KR101368154B1 - Backlight unit and liquid crystal display having the same - Google Patents

Abstract

A backlight unit and a liquid crystal display including the same are disclosed.

The backlight unit includes a light source for emitting light; A bottom cover having a bottom portion and a side portion formed to extend from the bottom portion, the bottom cover storing the light source in an accommodation space provided by the bottom portion and the side portion; An optical sheet seated on the bottom cover and configured to diffuse or focus light emitted from the light source; And a fixing member disposed on the optical sheet and fixing the central portion of the optical sheet.

Backlight unit, light source, optical sheet, liquid crystal panel, polarizer

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY HAVING THE SAME}

1 is a cross-sectional view showing a conventional backlight unit.

FIG. 2 is a cross-sectional view illustrating a state in which an optical sheet is deformed in the backlight unit illustrated in FIG. 1.

FIG. 3 is a view illustrating a liquid crystal display equipped with a backlight unit having the modified optical sheet illustrated in FIG. 2.

4 is an exploded perspective view illustrating a backlight unit according to an exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

FIG. 6 is an exploded perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 4.

FIG. 7 is a cross-sectional view taken along the line VII-VII 'of FIG. 6.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS FIG.

100: liquid crystal display 110: backlight unit

112: light source 114: bottom cover

116: bottom 118: side

120: optical sheet 122: fixing member

124: support frame 126: fixing part

128: diffuser 130: reflector

132: panel guide 140: liquid crystal panel

142: first substrate 144: second substrate

162: first polarizing plate 164: second polarizing plate

The present invention relates to a backlight unit and a liquid crystal display having the same.

In general, a liquid crystal display classified into a light receiving display device includes a backlight unit mounted under the liquid crystal panel of the liquid crystal display.

1 is a cross-sectional view showing a conventional backlight unit.

Referring to FIG. 1, the conventional backlight unit 10 may be mounted under the liquid crystal panel to provide light to the liquid crystal panel.

To this end, the conventional backlight unit 10 may include a light source 12, a bottom cover 14, and an optical sheet 20. In addition, the conventional backlight unit 10 may further include a diffuser plate 28, a reflector plate 30, and a panel guide 32.

The light source 12 may be driven by a driving voltage provided from the outside to generate light, and then emit the generated light.

The bottom cover 14 may accommodate the light source 12 and the reflector 30. In addition, the bottom cover 14 may sequentially seat the diffusion plate 28 and the optical sheet 20.

To this end, the bottom cover 14 may have a bottom portion 16 and a side portion 18 formed to extend from the bottom portion 16. In this case, an accommodation space may be provided by the bottom portion 16 and the side portion 18, and the light source 12 and the reflection plate 30 may be stored in the accommodation space. Meanwhile, the diffusion plate 28 and the optical sheet 20 may be sequentially mounted on the side portion 18. Here, the edges of each of the diffusion plate 28 and the optical sheet 20 seated on the side portion 18 are formed in a shape that borders the optical sheet 20 to be fastened to the bottom cover 14. It can be fixed by).

The optical sheet 20 may diffuse or condense the light emitted from the light source 12, specifically, the light provided to the optical sheet 20 through the diffuser plate 28 after being emitted from the light source 12. . Here, at least one optical sheet 20 may be provided, and the number of specific optical sheets 20 may vary depending on the specification of the backlight unit 10.

On the other hand, in the conventional backlight unit 10 having the above configuration, the light source 12 may incidentally emit heat. However, heat emitted from the light source 12 is not easily released to the outside due to the structure of the bottom cover 14 formed to receive the light source 12. Accordingly, heat emitted from the light source 12 may be transferred to the optical sheet 20 via the diffuser plate 28.

FIG. 2 is a cross-sectional view illustrating a state in which an optical sheet is deformed in the backlight unit illustrated in FIG. 1.

As described above, when the heat emitted from the light source 12 is transferred to the optical sheet 20 via the diffuser plate 28, the optical sheet 20 may be deformed. For example, as shown in FIG. 2, the optical sheet 20 may be bent upwards. The reason why the optical sheet 20 is bent upward is that the diffusion plate 28 supports the lower front surface of the optical sheet 20 and the panel guide 32 fixes the edge of the optical sheet 20. to be.

When the optical sheet 20 is deformed, the characteristics of the optical sheet 20 may be degraded. For this reason, the brightness | luminance characteristic of the light radiate | emitted from the light source 12 and radiate | emitted via the diffuser plate 28 and the optical sheet 20 may fall.

