Backlight unit

A backlight unit includes a light guide plate including a first surface and a second surface, opposite to the first surface, having a recess formed toward the first surface, and a light emitting device array disposed in the recess, the light emitting device array including a plurality of light emitting device packages and a board, on which the light emitting device packages are disposed. The light emitting device packages include first light emitting device packages to emit first light in the recess in a first direction, second light emitting device packages to emit second light in the recess in a second direction opposite to the first direction, and third light emitting device packages to emit third light having light output different from at least one of the first light and/or the second light in the recess in a third direction intersecting the first and second directions.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Korean Patent Application No. 10-2011-0079742, filed on Aug. 10, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

Embodiments relate to a backlight unit.

2. Description of the Related Art

A light emitting diode (LED) is a device that converts an electrical signal into light using the properties of a compound semiconductor. The LED is used in electric home appliances, remote controllers, electric bulletin boards, displays, various kinds of automated equipment, etc. The application range of LEDs continues to expand.

A backlight unit, to which light emitting diodes are applied, may be used in a display apparatus, such as a liquid crystal display apparatus, and lighting apparatuses for various other fields. Generally, the backlight unit may include a light emitting device package including a light emitting diode, a light guide plate to diffuse light emitted from the light emitting device package, and an optical sheet to diffuse or condense light emitted from the light guide plate.

The light emitting diode included in the light emitting device package of the backlight unit may be driven at low voltage with high efficiency. The light emitting diode is a two-terminal diode device including a compound semiconductor, such as gallium arsenide (GaAs), gallium nitride (GaN) or indium gallium nitride (InGaN). When power is applied to a cathode terminal and an anode terminal of the light emitting diode, the light emitting diode emits light energy generated during recombination between electrons and holes in the form of visible light.

Based on the position of the light emitting device package, the backlight unit is classified as an edge type backlight unit or a direct type backlight unit.

The edge type backlight unit is generally used in relatively small-sized liquid crystal display apparatuses, such as monitors for laptop computers and desktop computers. The edge type backlight unit has the effect of high light uniformity, long lifespan, and reducing the thickness of the liquid crystal display apparatuses.

In recent years, research has been carried out on a backlight unit configured to have not only an edge type structure but also a direct type structure.

SUMMARY

Embodiments provide a backlight unit that uniformly emits light in a central region and edge regions of a light guide plate.

In one embodiment, a backlight unit includes a light guide plate including a first surface and a second surface, opposite to the first surface, having a recess formed toward the first surface, and a light emitting device array disposed in the recess, the light emitting device array comprising a plurality of light emitting device packages and a board, on which the light emitting device packages are disposed, wherein the light emitting device packages include first light emitting device packages to emit first light in the recess in a first direction, second light emitting device packages to emit second light in the recess in a second direction opposite to the first direction, and third light emitting device packages to emit third light having light output different from at least one of the first light and/or the second light in the recess in a third direction intersecting the first and second directions.

In another embodiment, a backlight unit includes a light emitting device array including a plurality of light emitting device packages and a board, on which the light emitting device packages are disposed, and a light guide plate including a first surface and a second surface, opposite to the first surface, having a recess, in which the light emitting device array is disposed, formed toward the first surface, the second surface having a reflective pattern, wherein the light guide plate further includes a first region, located in a first direction of the recess, upon which first light emitted from first light emitting device packages of the light emitting device packages is incident, a second region located in a second direction of the recess, upon which second light emitted from second light emitting device packages of the light emitting device packages is incident, and a third region located in a third direction of the recess, upon which third light, emitted from third light emitting device packages of the light emitting device packages, having light output different from that of the first light and the second light, is incident.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. The present disclosure is defined only by the categories of the claims. In certain embodiments, detailed descriptions of device constructions or processes well known in the art may be omitted to avoid obscuring appreciation of the disclosure by a person of ordinary skill in the art. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Spatially-relative terms such as “below”, “beneath”, “lower”, “above”, or “upper” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that spatially-relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. Since the device may be oriented in another direction, the spatially-relative terms may be interpreted in accordance with the orientation of the device.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience of description and clarity. Also, the size or area of each constituent element does not entirely reflect the actual size thereof.

