KR102237160B1 - Backlight unit and display apparatus having the same - Google Patents

Abstract

The backlight unit according to the embodiment includes a liquid crystal panel; At least one or more light sources; A bottom cover for accommodating the one or more light sources inside; A support disposed on the top of the bottom cover; And an optical unit disposed on the light source unit, wherein the optical unit includes a diffusion plate; And an optical sheet disposed on the diffusion plate, wherein the support and the diffusion plate are bonded to each other.
In the embodiment, by bonding the support and the diffusion plate, there is an effect of preventing the occurrence of a circle or oval-shaped mura by preventing the bending of the diffusion plate and sagging the liquid crystal panel. In addition, the embodiment enables a structure in which the panel is in full contact with the optical sheet, so that there is no need to form a gap for preventing mura, which enables slimming of the display device.

Description

Backlight unit and display device including the same {BACKLIGHT UNIT AND DISPLAY APPARATUS HAVING THE SAME}

The embodiment relates to a thin display device with improved display quality.

With the recent development of the information society, the demand for the display field is also increasing in various forms, and in response to this, various flat panel display devices with features such as thinner, lighter, and low power consumption, such as liquid crystals. Research is being conducted on a liquid crystal display device, a plasma display panel device, and an organic light emitting diode display device.

A liquid crystal display device includes a panel and a backlight unit that provides light to the panel. The backlight unit mainly uses an LED element as a light source, and the backlight unit includes a diffusion plate and a prism sheet in order to generate a light diffusion effect and uniform luminance.

In recent years, research has been conducted to increase the size of a backlight unit that provides light to the panel as the size of the panel is required to be increased, and a direct-type structure is mainly used in an extra-large backlight unit.

In the case of the direct type type, as part of implementing a high-brightness backlight, a light source is selectively disposed under the liquid crystal panel.

In the direct type method, a diffuser plate is formed to diffuse light generated from a light source such as an LED device and improve visibility, and an optical sheet is laminated on the diffuser plate. A support stand is formed to support the diffusion plate and the optical sheet, which separates the light source and the diffusion plate by a certain distance to fully utilize the viewing angle of the light source to diffuse light.

However, in the direct-type method, when the diffusion plate and the optical sheet partially contact the liquid crystal panel, a circular or elliptical mura is generated. In particular, in a very large structure, luminance unevenness is caused by the mura. To improve the Mura, a gap is formed between the panel and the diffusion plate in consideration of the amount of deflection of the panel and the amount of warpage of the diffusion plate. Due to this gap design, the thickness of the direct type backlight unit There is a drawback of getting thicker.

In order to solve the above problems, an object of the embodiment is to provide a backlight unit for preventing luminance unevenness and a display device including the same.

In order to achieve the above object, the backlight unit according to the embodiment includes a liquid crystal panel; At least one or more light sources; A bottom cover for accommodating the one or more light sources inside; A support disposed on the top of the bottom cover; And an optical unit disposed on the light source unit, wherein the optical unit includes a diffusion plate; And an optical sheet disposed on the diffusion plate, wherein the support and the diffusion plate are bonded to each other.

The embodiment has an effect of preventing the diffusion plate from bending by using the bonding structure of the diffusion plate and the support.

In addition, the embodiment has an effect of preventing the panel from sagging downward by using the bonding structure of the diffusion plate and the support.

In addition, the embodiment has an effect of preventing the diffusion plate and the optical sheet from partially contacting the liquid crystal panel, thereby preventing the occurrence of a circular or elliptical luminance Mura.

In addition, the embodiment enables a structure in which the panel is in full contact with the optical sheet, so that there is no need to form a gap for preventing mura, which enables slimming of the display device.

In addition, since the embodiment can prevent the bending of optical components by using the bonding structure of the diffusion plate and the support, it is possible to increase the size.

1 is a cross-sectional view showing a conventional direct-type display device.
2 is a top view illustrating a light source and a support arranged on a reflector in a conventional direct display device.
3 is a diagram illustrating a cause of occurrence of Mura in a conventional direct-type display device.
4 is a diagram illustrating a Mura occurrence in a conventional direct-type display device.
5 is a cross-sectional view illustrating a direct display device according to an exemplary embodiment.
6 is a cross-sectional view showing an integrated structure of a diffusion plate and a support according to an embodiment.
7A to 7D are cross-sectional views showing various modified examples of a diffusion plate and a support.

