KR20200071651A - Back light unit and diplay including the same - Google Patents

Abstract

According to embodiments of the present invention, provided is a backlight unit which can reduce manufacturing costs and a display device including the same. The backlight unit comprises: a light emitting element having a flip chip structure; a first reflector disposed in a shape of surrounding a first region including the light emitting element and a periphery of the light emitting element; a color resin disposed in the first region; an adhesive film disposed on the color resin and disposed to be spaced apart from the color resin by a predetermined distance; and a light conversion sheet disposed on the adhesive film and having a light conversion pattern disposed in correspondence with a location of the light emitting element.

Description

A backlight unit and a display device including the same{BACK LIGHT UNIT AND DIPLAY INCLUDING THE SAME}

Embodiments of the present invention relate to a backlight unit and a display device including the same.

A liquid crystal display (Liquid Crystal Display) is one of the flat panel display that displays an image using a liquid crystal (Liquid Crystal), it is widely used throughout the industry due to the advantages of thin, light and low power consumption. The liquid crystal display may display an image by adjusting the transmittance of light emitted from the backlight unit in response to a characteristic in which the transmittance is adjusted by changing the arrangement of the liquid crystal. The liquid crystal display device includes a light emitting diode (Light Emitting Diode), a CCFL (Cold Cathode Fluorescent Lamp), and a HCLF (Hot Cathode Fluorescent Lamp). Recently, light-emitting diodes having excellent light efficiency and high color reproduction are 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 source and the transmission mode of light. In the direct-type backlight unit, a light source such as an LED may be disposed on the rear surface of the display device.

The light source device used in such a direct type backlight unit may include a light emitting diode, a substrate including a light emitting diode and a circuit element for driving the light emitting diode. In addition, a phosphor film containing an expensive phosphor may be disposed on the light emitting diode so that light emitted from the light emitting device is excited to exhibit color. However, since the phosphor film has a large amount of phosphor used, the manufacturing cost of the backlight unit may increase. In addition, if the light emitted from the light emitting device is not sufficiently excited, there is a problem in that the color reproduction rate decreases.

An object of embodiments of the present invention is to provide a backlight unit having a high color gamut and a display device including the same.

In addition, another object of embodiments of the present invention is to provide a backlight unit and a display device including the same, which can reduce manufacturing cost.

In one aspect, embodiments of the present invention, a light emitting device having a flip-chip structure, a first reflector disposed in a form surrounding the first area including the light emitting device and the light emitting device, a color resin disposed in the first area, A backlight unit comprising a light conversion sheet disposed on a color resin, an adhesive film disposed to be spaced a predetermined distance from the color resin, and a light conversion sheet disposed on the adhesive film and having a light conversion pattern corresponding to the position of the light emitting device. Is to provide

In another aspect, embodiments of the present invention include a display panel, a backlight unit disposed under the display panel and irradiating light to the display panel, the backlight unit comprising: a light emitting device having a flip chip structure, a light emitting device, A first reflector disposed in a form surrounding the first area including the periphery of the light emitting element, a color resin disposed in the first area, an adhesive film disposed on the color resin, and spaced apart from the color resin by a predetermined distance, and adhesion It is to provide a display device including a light conversion sheet having a light conversion pattern disposed on a film and corresponding to a position of a light emitting device.

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

In addition, according to embodiments of the present invention, it is possible to provide a backlight unit capable of reducing manufacturing cost and a display device including the same.

1 is a structural diagram showing an embodiment of a display device according to the present invention.
2 is a diagram illustrating an example of a structure of a backlight unit included in a display device according to embodiments of the present invention.
3A to 3E are views illustrating an example of a specific structure of the backlight unit illustrated in FIG. 2.
4 is a view showing a first embodiment of the structure of a backlight unit according to embodiments of the present invention.
5A and 5B are views illustrating an example of a structure according to the position of the light conversion pattern included in the backlight unit shown in FIG. 4.
FIG. 6 is a structural diagram showing a first embodiment of the backlight unit shown in FIG. 1.
7 is a perspective view illustrating a reflector employed in the backlight unit illustrated in FIG. 1.
8 is a conceptual diagram illustrating a path of light emitted from a light emitting element in the backlight unit illustrated in FIG. 6.
9A to 9F are conceptual views illustrating a process of manufacturing the backlight unit illustrated in FIG. 6.
10 is a structural diagram illustrating a second embodiment of the backlight unit shown in FIG. 1.
FIG. 11 is a structural diagram illustrating a third embodiment of the backlight unit shown in FIG. 1.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and the ordinary knowledge in the technical field to which the present invention pertains. It is provided to fully inform the holder of the scope of the invention, and the invention is only defined by the scope of the claims.

In addition, the shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are exemplary, and the present invention is not limited to the illustrated matters. Throughout the specification, the same reference numerals refer to the same components. In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known technologies may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted. do. When'include','have','consist of', etc. mentioned in this specification are used, other parts may be added unless'~man' is used. When a component is expressed in singular, it may include a case in which plural is included unless specifically stated.

In addition, in interpreting the components in the embodiments of the present invention, it should be interpreted as including an error range even if there is no explicit description.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the essence, order, order, or number of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected to or connected to the other component, but different components between each component It will be understood that the "intervenes" may be, or each component may be "connected", "coupled" or "connected" through other components. In the case of the description of the positional relationship, for example, when the positional relationship of two parts is described as'~top','~upper','~bottom','~side', etc.,'right' Alternatively, one or more other parts may be located between the two parts unless'direct' is used.