Angles or directions used to describe the structures of light emitting devices according to embodiments are based on those shown in the drawings. Unless there is, in the specification, no definition of a reference point to describe angular positional relations in the structures of the light emitting devices, the associated drawings may be referred to.

FIG. 1is an exploded perspective view showing a backlight unit100according to a first embodiment.

Referring toFIG. 1, the backlight unit100may include a light emitting device array110, a light guide plate120, and an optical sheet130.

The light emitting device array110may include a plurality of light emitting device packages112and a board, on which the light emitting device packages112are disposed, which will be described below in detail.

The light guide plate120may change point emission light emitted from the light emitting device packages112into surface emission light and provide the surface emission light to the optical sheet130.

That is, the light guide plate120may be formed of a polymethylmethacrylate (PMMA) or a transparent acryl resin and may be formed in a flat shape or in a wedge shape. The light guide plate120may be formed of glass; however, the disclosure is not limited thereto.

The transparent acryl resin exhibits high strength, and therefore, it is difficult to deform the transparent acryl resin. Also, the transparent acryl resin is lightweight and exhibits high visible light transmissivity.

The light guide plate120exhibits high visible light transmissivity, thereby preventing light from being non-uniformly transmitted through the whole area of the backlight unit100and thus preventing the occurrence of a phenomenon in which the edge of the backlight unit100is brighter.

Unevenness (not shown) may be formed at the rear of the light guide plate120to cause scattered reflection of light. The unevenness may be configured to have a predetermined shape in consideration of the distance from the light emitting device packages112.

Also, the unevenness may prevent light emitted from the light emitting device packages112from being concentrated upon opposite ends of the surface of the light guide plate120so that the entirety of the light guide plate120can uniformly emit light. A pattern obtained by forming the unevenness may provide surface emission light exhibiting high brightness and uniformity.

The light guide plate120may includes a first surface (not shown), on which the optical sheet130is disposed, and a second surface (not shown), opposite to the first surface, having a recess (not shown) formed toward the first surface.

In this case, the light guide plate120may include a first region (not shown) located in a first direction of the recess, a second region (not shown) located in a second direction of the recess, and a third region (not shown) located in a third direction of the recess.

In the embodiment, a recess v may be formed at the middle of the second surface in the shape of a line. At least one recess may be formed; however, the disclosure is not limited thereto.

That is, the recess v may be formed in a straight shape or in a cross shape to divide the second surface into at least two regions; however, the disclosure is not limited thereto.

The light emitting device array110is disposed in the recess v. The light emitting device packages112may include side view type light emitting device packages (not shown) and top view type light emitting device packages (not shown), which will be described below in detail.

The optical sheet130may include a diffusion film132, containing diffusion particles, such as beads, to diffuse light emitted from the light guide plate120toward a liquid crystal display panel (not shown), a prism film134having a prism pattern formed on the diffusion film132to concentrate light, and a protective film136stacked on the prism film134to protect the prism film134.

The optical sheet130may diffuse and condense light emitted from the light emitting device packages112and guided by the light guide plate120to secure brightness and a viewing angle.

The diffusion film132may diffuse and condense light emitted from the light emitting device packages112or light returning from the prism film134to achieve uniform brightness.

The diffusion film132may be formed in the shape of a thin sheet and may be formed of a transparent resin. For example, a film formed of polycarbonate or polyester may be coated with a light diffusion and condensing resin to form the diffusion film132.

The prism film134has a prism pattern vertically or horizontally formed at the surface of an optical film. The prism film124condenses light emitted from the diffusion film132.

The prism pattern of the prism film134may be formed in a triangular shape in section to improve light condensing efficiency. A right prism having a vertical angle of 90 degrees may provide excellent brightness.

The protective film136may be stacked on the prism film134to protect the prism film134.

