KR100854619B1 - Backlight unit and liquid crystal display having the same - Google Patents

Abstract

A backlight unit and an LCD(Liquid Crystal Display) having the same are provided to improve display quality and to remove the necessity for a special diffusion plate and optical sheets for preventing a bright line, thereby reducing a manufacturing cost and reducing its weight and thickness. A light source(110) emits light. A light reflection member upwardly reflects light applied from the light source. The light reflection member includes first and second reflecting mirrors(122,124). Each of the first and second reflecting mirrors is formed for a part to have a curved surface. The first reflecting mirror of the light reflection member includes first to third light reflection surfaces(122a,122b,122c). The first light reflection surface is formed to face the light source. The second and third light reflection surfaces are formed to meet each other by being prolonged to be inclined from each of one side and the other side of the first light reflection surface. The first light reflection surface of the first reflecting mirror of the light reflection member is formed to have a concave curved-surface. The second and third light reflection surfaces of the first reflecting mirror of the light reflection member are formed to have a linear surface.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY HAVING THE SAME}

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

FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 1.

3 is a cross-sectional view for describing a first embodiment of the first reflector shown in FIG. 1.

4 is a cross-sectional view for describing a second exemplary embodiment of the first reflector illustrated in FIG. 1.

FIG. 5 is a cross-sectional view for describing a third embodiment of the first reflector illustrated in FIG. 1.

FIG. 6 is an exploded perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 1.

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

{Description of symbols for main parts of the drawing}

100: backlight unit 110: light source

120: light reflection member 122: first reflecting mirror

124: second reflector 200: liquid crystal display device

210: liquid crystal panel

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 that provides light to a liquid crystal panel of the liquid crystal display. Here, the liquid crystal panel may display an image using light provided from the backlight unit.

The conventional backlight unit may include a light source, a diffusion plate, an optical sheet, and a reflecting plate to provide light to the liquid crystal panel. Here, the diffusion plate and the optical sheet may be sequentially disposed on the upper portion of the light source, and the reflecting plate may be disposed below the light source.

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

The optical sheet may diffuse or condense the light emitted from the light source, specifically, the light provided to the optical sheet via the diffuser plate after being emitted from the light source. Here, at least one optical sheet may be provided, and the number of specific optical sheets may vary according to the specification of the backlight unit.

The diffusion plate may diffuse light incident from the light source upward.

The reflector may reflect upwardly the light emitted downward from the light emitted from the light source.

In the conventional backlight unit having the above-described configuration, even if the light emitted from the light source is diffused by the diffusion plate and the optical sheet, the bright line may be generated due to the difference in the amount of light according to the emission angle of the light emitted from the light source. For this reason, display quality of the backlight unit and the liquid crystal display including the same may be degraded.

The bright line can be prevented to some extent by increasing the thickness of the diffusion plate or by using a plurality of optical sheets. However, in this case, the manufacturing cost of the backlight unit and the liquid crystal display device having the same may increase, and a lot of limitations may occur in the light weight thinning of the backlight unit and the liquid crystal display device having the same.

Accordingly, an aspect of the present invention is to provide a backlight unit capable of preventing bright lines 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 device having the same that can achieve a reduction in manufacturing cost and light weight.

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. Can be understood.

A backlight unit according to an embodiment of the present invention for achieving the technical problem is a light source for emitting light; And a light reflection member for upwardly reflecting the light incident from the light source, wherein the light reflection member includes first and second reflectors, each of which is formed to have a curved surface. The first reflecting mirror of the light reflecting member may include a first light reflecting surface formed to face the light source, and second and third light reflecting surfaces formed to meet each other by extending so as to be inclined from one side and the other side of the first light reflecting surface. To include, wherein the first light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface, characterized in that each of the second and third light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a facing do.
In addition, the backlight unit according to an embodiment of the present invention for achieving the above technical problem is a light source for emitting light; And a light reflection member for upwardly reflecting the light incident from the light source, wherein the light reflection member includes first and second reflectors, each of which is formed to have a curved surface. The first reflecting mirror of the light reflecting member may include a first light reflecting surface formed to face the light source, and second and third light reflecting surfaces formed to meet each other by extending so as to be inclined from one side and the other side of the first light reflecting surface. To include, wherein the first light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface, wherein each of the second and third light reflecting surfaces of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface It is done.

