Backlight unit and display device including the same

This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2017-0167568, filed on Dec. 7, 2017, the disclosure of which is incorporated by reference herein in its entirety.

Exemplary embodiments of the present inventive concept relate to a backlight unit, and a display device including the same.

A liquid crystal display (LCD) device includes a liquid crystal layer disposed between two glass substrates, and displays information by applying voltages to electrodes disposed on or below the glass substrates.

LCD devices are light-receiving devices that cannot emit light themselves, but rather, display images by controlling the transmittance of light incident thereon. LCD devices utilize a backlight unit to apply light to a display panel.

A backlight unit may be classified as a direct-type backlight unit or an edge-type backlight unit depending on the arrangement of light sources disposed thereon. An edge-type backlight unit has a structure in which light sources are disposed on one side of a light guide plate, and a direct-type backlight unit has a structure in which light sources are disposed below a display panel. The use of edge-type backlight units has been increasing as display devices become thinner and more lightweight.

Exemplary embodiments of the present inventive concept provide an edge-type backlight unit having a structure in which a light guide plate is stably fixed, and a display device including the backlight unit.

According to an exemplary embodiment of the present inventive concept, a backlight unit includes a light guide plate (LGP), a housing that receives the LGP, and a first LGP guide member coupled to the housing. The housing includes a bottom surface, a first sidewall, and a second sidewall. The first and second sidewalls are connected to edges of the bottom surface, are disposed adjacent to each other, and are spaced apart from each other. A first corner of the bottom surface is disposed between the first and second sidewalls, and the first LGP guide member is disposed in a gap between the first and second sidewalls.

According to an exemplary embodiment of the present inventive concept, a display device includes a backlight unit and a display panel disposed on the backlight unit. The backlight unit includes a light guide plate (LGP), a housing that receives the LGP, and a first LGP guide member coupled to the housing. The housing includes a bottom surface, a first sidewall, and a second sidewall. The first and second sidewalls are connected to edges of the bottom surface, the first and second sidewalls are disposed adjacent to each other and are spaced apart from each other, and a first corner of the bottom surface is disposed between the first and second sidewalls. The first LGP guide member is disposed in a gap between the first and second sidewalls.

According to the aforementioned and other exemplary embodiments of the present inventive concept, a light guide plate is stably supported, and as a result, a backlight unit and a display device with improved durability is provided.

In addition, since light guide plate supporting members are disposed at the corners of a housing, a backlight unit and a display device having a narrow bezel are provided.

The above and other features of the present inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a display device according to an exemplary embodiment of the present inventive concept.

FIG. 2 is a plan view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 3 is a cross-sectional view taken along line III-III′ of FIG. 1 according to an exemplary embodiment of the present inventive concept.

FIG. 4 is a cross-sectional view taken along line IV-IV′ of FIG. 1 according to an exemplary embodiment of the present inventive concept.

FIG. 5 is an enlarged perspective view of area A of FIG. 2 according to an exemplary embodiment of the present inventive concept.

FIG. 6 is an enlarged perspective view of area B of FIG. 2 according to an exemplary embodiment of the present inventive concept.

FIG. 7 is a cross-sectional view taken along line VII-VII′ of FIG. 2 according to an exemplary embodiment of the present inventive concept.

FIGS. 8 and 9 are plan views of backlight units according to exemplary embodiments of the present inventive concept.

FIG. 10 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 11 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 12 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 13 is a cross-sectional view taken along line XIII-XIII′ of FIG. 12 according to an exemplary embodiment of the present inventive concept.

Exemplary embodiments of the present inventive concept will be described more fully hereinafter with reference to the accompanying drawings. Like reference numerals may refer to like elements throughout the accompanying drawings.

It will be understood that when a component, such as a film, a region, a layer, or an element, is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another component, it can be directly on, connected, coupled, or adjacent to the other component, or intervening components may be present. It will also be understood that when a component is referred to as being “between” two components, it can be the only component between the two components, or one or more intervening components may also be present.

Spatially relative terms, such as “beneath”, “below”, “lower”, “under”, “above”, “upper”, etc., may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary terms “below” and “under” can encompass both an orientation of above and below.

It will be understood that the terms “first,” “second,” “third,” etc. are used herein to distinguish one element from another, and the elements are not limited by these terms. Thus, a “first” element in an exemplary embodiment may be described as a “second” element in another exemplary embodiment.

