KR102227324B1 - Optical transforming sheet, backlight unit and liquid crystral display device having the same - Google Patents

Abstract

The present invention discloses a light conversion sheet, a backlight unit having the same, and a liquid crystal display device. The light conversion sheet of the disclosed invention includes: a first light emitting sheet including a first substrate and a first light conversion layer disposed on the first substrate; A second light emitting sheet including a second substrate and a second light conversion layer disposed on the second substrate; First and second quantum dots and beads included in the first and second photoconversion layers; And an optical adhesive film disposed between the first and second light conversion layers so that the first and second light emitting sheets are bonded together.
The light conversion sheet of the present invention, a backlight unit having the same, and a liquid crystal display device, separates the light conversion sheet into a light conversion layer having a high refractive index and a light conversion layer having a low refractive index by optical patterns, so that the light efficiency by recycling light It has the effect of improving.

Description

Light conversion sheet, backlight unit and liquid crystal display device having the same {OPTICAL TRANSFORMING SHEET, BACKLIGHT UNIT AND LIQUID CRYSTRAL DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a liquid crystal display device, and more particularly, a light conversion sheet in which optical patterns are formed inside a light conversion sheet including quantum dots to improve light emission characteristics of the light conversion sheet, and a backlight unit having the same And a liquid crystal display device.

Recently, a liquid crystal display device has been in the spotlight as a next-generation high-tech display device with low power consumption, good portability, and high added value.

Among these liquid crystal displays, the active matrix liquid crystal display equipped with a thin film transistor, which is a switching element that can control the voltage on and off for each pixel, is the most noticeable due to its excellent resolution and video realization ability. Are receiving.

In general, a liquid crystal display device forms an array substrate and a color filter substrate, respectively, through an array substrate manufacturing process for forming a thin film transistor and a pixel electrode, and a color filter substrate manufacturing process for forming a color filter and a common electrode, and between the two substrates. It is completed through a cell process through a liquid crystal.

However, since the liquid crystal display does not have its own light-emitting element, a separate light source is required to display the difference in transmittance as an image, and for this purpose, a backlight unit with a built-in light source is arranged on the back of the liquid crystal display panel. do.

Such a backlight unit is divided into a direct type and an edge type according to the position of the light source. The direct type backlight unit places the light source under the liquid crystal display panel to directly direct light emitted from the light source. The light guide plate is disposed under the LCD panel, and the light source is disposed on at least one side of the light guide plate, so that the light guide is emitted from the light source using refraction and reflection from the light guide plate. It is a method of indirectly supplying light to the liquid crystal display panel.

Here, as the light source of the backlight unit, a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL) has been widely used. According to the trend of lightweighting, light emitting diodes (LEDs), which have advantages in power consumption, weight, and brightness, are replacing fluorescent lamps.

In addition, a plurality of optical sheets are disposed between the light guide plate and the liquid crystal display panel of the backlight unit, and recently, a light conversion sheet including a quantum dot is additionally disposed to improve the transmittance of light generated from a light source. .

The light conversion sheet including the quantum dots is formed by mixing quantum dots, inorganic phosphors, or organic phosphors together with a light emitting auxiliary material to absorb light emitted from the light guide plate and then emit light.

1 is a view showing a structure of a light conversion sheet according to the prior art, and FIG. 2 is a view showing light emission characteristics of the light conversion sheet of FIG. 1.

1 and 2, the photoconversion sheet 10 according to the prior art is provided between the first and second substrates 10a and 10b, and the first and second substrates 10a and 10b. It includes a light conversion layer 20. A first barrier layer 11 is formed between the first substrate 10a and the light conversion layer 20, and a second barrier layer 12 is formed between the second substrate 10b and the light conversion layer 20. Can be placed.

When the light source is a blue light source, the light conversion layer 20 is formed by mixing red quantum dots Q1 or green quantum dots Q2 in a resin having a refractive index.

