first light guide plate 30 in a concave-convex pattern shape and screen-printing the light scattering ink on the rear side plate surface of the first light guide plate 30, or 1 may be molded to have a light output function by mixing a material capable of scattering light in the light guide plate 30.

In addition, the light scattering part 41 may be provided on the front side plate surface of the second light guide plate 40. The light scattering portion 41 on the side of the second light guide plate 40 may be provided with the same material and shape as the light scattering portion 31 on the side of the first light guide plate 30.

The first and second lighting units 50 and 50a are installed between the edges of the first and second light guide plates 30 and 40 and the inner wall surfaces of the front and rear receiving spaces of the support frame 10, respectively. Light is emitted into the second LGPs 30 and 40.

Each of the lighting units 50 and 50a includes lamps 51 and 51a which are light sources emitting light, and light emitted from each lamp toward the outside of the light guide plates 30 and 40 in the plate direction. And lamp reflecting plates 53 and 53a for reflecting therein. By the configuration of the lighting unit (50, 50a), it is possible to minimize the loss of light emitted in the opposite direction of each light guide plate (30, 40). In addition, since the lamps 51 and 51a are provided around the edges of the light guide plates 30 and 40, a distance from an inverter (not shown) installed at the rear of the backlight assembly 1 is relatively far, and thus mutual interference is caused. It can be minimized.

The reflecting plate 60 is provided behind the second light guide plate 40. As the reflecting plate 60, one having a specular reflection function such as a silver fusion film or a white film can be used. As a result, by reflecting the light transmitted through the rear side plate surface of the second light guide plate and entering it into the second light guide plate, it is possible to minimize the loss of light emitted from the lamp 51.

The rear chassis 70 is provided at the rear of the reflector 60 to shield the rear of the rear receiving space of the support frame 10 in combination with the support frame 10. Here, a screw through hole 75 is provided in the rear chassis 70, and a screw fastening hole 15 is provided in the support frame 10 at a position corresponding to the screw through hole 75. By passing the screw 90 is fastened to the screw fastening hole 15, the rear chassis 70 is coupled to the support frame 10.

In the embodiment of the present invention, the rear chassis 70 has been described as being coupled to the support frame 10 by a screw 90, but can be coupled by various coupling methods such as hook coupling or adhesive.

Meanwhile, an optical sheet layer 80 is provided on the front surface of the first light guide plate 30 to improve the front luminance of the liquid crystal display panel 3. The optical sheet layer 80 includes a diffusion plate 81 for directing light incident from the first light guide plate 30 to the front direction of the liquid crystal display panel 3 and a prism sheet 83 for improving the luminance of the liquid crystal display device. ).

Since the diffusion plate 81 has a small amount of light in the front direction and an angle with respect to the normal direction, the light incident from the first light guide plate 30 changes the light in the normal direction to the front direction by refraction, thereby causing liquid crystals. To improve the front brightness of the display device.

The prism sheet 83 is provided laminated in front of the diffusion plate 81. Since the light emitted from the diffuser plate 81 has a large viewing angle as the diffused light, the prism sheet 83 narrows the viewing angle of the light emitted from the diffuser plate 81 to improve the front luminance of the liquid crystal display and consume power. Reduce

The front edge of the first light guide plate 30 and the front edge of the optical sheet layer 80 are blocked by the front frame 20. 3 illustrates that the front frame 20 is provided to surround the outer wall forming the front receiving space of the support frame 10, but the first light guide plate 30, the optical sheet layer 80, and the support frame 10 are provided. Of course it can be provided so that only the front of the contact. Here, the front frame 20 is coupled to the support frame 10 by various types of coupling structures such as screws, hooks and adhesive members to shield the front. In addition, a support jaw 25 in which the liquid crystal display panel 3 is inserted and supported may be provided on the front surface of the front frame 20.

4 is a schematic cross-sectional view of a liquid crystal display according to a second exemplary embodiment of the present invention. As shown, the backlight assembly 1a is disposed between the spacer 11a and the rear side plate surface of the first light guide plate 30, between the spacer 11a and the front side plate surface of the second light guide plate 40 and the first surface. An auxiliary reflecting plate 60a is interposed between the front side plate surface of the light guide plate 30 and the rear surface of the front frame 20a. As a result, the light loss is reduced by reflecting the light incident from the lamps 51 and 51a into the light guide plates 30 and 40 at a predetermined angle into the light guide plates 30 and 40.

Here, it is preferable that the stopper part 13a provided with the auxiliary reflecting plate 60a is provided with a stopper 13a for preventing the inside of the auxiliary reflecting plate from moving inward along the plate surface direction. In addition, it is preferable to provide a stopper 23a for preventing the auxiliary reflecting plate 60a interposed between the first light guide plate 30 and the rear end region of the front frame 20a.

With the above configuration, the assembling process of the backlight assembly 1a according to the second embodiment of the present invention is as follows, and will be described with reference to FIGS. 4 and 5 to 8.

First, the support frame 10 is provided on a predetermined work table such that the rear receiving space of the support frame 10 provided integrally with the spacer 11a faces upward. Then, the spacer 11a and the second light guide plate 40 are brought into close contact with each other to install the second light guide plate 40 in the rear accommodating space of the support frame 10, and then the reflector 60 is disposed on the second light guide plate 40. ) To the top (see FIG. 5).

When the above operation is completed, the rear receiving space of the support frame 10 by the rear chassis 70 while the second light guide plate 40 and the reflector 60 are accommodated in the rear receiving space of the support frame 10. Shield. Here, the rear chassis 70 is coupled to the support frame 10 by screws 90 as described above (see FIG. 6).

