CN111308778A

CN111308778A - Backlight unit and display device including the same

Info

Publication number: CN111308778A
Application number: CN201911240941.1A
Authority: CN
Inventors: 金东辉; 金基圣; 尹赫晙; 权昇注
Original assignee: LG Display Co Ltd
Current assignee: LG Display Co Ltd
Priority date: 2018-12-11
Filing date: 2019-12-06
Publication date: 2020-06-19
Anticipated expiration: 2039-12-06
Also published as: TW202026726A; KR20200071651A; CN111308778B; TWI736046B

Abstract

Embodiments of the present disclosure relate to a backlight unit and a display device including the same. In an embodiment, a backlight unit includes a light emitting device and a lower reflector on a substrate. The lower reflector has a hole to receive the light emitting device and to expose the light emitting device. The lower reflector may have a height greater than a height of the light emitting device. The backlight unit may include a colored resin in the hole and on the light emitting device. The backlight unit may include an optical path modulator above the light emitting device and on the colored resin. The optical path modulator may have a refractive index different from that of the colored resin to reflect the emitted light toward the lower reflector at a boundary of the optical path modulator and the colored resin.

Description

Backlight unit and display device including the same

Cross Reference to Related Applications

This application claims priority from korean patent application No. 10-2018-.

Technical Field

Embodiments disclosed herein relate to a backlight unit and a display device including the same.

Background

A Liquid Crystal Display (LCD) is one of flat panel displays for displaying images using liquid crystals. LCDs are widely used throughout the industry due to their advantages such as thin thickness, light weight, and low power consumption. The LCD can display an image by adjusting transmittance of light emitted from the backlight unit according to its characteristic of controlling transmittance by changing arrangement of liquid crystals. Such an LCD uses Light Emitting Diodes (LEDs), Cold Cathode Fluorescent Lamps (CCFLs), hot cathode fluorescent lamps (HCLFs), etc. as light sources of a backlight unit. In recent years, light emitting diodes having excellent light efficiency and high color reproducibility have been widely used as light sources for backlight units.

The backlight unit may be classified into an edge type or a direct type according to the arrangement of the light sources and the light transmission form. In the direct type backlight unit, a light source such as an LED may be disposed at a rear side of the display device.

The light source device used in such a direct type backlight unit may include a light emitting diode and a substrate on which the light emitting diode is mounted and which includes a circuit element for driving the light emitting diode and the like. In addition, a phosphor film including an expensive phosphor may be disposed on the light emitting diode such that light emitted from the light emitting device is excited to represent color. However, since a large amount of phosphor is used in the phosphor film, the manufacturing cost of the backlight unit may increase. In addition, when light emitted from the light emitting device is not sufficiently excited, color reproducibility deteriorates.

Disclosure of Invention

Embodiments of the present disclosure provide a backlight unit having high color reproducibility and a display device including the same.

In addition, embodiments of the present disclosure provide a backlight unit capable of reducing manufacturing costs and a display device including the same.

According to the embodiments of the present disclosure, a backlight unit having high color reproducibility and a display device including the same may be provided.

According to the embodiments of the present disclosure, a backlight unit capable of reducing manufacturing costs and a display device including the same may be provided.

In various embodiments, a backlight unit includes: a substrate; a light emitting device on the substrate; a lower reflector on the substrate, the lower reflector having an aperture to receive and expose the light emitting device, the lower reflector having a height greater than a height of the light emitting device and configured to reflect light emitted from the light emitting device; a colored resin in the hole and on the light emitting device, the colored resin having a height lower than a height of the lower reflector; and an optical path modulator above the light emitting device and on the colored resin, the optical path modulator having a refractive index different from a refractive index of the colored resin to reflect the emitted light toward the lower reflector at a boundary of the optical path modulator and the colored resin.

In an embodiment, the colored resin includes a plurality of phosphors having at least two different colors. In an embodiment, the colored resin has an upper surface that is concave or convex.

In an embodiment, the optical path modulator comprises air.

In an embodiment, the backlight unit further comprises a distributed bragg reflector on the light emitting device, the distributed bragg reflector being in the hole and between the substrate and the optical path modulator.

In an embodiment, the backlight unit further includes: an adhesive film on the lower reflector and the optical path modulator; and a light-modifying sheet on the adhesive film, the light-modifying sheet comprising a plurality of light-modifying patterns, at least one of the plurality of light-modifying patterns at least partially overlapping the light-emitting device and having one or more layers, the one or more layers comprising a top layer on a surface of the light-modifying sheet facing the substrate, there being an air gap between the one or more layers and the adhesive film.

In an embodiment, the one or more layers further comprise an intermediate layer on a surface of the top layer facing the substrate, the top layer having a dimension larger than a dimension of the intermediate layer.

In an embodiment, the one or more layers further comprise a bottom layer on a surface of the intermediate layer facing the substrate, the bottom layer having a size smaller than a size of the intermediate layer.

In an embodiment, the backlight unit further includes: a phosphor film on the light-modifying sheet; a diffusion plate on the phosphor film; and an optical sheet on the diffusion plate.

In various embodiments, a backlight unit includes: a substrate including a trench having sidewalls coated with a reflective material and having a first height; a light emitting device in the trench, the light emitting device having a second height lower than the first height; a colored resin in the groove and on the light emitting device, the colored resin having a third height lower than the first height; and an optical path modulator in the groove and on the colored resin, the optical path modulator having a refractive index different from a refractive index of the colored resin to reflect light emitted from the light emitting device toward a sidewall of the groove at a boundary of the optical path modulator and the colored resin.

In various embodiments, a method for manufacturing a backlight unit includes: disposing a plurality of light emitting devices in a region of a substrate; providing a lower reflector on the substrate, wherein a hole of the lower reflector receives and exposes the plurality of light emitting devices, the hole having a depth greater than a height of the plurality of light emitting devices; curing the colored resin in the pores, the cured resin having a height less than the depth; an optical path modulator is provided in the hole and on the colored resin, the optical path modulator having a refractive index different from that of the colored resin.

In an embodiment, the method further comprises: disposing a reflector on the plurality of light emitting devices; and coating the substrate with a reflective material.

In an embodiment, the method further comprises: disposing an adhesive film on the lower reflector and the optical path modulator; and disposing a light-modifying sheet on the adhesive film, the light-modifying sheet including a plurality of light-modifying patterns at least partially overlapping the plurality of light-emitting devices, respectively, at least one of the plurality of light-modifying patterns having one or more layers including a top layer on a surface of the light-modifying sheet facing the substrate, with an air gap between the one or more layers and the adhesive film.

In an embodiment, the method further comprises printing a top layer on a surface of the light-modifying sheet.

In an embodiment, the method further comprises printing an intermediate layer of the one or more layers on a top layer, the top layer having a larger area than the area of the intermediate layer, wherein the light-modifying sheet with the printed top layer and intermediate layer is inverted before the light-modifying sheet is disposed on the adhesive film.

In an embodiment, the method further comprises printing a bottom layer of the one or more layers on the middle layer, the bottom layer having a smaller area than an area of the middle layer.

In various embodiments, a backlight unit includes: a light emitting device having a flip chip structure; a first reflector disposed to surround a first region including the light emitting device and a periphery of the light emitting device; a colored resin disposed in the first region; an adhesive film disposed over the colored resin to be spaced apart from the colored resin by a predetermined distance; and a light-modifying sheet disposed on the adhesive film, the light-modifying sheet including a light-modifying pattern disposed to correspond to a position of the light-emitting device.

In an embodiment, the backlight unit further includes: a material disposed between the adhesive film and the colored resin, the material having a refractive index different from a refractive index of the colored resin.