The light conversion sheet 10 is disposed between the light guide plate and the optical sheets of a backlight unit using a blue LED as a light source, and the blue light traveling through the light guide plate is a red quantum dot ( It is converted into red light and green light by Q1) and green quantum dots (Q2). Therefore, in the light conversion sheet 10, blue light, red light, and green light are mixed to implement white light.

However, as shown in the drawing, the light L passing through the light conversion layer 20 generates a total reflection area due to the difference in refractive index between the light conversion layer 20 and the second substrate 10b. There is a problem in that the leaking light L that cannot proceed to the top of 10) is generated.

In general, when the refractive index of the light conversion layer 20 is 1.63, light traveling from the light conversion layer 20 toward the second substrate 10b to 37.8° or more is totally reflected, resulting in light loss.

As shown in FIG. 2, the first light L1 that passes through the second barrier layer 12 and the second substrate 10b of the light conversion sheet 10 and proceeds upward and does not proceed upward due to total reflection. It can be seen that the second light L2 trapped in the light conversion sheet 10 is present.

As described above, in the conventional light conversion sheet including quantum dots, there is a problem in that the light efficiency is deteriorated due to the leakage light in the side area and the leakage light due to total reflection.

An object of the present invention is to provide a light conversion sheet having improved light efficiency by arranging optical patterns inside the light conversion sheet, a backlight unit having the same, and a liquid crystal display device.

In addition, the present invention is a light conversion sheet that improves light efficiency by recycling light by separating the light conversion sheet into a light conversion layer having a high refractive index and a light conversion layer having a low refractive index by optical patterns, and a backlight unit having the same And to provide a liquid crystal display device is another object.

The light conversion sheet of the present invention for solving the problems of the prior art as described above includes: a first light emitting sheet including a first substrate and a first light conversion layer disposed on the first substrate; A second light emitting sheet including a second substrate and a second light conversion layer disposed on the second substrate; First and second quantum dots and beads included in the first and second photoconversion layers; And an optical adhesive film disposed between the first and second light conversion layers so that the first and second light emitting sheets are bonded together.

In addition, a backlight unit according to another embodiment of the present invention includes a light source; A light guide plate that converts the light source into surface light; A light conversion sheet disposed on the light guide plate; An optical sheet disposed on the light conversion sheet; And a reflective plate disposed under the light guide plate, wherein the light conversion sheet includes a first substrate, a first light-emitting sheet including a first light conversion layer disposed on the first substrate, a second substrate, and the A second light emitting sheet including a second light conversion layer disposed on a second substrate, first and second quantum dots and beads included in the first and second light conversion layers, and the first and second light emission And an optical adhesive film disposed between the first and second light conversion layers so that the sheets are bonded together.

In addition, a liquid crystal display device according to another embodiment of the present invention includes a liquid crystal display panel; And a light source to supply surface light to the liquid crystal display panel, a light guide plate for converting light incident from the light source into a surface light source, a light conversion sheet disposed on the light guide plate, and an optical sheet disposed on the light conversion sheet. , A backlight unit having a reflective plate disposed under the light guide plate, wherein the light conversion sheet includes a first substrate, a first light-emitting sheet including a first light conversion layer disposed on the first substrate, and a first light-emitting sheet A second light emitting sheet including a second substrate and a second light conversion layer disposed on the second substrate, first and second quantum dots and beads included in the first and second light conversion layers, and the first And an optical adhesive film disposed between the first and second light conversion layers so that the second light emitting sheets are bonded together.

The light conversion sheet of the present invention, a backlight unit and a liquid crystal display having the same, has an effect of improving light efficiency by arranging optical patterns inside the light conversion sheet.

In addition, the light conversion sheet of the present invention, a backlight unit having the same, and a liquid crystal display device, separate the light conversion sheet into a light conversion layer having a high refractive index and a light conversion layer having a low refractive index by optical patterns. There is an effect of improving the light efficiency.