In addition, components in the embodiments of the present invention are not limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, the first component mentioned below may be the second component within the technical spirit of the present invention.

In addition, the features (configurations) in the embodiments of the present invention may be partially or wholly combined with each other or combined or separated, and technically various interlocking and driving are possible, and each embodiment is independently performed with respect to each other. It could be possible or it could be done together in an association relationship.

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

1 is a structural diagram showing an embodiment of a display device according to the present invention.

Referring to FIG. 1, the display device 10 may include a display panel 100 and a backlight unit 200 irradiating light to the display panel 100.

The display panel 100 may be a liquid crystal panel. The liquid crystal panel includes a liquid crystal layer in which a difference in transmittance may occur depending on the arrangement of liquid crystal molecules, a pixel electrode selectively applying a voltage to the liquid crystal layer, and a common electrode applying a common voltage to the liquid crystal layer corresponding to the pixel electrode. can do. 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 in correspondence to a voltage applied between the pixel electrode and the common electrode. Also, the display panel 100 may include a color filter. In addition, the display panel 100 may further include a pixel circuit that selectively applies a voltage to the pixel electrode, and a drive circuit that supplies signals and voltages to the pixel circuit.

The backlight unit 200 is disposed under the display panel 100 and uniformly irradiates light to the front surface of the display panel 100 from the bottom of the display panel 100. The backlight unit 200 may generate and irradiate light using a light emitting diode. The backlight unit 200 may be spaced apart from the display panel 100 by a certain distance d1.

2 is a diagram illustrating an example of a structure of a backlight unit included in a display device according to embodiments of the present invention.

Referring to FIG. 2, the display device 10 according to embodiments of the present invention includes a display panel 100 and a backlight unit disposed under the display panel 100 and supplying light to the display panel 100. It may include 200.

Various structures may be disposed between the backlight unit 200 and the display panel 100, and for example, the display panel 100 may be fixed on the backlight unit by the guide panel 400 and the foam pad 500. However, it is not limited thereto.

The backlight unit 200 may include a cover bottom 300 for receiving optical elements or the like constituting the backlight unit 200.

The 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 small mini LED or a miniature micro light emitting diode (μLED). In addition, the light emitting device 211 may be disposed in a form in which the chip type light emitting device 211 is mounted on the substrate 210, thereby reducing the thickness of the backlight unit 200 and also having a wide irradiation angle and light efficiency. It is possible to provide this high light source. The light-emitting element 211 may be referred to as a light-emitting element 211 having a flip-chip structure that has a form in which the chip-shaped light-emitting element 211 is mounted on the substrate 210.

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

The light conversion sheet 216 may be disposed on the light source protection unit 205. The light conversion sheet 216 may include a plurality of light conversion patterns 216p disposed on a surface facing the light emitting device 211. Here, the plurality of light conversion patterns 216p may be disposed at positions corresponding to each of the plurality of light emitting elements 211 on the lower surface of the light conversion sheet 216. In addition, the light conversion pattern 216p may transmit a portion of light emitted from the light emitting element 211. The light conversion sheet 216 may be a light control sheet capable of transmitting a portion of light. The light emitted from the light emitting element 211 by the light conversion pattern 216p is scattered, reflected, diffracted, or transmitted, thereby enhancing the image quality of the backlight unit.

That is, by arranging the light conversion pattern 216p in the region where the intensity of light emitted from the light emitting element 211 is the strongest, between the region where the light emitting element 211 is disposed (the region having a large amount of light) and the light emitting element 211 It is possible to reduce luminance variations and the like between regions (regions having a small amount of light).

The light conversion sheet 216 may include a light conversion material. In addition, the light conversion pattern 216p of the light conversion sheet 216 may include a light conversion material. The photoconversion material may include titanium dioxide (TiO2). In addition, the light conversion material may be white. However, it is not limited thereto.

A diffusion plate 218 for diffusing light incident from the bottom may be disposed on the light conversion sheet 216. In addition, the phosphor film 217 and one or more optical sheets 219 may be disposed on the diffusion plate 218. When the light incident on the phosphor film 217 is blue light, when the light passes through the phosphor film 217, it may be converted into white light.

3A to 3E are views illustrating an example of a specific structure of the backlight unit illustrated in FIG. 2.

Referring to FIG. 3A, a plurality of light emitting elements 211 may be disposed on the substrate 210. A reflective film coated on the substrate 210 may be disposed. The coded reflective film may be 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 of the substrate 210 except for a region in which the light emitting device 211 is disposed.

The reflector 212 may be formed in an area in which an area corresponding to the light emitting device 211 is opened and may be disposed on the substrate 210. In addition, the reflector 212 may reflect light emitted from the light emitting device 211 to the front surface of the backlight unit, thereby improving light efficiency of the backlight unit.

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

Therefore, light emitted in the lateral direction of the light emitting device 211 may be reflected from the side of the reflector 212 and emitted to the front of the backlight unit 200, thereby further enhancing the light efficiency of the backlight unit 200 Can give.

