KR20170010422A - Reverse prism composite sheet and backlight unit and liquid crystal display device including the same - Google Patents

Abstract

The present invention relates to a reverse prism composite sheet, a backlight unit and a liquid crystal display device including the same for solving a Newtons ring phenomenon. According to an embodiment of the present invention, the reverse prism composite sheet includes: a reflective polarizing layer; and a plurality of prism parts arranged under the reflection polarizing layer and having a protruding prism. The present invention includes a particle dispersion layer having a plurality of scattering particles dispersed in a polymer layer. The reflective polarizing layer and the particle dispersion layer can be bonded to each other.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, a backlight unit,

The present invention relates to an optical sheet, and more particularly, to an inverse prism composite sheet, a backlight unit including the same, and a liquid crystal display.

2. Description of the Related Art In general, a liquid crystal display device (LCD) is a device for displaying a desired image by controlling a transmission amount of a light beam using a liquid crystal according to a signal applied to a plurality of control switches arranged in a matrix form .

Since such a liquid crystal display device is not a self-luminous display device, a separate light supply means such as a backlight unit is necessarily required.

The backlight unit is divided into direct-type or edge-type according to the position of the light source. In the direct type system, a plurality of light sources are arranged below the liquid crystal display panel, and light incident from the light sources is irradiated to the liquid crystal display panel through the diffusion plate and the plurality of optical sheets. In the edge type method, a light source is provided at one edge of a liquid crystal display device, and light incident from the light source is irradiated to the liquid crystal display panel through a light guide plate and a plurality of optical sheets.

For example, a conventional edge type backlight unit is disposed below a liquid crystal display panel and includes a light source disposed at least at one side, a light guide plate uniformly distributing light incident from the light source over the entire area of the liquid crystal display panel, And optical sheets disposed between the light guide plate and the liquid crystal display panel to scatter and condense the light incident from the light guide plate and enter the lower portion of the liquid crystal display panel.

In general, an optical sheet is composed of a prism sheet and a reflective polarizing layer.

The conventional prism sheet includes a triangular prism pattern, and the prism pattern is formed to protrude toward the liquid crystal display panel. The conventional backlight unit includes two such prism sheets, and the two prism sheets are stacked so that the extending directions of the prism patterns intersect vertically. In recent years, however, a prism pattern layer has been used which can reduce the total thickness of the backlight unit by replacing a plurality of prism sheets, while improving the light collection efficiency of light incident from the light guide plate.

The prism pattern layer is a sheet in which a triangular prism pattern protrudes toward the light guide plate. A prism pattern layer is disposed on the light guide plate, and a reflective polarizer layer is disposed on the prism pattern layer.

Even when one prism pattern layer is disposed, it is possible to obtain a light-condensing efficiency higher than that in the case where a plurality of prism sheets are conventionally disposed, which is very efficient. However, since the opposing surfaces of the prism pattern layer and the reflective polarizing layer are flat plate-like, there is a problem that Newton's Ring phenomenon frequently occurs as a part of the sheet is separated and contacted during lamination.

The Newton ring phenomenon refers to a phenomenon in which an annular pattern of light interference fringes is generated around a contact area when a gap between sheets is linearly changed in a state where some contact areas exist between stacked sheets.

Such a Newton ring phenomenon is projected onto the liquid crystal display panel as it is and seriously affects the image quality of the image displayed through the liquid crystal display panel.

Therefore, there is a need to solve the Newton ring phenomenon while improving the light condensing efficiency by using the prism pattern layer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inverse prism composite sheet capable of solving the Newton ring phenomenon, a backlight unit including the same, and a liquid crystal display device.

The reverse prism hybrid sheet according to an embodiment of the present invention includes a reflective polarizer layer; And a particle dispersion layer disposed on the lower portion of the reflective polarizing layer and including a plurality of prism portions having projected prism mountains and including a plurality of scattering particles dispersed in the polymer layer, The dispersion layers can be stuck together.

The protrusion height of the prism mountain may be 10 to 60 탆.

At least two or more prism portions of the prism portions may have different projecting heights of the prism mountains.

The angle formed between the vertical line drawn on the flank of the prism mountain and the side faces constituting the prism mountain may be equal to each other.

The angle formed between the vertical line drawn on the flank of the prism mountain and the side faces forming the prism mountain may be different from each other.

The inner angle of the prism mountains may be 50 to 70 degrees.

The distance between the vertexes of the prism mountains may be 10 to 80 탆.

At least one side surface of the prism mountains may be bent at least once.

The prism mountain may have a curved cross-sectional shape.

The plurality of scattering particles may be formed of the same material.

