KR102486326B1 - Backlight unit and display device comprising the same - Google Patents

Abstract

An embodiment of the present invention includes a base substrate, a plurality of light sources disposed on the base substrate, and a barrier rib disposed on the base substrate to define a light emitting cell, wherein the light emitting cell includes at least one light source. And, the light source provides a side light type, backlight unit that emits light parallel to the surface of the base substrate.

Description

Backlight unit and display device including the same {BACKLIGHT UNIT AND DISPLAY DEVICE COMPRISING THE SAME}

The present invention relates to a backlight unit and a display device including the same, and more particularly, to a backlight unit capable of realizing local dimming and a display device including the same.

With the recent development of information and communication technologies, demand for a display device that visually displays electrical information signals is increasing. In particular, demand for thinning, lightening, and low power consumption of various flat display devices is increasing.

Representative examples of the flat panel display include a liquid crystal display device (LCD), a field emission display device (FED), and an organic light emitting display device (OLED). Among them, a liquid crystal display (LCD) has excellent image quality, light weight, thin shape, and low power consumption and is used in various fields.

A liquid crystal display device (LCD) consists of a liquid crystal panel that displays an image using liquid crystal having anisotropy such as refractive index and permittivity, a driving circuit that drives the liquid crystal panel, and a backlight unit that radiates light to the liquid crystal panel. include

In general, a backlight unit may be classified into a direct type and an edge type according to an arrangement method of light sources. The direct backlight unit includes a plurality of light sources disposed below the liquid crystal display panel and directly irradiates light to the entire surface of the liquid crystal display panel. The side light type backlight unit guides light generated from a light source disposed on a side surface to a light guide plate and irradiates the liquid crystal display panel with light.

Recently, in order to improve the contrast ratio (CR) of an image and minimize power consumption, a light source is divided into a plurality of light emitting blocks, and the amount of light of the light emitting blocks is controlled in response to the luminance of the image corresponding to the light emitting blocks. A local dimming drive method has been developed. Since the local dimming method divides the backlight unit into a plurality of light emitting blocks and controls the amount of light for each light emitting block, the contrast ratio of the display screen can be improved and power consumption can be reduced.

1. Korean Patent Publication No. 10-2017-0061535 2. Korean Patent Publication No. 10-2010-0101735

One embodiment of the present invention is to provide a backlight unit that can be driven in a local dimming method while having a thin thickness by arranging sidelight type light sources in light emitting cells divided by barrier ribs.

Another embodiment of the present invention is to provide a display device including such a backlight unit.

An embodiment of the present invention for achieving the above technical problem includes a base substrate, a plurality of light sources disposed on the base substrate, and a barrier rib disposed on the base substrate to define a light emitting cell, wherein the light emitting cell includes at least one light source, and the light source is a side light type that emits light parallel to the surface of the base substrate.

The barrier rib surrounds the light source on a plane.

The barrier rib has light reflectivity.

The barrier rib has a height of 0.3 to 1.0 mm.

The backlight unit further includes a reflective layer disposed on the base substrate.

The backlight unit further includes at least one reflective pattern disposed on the base substrate.

The backlight unit further includes a polymer resin filled between the barrier ribs.

The polymer resin has a refractive index of 1.5 or more.

The backlight unit further includes an optical sheet disposed on the barrier rib.

The backlight unit further includes a printed circuit board (PCB) disposed on the base substrate, and the light source is connected to the printed circuit board (PCB).

The plurality of light sources are grouped into a plurality of light emitting blocks, and each of the plurality of light emitting blocks includes at least one light source.

Each of the plurality of light emitting blocks is independently turned on or off.

Another embodiment of the present invention includes a backlight unit and a display panel disposed on the backlight unit, wherein the display panel includes a first substrate, a second substrate disposed opposite to the first substrate, and the first substrate. A liquid crystal layer disposed between a substrate and the second substrate, wherein the backlight unit includes a base substrate, a plurality of light sources disposed on the base substrate, and barrier ribs disposed on the base substrate to define light emitting cells; , The light emitting cell includes at least one light source, and the light source emits light parallel to the surface of the base substrate.