Referring to FIG. 3C, a light source protection unit 205 may be disposed on a plurality of light emitting elements 211 and a reflector 212. The light source protection unit 205 may include, for example, resin. When the light source protection unit 205 includes a resin, a partition wall is disposed outside the substrate 210 or in an outer area of a region in which a plurality of light emitting elements 211 are disposed on the substrate 210, and the resin is inside the partition wall. By applying the light source protection unit 205 may be formed. The light source protection unit 205 functions to protect the plurality of light emitting elements 211 disposed on the substrate 210, and may diffuse light emitted from the light emitting elements 211 to provide a function of the light guide plate. The light emitted from the light emitting element 211 by the light source protection unit 205 allows the light to spread as evenly as possible to the top surface of the light source protection unit 205. At this time, even if the reflector 212 adjusts the direction in which light spreads by the light source protection unit 205, the intensity of light emitted in the vertical direction of the light emitting element 211 may be large, and accordingly, the uniformity of the image is deteriorated. Can be.

According to embodiments of the present invention, the light conversion element 211p having an optical characteristic is disposed on a light source protection unit 205 at a position corresponding to the light emitting element 211, thereby reducing the thickness of the backlight unit 200 and thus generating an image. To improve the uniformity of.

Referring to FIG. 3D, a light conversion sheet 216 may be disposed on the light source protection unit 205, and a plurality of light conversion patterns 216p may be disposed on the lower surface of the light conversion sheet 216. However, the present invention is not limited thereto, and a plurality of light conversion patterns 216p may be disposed on the top surface of the optical sheet 216. In addition, the light conversion sheet 216 may be adhered to the light source protection unit 205 through an adhesive film 215. The adhesive film 215 may be an optical clear adhesive (OCA) film. In addition, the light conversion sheet 216 may be formed of, for example, PET (Polyethylene terephthalate), but is not limited thereto.

Each of the plurality of light conversion patterns 216p disposed on the lower surface or the upper surface of the light conversion sheet 216 may be disposed to correspond to each of the plurality of light emitting elements 211 disposed on the substrate 210. For example, the light conversion pattern 216p may be disposed such that at least a portion overlaps with the light emitting element 211, and considering light diffusion characteristics, it overlaps the region including the region where the light emitting element 211 is disposed. Can be deployed. The light conversion pattern 216p may scatter, reflect, diffract, or transmit light emitted from the light emitting device 211. For example, the light conversion pattern 216p may scatter light emitted from the light emitting element 211 so that light is emitted. In addition, the light emitted in the vertical direction from the light emitting element 211 may be reflected and reflected again by the reflector 212 so that light is emitted to the region between the light emitting elements 211.

As described above, light emitted from the light emitting element 211 by the light conversion pattern 216p is scattered, reflected, diffracted, or transmitted, thereby improving the image quality of the backlight unit 200.

Referring to FIG. 3E, a diffusion plate 218 may be disposed on the light conversion sheet 216, and a phosphor film 217 may be disposed on the diffusion plate 218. Then, one or more optical sheets 219 may be disposed on the phosphor film 217. Here, the positions in which the diffusion plate 218 and the phosphor film 217 are disposed may be interchanged. The diffusion plate 218 may diffuse light emitted through the light conversion sheet 216.

The phosphor film 217 may include a phosphor having a specific color, and excite incident light to emit light in a specific wavelength band. For this reason, the light passing through the phosphor film 217 may be a specific color included in the phosphor film 217 or a color mixed with a specific color. For example, when the light emitting device 211 emits light in the first wavelength band (for example, blue light), the phosphor film 217 reacts to the incident light and light in the second wavelength band (for example, green light). ) And the third wavelength band light (eg, red light) is emitted to finally emit white light. Can be.

In addition, the phosphor film 217 may be disposed in some areas on the diffusion plate 218, depending on the case. For example, when the light emitting device 211 emits light in the blue wavelength band, the phosphor film 217 is only in an area of the display panel 100 except for an area corresponding to an area in which the blue subpixel SP is disposed. It may be deployed. That is, light that does not pass through the phosphor film 217 may reach the blue subpixel SP of the display panel 100. Further, the phosphor film 217 may not be disposed on the display panel 100 according to the light emitting device 211. For example, the light emitting device 211 emits light in the white wavelength band or emits light in the green wavelength band and light in the red wavelength band on the emission surface of the light emitting device 211 that emits light in the blue wavelength band. When the color conversion film is coated, the phosphor film 217 may not be disposed.

As described above, embodiments of the present invention include a light conversion sheet 216 including a light conversion pattern 216p disposed at a position corresponding to the light emitting device 211 and various optical devices, thereby making the backlight unit 200 ) It is possible to improve the image quality of the backlight unit 200 while reducing the thickness.

Hereinafter, embodiments of the present invention will be described together with specific examples of the light conversion pattern 216p disposed on the light conversion sheet 216.

4 is a view showing a first embodiment of the structure of a backlight unit according to embodiments of the present invention.

Referring to FIG. 4, the substrate 210 is disposed on the cover bottom 300, and the substrate 210 is covered by the adhesive tape 210a disposed between the cover bottom 300 and the substrate 210. 300).

A plurality of light emitting elements 211 may be disposed on the substrate 210, and the reflector 212 may be disposed in at least some of the regions except the region in which the light emitting elements 211 are disposed.