On the other hand, the liquid crystal display according to an embodiment of the present invention for achieving the above technical problem is a light source for emitting light; A light reflection member for reflecting light incident from the light source upwardly; And a liquid crystal panel disposed above the light source and the light reflection member, the liquid crystal panel displaying an image using light emitted from the light source, wherein the light reflection member includes first and second reflectors. Each of the first and second reflecting mirrors is formed to have a curved surface, and the first reflecting mirror of the light reflecting member is inclined from each of the first light reflecting surface formed to face the light source and one side and the other side of the first light reflecting surface. A second light reflecting surface formed to extend to meet each other, wherein the first light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface, and the second and third light reflecting mirrors of the first reflecting mirror of the light reflecting member Each of the third light reflection surfaces is formed to have a facing.
In addition, the liquid crystal display according to an embodiment of the present invention for achieving the above technical problem is a light source for emitting light; A light reflection member for reflecting light incident from the light source upwardly; And a liquid crystal panel disposed above the light source and the light reflection member, the liquid crystal panel displaying an image using light emitted from the light source, wherein the light reflection member includes first and second reflectors. Each of the first and second reflecting mirrors is formed to have a curved surface, and the first reflecting mirror of the light reflecting member is inclined from each of the first light reflecting surface formed to face the light source and one side and the other side of the first light reflecting surface. A second light reflecting surface formed to extend to meet each other, wherein the first light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface, and the second and third light reflecting mirrors of the first reflecting mirror of the light reflecting member Each of the third light reflection surfaces is formed to have a concave curved surface.

Specific details of other embodiments are included in the detailed description and the 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.

1 is a perspective view illustrating a backlight unit according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 1.

1 and 2, the backlight unit 100 according to an exemplary embodiment of the present invention may be provided in the liquid crystal display. When the backlight unit 100 is provided in the liquid crystal display, the backlight unit 100 may provide light to the liquid crystal panel of the liquid crystal display.

To this end, the backlight unit 100 according to the embodiment of the present invention may include a light source 110 and a light reflecting member 120. In addition, the backlight unit 100 according to the embodiment of the present invention may further include a bottom cover 130. Here, the bottom cover 130 may accommodate the light source 110 and the light reflecting member 120.

The light source 110 may be driven by a driving voltage provided from the outside to generate light, and then emit the generated light. In this case, some of the light emitted from the light source 110 may be directly emitted upward, and the remaining light may be reflected by the light reflecting member 120 and then emitted upward.

At least one light source 110 may be provided, and the number of light sources 110 may vary depending on the specification of the backlight unit 100, and is not limited thereto.

The light source 110 may include, for example, a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode. Any one of (Light Emitting Diode: LED) may be used, but is not limited thereto.

The light reflecting member 120 may reflect light incident thereon upward from the light emitted from the light source 110.

To this end, the light reflection member 120 may include first and second reflectors 122 and 124. Here, one side and the other side of each of the first and second reflectors 122 and 124 may be connected to each other such that the first and second reflectors 122 and 124 are formed in an integrated form.

The first reflector 122 may be formed so that at least a part thereof has a curved surface. Here, the curved surface may mean any one of a spherical surface, a parabolic surface, and an elliptic surface. Hereinafter, the curved surface may have the same meaning.

Specifically, the first reflector 122 may include first to third light reflection surfaces 122a, 122b, and 122c, and at least one of the first to third light reflection surfaces 122a, 122b, and 122c. It may be formed to have a curved surface. Here, the first light reflection surface 122a may be formed to face the light source 110. In addition, each of the second and third light reflection surfaces 122b and 122c may be formed to meet each other by extending inclined from one side and the other side of the first light reflection surface 122a. In this case, when the second and third light reflection surfaces 122b and 122c are formed to be inclined upward, the cross-section of the first reflector 122 may have a hat shape.

The first reflector 122 may be disposed above the light source 110. For this reason, some of the light emitted from the light source 110, that is, light emitted from the light source 110 in a vertical direction and / or a similar direction does not go straight, but is a first light reflection surface of the first reflector 122. The first reflection may be performed at 122a in the direction of the second reflector 124. In this case, the light primarily reflected by the first light reflection surface 122a may be secondarily reflected upward from the second reflector 124.

