KR20080002157A - Back light assembly and liquid crystal display device having the same - Google Patents

Abstract

A back light assembly and an LCD(Liquid Crystal Display) having the same are provided to homogenizing color and brightness of light by perfectly mixing RGB(Red, Green and Blue) light of the back light assembly. A back light assembly(100) comprises a receiving vessel(200), a light generating unit(300) and a diffuser plate(400). The light generating unit generates light by being received in the receiving vessel, and has plural point light source groups(310) where first to third LEDs(Light Emitting Diodes) for emitting RGB(Red, Green and Blue) light are collected one by one. The diffuser plate is disposed in an upper part of the light generating unit. In the diffuser plate, protrusion units(410) are formed between the point light source groups in correspondence to plural color-mixed areas where the RGB light are emitted at the same ratio.

Description

BACK LIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

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

FIG. 2 is a perspective view illustrating the point light source group shown in FIG. 1 in detail.

3 is a perspective view illustrating protrusions according to an exemplary embodiment of the diffusion plate illustrated in FIG. 1.

4 is a plan view illustrating a mixed color region formed by the point light source groups illustrated in FIG. 1.

5 is a perspective view illustrating a relationship between the protrusion of FIG. 3 and the mixed region.

6 is a perspective view illustrating protrusions according to another exemplary embodiment of the diffusion plate illustrated in FIG. 1.

7 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: backlight assembly 200: storage container

300: light generating unit 310: point light source group

320: first light emitting diode 330: second light emitting diode

340: third light emitting diode 360: mixed color region

362: first virtual line 364: second virtual line

400, 450: diffuser plate 410, 460: protrusion

500 optical sheet 600 liquid crystal display panel

700 driving circuit portion 800 liquid crystal display device

The present invention relates to a backlight assembly and a liquid crystal display device having the same, and more particularly, to a backlight assembly and a liquid crystal display device having the same that can uniform the color and brightness of light.

A liquid crystal display generally includes a backlight assembly for supplying light and a liquid crystal display panel for displaying an image using the light.

The backlight assembly generates light using various kinds of light sources. For example, the backlight assembly may include a light emitting diode that generates light using semiconductor characteristics.

The light emitting diode is divided into a white light emitting diode which generates white light alone, and a red, green and blue light emitting diode which emits white light by mixing red light, green light, and blue light. Here, the white light emitting diode is a small liquid crystal display such as a portable electronic device. In addition, red, green, and blue light emitting diodes have excellent color reproducibility and are used in large liquid crystal displays such as TVs.

However, as the size of a large liquid crystal display device becomes thinner recently, the backlight assembly becomes thinner, and thus there is a problem in that some colors are excessively recognized on the screen due to a lack of a space where red light, green light and blue light are mixed with each other.

Accordingly, the present invention has been made in view of the above problems, and the present invention provides a backlight assembly and a liquid crystal display device having the same, which uniformly mixes the red, green, and blue light of the backlight assembly to uniform the color and brightness of the light. .

The backlight assembly according to an aspect of the present invention includes a storage container, a light generating unit, and a diffusion plate. The light generating unit has a plurality of point light source groups in which the first, second, and third light emitting diodes, which are stored in the storage container and generate light, emit one red light, one green light, and one blue light. The diffusion plate is disposed above the light generating unit, and protrusions are formed to correspond to a plurality of mixed regions in which the blue light, the green light, and the blue light are emitted at the same ratio between each of the point light source groups.

The point light source groups may be arranged in a lattice shape along the first axis and a second axis perpendicular to the first axis in the storage container. The point light source group has a triangular shape in which the first and third light emitting diodes are disposed at both ends of the bottom side with the second light emitting diode as a vertex.

Here, the second light emitting diodes are alternately disposed above and below the bottom side along the first axis. In addition, the second light emitting diode is disposed alternately between the first and the third light emitting diode along the second axis.

The mixed regions may include first virtual lines connecting a center of the point light source groups in which the second light emitting diode is disposed above the bottom side, and a second light emitting diode disposed below the bottom side. Second virtual lines connecting centers of the point light source groups in the first direction and in a second direction symmetrically along the first axis have a rhombus shape formed while meeting each other.

Accordingly, the protruding portion has a pyramid shape having the mixed area as a bottom surface. Here, the upper end of the protrusions may have a rounded shape.