A reflective sheet140may be formed on the second surface of the light guide plate120; however, the disclosure is not limited thereto. The reflective sheet140may upwardly reflect light emitted from the light emitting device packages112toward the light guide plate120to improve light transfer efficiency.

In the embodiment, a light reflective pattern may be formed at the second surface of the light guide plate120, and the diffusion film132is disposed on the first surface of the light guide plate120. Alternatively, a diffusion pattern (not shown) may be formed instead of the diffusion film132; however, the disclosure is not limited thereto.

FIGS. 2 and 3are perspective views showing first and second embodiments of the light emitting device array and the light guide plate shown inFIG. 1,FIG. 4is a perspective view showing first and second light emitting device packages shown inFIG. 2,FIG. 5is a perspective view showing a third light emitting device package shown inFIG. 2, andFIG. 6is a perspective view showing a first embodiment of the light emitting device array shown inFIG. 2.

Referring toFIGS. 2 to 6, the light emitting device array110may be disposed in the recess v of the light guide plate120.

In this case, the light guide plate120may include a first surface s1, on which the optical sheet130is disposed, and a second surface s2, opposite to the first surface s1, having a recess v.

Also, the light guide plate120may include a first region ss1located in a first direction (not shown) of the recess v, a second region ss2located in a second direction (not shown) of the recess v, and a third region ss3located in a third direction (not shown) of the recess v.

That is, the first region ss1may be located in a first lateral surface vd1of the recess v, the second region ss2may be located in a second lateral surface vd2of the recess and the third region ss3may be located in a third surface vd3of the recess v.

The first and second regions ss1and ss2may have a thickness of 1 mm to 2 mm, and the third region ss3may have a thickness of 0.45 mm to 0.75 mm.

That is, in the light guide plate120, at least one of the thicknesses of the first, second and third regions ss1, ss2and ss3may be different from the remainder of the thicknesses of the first, second and third regions ss1, ss2and ss3depending upon the depth of the recess v.

In this case, the thicknesses of the first, second and third regions ss1, ss2and ss3may be varied based on the thicknesses of first, second and third light emitting device packages112a,112band112c; however, the disclosure is not limited thereto.

The recess v may be formed in at least one selected from among a polygonal shape, an edge curved shape and a semicircular shape, and the recess v may be provided at the lower part thereof with a step (not shown) in which a board114of the light emitting device array110is disposed; however, the disclosure is not limited thereto.

In the embodiment shown inFIG. 2, the recess v is formed in a quadrangular shape in section. In the embodiment shown inFIG. 3, on the other hand, the recess v is formed in a semicircular shape in section.

In this case, the width (not shown) of the recess v may be equal to or less than the width (not shown) of the light emitting device array110, i.e. the board114; however, the disclosure is not limited thereto.

That is, the width of the recess v may be set to be equal to or less than that of the light emitting device array110to fix the board114, thereby preventing the light emitting device packages112from contacting the third surface vd3of the recess v.

The depth (not shown) of the recess v may be equal to or greater than the thickness (not shown) of the light emitting device array110; however, the disclosure is not limited thereto.

That is, the depth of the recess v may be one to three times the height of the light emitting device array110or one to three times the height of the light emitting device array110. For example, the depth of the recess v may be 0.55 mm to 1.25 mm; however, the disclosure is not limited thereto.

In other words, if the depth of the recess v is less than one times the height of the light emitting device packages112or less than 0.55 mm, light emitted from the light emitting device packages112leaks to under the second surface s2of the light guide plate120, i.e. light leakage may occur. On the other hand, if the depth of the recess v is greater than three times the height of the light emitting device packages112or greater than 1.25 mm, the thickness of the light guide plate120between the first and second surfaces s1and s2is increased with the result that it is difficult to obtain a slim light guide plate.

The light emitting device array110may include a plurality of light emitting device packages112and a board114, on which the light emitting device packages112are disposed.

The board114may be a printed circuit board, a flexible printed circuit board or a metal core PCB (MCPCB). A single-sided printed circuit board (PCB), a double-sided printed circuit board (PCB), or a multi-layered printed circuit board (PCB) may be used as the printed circuit board. In the embodiment, the printed circuit board is used as the board114; however, the disclosure is not limited thereto.