Here, the light emitting device 211 may be, for example, a light emitting diode (LED), and includes a light emitting unit 211a including an n-type semiconductor layer, an activation layer, and a p-type semiconductor layer, and an electrode unit 211b. can do. The light source protection unit 205 is disposed on the plurality of light emitting elements 211 and the reflector 212. The light conversion sheet 216 on which the light conversion pattern 216p is disposed may be disposed on the light source protection unit 205 at a position corresponding to the light emitting device 211. In addition, a diffusion plate 218, a phosphor film 217, an optical sheet 219, and the like may be disposed on the light conversion sheet 216.

The light conversion pattern 216p disposed on the lower surface of the light conversion sheet 216 may be implemented by printing a material having light-shielding properties on the light conversion sheet 216, and includes, for example, titanium dioxide (TiO2). The light conversion pattern 216p may be disposed through a method of printing ink on the light conversion sheet 216. Further, the light conversion pattern 216p disposed on the lower surface of the light conversion 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 conversion pattern 216p disposed on the bottom surface of the light conversion sheet 216 may be composed of three layers. The light conversion pattern 216p may be implemented through a method of printing the light blocking material on the light conversion sheet 216 three times, and the area of the light blocking material to be printed may be gradually narrowed. In addition, the light conversion pattern 216p may be disposed on the light emitting device 211 by inverting the light conversion sheet 216 on which the light conversion pattern 216p is disposed and placing it on the light source protection unit 205.

Therefore, the area of the light conversion pattern 216p may be gradually narrowed toward the bottom from the light conversion sheet 216, and the thickness of the central portion of the light conversion pattern 216p may be greater than the thickness of the outer portion.

That is, since the intensity of light emitted in the vertical direction from the light emitting element 211 is the largest, the central portion of the light conversion pattern 216p may be disposed thicker. However, it is not limited thereto.

As described above, by allowing the light conversion pattern 216p to be disposed on the light emitting device 211, at least a portion of the light emitted in the vertical direction from the light emitting device 211 is blocked, and thus a hot spot in the area where the light emitting device 211 is disposed. This can be prevented from appearing. The light conversion sheet 216 on which the light conversion pattern 216p is disposed may be adhered to the light source protection unit 205 by an adhesive film 215. At this time, the adhesive film 215 may be disposed on at least some of the areas except the area where the light conversion pattern 216p is disposed on the lower surface of the light conversion sheet 216.

Therefore, the adhesive film 215 may not be disposed in the area where the light conversion pattern 216p is disposed, and an air gap may exist between the light conversion pattern 216p and the light source protection unit 205. Further, the side portion of the light conversion pattern 216p and the adhesive film 215 may be spaced apart from each other. As an air gap exists between the light conversion pattern 216p and the light source protection unit 205, light emitted in the lateral direction of the light conversion pattern 216p may be reflected by the air gap. That is, light emitted in the lateral direction of the light conversion pattern 216p may be emitted at a large refractive angle or reflected from the air layer by the air layer having a low refractive index. In addition, light reflected from the air layer is reflected and emitted again by the reflector 212, thereby improving light efficiency while assisting the light blocking function of the light conversion pattern 216p.

As described above, through the structure in which the light conversion element 211 and the light conversion pattern 216p and the air gap are disposed at a position corresponding to the light emitting device 211, light efficiency of the backlight unit may be increased while preventing hot spots. Further, the light conversion pattern 216p disposed under the light conversion sheet 216 may be arranged in a different structure according to the position.

5A and 5B are views illustrating an example of a structure according to the position of the light conversion pattern included in the backlight unit shown in FIG. 4.

Referring to FIG. 5A, as an example of the luminance displayed through the backlight unit according to the structure of the light conversion pattern 311, <EX1> is the luminance measured when the light conversion pattern 216p is arranged in a constant structure. An example is shown, and <EX2> represents an example of luminance measured when the light conversion pattern 216p is arranged in a different structure according to the position.

As shown in <EX1> of FIG. 5A, when the structure of the light conversion pattern 216pa disposed in the outer area of the backlight unit 200 and the light conversion pattern 216pd disposed in the central area are the same, the outer surface of the backlight unit The luminance of the region may appear low.

That is, since the number of light emitting elements 211 for supplying light to the corresponding area is relatively small in the outer area of the backlight unit, when the light conversion pattern 216p having the same level of light blocking property is disposed, it is located in the central area of the backlight unit. In comparison, luminance may be lowered.

Therefore, as shown in <EX2> of FIG. 5A, the structure of the light conversion pattern 216pa disposed in the outer region of the backlight unit 200 and the light conversion pattern 216pd disposed in the central region are different from each other. By doing so, it is possible to prevent a decrease in luminance in the outer region of the backlight unit 200 and make the overall luminance uniform.

For example, the light conversion pattern 216p such that the thickness T1 of the light conversion pattern 216pa disposed in the outer area of the backlight unit 200 is smaller than the thickness T2 of the light conversion pattern 216pd disposed in the central area. ) May be disposed.

Alternatively, the light conversion pattern (so that the area W1 of the thickest part in the light conversion pattern 216pb disposed adjacent to the outer area of the backlight unit is smaller than the area W2 of the thickest part in the light conversion pattern 216pd. 216p) may be disposed. That is, the area of the portion having high blocking characteristics in the light conversion patterns 216pa and 216pb disposed in the outer region or the region adjacent to the outer region of the backlight unit 200 may be small.

In addition, the thickness of the light conversion pattern 216p gradually decreases from the center area to the outer area of the backlight unit 200, or the light conversion pattern ( 216p) may be disposed. That is, the area of the portion having high blocking characteristics in the light conversion patterns 216pa and 216pb disposed in the outer region or the region adjacent to the outer region of the backlight unit 200 may be reduced.