The plurality of scattering particles may include at least two kinds of materials.

The plurality of scattering particles may include at least one of ZrO ₂ , TiO ₂ , Al ₂ O ₃ , MgO, and SiO ₂ .

The refractive index of the scattering particles may be 1.5 to 3.0, and the diameter may be 0.1 to 3.0 탆.

The scattering particle content in the particle dispersion layer may be 0.5 to 50 wt% based on the weight of the particle dispersion layer.

The refractive index difference between the scattering particles and the polymer layer may be 0.1 to 1.6.

The thickness of the particle dispersion layer may be 1 to 100 mu m.

The reflective polarizing layer may be formed by alternately stacking at least two or more sublayers formed of different polymer materials.

A backlight unit according to an embodiment of the present invention includes at least one light source for generating light; A reflective polarizing layer, and a particle dispersed layer disposed on a lower portion of the reflective polarizing layer and including a plurality of prism portions having prism mountains protruding downward, wherein the reflective polarizing layer and the particle dispersing layer are composed of a reverse prism Composite sheet; And a light guide layer disposed below the reverse prism composite sheet and transmitting light from the light source to the reverse prism composite sheet.

A liquid crystal display according to an embodiment of the present invention includes a liquid crystal display panel; An inverted prism composite sheet disposed under the liquid crystal display panel; At least one light source for generating light; And a light guide layer disposed below the reverse prism composite sheet and transmitting light from the light source to the reverse prism composite sheet, wherein the reverse prism composite sheet comprises a reflective polarizer layer, And a plurality of prism portions having prism mountains protruded downward, wherein the reflective polarizer layer and the particle dispersion layer can be attached to each other.

According to the present invention, since the reflective polarizing layer and the prism pattern layer are integrally formed, there is no space between the prism pattern layer and the reflective polarizing layer, so the Newton ring phenomenon can be solved.

In addition, according to the present invention, the viewing angle can be enlarged by integrally forming the particle dispersion layer on the reflective polarizing layer.

1 is a view schematically showing a configuration of a liquid crystal display device including a reverse prism composite sheet according to an embodiment of the present invention.
2 is a view showing an embodiment of a prism pattern layer.
Figs. 3A to 3C are views showing an embodiment of prism angle. Fig.
4 is a diagram showing the relationship between the prism angle, the center luminance, and the upper and lower viewing angles.
5A and 5B are views showing other embodiments of a prism pattern layer.
6 is a view showing an embodiment of the particle dispersion layer.
7 is a view showing an embodiment of a reflective polarizing layer.
8 and 9 are views showing other embodiments of the reverse prism composite sheet according to the present invention.
10 and 11 are views showing another embodiment of a backlight unit and a liquid crystal display device to which the reverse prism composite sheet according to the present invention is applied.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

Likewise, when an element such as a layer, film, region, plate, or section is referred to as being "on" another element, such element is not only "directly above" another element, . Conversely, when an element is referred to as being "directly on" another element, it means that there are no other elements in between.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a view schematically showing a configuration of a liquid crystal display device including a reverse prism composite sheet according to an embodiment of the present invention.

Referring to FIG. 1, the reverse prism composite sheet 20 according to an embodiment of the present invention may be disposed below the liquid crystal display panel 10.

The reverse prism composite sheet 20 may include a particle dispersion layer 21, a reflective polarizing layer 22, and a prism pattern layer 23. [

The prism pattern layer 23 is disposed on the lower portion of the reflective polarizing layer 22. The prism pattern layer 23 is disposed on the reflective polarizing layer 22. The prism pattern layer 23 is disposed below the reflective polarizing layer 22, And a plurality of prism portions having an acid.

In one embodiment of the present invention, the particle dispersion layer 21, the reflective polarizing layer 22, and the prism pattern layer 23 may be integrally formed.

In the present invention, the integral type means that each layer is formed by one sheet so that the layers are bonded together so that there is no space between the layers. That is, in the present invention, the integral type may be formed by bonding each layer using a separate adhesive layer, or by forming each layer so as to have adhesiveness and bonding each other, or coating one layer on another surface, Forming the layer directly on the other layer.

In one embodiment, the prism pattern layer 23 may be formed directly on the lower surface of the reflective polarizing layer 22. In another embodiment, when the prism pattern layer 23 is provided with a prism pattern formed on the base layer, the prism pattern is formed on the lower surface of the base layer, and the upper surface of the base layer is bonded to the reflective polarizer layer 22 . In another embodiment, the particle dispersed layer 21 is formed of a material having adhesiveness, and can be bonded to the reflective polarizing layer 22 without a separate adhesive layer.

