KR102310178B1 - Backlight unit and display device comprising the same - Google Patents

Abstract

A backlight unit according to an embodiment includes a light source mounted on a printed circuit board; a reflective member disposed on the printed circuit board; and a light conversion member disposed above the light source, wherein the reflecting member includes: a first reflecting member disposed in contact with the printed circuit board; and a second reflective part bent and extended from the first reflective part.

Description

A backlight unit and a display device including the same

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

Among display devices, there is a device that requires a backlight unit capable of generating light in order to display an image. The backlight unit is a device for supplying light to a display panel including liquid crystal, and includes a light emitting device and means for effectively transmitting the light output from the light emitting device to the liquid crystal side.

As a light source of such a display device, an LED (Light Emitting Diode) or the like may be applied. In addition, in order to effectively transmit the light output from the light source to the display panel side, an optical sheet or the like may be stacked and used.

In this case, an optical member or the like that causes white light to be incident on the display panel by changing the wavelength of light generated from the light source may be applied to the display device. In particular, in order to change the wavelength of light, quantum dots or the like may be used.

Such a display device may include a backlight unit and a liquid crystal panel.

The backlight unit emits light in the direction of the liquid crystal panel, and various members such as a light source, a diffusion member controlling the light emitted from the light source, a reflective member or a light conversion member may be disposed, and these members are the bottom cover can be accepted in

On the other hand, when the light is emitted in the direction of the liquid crystal panel, the light passing through the edge of the emitted light does not pass through the light conversion member, but is incident on the liquid crystal panel.

Accordingly, there is a need for a display device having a new structure capable of solving the above problems.

SUMMARY Embodiments provide a backlight unit having improved color uniformity and luminance and a display device including the same.

A backlight unit according to an embodiment includes a light source mounted on a printed circuit board; a reflective member disposed on the printed circuit board; and a first light conversion member disposed on the light source, wherein the reflecting member includes: a first reflecting member disposed in contact with the printed circuit board; and a second reflective part bent and extended from the first reflective part.

A backlight unit and a display device including the same according to an embodiment may include a first reflector and a second reflector bent from the first reflector.

That is, by disposing the second reflection unit in the edge region of the backlight unit, light passing through the edge region may be reflected through the second reflection unit to pass through the light conversion member.

Accordingly, it is possible to prevent a decrease in color uniformity of light due to the light passing through the light conversion member in the edge region of the backlight unit.

Accordingly, the color of light emitted from the light source and incident in the direction of the liquid crystal panel can be made uniform as a whole, thereby realizing a uniform screen.

In addition, in the backlight unit and the display device including the same according to the embodiment, by adding a second light conversion member to the edge area, light emitted from the light source and passing through the edge area and/or the light emitted from the light source and the second reflection unit The wavelength of light reflected from and passing through the edge region may be converted by the second light conversion member.

Accordingly, since the edge region is irradiated in the direction of the liquid crystal panel without passing through the light conversion member, it is possible to prevent the blue color from darkening compared to other regions, and thus the overall color uniformity can be improved.

In addition, the display device according to the embodiment may reduce a color difference between the edge region and the center region by differentiating concentrations of light conversion particles in the edge region and the central region of the light conversion layer.

1 is a diagram illustrating a perspective view of a display device according to an exemplary embodiment.
2 is a diagram illustrating a perspective view of a light conversion member according to an embodiment.
3 and 4 are views illustrating a cross-sectional view taken along a region BB′ of FIG. 2 .
5 is a view showing an example of a round prism film according to the embodiment.
6 and 7 are views illustrating a cross-sectional view taken along line A-A' of FIG. 1 according to an exemplary embodiment.
8 and 9 are cross-sectional views taken along line A-A' of FIG. 1 according to another embodiment.
10 is a diagram illustrating a perspective view of a light conversion layer according to another embodiment.
11 and 12 are cross-sectional views taken along line A-A' of FIG. 1 according to another embodiment.
13 is a diagram for describing an arrangement of a light source of a display panel according to another exemplary embodiment.
14 and 15 are views illustrating cross-sectional views according to another embodiment taken along line A-A' of FIG. 1 .

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless otherwise explicitly stated.

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

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between the two parts unless 'directly' is used. Also, in the backlight unit of the present invention, 'upper' and 'lower', when applied to a display device, define a side that is relatively close to the display panel as an upper side and a side that is relatively far from the display panel as a lower side. In addition, in the display panel of the present invention, when 'upper' and 'lower' are applied to a display device, the side relatively close to the backlight unit is referred to as 'lower', and the side relatively far from the backlight unit is referred to as 'upper'. define.

In the case of a description of a temporal relationship, for example, when a temporal relationship is described as 'after', 'following', 'after', 'before', etc., 'immediately' or 'directly' This includes cases that are not continuous unless ' is used.

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

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

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms.

Referring to FIG. 1 , the display device according to the embodiment may include a backlight unit 10 and a liquid crystal panel 20 .