In addition, the thickness of the light conversion pattern 216p gradually decreases from the center area to the outer area of the backlight unit 200, or the light conversion pattern ( 216p) may be disposed.

In addition, depending on the case, the number of light emitting elements 211 or the distance between the light emitting elements 211 in the central region and the outer region of the backlight unit 200 are differently arranged, so that the light conversion patterns 216p may be differently arranged. have.

5B, another example of a structure in which the light conversion pattern 216p is disposed on the bottom surface of the light conversion sheet 216 is shown.

Here, the distance between the light emitting elements 211 disposed in the outer region of the backlight unit 200 may be narrower than the distance between the light emitting elements 211 disposed in the central region of the backlight unit 200. That is, the light emitting device 211 may be disposed in a more dense structure in the outer region of the backlight unit 200 so that the luminance of the central region and the outer region of the backlight unit 200 is uniform.

In addition, since the light conversion pattern 216p disposed on the lower surface of the light conversion sheet 216 is disposed to correspond to the light emitting device 211, between the light conversion patterns 216p disposed in the outer region of the backlight unit 200 The spacing may be different from the spacing between the light conversion patterns 216p disposed in the central region.

For example, the distance D1 of the light conversion pattern 216p disposed in the outer region of the backlight unit 200 in the first direction is the distance in the first direction of the light conversion pattern 216p disposed in the central region ( D2). In addition, the distance D3 in the second direction of the light conversion pattern 216p disposed in the outer area of the backlight unit 200 is the distance D4 in the second direction of the light conversion pattern 216p disposed in the central area. ).

At this time, the size and thickness of the light conversion pattern 216p disposed in the outer region of the backlight unit may be different from the size and thickness of the light conversion pattern 216p disposed in the central region of the backlight unit.

For example, as illustrated in FIG. 5B, the size S1 of the light conversion patterns 216pe and 216pf disposed in the outer area of the backlight unit 200 is the light conversion pattern 216pg arranged in the central area of the backlight unit. ) May be smaller than the size S2.

Alternatively, the light conversion pattern 216p may have a multi-layer structure as described above, and in this case, the area of the part having the greatest thickness or thickness of the light conversion patterns 216pe and 216pf disposed in the outer region of the backlight unit is a backlight. The thickness or thickness of the light conversion pattern 216pg disposed in the central region of the unit 200 may be smaller than the area of the largest portion.

That is, by reducing the size of the light conversion patterns 216pe and 216pf disposed in the outer region of the backlight unit, it is possible to be disposed in correspondence with the light emitting elements 211 arranged at a narrow interval. Therefore, it is possible to prevent a hot spot from being generated at a position corresponding to the light emitting element 211 in the outer region of the backlight unit 200.

In addition, by lowering the level at which light emitted from the light emitting device 211 is blocked in the outer region of the backlight unit 200, the amount of light emitted is increased and the luminance of the outer region of the backlight unit 200 is prevented from deteriorating. It is possible to display uniform luminance in the entire region of (200).

As described above, by differently arranging the structure of the light conversion pattern 216p for each region of the backlight unit 200, it is possible to prevent luminance from being lowered in the outer region of the backlight unit 200 and improve luminance uniformity.

In addition, a hot spot of the backlight unit 200 may be prevented and luminance uniformity may be improved through a structure in which the above-described light conversion pattern 216p is disposed.

In addition, embodiments of the present invention, by diffracting the light emitted in the vertical direction of the light emitting element (216p), it is possible to provide a method to improve the image quality of the backlight unit and improve the light efficiency.

FIG. 6 is a structural diagram showing a second embodiment of the backlight unit shown in FIG. 1, and FIG. 7 is a perspective view showing a reflector employed in the backlight unit shown in FIG. 1.

Referring to FIGS. 6 and 7, the backlight unit 200a is disposed on the substrate 210 and includes a light emitting device 211 having a flip chip structure, a first area including the light emitting device 211 and surroundings of the light emitting device. The reflector 212 disposed in the form surrounding the (1AR), the color resin 213 disposed in the first area 1AR, and the color resin 213 are disposed on the color resin 213 so as to be spaced apart by a predetermined distance. It may include a light conversion sheet 216 disposed on the adhesive film 215 and the adhesive film 215 to be disposed, and having a light conversion pattern (216p) disposed in response to the position of the light emitting device 211. .

The light emitting device 211 may have a flip chip structure. The light emitting element 211 may emit blue light. However, the color of the light emitted by the light emitting element 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 cause light emitted from the light emitting device 211 to be reflected. The reflector 212 may be disposed on the substrate 210. The reflector 212 may include a hole corresponding to the first area 1AR, as shown in FIG. 3. When the reflector 212 is disposed on the substrate 210, the first region 1AR on the substrate 210 may be exposed in response to a 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 photo solder resist (PSR). However, it is not limited thereto. Here, the hole corresponding to the first region 1AR is illustrated as being circular, but is not limited thereto.

The color resin 213 may be disposed in the first area 1AR. The color resin 213 may be disposed only in the first area 1AR by a hole. The color resin 213 may be cured by ultraviolet light. After the color resin 213 is disposed in the first region 1AR, it may be cured using ultraviolet light. The color resin 213 may include a red phosphor. The light passing through the color resin 213 may be purple. However, it is not limited thereto. Since the color resin 213 is disposed only in the first area 1AR, the use of the phosphor can be reduced, thereby reducing manufacturing cost.