When the fastening of the rear chassis 70 is completed, the support frame 10 is turned upside down so that the front receiving space is upward. Then, the spacer 11a of the support frame 10 and the first light guide plate 30 are brought into close contact with each other to install the first light guide plate 30 in the front receiving space of the support frame 10, and then the optical sheet layer 80. ) Is mounted on the first light guide plate 30 (see FIG. 7). Next, the front frame 20a is brought into close contact with the edges of the first light guide plate 30 and the optical sheet layer 80 to be seated on the top of the optical sheet layer 80 (see FIG. 8).

When the installation of the front frame 20a is completed, the backlight assembly 1a is inserted into the space between the support frame 10 and the edge regions of the first and second LGPs 30 and 40, respectively. ) Is completed (see FIG. 4). Here, the lighting units 50 and 50a are inserted by sliding between the support frame 20a and the first and second light guide plates 30 and 40. As such, the lamps 51 and 51a may be slidably inserted between the support frame 10 and the first and second light guide plates 30 and 40 so that the lamps 51 and 51a may be installed. 1a) It can be replaced without disassembling the whole.

Meanwhile, the auxiliary reflector 60a may be inserted and installed between the first and second light guide plates and the support frame 10 in the same manner as the insertion method of the illumination units 50 and 50a before and after the insertion step of the illumination units 50 and 50a. have. In addition, in the installation steps of the first and second light guide plates 30 and 40, it may be installed by being seated on the spaced portion 11a of the support frame 10.

After the manufacturing of the backlight assembly a1 is completed by the above process, the liquid crystal display panel 3 is inserted into the support jaw 25 of the front frame 20a and disposed in front of the backlight assembly 1a. The assembling process of the liquid crystal display device is performed by blocking the front edge surface of the liquid crystal display panel 3 by the front cover 5.

In the above-described embodiment, two light guide plates 30 and 40 are installed in the backlight assembly 1 according to the present invention, but three or more light guide plates having a predetermined distance from each other may be installed.

In addition, although the first and second lighting units 50 and 50a according to the present invention are installed in the peripheral area around both edges of the first and second light guide plates 30 and 40, respectively, they are provided only on one side and the rear side of each light guide plate. Of course, the plate surface can be provided to be inclined.

In addition, although light scattering units 31 and 41 are provided on surfaces of the light guide plates 30 and 40 that face each other, the light scattering units may be provided on the rear side plate surfaces of the light guide plates 30 and 40, respectively. Of course, it can be provided on both the rear side plate surface.

In this way, by providing a pair of light guide plates 30 and 40 spaced apart in parallel to each other, the thickness of the light guide plate 30, 40 can be reduced compared to the direct method, and the light efficiency can be improved to realize high brightness, which can be applied to a large screen liquid crystal display device. Will be.

In addition, the lamp 51 is provided in the edge region of each of the light guide plates 30 and 40, thereby minimizing interference with the inverter to separately prevent a member such as an ITO sheet (185 in FIGS. 1 and 2) to prevent interference. There is no need to install, thereby reducing the manufacturing cost. In addition, the influence of the heat generated by the lamp 51 is reduced to reduce the deterioration of the liquid crystal display panel 3 and the like.

As described above, according to the present invention, there is provided a backlight assembly for a liquid crystal display device and a method of manufacturing the same, in which the thickness is reduced while achieving high brightness.

Claims (14)

In the backlight assembly coupled to the rear of the liquid crystal display panel of the liquid crystal display device, A plurality of light guide plates disposed at a rear of the liquid crystal display panel at a distance from each other; And an illumination unit disposed in at least one area around an edge of each of the light guide plates to illuminate the light guide plates. The method of claim 1, And a support frame disposed between the plurality of light guide plates such that the plurality of light guide plates are spaced apart from each other, and further comprising a support frame surrounding the lighting unit from outside of the light guide plates in a plate direction. The method of claim 1, The backlight assembly further comprises a reflector provided on the rear of the light guide plate disposed in the rearmost of the plurality of light guide plates to reflect light. The method of claim 2, And a sub-reflective plate interposed between the spacer and each of the light guide plates. The method of claim 4, wherein The spacing portion is a backlight assembly, characterized in that the stopper is provided to prevent the auxiliary reflector from moving inward in the plate direction. The method of claim 1, The backlight assembly further comprises a light scattering portion provided on each surface of the light guide plate to face each other. The method of claim 6, Each light scattering unit is a backlight assembly, characterized in that the irregular pattern formed on the plate surface of each light guide plate. The method according to any one of claims 1 to 7, And the lighting unit includes at least one lamp and a lamp reflector to prevent light from the lamp from radiating outward in the plane direction of each light guide plate. The method of claim 8, And a front frame interposed between the liquid crystal display panel and the light guide plate disposed at the foremost of the plurality of light guide plates. A backlight assembly according to any one of claims 1 to 8; And a liquid crystal display panel provided in front of the backlight assembly. In the manufacturing method of the backlight assembly coupled to the rear of the liquid crystal display panel of the liquid crystal display device, Providing a support frame partitioned by a spacer to define front and rear receiving spaces; Accommodating a second light guide plate in a rear accommodation space of the support frame; Mounting a reflector on the rear of the second light guide plate; Accommodating a first light guide plate in a front receiving space of the support frame; And inserting an illumination unit in at least one region between the support frame and a perimeter of the edge of the first light guide plate and the second light guide plate. The method of claim 11, Mounting an optical sheet layer in front of the first light guide plate; And installing a front frame to be in close contact with the front edge of the first LGP and the optical sheet layer. The method of claim 12, And shielding the rear accommodation space of the support frame. The method according to any one of claims 11 to 13, And the lighting unit is inserted by sliding between the support frame and the edges of the first light guide plate and the second light guide plate.