KR20110025493A - Backlight unit and liquid crystal display device using thereof - Google Patents

Abstract

PURPOSE: A backlight unit and a liquid crystal display device using the same are provided to supply the backlight unit of a new structure in which the light uniformity and light mixture color property are improved. CONSTITUTION: A cover bottom(110) is formed in order to include a curved surface. A substrate is arranged on a bottom side of the cover bottom. A plurality of emitting devices is installed on the substrate. The substrate includes a general printed circuit board, a flexible printed circuit board, or a metal core printed circuit board. A plurality of emitting devices includes a red, a blue, a green or a white light emitting diode.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE USING THEREOF}

Embodiments relate to a backlight unit and a liquid crystal display using the same.

Liquid crystal display devices (LCDs), which have been in the spotlight recently, have advantages such as miniaturization, light weight, and low power consumption, and as an alternative means to overcome the disadvantages of the conventional cathode ray tube (CRT). It has been attracting attention gradually and is currently used in almost all information processing devices that require a display device.

Since the liquid crystal display is not a self-luminous display, a separate light source such as a back light unit (BLU) is required. Recently, the use of light emitting diodes (LEDs) has increased as a light source used in the backlight unit.

The embodiment provides a backlight unit having a new structure and a liquid crystal display device using the same.

The embodiment provides a backlight unit with improved light uniformity.

The embodiment provides a backlight unit having improved light color mixing.

The backlight unit according to the embodiment includes a cover bottom formed such that the bottom surface includes a curved surface; A substrate disposed on a bottom surface of the cover bottom; And a plurality of light emitting devices mounted on the substrate.

According to an exemplary embodiment, there is provided a liquid crystal display, comprising: a backlight unit including a cover bottom having a bottom surface including a curved surface, a substrate disposed on the bottom surface of the cover bottom, and a plurality of light emitting devices mounted on the substrate; An optical sheet unit on the backlight unit; And a liquid crystal panel on the optical sheet portion.

The embodiment can provide a backlight unit having a new structure and a liquid crystal display device using the same.

The embodiment can provide a backlight unit with improved light uniformity.

The embodiment can provide a backlight unit having improved light mixing.

In the description of an embodiment, each layer (film), region, pattern, or structure is formed “on” or “under” a substrate, each layer (film), region, pad, or pattern. In the case where it is described as "to", "on" and "under" include both "directly" or "indirectly" formed. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

Hereinafter, a backlight unit according to embodiments will be described in detail with reference to the accompanying drawings.

<First Embodiment>

1 is a perspective view of a backlight unit according to a first embodiment, FIG. 2 is an exploded perspective view of the backlight unit, and FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 1.

1 to 3, the backlight unit includes a bottom cover 110 having a bottom surface 111 formed in a curved surface, and a light emitting module unit 120 on the bottom surface 111 of the bottom cover 110. The optical sheet unit 130 is disposed on the light emitting module unit 120.

The bottom cover 110 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding.

The bottom cover 110 may be formed in a box shape having an upper surface open so that the light emitting module unit 120 and the optical sheet unit 130 may be stored.

The bottom surface 111 of the bottom cover 110 may be formed in a curved surface.

For example, the bottom surface 111 may have a parabolic cross section extending in the first direction A. FIG. That is, when the bottom cover 110 is viewed from the first direction A, the bottom surface 111 may have a parabolic cross section. In addition, when the bottom cover 100 is viewed from the second direction B, the bottom surface 111 may have a straight cross section.

However, the shape of the bottom cover 110 and the bottom surface 111 may be variously modified according to the design of the backlight unit, but is not limited thereto.

As described above, since the bottom surface 111 of the bottom cover 110 is formed as a curved surface, when looking at the bottom cover 110 in the first direction (A), the depth of the bottom cover 110 is at the side portion Can get deeper towards the center. Accordingly, since the thickness of the side portion of the bottom cover 110 is relatively thin compared to the thickness of the center portion of the bottom cover 110, the thickness of the backlight unit may be visually thin.

The light emitting module unit 120 may be disposed on the bottom surface 111 of the bottom cover 110 formed in a curved surface.

The light emitting module unit 120 may include a substrate 121 and a plurality of light emitting devices 122 arranged in an array form on the substrate 121.

The light emitting device 122 may include a light emitting diode (LED), and the light emitting diode may be, for example, a colored light emitting diode or white light that emits light of at least one color among colors such as red, blue, and green. It may be a white diode emitting light. In addition, the colored light emitting diode may include at least one of red, blue, and green light emitting diodes, and is not limited to the number, arrangement, and emission colors of the light emitting devices 122.

The plurality of light emitting devices 122 may be arranged to have a constant pitch or may be arranged to have a non-uniform interval.