Herein, when two or more elements or values are described as being substantially the same as or about equal to each other, it is to be understood that the elements or values are identical to each other, indistinguishable from each other, or distinguishable from each other but functionally the same as each other as would be understood by a person having ordinary skill in the art. It will be further understood that when two components or directions are described as extending substantially parallel or perpendicular to each other, the two components or directions extend exactly parallel or perpendicular to each other, or extend approximately parallel or perpendicular to each other within a measurement error as would be understood by a person having ordinary skill in the art. Further, it is to be understood that while parameters may be described herein as having “about” a certain value, according to exemplary embodiments, the parameter may be exactly the certain value or approximately the certain value within a measurement error as would be understood by a person having ordinary skill in the art.

FIG. 1 is an exploded perspective view of a display device according to an exemplary embodiment of the present inventive concept.

Referring to FIG. 1 , in an exemplary embodiment, a display device 1 includes a display panel 10 and a backlight unit 20 . The backlight unit 20 provides light to the display panel 10 . The backlight unit 20 may include a light guide plate (LGP) 100 , a light source unit 200 , one or more optical sheets 300 , a reflective sheet 400 , and a housing 500 . The housing 500 accommodates the light guide plate 100 , the light source unit 200 , the optical sheets 300 , and the reflective sheet 400 . Unless specified otherwise, the terms “upper”, “top”, and “above” refer to a display surface's side, and the terms “lower”, “bottom”, and “below” refer to the opposite side of the display surface.

The display panel 10 displays an image. For example, the display panel 10 may be a liquid crystal display (LCD) panel. The display device 1 will hereinafter be described as being a flat display device having an LCD panel as the display panel 10 as an example. However, exemplary embodiments of the present inventive concept are not limited thereto. For example, various types of display panels other than an LCD panel, such as an electro-wetting display panel, an electrophoretic display panel, and a micro-electro-mechanical system (MEMS) display panel, may also be applicable to the display device 1 according to exemplary embodiments of the inventive concept.

The backlight unit 20 is disposed below the display panel 10 . The backlight unit 20 provides light to the display panel 10 . The display panel 10 displays an image by receiving is light from the backlight unit 20 .

The backlight unit 20 will hereinafter be described with reference to FIGS. 2 through 4 .

FIG. 2 is a plan view of a backlight unit according to an exemplary embodiment of the present inventive concept. For convenience of illustration, the optical sheets 300 of FIG. 1 are not illustrated in FIG. 2 . FIG. 3 is a cross-sectional view taken along line III-III′ of FIG. 1 according to an exemplary embodiment of the present inventive concept. FIG. 4 is a cross-sectional view taken along line IV-IV′ of FIG. 1 according to an exemplary embodiment of the present inventive concept.

Referring to FIGS. 1 through 4 , in an exemplary embodiment, the housing 500 includes a body portion 510 and light guide plate guide members 520 , which are coupled to corners 510 r of the body portion 510 . The body portion 510 includes a bottom surface 510 B, a plurality of sidewalls 510 S, which are connected to the edges of the bottom surface 510 B, and protruding portions 510 P, which protrude outwardly from the sidewalls 510 S. In an exemplary embodiment, the body portion 510 includes first and third sidewalls 510 S 1 and 510 S 3 and second and fourth sidewalls 510 S 2 and 510 S 4 , which intersect the first and third sidewalls 510 S 1 and 510 S 3 and are opposite to the first and third sidewalls 510 S 1 and 510 S 3 , respectively. In an exemplary embodiment, the sidewalls 510 S may be bent, and may extend from the bottom surface 510 B. In this exemplary embodiment, the sidewalls 510 S and the bottom surface 510 B may be integrally formed without any connecting portions disposed therebetween.

In an exemplary embodiment, the first through fourth sidewalls 510 S 1 through 510 S 4 of the body portion 510 are not connected to one another and are spaced apart from one another. For example, the first through fourth sidewalls 510 S 1 through 510 S 4 , which are adjacent to one another with the corners 510 r of the body portion 510 disposed therebetween, may be spaced apart from one another. For example, in an exemplary embodiment, the first sidewall 510 S 1 is connected to the corresponding edge of the bottom surface 510 B, but is not disposed at the corners 510 r , so that the edges of the bottom surface 510 B are exposed at the corners 510 r . Also, in an exemplary embodiment, the second, third, and fourth sidewalls 510 S 2 , 510 S 3 , and 510 S 4 are connected to the corresponding edges of the bottom surface 510 B, but are not disposed at the corners 510 r . The corners 510 r where the sidewalls 510 S are not disposed provide spaces in which to arrange the light guide plate guide members 520 . The light guide plate guide members 520 will be described in further detail below.

