KR20110022915A - Backlight unit and display apparatus thereof - Google Patents

Abstract

PURPOSE: A backlight unit of a display apparatus is provided to improve a display quality by reducing light interference between adjacent blocks. CONSTITUTION: A backlight unit of a display apparatus comprises a plurality of light sources for projecting light to a first direction and a light guide plate(15) for projecting light to an upper direction. The backlight unit is composed of a plurality of blocks(B1~B5). The light sources are turn on and off by the block unit and has the same brightness. The light guide plate is overlapped with other adjacent light guide plate.

Description

Backlight unit and display apparatus using the same

The present invention relates to a backlight unit and a display device including the same.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescents (VFDs) have been developed. Various display devices such as displays have been studied and used.

Among them, the liquid crystal panel of the LCD includes a liquid crystal layer and a TFT substrate and a color filter substrate facing each other with the liquid crystal layer interposed therebetween, and have no self-luminous power to display an image using light provided from the backlight unit. can do.

An object of the present invention is to provide a backlight unit and a display device using the same that can improve the image quality of the display image.

According to an embodiment of the present invention, a backlight unit includes: light sources emitting light in a first direction; And a light guide plate for emitting side incident light from the light sources to the upper side, wherein the backlight unit is driven to be divided into a plurality of blocks, and the size of the divided blocks satisfies the following equation.

In the above equation, y is the first direction length of the block, x is the direction length perpendicular to the first direction of the block, Lx is the direction length perpendicular to the first direction of the light guide plate, and θ ' Is the directivity angle of the light in the light guide plate.

On the other hand, the display device according to an embodiment of the present invention comprises the backlight unit, a plurality of areas of the display panel and a plurality of blocks of the backlight unit correspond to each other, from each of the blocks of the backlight unit The luminance of the provided light is adjusted according to the gray level peak value or the color coordinate signal of the corresponding display panel region.

According to an exemplary embodiment of the present invention, when the backlight unit is divided into a plurality of blocks, optical interference between adjacent blocks may be reduced, such as local dimming or impulsive. When the partial driving method is used, the image quality of the display image may be improved.

Hereinafter, with reference to the accompanying drawings as follows. Hereinafter, the embodiments may be modified in various forms, and the technical scope of the embodiments is not limited to the embodiments described below. The examples are provided to more fully illustrate those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity.

1 is an exploded perspective view showing the overall configuration of a display device.

Referring to FIG. 1, the display apparatus 1 includes a display module 200, a front cover 300 and a back cover 400 surrounding the display module 200, and a display cover 200 with the front cover 300. And / or a fixing member 500 for fixing to the back cover 400.

One side of the fixing member 500 is fixed to the front cover 300 by a fastening member such as a screw, etc., and the other side supports the display module 200 with respect to the front cover 300 to display the front cover 300. Module 200 may be fixed.

In this embodiment, the fixing member 500 is described as being formed in a plate shape extending in one direction as an example, but the separate fixing member 500 is not provided, and the display module 200 is provided by the fastening member. It is also possible that the configuration fixed to the front cover 300 or the back cover 400 is possible.

2 is a cross-sectional view of an embodiment of a display module configuration, and illustrates a cross-sectional configuration of the display module 200 cut along the line A-A of FIG. 1.

Referring to FIG. 2, the display module 200 may form a display panel 210 on which an image is displayed, a backlight unit 100 that provides light to the display panel 210, and a lower exterior of the display module 200. A bottom cover 110, a panel supporter 240 supporting the display panel 210 from below, and a top cover 230 supporting the display panel 210 from above and forming an edge of the display module 200. .

The bottom cover 110 may be formed in a box shape having an upper surface open to accommodate the backlight unit 100.

One side of the bottom cover 110 may be fixed to one side of the top cover 230. For example, a fastening member such as a screw penetrates the side surface of the display module 200, that is, the side where the bottom cover 110 and the top cover 230 overlap each other, and thus the bottom cover 110 and the top cover 230 may be separated. Can be fixed

Although not shown in detail, the display panel 210 includes, for example, a lower substrate 211 and an upper substrate 222 and a liquid crystal layer interposed between the two substrates so as to maintain a uniform cell gap facing each other. can do. A plurality of gate lines and a plurality of data lines intersecting the plurality of gate lines may be formed on the lower substrate 211, and a thin film transistor (TFT) may be formed at an intersection of the gate lines and the data lines. have.