Hereinafter, embodiments will be described in detail with reference to the drawings.

1 is a cross-sectional view showing a conventional direct-type display device, and FIG. 2 is a top view illustrating a light source and a support arranged on a reflector in a conventional direct-type display device.

1 and 2, a conventional display device includes a liquid crystal panel 110, a backlight unit disposed under the panel 110, and a guide panel 127 accommodating the panel 110 and the backlight unit. ), a top case 128 and a bottom cover 112.

The liquid crystal panel 110 serves to display a screen. The liquid crystal panel 110 includes a thin film transistor (TFT) substrate (not shown) and a color filter (CF) substrate (not shown) provided on the TFT substrate.

In the TFT substrate, a matrix-type TFT is formed, and the source and gate terminals of the TFTs are connected to a data line and a gate line, respectively, and a pixel electrode is connected to a drain terminal. The CF substrate has a color filter on one surface and a common electrode made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the color filter.

On one side of the TFT substrate, a driving IC such as a data driving IC and a gate driving IC are disposed, and the data driving IC and the gate driving IC are formed by a tape carrier package (TCP), such as a data TCP and a gate TCP, on one side of the TFT substrate. Is connected with. The driving IC generates a data signal, a gate driving signal, which is a signal for driving the liquid crystal panel, and a plurality of timing signals for applying these signals at an appropriate time, and transmits the gate driving signal and the data driving signal to the gate line of the liquid crystal panel. And each of the data lines.

The backlight unit may be disposed under the liquid crystal panel 110. The backlight unit serves to provide light to the liquid crystal panel 110. The backlight unit may include a light source unit, a reflective plate 116 disposed under the light source unit 120, and an optical unit disposed on the light source unit 120.

The light source unit may include a light source 120 and a printed circuit board 114 on which the light source 120 is mounted.

In this case, the light source 120 may be an LED device.

The light source 120 may be an R, G, B light-emitting diode that emits monochromatic light of R (Red), G (Green), and B (Blue) or a light-emitting diode that emits white light. When a light source emitting monochromatic light is used, monochromatic light sources 120 of R, G, B are alternately arranged at regular intervals, and monochromatic light emitted therefrom may be mixed into white light and then supplied to the liquid crystal panel 110. In contrast, when the light source 120 emitting white light is used, white light may be supplied to the liquid crystal panel 110 by disposing a plurality of light sources 120 at predetermined intervals.

When the white light source 120 is an LED element, it is composed of a blue LED element that emits blue light and a phosphor that absorbs blue monochromatic light to emit yellow light, and blue monochromatic light output from the blue LED element and yellow monochromatic light emitted from the phosphor. The mixture may be mixed and supplied to the liquid crystal panel 110 as white light.

The printed circuit board 114 may be formed of a metal material or may be a flexible printed circuit board having excellent bending. In the case of a printed circuit board formed of a metal material, there is an effect of increasing the heat dissipation effect, and in the case of a flexible printed circuit board, it is possible to reduce the thickness by reducing the thickness. A circuit (not shown) may be formed inside the printed circuit board 114. Accordingly, external power may be supplied to the light source 120 through the circuit.

The reflector 116 may be disposed under the light source 120. A printed circuit board 114 may be disposed under the reflective plate 116. The reflector 116 may be made of an ESR (Enhanced Specular Reflector, ESR) material having a very high reflectivity. The reflector made of ESR is silver or white with 98% reflectance and 2% transmittance, and most of the light incident on the reflector is reflected toward the liquid crystal panel.

The optical unit may be disposed above the light source 120. The optical unit may diffuse and condensate light generated by the light source unit 120. Such an optical unit may include a diffusion plate 124 and a plurality of optical sheets 126 disposed on the diffusion plate 124.

The liquid crystal panel 110 may be disposed on the optical sheet 126. The liquid crystal panel 110 is fixed by the guide panel 127 and is disposed to be spaced apart from the optical sheet 126 at a certain distance.

The diffusion plate 124 may be formed of a transparent material having diffusion beads formed therein. The diffusion plate 124 may be disposed to be spaced apart from the light source 120 by a predetermined distance. The diffusion plate 124 may be disposed to have a predetermined thickness so that it can be applied to an extra-large model.