In an exemplary embodiment, the body portion 510 includes the protruding portions 510 P, which protrude outwardly from the sidewalls 510 S. However, exemplary embodiments of the present inventive concept are not limited thereto. For example, in exemplary embodiments, the protruding portions 510 r may be disposed only at the first and third sidewalls 510 S 1 and 510 S 3 or at the second and fourth sidewalls 510 S 2 and 510 S 4 . In an exemplary embodiment, housing coupling members 30 are disposed on the protruding portions 510 P and fix the display panel 10 . For example, the display device 1 may further include the housing coupling members 30 , which are disposed between the housing 500 and the display panel 10 , and which fix the display panel 10 to the housing 500 .

The housing coupling members 30 may include a polymer resin or an adhesive tape. In exemplary embodiments, the housing coupling members 30 may include a light-absorbing material, such as a black pigment or dye, or a reflective material, and may thus perform a light-blocking function that prevents light from leaking to unintended places. Thus, in addition to fixing the display panel 10 to the housing 500 , in exemplary embodiments, the housing coupling members also improve the optical efficiency of the display device 1 by preventing light from leaking to a region other than a display region.

The protruding portions 510 P may have a planar shape and may protrude outwardly from the sidewalls 510 S. The ends of the protruding portions 510 P may be disposed on the inner sides of the sides of the display panel 10 . For example, in a plan view, the protruding portions 510 P may be hidden from view by the display panel 10 . In this case, the bezel area of the display device 1 is reduced, and as a result, a narrow bezel is realized.

However, the shape of the protruding portions 510 P is not particularly limited. For example, each of the protruding portions 510 P may have a first plane that extends outwardly from one of the sidewalls 510 S, and a second plane that is bent and extends from the first plane toward the bottom surface 510 B. The second plane may have substantially the same height as the sidewalls 510 S. In this case, the first plane is supported by the second plane. Also, since the load of the display panel 10 is distributed, the display panel 10 is stably fixed.

In an exemplary embodiment, the sidewalls 510 S of the body portion 510 are thick enough to support the display panel 10 . In this case, the protruding portions 510 P may not be provided, and the housing coupling members 30 , instead of the protruding portions 510 P, may be disposed on the top surfaces of the sidewalls 510 S of the body portion 510 .

In exemplary embodiments, the light guide plate 100 is accommodated in an inner space defined by the body portion 510 of the housing 500 and the light guide plate guide members 520 .

The light guide plate 100 guides the path of light. The light guide plate 100 may be substantially in the shape of a polygonal column. The light guide plate 100 may have a rectangular shape in a plan view. However, exemplary embodiments of the present inventive concept are not limited thereto. In an exemplary embodiment, the light guide plate 100 may be in the shape of a hexagonal column whose planar shape is rectangular, and may have a top surface 100 a , a bottom surface 100 b , and four side surfaces 100 s.

In exemplary embodiments, the light guide plate 100 further includes corner inclined surfaces 100 r , which are disposed between the four side surfaces 100 s . The corner inclined surfaces 100 r may also be referred to herein as notches of the light guide plate 100 . A pair of adjacent side surfaces 100 s of the light guide plate 100 meet both edges of one corner inclined surface 100 r . The corner inclined surfaces 100 r are inclined with respect to the side surfaces 100 s of the light guide plate 100 . The angle that the corner inclined surfaces 100 r form with the side surfaces 100 s may be an obtuse angle. For example, the corner inclined surfaces 100 r may form an angle of about 135° with the side surfaces 100 s.

The corner inclined surfaces 100 r reduce the sharpness of the edges of the light guide plate 100 , and may thus prevent the light guide plate 100 from being damaged by external impact. The corner inclined surfaces 100 r may be flat, or may be partially curved.

The corner inclined surfaces 100 r of the light guide plate 100 may be fixed by the light guide plate guide members 520 of the housing 500 . The corner inclined surfaces 100 r of the light guide plate 100 are illustrated as being placed in contact with the light guide plate guide members 520 . However, exemplary embodiments the present inventive concept are not limited thereto. For example, in exemplary embodiments, the corner inclined surfaces 100 r of the light guide plate 100 may be a predetermined distance apart from the light guide plate guide members 520 . The side surfaces 100 s of the light guide plate 100 may be a predetermined distance apart from the sidewalls 510 S of the housing 500 . The light guide plate 100 may expand in a high-temperature environment. Thus, if there is no space for the expansion of the light guide plate 100 , the light guide plate 100 may warp or crack. Alternatively, if the light guide plate 100 is a predetermined distance apart from the housing 500 so that a sufficient space is secured between the light guide plate 100 and the housing 500 , as is the case according to exemplary embodiments of the present inventive concept, the light guide plate 100 may not be damaged even if it expands.