Meanwhile, color filters may be formed on the upper substrate 212, but the structure of the display panel 210 is not limited thereto, and the display panel 210 may have various structures. For example, the lower substrate 211 may include not only a thin film transistor but also a color filter. In addition, the display panel 210 may be formed in various shapes according to a method of driving the liquid crystal layer.

In addition, a gate driving printed circuit board (PCB) for supplying a scan signal to a gate line and a data driving printed circuit board (PCB) for supplying a data signal to a data line are provided at an edge of the display panel 210. ) May be provided. A polarizing film (not shown) may be disposed on at least one of the top and bottom of the display panel 210.

An optical sheet 220 may be disposed between the display panel 210 and the backlight unit 100, and the optical sheet 220 may be removed, but is not limited thereto. The optical sheet 220 may include a diffusion sheet (not shown) or a prism sheet (not shown).

The diffusion sheet evenly spreads the light emitted from the light guide plate, and the diffused light may be focused onto the display panel by the prism sheet. Here, the prism sheet may be selectively configured using a horizontal or / and vertical prism sheet, one or more roughness reinforcing films, and the like. The type or number of optical sheets 220 may be added or deleted within the technical scope of the embodiment, but is not limited thereto.

Meanwhile, the backlight unit 100 may include a plurality of optical assemblies 10 forming a plurality of split driving blocks. In addition, the display panel 210 has a plurality of divided regions corresponding to each of the optical assemblies 10, and the optical assemblies 10 may emit the luminance of the display panel 210 according to gray peak values or color coordinate signals of the divided regions. Can be adjusted.

In addition, the optical assembly 10 may include a light source 13 and a light guide plate 15, and the light source 13 is positioned at the side of the light guide plate 15, so that light emitted from the light source 13 may be light guide plate 15. May be incident on the side of

For example, the light source 13 may be configured using a light emitting diode (LED), and may include a plurality of light emitting diodes (LEDs). The light emitting diode may be a side light emitting type, and may be implemented as a colored LED or a white LED emitting at least one of colors such as red, blue, and green. In addition, the colored LED may include at least one of a red LED, a blue LED, and a green LED, and the arrangement and emission light of such a light emitting diode may be changed within the technical scope of the embodiment.

Meanwhile, the light guide plate 15 is made of a transparent material, and includes, for example, one of an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), and polyethylene naphthalate (PEN) resin. can do. The light guide plate 15 may be formed by an extrusion molding method.

The light guide plate 15 may be refracted and scattered from the light source 13 to emit light in an upper direction, that is, in a direction of the display panel 210. In addition, a reflective member (not shown) may be formed below the light guide plate 15.

Meanwhile, the shape or structure of the liquid crystal panel 210, the backlight unit 100, or the optical assembly 10 included in the backlight unit 100 illustrated in FIG. 2 is an embodiment according to the present invention, and the present invention is limited thereto. Not.

3 is a plan view showing an embodiment of the configuration of the backlight unit 100 and briefly illustrates a configuration of the backlight unit 100 viewed from the front.

Referring to FIG. 3, a plurality of optical assemblies 10 included in the backlight unit 100 may be arranged in a matrix form with N and M (N, M being one or more natural numbers) in the x and y axis directions, respectively. As described above, the optical assembly 10 may include a light source 13 and a light guide plate 15.

The backlight unit 100 according to an exemplary embodiment of the present invention may be driven by a split driving method such as local dimming or impulsive. The driving method of the backlight unit 100 may be variously changed according to a circuit design, but is not limited thereto. As a result, the color contrast ratio is increased and the image of the bright and dark portions on the screen can be clearly expressed, thereby improving image quality.

That is, the backlight unit 100 may be operated by being divided into a plurality of divided driving blocks, and the black portion of the image reduces the luminance and the bright portion the luminance by linking the luminance of the divided block with the luminance of the image signal. By increasing, the contrast ratio and the sharpness can be improved.

For example, when the backlight unit 100 is driven by a local dimming method, the display panel 210 has a plurality of divided regions corresponding to each of the divided blocks of the backlight unit 100, and the display panel 210. The luminance of each of the divided blocks of the backlight unit 100 may be adjusted according to the peak value or the color coordinate signal of the gray level of each of the divided regions.