The adhesive film 215 may be disposed on the color resin 213. The adhesive film 215 may include resin. The refractive index of the adhesive film 215 may be the same or similar to that of the color resin 213. However, it is not limited thereto. The adhesive film 215 may be disposed to be spaced a predetermined distance from the color resin 213. That is, a predetermined material 214 having a different refractive index from the color resin 213 may be disposed between the adhesive film 215 and the color resin 213. The predetermined material 214 and the color resin 213 may be in contact with each other so that light is totally reflected at the boundary between the predetermined material 214 and the color resin 213. The angle at which light is totally reflected may correspond to a difference in refractive index between the predetermined material 214 and the color resin 213. The predetermined material 214 may be a material having a refractive index in the range of 1 to 1.46. Also, the predetermined material 214 may be air. However, it is not limited thereto.

The light conversion sheet 216 may include a light conversion pattern 216p. The light conversion sheet 216 may be disposed on the adhesive film 215 so that the light conversion pattern 216p is disposed at a position corresponding to the light emitting device 211. By blocking the light in the vertical direction emitted from the light emitting element by the light conversion pattern 216p, it is possible to prevent hot spots from being generated. The light conversion pattern 216p may reflect incident light.

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

In one embodiment, a reflector 212a may be further disposed on the light emitting device 211. The reflector 212a disposed on the light emitting device 211 may be a distributed Bragg reflector. However, it is not limited thereto. A light having a path in the vertical direction or a direction close to the vertical direction may be reflected from the light emitting device 211 by the reflector 212a.

8 is a conceptual diagram illustrating a path of light emitted from a light emitting element in the backlight unit illustrated in FIG. 6.

Referring to FIG. 8, the light emitting device 211 may be disposed in the color resin 213. Accordingly, when the light emitted from the light emitting element 211 passes through the color resin 213, the light emitted from the light emitting element 211 is excited to mix the color of the phosphor contained in the color resin 213. Can have energy. For example, when the light emitting device 211 emits blue light and the color resin 213 includes a red phosphor, the light passing through the color resin 213 may have a purple color. However, a difference may occur in the degree of color mixing depending on the path of light. For example, among the light emitted from the light emitting element 211, the light of the first group (A) has a problem that the color resin 213 passing through is thin so that colors are not sufficiently mixed. However, the light emitted from the light emitting device 211 corresponding to the second group (B) passes through the color resin 213 and is reflected by the reflector 212 and then projected back to the color resin 213. It can go outside. Due to this, a difference in color reproduction may occur between the light of the first group (A) and the light of the second group (B). Then, the color reproduction rate of the backlight unit 200a is lowered by the light of the first group A, which causes a problem.

In order to solve the above problems, at least a part of the light of the first group (A) is colored resin 213 due to a difference in refractive index with a material disposed on the upper portion of the colored resin 213 at the boundary of the upper portion of the colored resin 213 ). When the path of the first path A is changed due to total reflection, that is, the light of the first group A emitted from the light emitting element 211 may be the light of the third group C. The light of the third group (C) is reflected at the boundary of the color resin 213 and then directed back to the color resin 213 and then reflected by the reflector 212 and irradiated to the outside. Due to this, the color reproduction rate of the backlight unit 200a may be increased.

1)를 크게 할 수 있고 각도(

1)를 크게 되면,컬러레진(213)의 경계에서 전반사가 되는 광의 양을 크게 할 수 있다. In addition, a material having a different refractive index from the color resin 213 may be disposed on the upper portion of the color resin 213 in order to make total reflection at the boundary of the color resin 213. In addition, by setting a large difference in the refractive index of the material disposed on the color resin 213 and the color resin 213, the angle at which the total reflection is made at the boundary of the color resin 213 (

1) can be enlarged and angle(

When 1) is increased, the amount of light that is totally reflected at the boundary of the color resin 213 can be increased.

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

As illustrated in FIG. 9A, the backlight unit 200a may arrange the light emitting device 211 on the substrate 210. The light emitting device 211 may have a flip chip structure directly connected to the substrate 210. The light emitting device 211 may be disposed to correspond to the first area 1AR on the substrate 210. The light emitting device 211 may be disposed at the center of the first area 1AR. Here, the number of light emitting elements 211 disposed on the substrate 210 is shown as three, but is not limited thereto. The substrate 210 may include a reflective material to reflect light. In addition, a white pigment may be applied to the substrate 210. In addition, the reflector 212a may be further disposed on the light emitting device 211 as illustrated in FIG. 6. The reflector 212a disposed on the light emitting device 211 may be a distributed Bragg reflector.

And, as illustrated in FIG. 9B, the reflector 212 may be disposed on the substrate 210. The reflector 212 may include a hole having a constant diameter, and the hole may correspond to the first area 1AR. Therefore, the first region 1AR on the substrate 210 may not be covered by the reflector 212.

Then, as illustrated in FIG. 9C, the color resin 213 is introduced into the first region 1AR corresponding to the hole of the reflector 212 and cured with ultraviolet rays. The upper surface of the color 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 color resin 213. Here, the upper surface of the color resin 213 is illustrated as being parallel to the horizontal surface, but is not limited thereto, and the upper surface of the color resin 213 may be concave or convex. However, the highest point of the upper surface of the color resin 213 is lower than the height of the reflector 212.