According to an embodiment of the present invention, the side light type light sources are arranged in light emitting cells separated by a lattice, so that the backlight unit can selectively emit light while having a small thickness. In addition, the backlight unit according to an embodiment of the present invention includes sidelight type light sources divided into units of light emitting blocks, and can control light emission in units of light emitting blocks, so that it can be driven in a local dimming method.

A display device according to another embodiment of the present invention includes a backlight unit driven by a local dimming method, and can display a high dynamic range (HDR) image.

In addition to the effects mentioned above, other features and advantages of the present invention will be described below, or will be clearly understood by those skilled in the art from such description and description.

1 is a plan view of a backlight unit according to an exemplary embodiment of the present invention.
FIG. 2 is a perspective view of part “A” in FIG. 1 .
3 is a cross-sectional view taken along line II′ of FIG. 2 .
4 is a schematic plan view of a backlight unit according to another embodiment of the present invention.
5 is a partial plan view of a backlight unit according to still another embodiment of the present invention.
6 is a schematic cross-sectional view of a display device according to another exemplary embodiment of the present invention.
7 is a schematic cross-sectional view of a backlight unit according to a comparative example.
8A is an emission photograph of a backlight unit according to Comparative Example 1;
8B is an emission picture of the backlight unit according to the first embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

Since the shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, the present invention is not limited to those shown in the drawings. Like elements may be referred to by like reference numerals throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless the expression 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless the word 'directly' is used, one or more other parts may be located between the two parts. When an element is said to be disposed "on" another element, the element is not necessarily located on top of the other element in the drawing. Since the top and bottom of a target object may vary depending on how the object is arranged, the fact that a component is placed "on" another component means that a component is placed "on top" of another component in the drawings or in the actual configuration. This includes not only the case of being placed "on", but also the case where a component is placed "below" another component.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal precedence relationship is described in terms of 'after', 'following', 'next to', 'before', etc. Unless the expression is used, non-continuous cases may also be included.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned below may also be the second component within the technical spirit of the present invention.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, "at least one of the first item, the second item, and the third item" means two of the first item, the second item, and the third item as well as each of the first item, the second item, and the third item. It may mean a combination of all items that can be presented from one or more.

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship. may be

Hereinafter, a backlight unit and a display device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3.

1 is a plan view of a backlight unit 100 according to an embodiment of the present invention, FIG. 2 is a perspective view of part "A" in FIG. 1, and FIG. 3 is a cross-sectional view taken along line II' in FIG. .

The backlight unit 100 according to an embodiment of the present invention includes a base substrate 110, a plurality of light sources 120 disposed on the base substrate 110, and light emitting cells 101 disposed on the base substrate 110. ) and a partition wall 130 defining the The light emitting cell 101 defined by the barrier rib 130 includes at least one light source 120 .

The base substrate 110 supports other components of the backlight unit 100 . Specifically, the base substrate 110 serves to support the light source 120 and the barrier rib 130 . The type of base substrate 110 is not particularly limited. A substrate made of metal or plastic, a reflective plate, or a bottom cover made of a metal material may be the base substrate 110 .

A printed circuit board (PCB) 140 is disposed on the base substrate 110 . A printed circuit board (PCB) 140 is connected to the light source 120 to control light emission of the light source 120 . The plurality of light sources 120 connected to the printed circuit board (PCB) 140 may be independently turned on and off. The printed circuit board (PCB) 140 may be disposed on the entire surface of the base substrate 110 or may be disposed only on a portion of the base substrate 100 .

3, it is illustrated that the printed circuit board (PCB) 140 is disposed under the light source 120, but one embodiment of the present invention is not limited thereto. A printed circuit board (PCB) 140 may be disposed above the light source 120, and may be disposed on the side or rear side of the light source.