The backlight unit 10 may emit light to the liquid crystal panel 20 . The backlight unit 10 may uniformly radiate light to the lower surface of the liquid crystal panel 20 as a surface light source.

The backlight unit 10 may be disposed under the liquid crystal panel 20 . The backlight unit 10 may include a bottom cover 100 , a printed circuit board 200 , a light source 300 , a reflective member 400 , and a light conversion member 500 .

The bottom cover 100 may have an open top shape. In detail, the bottom cover 100 may have a shape in which a lower portion is closed and an upper portion is opened. The bottom cover 100 may accommodate the printed circuit board 200 , the light source 300 , the reflective member 400 , and the light conversion member 500 .

The printed circuit board 200 may be accommodated in the bottom cover 100 . The printed circuit board 200 may be disposed inside the bottom cover 100 . For example, the printed circuit board 200 may be disposed in direct or indirect contact with at least one surface of the bottom cover 100 .

The printed circuit board 200 may mount the light source 300 . In addition, the printed circuit board 200 may be rigid or flexible.

The light source 300 may generate light in the direction of the liquid crystal panel 20 . In detail, the light source 300 may include a plurality of light emitting diodes. The light source 300 may be a blue light emitting diode emitting blue light or a UV light emitting diode emitting ultraviolet light. That is, the light source 300 may generate blue light having a wavelength range of about 430 nm to about 470 nm or ultraviolet light having a wavelength range of about 300 nm to about 400 nm.

The light source 300 may be mounted on the printed circuit board 200 . For example, the printed circuit board 200 and the light source 300 may be electrically connected, and the light source 300 may be driven by receiving a driving signal through the printed circuit board 200 .

The light source 300 , that is, a plurality of light emitting diodes may be mounted on the printed circuit board 200 to be spaced apart from each other. For example, the plurality of light emitting diodes may be spaced apart from each other at regular or random intervals, and may be mounted and disposed on the printed circuit board 200 .

A reflective member 400 may be disposed on the printed circuit board 200 . In detail, a first reflective member 410 and a second reflective member 420 may be disposed on the printed circuit board 200 .

For example, the first reflective member 410 may be disposed on the printed circuit board 200 , and the second reflective member 420 may be disposed on the first reflective member 410 .

The first reflective member 410 may be a reflective sheet. Also, in the first reflective member 410 , a hole may be formed in a region corresponding to a region in which the light source 300 mounted on the printed circuit board 200 is disposed. Accordingly, the light source 300 may be disposed on the printed circuit board 200 only on an area where the light source 300 is not disposed.

The first reflective member 410 is disposed on the printed circuit board 200, reflects the light emitted from the light source 300 and incident in the direction of the second reflective member 410, and then back to the liquid crystal panel ( 20) direction can reflect light.

The second reflective member 420 may be disposed to be spaced apart from the first reflective member 410 . In detail, the first reflective member 410 and the second reflective member 420 are disposed to be spaced apart from each other, and the light source 300 is disposed between the first reflective member 410 and the second reflective member 420 . This can be placed

A spacer 450 may be disposed between the first reflective member 410 and the second reflective member 420 . The spacer 450 is disposed between the first reflective member 410 and the second reflective member 420 to control a distance between the first reflective member 410 and the second reflective member 420 . can do. That is, the distance between the first reflective member 410 and the second reflective member 420 may be controlled to a desired distance through the spacer 450 .

The second reflective member 420 may include an opening 421 and a closed portion 422 . In detail, the second reflective member 420 may include the opening 421 through which the light emitted from the light source 300 is transmitted and the closed portion 422 through which the light is not transmitted.

The opening 421 and the closing part 422 may be alternately disposed with each other. In detail, referring to FIG. 2 , the second reflective member 420 may include a plurality of openings 421 and closed portions 422 , and the openings 421 and the closed portions 422 are They may be placed alternately with each other.

That is, the closed portions 422 may be disposed between the openings 421 , and the openings 421 may be disposed between the closed portions 422 .

The sizes of the openings 421 and the closed portions 422 may be different from each other. Also, the sizes of the plurality of openings 421 may be different. Also, the sizes of the plurality of closed portions 422 may be different. For example, the sizes of the plurality of closed portions 422 may increase as the distance from the light source 300 increases.

The second reflective member 420 may improve the luminance of the display device. In detail, the light emitted from the light source 300 may have different intensities in a region where the light source 300 is disposed and a region where the light source 300 is not disposed. The luminance may become non-uniform in a region where the light source is not disposed.

Accordingly, by disposing the second reflective member 420 on the printed circuit board 200 , that is, the light source 300 , the light emitted from the light source 300 is reflected by the first reflective member 410 . and the second reflective member 420 may be recycled and emitted upward.

Accordingly, the amount of light in the region in which the light source 300 is disposed and the region in which the light source 300 is not disposed may be uniform, and thus the overall luminance may be uniform.