The light emitting device packages112may include first, second and third light emitting device packages112a,112band112c.

The first and second light emitting device packages112aand112bmay be side view type light emitting device packages and may have the same construction; however, the disclosure is not limited thereto.

The first and second light emitting device packages112aand112bshown inFIGS. 2 and 3have the same construction.FIG. 4shows the first light emitting device package112ain detail.

Referring toFIG. 4, a first light emitting device package112amay include a light emitting device11and a package body12in which the light emitting device11is disposed.

The package body12may be formed of at least one selected from among a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), AlOx, liquid crystal polymer, photo sensitive glass (PSG), polyamide 9T (PA9T), syndiotactic polystyrene (SPS), a metallic material, sapphire (Al2O3), beryllium oxide (BeO), ceramic and a printed circuit board (PCB).

The package body12may be formed by injection molding or etching; however, the disclosure is not limited thereto.

The upper surface of the package body12may be formed in various shapes, such as a triangular shape, a quadrangular shape, a polygonal shape and a circular shape, based on use or design of the light emitting device11; however, the disclosure is not limited thereto.

Also, the package body12may have a cavity s, in which the light emitting device11is disposed. The cavity s may be formed in a cup shape or a concave container shape in section. The inner side surface of the package body12defining the cavity s may be inclined downward.

Also, the cavity s may be formed in various shapes, such as a circular shape, a quadrangular shape, a polygonal shape and an oval shape, in plan; however, the disclosure is not limited thereto.

First and second lead frames13and14may be disposed at the lower surface of the package body12. The first and second lead frames13and14may be formed of at least one selected from among titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chrome (Cr), tantalum (Ta), platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium (Ge), hafnium (Hf), ruthenium (Ru) and iron (Fe) or an alloy thereof.

Also, the first and second lead frames13and14may be formed to have a single layer structure or a multi layer structure; however, the disclosure is not limited thereto.

The inner side surface of the package body12may be formed at a predetermined inclination angle with respect to one of the first and second lead frames13and14. A reflection angle of light emitted from the light emitting device11may be varied based on the inclination angle of the inner side surface of the package body12, thereby adjusting a viewing angle of light emitted outward. If a viewing angle of light decreases, concentration of light emitted from the light emitting device11increases. On the other hand, if a viewing angle of light increases, concentration of light emitted from the light emitting device11decreases.

The inner side surface of the package body12may have a plurality of inclination angles; however, the disclosure is not limited thereto.

The first and second lead frames13and14may be electrically connected to the light emitting device11and connected to an anode (positive electrode) and a cathode (negative electrode) of an external power source (not shown) to supply power to the light emitting device11.

The light emitting device11is mounted on the first lead frame13. The light emitting device11is connected to the first lead frame13by die bonding. Also, the light emitting device11is connected to the second lead frame14by wire bonding using a wire (not shown). As a result, power is supplied to the light emitting device11via the first and second lead frames13and14.

The light emitting device11may be connected to the first and second lead frames13and14by wire bonding or die bonding; however, the disclosure is not limited thereto.

Also, a cathode mark (not shown) may be formed at the package body12. The cathode mark may be used to distinguish between polarities of the light emitting device11, i.e. polarities of the first and second lead frames13and14. Consequently, the cathode mark may be used to prevent confusion when the first and second lead frames13and14are electrically connected.

An insulative dam16may be formed between the first and second lead frames13and14to prevent the occurrence of a short circuit between the first and second lead frames13and14.

The light emitting device11may be a light emitting diode. For example, the light emitting diode may be a colored light emitting diode to emit red, green, blue or white light or an ultraviolet (UV) light emitting diode to emit UV light; however, the disclosure is not limited thereto. Also, a plurality of light emitting devices11may be mounted on the first lead frame13, and at least one light emitting device11may be mounted on the first and second lead frames13and14. However, the number and mounted positions of the light emitting devices11are not limited.