The reflective layer 150 is disposed on the base substrate 110 . More specifically, referring to FIG. 3 , the reflective layer 150 is disposed on a printed circuit board (PCB) 140 on the base substrate 110 . The reflective layer 150 may be formed of, for example, a reflective sheet. However, one embodiment of the present invention is not limited thereto, and the surface of the base substrate 110 may serve as the reflective layer 150 .

Specifically, when the printed circuit board (PCB) 140 is disposed on the upper, side, or rear surface of the light source 120 or disposed on the lower surface of the base substrate 110, the reflective layer 150 is omitted, and the base substrate ( 110) may serve as the reflective layer 150. At this time, reflection treatment may be performed on the surface of the base substrate 110 . When the base substrate 110 has light reflectivity, reflection treatment on the surface of the base substrate 110 may not be required.

The reflective layer 150 allows light generated from the light source 120 to travel upward to the light emitting cell 101 . For example, some of the light generated by the light source 120 may be reflected by the reflective layer 150 and travel upward to the light emitting cell 101 . Alternatively, some of the light generated by the light source 120 may be reflected from the barrier rib 130 and then reflected again from the reflective layer 150 to proceed to the top of the light emitting cell 101 . Accordingly, light may be irradiated to the display panel 190 disposed above the backlight unit 100 (see FIG. 6 ).

The backlight unit 100 according to an embodiment of the present invention has at least one reflective pattern 160 disposed on the base substrate 110 . Referring to FIG. 3 , the reflective pattern 160 may be disposed on the reflective layer 150 on the base substrate 110 . When the base substrate 110 has light reflectivity, the reflective pattern 160 may be formed on the surface of the base substrate 110 .

The reflective pattern 160 may have a protrusion protruding from the reflective layer 150 . The shape of the reflective pattern 160 is not particularly limited, and protrusions of various shapes may be used as the reflective pattern 160 . For example, the reflective pattern 160 may have a shape of a spherical protrusion, a hemispherical protrusion, a prism, a pyramid, a pyramid, or a bar. More specifically, the reflective pattern 160 may have a planar shape of any one of a circular shape, an elliptical shape, and a polygonal shape.

The reflective pattern 160 may change a path of light by reflecting light. As the path of light is changed by the reflective pattern 160 , the light generated from the light source 120 can travel upward. Light extraction efficiency of the backlight unit 100 may be improved by the reflective pattern 160 .

The light source 120 is disposed on the base substrate 110 . Referring to FIG. 3 , the light source 120 is disposed on the reflective layer 150 on the base substrate 110 .

According to one embodiment of the present invention, the light source 120 is a side emitting type that emits light parallel to the surface of the base substrate 110 . In FIG. 3 , when the x-axis direction is referred to as a side direction and the y-axis direction is referred to as a vertical direction, light generated from the light source 120 travels in the side direction. The light source 120 generating light traveling in a side direction is also referred to as a "side light type light source" or a "side light source".

The type of light source 120 is not particularly limited. As the light source 120, for example, a light emitting diode (LED) may be used. The light source 120 may emit white light. However, one embodiment of the present invention is not limited thereto, and the light source 120 may emit blue light. In this case, for example, a blue light emitting diode (blue LED) may be used.

The barrier rib 130 is disposed on the base substrate 110 . Referring to FIGS. 1 and 2 , the barrier rib 130 surrounds the light source 120 in plan view. The light emitting cell 101 is defined by the area surrounded by the barrier rib 130 . Referring to FIG. 3 , a 3D space of the light emitting cell 101 may be defined by the barrier rib 130 and the reflective layer 150 . At this time, the reflective layer 150 becomes the bottom surface of the light emitting cell 101 .

2 and 3 show that one light emitting cell 101 includes one light source 120 . However, one embodiment of the present invention is not limited thereto, and one light emitting cell 101 may include two or more light sources 120 .