In an embodiment, the first reflector has a height higher than a height of the colored resin.

In an embodiment, the backlight unit further includes: a substrate including a groove corresponding to the first region, and wherein the reflective film is applied to the substrate.

In an embodiment, the backlight unit further includes: a phosphor film disposed over the light-modifying sheet, the phosphor film including a phosphor having a color different from a color of the colored resin.

In an embodiment, the colored resin includes two types of phosphors having different colors.

In an embodiment, the backlight unit further includes a second reflector disposed on an upper surface of the light emitting device.

In various embodiments, a display device includes: a liquid crystal panel; a backlight unit disposed below the liquid crystal panel, the backlight unit being configured to radiate light toward the liquid crystal panel. The backlight unit includes: a light emitting device having a flip chip structure; a first reflector disposed to surround a first region including the light emitting device and a periphery of the light emitting device; a colored resin disposed in the first region; an adhesive film disposed over the colored resin to be spaced apart from the colored resin by a predetermined distance; and a light-modifying sheet disposed on the adhesive film, the light-modifying sheet including a light-modifying pattern disposed to correspond to a position of the light-emitting device.

Drawings

The foregoing and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

fig. 1 is a block diagram illustrating a display device according to an embodiment of the present disclosure.

Fig. 2 is a view illustrating an example of a structure of a backlight unit included in a display device according to an embodiment of the present disclosure.

Fig. 3A to 3E are views each showing an example of a specific structure of the backlight unit shown in fig. 2.

Fig. 4 is a view illustrating a structure of a backlight unit according to an embodiment of the present disclosure.

Fig. 5A and 5B are views illustrating an example of a structure according to positions of light modification patterns included in the backlight unit illustrated in fig. 4.

Fig. 6 is a structural view illustrating an embodiment of the backlight unit shown in fig. 1.

Fig. 7 is a perspective view illustrating a reflector employed in the backlight unit shown in fig. 1.

Fig. 8 is a conceptual diagram illustrating a path of light emitted from the light emitting device.

Fig. 9A to 9F are conceptual views illustrating a process of manufacturing the backlight unit illustrated in fig. 6.

Fig. 10 is a structural view illustrating an embodiment of the backlight unit shown in fig. 1.

Fig. 11 is a structural view illustrating an embodiment of the backlight unit shown in fig. 1.

Detailed Description

Advantages and features of the present disclosure and methods of accomplishing the same will become apparent by reference to the following detailed description of embodiments of the disclosure when taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following embodiments are provided only for complete disclosure of the present disclosure and to inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the appended claims.

Shapes, sizes, ratios, angles, numbers, and the like, which are shown in the drawings to explain embodiments of the present disclosure, are exemplary, and thus the present disclosure is not limited to the shown contents. Throughout the specification, the same or similar reference numerals denote the same or similar elements. Further, in the description of the present disclosure, when it is determined that a detailed description of a related well-known technology unnecessarily makes the subject matter of the present disclosure unclear, the detailed description will be omitted. When the expressions "comprising", "having", "including", etc. as mentioned herein are used, any other component may be added unless the expression "only" is used. When an element is referred to in the singular, the element can be in the plural unless the element is specifically referred to.

Further, in explaining elements in the embodiments of the present disclosure, the elements in the embodiments of the present disclosure should be construed to cover the tolerance range even if explicit indications are not given individually.

Additionally, when describing components of the present disclosure, terms such as first, second, A, B, (a), (b), etc. may be used herein. Each of these terms is not intended to define the nature, order, or sequence of the corresponding elements, but rather is intended to distinguish the corresponding element from one or more other elements. Where a structural element is described as being "connected to," "coupled to," or "in contact with" another structural element, it should be construed that another structural element may be "connected to," "coupled to," or "in contact with" the structural element and that a structural element is directly connected to or in contact with another structural element. When the positional relationship of two components is described using, for example, "on … …," "above … …," "below … …," "beside … …," etc., one or more other components may be positioned between the two components unless a term such as "only" or "directly" is used.

In addition, components in the embodiments of the present disclosure are not limited by these terms. These terms are only used to distinguish one element from another. Therefore, when a constituent element is hereinafter referred to as a first constituent element, the constituent element may be a second constituent element within the technical idea of the present disclosure.

In addition, features (components) in the embodiments of the present disclosure may be partially or entirely coupled or combined with each other or may be partially or entirely separated from each other, various interlocks and actuations in technology may be possible, and the respective embodiments may be implemented independently of each other or may be implemented in combination with each other.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Referring to fig. 1, the display device 10 may include a display panel 100, for example, a liquid crystal panel, and a backlight unit 200 configured to radiate light to the display panel 100.

The display panel 100 may be a liquid crystal panel. The liquid crystal panel may include: a liquid crystal layer capable of generating a difference in transmittance according to an arrangement of liquid crystal molecules; a pixel electrode configured to selectively apply a voltage to the liquid crystal layer; and a common electrode configured to apply a common voltage to the liquid crystal layer. The liquid crystal layer may be disposed between the pixel electrode and the common electrode, and an arrangement of liquid crystal molecules may be determined according to a voltage applied between the pixel electrode and the common electrode. In addition, the display panel 100 may include a color filter. In addition, the display panel 100 may further include: a pixel circuit configured to selectively apply a voltage to the pixel electrode; and a driving circuit configured to supply a signal and a voltage to the pixel circuit.

The backlight unit 200 is disposed under the display panel 100 and may uniformly radiate light from under the display panel 100 to at least a portion or the entire face of the display panel 100. The backlight unit 200 may generate and radiate light using light emitting diodes. The backlight unit 200 may be spaced apart from the display panel 100 by a predetermined distance d 1.

Referring to fig. 2, the display device 10 according to an embodiment of the present disclosure may include: a display panel 100; and a backlight unit 200, the backlight unit 200 being disposed under the display panel 100 and configured to provide light to the display panel 100.

Various structures may be disposed between the backlight unit 200 and the display panel 100. For example, the display panel 100 may be fixed to the backlight unit 200 via the guide plate 400, the foam pad 500, and the like, but the present disclosure is not limited thereto.

The backlight unit 200 may include a cover bottom 300 configured to receive optical elements and the like constituting the backlight unit 200.

A substrate 210 may be disposed on the cover bottom 300 and a plurality of light emitting devices 211 may be disposed on the substrate 210. The light emitting device 211 may be, for example, a Light Emitting Diode (LED) or may be a mini LED or a micro LED. In addition, the light emitting devices 211 may be arranged in a form in which the chip-type light emitting devices 211 are mounted on the substrate 210, so that the thickness of the backlight unit 200 may be reduced and a light source having a wide radiation angle and high optical efficiency may also be provided. The light emitting device 211 configured to be mounted on the substrate 210 may be referred to as a light emitting device 211 having a flip chip structure.

The light emitting device 211 may emit light in a white wavelength band, or the light emitting device 211 may emit light in a specific wavelength band (e.g., a blue wavelength band) in some cases. The substrate 210 may be a printed circuit board, and a reflector 212 may be disposed on at least a portion of an area of the substrate 210 where the light emitting device 211 is not disposed. The light source protection unit 205 may be disposed on the plurality of light emitting devices 211 and the reflector 212. The light source protection unit 205 may protect the plurality of light emitting devices 211 and may provide a function of diffusing light emitted from the light emitting devices 211. The light source protecting unit 205 may be a resin layer containing resin.