For example, the plurality of light emitting devices 122 may be densely disposed in the circumferential region of the substrate 121 rather than the middle region of the substrate 121, or conversely, the substrate (rather than the peripheral region of the substrate 121). It may be densely disposed in the middle region of 121), but is not limited thereto.

The substrate 121 includes a general printed circuit board (PCB), a metal core PCB, a flexible PCB, and the like, but is not limited thereto.

The substrate 121 may be formed to have a curved surface corresponding to the bottom surface 111 or may have good flexibility so that the light emitting module unit 120 may be seated corresponding to the bottom surface 111. It may be formed of a material that can be made. Accordingly, the substrate 121 may be disposed on the bottom surface 111 to correspond to the shape of the bottom surface 111.

The plurality of light emitting elements 122 are mounted on the substrate 121.

Since the substrate 121 has a curved surface, the plurality of light emitting devices 122 are mounted on the curved surface. That is, the plurality of light emitting devices 122 may be mounted on the substrate 121 to have different inclinations.

Therefore, the distance between the plurality of light emitting devices 122 and the optical sheet unit 130 is different depending on the mounting position of the plurality of light emitting devices 122. For example, referring to FIG. 3, the vertical distance between the light emitting devices mounted close to the side surface of the substrate 121 and the optical sheet unit 130 may be the light emitting devices mounted at the center of the substrate 121. It may be shorter than the vertical distance between the optical sheet portion 130.

For example, when the average distance between the plurality of light emitting elements 122 and the optical sheet unit 130 is k, the shortest vertical distance between the plurality of light emitting elements 122 and the optical sheet unit 130 is obtained. (h1) vs. the longest vertical distance h2 may have a relationship as shown in Equation 1.

In addition, the value h2 / h1 obtained by dividing the longest vertical distance h2 by the shortest vertical distance h1 may have a value of 1 to 5, but is not limited thereto.

h1≥k / 4, h2≤5k / 4

Since the light distribution area of the emission light of the plurality of light emitting devices 122 is increased in proportion to the square of the distance, the light emitting elements of the light emitting devices mounted near the side surface of the substrate 121 may be formed on the optical sheet part 130. The light distribution area may be smaller than the light distribution area of the optical sheet unit 130 of the emission light of the light emitting devices mounted on the center portion of the substrate 121.

In addition, since the plurality of light emitting devices 122 are mounted on the substrate 121 to have different inclinations, the emission angles of the emission light of the plurality of light emitting devices 122 may be different for each light emitting device. .

In addition, the intensity of light per unit area of the emission sheet of the plurality of light emitting devices 122 with respect to the optical sheet unit 130 may also be different for each light emitting device.

As described above, the light distribution area, emission angle, light intensity per unit area, etc. of the emission light of the plurality of light emitting devices 122 are different for each light emitting device, and thus, the plurality of light emitting devices ( The emitted light of the 122 may be effectively diffused and mixed in the optical sheet 130, etc. As a result, the light uniformity of the backlight unit may be improved to prevent the occurrence of optical mura and the like.

In addition, since the emission light of the plurality of light emitting devices 122 may be effectively mixed, the number of optical sheets included in the optical sheet unit 130 may be reduced.

Second Embodiment

Hereinafter, the backlight unit according to the second embodiment will be described in detail. However, the description overlapping with that described in the first embodiment will be omitted. The backlight unit according to the second embodiment is similar to each other except for the shape of the bottom cover of the backlight unit according to the first embodiment.

The backlight unit according to the second embodiment includes the bottom cover 110A, a light emitting module unit on the bottom surface 111A of the bottom cover 110A, and an optical sheet unit on the light emitting module unit.

4 is a perspective view of the bottom cover 110A of the backlight unit according to the second embodiment.

Referring to FIG. 4, the bottom surface 111A of the bottom cover 110A may be formed as a convex curved surface. That is, the bottom cover 110A may have a plate shape in which the bottom surface 111A protrudes convexly.

Therefore, the bottom surface 111A may have a parabolic cross section even when looking at the side surface of the bottom cover 110A in any direction.

In addition, the bottom surface 111A may increase in depth from the side portion of the bottom cover 110A to the middle portion. However, this is not limitative.

The substrate may be formed of a convex curved surface to correspond to the shape of the bottom surface 111A, or may be formed of a material that can be bent with good flexibility.

In addition, the plurality of light emitting devices may be mounted on the substrate to have different inclinations.

Therefore, since the light distribution area, the emission angle, the intensity of light per unit area, etc. of the emission light of the plurality of light emitting elements are different for each light emitting element, the emission light of the plurality of light emitting elements is determined in the optical sheet portion or the like. It may be effectively diffused and mixed, and as a result, the light uniformity of the backlight unit may be improved to prevent the occurrence of optical mura and the like.