1 is a view showing the structure of a light conversion sheet according to the prior art.
FIG. 2 is a diagram showing light emission characteristics of the light conversion sheet of FIG. 1.
3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
4 is a diagram showing the structure of a light conversion sheet used in the liquid crystal display device of the present invention.
5 is a view showing light emission characteristics of the light conversion sheet of FIG. 4.
6 and 7 are views showing the structure of a light conversion sheet according to another embodiment of the present invention.
8 is a diagram showing light emission characteristics of the light conversion sheet having the structure of FIG. 7.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the 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 a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, 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. The same reference numerals refer to the same elements throughout the specification. In addition, in describing the present invention, when 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'include','have', and'consist of' mentioned in the present specification are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise.

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

In the case of a description of the positional relationship, for example, if the positional relationship of two parts is described as'upper','upper of','lower of','next to','right' Or, unless'direct' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example,'after','following','after','before', etc. It may also include cases that are not continuous unless' is used.

First, second, etc. are used to describe various elements, but these elements 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 a second component within the technical idea of the present invention.

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or can be implemented together in an association relationship. May be.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the drawings, the size and thickness of the device may be exaggerated for convenience. The same reference numbers throughout the specification indicate the same elements.

3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the liquid crystal display 100 includes a support main 130 and a lower cover for modularizing the liquid crystal display panel 110 and the backlight unit 120, and the liquid crystal display panel 110 and the backlight unit 120. (150) And consists of a top cover (140).

Looking at each of these in more detail, the liquid crystal display panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130, and the lower cover 150, and the top cover 140 is a liquid crystal display. In the shape of a rectangular frame whose cross section is bent in a “b” shape so as to cover the top and side edges of the display panel 110, the top cover 140 is opened to display an image implemented in the liquid crystal display panel 110. Make up.

In addition, the lower cover 150, which is the basis for assembling the entire liquid crystal display device by seating the liquid crystal display panel 110 and the backlight unit 120, is a horizontal surface 151 that is in close contact with the rear surface of the backlight unit 120. ) And a side surface 153 whose edges are vertically bent upward.

In addition, a support main 130 in the shape of a square frame, which is seated on the lower cover 150 and has an open edge around the edge of the liquid crystal display panel 110 and the backlight unit 120, is provided with the top cover 140 and the lower part. It is combined with the cover 150.

At this time, the top cover 140 may be referred to as a case top or a top case, the support main 130 may be referred to as a guide panel, a main support, or a mold frame, and the lower cover 150 is referred to as a bottom cover or a cover bottom. It is also said to be.

In addition, the liquid crystal display panel 110 plays a key role in image display, and includes an array substrate 112 and a color filter substrate 114 bonded to each other with a liquid crystal layer therebetween.

In this case, although not shown in the drawing under the premise of the active matrix method, a plurality of gate lines and data lines cross each other to define a pixel on the inner surface of the array substrate 112, which is usually called a lower substrate or a thin film transistor substrate. A thin film transistor (TFT) is provided at each intersection point and is connected to a transparent pixel electrode formed in each pixel in a one-to-one correspondence.

And, as an example corresponding to each pixel, a color filter of red (R), green (G), and blue (B) colors and each of them are covered on the inner surface of the color filter substrate 114 called the upper substrate. A black matrix is provided to cover gate lines, data lines, and thin film transistors. In addition, red (R), green (G), and blue (B) color filters and transparent common electrodes covering the black matrix are provided.

However, in the case of an IPS (In-Plane Switching) mode or FFS (Fringe Field Switching) mode liquid crystal display device, a pixel electrode and a common electrode may be disposed in the array substrate 112.

Further, polarizing plates (not shown) that selectively transmit only specific light are attached to the outer surfaces of the array substrate and the color filter substrates 112 and 114, respectively.

The printed circuit board 117 is connected through a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) along at least one edge of the liquid crystal display panel 110, The side surface of the support main 130 or the rear surface of the lower cover 150 is properly folded and adhered.