A light-modifying sheet 216 may be disposed on the light source protecting unit 205. The light-modifying sheet 216 may include a plurality of light-modifying patterns 216p disposed on a face facing the light-emitting device 211. Here, the plurality of light modification patterns 216p may be disposed on the lower surface of the light modification sheet 216 at positions corresponding to the plurality of light emitting devices 211. The light modification pattern 216p may transmit a portion of light emitted from the light emitting device. The light-modifying sheet 216 may be a light-controlling sheet that is capable of transmitting a portion of light. The light-modifying sheet can scatter, reflect, diffract, or transmit light emitted from the light-emitting devices 211, thereby improving the image quality of the backlight unit 200.

That is, by arranging the light modification pattern 216p in a region where the intensity of light emitted from the light emitting devices 211 is highest, it is possible to reduce a luminance deviation between a region where the light emitting devices 211 are disposed (a region having a larger amount of light) and a region between the light emitting devices 211 (a region having a smaller amount of light).

The light-modifying sheet 216 may include a light-modifying material. In addition, the light modification pattern 216p may include titanium dioxide (TiO)₂)。Additionally, the light modifying material may be white. However, it is not limited thereto.

A diffusion plate 218 configured to diffuse light incident from below may be provided on the light modification sheet 216. In addition, a phosphor film 217 or one or more optical sheets 219 may be disposed on the diffusion plate 218. When light incident on the phosphor film 217 is blue light, the light passing through the phosphor film 217 may be converted into white light.

Referring to fig. 3A, a plurality of light emitting devices 211 may be disposed on a substrate 210. A reflective film coated on the substrate 210 may be provided. The coated reflective film may be formed of a white pigment. That is, a white pigment may be applied to the substrate 210.

Referring to fig. 3B, a reflector 212 may be disposed on at least a portion of an area other than an area on the substrate 210 where the light emitting device 211 is disposed.

The reflector 212 may be provided in a shape in which a region corresponding to the light emitting device 211 is an opening, and the reflector 212 may be provided on the substrate 210. The reflector 212 can reflect light emitted from the light emitting device 211 to the front surface (facing the display panel 100) of the backlight unit, thereby improving the optical efficiency of the backlight unit.

Here, when the light emitting device 211 is provided in the form of a chip, since the light emitting device 211 is small in size, the height of the reflector 212 may be greater than the height of the light emitting device 211.

Accordingly, light emitted in the lateral direction of the light emitting device 211 can be reflected by the side of the opening in the reflector 212 and can be emitted to the front surface of the backlight unit 200, thereby further improving the optical efficiency of the backlight unit 200.

Referring to fig. 3C, a light source protection unit 205 may be disposed on the plurality of light emitting devices 211 and the reflector 212. The light source protection unit 205 may include, for example, resin. When the light source protection unit 205 includes resin, the light source protection unit 205 may be provided by providing a partition at the outside of the substrate 210 or the outside of the region in which the plurality of light emitting devices 211 are provided and applying the resin to the inside of the partition. The light source protection unit 205 plays a role of protecting the plurality of light emitting devices 211 disposed on the substrate 210 and the light source protection unit 205 may provide a function of a light guide plate by diffusing light emitted from the light emitting devices 211. The light emitted from the light emitting device 211 may be more uniformly spread to the upper surface of the light source protection unit 205 by the light source protection unit 205. At this time, even if the reflector 212 modifies or adjusts the direction in which light propagates through the light source protection unit 205 or the like, the intensity of light emitted in the vertical direction of the light emitting device 211 may be high, and thus the uniformity of an image may be deteriorated.

According to the embodiment of the present disclosure, by providing the light modification pattern 216p having optical characteristics such as scattering, reflection, diffraction, and transmission at a position corresponding to the light emitting device 211 on the light source protection unit 205, it is possible to improve uniformity of an image while reducing the thickness of the backlight unit 200.

Referring to fig. 3D, a light modification sheet 216 may be disposed on the light source protection unit 205, and a plurality of light modification patterns 216p may be disposed on a lower surface of the light modification sheet 216. However, the present disclosure is not limited thereto, and a plurality of light modification patterns 216p may be disposed on the upper surface of the light modification sheet 216. Then, the light modification sheet 216 may be bonded to the light source protection unit 205 by one sheet of the adhesive film 215. The adhesive film 215 may be an OCA film. The light-modifying sheet 216 may be made of, for example, PET, etc., but is not limited thereto. Each of the plurality of light modification patterns 216p disposed on the lower surface or the upper surface of the light modification sheet 216 may be arranged to correspond to one of the plurality of light emitting devices 211 disposed on the substrate 210. For example, the light modification pattern 216p may be disposed to at least partially overlap the light emitting device 211 in consideration of light diffusion characteristics, and the light modification pattern 216p may be disposed to overlap a region including a region where the light emitting device 211 is disposed. The light modification pattern 216p may scatter, reflect, diffract, or transmit light emitted from the light emitting device 211. For example, the light-modifying pattern 216p may scatter light emitted from the light-emitting device 211 such that the light can be emitted from the light-modifying sheet 216. In addition, the light modification patterns 216p may reflect light emitted from the light emitting devices 211 in the vertical direction and may cause the light to be reflected again by the reflector 212, so that the light is emitted to the regions between the light emitting devices 211 or the regions between the light modification patterns 216 p.

As described above, the light emitted from the light emitting device 211 may be scattered, reflected, diffracted, or transmitted through the light modification pattern 216p, and the image quality of the backlight unit 200 may be improved.

Referring to fig. 3E, a diffusion plate 218 may be disposed on the light-modifying sheet 216, and a phosphor film 217 may be disposed on the diffusion plate 218. Then, at least one optical sheet 219 may be disposed on the phosphor film 217. Here, the positions where the diffusion plate 218 and the phosphor film 217 are disposed may be interchanged. The diffuser plate 218 may diffuse the light emitted through the light-modifying sheet 216.

The phosphor film 217 may include a phosphor having a specific color, and may excite incident light to emit light in a specific wavelength band. Accordingly, the light passing through the phosphor film 217 may have a specific color of the phosphor included in the phosphor film 217 or a color mixed with the specific color. For example, in the case where the light emitting device 211 emits light in a first wavelength band (e.g., blue light), the phosphor film 217 may emit light in a second wavelength band (e.g., green light) and light in a third wavelength band (e.g., red light) in response to light incident on the phosphor film 217.

In some cases, the phosphor film 217 may be disposed in a partial region on the diffusion plate 218. For example, when the light emitting device 211 emits light in a blue wavelength band, the phosphor film 217 may be disposed only in a region other than a region corresponding to a region where the blue sub-pixel SP is disposed in the liquid crystal panel 100. That is, light that does not pass through the phosphor film 217 may be caused to reach the blue sub-pixel SP of the liquid crystal panel 100. In addition, the phosphor film 217 may not be provided in the backlight unit 200. For example, in the case where the light emitting device 211 emits light in a white wavelength band or a color conversion film emitting light in a green wavelength band and light in a red wavelength band is coated on an emission surface thereof, the phosphor film 217 may not be provided.

As described above, the embodiment may improve the image quality of the backlight unit while reducing the thickness of the backlight unit by providing the light-modifying sheet 216 including the light-modifying pattern 216p, which is disposed at the position corresponding to the light-emitting device 211 and various optical elements.

Hereinafter, the embodiment will be described by specific examples of the light modification pattern 216p provided on the light modification sheet 216.

Referring to fig. 4, a substrate 210 may be disposed on the cover bottom 300 and the substrate 210 may be joined to the cover bottom 300 by an adhesive tape 210a disposed between the cover bottom 300 and the substrate 210.

A plurality of light emitting devices 211 may be disposed on the substrate 210, and a reflector 212 may be disposed on at least a portion of an area other than the area on the substrate 210 where the light emitting devices 211 are disposed.