The light guide plate 100 may include an inorganic material. For example, the light guide plate 100 may be formed of glass. However, exemplary embodiments of the present inventive concept are not limited thereto.

The light source unit 200 may be disposed adjacent to at least one side surface 100 s of the light guide plate 100 . For example, as illustrated in FIGS. 1 through 3 , in an exemplary embodiment, a plurality of light-emitting diodes (LEDs) 210 mounted on a printed circuit board (PCB) 220 are disposed on a side surface 100 s corresponding to one long side of the light guide plate 100 . However, exemplary embodiments of the present inventive concept are not limited thereto. For example, in exemplary embodiments, the LEDs 210 are disposed adjacent to a pair of opposite side surfaces 100 s corresponding to both long sides of the light guide plate 100 , a side surface 100 s corresponding to one short side of the light guide plate 100 , or a pair of opposite side surfaces 100 s corresponding to both short sides of the light guide plate 100 .

The light source unit 200 may be fixed to one sidewall 510 S of the body portion 510 of the housing 500 . For example, the light source unit 200 may be fixed to the third sidewall 510 S 3 of the housing 500 .

In an exemplary embodiment, the LEDs 210 may be top-emitting LEDs emitting light through the top surfaces thereof, as illustrated in FIG. 1 . In this exemplary embodiment, the PCB 220 may be disposed on the third sidewall 510 S 3 of the housing 500 . However, exemplary embodiments of the present inventive concept are not limited thereto. For example, in an exemplary embodiment, the LEDs 210 may be side-emitting LEDs emitting light through the sides thereof. In this exemplary embodiment, the PCB 220 may be disposed on the bottom surface 510 B of the housing 500 .

The light source unit 200 may be a predetermined distance from the light guide plate 100 . By providing a space between the light source unit 200 and the light guide plate 100 , the light guide plate 100 is prevented from being damaged by heat generated by the light source unit 200 .

One or more optical sheets 300 may be further provided on the top surface 100 a of the light guide plate 100 . The optical sheets 300 may be disposed between the display panel 10 and the light guide plate 100 . The optical sheets 300 may be mounted on the light guide plate guide members 520 , as described in further detail below.

The optical sheets 300 may include, for example, a prism sheet, a diffusion sheet, a is micro-lens sheet, a lenticular sheet, a polarizing sheet, a reflective polarizing sheet, or a phase different sheet. The display device 1 may include a plurality of optical sheets 300 that are of the same type or of different types. In a case in which the plurality of optical sheets 300 are used, the plurality of optical sheets 300 may be disposed to overlap with one another, and the corners of each of the plurality of optical sheets 300 may be mounted on the light guide plate guide members 520 .

The reflective sheet 400 may be disposed below the light guide plate 100 . The reflective sheet 400 may be disposed between the bottom surface 100 b of the light guide plate 100 and the bottom surface 510 B of the housing 500 .

The reflective sheet 400 may include a reflective film or a reflective coating layer. The optical sheet 400 reflects light emitted from the bottom surface 100 b of the light guide plate 100 back into the light guide plate 100 .

The light guide plate guide members 520 will hereinafter be described with reference to FIGS. 2 and 5 through 7 .

FIG. 5 is an enlarged perspective view of area A of FIG. 2 according to an exemplary embodiment of the present inventive concept. FIG. 6 is an enlarged perspective view of area B of FIG. 2 according to an exemplary embodiment of the present inventive concept. FIG. 7 is a cross-sectional view taken along line VII-VII′ of FIG. 2 according to an exemplary embodiment of the present inventive concept.

Referring to FIGS. 2 and 5 through 7 , in an exemplary embodiment, the light guide plate guide members 520 are coupled to the corners 510 r of the body portion 510 .

In an exemplary embodiment, the light guide plate guide members 520 are formed at the body portion 510 through outsert molding using a mold material. In this exemplary embodiment, the light guide plate guide members 520 may be coupled to the body portion 510 without the aid of an additional adhesive member. The light guide plate guide members 520 may include, for example, polycarbonate (PC) and glass fiber that are mixed at a predetermined ratio.

In an exemplary embodiment, the light guide plate guide members 520 include first through fourth light guide plate guide members 521 through 524 . The first light guide plate guide member 521 is disposed at the corner 510 r between the first and second sidewalls 510 S 1 and 510 S 2 . The second light guide plate guide member 522 is disposed at the corner 510 r between the second and third sidewalls 510 S 2 and 510 S 3 . The third light guide plate guide member 523 is disposed at the corner 510 r between the third and fourth sidewalls 510 S 3 and 510 S 4 . The fourth light guide plate guide member 524 is disposed at the corner 510 r between the fourth and first sidewalls 510 S 4 and 510 S 1 .