In addition, as shown in FIG. 9D, the adhesive film 215 may be disposed on the substrate 210 on which the reflector 212 is disposed. The adhesive film 215 may be disposed such that the height of the reflector 212 is higher than that of the color resin 213 so that the adhesive film 215 has a constant distance from the color resin 213 on the color resin 213. A predetermined material 214 may be disposed at regular intervals. The desired material 214 can be air. However, the present invention is not limited thereto, and the color resin 213 and the refractive index may be different materials. The adhesive film 215 may be a material that can transmit light.

And, as shown in Figure 9e, it is possible to place the light conversion sheet 216 on the adhesive film 215. The light conversion sheet 216 includes a light conversion pattern 216p, and the light conversion pattern 216p may correspond to a position where the light emitting device 211 is disposed. A light spot emitted from the light emitting device 211 at an angle close to vertical or vertical is blocked by the light conversion pattern 216p included in the light conversion sheet 216 to generate a hot spot in the backlight unit 200 shown in FIG. 1. Can be prevented.

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

10 is a structural diagram illustrating a second embodiment of the backlight unit shown in FIG. 1.

Referring to FIG. 10, the backlight unit 200b is disposed on the substrate 210 and includes a light emitting device 211 having a flip-chip structure, a first area 1AR including the light emitting device 211 and the surroundings of the light emitting device. ) Is disposed to surround the reflector 212, the color resin 213 disposed in the first area (1AR), the color resin 213 is disposed on, the color resin 213 is disposed to be spaced apart a predetermined distance It may be disposed on the film 215 and the adhesive film 215, and may include a light conversion sheet 216 having a light conversion pattern (216p) disposed in response to the position of the light emitting device 211.

The light emitting element 211 may emit blue light. However, it 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 cause light emitted from the light emitting device 211 to be reflected. The reflector 212 may be disposed on the substrate 210. The reflector 212 may be the same as the reflector 212 illustrated in FIG. 3 and may include holes corresponding to the first region 1AR. When the reflector 212 is disposed on the substrate 210, the first region 1AR on the substrate 210 may be exposed in response to a hole. The reflector 212 may be coated with a white pigment to reflect light. The white pigment may include photo solder resist (PSR). However, it is not limited thereto. Here, the hole corresponding to the first region 1AR is illustrated as being circular, but is not limited thereto.

The color resin 213 may be disposed in the first area 1AR. The color resin 213 may be disposed only in the first area 1AR by a hole. The color resin 213 may be cured by ultraviolet light. After the color resin 213 is disposed in the first region 1AR, it may be cured using ultraviolet light. The color resin 213 may include a yellow phosphor. In addition, the color resin 213 may include a red phosphor and a green phosphor. The light passing through the color resin 213 may be purple. However, it is not limited thereto. Since the color resin 213 is disposed only in the first area 1AR, the use of the phosphor can be reduced, thereby reducing manufacturing cost.

The adhesive film 215 may be disposed on the color resin 213. The adhesive film 215 may include resin. The refractive index of the adhesive film 215 may be the same or similar to that of the color resin 213. However, it is not limited thereto. The adhesive film 215 may be an optical clear adhesive (OCA) film. The adhesive film 215 may be disposed to be spaced a predetermined distance from the color resin 213. That is, a predetermined material 314 having a different refractive index from the color resin 213 may be disposed between the adhesive film 215 and the color resin 213. The predetermined material 314 and the color resin 213 may be in contact with each other so that light is totally reflected at the boundary between the predetermined material 314 and the color resin 213. The angle at which light is totally reflected may correspond to a difference in refractive index between the predetermined material 314 and the color resin 213. The desired material can be air. However, it is not limited thereto.

The light conversion sheet 216 may include a light conversion pattern 216p. The light conversion sheet 216 may be disposed on the adhesive film 215 so that the light conversion pattern 216p is disposed at a position corresponding to the light emitting device 211. By blocking the light having a path in the vertical direction and a path close to the vertical direction emitted from the light emitting device by the light conversion pattern 216p, it is possible to prevent a hot spot from being generated in the backlight unit 200b. The light conversion pattern 216p may have a shape as shown in FIG. 4.

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

Accordingly, the color resin 213 includes two phosphors having different colors or has phosphors having two colors, so that the backlight unit may not include the phosphor film 217 on top of the light conversion sheet. have. Accordingly, the amount of phosphors used in the backlight unit 200 can be reduced, thereby reducing manufacturing costs.

FIG. 11 is a structural diagram showing a third embodiment of the backlight unit shown in FIG. 1.

Referring to FIG. 11, the backlight unit 200c is disposed on the substrate 210, the light emitting device 211 having a flip chip structure, the color resin 213 disposed in the first area 1AR, and the color resin ( 213) is disposed on the adhesive film 215 and the adhesive film 215 are disposed to be spaced a predetermined distance from the color resin 213, the light conversion pattern is disposed in correspondence with the position of the light emitting device 211 A light conversion sheet 216 having (216p) may be included.