The barrier rib 130 blocks light generated from the light source 120 disposed in the light emitting cell 101 from traveling to another light emitting cell 101 . In this way, the barrier rib 130 defines a light emitting area of the light source 120 . Since the light emitting area of the light source 120 is limited by the barrier rib 130, the light emitting area of the backlight unit 100 can be selectively controlled by controlling the on-off of the plurality of light sources 120. there is.

The barrier rib 130 has light reflectivity. According to an embodiment of the present invention, since the light source 120 is a side light type and is surrounded by the barrier rib 130 with respect to a plane, the light generated from the light source 120 is emitted from the barrier rib 130. can be reflected from The light reflected from the barrier rib 130 may travel upward according to the reflection angle, may be reflected again from another barrier rib 130, or may be reflected by the reflective pattern 160 to travel upward. Accordingly, light generated from the light source 120 may travel to an upper portion of the region surrounded by the barrier rib 130 .

The height of the barrier rib 130 may be determined by the height of the light source 120 . According to one embodiment of the present invention, the barrier rib 130 may have a height of 0.3 to 1.0 mm. More specifically, the barrier rib may have a height of 0.3 to 0.7 mm. The height of the barrier rib 130 corresponds to the distance between the reflective layer 150 and the optical sheet 180. Since the distance between the reflective layer 150 and the optical sheet 180 is short, the backlight unit according to an embodiment of the present invention (100) may have a thin thickness.

More specifically, referring to FIG. 3 , the height of the barrier rib defines a distance between the reflective layer 150 and the optical sheet 180 . Since the backlight unit 100 according to an embodiment of the present invention emits light using the side light source 120 included in the light emitting cell 101 surrounded by the barrier rib 130, the light irradiation range is secured. It does not require a separate space (air gap) for Since the backlight unit 100 according to an embodiment of the present invention requires only a space equal to the height of the light source 120 between the reflective layer 150 and the optical sheet 180, it may have a thin thickness.

The planar shape surrounded by the barrier rib 130 becomes the planar shape of the light emitting cell 101 . That is, the planar shape of the light emitting cell 101 is defined by the barrier rib 130 . The planar shape of the light emitting cell 101 is not particularly limited. For example, the light emitting cell may have any one of a circular shape, an elliptical shape, and a polygonal shape on a plane. Referring to FIGS. 1 and 2 , the light emitting cell 101 has a rectangular planar shape.

The backlight unit 100 according to an embodiment of the present invention may further include a polymer resin 170 filled between the barrier ribs 130 . Specifically, the polymer resin 170 may fill the 3D space of the light emitting cell 101 defined by the barrier rib 130 and the reflective layer 150 . The polymer resin 170 may have light transmittance and may have a refractive index difference from other components of the backlight unit 100 . Due to this difference in refractive index, refraction of light may occur on the surface of the polymer resin 170, and the probability that the light generated from the light source 120 by the refraction of light travels upward and is emitted to the outside of the backlight unit 100 increases. can be increased

The polymer resin 170 may have a refractive index of 1.5 or more. When the refractive index of the polymer resin 170 is less than 1.5, the light extraction efficiency of the backlight unit 100 may not increase because the refractive index between the polymer resin 170 and other components is not high. For example, the polymer resin 170 may have a refractive index of 2.2 or less.

To improve light extraction efficiency, the polymer resin 170 may include light scattering particles. In addition, the polymer resin may include a phosphor. For example, when the light source 120 emits blue light, the polymer resin 170 may include a yellow phosphor so that light passing through the polymer resin 170 becomes white light.

Referring to FIG. 3 , an optical sheet 180 is disposed on the barrier rib 130 . Specifically, the optical sheet 180 may be disposed on the barrier rib 130 and the polymer resin 170 . At this time, the barrier rib 130 and the polymer resin 170 serve to support the optical sheet 180 .