The deformation of the optical sheet 20 is not caused only by non-insulation, but may occur as the backlight unit 10 becomes larger and thinner according to the size and thickness of the liquid crystal display device. For example, as the backlight unit 10 increases in size, the optical sheet 20 having a larger size may be bent due to its own weight.

As described above, even after the deformation of the optical sheet 20 due to heat or self weight, the optical sheet 20 may be wrinkled even if the optical sheet 20 returns to its original state. This may cause display quality degradation of the backlight unit 10 and the liquid crystal display including the same.

FIG. 3 is a view illustrating a liquid crystal display equipped with a backlight unit having the modified optical sheet illustrated in FIG. 2.

Referring to FIG. 3, when the backlight unit 10 having the modified optical sheet 20 is mounted on the liquid crystal display 1, the optical sheet 20 may be a liquid crystal panel 40 of the liquid crystal display 1. ) May be in physical contact with the polarizer 64 mounted on the lower front surface.

When physical contact between the optical sheet 20 and the polarizing plate 64 occurs, at least one of the optical sheet 20 and the polarizing plate 64 is divided by external forces such as vibration and shock, and thus, the foreign matter is separated. May occur. In this case, the cleavable foreign material may appear in the image displayed through the liquid crystal panel 40 as it is.

In addition, when physical contact between the optical sheet 20 and the polarizing plate 64 occurs, heat transmitted to the optical sheet 20 via the diffusion plate 28 is transferred to the polarizing plate 64 and / or the liquid crystal panel 40. Can be delivered.

For this reason, various defects, such as a characteristic fall of the polarizing plate 64 and / or deterioration of the liquid crystal layer of the liquid crystal panel 40, may occur. This may be recognized in the form of various spots in the image displayed through the liquid crystal panel 40.

Accordingly, an aspect of the present invention is to provide a backlight unit capable of preventing deformation of an optical sheet and a liquid crystal display having the same.

In addition, another technical problem to be achieved by the present invention is to provide a backlight unit and a liquid crystal display having the same that can prevent the display quality degradation by preventing the deformation of the optical sheet.

Another object of the present invention is to provide a backlight unit capable of preventing physical contact between the optical sheet and the polarizing plate by preventing deformation of the optical sheet, and a liquid crystal display having the same.

Further technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following description. It can be understood.

According to an aspect of the present invention, a liquid crystal display device includes: a light source for emitting light; A bottom cover having a bottom portion and a side portion formed to extend from the bottom portion, the bottom cover accommodating the light source in an accommodation space provided by the bottom portion and the side portion; An optical sheet mounted on the bottom cover and configured to diffuse or collect light emitted from the light source; A fixing member disposed on the optical sheet and fixing a central portion of the optical sheet; A liquid crystal panel disposed on the fixing member and configured to display an image using light emitted from the light source; And a polarizing plate disposed between the fixing member and the liquid crystal panel to deflect light emitted from the light source in a specific direction, wherein the fixing member comprises: a support frame bordering an edge of the optical sheet; And a fixing part which is formed to be supported by the support frame inside the support frame and fixes the central portion of the optical sheets. The fixing member is mounted between the optical sheets and the polarizer to block contact between the optical sheets and the polarizer; The fixing part has a thickness of 0.1 mm to 1 mm.

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Here, the fixing member, a support frame for teuting the edge of the optical sheet; And a fixing part which is formed to be supported by the support frame inside the support frame and fixes the central portion of the optical sheet.

Here, the fixing part of the fixing member may be formed of a transparent material so that light emitted from the light source is transmitted.

Here, the fixing part of the fixing member may be formed to have any one of a straight, cross, X-shaped and lattice arrangement structure.

The details of other embodiments are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings.

Hereinafter, a backlight unit and a liquid crystal display having the same according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is an exploded perspective view illustrating a backlight unit according to an exemplary embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

4 and 5, the backlight unit 110 according to the embodiment of the present invention may include a light source 112, a bottom cover 114, an optical sheet 120, and a fixing member 122. In addition, the backlight unit 110 according to the embodiment of the present invention may further include a diffuser plate 128, a reflector plate 130, and a panel guide 132.

The light source 112 may be driven by a driving voltage provided from the outside to generate light, and then emit the generated light. In this case, the light emitted from the light source 112 may proceed directly toward the diffusion plate 128 or may be reflected by the reflector 130 and then travel toward the diffusion plate 128. Here, at least one light source 112 may be provided, and the number of specific light sources 112 may vary depending on the specifications of each backlight unit 110 and is not limited thereto.