In the liquid crystal display panel 110, when the thin film transistor selected for each gate line is turned on by the on/off signal of the gate driving circuit, the signal voltage of the data driving circuit is transmitted to the corresponding pixel electrode through the data line. The arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, indicating a difference in transmittance.

In addition, the liquid crystal display according to the present invention is provided with a backlight unit 120 that supplies light from the rear surface of the liquid crystal display panel 110 so that a difference in transmittance of the liquid crystal display panel 110 is expressed to the outside.

The backlight unit 120 includes an LED assembly 129, a white or silver reflector 125, a light guide plate 123 mounted on the reflector 125, an optical sheet 210 interposed thereon, and the optical And a light conversion sheet 300 disposed between the sheet 210 and the light guide plate 123. The light conversion sheet 300 is formed in a rectangular plate structure similar to the light guide plate 123 or the optical sheet 210, and as described in FIGS. 4, 6 and 7 inside to improve light emission efficiency, Optical patterns are formed.

In addition, the light conversion sheet 300 is implemented as separate first and second light emitting sheets, and the light conversion layers disposed inside the first and second light emitting sheets have a specific pattern structure (for example, a prism structure). , A rectangular structure, a lens structure, a cone structure, a pyramid structure, etc.) to minimize the occurrence of total reflection in the light conversion sheet 300 to improve light emission efficiency.

In addition, light efficiency is improved by different refractive indices of the light conversion layers disposed on the first and second light emitting sheets of the light conversion sheet 300 of the present invention. A detailed description will be given in FIGS. 4 to 8.

The LED assembly 129 is located on one side of the light guide plate 123 to face the light incident surface of the light guide plate 123, and such an LED assembly 129 includes a plurality of LEDs 129a and a plurality of LEDs 129a. It includes a PCB (129b) to be mounted spaced apart.

The LED assembly 129 has a top view type in which light emitted from a plurality of LEDs 129a is perpendicular to the PCB 129b.

At this time, the LED 129a is made of a blue LED that emits blue light having a wavelength of about 430 nm to 450 nm in order to improve luminous efficiency and luminance.

In addition, the backlight unit 120 of the present invention uses a blue LED 129a, and the light conversion sheet 300 includes a green and red quantum dot, a green phosphor, and a red ( Red) quantum dots or a light conversion layer composed of red phosphors and green quantum dots may be disposed.

In addition, when a mold or lens containing a red phosphor is used for the blue LED 129a, or a mixture of the blue LED 129a and the red LED is used, the light conversion sheet 300 has a green quantum dot or a green ( Green) It can be formed in a structure containing a phosphor.

In addition, when a mold or a lens including a green phosphor is used for the blue LED 129a, or a blue (LED 129a and green LED are mixed and used, the light conversion sheet 300 is red ( Red) It may be formed in a structure including a quantum dot or a red phosphor.

The reflective plate 125 is located on the rear surface of the light guide plate 123 and reflects the light passing through the rear surface of the light guide plate 123 toward the liquid crystal display panel 110 to improve the luminance of light.

The optical sheet 210 disposed above the light guide plate 123, that is, on the light emitting sheet 300, includes a diffusion sheet and at least one light collecting sheet, and the light guide plate 123 and the light conversion sheet 300 The light that has passed through is diffused or condensed so that a more uniform surface light source is incident on the liquid crystal display panel 110.

FIG. 4 is a view showing the structure of a light conversion sheet used in the liquid crystal display device of the present invention, and FIG. 5 is a view showing light emission characteristics of the light conversion sheet of FIG. 4.

4 and 5, the light conversion sheet 300 of the present invention includes a first light emitting sheet 320 and a second light emitting sheet 310.

The first light emitting sheet 320 is composed of a first barrier layer 312 and a first light conversion layer 313 on a first substrate 311 made of a transparent insulating material (PET, etc.), and the second light emission The sheet 310 includes a second barrier layer 302 and a second photoconversion layer 303 on a second substrate 301 made of a transparent insulating material. The first and second barrier layers 312 and 302 may be formed of an inorganic material.