The optical sheet 180 improves light efficiency of the backlight unit 100 . The optical sheet 180 may include, for example, a pattern sheet 181 such as a prism sheet and a diffusion plate 182 . However, an embodiment of the present invention is not limited thereto, and various other optical members commonly used in the backlight unit 100 may be used as the optical sheet 180 according to an embodiment of the present invention.

According to an embodiment of the present invention, a plurality of light sources 120 may be grouped into a plurality of light emitting blocks. Referring to FIG. 1, a plurality of light sources 120 are grouped into five light emitting blocks LB11, LB12, LB13, LB14, and LB15, and the plurality of light emitting blocks LB11, LB12, LB13, LB14, and LB15 are respectively has a line shape. Each of the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 includes at least one light source 120 . However, an embodiment of the present invention is not limited thereto, and the backlight unit 100 may include 6 or more light emitting blocks, and each light emitting block may have a shape other than a line.

The plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 may be independently turned on or off. More specifically, light emission of the light emitting block may be controlled by the printed circuit board 140 connected to the light source 120 . At this time, the light sources 120 included in the same light emitting blocks LB11, LB12, LB13, LB14, and LB15 are equally turned on and off, and included in the same light emitting blocks LB11, LB12, LB13, LB14, and LB15 that are different from each other. The light sources 120 may be turned on or off independently of each other.

Since each of the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 is independently turned on or off, local dimming driving to control the amount of light for each light emitting block is possible. In addition, the contrast ratio (CR) of the image is improved by controlling the amount of light of the light emitting block corresponding to the luminance of the image to be displayed on the display panel 190 . In addition, when displaying an image, all the light sources 120 included in the backlight unit 100 do not all emit light with the same intensity, but the light source 120 selectively emits light as much as necessary, so that the backlight unit 100 is driven. power is reduced Accordingly, power consumption of the display device using the backlight unit 100 may be reduced.

4 is a schematic plan view of a backlight unit 200 according to another embodiment of the present invention. Hereinafter, in order to avoid redundancy, descriptions of components already described are omitted.

The backlight unit 200 according to another embodiment of the present invention includes a base substrate 110, a plurality of light sources 120 disposed on the base substrate 110, and light emitting cells disposed on the base substrate 110 ( 102). The light emitting cell 102 defined by the barrier rib 130 includes at least one light source 120 .

Referring to FIG. 4 , a plurality of light sources 120 are grouped into nine light emitting blocks LB21 , LB22 , LB23 , LB24 , LB25 , LB26 , LB27 , LB28 , and LB29 . Each of the light emitting blocks LB21 , LB22 , LB23 , LB24 , LB25 , LB26 , LB27 , LB28 , and LB29 includes nine light sources 120 and nine light emitting cells 102 . The light sources 120 are arranged in a 3x3 matrix form in each of the light emitting blocks LB21 , LB22 , LB23 , LB24 , LB25 , LB26 , LB27 , LB28 , and LB29 .

Referring to FIG. 4 , a plurality of light emitting blocks LB21 , LB22 , LB23 , LB24 , LB25 , LB26 , LB27 , LB28 , and LB29 are also arranged in a matrix form. Local dimming using the backlight unit 200 may be implemented by controlling the light emission of each of the light emitting blocks LB21 , LB22 , LB23 , LB24 , LB25 , LB26 , LB27 , LB28 , and LB29 . The shape of the light emitting block and its arrangement may vary as needed.

5 is a partial plan view of a backlight unit 300 according to another embodiment of the present invention.

Referring to FIG. 5 , the light emitting cell 103 defined by the barrier rib 130 has a hexagonal planar shape. A plurality of light emitting cells 103 having a hexagonal planar shape are arranged in a honeycomb shape. Since the plurality of light sources 120 are displaced from each other in the vertical direction, vertical stripes do not occur in the backlight unit 300 .

6 is a schematic cross-sectional view of a display device 400 according to another exemplary embodiment of the present invention.