Here, each of the light emitting devices 211 may be, for example, an LED and may include a light emitting portion 211a, the light emitting portion 203a including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer, and an electrode portion 211 b. A light source protection unit 205 is disposed on the plurality of light emitting devices 211 and the reflector 212. A light modification sheet 216 may be disposed on the light source protection unit 205, and a light modification pattern 216p may be disposed on the light modification sheet 216 at a position corresponding to the light emitting device 211. Then, a diffusion plate 218, a phosphor film 217, an optical sheet 219, and the like may be disposed on the light modification sheet 216.

The light-modifying pattern 216p provided on the lower surface of the light-modifying sheet 216 may be realized by printing a substance having light-modifying properties on the light-modifying sheet 216. For example, the light-modifying pattern 216p may be formed by printing a pattern comprising titanium dioxide (TiO) on the light-modifying sheet 216₂) The method of (2). In addition, the light modification patterns 216p disposed on the lower surface of the light modification sheet 216 may be arranged in one layer or may be arranged in a multi-layer structure. That is, as shown in fig. 4, the light modification patterns 216p disposed on the lower surface of the light modification sheet 216 may be configured as three layers. By printing light on the light-modifying sheet 216The method of modifying the substance three times to achieve the light modifying pattern 216p, and the area to be printed with the light modifying substance may be tapered. Then, the light modification pattern 216p may be disposed on the light emitting device 211 by inverting the light modification sheet 216 on which the light modification pattern 216p is disposed and disposing the light modification sheet 216 on the light source protection unit 205.

Accordingly, the region of the light-modifying pattern 216p may be tapered away from the bottom of the light-modifying sheet 216, and the thickness of the central portion of each light-modifying pattern 216p may be greater than the thickness of the outer (peripheral) portion thereof.

That is, since the intensity of light emitted from the light emitting device 211 in the vertical direction is greater than the intensity of light emitted in the oblique direction or the lateral direction, the central portion of the light modification pattern 216p may be configured to be thicker than other portions. However, the embodiment is not limited thereto.

By providing the light modification pattern 216p on the light emitting device 211 as described above, it is possible to prevent or mitigate the occurrence of hot spots in the region where the light emitting device 211 is provided by scattering, reflecting, diffracting or blocking at least a part of the light emitted from the light emitting device 211 in the vertical direction. The light modification sheet 216 on which the light modification pattern 216p is disposed may be bonded to the light source protection unit 205 via an adhesive film 215. At this time, the adhesive film 215 may be disposed in at least a portion of the region other than the region where the light modification pattern 216p is disposed on the lower surface of the light modification sheet 216.

Accordingly, the adhesive film 215 may not be disposed in the region where the light modification pattern 216p is disposed, and an air gap may exist between the light modification pattern 216p and the light source protection unit 205. In addition, the side of the light modification pattern 216p and the side of the adhesive film 215 may be spaced apart from each other. Since there is an air gap between the light modification pattern 216p and the light source protection unit 205, light emitted in a lateral direction of the light modification pattern 216p may be reflected by the air gap, pass through the light modification sheet 216, and toward the display panel 100. That is, light emitted in the lateral direction of the light modification pattern 216p may be emitted at a large refraction angle by an air gap having a low refractive index or may be reflected by the air gap. Since the light reflected by the air gap is emitted after being reflected again by the reflector 212, the optical efficiency may be improved while assisting the light modification function of the light modification pattern 216 p.

As described above, by the structure in which the light modification pattern 216p and the air gap are disposed at the position corresponding to the light emitting device 211, the optical efficiency of the backlight unit may be improved while preventing or alleviating the hot spot. In addition, the light modification patterns 216p disposed on the lower surface of the light modification sheet 216 may be arranged in different structures depending on the position where the light modification patterns 216p are disposed.

Referring to fig. 5A, an example of luminance occurring through the backlight unit according to the structure of the light modification pattern 216p is illustrated, where EX1 illustrates an example of luminance measured when the light modification pattern 216p is arranged in a constant structure, and EX2 denotes an example of luminance measured when the light modification pattern 216p is arranged in a different structure depending on the position of the light modification pattern 216 p.

As shown by EX1 in fig. 5A, when the structure of the light modification pattern 216pa disposed in the outer region of the backlight unit 200 and the structure of the light modification pattern 216pd disposed in the central region are the same (e.g., the same thickness or size), the luminance of the outer (peripheral) region of the backlight unit may be lower than the luminance of the central region of the backlight unit.

That is, since the number of the light emitting devices 211 providing light to the corresponding regions is relatively small compared to the central region when the light modification patterns 216p having the same level of light modification characteristics are disposed in the outer region of the backlight unit, the luminance in the outer region of the backlight unit may be reduced compared to the central region of the backlight unit.

Accordingly, as shown by EX2 in fig. 5A, by arranging the light modification patterns 216pa disposed in the outer region of the backlight unit 200 and the light modification patterns 216pd disposed in the central region of the backlight unit 200 to have different structures, it is possible to prevent luminance degradation of the outer region of the backlight unit 200 and make the overall luminance more uniform.

As an example, the light modification pattern 216p may be arranged such that a thickness T1 of the light modification pattern 216pa disposed in the outer region of the backlight unit 200 is less than a thickness T2 of the light modification pattern 216pd disposed in the central region.

Alternatively, the light modification patterns 216p may be arranged such that a region W1 of the thickest part in the light modification patterns 216pb disposed adjacent to the outer region of the backlight unit is smaller than a region W2 of the thickest part in the light modification patterns 216 pd. That is, of the light modification patterns 216pa and 216pb disposed in the outer region of the backlight unit 200 or disposed in the region adjacent to the outer region, the region of the portion having the higher blocking characteristic is made smaller.

In addition, the light modification pattern 216p may be arranged such that the thickness of the light modification pattern 216p gradually decreases from the central region of the backlight unit 200 toward the outer region of the backlight unit 200, or such that the region of the thickest portion of the light modification pattern 216p gradually decreases. That is, in the light modification patterns 216pa and 216pb disposed in the outer region of the backlight unit 200 or disposed adjacent to the outer region of the backlight unit 200, the region of the portion having the high blocking characteristic is made small.

In addition, the thickness of the light modification pattern 216p gradually decreases from the central region of the backlight unit 200 to the outer region of the backlight unit 200, or the region of the thickest portion of the light modification pattern 216p gradually decreases from the central region of the backlight unit 200 to the outer region of the backlight unit 200.

In addition, in some cases, the light modification patterns 216p may be differently arranged such that the number or interval of the light emitting devices 211 is different between the central region and the outer region of the backlight unit 200.

Referring to fig. 5B, another example of a structure in which a light modification pattern 216p is provided on a lower surface of a light modification sheet 216 is illustrated.

Here, the distance between the light emitting devices 211 disposed in the outer region of the backlight unit 200 may be smaller than the distance between the light emitting devices 211 disposed in the central region of the backlight unit 200. That is, the light emitting devices 211 may be arranged in the following structure so that the luminance becomes uniform in the central region and the outer region of the backlight unit 200: in this structure, the light emitting devices 211 are more densely disposed in the outer region of the backlight unit 200.

In addition, since the light modification patterns 216p disposed on the lower surface of the light modification sheet 216 are arranged to correspond to the light emitting devices 211, the intervals between the light modification patterns 216p disposed in the outer region of the backlight unit 200 may be different from the intervals between the light modification patterns 216p disposed in the central region of the backlight unit 200.