The first and second light conversion layers 313 and 303 disposed on the first light emitting sheet 320 and the second light emitting sheet 310 are implemented in a prism pattern. The light emitting sheet 310 was interlocked and attached by an optical adhesive film 330 (Optical Clear Resin). Therefore, the cross-sectional structure of the optical adhesive film is formed in a pattern in which prismatic peaks and valleys are continuous.

Further, although not shown in the drawings, a light diffusion layer including a plurality of light diffusing agents such as beads may be coated on the outer surface of the first light emitting sheet 320 and the outer surface of the second light emitting sheet 310. .

The first and second light conversion layers 313 and 303 may include first and second quantum dots (Q1, Q2) and beads (B). The first and second quantum dots (Q1, Q2) may be made of semiconductors, alloys, or mixtures of groups Ⅱ-VI, Ⅱ-Ⅲ, Ⅲ-V, Ⅲ-VI, VI-IV, and Ⅳ of the periodic table. have.

That is, when the first and second quantum dots (Q1, Q2) are made of Group II-VI of the periodic table, one or two or more of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe Materials can be mixed.

And in the case of group III-V, any one of InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe, or two or more materials may be mixed. .

In addition, in the case of group VI-IV, any one of PbSe, PbTe, PbS, PbSnTe, and Tl2SnTe5, or two or more substances may be mixed.

The first and second quantum dots Q1 and Q2 may be red quantum dots that generate red light and green quantum dots that generate green light, respectively.

In addition, the first and second photoconversion layers 313 and 303 may be formed by mixing any one of the first and second quantum dots Q1 and Q2 and a red or green phosphor corresponding thereto.

In addition, the diameters of the first and second quantum dots Q1 and Q2 may have an average diameter of 0.5 nm to 30 nm, and resin used for the first and second photoconversion layers 313 and 303 ) Is poly(methyl(meth)acrylate) (poly(methyl(meth)acrylate)), poly(ethylene glycol dimethacrylate) (poly(ethylene glycol dimethacrylate), polyvinyl acetate), poly(dimethacrylate) A material selected from the group consisting of vinyl benzene), poly(thioether), silica, polyepoxide, and combinations thereof may be used.

As described above, the diameter range of the quantum dots may be selectively applied to implement various color gamuts. This is because quantum dots have different luminescence characteristics and wavelengths according to their diameters, and thus can be adjusted according to the requested color purity. For example, it is possible to increase the color reproduction rate by adjusting the half width of the emitted light wavelength according to the diameter of the quantum dot. In general, light with a narrow half-width has better color purity, resulting in better color reproduction.

The resin materials of the light conversion layer are selected materials to prevent the quantum dots included in the light conversion layer from being damaged by moisture or other materials.

In addition, it is preferable to select the resin of the light conversion layer among the resin materials in order to increase light emission efficiency by having different refractive indices of the first and second light conversion layers 313 and 303 from each other.

In addition, it is preferable that the resin refractive index of the second light conversion layer 303 is greater than the resin refractive index of the first light conversion layer 313. This is to improve light emission efficiency by preventing total reflection from occurring in the second light-emitting sheet 310 of light traveling from the first light-emitting sheet 320.

In addition, although not shown in the drawings, a plurality of beads may be included in the optical adhesive film 330 to which the first light emitting sheet 320 and the second light emitting sheet 310 are attached.

The content of the beads is selectively applied in the range of 0% to 50%. That is, the optical adhesive film 330 does not include beads and is used only as an adhesive function, or a plurality of beads are included so that light refraction or light reflection occurs even in the optical adhesive film 330 area, thereby improving light efficiency. .

Referring to FIG. 5 along with FIG. 4, in the light conversion sheet 300 of the present invention, a prism in which light passing through the first light emitting sheet 320 is adjacent to the first and second light conversion layers 313 and 303. After being refracted in the patterns (area of the optical adhesive film 330), it can be seen that the light L proceeds toward the top of the second light emitting sheet 320.