The light source 112 may be a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode (Light). Emitting Diode (LED) may be used, but is not limited thereto.

The bottom cover 114 may accommodate the light source 112 and the reflector plate 130. In addition, the bottom cover 114 may sequentially seat the diffusion plate 128 and the optical sheet 120.

To this end, the bottom cover 114 may have a bottom portion 116 and a side portion 118 formed to extend from the bottom portion 116. In this case, an accommodation space may be provided by the bottom portion 116 and the side portion 118, and the light source 112 and the reflection plate 130 may be accommodated in the accommodation space. Meanwhile, the diffusion plate 128 and the optical sheet 120 may be sequentially mounted on the side portion 118. Here, the edges of each of the diffuser plate 128 and the optical sheet 120 seated on the side portion 118 are formed in a shape that borders the optical sheet 120 to be fastened to the bottom cover 114 and the panel guide 132. It can be fixed by).

The optical sheet 120 may be seated on the side portion 118 of the bottom cover 114 and may pass through the diffuser plate 128 after being emitted from the light source 112, specifically, after exiting from the light source 112. The light provided to the optical sheet 120 may be diffused or collected. Here, at least one optical sheet 120 may be provided, and the number of specific optical sheets 120 may vary depending on the specifications of each backlight unit 110, and is not limited thereto.

The fixing member 122 may be disposed above the optical sheet 120 with its edge fixed by the panel guide 132. For this reason, the fixing member 122 can fix the center part of the optical sheet 120.

The fixing member 122 may include a support frame 124 and a fixing unit 126 to fix the central portion of the optical sheet 120.

The support frame 124 may be formed to border the edge of the optical sheet 120. Here, the outer shape of the support frame 124 may be a rectangular frame shape, but this may vary depending on the shape of the optical sheet 120, but is not limited thereto.

The fixing part 126 may be formed to be supported by the support frame 124 inside the support frame 124. At this time, since the fixing part 126 may be in a state in which the support frame 124 is pulled to both sides, the fixing part 126 may not be bent upwards or sag downwards. For this reason, the fixing part 126 can fix the center part of the optical sheet 120. FIG.

When the backlight unit 110 is provided in the liquid crystal display, the area in which the fixing unit 126 is formed corresponds to the display area in which the screen is actually displayed. Therefore, the luminance unit of the liquid crystal display does not decrease due to the fixing unit 126. Should not.

For this reason, the fixing part 126 may be formed of a transparent material so that the light emitted from the light source 112 is transmitted. In this case, the transparent material may be a polymer material having mechanical properties, heat resistance, and moisture resistance, but is not limited thereto.

The fixing part 126 may be formed to have, for example, any one of a straight, cross, X and lattice arrangement. The arrangement structure of the fixing part 126 may be appropriately selected in consideration of the material and thickness of the fixing part 126 and the size, thickness and weight of the optical sheet 120.

For example, when the size of the optical sheet 120 is small, since the degree of deformation of the optical sheet 120 may be small, a straight shape may be adopted as an arrangement structure of the fixing part 126. Also, for example, when the size of the optical sheet 120 is very large, since the degree of deformation of the optical sheet 120 may be large, the fixing portion 126 may be adopted by adopting a lattice shape as an arrangement structure of the fixing portion 126. Can be formed densely.

The thickness of the fixing part 126, that is, the thickness of the fixing part 126 in the Z-axis direction may be 0.1 mm to 1 mm in consideration of the thickness of the backlight unit 110 and the degree of deformation of the optical sheet 120. have.

As such, the thickness of the fixing part 126 is 0.1 mm or more, so that the backlight unit 110 is not deformed due to the heat and / or the weight of the optical sheet 120 itself. Can be as thin as possible. In addition, the thickness of the fixing part 126 may be 1 mm or less, thereby minimizing deformation of the optical sheet 120 within the limit of thinning the backlight unit 110.

Due to the fixing member 122 described above, the optical sheet 120 may not be deformed by heat and / or its own weight. For this reason, the luminance characteristic of the light emitted from the light source 112 and emitted via the diffusion plate 128 and the optical sheet 120 may not be reduced. For this reason, the display quality deterioration of the backlight unit 110 can be prevented.

The diffuser plate 128 may be seated on the side portion 118 of the bottom cover 114 and disposed between the light source 112 and the optical sheet 120, and may diffuse upwardly the light incident from the light source 112. Permeable. This is to prevent the shape of the light source 112 from being visible through the optical sheet 120 and to further diffuse the light.