Through this, bright lines of the backlight unit 100 may be prevented. As a result, display quality of the backlight unit 100 and the liquid crystal display including the same may be improved. In order to prevent such bright lines, the backlight unit 100 according to the exemplary embodiment of the present invention may not include a separate diffusion plate and an optical sheet. Therefore, the manufacturing cost of each of the backlight unit 100 and the liquid crystal display device having the same according to the embodiment of the present invention can be lowered, and the weight reduction of the backlight unit 100 and the liquid crystal display device having the same can be achieved. can do.

However, although the bright line may be prevented through the first reflector 122 disposed above, dark lines may occur in a region where the light source 110 is located due to the first reflector 122. This can be prevented through the light reflection of the second and third light reflection surfaces 122b and 122c of the first reflector 122.

Specifically, some of the light emitted from the light source 110 to be inclined upwardly is first-order in the direction of the second and third light reflection surfaces 122b and 122c of the first reflector 122 at the second reflector 124. Can be reflected. In this case, the light primarily reflected by the second reflector 124 may be uniformly reflected upward from each of the second and third light reflection surfaces 122b and 122c.

As described above, the first light reflecting surface 122a of the first reflecting mirror 122 is formed to face the light source 110 so that the light emitted from the light source 110 in a vertical direction and / or a similar direction is second to the second light reflecting surface 122a. Primary reflection may be made in the direction of the reflector 124. In this case, the first reflector 122 may be formed to have a curved surface for uniform light reflection. However, since the light emitted from the light source 110 may not be directly incident on the second and third light reflection surfaces 122b and 122c of the first reflecting mirror 122, the second and third light reflection surfaces 122b and 122c. The shape of may vary. This will be described in more detail with reference to each of FIGS. 3 to 5.

3 is a cross-sectional view for describing a first embodiment of the first reflector shown in FIG. 1.

Referring to FIG. 3, the first light reflecting surface 122a of the first reflecting mirror 122 may be formed to have a concave curved surface. On the other hand, the second and third light reflection surfaces 122b and 122c of the first reflector 122 may be formed to have a facing. In this case, the second and third light reflection surfaces 122b and 122c may be symmetrically formed with respect to the first light reflection surface 122a. This is to ensure luminance uniformity through the second and third light reflection surfaces 122b and 122c which are symmetric to each other.

When the second and third light reflection surfaces 122b and 122c of the first reflecting mirror 122 are formed to have a facing and meet each other, an angle is formed between the second and third light reflection surfaces 122b and 122c. Can be. In this case, the angle θ between the second and third light reflection surfaces 122b and 122c may be 60 to 150 degrees. This is to prevent a bright line or a dark line when the angle between the second and third light reflection surfaces 122b and 122c is out of the range of the angle θ.

4 is a cross-sectional view for describing a second exemplary embodiment of the first reflector illustrated in FIG. 1.

Referring to FIG. 4, the first light reflecting surface 122a of the first reflecting mirror 122 may be formed to have a concave curved surface. In addition, the second and third light reflection surfaces 122b and 122c of the first reflector 122 may be formed to have a concave curved surface. In this case, the second and third light reflection surfaces 122b and 122c may be symmetrically formed with respect to the first light reflection surface 122a.

FIG. 5 is a cross-sectional view for describing a third embodiment of the first reflector illustrated in FIG. 1.

Referring to FIG. 5, the first light reflecting surface 122a of the first reflecting mirror 122 may be formed to have a concave curved surface. On the other hand, the second and third light reflection surfaces 122b and 122c of the first reflector 122 may be formed to have convex curved surfaces. In this case, the second and third light reflection surfaces 122b and 122c may be symmetrically formed with respect to the first light reflection surface 122a.

Referring back to FIGS. 1 and 2, the second reflector 124 may be formed such that at least a portion thereof has a curved surface.