In addition, the light that has been totally reflected in the upper region of the conventional light conversion sheet is recycled to the first light emitting sheet 320 by different refractive indices of the first and second light conversion layers 313 and 303, and then reflected and converted into light. It can be seen that light is emitted toward the top of the sheet 300.

As described above, the light conversion sheet of the present invention, a backlight unit and a liquid crystal display having the same, have an effect of improving light efficiency by arranging optical patterns inside the light conversion sheet.

In addition, the light conversion sheet of the present invention, a backlight unit having the same, and a liquid crystal display device, separate the light conversion sheet into a light conversion layer having a high refractive index and a light conversion layer having a low refractive index by optical patterns. There is an effect of improving the light efficiency.

6 and 7 are views showing the structure of a light conversion sheet according to another embodiment of the present invention, and FIG. 8 is a view showing light emission characteristics of the light conversion sheet having the structure of FIG. 7.

Since the material and diameter of the quantum dots of the light conversion sheet described herein, the material of the optical adhesive film, and the content of the bead are the same as those described in FIG. 4, the following description will be mainly made.

Referring to FIG. 6, a light conversion sheet 400 according to another embodiment of the present invention includes a first light emitting sheet 420 and a second light emitting sheet 410.

The first light emitting sheet 420 is composed of a first barrier layer 412 and a first light conversion layer 413 on a first substrate 411, and the second light emitting sheet 410 is a second substrate ( It is composed of a second barrier layer 402 and a second light conversion layer 403 on the 401. The first and second barrier layers 412 and 402 may be formed of an inorganic material.

The first and second light conversion layers 413 and 403 disposed on the first light emitting sheet 420 and the second light emitting sheet 410 are implemented in a pattern of a lens structure (Lenticular Type), and the first light emitting sheet The 420 and the second light emitting sheet 410 were attached to each other by an optical adhesive film 430 (Optical Clear Resin).

The light conversion sheet 400 has optical patterns disposed therein, the structure of the optical pattern is formed in a lens structure, and the cross section is formed in a streamlined structure of convex and concave shapes. Therefore, the cross-sectional structure of the optical adhesive film 430 disposed in the area where the first light conversion layer 413 and the second light conversion layer 403 are in contact is realized in the form of convex and concave streamlined structures in the form of continuous patterns. .

As described above, when optical patterns having a lens structure are formed inside the light conversion sheet 400, light traveling from the first light-emitting sheet 420 is transmitted from the streamlined optical patterns (optical adhesive film area) to various angles. Refraction and reflection are performed to improve light efficiency.

That is, in the light conversion sheet structure in which the light conversion layer is formed in the form of a single horizontal layer as in the prior art, the total reflection area of light is formed wide, resulting in large optical loss. It has the effect of reducing leakage light by forming it with specific optical patterns.

Further, although not shown in the drawings, a light diffusion layer including a plurality of light diffusing agents such as beads may be coated on the outer surface of the first light emitting sheet 420 and the outer surface of the second light emitting sheet 410. .

The first and second quantum dots Q1 and Q2 may be red quantum dots that generate red light and green quantum dots that generate green light, respectively.

In addition, the first and second photoconversion layers 413 and 403 may be formed by mixing any one of the first and second quantum dots Q1 and Q2 and a red or green phosphor corresponding thereto.

In addition, it is preferable that the resin refractive index of the second light conversion layer 403 is greater than the resin refractive index of the first light conversion layer 413. This is to improve light emission efficiency by preventing total reflection from occurring in the second light-emitting sheet 410 of light traveling from the first light-emitting sheet 420.

Referring to FIG. 7, a light conversion sheet 500 according to another embodiment of the present invention includes a first light emitting sheet 520 and a second light emitting sheet 510, and the first light emitting sheet 520 A first barrier layer 512 and a first light conversion layer 513 are formed on the first substrate 511, and the second light emitting sheet 510 is formed on the second substrate 501. 502) and a second light conversion layer 503.