The first reflective member 410 may include a first reflective part 411 and a second reflective part 412 . The first reflection unit 411 and the second reflection unit 412 will be described in detail below.

The light conversion member 500 may be disposed on the reflective member 400 . In detail, the light conversion member 500 may be disposed on the second reflective member 420 .

2 and 3 , the light conversion member 500 may include a lower substrate 510 , an upper substrate 520 , a light conversion layer 530 , and a sealing part 540 .

The lower substrate 510 may be disposed under the light conversion layer 530 . The lower substrate 510 may be transparent and flexible. The lower substrate 510 may be in close contact with the lower surface of the light conversion layer 530 .

Examples of the material used for the lower substrate 510 include a transparent polymer such as polyethyleneterephthalate (PET).

The upper substrate 520 may be disposed on the light conversion layer 530 . The upper substrate 520 may be transparent and flexible. The upper substrate 520 may be in close contact with the upper surface of the light conversion layer 530 .

Examples of the material used for the upper substrate 520 include a transparent polymer such as polyethylene terephthalate.

The lower substrate 510 and the upper substrate 520 may be disposed on one surface and the other surface of the light conversion layer 530 . That is, the light conversion layer 530 may be disposed between the lower substrate 510 and the upper substrate 520 . The lower substrate 510 and the upper substrate 520 may support the light conversion layer 530 . The lower substrate 510 and the upper substrate 520 may protect the light conversion layer 530 from external physical impact. The lower substrate 510 and the upper substrate 520 may directly contact the light conversion layer 530 .

In addition, the lower substrate 510 and the upper substrate 520 may have low oxygen permeability and moisture permeability. Accordingly, the lower substrate 510 and the upper substrate 520 may protect the light conversion layer 530 from external chemical impacts such as moisture and/or oxygen.

The light conversion layer 530 may be interposed between the lower substrate 510 and the upper substrate 520 . The light conversion layer 530 may be in close contact with the upper surface of the lower substrate 510 and may be in close contact with the lower surface of the upper substrate 520 .

The light conversion layer 530 may include a matrix 531 and a plurality of light conversion particles 532 .

The matrix 531 may surround the light conversion particles 532 . That is, the matrix 531 may uniformly disperse the light conversion particles 532 therein. The matrix 531 may be formed of a polymer such as a silicone-based resin. The matrix 531 may be transparent. That is, the matrix 531 may be formed of a transparent polymer.

The matrix 531 may be disposed between the lower substrate 510 and the upper substrate 520 . The matrix 531 may be in close contact with the upper surface of the lower substrate 510 and the lower surface of the upper substrate 520 .

The light conversion particles 532 may be disposed between the lower substrate 510 and the upper substrate 520 . In detail, the light conversion particles 532 may be uniformly dispersed in the matrix 531 , and the matrix 531 may be disposed between the lower substrate 510 and the upper substrate 520 .

The light conversion particles 532 may convert a wavelength of light emitted from the light source 300 . The light conversion particles 532 may receive the light emitted from the light source 300 and convert the wavelength.

For example, the light conversion particles 532 may convert blue light emitted from the light source 300 into green light and red light. That is, some of the light conversion particles 532 convert the blue light into green light having a wavelength range between about 520 nm and about 560 nm, and some of the light conversion particles 532 convert the blue light. may be converted into red light having a wavelength range between about 630 nm and about 660 nm.

Alternatively, the light conversion particles 532 may convert the ultraviolet light emitted from the light source 300 into blue light, green light, and red light. That is, some of the light conversion particles 322 convert the ultraviolet light into blue light having a wavelength range of about 430 nm to about 470 nm, and some of the light conversion particles 532 convert the ultraviolet light to about It may be converted into green light having a wavelength range between 520 nm and about 560 nm. In addition, another portion of the light conversion particles 532 may convert the ultraviolet light into red light having a wavelength range of about 630 nm to about 660 nm.

That is, when the light source 300 is a blue light emitting diode that generates blue light, light conversion particles 532 that convert blue light into green light and red light, respectively, may be used. Alternatively, when the light source 300 is a UV light emitting diode generating ultraviolet rays, light conversion particles 532 that convert ultraviolet rays into blue light, green light, and red light, respectively, may be used.

In addition, when a phosphor for converting blue light into green light is disposed in a molding layer of a light emitting diode package constituting the light source, light conversion particles for converting blue light into red light may be disposed in the matrix. have.

Alternatively, when a phosphor for converting blue light into red light is disposed in a molding layer of a light emitting diode package constituting the light source, light conversion particles for converting blue light into green light may be disposed in the matrix. have.

In addition, when only quantum dots are used as light conversion particles, when the light source 300 is a blue light emitting diode that generates blue light, quantum dots that convert blue light into green light and red light, respectively, may be used.

Alternatively, in the case of using a mixture of quantum dots and phosphors as light conversion particles, when the light source 300 is a blue light emitting diode that generates blue light, a phosphor that converts blue light into green light and quantum dots that converts red light into red light Alternatively, quantum dots that convert blue light into green light and phosphors that convert red light may be used.