For example, the second reflector 124 may include fourth and fifth light reflecting surfaces 124a and 124b, and at least one of the fourth and fifth light reflecting surfaces 124a and 124b has a curved surface. Can be formed. Here, the fourth light reflection surface 124a may be formed to have a shape of a curved surface inclined from the lower portion of the light source 110 to the upper direction. In addition, the fifth light reflection surface 124b may be formed to extend upward from one side and the other side of the fourth light reflection surface 124a and may be formed as one of a facing surface and a curved surface. For this reason, the second reflector 124 may be formed to enclose a portion of the light source 110 in a shape of accommodating the light source 110.

Specifically, the fourth light reflection surface 124a of the second reflector 124 may be formed to have a concave curved surface. In this case, the light primarily reflected by the first light reflection surface 122a of the first reflector 122 may be converted into parallel light or quasi-parallel light by the secondary reflection of the second reflector 124. For this reason, the luminance uniformity of the backlight unit 100 may be secured.

The radius of curvature of the fourth light reflection surface 124a of the second reflector 124 may be 1 mm to 1 m. As described above, the radius of curvature of the fourth light reflection surface 124a is 1 mm or more, so that the first reflecting mirror 122 can be formed to accommodate the light source 110 in consideration of the diameter of the light source 110. The first light reflected from the first light reflecting surface 122a of) may be converted into parallel light or quasi-parallel light through the second reflection of the second reflector 124. In addition, by making the radius of curvature of the fourth light reflection surface 124a less than or equal to 1 m, the secondary reflection of the second reflection mirror 124 is reflected by the light reflected primarily by the first light reflection surface 122a of the first reflection mirror 122. The second reflector 124 may be formed in a shape for accommodating the light source 110 in consideration of the distance between the light sources 110 within the limits that can be converted into parallel light or quasi-parallel light.

6 is an exploded perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 1. FIG. 7 is a cross-sectional view taken along the line VII-VII 'of FIG. 6. Since the backlight unit illustrated in FIGS. 6 and 7 is the same as the backlight unit illustrated in FIG. 1, the same reference numerals will be used to describe the same reference numerals, and description thereof will not be repeated.

6 and 7, the liquid crystal display 200 according to the exemplary embodiment of the present invention may display an image by using the electro-optical characteristics of the liquid crystal.

To this end, the liquid crystal display 200 according to the exemplary embodiment of the present invention may include a backlight unit 100 and a liquid crystal panel 210.

The backlight unit 100 may be disposed under the liquid crystal panel 210 and may provide light to the liquid crystal panel 210.

To this end, the backlight unit 100 may include a light source 110 and a light reflecting member 120. In addition, the backlight unit 100 may further include a bottom cover 130.

The liquid crystal panel 210 may be formed in a substantially rectangular frame shape and may be seated on the panel guide 212 coupled to the bottom cover 130. In this case, the liquid crystal panel 210 may be formed in a substantially rectangular frame shape and fixed on the panel guide 212 by the top cover 214 formed to surround the edge of the liquid crystal panel 210.

The liquid crystal panel 210 may display an image using light provided from the backlight unit 100, that is, light emitted from the light source 110.

To this end, the liquid crystal panel 210 may include a color filter substrate 220 and a thin film transistor substrate 230 that face each other with the liquid crystal interposed therebetween.

The color filter substrate 220 may implement colors of the image displayed through the liquid crystal panel 210.

To this end, the color filter substrate 220 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. Here, the first polarizer may be attached to the outer surface of the color filter substrate 220.

The thin film transistor substrate 230 may apply a driving voltage provided from the printed circuit board 232 to the liquid crystal through the driving film 234 in response to a driving signal provided from the printed circuit board 232 on which the driving circuit components are mounted. Can be.

To this end, the thin film transistor substrate 230 may include a thin film transistor, a pixel electrode, and a common electrode formed of a thin film on another transparent substrate such as glass or plastic. Here, the common electrode may be formed on the color filter substrate 220. Here, the second polarizer may be attached to the outer surface of the thin film transistor substrate 230.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. I can understand that.

Therefore, since the embodiments described above are provided to completely inform the scope of the invention to those skilled in the art, it should be understood that they are exemplary in all respects and not limited. The invention is only defined by the scope of the claims.

According to the present invention, it is possible to prevent bright lines of the backlight unit and to improve display quality of the backlight unit and the liquid crystal display including the same. In addition, since a separate diffusion plate and an optical sheet may not be provided to prevent the bright lines, manufacturing costs may be reduced, and a lightweight thin backlight unit and a liquid crystal display may be manufactured.