Hereinafter, the configuration and driving method of the backlight unit 100 according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 3.

As shown in FIG. 3, the backlight unit 100 may be divided into a plurality of blocks B, and the plurality of blocks B may each include a plurality of light sources 13 and the light sources 13. It may include a light guide plate 15 for emitting a side incident light from the upper side.

Meanwhile, one optical assembly 10 may also be divided into a plurality of blocks, for example, three blocks in FIG. 3, whereby an area where one light guide plate 15 is disposed is divided into a plurality of blocks. It can be divided and driven.

The block B of the backlight unit 100 is a basic unit to which driving power for emitting light is supplied, that is, the light sources 13 included in one block B are simultaneously turned on or turned off. It is turned off and can emit light of the same brightness when turned on. In addition, light sources included in different blocks of the backlight unit 100 may be supplied with different driving powers to emit light having different luminance.

In the case shown in FIG. 3, the backlight unit 100 may include three optical assemblies 10 in the x-axis direction and eight (24 total) in the y-axis direction. ) May be divided into three blocks, and the driving may be divided into a total of 72 blocks.

The backlight unit 100 shown in FIG. 3 is only an embodiment of the present invention, and the present invention is not limited thereto. That is, the number of the optical assembly 10 included in the backlight unit 100 or the number of the blocks 10 driven separately may be changed.

4 illustrates a portion of the backlight unit 100, wherein light emitted from the light sources 13 is incident on the light guide plate 15 about one of the divided blocks B1 of the backlight unit 100. It is shown to proceed. Accordingly, in FIG. 4, detailed configurations of the remaining blocks B2 to B5 except for the B1 block are omitted.

Referring to FIG. 4, the B1 block of the plurality of blocks of the backlight unit 100 may include a partial region of the light guide plate 15 and the light sources 13 corresponding to the B1 block. In addition, as described above, the light sources 13 included in the B1 block may be turned on or off at the same time and may emit light having the same luminance.

The light sources 13 included in the B1 block emit light in the direction of the light guide plate 15, and the light emitted from the light sources 13 travels at a constant direction angle θ ′ in the light guide plate 15. Can be.

Accordingly, as shown in FIG. 4, light emitted from the light sources 13 included in the B1 block extends to adjacent blocks B2 and B3, and is emitted from the light sources 13 of the B1 block. The emitted light may generate light emitting regions in adjacent blocks B2 and B3.

The distance d of the light emitted from the light sources 13 of the B1 block may be calculated by Equation 1 below.

In Equation 1, y is a block length in a direction in which light is emitted from the light source 13, that is, in the y-axis direction, that is, y is a length in the y-axis direction of the light guide plate 15 as shown in FIG. Can be.

On the other hand, θ 'is a direction angle at which the light emitted from the light source 13 travels in the light guide plate 15.

As described above, it is difficult to prevent the light emitted from the light sources 13 included in the B1 block from reaching the adjacent blocks B2 and B3, but the light emitting area extends from one block to the adjacent blocks B4 and B5. In this case, a decrease in contrast of the display image due to interference between blocks may be significantly increased.

Therefore, according to the exemplary embodiment of the present invention, the light emitted from the light sources 13 included in the B1 block does not reach the adjacent blocks B4 and B5 by one block, thereby minimizing the influence between the adjacent blocks. Therefore, the image quality of the display image can be improved accordingly.

In order to prevent the light emitted from the light sources 13 included in the B1 block from reaching the B4 or B5 block as described above, the following Equation 2 must be satisfied.

In Equation 2, x is a block length in a direction perpendicular to the direction in which light is emitted from the light source 13, that is, in the x-axis direction.

For example, as shown in FIG. 4, x is the distance between the right end of the rightmost light source 13a of the B3 block left adjacent to the B1 block and the right end of the rightmost light source 13b of the B1 block. Can be.

That is, as shown in Equation 2, when the distance d of the light emitted from the light sources 13 included in the B1 block is equal to or less than the length x of the block B in the x-axis direction, the light source included in the B1 block Light emitted from the fields 13 may not reach the B4 or B5 block.

Meanwhile, since one optical assembly 10 includes one or more blocks B, the x-axis length x of the block B may be less than or equal to the x-axis length Lx of the light guide plate 15. The y-axis length y of (B) may be the same as the y-axis length Ly of the light guide plate 15.