That is, the light conversion particle may include at least one of quantum dots and phosphors.

For example, the light conversion particles 532 may be a plurality of quantum dots (QDs). The quantum dots may include a core nanocrystal and a shell nanocrystal surrounding the core nanocrystal. In addition, the quantum dots may include an organic ligand bound to the shell nanocrystals. In addition, the quantum dots may include an organic coating layer surrounding the shell nanocrystals.

The shell nanocrystals may be formed in two or more layers. The shell nanocrystals are formed on the surface of the core nanocrystals. The quantum dots may convert the wavelength of light incident to the core nanocrystal to a longer wavelength through the shell nanocrystal forming the shell layer and increase light efficiency.

The quantum dots are, for example, CdS, CdO, CdSe, CdTe, Cd3P2, Cd3As2, ZnS, ZnO, ZnSe, ZnTe, MnS, MnO, MnSe, MnTe, MgO, MgS, MgSe, MgTe, CaO, CaS, CaSe, CaTe, SrO, SrS, SrSe, SrTe, BaO, BaS, BaSe, BaTE, HgO, HgS, HgSe, HgTe, Hg12, AgI, AgBr, Al2O3, Al2S3, Al2Se3, Al2Te3, Ga2O3, Ga2S3, Ga2Se3, In2O3, Ga2O3, Ga2S3, Ga2Se3, Ga2Se3, GaTe3 In2S3, In2Se3, In2Te3, SiO2, GeO2, SnO2, SnS, SnSe, SnTe, PbO, PbO2, PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaInP2, InN, InP, InAs, InSb, In2S3, In2Se3, TiO2, BP, Si, Ge, and may be a particle of a single-layer or multi-layer structure including one or more semiconductor crystals selected from the group consisting of, and combinations thereof.

The diameter of the quantum dots may be about 1 nm to 10 nm.

The wavelength of light emitted from the quantum dots can be adjusted according to the size of the quantum dots or the molar ratio of the molecular cluster compound and the nanoparticle precursor during the synthesis process. The organic ligand may include pyridine, mercapto alcohol, thiol, phosphine, and phosphine oxide. The organic ligand serves to stabilize unstable quantum dots after synthesis. After synthesis, a dangling bond is formed on the outside, and the quantum dot may become unstable because of the dangling bond. However, one end of the organic ligand is in an unbound state, and one end of the unbound organic ligand binds to a dangling bond, thereby stabilizing the quantum dot.

In particular, when the size of the quantum dot is smaller than the Bohr raidus of an exciton formed by electrons and holes excited by light, electricity, etc., a quantum confinement effect occurs and has sparse energy levels and an energy gap will change the size of In addition, the charge is localized in the quantum dot has high luminous efficiency.

Unlike general fluorescent dyes, the quantum dots have different fluorescence wavelengths depending on the size of the particles. That is, as the size of the particle becomes smaller, it emits light of a shorter wavelength, and by controlling the size of the particle, it is possible to emit fluorescence in the visible ray region of a desired wavelength. In addition, since the extinction coefficient is about 100 times to about 1000 times greater than that of a general dye and the quantum efficiency is also high, very strong fluorescence is generated.

The quantum dots may be synthesized by a chemical wet method. Here, the chemical wet method is a method of growing particles by adding a precursor material to an organic solvent, and the quantum dots may be synthesized by the chemical wet method.

In the preceding description, as an example of the light conversion particle, quantum dots have been described, but the embodiment is not limited thereto, and the light conversion particle may include a phosphor, or a phosphor and a quantum dot may be mixed and used.

Dispersibility improving particles may be further disposed in the matrix 531 .

The dispersibility enhancing particles may be transparent. The dispersibility enhancing particles may include an inorganic material. In more detail, examples of the material used as the dispersibility improving particles may include oxides such as silicon oxide. For example, silica particles may be used as the dispersibility improving particles.

The dispersibility enhancing particles may have a diameter of about 10 nm to about 10 μm.

The dispersibility improving particles may perform a function of improving the dispersibility of the light conversion particles in the host. In addition, the dispersibility enhancing particles may perform a scattering particle function to change the path of the incident light.

The sealing part 540 may be disposed on a side surface of the light conversion layer 530 . In detail, the sealing part 540 may cover the side surface of the light conversion layer 530 . In more detail, the sealing part 540 may be disposed on side surfaces of the lower substrate 510 and the upper substrate 520 . In more detail, the sealing part 540 may cover side surfaces of the lower substrate 510 and the upper substrate 520 .

In addition, the sealing part 540 may be adhered to the side surfaces of the light conversion layer 530 , the lower substrate 510 , and the upper substrate 520 . The sealing part 540 is in close contact with the side surfaces of the light conversion layer 530 , the lower substrate 510 , and the upper substrate 520 .