The display device 400 shown in FIG. 6 includes a backlight unit 100 and a display panel 190 disposed on the backlight unit 100 . The display panel 190 includes a first substrate 191, a second substrate 192 disposed to face the first substrate 191, and a liquid crystal disposed between the first substrate 191 and the second substrate 192. layer 190. The display panel 190 shown in FIG. 6 is a liquid crystal display panel, and the display device 400 shown in FIG. 6 is a liquid crystal display device.

The backlight unit 100 includes a base substrate 110, a plurality of light sources 120 disposed on the base substrate, and barrier ribs 130 disposed on the base substrate 110 to define light emitting cells 101. . The light emitting cell 101 includes at least one light source 120 , and the light source 120 emits light parallel to the surface of the base substrate 110 .

FIG. 6 shows a display device 400 using the backlight unit 100 according to an embodiment of the present invention shown in FIGS. 1 to 3 . However, the configuration of the display device 400 is not limited thereto, and the backlight units 200 and 300 shown in FIG. 4 or 5 may be used in the display device 400 of FIG. 6 .

In the backlight unit 100 shown in FIG. 6 , the plurality of light sources 120 are grouped into a plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 . Each of the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 may be disposed adjacent to a lower portion of the display panel 190 . Accordingly, the display panel 190 may be divided into a plurality of dimming regions along the direction in which the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 are arranged.

Since the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 are independently turned on or off, local dimming may be implemented in the display device 400 . In addition, the contrast ratio (CR) of the image is improved by controlling the amount of light of the plurality of light emitting blocks LB11 , LB12 , LB13 , LB14 , and LB15 in response to the luminance of the image to be displayed on the display panel 190 . In addition, when displaying an image, not all of the light sources 120 included in the backlight unit 100 emit light with the same intensity, but the light source 120 selectively emits light, so that the driving power of the backlight unit 100 is reduced. is reduced Accordingly, power consumption of the display device 400 is reduced.

Hereinafter, the present invention will be described in more detail with reference to comparative examples and examples.

7 is a schematic cross-sectional view of a backlight unit according to Comparative Example 1;

The backlight unit according to Comparative Example 1 includes a base substrate 110, a printed circuit board 140 disposed on the base substrate 110, a reflective layer 150 disposed on the printed circuit board 140, and a plurality of light sources 121. ) and an optical sheet 180 disposed on the plurality of light sources 121 .

The light source 121 shown in FIG. 7 is a direct type, and emits light toward the top of the drawing. The optical sheet 180 includes a prism pattern sheet 181 and a diffusion plate 182 .

In FIG. 7 , the light source 121 and the optical sheet 180 are spaced apart at a predetermined distance D. When the distance D between the light source 121 and the optical sheet 180 is small, light may not be irradiated to the area B between the two light sources 121 . On the other hand, when the distance D between the light source 121 and the optical sheet 180 is large, light may overlap the area B between the two light sources 121 . In addition, at a point far from the backlight unit, a light irradiated area and a non-illuminated area may not be clearly distinguished.

8A is an emission photograph of a backlight unit according to Comparative Example 1;

The backlight unit of Comparative Example 1 includes a plurality of light sources 121 arranged in a matrix shape similar to FIG. 1 , and does not include a barrier rib 130 . The light source 121 is a direct type. The plurality of light sources 121 are grouped in a line shape along the horizontal direction to form a plurality of light emitting blocks LB31, LB32, LB33, and LB34. 8A is taken with the first light emitting block LB31 and the third light emitting block LB33 turned off, and the second light emitting block LB32 and the fourth light emitting block LB34 turned on. It became. The left side of FIG. 8A is taken when the optical sheet 180 is not disposed, and the right side is taken when the optical sheet 180 is disposed.

Referring to FIG. 8A , the first light emitting block LB31 and the third light emitting block which are off due to the light emission of the second light emitting block LB32 and the fourth light emitting block LB34 which are on. It can be seen that the boundary of (LB33) is not clear. In particular, the third light emitting block LB33 is in a bright state due to the light emission of the second light emitting block LB32 and the fourth light emitting block LB34.