In the embodiment, a blue light emitting device to emit blue light is used as the light emitting device11.

Also, the package body12may include a resin member filled in the cavity s. The resin member18may be formed to have a double or triple mold structure; however, the disclosure is not limited thereto.

The resin member18may be formed in a film shape and may contain a fluorescent substance and/or a light dispersing agent. Alternatively, the resin member18may be formed of a light transmitting material which does not contain a fluorescent substance and a light dispersing agent; however, the disclosure is not limited thereto.

That is, if the first light emitting device package112aemits white light, the fluorescent substance may be a red fluorescent substance and a green fluorescent substance. In this case, the light emitting device11may emit blue light.

If the light emitting device11emits red or green light, a blue fluorescent substance and a green fluorescent substance or a blue fluorescent substance and a red fluorescent substance may be mixed so that the first light emitting device package112acan emit white light.

Referring back toFIG. 2, the first light emitting device packages112amay be disposed adjacent to the first lateral surface vd1of the recess v to emit first light toward the first region ss1, and the second light emitting device packages112bmay be disposed adjacent to the second lateral surface vd2of the recess v to emit second light toward the second region ss2.

That is, the first and second light emitting device packages112aand112bmay emit the first and second lights in first and second directions which are opposite to each other to diffuse light to the first and second regions ss1and ss2, respectively.

The third light emitting device packages112cmay be top view type light emitting device packages to emit third light having light output different from that of the first light and/or the second light to the third surface vd3of the recess v.

The third light emitting device packages112cmay emit the third light, which has light output less than that of the first light and the second light, to the third region ss3, which has an area less than that of the first and second regions ss1and ss2.

In this case, the light guide plate120may uniformly diffuse light from the first, second and third regions ss1, ss2and ss3to the optical sheet120disposed on the first surface s1.

If the area of the first region ss1is equal to or greater than that of the second region ss2, the first light of the first light emitting device packages112amay have light output equal to or greater than the second light of the second light emitting device packages112b. Also, the first light of the first light emitting device packages112amay have different light outputs depending on the areas of the first region ss1and the second region ss2; however, the disclosure is not limited thereto.

Referring toFIG. 5, a third light emitting device package112cmay include a light emitting device21and a package body22in which the light emitting device21is disposed.

The package body22may include a first partition wall (not shown) disposed in a first direction (not shown) and a second partition wall (not shown) disposed in a second direction intersecting the first direction. The first partition wall and the second partition wall may be integrally formed. The package body22may be formed by injection molding or etching; however, the disclosure is not limited thereto.

The package body22may be formed of at least one selected from among a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), AlOx, liquid crystal polymer, photo sensitive glass (PSG), polyamide 9T (PA9T), syndiotactic polystyrene (SPS), a metallic material, sapphire (Al2O3), beryllium oxide (BeO), ceramic and a printed circuit board (PCB).

The upper surface of the package body22may be formed in various shapes, such as a triangular shape, a quadrangular shape, a polygonal shape and a circular shape, based on use or design of the light emitting device21; however, the disclosure is not limited thereto.

Also, the package body22may have a cavity s1, in which the light emitting device21is disposed. The cavity s1may be formed in a cup shape or a concave container shape in section. The inner side surface of the package body22defining the cavity s1may be inclined downward.

Also, the cavity s1may be formed in various shapes, such as a circular shape, a quadrangular shape, a polygonal shape and a circular shape, in plan; however, the disclosure is not limited thereto.

First and second lead frames23and24may be disposed at the lower surface of the package body22. The first and second lead frames23and24may be formed of at least one selected from among titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chrome (Cr), tantalum (Ta), platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium (Ge), hafnium (Hf), ruthenium (Ru) and iron (Fe) or an alloy thereof.

Also, the first and second lead frames23and24may be formed to have a single layer structure or a multi layer structure; however, the disclosure is not limited thereto.