Claims (26)

A light source for emitting light; And Light reflecting member for reflecting light incident from the light source upwards Including; The light reflecting member includes first and second reflecting mirrors, each of the first and second reflecting mirrors is partially formed to have a curved surface, and the first reflecting mirror of the light reflecting member includes: A first light reflection surface formed to face the light source, and second and third light reflection surfaces formed to meet each other by extending to be inclined from one side and the other side of the first light reflection surface, And a first light reflecting surface of the first reflecting mirror of the light reflecting member is formed to have a concave curved surface, and each of the second and third light reflecting surfaces of the first reflecting mirror of the light reflecting member is formed to have a facing. delete The method of claim 1, And a curved surface of each of the first and second reflecting mirrors of the light reflecting member is one of a spherical surface, a parabolic surface, and an ellipsoidal surface. The method of claim 1, And a first reflecting mirror of the light reflecting member is disposed above the light source. The method of claim 1, The cross-section of the first reflecting mirror of the light reflecting member has a hat shape. The method of claim 1, The second reflecting mirror of the light reflecting member is formed in a shape for receiving the light source. The method of claim 1, The radius of curvature of the curved surface of the second reflector of the light reflection member is 1mm to 1m, characterized in that. delete delete delete A light source for emitting light; And Light reflecting member for reflecting light incident from the light source upwards Including; The light reflecting member includes first and second reflecting mirrors, each of the first and second reflecting mirrors is partially formed to have a curved surface, and the first reflecting mirror of the light reflecting member includes: A first light reflection surface formed to face the light source, and second and third light reflection surfaces formed to meet each other by extending to be inclined from one side and the other side of the first light reflection surface, A first light reflection surface of the first reflector of the light reflection member is formed to have a concave curved surface, and each of the second and third light reflection surfaces of the first reflector of the light reflection member is formed to have a concave curved surface . delete The method according to claim 1 or 11, wherein The angle formed by the second and third light reflection surface of the first reflecting mirror of the light reflection member is 60 to 150 degrees. A light source for emitting light; A light reflection member for reflecting light incident from the light source upwardly; And A liquid crystal panel disposed on the light source and the light reflection member and displaying an image by using light emitted from the light source; Including; The light reflecting member includes first and second reflecting mirrors, each of the first and second reflecting mirrors is partially formed to have a curved surface, and the first reflecting mirror of the light reflecting member includes: A first light reflection surface formed to face the light source, and second and third light reflection surfaces formed to meet each other by extending to be inclined from one side and the other side of the first light reflection surface, The first light reflection surface of the first reflector of the light reflection member is formed to have a concave curved surface, and each of the second and third light reflection surfaces of the first reflector of the light reflection member is formed to have a facing. . delete The method of claim 14, And a curved surface of each of the first and second reflecting mirrors of the light reflecting member is one of a spherical surface, a parabolic surface, and an elliptic surface. The method of claim 14, And a first reflecting mirror of the light reflecting member is disposed above the light source. The method of claim 14, And a cross section of the first reflecting mirror of the light reflecting member has a hat shape. The method of claim 14, And a second reflecting mirror of the light reflecting member is formed to receive the light source. The method of claim 14, The radius of curvature of the curved surface of the second reflecting mirror of the light reflection member is 1mm to 1m. delete delete delete A light source for emitting light; A light reflection member for reflecting light incident from the light source upwardly; And A liquid crystal panel disposed on the light source and the light reflection member and displaying an image by using light emitted from the light source; Including; The light reflecting member includes first and second reflecting mirrors, each of the first and second reflecting mirrors is partially formed to have a curved surface, and the first reflecting mirror of the light reflecting member includes: A first light reflection surface formed to face the light source, and second and third light reflection surfaces formed to meet each other by extending to be inclined from one side and the other side of the first light reflection surface, The first light reflection surface of the first reflector of the light reflection member is formed to have a concave curved surface, and each of the second and third light reflection surfaces of the first reflector of the light reflection member is formed to have a concave curved surface. Device. delete The method of claim 14 or 24, And an angle formed by the second and third light reflection surfaces of the first reflector of the light reflection member is in a range of 60 degrees to 150 degrees.

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