As an example, the interval D1 in the first direction of the light modification patterns 216p disposed in the outer region of the backlight unit 200 may be smaller than the interval D2 in the first direction of the light modification patterns 216p disposed in the central region of the backlight unit 200. In addition, the interval D3 in the second direction of the light modification patterns 216p disposed in the outer region of the backlight unit 200 may be smaller than the interval D4 in the second direction of the light modification patterns 216p disposed in the central region of the backlight unit 200.

The size, thickness, etc. of the light modification patterns 216p disposed in the outer region of the backlight unit 200 may be different from the size, thickness, etc. of the light modification patterns 216p disposed in the central region of the backlight unit 200.

For example, as shown in fig. 5B, the size S1 of the light modification patterns 216pe and 216pf disposed in the outer region of the backlight unit 200 may be smaller than the size S2 of the light modification pattern 216pg disposed in the central region of the backlight unit 200.

Alternatively, the light modification pattern 216p may have a multi-layered structure as described above. In this case, the thicknesses of the light modification patterns 216pe and 216pf disposed in the outer region of the backlight unit 200 or the regions of the portions having the maximum thicknesses of the light modification patterns 216pe and 216pf, respectively, may be less than the thickness of the light modification pattern 216pg disposed in the central region of the backlight unit 200 or the regions of the portions having the maximum thicknesses of the light modification pattern 216 pg.

That is, by reducing the size of the light modification patterns 216pe and 216pf disposed in the outer region of the backlight unit 200, the light modification patterns 216pe and 216pf may be disposed to correspond to the light emitting devices 211 arranged at small intervals. Accordingly, it is possible to prevent or mitigate the generation of hot spots at positions corresponding to the light emitting devices 211 in the outer region of the backlight unit 200.

In addition, by reducing the level at which light emitted from the light emitting device 211 is scattered, reflected, diffracted, or blocked in the outer region of the backlight unit 200, the amount of light to be emitted is increased and the luminance of the outer region of the backlight unit 200 is improved. Accordingly, the entire area of the backlight unit 200 may be made to exhibit more uniform luminance.

As described above, by arranging the light modification patterns 216p to have different structures in different regions in the backlight unit 200, it is possible to prevent or reduce luminance from being reduced in an outer region of the backlight unit 200 and to improve uniformity of luminance.

In addition, by the structure in which the above-described modification pattern 216p is disposed, it is possible to prevent or reduce hot spots of the backlight unit 200 and to improve uniformity of luminance.

The embodiment can also provide a method of improving the image quality of the backlight unit 200 while increasing the optical efficiency of the backlight unit by diffracting light emitted in the vertical direction of the light emitting devices 211.

Fig. 6 is a structural view illustrating an embodiment of the backlight unit shown in fig. 1, and fig. 7 is a perspective view illustrating a reflector employed in the backlight unit shown in fig. 1.

Referring to fig. 6 and 7, the backlight unit 200a may include: a substrate 210; a light emitting device 211 disposed on the substrate 210, the light emitting device 211 having a flip chip structure; a reflector 212 disposed so as to surround the light emitting device 211 and a first area 1AR including the periphery of the light emitting device; a colored resin 213 provided in the first region 1 AR; an adhesive film 215 disposed above the colored resin 213 to be spaced apart from the colored resin 213 by a predetermined distance; and a light-modifying sheet 216 disposed on the adhesive film 215 and having a light-modifying pattern 216p disposed to correspond to a position of the light-emitting device 211.

The light emitting device 211 may have a flip chip structure. The light emitting device 211 may emit blue light. However, the color of light emitted by the light emitting device 211 is not limited thereto. The light emitting device 211 may be disposed at the center of the first area 1AR on the substrate 210.

The reflector 212 may reflect light emitted from the light emitting device 211. The reflector 212 may be disposed on the substrate 210. The reflector 212 may include an aperture corresponding to the first area 1AR, as shown in fig. 7. When the reflector 212 is disposed on the substrate 210, the first area 1AR on the substrate 210 may be exposed to correspond to the hole. In addition, the substrate 210 may reflect light. The substrate 210 may include a reflective material. The substrate 210 and the reflector 212 may be coated with a white pigment to reflect light. The white pigment may include a Photo Solder Resist (PSR). However, the present disclosure is not limited thereto. Here, the shape of the hole corresponding to the first area 1AR is shown as a circle, but is not limited thereto.

The colored resin 213 may be provided in the first region 1 AR. Due to the holes, the colored resin 213 may be provided only in the first region 1 AR. The colored resin 213 may be cured by ultraviolet rays. After the colored resin 213 is disposed in the first area 1AR, the colored resin 213 may be cured using ultraviolet rays. The colored resin 213 may include a red phosphor. The light passing through the colored resin 213 may be purple. However, the present disclosure is not limited thereto. Since the colored resin 213 is provided only in the first area 1AR, the amount of phosphor used can be reduced, thereby reducing the manufacturing cost.

The adhesive film 215 may be disposed on the colored resin 213. The adhesive film 215 may contain a resin. The refractive index of the adhesive film 215 may be the same as or similar to that of the colored resin 213. However, the present disclosure is not limited thereto. The adhesive film 215 may be disposed to be spaced apart from the colored resin 213 by a predetermined distance. That is, the optical path modulator 214 having a refractive index different from that of the colored resin 213 may be provided between the adhesive film 215 and the colored resin 213. The optical path modulator 214 may be any suitable material having a refractive index different from that of the colored resin 213. The light path modulator 214 and the colored resin 213 may contact each other so that light may undergo total internal reflection at the boundary between the light path modulator 214 and the colored resin 213. The angle at which the light is totally reflected may correspond to the difference in refractive index between the optical path modulator 214 and the colored resin 213. The optical path modulator 214 may be a material having a refractive index ranging from 1 to 1.46. The optical path modulator 214 may be air. However, the present disclosure is not limited thereto.

The light-modifying sheet 216 may include a light-modifying pattern 216 p. The light modification sheet 216 may be disposed on the adhesive film 215 such that the light modification pattern 216p is disposed at a position corresponding to the light emitting device 211. The generation of hot spots may be prevented or mitigated by scattering, reflecting, diffracting or blocking light emitted from the light emitting device in the vertical direction by the light modification pattern 216 p. The light modification pattern 216p may reflect incident light.

A phosphor film 217 may be disposed on the light-modifying sheet 216. The color of the phosphor included in the phosphor film 217 may be different from the color of the phosphor included in the colored resin 213. A diffusion plate 218 may be disposed on the phosphor film 217, and an optical sheet 219 may be disposed on the diffusion plate 218. The number of the optical sheets 219 is shown as one, but is not limited thereto.

In an embodiment, a reflector 212a may also be disposed over the light emitting device 211. The reflector 212a disposed above the light emitting device 211 may be a distributed bragg reflector. However, the present disclosure is not limited thereto. Light emitted from the light emitting device 211 and having a path in a vertical direction or in a direction close to the vertical direction may be reflected by the reflector 212 a.

Referring to fig. 8, the light emitting device 211 may be disposed in a colored resin 213. Accordingly, when light emitted from the light emitting device 211 passes through the colored resin 213, the light emitted from the light emitting device 211 may be excited to have energy corresponding to a color of a color in which the phosphor included in the colored resin 213 is mixed. For example, when the light emitting device 211 emits blue light and the colored resin 213 includes a red phosphor, the light passing through the colored resin 213 may have a violet color. However, depending on the path of the light, there may be a difference in the degree of color mixing. For example, since the thickness of the colored resin 213 through which the light beams of the first group a among the light beams emitted from the light emitting device 211 pass is small, the colors cannot be sufficiently mixed. However, among the light beams emitted from the light emitting device 211, the light beam corresponding to the second group B passes through the colored resin 213 and is reflected by the reflector 212. Then, the light beam passes through the colored resin 213 again and then travels toward the display panel 100. Therefore, the light beams of the first group a and the light beams of the second group B may differ in color reproducibility. In addition, there arises a problem in that the color reproducibility of the backlight unit 200a is deteriorated by the light beams of the first group a.