The inner side surface of the package body22may be formed at a predetermined inclination angle with respect to one of the first and second lead frames23and24. A reflection angle of light emitted from the light emitting device21may be varied based on the inclination angle of the inner side surface of the package body22, thereby adjusting a viewing angle of light emitted outward. If a viewing angle of light decreases, concentration of light emitted from the light emitting device21increases. On the other hand, if a viewing angle of light increases, concentration of light emitted from the light emitting device21decreases.

The inner side surface of the package body22may have a plurality of inclination angles; however, the disclosure is not limited thereto.

The first and second lead frames23and24may be electrically connected to the light emitting device21and connected to an anode (positive electrode) and a cathode (negative electrode) of an external power source (not shown) to supply power to the light emitting device21.

In the embodiment, the light emitting device21is mounted on the first lead frame23, and the second lead frame24is spaced apart from the first lead frame23. The light emitting device21is connected to the first lead frame23by die bonding. Also, the light emitting device is connected to the second lead frame24by wire bonding using a wire (not shown). As a result, power is supplied to the light emitting device21via the first and second lead frames23and24.

The light emitting device21may be bonded to the first and second lead frames23and24with different polarities.

Also, the light emitting device21may be connected to the first and second lead frames23and24by wire bonding or die bonding; however, the connection method is not limited thereto.

In the embodiment, the light emitting device21is disposed on the first second lead frame23; however, the disclosure is not limited thereto.

Also, the light emitting device21may be joined to the first second lead frame23by an adhesive member (not shown).

An insulative dam26may be formed between the first and second lead frames23and24to prevent the occurrence of a short circuit between the first and second lead frames23and24.

In the embodiment, the upper part of the insulative dam26may be formed in a semicircular shape; however, the disclosure is not limited thereto.

A cathode mark17may be formed at the package body22. The cathode mark17may be used to distinguish between polarities of the light emitting device21, i.e. polarities of the first and second lead frames23and24. Consequently, the cathode mark17may be used to prevent confusion when the first and second lead frames23and24are electrically connected.

The light emitting device21may be a light emitting diode. For example, the light emitting diode may be a colored light emitting diode to emit red, green, blue or white light or an ultraviolet (UV) light emitting diode to emit UV light; however, the disclosure is not limited thereto. Also, a plurality of light emitting devices21may be mounted on the first lead frame23, and at least one light emitting device21may be mounted on the first and second lead frames23and24. However, the number and mounted positions of the light emitting devices21are not limited.

Also, the package body22may include a resin member filling the cavity s1. The resin member28may be formed to have a double or triple mold structure; however, the disclosure is not limited thereto.

The resin member28may be formed in a film shape and may contain a fluorescent substance and/or a light dispersing agent. Alternatively, the resin member28may be formed of a light transmitting material which does not contain a fluorescent substance and a light dispersing agent; however, the disclosure is not limited thereto.

Referring toFIG. 6, the light emitting device array110may include first, second and third light emitting device packages112a,112band112cand a board114, on which the first, second and third light emitting device packages112a,112band112care disposed.

The board114may include a central region c and first and second edge regions e1and e2adjacent to first and second sides (not shown) of the board114in a state in which the central region c is disposed between the first and second edge regions e1and e2.

In the first and second edge regions e1and e2, the first, second and third light emitting device packages112a,112band112cmay be disposed on the board114in a first pattern. In the central region c, the first, second and third light emitting device packages112a,112band112cmay be disposed on the board114in a second pattern.

In the first pattern, the first, second and third light emitting device packages112a,112band112cmay be disposed in a triangular shape, and the third light emitting device packages112cmay be disposed adjacent to the first and second sides of the board114.

That is, the third light emitting device packages112cmay be disposed adjacent to the first and second sides of the board114so that light is dispersed toward the first surface s1in addition to the first and second edge regions ss1and ss2, thereby preventing the occurrence of a dark region.

The third light emitting device packages112cmay be spaced apart from extension lines of the first and second light emitting device packages112aand112bby a first distance d1.

In the embodiment, the first distance d1may be a straight distance between each of the third light emitting device packages112cand one side of a corresponding one of the second light emitting device packages112b. Alternatively, the third light emitting device packages112cmay be spaced apart from the first and second light emitting device packages112aand112bin a diagonal direction.