According to an aspect of the present invention, a liquid crystal display device includes a storage container, a plurality of first, second, and third light emitting diodes, each of which is stored in the storage container and generates light, and emits red, green, and blue light, respectively. A light generating unit having point light source groups of and a plurality of mixed color regions disposed above the light generating unit, wherein the blue light, green light, and blue light are emitted at the same ratio between each of the point light source groups; A backlight assembly including a diffuser plate having protrusions formed thereon, and a liquid crystal display panel disposed on the diffuser plate to display an image through light generated from the point light source groups.

According to such a backlight assembly and a liquid crystal display device having the same, a color and brightness of light are arranged by disposing a diffusion plate having a protrusion formed on the point light source groups corresponding to a mixed color region in which red light, green light and blue light are emitted at the same ratio. It can be made uniform.

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

1 is an exploded perspective view showing a backlight assembly according to an embodiment of the present invention, FIG. 2 is a perspective view showing the point light source group shown in FIG. 1 in detail, and FIG. 3 is one embodiment of the diffuser plate shown in FIG. 1. A perspective view showing protrusions according to an example.

1 to 3, a backlight assembly 100 according to an embodiment of the present invention includes a storage container 200, a light generating unit 300, a diffusion plate 400, and an optical sheet 500. .

The storage container 200 is formed of a bottom portion 210 and four side portions 220 extending vertically from the bottom portion 210, whereby a storage space is formed to accommodate the light generating unit 300. Since the storage container 200 determines the appearance of the backlight assembly 100, the storage container 200 is made of a metal material having low deformation and excellent strength.

The light generating unit 300 is accommodated in the storage container 200 to generate light. The light generating unit 300 includes point light source groups 310 in which the first, second, and third light emitting diodes 320, 330, and 340 that emit red light, green light, and blue light are collected.

The point light source groups 310 are arranged in a lattice form along a first axis x and a second axis y perpendicular to the first axis x. In addition, the point light source group 310 has a triangular shape in which the first and third light emitting diodes 320 and 340 are disposed at both ends of the bottom side with the second light emitting diode 330 as a vertex.

The first light emitting diode 320 includes a body 322 and a light emitting part 324 inserted into and fixed in the body 322 to substantially generate light. The light emitter 324 may generally have a convex lens shape.

Meanwhile, the light generating unit 300 further includes a power applying plate 350 coupled to the lower portion of the body 322 to apply driving power to the light emitting unit 324. The power applying plate 350 is electrically connected to an external power supply device (not shown).

Accordingly, the body 322 has a flat bottom portion in order to facilitate coupling with the power applying plate 350. For example, the body 322 may have a cuboid shape.

Since the second and third light emitting diodes 330 and 340 have the same structure as the first light emitting diode 320 except for the light emitting color, a detailed description thereof will be omitted.

The first, second, and third light emitting diodes 320, 330, and 340 are respectively spaced apart by a predetermined distance. This is to prevent electrical interference generated when the first, second, and third light emitting diodes 320, 330, and 340 contact each other.

In addition, in the present embodiment, the first, second, and third light emitting diodes 320, 330, and 340 are not defined to emit light of a specific color, respectively, but only to emit one of red light, green light, and blue light. . However, for convenience of description, it is assumed that the first light emitting diode 320 emits red light, the second light emitting diode 330 emits green light, and the third light emitting diode 340 emits blue light.

The light generating unit 300 has excellent color reproducibility than a Cold Cathode Fluorescent Light (CCFL) that emits white light including all wavelength bands of red light, green light, and blue light. This is because the first, second, and third light emitting diodes 320, 330, and 340 of the light generating unit 300 emit red light, green light, and blue light clearly, unlike cold cathode fluorescent lamps.

The diffusion plate 400 is disposed above the light generating unit 300. Protrusions 410 are formed on the diffusion plate 400. The protrusions 410 are disposed correspondingly between the point light source groups 310. The protrusions 410 have a pyramid structure in which the base has a square shape. For example, the bottom surface of the protrusion 410 is formed in a parallelogram.

Accordingly, the diffusion plate 400 serves to mix and collect light incident on the bottom surfaces of the protrusions 410. For example, the diffusion plate 400 is made of a poly methyl methacrylate (PMMA) material.

The protrusions 410 are in contact with each other and have a constant pattern. Specifically, the protrusions 410 have a pattern formed by being connected in a diagonal direction because the bottom surface is formed in a parallelogram. This pattern is formed because the point light source groups 310 are arranged in a lattice form along the first and second axes (x, y). In addition, the protrusion 410 may be formed by changing a mold for manufacturing the diffusion plate 400.

The optical sheet 500 is disposed above the diffuser plate 400. The optical sheet 500 improves the characteristics of the light incident from the diffusion plate 400. For example, the optical sheet 500 may include a diffusion sheet for diffusing the light emitted from the diffusion plate 400 and a light collecting sheet for condensing.