A plurality of optical sheets 126 may be disposed on the diffusion plate 124. The optical sheet 126 may refract light to improve linearity of light. The optical sheet 126 may be composed of a plurality of prism sheets. The prism sheet may be arranged in two so that the prism intersects in a direction perpendicular to the x, y axis directions or three so that the prism intersects in the x, y, z axis directions. The thickness of the optical sheet 126 may be smaller than the thickness of the first diffusion plate 124.

As shown in FIG. 2, the support 122 may be disposed on the reflector 116. The support 122 is disposed to be alternately with the light source 120.

As shown in FIG. 3, in the conventional direct display device, when the backlight unit is driven, the diffusion plate 124 is bent due to heat and the liquid crystal panel 110 is sagged. In addition, as the product became larger, warpage of the diffusion plate 124 and sagging of the liquid crystal panel 110 occurred. For this reason, the diffusion plate 124 and the liquid crystal panel 110 partially contacted the central portion of the backlight.

As shown in FIG. 4, as the diffusion plate 124 and the liquid crystal panel 110 partially contact each other at the center of the backlight, a circle or elliptical luminance Mura was generated on the display screen. In the conventional direct-type display device, in order to prevent the occurrence of such luminance Mura, the panel 110 and the optical sheet 126 are designed to be spaced apart at a constant distance, but this increases the thickness of the display device. There was a downside.

5 is a cross-sectional view illustrating a direct display device according to an exemplary embodiment.

It can be seen that in the display device according to the embodiment, the support 122 and the diffusion plate 124 are joined by the bonding member 210 to prevent sagging of the liquid crystal panel 110 and bending of the diffusion plate 124. . Accordingly, it can be seen that the display device according to the exemplary embodiment prevents the diffusion plate 124 and the optical sheet 126 from partially contacting the liquid crystal panel 110, thereby improving a circle or oval shape Mura. . In addition, the display device according to the embodiment enables a structure in which the liquid crystal panel 110 is in full contact with the optical sheet 126, so that it is not necessary to form a gap for preventing Mura. It makes it possible to make the device slimmer. In addition, the display device according to the exemplary embodiment can prevent bending of the optical components by using the bonding structure of the diffusion plate 124 and the support base 122, thereby enabling a product to be enlarged.

In the display device according to the embodiment, the support 122 may be formed as one in the center of the display device. This is because the support 122 and the diffusion plate 124 are in contact with each other, resulting in a more robust structure. In addition, a plurality of conventional supports that are not bonded to the diffusion plate 124 may be disposed, including a support structure 122 formed as one in the center and bonded to the diffusion plate 124. In addition, the support 122 may be formed at each corner of the display device, and at this time, the support 122 has a structure that is bonded to the diffusion plate 124. In addition, a plurality of the supports 122 may be regularly arranged, and when they are arranged regularly, a pitch between the supports 122 is arranged at intervals of 60 cm. Therefore, in the case of a small product, the price can be reduced by minimizing the number of supports 122, and in the case of a large product, a display device with more robust and improved display quality by variously modifying the number and arrangement method of the supports 122 Makes it possible.

6 is a cross-sectional view showing the integrated structure of the diffusion plate 124 and the support 122 according to the embodiment. The adhesive member 210 may be formed between the diffusion plate 124 and the support base 122. By the adhesive member 210, the diffusion plate 124 and the support 122 may be integrally formed. At this time, the adhesive member can use any material that can be bonded, and UV resin can be used.

The long rod-shaped body of the support 122 may have various modifications such as a columnar shape, a cone shape, a pyramidal shape, a cone shape, and a pyramidal shape. Accordingly, the body of the support 122 may have various shapes such as a circle, a triangle, a square, and a polygon in a horizontal cross section. In addition, the support 122 may be transparent or translucent, and may be formed by combining the two. This has an effect of improving display quality without visual recognition of the supporter 122 when viewed from the top of the display device.

As shown in FIG. 7, the bonding structure of the diffusion plate 124 and the support 122 may have various modifications.

As shown in [a] of FIG. 7, an adhesive member 210 is formed on the upper portion of the long rod-shaped body of the support member 122, and a diffusion plate 124 is disposed on the upper portion of the adhesive member 210. I can. At this time, since there is no deformation of the shape of the support base 122 and the diffusion plate 124, the process is simple and the structure is easily bonded without increasing the cost.