Accordingly, when the x-axis length x of the block B satisfies the following Equation 3, the image quality of the display image may be improved by minimizing the influence between adjacent blocks of the backlight unit 100.

FIG. 5 illustrates an angle at which light emitted from the light source 13 is refracted by the light guide plate 15.

Referring to FIG. 5, as the refractive index n1 of the portion where light is emitted from the light source 13 and the refractive index n2 of the light guide plate 15 are different from each other, the direction angle θ of the light emitted from the light source 13 and After the emitted light is incident on the light guide plate 15, the direction angle θ ′ of the light in the light guide plate 15 may be different.

The light directivity angle θ from the light source 13 and the light directivity angle θ ′ in the light guide plate 15 may have a relationship as shown in Equation 4 according to Snell's law.

On the other hand, considering that the portion where the light is emitted from the light source 13 is the air layer (refractive index n1 is '1'), and in general, the direction angle θ of the light emitted from the light source 13 is 60 degrees, According to Equation 4, the light directing angle θ 'in the light guide plate 15 may have the same value as in Equation 4 below.

In addition, when the light guide plate 15 is formed of an acrylic resin series such as polymethyl metaacrylate (PMMA), since the refractive index of the light guide plate 15 may be about 1.5, the light directing angle in the light guide plate 15 according to Equation 5 (θ ') may be about 35.5 degrees.

Substituting 35.5 degrees, which is the calculated light directing angle θ 'in the light guide plate 15 into Equation 3, the y-axis length y of the block B is equal to the x-axis length x of 1.4 times or less.

That is, when the y-axis length y of the block B is 1.4 times or less the x-axis length x, the image quality of the display image may be improved by minimizing the influence between adjacent blocks of the backlight unit 100. have.

FIG. 6 is a diagram illustrating the directivity angle of light, and the directivity angle θ of light may be defined as shown in FIG. 6. That is, the directivity angle θ of the light is an angle at which one half of the luminous intensity of the brightest part is obtained, and the angle at which one half of the luminous intensity is obtained may be represented by 2θ.

7 illustrates a cross-sectional configuration of a backlight unit according to an embodiment of the present invention.

Referring to FIG. 7, the optical assembly 10 includes a light source 13, a light guide plate 15, a reflective member 17, and a side cover 20 for fixing the light source 13 and the light guide plate 15. Can be. Meanwhile, the side cover 20 provides a fixed position with respect to the bottom cover 110 and may include a first side cover 21 and a second side cover 22.

The light guide plate 15 may be composed of a first part 15b and a second part 15a, and the second part 15a may be formed of four sides of an upper surface of the surface light source and a lower surface of the upper surface of the light source. Can be.

In addition, the first part 15b may be formed to protrude in a horizontal direction along a lower side of one of the side surfaces of the second part 15a. Here, the first part 15b is a light incident part through which light is incident from the light source 13, and the second part 15a substantially emits light incident on the side through the light incident part to the upper side to substantially display the display panel 210. It may be a light emitting unit for providing light to.

According to an embodiment of the present invention, the optical assemblies 10 adjacent to each other, more specifically, two light guide plates 15 adjacent to each other, may be disposed so that predetermined regions overlap each other.

For example, the light source 13, the first part 15b, that is, the light incident part and the side cover 20, are disposed on one side of the optical assembly 10, and the light source 13 and the first light source of the optical assembly 10 are disposed. The first part 15b and the side cover 20 are disposed adjacent to the optical assembly 10 disposed adjacently, more specifically, to the second part 15a of the light guide plate 15 provided in the optical assembly, that is, under the light emitting unit. Can be.

As the plurality of optical assemblies 10 are partially overlapped as described above, the light source 13, the first part 15b and the side cover 20 may not be observed from the front surface.

As described above, as the adjacent optical assemblies 10 included in the backlight unit 100 overlap each other, the bright or dark lines may be improved at the boundary of the optical assemblies 10 and the uniformity of light may be secured. .

On the other hand, a scattering pattern (not shown) may be formed on an upper surface or a lower surface of the light guide plate 15, and the scattering pattern may be formed in a predetermined pattern to diffuse light incident on the light guide plate 15 to improve light uniformity. Play a role.