As such, the backlight assembly 100 is disposed above the backlight assembly 100 by mixing and condensing red light, green light, and blue light through the protrusion 410 of the diffusion plate 400 between the point light source groups 310. It is possible to supply light of uniform color and brightness to the liquid crystal display panel.

4 is a plan view illustrating a mixed color region formed by the point light source groups illustrated in FIG. 1, and FIG. 5 is a perspective view illustrating a relationship between the protrusion of FIG. 3 and the mixed color region.

1, 4, and 5, the point light source groups 310 are disposed to have a predetermined pattern along the first and second axes x and y.

In detail, the point light source groups 310 alternate with the upper and lower sides of the point light source groups 310 based on the first and third light emitting diodes 320 and 340 of which the second light emitting diode 330 corresponds to the lower side along the first axis x. Is placed. That is, as the point light source groups 310 move along the first axis x, only the position of the second light emitting diode 330 is changed.

In addition, the point light source groups 310 are disposed alternately with the first and third light emitting diodes 320 and 340 with the second light emitting diode 330 as the center along the second axis y. That is, as the point light source groups 310 move along the second axis y, only the positions of the first and third light emitting diodes 320 and 340 are changed.

This is because the first, second, and third light emitting diodes 320, 330, and 340, which emit light of different colors in the point light source groups 310, are appropriately mixed with each other so that the optimal white light is emitted. .

Accordingly, the mixed region 360 corresponding to the bottom surface of the protrusion 410 is defined. Here, the mixed color region 360 refers to a region in which red light, green light, and blue light are emitted at the same ratio to uniformly color light among the point light source groups 310.

In detail, the mixed region 360 is defined by two first and second virtual lines 364 formed according to a pattern of the point light source groups 310. The first virtual lines 362 have a point where a second light emitting diode 330 corresponding to a vertex of the point light source groups 310 is disposed above the first and third light emitting diodes 320 and 340 corresponding to the bottom. The centers of the light source groups 310 are formed by connecting in a first direction a.

That is, each time the first virtual line 362 is moved one row along the second axis y, the first virtual lines 362 are connected while moving two columns along the first axis x. Here, the first direction a is a direction that proceeds while forming an acute angle with the first axis x.

The second virtual lines 364 are formed of the point light source groups 310 of which the second light emitting diode 330 is disposed below the first and third light emitting diodes 320 and 340. It is formed by connecting along the second direction (b). The second direction a progresses while forming an obtuse angle with the first axis x, and is a direction substantially symmetrical along the first direction a and the first axis x. That is, like the first virtual lines 362, the second virtual lines 364 are connected by moving two columns along the first axis x every time one row is moved along the second axis y. do.

The first and second virtual lines 364 meet each other, and a plurality of mixed regions 360 having parallelograms are formed therein. When only one of the mixed regions 360 is selected and described, any two of the first, second, and third light emitting diodes 320, 330, and 340 may be included, and the other may be partially cut. The state eventually includes one.

That is, one mixed area 360 includes all of the first, second, and third light emitting diodes 340. This means that the red light, the green light, and the blue light are emitted at the same ratio in the mixed region 360.

Accordingly, the protrusion 410 of the diffusion plate 400 has a bottom surface of a parallelogram in correspondence with the mixed region 360. Meanwhile, first distances of the point light source groups 310 adjacent to the first side L1 and the second side L2 connected to both ends of the first side L1 along the first axis x are arranged along the first axis x. Comparing and formulated through the second distance (d2) of the adjacent point light source group 310 along the second axis (d1) and the first side (L1) and the second side (L2) as shown below Is calculated to be the same value.

Accordingly, it can be seen that the mixed region 360, that is, the bottom surface of the protrusion 410 has a rhombus shape that is more detailed than a parallelogram.

In addition, the protrusion 410 may change the height (h) to change the mixing and concentration of the point light source group 310. At this time, the height (h) may have a variety of values because the mixing and condensing rate is different depending on the characteristics of the point light source group (310). However, the height h, after all, affects the thickness of the backlight assembly 100, so it is desirable to make it at least small.

Therefore, the diffusion plate 400 mixes and condenses the light emitted from the mixed color region 360 through the protrusion 410 having a bottom surface corresponding to the mixed color region 360 in which the red light, the green light, and the blue light are emitted at the same ratio. The color and brightness of light can be made uniform.

6 is a perspective view illustrating protrusions according to another exemplary embodiment of the diffusion plate illustrated in FIG. 1.

1, 4 and 6, the upper end of the protrusion 460 of the diffusion plate 450 has a rounded shape.