The first through fourth light guide plate guide members 521 through 524 have similar shapes and functions, but the second and third light guide plate guide members 522 and 523 differ from the first and fourth light guide plate guide members 521 and 524 in that they are disposed adjacent to the third sidewall 510 S 3 . Thus, the shape of the first light guide plate guide member 521 may be symmetrical with the shape of the fourth light guide plate guide member 524 , and the shape of the second light guide plate guide member 522 may be symmetrical with the shape of the third light guide plate guide member 523 .

The light guide plate guide members 520 will hereinafter be described using the first light guide plate guide member 521 as an example, and for convenience of explanation, descriptions of features that the light guide plate guide members 520 all share in common will be omitted or simplified.

In an exemplary embodiment, the first light guide plate guide member 521 includes coupling portions 521 C, which are fixed to the body portion 510 of the housing 500 , and a guide inclined surface 521 r , which prevents the movement of the light guide plate 100 .

For example, in an exemplary embodiment, the first light guide plate guide member 521 includes the coupling portions 521 C, which are coupled to the ends of the first and second sidewalls 510 S 1 and 510 S 2 . The shape of the coupling portions 521 C may correspond to the shape of the ends of the first and second sidewalls 510 S 1 and 510 S 2 . For example, the coupling portions 521 C may be formed to have stepped portions that fit stepped portions formed at the ends of the first and second sidewalls 510 S 1 and 510 S 2 .

In an exemplary embodiment, the inner sides of the coupling portions 521 C are substantially aligned with the inner sides of the first and second sidewalls 510 S 1 and 510 S 2 . Thus, the first light guide plate guide member 521 does not protrude inwardly beyond the first and second sidewalls 510 S 1 and 510 S 2 , and as a result, an unnecessary waste of space is prevented. For example, if the first light guide plate guide member 521 protrudes inwardly beyond the first and second sidewalls 510 S 1 and 510 S 2 or is disposed on the inside of the first and second sidewalls 510 S 1 and 510 S 2 , a space for the light guide plate 100 may be reduced, and as a result, the bezel area of the display device 1 may be increased. Alternatively, if the first light guide plate guide member 521 is disposed in the gap between the first and second sidewalls 510 S 1 and 510 S 2 and does not protrude inwardly beyond the first and second sidewalls 510 S 1 and 510 S 2 , as is the case according to exemplary embodiments of the present inventive concept, a large space (e.g., as large a space as possible) may be secured for the light guide plate 100 , and as a result, the bezel area of the display device 1 may be reduced.

In an exemplary embodiment, the first light guide plate guide member 521 includes the guide inclined surface 521 r , which corresponds to one of the corner inclined surfaces 100 r of the light guide plate 100 . As described above, the guide inclined surface 521 r may be disposed adjacent to the corresponding corner inclined surface 100 r.

In an exemplary embodiment, the guide inclined surface 521 r is disposed at an inclination with respect to the coupling portions 521 C. The inclination angle of the guide inclined surface 521 r corresponds to the inclination angle of the corner inclined surfaces 100 r of the light guide plate 100 . For example, in an exemplary embodiment in which the inclination angle of each of the corner inclined surfaces 100 r with respect to the side surfaces 100 s is about 135°, the inclination angle of the guide inclined surface 521 r with respect to the inner sides of the coupling portions 521 C may be about 45°. For example, the guide inclined surface 521 r of the first light guide plate guide member 521 may be disposed substantially in parallel to the corner inclined surface 100 r that the first light guide plate guide member 521 is disposed adjacent to.

The inclined surface 521 r of the first light guide plate guide member 521 prevents the movement of the light guide plate 100 in the lengthwise and widthwise directions of the light guide plate 100 . For example, the inclined surface 521 r of the first light guide plate guide member 521 may be disposed to intersect the light guide plate 100 in the lengthwise and widthwise directions of the light guide plate 100 . Accordingly, the first light guide plate guide member 521 prevents the movement of the light guide plate 100 in both the lengthwise and widthwise directions of the light guide plate 100 .

The first light guide plate guide member 521 may further include an optical sheet receiving portion 521 G.

The optical sheet receiving portion 521 G may be recessed inwardly from the guide inclined surface 521 r . The optical sheet receiving portion 521 G may provide a space in which to receive a corner of each of the optical sheets 300 .