In order to solve the above-described problem, when at least some of the light beams of the first group a undergo total internal reflection at the boundary of the colored resin 213 so that the path thereof is changed, the light beams emitted from the light emitting devices 211 may be included in the third group C. The light beams of the third group C are reflected at the upper boundary of the colored resin 213, then directed to the colored resin 213 toward the reflector 212 (or the substrate 210), and then reflected by the reflector 212 (or the substrate 210) to be radiated toward the display panel 100. This may enhance the color reproducibility of the backlight unit 200 a.

In order for total internal reflection to occur at the boundary of the colored resin 213, a material having a refractive index different from that of the colored resin 213 (for example, an optical path modulator 214 shown in fig. 6) may be provided on the colored resin 213. In addition, the angle θ 1 at which total internal reflection occurs at the boundary of the colored resin 213 can also be increased by providing a large difference in refractive index between the colored resin 213 and the material provided on the colored resin 213, which makes it possible to increase the amount of light that undergoes total internal reflection at the boundary of the colored resin 213.

As shown in fig. 9A, in the backlight unit 200a, a light emitting device 211 may be disposed on a substrate 210. Each light emitting device 211 may have a flip chip structure directly connected to the substrate 210. The light emitting device 211 may be arranged to correspond to the first area 1AR on the substrate 210. Each light emitting device 211 may be disposed at the center of one of the first areas 1 AR. Here, although the number of the light emitting devices 211 disposed on the substrate 210 is illustrated as three, the present disclosure is not limited thereto. The substrate 210 may include a reflective material to reflect light. In addition, the substrate 210 may be coated with a white pigment. In addition, each light emitting device 211 may be further provided with a reflector 212a on the light emitting device 211, as shown in fig. 6. The reflector 212a disposed on the light emitting device 211 may be a distributed bragg reflector.

As shown in fig. 9B, a reflector 212 may be disposed on the substrate 210. The reflector 212 may include a hole having a predetermined diameter, and the hole may correspond to the first area 1 AR. Therefore, the first area 1AR on the substrate 210 may not be covered by the reflector 212.

In addition, as shown in fig. 9C, the colored resin 213 is put into the first area 1AR corresponding to the hole of the reflector 212, and the colored resin 213 is cured by ultraviolet rays. The upper surface of the colored resin 213 may be disposed below the upper surface of the reflector 212. That is, the height h2 of the reflector 212 may be higher than the height h1 of the colored resin 213. Here, although the upper surface of the colored resin 213 is shown to be parallel to the horizontal plane, the present disclosure is not limited thereto, and the upper surface of the colored resin 213 may be concave or convex. However, the highest point of the upper surface of the colored resin 213 is lower than the height of the reflector 212.

Then, as shown in fig. 9D, an adhesive film 215 may be disposed over the substrate 210 on which the reflector 212 is disposed. Since the height of the reflector 212 is higher than the height of the colored resin 213, the adhesive film 215 may be disposed such that the adhesive film 215 is disposed above the colored resin 213 to form a predetermined gap above the colored resin 213. The optical path modulator 214 may be disposed in a predetermined gap. The optical path modulator 214 may be air. However, the optical path modulator 214 is not limited thereto, and may be any material as long as the material has a refractive index different from that of the colored resin 213. The adhesive film 215 may be a light-transmitting material.

In addition, as shown in fig. 9E, a light modification sheet 216 may be disposed on the adhesive film 215. The light-modifying sheet 216 may include a light-modifying pattern 216p, and the light-modifying pattern 216p may be disposed at a position corresponding to a position where the light-emitting device 211 is disposed. The light modification pattern 216p included in the light modification sheet 216 can reflect, scatter, diffract, or block light emitted from the light emitting devices 211 in the vertical direction or light emitted from the light emitting devices 211 at an angle close to the vertical direction, thereby preventing or mitigating the generation of hot spots in the backlight unit 200 shown in fig. 1.

In addition, as shown in fig. 9F, a phosphor film 217 may be disposed on the light modification sheet 216. The phosphor film 217 may include a phosphor having a color different from that of the colored resin. A diffusion plate 218 may be disposed on the phosphor film 217, and an optical sheet 219 may be disposed on the diffusion plate 218.

Referring to fig. 10, the backlight unit 200b may include: a substrate 210; a light emitting device 211 disposed on the substrate 210, the light emitting device 211 having a flip chip structure; a reflector 212 disposed so as to surround the light emitting device 211 and a first area 1AR including the periphery of the light emitting device; a colored resin 213 provided in the first region 1 AR; an adhesive film 215 disposed to be spaced apart from the colored resin 213 by a predetermined distance; and a light-modifying sheet 216 disposed on the adhesive film 215, the light-modifying sheet 216 having a light-modifying pattern 216p disposed to correspond to a position of the light-emitting device 211.

The light emitting device 211 may emit blue light. However, the present disclosure is not limited thereto. The light emitting device 211 may be disposed at the center of the first area 1AR on the substrate 210.

The reflector 212 may reflect light emitted from the light emitting device 211. The reflector 212 may be disposed on the substrate 210. The reflector 212 may be the same as the reflector 212 shown in fig. 3, and may include an aperture corresponding to the first area 1 AR. When the reflector 212 is disposed on the substrate 210, the first area 1AR on the substrate 210 may be exposed to correspond to the hole. The reflector 212 may be coated with a white pigment to reflect light. The white pigment may include a Photo Solder Resist (PSR). However, the present disclosure is not limited thereto. Here, the shape of the hole corresponding to the first area 1AR is shown as a circle, but is not limited thereto.

The colored resin 213 may be provided in the first region 1 AR. Due to the holes, the colored resin 213 may be provided only in the first region 1AR (and in other regions exposed through other holes formed by the reflector 212). The colored resin 213 may be cured by ultraviolet rays. After the colored resin 213 is disposed in the first area 1AR, the colored resin 213 may be cured using ultraviolet rays. The colored resin 213 may include a yellow phosphor. In addition, the colored resin 213 may include a red phosphor and a green phosphor. The light passing through the colored resin 213 may be purple. However, the present disclosure is not limited thereto. Since the colored resin 213 is provided only in the first area 1AR (not in a large area on the substrate 210), the amount of phosphor used can be reduced, thereby reducing the manufacturing cost.

The adhesive film 215 may be disposed on the colored resin 213. The adhesive film 215 may contain a resin. The refractive index of the adhesive film 215 may be the same as or similar to that of the colored resin 213. However, the present disclosure is not limited thereto. The adhesive film 215 may be an OCA film. The adhesive film 215 may be disposed to be spaced apart from the colored resin 213 by a predetermined distance. That is, the optical path modulator 214 having a refractive index different from that of the colored resin 213 may be provided between the adhesive film 215 and the colored resin 213. The light path modulator 214 and the colored resin 213 may contact each other so that light may undergo total internal reflection at the boundary between the light path modulator 214 and the colored resin 213. The angle at which the light undergoes total internal reflection may correspond to the difference in refractive index between the optical path modulator 214 and the colored resin 213. The optical path modulator 214 may be air. However, the present disclosure is not limited thereto.