As shown in FIG. 7B, a concave portion 224 is formed in the lower portion of the diffusion plate 124, and a protruding portion 226 is formed on the upper portion of the body of the support base 122 to be bonded. In this case, the adhesive member 210 may be disposed between the concave portion 224 of the diffusion plate 124 and the protruding portion 226 of the support 112. Accordingly, the area in which the adhesive member 210 is disposed can be minimized, and a more robust bonding structure is possible. The protrusion 226 of the support 122 may have the same color as the body, and may be formed in two different colors. When two different colors are used, the protrusion 226 of the support base 122 is darkened so that the bonded part is not visible when driving the backlight using the bonding structure. By using color, there is an effect of improving luminance by reflecting light generated from the light source 120.

As shown in [d] of FIG. 7, the concave portion 224 formed in the diffusion plate 124 and the protrusion portion 226 formed in the support 122 may be formed as one or two, which is more rigidly bonded. Makes the rescue possible.

As shown in [c] of FIG. 7, the concave portion 224 of the diffusion plate 124 is formed with a female threaded portion 220, and the protrusion 226 of the support base 122 is formed with the diffusion plate 124. The male screw portion 222 for screwing may be integrally formed. Through this, it enables a more robust bonding structure without any other adhesive member 210.

In the center of the conventional direct type backlight, the diffusion plate 124 and the liquid crystal panel 110 partially contact each other, and it can be visually confirmed that a luminance Mura of a circle or an ellipse is generated on the display screen. The backlight according to an embodiment of the present invention may more effectively prevent luminance Mura that may occur in a product by forming a bonding structure between the support 122 and the diffusion plate 124.

Although described above with reference to the drawings and embodiments, those skilled in the art will understand that the embodiments can be variously modified and changed without departing from the technical spirit of the embodiments described in the following claims. I will be able to.

100: direct type liquid crystal display 110: panel
112: bottom cover 114: printed circuit board
116: reflector 120: light source
122: support 124: diffusion plate
126: optical sheet 127: guide panel
128: top case 210: adhesive member
220: female thread 222: male thread
224: recess 226: protrusion

Claims (17)

Liquid crystal panel;
At least one light source;
A bottom cover for accommodating the at least one light source therein;
A plurality of first supports and a plurality of second supports disposed on the top of the bottom cover; And
An optical unit disposed on the at least one light source;
The optical unit includes a diffusion plate and an optical sheet disposed on the diffusion plate;
The plurality of first supports and the diffusion plate are joined, and the plurality of second supports and the diffusion plate are not joined,
The liquid crystal panel and the optical sheet are in front contact,
The diffusion plate has a flat back,
An adhesive member is disposed between the plurality of first supports and the flat rear surface of the diffusion plate.
delete The method of claim 1,
The adhesive member is a backlight unit, characterized in that the UV resin.
Liquid crystal panel;
At least one light source;
A bottom cover for accommodating the at least one light source therein;
A first support and a plurality of second supports disposed on the top of the bottom cover; And
An optical unit disposed on the at least one light source;
The optical unit includes a diffusion plate and an optical sheet disposed on the diffusion plate;
The first support and the diffusion plate are joined, and the plurality of second support and the diffusion plate are not joined,
The liquid crystal panel and the optical sheet are in front contact,
The diffusion plate has two concave portions and the first support has two protrusions,
The backlight unit, characterized in that the two concave portions of the diffusion plate and the two protrusions of the first support are bonded to each other.
delete delete delete delete The method of claim 1,
Each of the plurality of first supports has a long rod-shaped body,
The body is a backlight unit, characterized in that any one of a columnar shape, a cone shape, a pyramidal shape, a cone shape, and a pyramidal shape.
The method of claim 9,
The body is a backlight unit, characterized in that the horizontal cross section is any one of a circle, a triangle, a square, and a polygon.
The method of claim 1,
The plurality of first support is a backlight unit, characterized in that any one of a transparent or translucent shape, respectively.
The method of claim 4,
The body of the first support has a white color so as to reflect light of the at least one light source, and the two protrusions of the first support are provided with the first support so that the junction with the two recesses of the diffusion plate is not visually recognized. 1 Backlight unit, characterized in that it has a darker color than the body of the support.
delete The method of claim 1,
The plurality of first supports are formed at each corner of the display device.
The method of claim 1,
The plurality of first supports are regularly arranged,
Backlight unit, characterized in that the pitch (Pitch) between the supports are arranged at intervals of 60cm.
delete delete

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