In exemplary embodiments, the optical sheet receiving portion 521 G is disposed substantially on the same plane as the top surface 100 a of the light guide plate 100 , or is disposed above the top surface 100 a of the light guide plate 100 . If the optical sheet receiving portion 521 G is disposed below the top surface 100 a of the light guide plate 100 , there may be difficulty in supporting the optical sheets 300 , which are disposed on the top surface 100 a of the light guide plate 100 , with the optical sheet receiving portion 521 G. Alternatively, disposing the optical sheet receiving portion 521 G substantially on the same plane as the top surface 100 a of the light guide plate 100 , or above the top surface 100 a of the light guide plate 100 , as is the case according to exemplary embodiments of the present inventive concept, results in the optical sheet receiving portion 521 G adequately supporting the optical sheets 300 . Referring to FIG. 7 , in an exemplary embodiment, the optical sheet receiving portion 521 G is disposed above the top surface 100 a of the light guide plate 100 , in which case, a predetermined gap is formed between the light guide plate 100 and the optical sheets 300 . When the optical sheet receiving portion 521 G is disposed on the same plane as the top surface of the light guide plate 100 , the optical sheets 300 may be placed in contact with the top surface 100 a of the light guide plate 100 .

Referring to FIG. 6 , in an exemplary embodiment, similar to the first light guide plate guide member 521 , the third light guide plate guide member 523 includes coupling portions 523 C, which are fixed to the body portion 510 of the housing 500 , and a guide inclined surface 523 r , which prevents the movement of the light guide plate 100 . Since the third light guide plate guide member 523 is disposed adjacent to the light source unit 200 , the shape of the third light guide plate guide member 523 may differ from the shape of the first light guide plate guide member 521 .

For example, the coupling portions 523 C of the third light guide plate guide member 523 differ from the coupling portions 521 C of the first light guide plate 521 in that they protrude inwardly beyond the third and fourth sidewalls 510 S 3 and 510 S 4 . For example, one of the coupling portions 523 C of the third light guide plate guide member 523 may be formed in consideration of the thickness of the light source unit 200 , which is disposed near the third sidewall 510 S 3 , to protrude inwardly beyond the third sidewall 510 S 3 . The light source unit 200 may emit heat in the process of generating light, and due to the generated heat, the light guide plate 100 may deteriorate. Thus, the light guide plate 100 may be spaced apart from the light source unit 200 , thereby preventing damage to the light guide plate 100 .

In an exemplary embodiment, the shape of the inclined surface 523 r of the third light guide plate guide member 523 corresponds to the shape of a corner inclined surface 100 r of the light guide plate 100 corresponding to the third light guide plate guide member 523 , and is disposed to intersect the light guide plate 100 in the lengthwise and widthwise directions of the light guide plate 100 . Accordingly, the third light guide plate guide member 523 , like the first light guide plate guide member 521 , prevents the movement of the light guide plate 100 in both the lengthwise and widthwise directions of the light guide plate 100 .

The inclined surfaces 521 r through 524 r of the first through fourth light guide plate guide members 521 through 524 prevents the movement of the light guide plate 100 in both the lengthwise and widthwise directions of the light guide plate 100 , and as a result, the light guide plate 100 is stably fixed inside the housing 500 .

Also, since the first through fourth light guide plate guide members 521 through 524 are disposed in the gaps provided at the corners 500 r of the housing 500 , the light guide plate 100 is stably fixed without increasing the bezel area of the display device 1 .

Backlight units according to exemplary embodiments of the present inventive concept will hereinafter be described, with the description primarily focusing on differences between the backlight units described hereinafter and the backlight unit 20 according to the exemplary embodiment of FIG. 2 . For convenience of explanation, a further description of elements and features that have already been described above may be omitted. FIGS. 8 through 13 illustrate the shapes of backlight units based on the mode of use of a display device. It is to be understood that if the mode of use of the display device changes, the shapes of the backlight units according to the exemplary embodiments of FIGS. 8 through 13 may also change in various manners.

FIGS. 8 and 9 are plan views of backlight units according to exemplary embodiments of the present inventive concept.

FIG. 8 shows that the inclination angle of inclined surfaces 520 r _ 2 of light guide plate is guide members 520 _ 2 of a display device 2 may change. For example, the inclination angle of the inclined surfaces 520 r _ 2 of the light guide plate guide members 520 _ 2 may change depending on the mode of use of the display device 2 .

Inclined surfaces 520 r _ 2 of light guide plate guide members 520 _ 2 that receive a relatively large load from the light guide plate 100 may have a larger inclination angle than inclined surfaces 520 r _ 2 of light guide plate guide members 520 _ 2 that receive a relatively small load from the light guide plate 100 .