On the other hand, the second part 15a of the light guide plate 15, that is, the lower surface of the light emitting part is formed to be inclined at a predetermined angle, and the thickness may gradually become thinner toward the opposite side from the portion adjacent to the first part 15b.

A reflective member 17 may be provided on a lower surface of the light guide plate 15, and the reflective member 17 may be guided in the light guide plate 15 by light incident to the side of the light guide plate 15 through the first part 15b. ), And then it can be emitted upward. In addition, the reflective member 17 may serve to block interference by light generated from another optical assembly 10 disposed in an overlapping manner.

FIG. 8 is a perspective view illustrating an embodiment of a shape of the light guide plate 15 included in the backlight unit 100.

7 and 8, the light guide plate 15, more specifically, the first part 15b of the light guide plate 15 may include a protrusion 30 protruding at a predetermined height a. On the other hand, the projections 30 may be formed in at least two places in the x-axis direction on the upper surface of the first part 15b of the light guide plate 15.

The protrusion 30 may have various shapes, for example, may have a shape similar to a cuboid. The protrusion 30 can be prevented from shaking of the light guide plate 15 along the x-axis and the y-axis by engaging the first side cover 21.

Some of the corners 30a of the protrusions 30 may be rounded to prevent cracks in the protrusions due to the impact applied to the protrusions 30 by the movement of the light guide plate 15.

On the other hand, the projection 30 may have a height (a) of 0.3 ~ 0.6mm from the upper surface of the first part (15b). Width b on the x-axis of the projection 30 may be 2 ~ 5mm. Width c in the y-axis of the projection 30 may be 1 ~ 3mm.

The protrusion 30 may be disposed between adjacent light emitting diodes 11, and the light generated in the light emitting diodes 11 may be formed near the light incident surface 16 on the upper surface of the first part 15b. Due to the projections 30 formed integrally with the light guide plate 15, it is possible to prevent optical interference from occurring.

Meanwhile, the light source 13 may include at least one light emitting diode 11 and a module substrate 12 on which the light emitting diode 11 is mounted. The light emitting diodes 11 may be arranged on the module substrate 12 in the x-axis direction and disposed to be adjacent to the light incident surface 16 of the first part 15b.

The module substrate 12 is made of a metal core PCB, FR-4 PCB, a general PCB, a flexible substrate, etc., can be variously changed within the technical scope of the embodiment. In addition, a heat dissipation member (thermal pad, not shown) may be disposed under the module substrate 12. The heat dissipation member may be formed between the module substrate 12 and the second side cover 22.

The light generated by the light emitting diodes 11 is incident sideways to the first part 15b. Light incident from the light emitting diodes 11 may be mixed in the light guide plate 15 including the first part 15b.

 Light incident from the light emitting diodes 11 is guided in the first part 15b and is incident to the second part 15a. The light incident on the second part 15a is reflected by the reflecting member 17 on the lower surface and emitted to the upper surface. In this case, since light is scattered and diffused by the scattering pattern formed on the lower surface of the light guide plate 15, light uniformity may be improved.

The light emitting diodes 11 may be disposed on the module substrate 12 at predetermined intervals. The light emitting diode 11 may be disposed in an oblique direction with respect to the protrusion 30 in order to minimize the optical effect of the protrusion 30 formed on the light guide plate 15. Thus, the spacing of the light emitting diodes 11 around the protrusion 30 may be wider than the spacing of other light emitting diodes 11.

The light emitting diodes 11 may be provided to secure a space for coupling the first side cover 21 and the second side cover 22 and to minimize an optical effect that may be generated by the light guide plate 15 being pressed by the coupling force. The spacing of some of the light emitting diodes 11 may be wider than the spacing of other light emitting diodes 11.

For example, if the first spacing d of the adjacent light emitting diodes 11 is about 10 mm, the second spacing e of the light emitting diodes 11 near the position where a space for coupling is provided may be about 13 mm. .

Light generated by the light emitting diodes 11 may be mixed in the light guide plate 15 including the first part 15b and uniformly provided to the second part 15a.

Meanwhile, the side cover 20 is formed to surround a portion of the light source 13 and the light guide plate 15, and the side cover 20 is disposed above the first part 15b of the light source 13 and the light guide plate 15. The first side cover 21 and the second side cover 22 disposed below the first part 15b may be included. The side cover 20 may be made of plastic or metal.