Accordingly, the sealing part 540 may seal the side surface of the light conversion layer 530 . That is, the sealing part 540 may be a protective part that protects the light conversion layer 530 from external chemical impact.

Referring to FIG. 4 , the light conversion member 500 may further include an inorganic passivation layer 550 . The inorganic passivation layer 550 may include a first inorganic passivation layer 551 and a second inorganic passivation layer 552 . In detail, the first inorganic protective layer 551 may be disposed on the lower surface of the lower substrate 510 , and the second inorganic protective layer 552 may be disposed on the upper surface of the upper substrate 520 .

Examples of the material used for the first inorganic passivation layer 551 and the second inorganic passivation layer 551 include silicon oxide.

Optical sheets such as the diffusion member 600 or the light collecting film 700 may be further included in the upper and/or lower portions of the light conversion member 500 , if necessary. In this case, the diffusion member 600 and the light collection film 700 diffuse and condense the light that has passed through the second reflection member 420 and is emitted to the outside, thereby improving the luminance distribution of the backlight unit and improving the luminance. it is to make

In FIG. 1 , it is described that the diffusion member 600 is disposed under the light conversion member 500 and the light collection film 700 is disposed above the light conversion member 500 , but the present invention is not limited thereto. it is not For example, both the diffusion member and the light collecting film may be disposed on the light conversion member 500 .

In addition, although it is illustrated that the diffusion member and the light collecting film are provided one by one in the drawings, the present invention is not limited thereto, and one or more diffusion members and the light collecting film may be applied. Meanwhile, as the light collecting film, a prism sheet, a lenticular sheet, DBEF, or the like may be used.

Meanwhile, as the light collecting film, a round prism film as shown in FIG. 5 may be used. The round prism film is a film in which the right angle portion of the prism film is rounded, and when it is used, light is diffused in the right angle portion of the prism film, so that the color difference can be improved compared to the case where the prism film is used.

6 and 7 are cross-sectional views illustrating a display device according to an exemplary embodiment.

6 and 7 , the first reflective member 410 disposed on the printed circuit board 200 may include a first reflective part 411 and a second reflective part 412 . .

The first reflector 411 may be disposed on the printed circuit board 200 . The first reflector 411 may be disposed in contact with the printed circuit board 200 . The first reflector 411 may have a hole formed in a region corresponding to the light source 300 .

The second reflector 412 may extend in a direction different from that of the first reflector 411 . In detail, the second reflective part 412 may be connected to the first reflective part 411 and may be bent and extended from the first reflective part 411 .

In detail, the second reflective part 412 may extend by bending at one end and the other end of the first reflective part 411 . The second reflector 412 may extend in the liquid crystal panel direction.

Referring to FIG. 6 , an angle between the first reflecting unit 412 and the second reflecting unit 412 may be a right angle. That is, the second reflection part 412 may extend in the same direction as the side surface of the bottom cover 100 .

Alternatively, referring to FIG. 7 , the angle formed between the first reflecting unit 412 and the second reflecting unit 412 may be an obtuse angle. That is, the second reflection unit 412 may extend in a direction different from that of the side surface of the bottom cover 100 .

The second reflection unit 412 may be disposed between the side surface of the bottom cover 100 and the light conversion member 500 . In detail, the second reflection unit 412 may be disposed between the side surface of the bottom cover and the light conversion member 500 , the diffusion member 600 and the light collection film 700 .

In addition, the second reflection unit 412 may be disposed to be spaced apart from the side surface of the bottom cover 100 . Also, the second reflection unit 412 may be disposed to be spaced apart from at least one of the light conversion member 500 , the diffusion member 600 , and the light collection film 700 .

One end of the second reflecting unit 412 is connected to the first reflecting unit 411 , and the other end of the second reflecting unit 412 is formed from the lower surface of the diffusion member 600 . It may extend to any one of the distances to the upper surface. That is, the length of the second reflective part 412 is the distance from the connection point with the first reflective part 411 to the lower surface of the diffusion member 600 to the length of the light collecting film at the connection point with the first reflective part 411 . It may be the distance to the upper surface of 700 .

The length of the second reflection unit 412 may be appropriately controlled within the above range in consideration of the luminance and color non-uniformity of the light source 300 . In addition, the length of the second reflection unit 412 connected from one end of the first reflection unit 411 and the length of the second reflection unit connected from the other end of the first reflection unit 411 are similar to each other, or or different from each other. The lengths of the second reflection units 412 connected at one end and the other end of the first reflection unit 411 may be appropriately controlled within the above range in consideration of the luminance and color non-uniformity of the light source 300 . .

The first reflective part 411 and the second reflective part 412 may be integrally formed. That is, by bending one end and the other end of the first reflective member 410 , the second reflective part 412 bent from the first reflective part 411 may be formed.

Alternatively, the first reflection unit 411 and the second reflection unit 412 may be separated. That is, by arranging the first reflecting unit 411 first, and then connecting the second reflecting unit to one end and the other end of the first reflecting unit 411 , the first reflecting unit 411 is bent from the first reflecting unit 411 . Two reflection units 412 may be formed.