That is, the height h2 of the protrusion 460 is lowered. In this case, a problem may occur in the mixing and condensing functions by the protrusion 460, but as shown in FIG. 4, the point light source groups 310 are not disposed in the central portion of the mixed region 360, and thus the mixing and condensing functions are performed. You can ignore the function.

Accordingly, the diffusion plate 450 may round the top of the protrusion 460 to minimize the height h2, thereby preventing the entire thickness of the backlight assembly 100 from increasing.

7 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

In the present embodiment, since the backlight assembly is the same as the structure shown in FIGS. 1 to 6, the same reference numerals are used, and detailed description thereof will be omitted.

Referring to FIG. 6, the liquid crystal display 800 according to the exemplary embodiment of the present invention is disposed on the backlight assembly 100 and the optical sheet 500 to supply light, and is generated from the point light source groups 310. It includes a liquid crystal display panel 600 for displaying an image through the light.

The liquid crystal display panel 600 includes a first substrate 610, a second substrate 620 coupled to face the first substrate 610, and a liquid crystal interposed between the first substrate 610 and the second substrate 620. Layer (not shown).

The first substrate 610 is a TFT substrate in which a thin film transistor (hereinafter, referred to as TFT), which is a switching element, is formed in a matrix form. The second substrate 620 is a color filter substrate in which RGB pixels for implementing colors are formed in a thin film form.

In addition, the liquid crystal display device 800 further includes a driving circuit unit 700 for driving the liquid crystal display panel 600.

The driving circuit 700 includes a data printed circuit board 710 for supplying a data driving signal to the liquid crystal display panel 600, a gate printed circuit board 720 for supplying a gate driving signal to the liquid crystal display panel 600, and data printing. The data driving circuit film 730 connects the circuit board 710 to the liquid crystal display panel 600, and the gate drive circuit film 740 connects the gate printed circuit board 720 to the liquid crystal display panel 600. .

Meanwhile, the liquid crystal display device 800 may further include a top chassis coupled to the storage container 200 while fixing the edge of the liquid crystal display panel 600.

According to such a backlight assembly and a liquid crystal display having the same, by disposing a diffuser plate on top of the point light source groups, a diffuser plate for mixing and condensing light for a mixed color region in which red light, green light and blue light are emitted at the same ratio. The color and luminance of the light supplied to the liquid crystal display panel can be made uniform.

Although the detailed description of the present invention described above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art will have the idea of the present invention described in the claims to be described later. And it will be understood that the present invention can be modified and changed in various ways without departing from the technical scope.

Claims (9)

A storage container; A light generating unit having a plurality of point light source groups, the first, second and third light emitting diodes, each of which is stored in the storage container and generates light and which emits red, green and blue light, respectively; And And a diffuser plate disposed above the light generating unit and having protrusions formed to correspond to a plurality of mixed regions in which the blue light, the green light, and the blue light are emitted at the same ratio between each of the point light source groups. The backlight assembly of claim 1, wherein the point light source groups are arranged in a lattice form in the storage container along a first axis and a second axis perpendicular to the first axis. 3. The backlight assembly of claim 2, wherein the point light source group has a triangular shape in which the first and third light emitting diodes are disposed at both ends of a bottom side of the second light emitting diode. The backlight assembly of claim 3, wherein the second light emitting diodes are alternately disposed above and below the bottom side along the first axis. 5. The backlight assembly of claim 4, wherein the second light emitting diodes are alternately arranged with the first and third light emitting diodes along the second axis. The method of claim 5, wherein the mixed regions include first virtual lines connecting the centers of the point light source groups in which the second light emitting diode is disposed above the bottom side and along the first direction, and the second light emitting diode being the bottom side. And a second virtual line connecting centers of the point light source groups disposed below the second direction in a first direction and a second direction symmetrical along the first axis to have a rhombus shape formed to meet each other. The backlight assembly of claim 6, wherein the protrusion has a pyramid shape with the mixed area underneath. 8. The backlight assembly of claim 7, wherein the tops of the protrusions are rounded. A light generating unit having a plurality of point light source groups in which a first, second and third light emitting diodes, each of which is stored in the storage container and generates light and emits red light, green light and blue light, are gathered one by one, and the light A backlight assembly disposed above the generating unit, the backlight assembly including a diffuser plate having protrusions formed to correspond to a plurality of mixed color regions in which the blue light, the green light, and the blue light are emitted at the same ratio between each of the point light source groups; And And a liquid crystal display panel disposed on the diffusion plate to display an image through light generated from the point light source groups.

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