The light-modifying sheet 216 may include a light-modifying pattern 216 p. The light modification sheet 216 may be disposed on the adhesive film 215 such that the light modification pattern 216p is disposed at a position corresponding to the light emitting device 211. The generation of hot spots in the backlight unit 200b may be prevented or mitigated by reflecting, scattering, diffracting or blocking light emitted from the light emitting devices and having a path in the vertical direction or a path close to the vertical direction by the light modification pattern 216 p. The light modification pattern 216p may have the same shape as the light modification pattern shown in fig. 4.

A diffusion plate 218 may be provided on the light modification sheet 216, and an optical sheet 219 may be provided on the diffusion plate 218. The number of the optical sheets 219 is shown as one, but is not limited thereto.

Therefore, unlike the backlight unit shown in fig. 2, the colored resin 213 may include two phosphors having different colors or may include phosphors having two colors, so that the backlight unit may not include the phosphor film 217 over the light-modifying sheet. This makes it possible to reduce the amount of phosphor used in the backlight unit 200, thereby reducing the manufacturing cost.

Referring to fig. 11, the backlight unit 200c may include: a substrate 210; a light emitting device 211 having a flip chip structure disposed on the substrate 210; a reflector 212 disposed so as to surround the light emitting device 211 and a first area 1AR including the periphery of the light emitting device; a colored resin 213 provided in the first region 1 AR; an adhesive film 215 disposed above the colored resin 213 to be spaced apart from the colored resin 213 by a predetermined distance; and a light-modifying sheet 216 disposed on the adhesive film 215, the light-modifying sheet 216 having a light-modifying pattern 216p disposed to correspond to a position of the light-emitting device 211.

The light emitting device 211 may have a flip chip structure. In the flip chip structure, the light emitting device 211 is directly disposed on the substrate 210 instead of being mounted in a package, thereby making it possible to manufacture a light source that is light in weight and has a large radiation angle. The light emitting device 211 may emit blue light. However, the present disclosure is not limited thereto. The light emitting device 211 may be disposed at the center of the first area 1AR on the substrate 210.

A groove CA corresponding to the first area 1AR may be provided in the substrate 210. The light emitting device 211 may be disposed in the groove CA. The outer wall of the groove CA may act as a reflector. In order for the outer wall of the groove CA to function as a reflector, white pigment may be applied to the substrate 210. That is, the reflector may include a substrate 210 and a white pigment applied to the substrate. The white pigment may comprise a Photo Solder Resist (PSR). However, the present disclosure is not limited thereto. Here, the shape of the groove CA corresponding to the first area 1AR may be a circle, but is not limited thereto.

The colored resin 213 may be provided in the first region 1 AR. Due to the grooves CA, the colored resin 213 may be provided only in the first region 1AR (and in other regions exposed through other grooves of the substrate 210). The colored resin 213 may be cured by ultraviolet rays. After the colored resin 213 is disposed in the first area 1AR, the colored resin 213 may be cured using ultraviolet rays. The colored resin 213 may include a red phosphor. However, the colored resin 213 is not limited thereto and the colored resin 213 may include a yellow phosphor. In addition, the colored resin 213 may include a red phosphor and a green phosphor. The light passing through the colored resin 213 may be purple. However, the present disclosure is not limited thereto. Since the colored resin 213 is provided only in the first area 1AR, the amount of use of the phosphor can be reduced.

The adhesive film 215 may be disposed on the colored resin 213. The adhesive film 215 may contain a resin. The refractive index of the adhesive film 215 may be the same as or similar to that of the colored resin 213. However, the present disclosure is not limited thereto. The adhesive film 215 may be an OCA film. The adhesive film 215 may be disposed to be spaced apart from the colored resin 213 by a predetermined distance. That is, the optical path modulator 214 having a refractive index different from that of the colored resin 213 may be provided between the adhesive film 215 and the colored resin 213. The light path modulator 214 and the colored resin 213 may contact each other so that light may undergo total internal reflection at the boundary between the light path modulator 214 and the colored resin 213. The angle at which the light undergoes total internal reflection may correspond to the difference in refractive index between the optical path modulator 214 and the colored resin 213. The optical path modulator 214 may be a material having a refractive index ranging from 1 to 1.46. The optical path modulator may be air. However, the present disclosure is not limited thereto.

The light-modifying sheet 216 may include a light-modifying pattern 216 p. The light modification sheet 216 may be disposed on the adhesive film 215 such that the light modification pattern 216p is disposed at a position corresponding to the light emitting device 211. The generation of hot spots in the backlight unit 200c may be prevented or mitigated by reflecting, scattering, diffracting or blocking light emitted from the light emitting devices and having a path in the vertical direction or a path close to the vertical direction by the light modification pattern 216 p. The light modification pattern 216p may have the same shape as the light modification pattern shown in fig. 4. However, the present disclosure is not limited thereto.

A phosphor film 217 may be disposed on the light-modifying sheet 216. The phosphor film 217 may include a green phosphor. However, the present disclosure is not limited thereto. In addition, when the color resin 213 includes a yellow phosphor or a red phosphor and a green phosphor, the phosphor film 217 may not be disposed on the light-modifying sheet 216.

A diffusion plate 218 may be disposed on the light-modifying sheet 216 or the phosphor film 217, and an optical sheet 219 may be disposed on the diffusion plate 218. The number of the optical sheets 219 is shown as one, but is not limited thereto.

The above description and drawings provide examples of the technical idea of the present disclosure for illustrative purposes only. Those skilled in the art to which the present disclosure pertains will appreciate that various modifications and changes may be made in the form of, for example, combinations, divisions, substitutions and changes of configurations without departing from the essential characteristics of the present disclosure. Therefore, the embodiments disclosed in the present disclosure are intended to illustrate the scope of the technical idea of the present disclosure, and the scope of the present disclosure is not limited by the embodiments. The scope of the present disclosure should be construed in the following manner based on the appended claims: all technical concepts that are included within the scope equivalent to the claims belong to the present disclosure.

Furthermore, embodiments of the present disclosure further include:

embodiment (1) a backlight unit, comprising:

a substrate;

a light emitting device on the substrate;

a lower reflector on the substrate, the lower reflector having an aperture to receive and expose the light emitting device, the lower reflector having a height greater than a height of the light emitting device and configured to reflect light emitted from the light emitting device;

a colored resin in the hole and on the light emitting device, the colored resin having a height lower than a height of the lower reflector; and

an optical path modulator above the light emitting device and on the colored resin, the optical path modulator having a different refractive index compared to a refractive index of the colored resin to reflect the emitted light toward the lower reflector at a boundary of the optical path modulator and the colored resin.

Embodiment (2) the backlight unit according to embodiment (1), wherein the colored resin includes a plurality of phosphors having at least two different colors.

Embodiment (3) the backlight unit according to embodiment (1), wherein the colored resin has an upper surface that is concave or convex.

Embodiment (4) the backlight unit according to embodiment (1), wherein the optical path modulator includes air.

Embodiment (5) the backlight unit according to embodiment (1), further comprising:

a distributed Bragg reflector on the light emitting device in the aperture and between the substrate and the optical path modulator.

Embodiment (6) the backlight unit according to embodiment (1), further comprising:

an adhesive film on the lower reflector and the optical path modulator; and

a light-modifying sheet on the adhesive film, the light-modifying sheet comprising a plurality of light-modifying patterns at least partially overlapping a plurality of light-emitting devices, the plurality of light-modifying patterns having one or more layers comprising a top layer on a surface of the light-modifying sheet facing the substrate, there being an air gap between the one or more layers and the adhesive film.