The reflective plate 130 may be accommodated in the bottom cover 114 and disposed below the light source 112, and may reflect upwardly the light emitted downward from the light emitted from the light source 112. This is to increase the utilization efficiency of the light.

6 is an exploded perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 4. FIG. 7 is a cross-sectional view taken along the line VII-VII 'of FIG. 6. Since the backlight unit of the liquid crystal display shown in FIGS. 6 and 7 is the same as the backlight unit illustrated in FIGS. 4 and 5, the same reference numerals are used to describe the same reference numerals as those of FIGS. 4 and 5. Only its features will be described.

6 and 7, the liquid crystal display 100 according to the exemplary embodiment may display an image by using electro-optic characteristics of liquid crystal molecules forming a liquid crystal layer.

To this end, the liquid crystal display 100 may include a backlight unit 110 and a liquid crystal panel 140. In addition, the liquid crystal display 100 may further include first and second polarizers 162 and 164.

The backlight unit 110 may be disposed under the liquid crystal panel 140 and may provide light to the liquid crystal panel 140.

To this end, the backlight unit 110 may include a light source 112, a bottom cover 114, an optical sheet 120, and a fixing member 122. In addition, the backlight unit 110 may further include a diffuser plate 128, a reflector plate 130, and a panel guide 132.

The liquid crystal panel 140 may be disposed above the backlight unit 110, specifically, above the fixing member 122. In this case, the liquid crystal panel 140 may be seated on the panel guide 132 and may be fixed by the top cover 170 coupled to the panel guide 132 through a screw and / or a hook.

The liquid crystal panel 140 may display an image using light provided from the backlight unit 110, specifically, light emitted from the light source 112.

To this end, the liquid crystal panel 140 may include first and second substrates 142 and 144 facing each other with the liquid crystal layer interposed therebetween.

The first substrate 142 may implement colors of the image displayed through the liquid crystal panel 140.

To this end, the first substrate 142 may include a color filter array formed of a thin film on a transparent substrate such as glass or plastic, for example, a red / green / blue color filter.

The second substrate 144 may apply a driving voltage provided from the printed circuit board 152 to the liquid crystal layer in response to a driving signal provided from the printed circuit board 152 connected to the second substrate 144 through the driving film 150. Can be.

To this end, the second substrate 144 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate of a transparent material such as glass or plastic.

Each of the first and second polarizers 162 and 164 may be mounted on each of the first and second substrates 142 and 144 of the liquid crystal panel 140. In this case, the second polarizing plate 164 may be mounted to be in contact with the optical sheet 120 by the fixing member 122. For this reason, the display quality deterioration of the liquid crystal display device 100 can be prevented. On the other hand, it is obvious that the first polarizing plate 162 is mounted so as not to be in contact with the fixing member 122.

Each of the first and second polarizers 162 and 164 may deflect the light emitted from the light source 112 in a specific direction. In this case, each of the first and second polarizers 162 and 164 may be mounted on the first and second substrates 142 and 144 such that the polarization axes of the first and second polarizers 162 and 164 are perpendicular to each other. May, but is not limited to.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

According to the present invention, the deformation of the optical sheet can be prevented through the fixing member, and physical contact between the optical sheet and the polarizing plate can be prevented. As a result, it is possible to prevent display quality deterioration of the backlight unit and the liquid crystal display including the same.

Claims (13)

delete delete delete delete delete delete A light source for emitting light; A bottom cover having a bottom portion and a side portion formed to extend from the bottom portion, the bottom cover accommodating the light source in an accommodation space provided by the bottom portion and the side portion; Optical sheets mounted on the bottom cover and configured to diffuse or collect light emitted from the light source; A fixing member disposed on top of the optical sheets; A liquid crystal panel disposed on the fixing member and configured to display an image using light emitted from the light source; And A polarizing plate disposed between the fixing member and the liquid crystal panel to deflect the light emitted from the light source in a specific direction; Wherein: A support frame bordering an edge of the optical sheet; And It is formed to be supported by the support frame inside the support frame, and includes a fixing portion for fixing the central portion of the optical sheet; The fixing member is mounted between the optical sheets and the polarizer to block contact between the optical sheets and the polarizer; The fixing part has a thickness of 0.1mm to 1mm. delete delete The method of claim 7, wherein The fixing part of the fixing member is formed of a transparent material so that the light emitted from the light source is transmitted. The method of claim 10, The transparent material is a liquid crystal display, characterized in that the polymer material. The method of claim 7, wherein The fixing part of the fixing member is formed to have any one of a straight, cross, X-shaped and lattice arrangement structure. delete

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