The second side cover 22 is formed to face the lower surface of the first part 15b. The second side cover 22 may be bent in an upward direction (z-axis line) to face the light incident surface 16 on the lower surface of the first part 15b. A part 22a of the second side cover 22 may be formed to be inclined along the lower surface of the light guide plate 15, that is, the inclined surface, and the light source 13 may be accommodated in the second side cover 22.

The first side cover 21 and the second side cover 22 are fastened to each other by the first fixing member 51 so that the light source 13 and the light guide plate 15 are not shaken by an external impact, in particular in the z-axis direction. Make sure that shaking is prevented.

The second side cover 22 may support the inclined surface of the light guide plate 15 to maintain the alignment of the light guide plate 15 and the light source 13 firmly and to protect from external impact.

The first side cover 21 may have a first hole 41 formed at a position corresponding to the protrusion 30 of the first part 15b.

The first hole 41 may be formed larger than the protrusion 30 so that the protrusion 30 is fitted. The circumference of the first hole 41 may be spaced apart from a predetermined edge of the fitted protrusion 30 by a predetermined distance, which is spaced apart from the light guide plate 15 when the light guide plate 15 is expanded by an external environment change, for example, a sudden temperature rise. It may be a margin for preventing deformation of 15. In this case, another portion of the protrusion 30 may contact the circumference of the first hole to strengthen the fixing force.

At least one second hole 42 may be further formed in the first side cover 21. At least one third hole 43 may be formed in the second side cover 21 at a position corresponding to the second hole 42.

The backlight unit 100 having the configuration as described above may be accommodated in a box-shaped bottom cover having an upper side opened.

The present invention has been described above with reference to preferred embodiments thereof, which are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component shown in detail in the embodiment of the present invention may 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 an exploded perspective view showing the configuration of a display device.

2 is a cross-sectional view illustrating an embodiment of a configuration of a display module.

3 is a plan view briefly illustrating a configuration of a backlight unit according to an exemplary embodiment of the present invention.

FIG. 4 is a view illustrating a part of the backlight unit shown in FIG. 3.

5 is a view illustrating an angle at which light emitted from a light source is refracted in the light guide plate.

6 is a view for explaining a direction of light.

7 is a cross-sectional view illustrating a cross-sectional structure of a backlight unit according to an exemplary embodiment of the present invention.

FIG. 8 is a perspective view illustrating an embodiment of a shape of the light guide plate illustrated in FIG. 11.

Claims (10)

Light sources emitting light in a first direction; And a light guide plate emitting upwardly side incident light from the light sources. The backlight unit is divided and driven into a plurality of blocks, The size of the divided block is a backlight unit that satisfies the following equation.

In the above equation, y is the first direction length of the block, x is the direction length perpendicular to the first direction of the block, Lx is the direction length perpendicular to the first direction of the light guide plate, and θ ' Is the directivity angle of the light in the light guide plate. The method of claim 1, wherein y is And a backlight unit that is a length of the light guide plate in the first direction. The method of claim 1, And the light sources belonging to any one of the plurality of blocks are turned on and off at the same time. The method of claim 3, And a light source belonging to the one block emits light of the same brightness. The method of claim 1, And a first direction length (y) of the block is 1.4 times or less of a direction length (x) perpendicular to the first direction. The method of claim 1, It is provided with a plurality of light guide plates, At least a portion of the plurality of light guide plates adjacent to each other of the plurality of light guide plates overlap each other. The method of claim 6, wherein the light guide plate A light incident part to which the light is incident on the side and a light emitting part to emit the incident light upward; And a light incident part of the first light guide plate of the two adjacent light guide plates overlapping at least a part of the light emitting parts of the second light guide plate. The method of claim 7, wherein the light guide plate The backlight unit is reduced in thickness from one side where the light incident portion is located toward the other end. The method of claim 1, And a side cover to which the light sources and the light guide plate are fixed. A backlight unit according to any one of claims 1 to 9; And A display panel configured to receive light from the backlight unit and display an image; A plurality of areas of the display panel and a plurality of blocks of the backlight unit correspond to each other, so that the luminance of light provided from each of the blocks of the backlight unit corresponds to a gray level peak value or a color coordinate signal of the corresponding display panel area. Display device adjusted accordingly.

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