The first and second light conversion layers 513 and 503 disposed on the first light emitting sheet 520 and the second light emitting sheet 510 are implemented in a rectangular type pattern, and the first light emitting sheet The 520 and the second light emitting sheet 510 were attached to each other by the optical adhesive film 530.

The light conversion sheet 500 has optical patterns disposed therein, and the optical pattern has a rectangular structure, and a cross section has a convex and concave rectangular structure.

As described above, when the optical patterns having a rectangular structure are formed inside the light conversion sheet 500, the light traveling from the first light emitting sheet 520 is in the optical adhesive film 530 area at various angles (areas in which optical patterns are formed) Refraction and reflection are made in the light source, thereby improving light efficiency.

That is, as in the prior art, in the light conversion sheet structure in the form of a single horizontal layer, the total reflection area of light is formed wide, but by forming the optical patterns as described above, there is an effect of minimizing the total reflection area to reduce leakage light.

In addition, it is preferable that the resin refractive index of the second photoconversion layer 503 is greater than the resin refractive index of the first photoconversion layer 513. This is to improve light emission efficiency by preventing total reflection from occurring in the second light emitting sheet 510 by light traveling from the first light emitting sheet 520.

Referring to FIG. 8 along with FIG. 7, in the light conversion sheet 500 on which optical patterns having a rectangular structure are formed, light passing through the first light emitting sheet 520 is transmitted to the first and second light conversion layers 513 and 503. After being refracted in the adjacent prism patterns (area of the optical adhesive film 530), it can be seen that the majority of light L proceeds toward the top of the second light emitting sheet 520.

In addition, light that has been totally reflected in the upper region of the conventional light conversion sheet is recycled to the first light emitting sheet 520 by different refractive indices of the first and second light conversion layers 513 and 503, and then reflected and converted into light. It can be seen that light is emitted toward the top of the sheet 500.

That is, it is possible to minimize a structure in which light is confined inside the light conversion sheet as in the prior art, and thus light emission efficiency can be improved.

As described above, the light conversion sheet of the present invention, a backlight unit and a liquid crystal display having the same, have an effect of improving light efficiency by forming optical patterns inside the light conversion sheet.

In addition, the light conversion sheet of the present invention, a backlight unit having the same, and a liquid crystal display device, separate the light conversion sheet into a light conversion layer having a high refractive index and a light conversion layer having a low refractive index by optical patterns. There is an effect of improving the light efficiency.

100: liquid crystal display device 110: liquid crystal display panel
112: first substrate 114: second substrate
117: printed circuit board 120: backlight unit
210: optical sheet 123: light guide plate
125: reflector 130: support main
300: light conversion sheet 310: first light emitting sheet
320: second light emitting sheet

Claims (17)