For example, if a light source unit 200 of the display device 2 is disposed at a lower part of the display device 2 (e.g., with respect to the direction in which gravity acts), the load of the light guide plate 100 may be applied more considerably to second and third light guide plate guide members 522 _ 2 and 523 _ 2 than to first and fourth light guide plate guide members 521 _ 2 and 524 _ 2 . In this case, a first inclination angle α 1 of an inclined surface 522 r _ 2 of the second light guide plate guide member 522 _ 2 with respect to a second sidewall 510 S 2 _ 2 is smaller than a second inclination angle α 2 of an inclined surface 521 r _ 2 of the first light guide plate guide member 521 _ 2 with respect to the second sidewall 510 S 2 _ 2 . Also, the inclination angle of an inclined surface 523 r _ 2 of the third light guide plate guide member 523 _ 2 with respect to a fourth sidewall 510 S 4 _ 2 (e.g., the first inclination angle α 1 ) is smaller than the inclination angle of an inclined surface 524 r _ 2 of the fourth light guide plate guide member 524 _ 2 with respect to the fourth sidewall 510 S 4 _ 2 (e.g., the second inclination angle α 2 ).

For example, the second inclination angle α 2 may be about 45°, and the first inclination angle α 1 may be about 30°. When the load of the light guide plate 100 is m and gravitational acceleration is a, the load of the light guide plate 100 applied to the inclined surfaces 520 r _ 2 of the light guide plate guide members 520 _ 2 is about 0.36*ma when the inclined surfaces 520 r _ 2 of the light guide plate guide members 520 _ 2 have an inclination angle of about 45°, and may be reduced to about 0.25*ma when the inclined surfaces 520 r _ 2 of the light guide plate guide is members 520 _ 2 have an inclination angle of about 30°. For example, the steeper the slope of the inclined surfaces 520 r _ 2 , the less the load applied to the inclined surfaces 520 r _ 2 becomes. Thus, the inclination angle of the inclined surfaces 522 r _ 2 and 523 r _ 2 of the second and third light guide plate guide members 522 _ 2 and 523 _ 2 (e.g., the first inclination angle α 1 ) is smaller than the inclination angle of the inclined surfaces 521 r _ 2 and 524 r _ 2 of the first and fourth light guide plate guide members 521 _ 2 and 524 _ 2 (e.g., the second inclination angle α 2 ).

In FIG. 8 , a light guide plate 100 _ 2 corresponds to the light guide plate 100 previously described, and first and third sidewalls 510 S 1 _ 2 and 510 S 3 _ 2 correspond to the first and third sidewalls 510 S 1 and 510 S 3 previously described.

FIG. 9 shows that the inclination angle of inclined surfaces 520 r _ 3 of light guide plate guide members 520 _ 3 of a display device 3 may change.

The display device 3 of FIG. 9 differs from the display device 2 of FIG. 8 in that the display device 3 is positioned on its short side, whereas the display device 2 is positioned on its long side.

Referring to FIG. 9 , in an exemplary embodiment, the slope of inclined surfaces 521 r _ 3 and 522 r _ 3 of first and second light guide plate guide members 521 _ 3 and 522 _ 3 is greater than the slope of inclined surfaces 523 r _ 3 and 524 r _ 3 of third and fourth light guide plate guide members 523 _ 3 and 524 _ 3 . For example, a first inclination angle β 1 of the inclined surfaces 521 r _ 3 and 522 r _ 3 of the first and second light guide plate guide members 521 _ 3 and 522 _ 3 with respect to a second sidewall 510 S 2 _ 3 is smaller than a second inclination angle β 2 of the inclined surfaces 523 r _ 3 and 524 r _ 3 of the third and fourth light guide plate guide members 523 _ 3 and 524 _ 3 with respect to a fourth sidewall 510 S 2 _ 3 , which is substantially parallel to the second sidewall 510 S 2 _ 3 . As described above, the steeper the slope of the inclined surfaces of light guide plate guide members, the less the load applied to the inclined surfaces of the light guide plate guide members becomes. Thus, the inclined surfaces 521 r _ 3 and 522 r _ 3 of the first and second light guide plate guide members 521 _ 3 and 522 _ 3 , to which a relatively small load is applied, have a steeper slope than the inclined surfaces 523 r _ 3 and 524 r _ 3 of the third and fourth light guide plate guide members 523 _ 3 and 524 _ 3 .