Embodiment (7) the backlight unit according to embodiment (1), further comprising:

an adhesive film on the lower reflector and the optical path modulator; and

a light-modifying sheet on the adhesive film, the light-modifying sheet comprising a plurality of light-modifying patterns, at least one of the plurality of light-modifying patterns at least partially overlapping the light-emitting device and having one or more layers comprising a top layer on a surface of the light-modifying sheet facing the substrate, there being an air gap between the one or more layers and the adhesive film.

Embodiment (8) the backlight unit of embodiment (6), wherein the one or more layers further comprise:

an intermediate layer on a surface of the top layer facing the substrate, the top layer having a size larger than a size of the intermediate layer.

Embodiment (9) the backlight unit of embodiment (8), wherein the one or more layers further comprise:

an underlayer on a surface of the intermediate layer facing the substrate, the underlayer having a size smaller than that of the intermediate layer.

Embodiment (10) the backlight unit according to embodiment (6), wherein a central portion of at least one of the plurality of light modification patterns is configured to be thicker than other portions.

Embodiment (11) the backlight unit according to embodiment (6), further comprising:

a phosphor film on the light-modifying sheet;

a diffusion plate on the phosphor film; and

an optical sheet on the diffusion plate.

Embodiment (12) a backlight unit, comprising:

a substrate comprising a trough having sidewalls coated with a reflective material and having a first height;

a light emitting device in the slot, the light emitting device having a second height that is lower than the first height;

a colored resin in the trough and on the light emitting device, the colored resin having a third height that is lower than the first height; and

an optical path modulator in the groove and on the colored resin, the optical path modulator having a refractive index different from a refractive index of the colored resin to reflect light emitted from the light emitting device toward the sidewall of the groove at a boundary of the optical path modulator and the colored resin.

Embodiment (13) the backlight unit according to embodiment (12), wherein the colored resin includes a plurality of phosphors having at least two different colors.

Embodiment (14) the backlight unit according to embodiment (12), wherein the colored resin has an upper surface that is concave or convex.

Embodiment (15) the backlight unit according to embodiment (12), wherein the optical path modulator includes air.

Embodiment (16) the backlight unit according to embodiment (12), further comprising:

a distributed Bragg reflector on the light emitting device in the slot and between the substrate and the optical path modulator.

Embodiment (17) a method for manufacturing a backlight unit, the method comprising:

disposing a plurality of light emitting devices in a region of a substrate;

disposing a lower reflector on the substrate, wherein an aperture of the lower reflector receives and exposes the plurality of light emitting devices, the aperture having a depth greater than a height of the plurality of light emitting devices;

curing the colored resin in the holes, the cured resin having a height less than the depth; and

an optical path modulator having a refractive index different from that of the colored resin is provided in the hole and on the colored resin.

Embodiment (18) the method of embodiment (17), further comprising:

disposing a reflector on the plurality of light emitting devices; and

coating the substrate with a reflective material.

Embodiment (19) the method of embodiment (17), further comprising:

disposing an adhesive film on the lower reflector and the optical path modulator; and

disposing a light-modifying sheet on the adhesive film, the light-modifying sheet including a plurality of light-modifying patterns at least partially overlapping the plurality of light-emitting devices, respectively, the plurality of light-modifying patterns having one or more layers including a top layer on a surface of the light-modifying sheet facing the substrate, there being an air gap between the one or more layers and the adhesive film.

Embodiment (20) the method according to embodiment (17), further comprising:

disposing a light-modifying sheet on the adhesive film, the light-modifying sheet including a plurality of light-modifying patterns respectively at least partially overlapping the plurality of light-emitting devices, at least one of the plurality of light-modifying patterns having one or more layers including a top layer on a surface of the light-modifying sheet facing the substrate, there being an air gap between the one or more layers and the adhesive film.

Embodiment (21) the method of embodiment (19), further comprising:

printing the top layer on the surface of the light-modifying sheet.

Embodiment (22) the method according to embodiment (21), further comprising:

printing an intermediate layer of the one or more layers on the top layer, the top layer having an area larger than an area of the intermediate layer, wherein the light-modifying sheet with the printed top layer and intermediate layer is inverted before disposing the light-modifying sheet on the adhesive film.

Embodiment (23) the method of embodiment (22), further comprising:

printing a bottom layer of the one or more layers on the middle layer, the bottom layer having an area smaller than an area of the middle layer.

Embodiment (24) a backlight unit, comprising:

a light emitting device having a flip chip structure;

a first reflector disposed to surround a first region including the light emitting device and a periphery of the light emitting device;

a colored resin disposed in the first region;

an adhesive film disposed over the colored resin to be spaced apart from the colored resin by a predetermined distance; and

a light-modifying sheet disposed on the adhesive film, the light-modifying sheet including a light-modifying pattern disposed to correspond to a location of the light-emitting device.

Embodiment (25) the backlight unit according to embodiment (24), further comprising:

a material disposed between the adhesive film and the colored resin, the material having a refractive index different from a refractive index of the colored resin.

Embodiment (26) the backlight unit of embodiment (24), wherein the first reflector has a height higher than a height of the colored resin.

Embodiment (27) the backlight unit according to embodiment (24), further comprising: a substrate including a groove corresponding to the first region, and wherein a reflective film is applied to the substrate.

Embodiment (28) the backlight unit according to embodiment (24), further comprising:

a phosphor film disposed over the light-modifying sheet, the phosphor film including a phosphor having a color different from a color of the colored resin.

Embodiment (29) the backlight unit according to embodiment (24), wherein the colored resin includes two types of phosphors having different colors.

Embodiment (30) the backlight unit according to embodiment (24), further comprising:

a second reflector disposed on an upper surface of the light emitting device.

Embodiment (31) the backlight unit of embodiment (24), wherein the thickness of the light modification pattern gradually decreases from a central region of the backlight unit to an outer region of the backlight unit.

Embodiment (32) the backlight unit of embodiment (24), wherein the light-modifying pattern is configured to have different structures in different regions in the backlight unit.

Embodiment (33) a display device, comprising:

a display panel;

a backlight unit disposed below the display panel, the backlight unit configured to radiate light to the display panel;

wherein the backlight unit includes:

a light emitting device having a flip chip structure;

a colored resin disposed in the first region;

Embodiment (34) the display device according to embodiment (33), further comprising:

Embodiment (35) the display device according to embodiment (33), wherein the first reflector has a height higher than a height of the colored resin.

Embodiment (36) the display device according to embodiment (33), wherein the backlight unit further includes: a substrate including a groove corresponding to the first region, and wherein a reflective film is applied to the substrate.

Embodiment (37) the display device according to embodiment (33), further comprising:

Embodiment (38) the display device according to embodiment (33), wherein the colored resin includes two types of phosphors having different colors.

Embodiment (39) the display device according to embodiment (33), further comprising:

a second reflector disposed on an upper surface of the light emitting device.

Claims

1. A backlight unit, comprising:

a substrate;

a light emitting device on the substrate;

2. The backlight unit according to claim 1, wherein the colored resin comprises a plurality of phosphors having at least two different colors.

3. The backlight unit according to claim 1, wherein the colored resin has an upper surface that is concave or convex.

4. The backlight unit according to claim 1, wherein the optical path modulator comprises air.

5. The backlight unit according to claim 1, further comprising:

6. The backlight unit according to claim 1, further comprising:

an adhesive film on the lower reflector and the optical path modulator; and

7. The backlight unit according to claim 1, further comprising:

an adhesive film on the lower reflector and the optical path modulator; and

8. The backlight unit of claim 6, wherein the one or more layers further comprise:

9. The backlight unit of claim 8, wherein the one or more layers further comprise:

10. The backlight unit according to claim 6, wherein a central portion of at least one of the plurality of light modification patterns is configured to be thicker than other portions.