In the second pattern, the first, second and third light emitting device packages112a,112band112cmay be disposed in line, and each of the third light emitting device packages112cmay be disposed between a corresponding one of the first light emitting device packages112aand a corresponding one of the second light emitting device packages112b.

In this case, each of the third light emitting device packages112cmay be spaced apart from a corresponding one of the first light emitting device packages112aand a corresponding one of the second light emitting device packages112bby a second distance d2.

In the embodiment, the second distance d2may be a straight distance between each of the third light emitting device packages112cand one side of a corresponding one of the first light emitting device packages112a.

In this case, the distance between each of the third light emitting device packages112c, disposed in the second pattern, adjacent to the first and second edge regions e1and e2and a corresponding one of the first light emitting device packages112aor the second light emitting device packages112bdisposed in the first pattern may be the first distance d1; however, the disclosure is not limited thereto.

If the areas of the first and second regions ss1and ss2shown inFIG. 2are equal to each other, the first and second light emitting device packages112aand112bmay have the same package size. On the other hand, if the area of the first region ss1is less than that of the second region ss2, the package size of each of the first light emitting device packages112amay be less than that of each of the second light emitting device packages112b.

Also, luminous intensity of each of the first light emitting device packages112amay be equal to or less than that of each of the second light emitting device packages112b. The luminous intensities of the first light emitting device packages112aand the second light emitting device packages112bmay be set based on the areas of the first and second regions ss1and ss2; however, the disclosure is not limited thereto.

The first and second light emitting device packages112aand112bdisposed on the board114may be connected to each other in parallel, and the first and second light emitting device packages112aand112bmay be connected to the third light emitting device packages112cin series; however, the disclosure is not limited thereto.

Also, the first and second light emitting device packages112aand112bmay be symmetrically disposed in a state in which the third light emitting device packages112care disposed respectively between the first and second light emitting device packages112aand112b.

At least one of the first, second and third light emitting device packages112a,112band112cmay emit at least one selected from among white light W, red light R, green light G, blue light B and yellow light Y; however, the disclosure is not limited thereto.

FIGS. 7 and 8are perspective views showing second and third embodiments of the light emitting device array shown inFIG. 2, respectively.

Components of light emitting device arrays shown inFIGS. 7 and 8identical to those of the light emitting device array shown inFIG. 6will not be described or will be briefly described.

Referring toFIG. 7, a light emitting device array210may include a central region c10and first and second edge regions e11and e12adjacent to first and second sides of a board214in a state in which the central region c10is disposed between the first and second edge regions e11and e12.

In the first and second edge regions e11and e12, first, second and third light emitting device packages212a,212band212cmay be disposed in a first pattern. In the central region c10, the first, second and third light emitting device packages212a,212band212cmay be disposed in a second pattern.

In the embodiment, the second pattern of the central region c10is identical to that of the central region c shown inFIG. 6, and therefore, a description thereof will be omitted.

In the first pattern, a third light emitting device package212cmay be disposed adjacent to each of the first and second sides of the board214, and a second light emitting device package212band a first light emitting device package212amay be sequentially disposed adjacent to the third light emitting device package212c.

In the first and second edge regions e11and e12, a third distance d3between the second and third light emitting device package212band212cmay be equal to or greater than a fourth distance d4between the first and second light emitting device package212aand212b; however, the disclosure is not limited thereto.

Referring toFIG. 8, a light emitting device array310may include a central region c20and first and second edge regions e21and e22adjacent to first and second sides of a board314in a state in which the central region c20is disposed between the first and second edge regions e21and e22.

In the first and second edge regions e21and e22, first, second and third light emitting device packages312a,312band312cmay be disposed in a first pattern. In the central region c20, the first, second and third light emitting device packages312a,312band312cmay be disposed in a second pattern.

In the embodiment, the first pattern of the first and second edge regions e21and e22is identical to that of the first and second edge regions e1and e2shown inFIG. 6, and therefore, a description thereof will be omitted.