In addition, since the emission light of the plurality of light emitting devices can be effectively mixed, it is possible to reduce the number of optical sheets included in the optical sheet portion.

Third Embodiment

Hereinafter, the backlight unit according to the third embodiment will be described in detail. However, the description overlapping with that described in the first embodiment will be omitted. The backlight unit according to the third embodiment is similar to each other except for the shape of the bottom cover of the backlight unit according to the first embodiment.

5 is a perspective view of a backlight unit according to a third embodiment.

Referring to FIG. 5, the backlight unit according to the third exemplary embodiment includes a light emitting module unit 120 and a light emitting module unit (120) on the bottom cover (110B), the bottom surface (111B) of the bottom cover (110B). The optical sheet 130 on the 120 is included.

The first surface 111B of the bottom surface of the bottom cover 110B may have a curved surface, and the second surface 111C, which is the opposite surface of the first surface 111B, may be formed flat.

Since the first surface 111B of the bottom surface is formed to have a curved surface, the light emitting module unit 120 is disposed on the curved surface, thereby improving light uniformity of the backlight unit and generating optical mura. Can be prevented. Detailed description thereof will be omitted since it is duplicated with the above description.

Since the second surface 111C of the bottom surface of the bottom cover 110B is flat, the backlight unit can be easily coupled to the top case or the like.

The liquid crystal display may be manufactured by disposing a liquid crystal panel or the like on the backlight unit according to the embodiment and arranging the support main and the top case to accommodate the liquid crystal panel.

The liquid crystal panel may include, for example, a thin film transistor substrate including a plurality of thin film transistors (TFTs), a color filter substrate disposed on the thin film transistor substrate, and a liquid crystal interposed therebetween. . In addition, one end of the thin film transistor substrate may include an integrated circuit chip (IC CHIP) for driving the liquid crystal display.

The support main and the top case may provide the liquid crystal display by accommodating and fixing the backlight unit and the liquid crystal panel. A more detailed description is omitted since it will be easily understood by those skilled in the art.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiments, which are merely exemplary and are not intended to limit the present invention, and those of ordinary skill in the art to which the present invention pertains may be provided within the scope not departing from the essential characteristics of the present embodiments. It will be appreciated that various modifications and applications are not possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a perspective view of a backlight unit according to a first embodiment.

2 is an exploded perspective view of the backlight unit.

3 is a cross-sectional view taken along the line AA ′ of FIG. 1.

4 is a perspective view of a bottom cover of the backlight unit according to the second embodiment.

5 is a perspective view of a backlight unit according to a third embodiment.

Claims (14)

A cover bottom formed such that the bottom surface includes a curved surface; A substrate disposed on a bottom surface of the cover bottom; And A backlight unit comprising a plurality of light emitting elements mounted on the substrate. The method of claim 1, The bottom surface of the cover bottom has a parabolic shape when the side surface of the cover bottom is viewed from the first direction, and the bottom surface has a straight shape when viewed from a second direction orthogonal to the first direction. The method of claim 1, The bottom surface of the cover bottom has a parabolic shape when the side surface of the cover bottom is viewed from all directions. The method of claim 1, The first surface of the bottom surface of the cover bottom is formed in a curved surface, the second surface opposite the first surface is formed in the backlight unit. The method of claim 1, The substrate is any one of a general printed circuit board, a flexible printed circuit board, a metal core printed circuit board. The method of claim 1, The substrate has a curved surface so as to correspond to the bottom surface of the cover bottom. The method of claim 1, And a thickness of at least one side portion of the cover bottom is thinner than a thickness of the central portion. The method of claim 1, The plurality of light emitting devices includes at least one of red, blue, green, or white light emitting diodes emitting red, blue, green, or white light. The method of claim 1, And a light sheet unit on the substrate and the light emitting elements. The method of claim 9, And a vertical distance between the light emitting elements mounted on the side portion of the substrate and the optical sheet portion is shorter than a vertical distance between the light emitting elements mounted on the center portion of the substrate and the optical sheet portion. The method of claim 10, The longest vertical distance between the plurality of light emitting elements and the optical sheet unit divided by the shortest vertical distance is 1 to 5; The method of claim 10, When the average vertical distance between the plurality of light emitting elements and the optical sheet portion is k, and the shortest vertical distance and the longest vertical distance between the plurality of light emitting elements and the optical sheet portion are h1 and h2, respectively, h1≥ A backlight unit that satisfies k / 4, h2 ≦ 5k / 4. The method of claim 1, The plurality of light emitting devices are disposed in the peripheral area of the substrate denser than the middle area of the substrate. A backlight unit including a cover bottom having a bottom surface including a curved surface, a substrate disposed on the bottom surface of the cover bottom, and a plurality of light emitting devices mounted on the substrate; An optical sheet unit on the backlight unit; And And a liquid crystal panel on the optical sheet portion.

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