A first light emitting sheet including a first substrate and a first light conversion layer disposed on the first substrate;
A second light emitting sheet including a second substrate and a second light conversion layer disposed on the second substrate;
First and second quantum dots and beads included in the first and second photoconversion layers; And
Including an optical adhesive film disposed between the first and second light conversion layers so that the first and second light emitting sheets are bonded,
The first light conversion layer includes a convex and concave pattern formed to face the second light emitting sheet,
The second light conversion layer includes convex and concave patterns formed to face the first light emitting sheet,
The convex pattern of the first light conversion layer and the concave pattern of the second light conversion layer are formed to mesh with each other, and the concave pattern of the first light conversion layer and the second light conversion The photoconversion sheet formed so that the convex pattern of the layer meshes with each other.
The light conversion sheet of claim 1, wherein the pattern of each of the first and second light conversion layers has a prism structure, a lens structure, a cone structure, a pyramid structure, or a rectangular structure.
The photoconversion sheet of claim 1, wherein the first and second quantum dots have a diameter of 0.5 nm to 30 nm.
The method of claim 1, wherein the resin used in the first and second light conversion layers is poly(methyl(meth)acrylate), poly(ethylene glycol dimethacrylic). Rate) (poly(ethylene glycol dimethacrylate), polyvinyl acetate, poly(divinyl benzene)), poly(thioether)), silica, polyepoxide And a light conversion sheet, characterized in that made of a combination of these.
The light conversion sheet according to claim 1, wherein the optical adhesive film further comprises beads.
Light source;
A light guide plate that converts the light source into surface light;
A light conversion sheet disposed on the light guide plate;
An optical sheet disposed on the light conversion sheet; And
Including a reflector disposed under the light guide plate,
The light conversion sheet includes a first light-emitting sheet including a first substrate, a first light conversion layer disposed on the first substrate, and a second light conversion layer disposed on the second substrate and the second substrate. The first and second light conversion layers so that the second light emitting sheet including, the first and second quantum dots and beads included in the first and second light conversion layers, and the first and second light emitting sheets are bonded together Including an optical adhesive film disposed between,
The first light conversion layer includes convex and concave patterns formed to face the second light-emitting sheet, and the second light conversion layer includes convex and concave patterns formed to face the first light-emitting sheet. And
The convex pattern of the first light conversion layer and the concave pattern of the second light conversion layer are formed to mesh with each other, and the concave pattern of the first light conversion layer and the second light conversion The convex pattern of the layer is formed to mesh with each other.
The backlight unit of claim 6, wherein the light source is composed of a blue LED.
The backlight unit of claim 6, wherein the pattern of each of the first and second light conversion layers has a prism structure, a lens structure, a cone structure, a pyramid structure, or a rectangular structure.
The backlight unit of claim 6, wherein the first and second quantum dots have a diameter of 0.5 nm to 30 nm.
The method of claim 6, wherein the resin used in the first and second light conversion layers is poly(methyl(meth)acrylate), poly(ethylene glycol dimethacrylic). Rate) (poly(ethylene glycol dimethacrylate), polyvinyl acetate, poly(divinyl benzene)), poly(thioether)), silica, polyepoxide And a backlight unit, characterized in that made of a combination of these.
The backlight unit of claim 6, wherein the optical adhesive film further comprises a bead.
A liquid crystal display panel; And
A light source to supply surface light to the liquid crystal display panel; a light guide plate for converting light incident from the light source into a surface light source; a light conversion sheet disposed on the light guide plate; an optical sheet disposed on the light conversion sheet; Including a backlight unit having a reflector disposed under the light guide plate,
The light conversion sheet includes a first light-emitting sheet including a first substrate, a first light conversion layer disposed on the first substrate, and a second light conversion layer disposed on the second substrate and the second substrate. The first and second light conversion layers so that the second light emitting sheet including, the first and second quantum dots and beads included in the first and second light conversion layers, and the first and second light emitting sheets are bonded together Including an optical adhesive film disposed between,
The first light conversion layer includes convex and concave patterns formed to face the second light-emitting sheet, and the second light conversion layer includes convex and concave patterns formed to face the first light-emitting sheet. And
The convex pattern of the first light conversion layer and the concave pattern of the second light conversion layer are formed to mesh with each other, and the concave pattern of the first light conversion layer and the second light conversion The liquid crystal display device formed so that the convex pattern of the layer meshes with each other.
The liquid crystal display device of claim 12, wherein the light source comprises a blue LED.
The liquid crystal display of claim 12, wherein the pattern of each of the first and second light conversion layers has a prism structure, a lens structure, a cone structure, a pyramid structure, or a rectangular structure.
The liquid crystal display of claim 12, wherein the first and second quantum dots have a diameter of 0.5 nm to 30 nm.
The method of claim 12, wherein the resin used in the first and second light conversion layers is poly(methyl(meth)acrylate), poly(ethylene glycol dimethacrylic). Rate) (poly(ethylene glycol dimethacrylate), polyvinyl acetate, poly(divinyl benzene)), poly(thioether)), silica, polyepoxide And a liquid crystal display device comprising a combination thereof.
The liquid crystal display of claim 12, wherein the optical adhesive film further comprises beads.

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