The first pattern may be identical to the second pattern; however, the distances among the first, second and third light emitting device packages312a,312band312caccording to the first pattern may be different from those among the first, second and third light emitting device packages312a,312band312cin the second pattern.

That is, in the central region c20, the first, second and third light emitting device packages312a,312band312cmay be disposed so as to much more improve concentration of light than in the first and second edge regions e21and e22.

In other words, a fifth distance d5between each of the third light emitting device packages312cand a corresponding one of the first light emitting device packages312aor a corresponding one of the second light emitting device packages312bin the first and second edge regions e21and e22is set to be greater than a sixth distance d6between each of the third light emitting device packages312cadjacent to the first and second edge regions e21and e22and a corresponding one of the first light emitting device packages312aor a corresponding one of the second light emitting device packages312bin the central region c20, thereby improving concentration of light in the central region c20.

FIG. 9is an exploded perspective view showing a liquid crystal display apparatus400including a backlight unit according to an embodiment.

Referring toFIG. 9, the liquid crystal display apparatus400may include a liquid crystal display panel410and a backlight unit470to supply light to the liquid crystal display panel410.

The liquid crystal display panel410may display an image using light emitted from the backlight unit470. The liquid crystal display panel410may include a color filter substrate412and a thin film transistor substrate414disposed opposite to each other in a state in which a liquid crystal is disposed between the color filter substrate412and the thin film transistor substrate414.

The color filter substrate412may realize colors of the image displayed through the liquid crystal display panel410.

The thin film transistor substrate414is electrically connected to a printed circuit board418, on which a plurality of circuit parts is mounted, via drive films417. The thin film transistor substrate414may apply drive voltage supplied from the printed circuit board418to the liquid crystal in response to a drive signal provided by the printed circuit board418.

The thin film transistor substrate414may include a thin film transistor and a pixel electrode formed on another transparent substrate, such as a glass or plastic substrate.

The backlight unit470includes a light emitting device array420to emit light, a light guide plate430to change the light emitted from the light emitting device array420into surface emission light and to provide the surface emission light to the liquid crystal display panel410, a plurality of films450,466and466to uniformalize brightness distribution of the light provided from the light guide plate430, thereby improving vertical incidence of light, and a reflective sheet440to reflect light emitted to the rear of the light guide plate430toward the light guide plate430.

The light emitting device array420may include a plurality of light emitting device packages424and a PCB422on which the light emitting device packages424are mounted to constitute the light emitting device array420.

Meanwhile, the backlight unit470may further include a diffusion film466to diffuse the light emitted from the light guide plate430toward the liquid crystal display panel410and a prism film450to condense the diffused light, thereby improving vertical incidence of light. Also, the backlight unit470may further include a protective film464to protect the prism film450.

As is apparent from the above description, the backlight unit according to each of the embodiments is configured so that a groove is formed at the rear of a light guide plate, and side view type light emitting device packages to emit light to opposite lateral surfaces of the groove and top view type light emitting device packages to emit light to the upper surface of the groove are disposed in the groove, thereby uniformly emitting light in a central region and edge regions of the light guide plate.

Also, the backlight unit according to each of the embodiments is configured so that light emitting device packages and a board, on which the light emitting device packages are disposed, are disposed in the light guide plate, thereby reducing the area of the backlight unit.

Particular features, structures, or characteristics described in connection with the embodiment are included in at least one embodiment of the present disclosure and not necessarily in all embodiments. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present disclosure may be combined in any suitable manner with one or more other embodiments or may be changed by those skilled in the art to which the embodiments pertain. Therefore, it is to be understood that contents associated with such combination or change fall within the spirit and scope of the present disclosure.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and applications may be devised by those skilled in the art that will fall within the intrinsic aspects of the embodiments. More particularly, various variations and modifications are possible in concrete constituent elements of the embodiments. In addition, it is to be understood that differences relevant to the variations and modifications fall within the spirit and scope of the present disclosure defined in the appended claims.