The light emitting device 211 may have a flip chip structure. The flip-chip structure allows the light emitting element 211 to be directly disposed on the substrate 210 without mounting the light emitting element 211 in a package, thereby making it possible to manufacture a light source having a light and wide irradiation angle. The light emitting element 211 may emit blue light. However, it 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 region 1AR may be formed on the substrate 210. The light emitting device 211 may be disposed in the groove ca. The outer wall of the groove ca of the substrate 210 may serve as a reflector. A white pigment may be applied to the substrate 210 so that the outer wall of the groove ca serves as a reflector. That is, the substrate 210 and the white pigment applied on the substrate 210 may serve as a reflector. The white pigment may include photo solder resist (PSR). However, it is not limited thereto. Here, the groove ca corresponding to the first region 1AR is illustrated as being circular, but is not limited thereto.

The color resin 213 may be disposed in the first area 1AR. The color resin 213 may be disposed only in the first area 1AR by the groove ca. The color resin 213 may be cured by ultraviolet light. After the color resin 213 is disposed in the first region 1AR, it may be cured using ultraviolet light. The color resin 213 may include a red phosphor. However, it is not limited thereto, and the color resin 213 may include a yellow phosphor. In addition, the color resin 213 may include a red phosphor and a green phosphor. The light passing through the color resin 213 may be purple. However, it is not limited thereto. Since the color resin 213 is disposed only in the first area 1AR, use of the phosphor can be reduced.

The adhesive film 215 may be disposed on the color resin 213. The adhesive film 215 may include resin. The refractive index of the adhesive film 215 may be the same or similar to that of the color resin 213. However, it is not limited thereto. The adhesive film 215 may be an optical clear adhesive (OCA) film. The adhesive film 215 may be disposed to be spaced a predetermined distance from the color resin 213. That is, a predetermined material 214 having a different refractive index from the color resin 213 may be disposed between the adhesive film 215 and the color resin 213. The predetermined material 214 and the color resin 213 may be in contact with each other so that light is totally reflected at the boundary between the predetermined material 214 and the color resin 213. The angle at which light is totally reflected may correspond to a difference in refractive index between the predetermined material 214 and the color resin 213. The predetermined material 214 may be a material having a refractive index in the range of 1 to 1.46. Also, the predetermined material 214 may be air. However, it is not limited thereto.

The light conversion sheet 216 may include a light conversion pattern 216p. The light conversion sheet 216 may be disposed on the adhesive film 215 so that the light conversion pattern 216p is disposed at a position corresponding to the light emitting device 211. The light conversion pattern 216p may block light having a vertical path emitted from the light emitting element or light having a path adjacent to the vertical direction, thereby preventing hot spots from being generated in the backlight unit 200c. The light conversion pattern 216p may have a shape as shown in FIG. 4. However, it is not limited thereto.

The phosphor film 217 may be disposed on the light conversion sheet 216. The phosphor film 217 may include a green phosphor. However, it 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 valued on the light conversion sheet 216.

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

The above description and the accompanying drawings are merely illustrative of the technical spirit of the present invention, and those of ordinary skill in the art to which the present invention pertains combine configurations in a range that does not depart from the essential characteristics of the present invention. , Various modifications and variations such as separation, substitution and change will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

10: display device
100: display panel
200: backlight unit
210: substrate
211: light emitting element
212: Reflector
213: color resin
214: predetermined substance
215: adhesive film
216: light conversion sheet
217: phosphor film
218: diffuser plate
219: Optical sheet

Claims (14)

A light emitting device having a flip chip structure;
A first reflector disposed in a shape surrounding the light emitting device and a first area including the light emitting device;
A color resin disposed in the first region;
An adhesive film disposed on the color resin and disposed to be spaced a predetermined distance from the color resin; And
A backlight unit including a light conversion sheet disposed on the adhesive film and having a light conversion pattern disposed in correspondence with the position of the light emitting element.
According to claim 1,
A backlight unit in which a material having a different refractive index from the color resin is disposed between the adhesive film and the color resin.
According to claim 1,
The height of the reflector is a backlight unit higher than the height of the color resin.
According to claim 1,
A groove corresponding to the first area is formed on the substrate, and the first reflector includes a backlight unit including the substrate and a reflective film applied to the substrate.
According to claim 1,
A backlight unit in which a phosphor film including a phosphor of a different color from the color resin is disposed on the light conversion sheet.
According to claim 1,
The color resin is a backlight unit comprising two types of phosphors having different colors.
According to claim 1,
A backlight unit on which a second reflector is disposed on an upper surface of the light emitting element.
Display panel;
It is disposed under the display panel and includes a backlight unit for irradiating light to the display panel,
The backlight unit,
A light emitting device having a flip chip structure;
A first reflector disposed in a shape surrounding the light emitting device and a first area including the light emitting device;
A color resin disposed in the first region;
An adhesive film disposed on the color resin and disposed to be spaced a predetermined distance from the color resin; And
A display device including a light conversion sheet disposed on the adhesive film and having a light conversion pattern disposed in correspondence with the position of the light emitting element.
The method of claim 8,
A display device in which a material having a different refractive index from the color resin is disposed between the adhesive film and the color resin.
The method of claim 8,
The height of the first reflector is higher than that of the color resin.
The method of claim 8,
A display device corresponding to the first region is formed on the substrate, and the first reflector includes the substrate and a reflective film applied to the substrate.
The method of claim 8,
A display device including a phosphor film including a phosphor having a color different from that of the color resin on the light conversion sheet.
The method of claim 8,
The color resin is a display device including two types of phosphors having different colors.
The method of claim 8,
A display device having a second reflector disposed on an upper surface of the light emitting device.

Images