In FIG. 9 , a light guide plate 100 _ 3 corresponds to the light guide plate 100 previously described, and first and third sidewalls 510 S 1 _ 3 and 510 S 3 _ 3 correspond to the first and third sidewalls 510 S 1 and 510 S 3 previously described.

FIG. 10 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 10 shows that in an exemplary embodiment, coupling members 530 of light guide plate guide members 520 of a display device 4 are coupled to the body portion 510 of the housing 500 .

Unlike the light guide plate guide members 520 of FIG. 1 , the light guide plate guide members 520 of FIG. 10 may be formed first and may be coupled later to the housing 500 .

The material of the light guide plate guide members 520 is not limited to a mold material, and the light guide plate guide members 520 may include various materials. For example, the light guide plate guide members 520 may include a material with elasticity such as silicone or rubber. In this case, the light guide plate guide members 520 may absorb impact that may be caused by the movement of a light guide plate 100 _ 4 . Thus, the light guide plate 100 _ 4 is further stably fixed, and the durability of the display device 4 is improved.

In FIG. 10 , a first light guide plate guide member 521 _ 4 corresponds to the first light guide plate guide member 521 previously described, a house coupling member 30 _ 4 corresponds to the house coupling member 30 previously described, a second sidewall 510 S 2 _ 4 corresponds to the second sidewall 510 S 2 previously described, and a third sidewall 510 S 3 _ 4 corresponds to the third sidewall 510 S 3 previously described.

FIG. 11 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept.

FIG. 11 shows that in an exemplary embodiment, an adhesive member 600 is disposed between the light guide plate guide members 520 of a light guide plate 100 _ 5 of a display device 5 .

The adhesive member 600 may include a material that can absorb impact. For example, the adhesive member 600 may be a polymer resin or an adhesive tape. In exemplary embodiments, the adhesive member 600 may include a light-absorbing material such as a black pigment or dye, or a reflective material, and may thus perform a light-blocking function that prevents light from leaking to unintended places, as described above.

The adhesive member 600 reduces or minimizes the movement of the light guide plate 100 _ 5 and absorbs impact, and thus, further stably fixes the light guide plate 100 _ 5 . Accordingly, the durability of the display device 5 is improved.

In FIG. 11 , the light guide plate 100 _ 5 corresponds to the light guide plate 100 previously described, a house coupling member 30 _ 5 corresponds to the house coupling member 30 previously described, a first sidewall 510 S 1 _ 5 corresponds to the first sidewall 510 S 1 previously described, a second sidewall 510 S 2 _ 5 corresponds to the second sidewall 510 S 2 previously described, and a first light guide plate guide member 521 _ 5 corresponds to the first light guide plate guide member 521 previously described.

FIG. 12 is a partial perspective view of a backlight unit according to an exemplary embodiment of the present inventive concept. FIG. 13 is a cross-sectional view taken along line XIII-XIII′ of FIG. 12 according to an exemplary embodiment of the present inventive concept.

Referring to FIGS. 12 and 13 , in an exemplary embodiment, the light guide plate guide member 520 of a display device 6 includes a protruding portion 521 P_ 6 .

In an exemplary embodiment, the protruding portion 521 P_ 6 is disposed on the inner sides of the side surfaces 100 s of a light guide plate 100 _ 6 . For example, in an exemplary embodiment, the protruding portion 521 P_ 6 partially covers the top surface 100 a of the light guide plate 100 _ 6 . The protruding portion 521 P_ 6 prevents the movement of the light guide plate 100 _ 6 in the height direction of the light guide plate 100 _ 6 .

The light guide plate guide member 520 , which includes the protruding portion 521 P_ 6 , prevents the movement of the light guide plate 100 _ 6 not only in the lengthwise and widthwise directions of the light guide plate 100 _ 6 , but also in the height direction of the light guide plate 100 _ 6 , and thus, further stably fixes the light guide plate 100 _ 6 .

In FIGS. 12 and 13 , a light guide plate 100 _ 6 corresponds to the light guide plate 100 previously described, a house coupling member 30 _ 6 corresponds to the house coupling member 30 previously described, a first sidewall 510 S 1 _ 6 corresponds to the first sidewall 510 S 1 previously described, a second sidewall 510 S 2 _ 6 corresponds to the second sidewall 510 S 2 previously described, optical sheets 300 _ 6 correspond to the optical sheets 300 previously described, a light guide plate guide member 521 _ 6 corresponds to the light guide plate guide member 521 previously described, and a bottom surface 510 B_ 6 corresponds to the bottom surface 510 previously described.

While the present inventive concept has been particularly shown and described with reference to the exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present inventive concept as defined by the following claims.