When the backlight unit according to Comparative Example 1 is used, it is difficult to implement local dimming and difficult to display a high dynamic range (HDR) image.

8B is a light emission picture of the backlight unit according to the first embodiment of the present invention. The backlight unit of Example 1 includes a plurality of light sources 120 arranged in a matrix form as in FIG. 1 . The light source 120 is a side light type. The plurality of light sources 120 are grouped in a line shape along the horizontal direction to form a plurality of light emitting blocks LB41, LB42, LB43, LB44, and 45. 8B , the first light emitting block LB41, the third light emitting block LB43, and the fifth light emitting block LB45 are on, and the second light emitting block LB42 and the fourth light emitting block LB44 are in an on state. is taken in an off state. The left side of FIG. 8B is taken when the optical sheet 180 is not disposed, and the right side is taken when the optical sheet 180 is disposed.

Referring to FIG. 8B , the boundary between the first light-emitting block LB41, the third light-emitting block LB43, and the fifth light-emitting block LB45 in an off state and the second light-emitting block (off) LB42) and the fourth light emitting block LB44 are relatively clearly distinguished. When the backlight unit according to the first embodiment is used, local dimming may be implemented and a high dynamic range (HDR) image may be displayed.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is in the technical field to which the present invention belongs that various substitutions, modifications, and changes are possible within the scope without departing from the technical details of the present invention. It will be clear to those skilled in the art. Therefore, the scope of the present invention is indicated by the claims to be described later, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims should be construed as being included in the scope of the present invention.

100, 200, 300: backlight unit
110: base 120: light source
130: bulkhead 140: printed circuit board
150: reflective layer 160: reflective pattern
170: polymer resin 180: optical sheet
400: display device

Claims (13)

base substrate;
a reflective layer disposed on the base substrate;
a plurality of light sources disposed on the reflective layer; and
A barrier rib disposed on the base substrate to define a light emitting cell;
the light emitting cell includes at least one of the light sources;
The light source is a side light type that emits light parallel to the surface of the base substrate,
Further comprising at least one reflective pattern disposed on the reflective layer,
The light emitting cells defined by the barrier ribs have a hexagonal planar shape, and a plurality of light emitting cells are arranged in a honeycomb shape.
backlight unit. According to claim 1,
The barrier rib surrounds the light source in a planar shape, the backlight unit. According to claim 1,
The barrier rib has light reflectivity, the backlight unit. According to claim 1,
The barrier rib has a height of 0.3 to 1.0 mm, the backlight unit. delete delete According to claim 1,
The backlight unit further comprises a polymer resin filled between the barrier ribs. According to claim 7,
The polymer resin has a refractive index of 1.5 or more, the backlight unit. According to claim 1,
Further comprising an optical sheet disposed on the barrier rib, the backlight unit. According to claim 1,
Further comprising a printed circuit board (PCB) disposed on the base substrate,
The light source is connected to the printed circuit board (PCB), the backlight unit. According to claim 1,
The plurality of light sources are grouped into a plurality of light emitting blocks,
Wherein each of the plurality of light emitting blocks includes at least one light source. According to claim 11,
The plurality of light emitting blocks are each independently turned on and off, the backlight unit. backlight unit; and
A display panel disposed on the backlight unit;
The display panel includes a first substrate, a second substrate disposed to face the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate;
The backlight unit,
base substrate;
a reflective layer disposed on the base substrate;
a plurality of light sources disposed on the reflective layer; and
A barrier rib disposed on the base substrate to define a light emitting cell;
the light emitting cell includes at least one of the light sources;
The light source emits light parallel to the surface of the base substrate,
Further comprising at least one reflective pattern disposed on the reflective layer,
The light emitting cells defined by the barrier ribs have a hexagonal planar shape, and a plurality of light emitting cells are arranged in a honeycomb shape.
display device.

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