The second reflector 412 transmits light passing between the side surface of the bottom cover 100 and the light conversion member 500 among the light emitted from the light source 300 to the inside of the bottom cover 100 . can reflect.

In addition, light reflected inside the bottom cover 100 by the second reflection unit 412 may pass through the light conversion member 500 .

Accordingly, it is possible to prevent a decrease in color uniformity of light due to the light passing through the light conversion member in the edge region of the backlight unit.

Accordingly, the color of the light emitted from the light source 300 and incident in the direction of the liquid crystal panel 20 can be made uniform as a whole, thereby realizing a uniform screen.

8 and 9 are cross-sectional views illustrating a display device according to another exemplary embodiment.

8 and 9 , the display device according to another exemplary embodiment may further include a second light conversion member 520 . In detail, the light conversion member 500 includes a first light conversion member 510 and the second reflection unit 421 disposed on at least one of one surface and the other surface of the diffusion member 600 , and the second light conversion member 500 . A second light conversion member 520 disposed between at least one of the first light conversion member 510 and the diffusion member 600 may be included.

8 and 9 , the second light conversion member 520 may be disposed between the first reflection unit 410 and the first light conversion member 500 and the diffusion member 600 . . In detail, the second light conversion member 520 may be disposed between the second reflection unit 412 of the first reflection member 410 and the first light conversion member 510 and the diffusion member 600 . can

That is, the second light conversion member 520 is bent from the first light conversion member 510 and extends, and the second reflection part 412 of the first reflection member 410 and the light conversion member ( 500 ) and the diffusion member 600 .

Referring to FIG. 8 , an angle between the first reflecting unit 412 and the second reflecting unit 412 may be a right angle. That is, the second reflection part 412 may extend in the same direction as the side surface of the bottom cover 100 .

In addition, the second light conversion member 520 is disposed between the second reflector 412 , the first light conversion member 510 and the diffusion member 600 , and the second light conversion member 520 . ) may be disposed in contact with an inner surface of the second reflection unit 412 , and an outer surface of the first light conversion member 510 and the diffusion member 600 .

The second light conversion member 520 includes an inner surface of the second reflection unit 412 through an adhesive layer between the second reflection unit 412 and the light conversion member 500 and the diffusion member 600, Between the second reflecting unit 412 and the first light converting member 510 and the diffusing member 600 being adhered to the outer surfaces of the light conversion member 500 and the diffusion member 600 or without an adhesive layer It can be interposed in the fit-coupled.

Alternatively, referring to FIG. 9 , the angle formed between the first reflecting unit 412 and the second reflecting unit 412 may be an obtuse angle. That is, the second reflection unit 412 may extend in a direction different from that of the side surface of the bottom cover 100 .

In addition, the second light conversion member 520 is disposed between the second reflector 412 , the first light conversion member 510 and the diffusion member 600 , and the second light conversion member 520 . ) may be disposed in contact with an inner surface of the second reflection unit 412 , and an outer surface of the first light conversion member 510 and the diffusion member 600 .

Since the first reflecting part 411 and the second reflecting part 412 have an obtuse angle, the second light conversion member 520 is in partial contact with the second reflecting part 412, Partially spaced apart may be arranged.

The second light conversion member 520 includes an inner surface of the second reflection unit 412 through an adhesive layer between the second reflection unit 412 and the light conversion member 500 and the diffusion member 600, Adhesive to the outer surfaces of the light conversion member 500 and the diffusion member 600 , or interposed between the second reflection unit 412 and the light conversion member 500 and the diffusion member 600 without an adhesive layer and can be fitted together.

The first light conversion member 510 and the second light conversion member 520 may be integrally formed. That is, by bending one end and the other end of the light conversion member 500 , the first light conversion member 510 and the second light conversion member 520 are bent and extended from the first light conversion member 510 . can form.

In the display device according to the embodiment, by disposing the second light conversion member in the edge area, light emitted from the light source and passing through the edge area and/or light emitted from the light source and reflected by the second reflection unit and passed through the edge area The wavelength of light may be converted by the second light conversion member.

Accordingly, since the edge region is irradiated in the direction of the liquid crystal panel without passing through the light conversion member, it is possible to prevent the blue color from darkening compared to other regions, and thus the overall color uniformity can be improved.

The first light conversion member 510 may include first light conversion particles. Also, the second light conversion member 520 may include second light conversion particles.

The first light conversion particle and the second light conversion particle may include a light conversion material of at least one of quantum dots and phosphors.

Concentrations of the first light conversion particle and the second light conversion particle may be different. That is, the weight % of the first light conversion particles dispersed in the matrix of the first light conversion member 510 and the weight% of the second light conversion particles dispersed in the matrix of the second light conversion member 520 . Concentrations may be different.

In detail, the concentration of the second light conversion particles may be greater than the concentration of the first light conversion particles. Accordingly, a color difference between the light emitted from the light source and passing through the first light conversion member and the light passing through the second light conversion member may be reduced.

10 to 12 are cross-sectional views illustrating still another exemplary embodiment of a display device according to an exemplary embodiment.

10 and 12 , in the display device according to another exemplary embodiment, the concentration of the light conversion particle of the light conversion member may be different depending on the location of the light conversion member.

The light conversion layer 530 may include a central area CA and an edge area OA. The central area CA and the edge area OA may be disposed adjacent to each other. Also, the edge area OA may surround the central area CA. The width W of the edge area OA may be about 15 mm or less. In detail, the width of the edge area OA may be about 1 mm to about 15 mm. In more detail, the width of the edge area OA may be about 5 mm to about 15 mm.

The light conversion layer 530 may include a matrix 531 and light conversion particles 532 . The edge area OA may include the light conversion particles 532 by a first concentration (wt%). In addition, the central region CA may include the light conversion particle 532 as much as a second concentration (weight %).

Here, the first concentration and the second concentration may mean a weight % of the light conversion particles disposed in the matrix.

The first concentration and the second concentration may be different. In detail, the first concentration may be greater than the second concentration.

The first concentration may be greater than the second concentration by about 5% to about 50% by weight. When the first concentration is greater than about 5% by weight or greater than about 50% by weight compared to the second concentration, color non-uniformity may occur in the edge region and the central region of the light conversion layer, resulting in deterioration of quality have.

That is, the display device according to the embodiment may reduce the color difference between the edge region and the center region by differentiating the light conversion particle concentrations in the edge region and the central region of the light conversion layer.

Referring to FIG. 13 , the distance between the light sources 300 mounted on the printed circuit board 200 may be different for each location.

In detail, the distance between the light sources 300 may become smaller as they extend from the central area CA to the edge area OA. That is, the light sources 300 may be more densely arranged as they extend from the central area CA to the edge area OA. In more detail, the light sources disposed in the edge area OA may be spaced apart from each other by a first interval, and the light sources disposed in the central area CA may be disposed spaced apart from each other at a second interval. Also, the first interval may be smaller than the second interval.

Accordingly, by arranging the light sources more densely in the edge area OA, it is possible to prevent a decrease in luminance in the edge area OA having a high concentration of the light conversion layer.

14 and 15 are cross-sectional views illustrating a display device according to another exemplary embodiment.

14 and 15 , the second light conversion member 520 may be disposed to be spaced apart from the light source 300 .

In detail, the second light conversion member 520 may be disposed on the first reflective member 410 . In more detail, the second light conversion member 520 may be disposed on the first reflection unit 411 of the first reflection member 410 .

The second light conversion member 520 may be disposed at an end of the first reflector 411 . For example, the second light conversion member 520 may be disposed at one end and the other end of the first reflector 411 .

The second light conversion member 520 may be disposed in contact with the first reflection unit 411 . Also, the second light conversion member 520 may be disposed to be in contact with or spaced apart from the second reflection unit 412 .

The second light conversion member 520 converts the wavelength of the light emitted from the light source 300 is reflected from the upper portion and returned back to the first reflector 411 , and then returns the light toward the edge region. can reflect.

Alternatively, the second light conversion member 520 may convert the wavelength of the light emitted laterally from the light source 300 to emit the light toward the edge region.

Accordingly, since the edge region is irradiated in the direction of the liquid crystal panel without passing through the light conversion member, it is possible to prevent the blue color from darkening compared to other regions, and thus the overall color uniformity can be improved.

The liquid crystal panel 20 may be disposed on the optical sheets. Also, the liquid crystal panel 20 may be disposed on the panel guide 23 . The liquid crystal panel 20 may be guided by the panel guide 23 .

The liquid crystal panel 20 may display an image by adjusting the intensity of light passing therethrough. That is, the liquid crystal panel 20 is a display panel that displays an image by using the light emitted from the backlight unit 10 . The liquid crystal panel 20 may include a TFT substrate 21 , a color filter substrate 22 , and a liquid crystal layer interposed between the two substrates. Also, the liquid crystal panel 20 may include polarizing filters.

Although not shown in detail in the drawings, if the TFT substrate 21 and the color filter substrate 22 are described in detail, the TFT substrate 21 has a plurality of gate lines and data lines intersecting to define a pixel, and each intersection A thin film transistor (TFT) is provided in each region, and may be connected to a pixel electrode mounted in each pixel in a one-to-one correspondence. The color filter substrate 22 includes color filters of R, G, and B colors corresponding to each pixel, a black matrix surrounding each of them and covering gate lines, data lines, thin film transistors, and the like, and a common electrode covering all of them. may include

A driving PCB 25 for supplying driving signals to a gate line and a data line may be provided at an edge of the liquid crystal panel 20 .

The driving PCB 25 may be electrically connected to the liquid crystal panel 20 by a chip on film (COF) 24 . Here, the COF 24 may be changed to a Tape Carrier Package (TCP).

Hereinafter, the present invention will be described in more detail through Examples and Comparative Examples. These embodiments are merely presented as examples in order to explain the present invention in more detail. Therefore, the present invention is not limited to these examples.

Example 1

A printed circuit board was placed on the bottom cover, and a light source was mounted on the printed circuit board, and then a reflective sheet having a hole formed in an area corresponding to the light source was placed on the printed circuit board.

Then, another reflective sheet, a diffusion sheet, a quantum dot layer, and a light collecting film were disposed on the light source to prepare a backlight unit, and then a liquid crystal panel was disposed on the backlight unit to manufacture a display device.

In addition, the reflective sheet was bent in the direction of the liquid crystal panel so that the reflective sheet was disposed between the bottom cover and the quantum dot layer.

Then, the color difference (dCy) between the central region and the edge region was measured.

Example 2

After manufacturing the backlight unit in the same manner as in Example 1, except that another quantum dot layer was further disposed between the inner surface of the bottom cover and the quantum dot layer and/or the diffusion sheet, the color of the central region and the edge region The difference (dCy) was measured.

comparative example

A backlight unit was manufactured in the same manner as in Example 1 except that the reflective sheet was not bent in the direction of the liquid crystal panel, and then the color difference (dCy) between the center region and the edge region was measured.

Color difference between center and edge areas (dCy) Example 1 0.01 practice 2 0.005 comparative example 0.02

Referring to Table 1, it can be seen that the color difference between Examples 1 and 2 is 0.01 or less. On the other hand, in the case of the comparative example, it can be seen that the color difference exceeds 0.01, so that the color difference is visually recognized from the outside.

That is, it can be seen that the display devices according to the embodiments can reduce color differences compared to the comparative examples.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In the above, the embodiment has been mainly described, but this is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (21)

a plurality of light sources mounted on the printed circuit board;
a reflective member disposed on the printed circuit board;
a light conversion member disposed on the light source; and
a diffusion member disposed above or below the light conversion member;
The reflective member is
a first reflector disposed in contact with the printed circuit board; and
and a second reflective part bent and extended from the first reflective part,
The light conversion member,
a first light conversion member disposed on at least one of one surface and the other surface of the diffusion member; and
a second light conversion member disposed between the second reflection unit and at least one of the first light conversion member and the diffusion member;
The first light conversion member includes first light conversion particles,
The second light conversion member includes second light conversion particles,
A concentration (% by weight) of the second light conversion particles is greater than a concentration (% by weight) of the first light conversion particles. The method of claim 1,
The second reflection unit is disposed to be spaced apart from the light conversion member. The method of claim 1,
The second reflection unit is disposed to be spaced apart from at least one of the light conversion member and the diffusion member. The method of claim 1,
The first reflector and the second reflector are integrally formed in a backlight unit. The method of claim 1,
The first light conversion member and the second light conversion member are integrally formed in a backlight unit. 6. The method of claim 5,
The second light conversion member is bent from the first light conversion member and extends. The method of claim 1,
The reflective member may include a first reflective member disposed on the printed circuit board; and
a second reflective member disposed on the first reflective member;
The second reflective member includes an opening and a closed part. a plurality of light sources mounted on the printed circuit board;
a reflective member disposed on the printed circuit board; and
Including a light conversion member disposed on the upper portion of the light source,
The reflective member is
a first reflector disposed in contact with the printed circuit board; and
and a second reflective part bent and extended from the first reflective part,
The light conversion member,
lower substrate;
an upper substrate on the lower substrate; and
a light conversion layer between the lower substrate and the upper substrate;
The light conversion layer may include a matrix; and light converting particles disposed within the matrix;
The light conversion layer may include a central region; and an edge region surrounding the central region;
The center area and the edge area are areas for displaying a screen,
The edge region comprises light conversion particles in a first concentration (wt%),
The central region comprises light conversion particles in a second concentration (wt%),
The first concentration is greater than the second concentration of the backlight unit. 9. The method of claim 8,
The difference between the first concentration and the second concentration is 5 wt% to 50 wt% of the backlight unit. 9. The method of claim 8,
The width of the edge region of the backlight unit is 15 mm or less. 9. The method of claim 8,
The distance between the light sources becomes smaller as the distance between the light sources increases from the central area to the edge area of the shopping mall. 9. The method of claim 8,
In the edge region, the light sources are spaced apart by a first interval,
In the central region, the light sources are spaced apart at a second interval,
The first interval is smaller than the second interval of the backlight unit. 9. The method of claim 8,
The light conversion particle is a backlight unit including a quantum dot (quantum dot). The method of claim 1,
An angle between the first reflector and the second reflector is 90° or more. The backlight unit according to any one of claims 1 to 14; and
and a liquid crystal panel on the backlight unit. delete delete delete delete delete delete

Images