Accordingly, in the prior art, the Newton ring phenomenon occurs because the prism pattern layer 23 and the reflective polarizer layer 22 are separated from each other. However, in the present invention, since each layer is formed integrally, the prism pattern layer 23, There is no spacing space between the layers 22, so that the Newton ring phenomenon is cut off from the source.

In addition, conventionally, there is a problem that the luminance is improved by stacking the prism pattern layer 23 and the reflective polarizing layer 22, but the viewing angle is lowered. However, in the present invention, since the particle dispersion layer 21 for diffusing light is further formed on the reflective polarizing layer 22, even if the viewing angle decreases due to the lamination of the prismatic layer 23 and the reflective polarizing layer 22 , And can compensate for this.

In addition, since the particle dispersion layer 21, the reflective polarizing layer 22, and the prism pattern layer 23 are integrally formed, the present invention has a simple effect of assembling the liquid crystal display device during manufacture, It is possible to prevent the occurrence of warpage compared to a case where the sheets are simply laminated.

The particle dispersion layer 21, the reflective polarizing layer 22, and the prism pattern layer 23 constituting the reverse prism composite sheet 20 will be described in detail later.

The light source 30 and the light guide layer 40 may be disposed under the reverse prism composite sheet 20. [ 1 shows an edge type backlight unit in which a light source 30 is formed on one side of a light guide layer 40 and a light guide layer 40 is formed on a light guide plate. However, this is only an embodiment, and the reverse prism composite sheet 20 of the present invention can be applied to both the edge type or direct type. That is, in the direct-type backlight unit, the light guide layer 40 under the reverse-prism composite sheet 20 may be provided as a diffusion plate, and a plurality of the light sources 30 are disposed under the light guide layer 40 .

In the embodiment of FIG. 1, the light source 30 can supply predetermined light corresponding to the current supplied from an external power source toward the light guide layer 40. The light guide layer 40 can uniformly distribute the light incident from the light source 30 over the entire area of the light guide layer 40. [ That is, the light guide layer 40 allows the light incident from the light source 30 to be uniformly incident on the reversed prism composite sheet 20, so that the light shadow region is not generated.

A reflective plate 50 may be disposed below the light guide layer 40. The reflection plate 50 may reflect light incident on the lower portion of the light guide layer 40. That is, the reflection plate 50 can prevent the light from being wasted by reflecting the light incident from the light guide layer 40 in the direction of the light guide layer 40 to be supplied to the liquid crystal display panel 10 .

The back prism composite sheet 20, the light source 30, the light guide layer 40, and the reflector 50 are collectively referred to as a backlight unit except for the liquid crystal display panel 10 in the embodiment of FIG. .

Hereinafter, the reverse prism composite sheet 20 will be described in more detail with reference to Figs. 2 to 7. Fig.

2 is a view showing an embodiment of the prism pattern layer 23 provided at the bottom of the reverse prism composite sheet 20. As shown in FIG.

The prism pattern layer 23 of FIG. 2 may be composed of a base layer 23a and a prism portion 23b. A manufacturing process of the prism pattern layer 23 will be briefly described. First, a base layer 23a and a prism pattern mold are provided. The prism pattern mold may have a shape corresponding to a prism pattern to be formed, as a mold for forming a prism pattern structure, that is, a prism portion 23b, in the base layer 23a. Next, the prepared base layer 23a is combined with the prism pattern mold to fill the space between the base layer 23a and the prism pattern mold with a resin. After the process such as squeezing and curing, the base layer 23a and the prism pattern mold are released. Thus, the cured resin is bonded to the base layer 23a, so that the prism portion 23b can be formed.

The resin used for forming the prism pattern layer 23 preferably has a refractive index of 1 to 1.55. If the refractive index of the resin is out of the range of 1 to 1.55, there is a problem that the center emergence efficiency is lowered.

2, the prism pattern layer 23 formed through the same process as in the above embodiment may include a plurality of prism portions 23b and a base layer 23a for supporting and fixing the prism portions 23b.

On the other hand, in another embodiment, the prism pattern layer 23 can be directly formed on the lower surface of the reflective polarizing layer 22 using a prism pattern mold and resin without using a separate base layer 23a. That is, in this case, the reflective polarizing layer 22 serves as a support member for forming the prism pattern layer 23. According to this embodiment, when forming the prism pattern layer 23, a resin residual layer may be formed on the contact surface with the reflective polarizing layer 22. The resin residual layer may be intentionally formed to firmly fix the prism pattern, or may be formed due to a gap between the prism pattern mold and the reflective polarizer layer 22 or the like. At this time, the region of the resin residual layer may be defined as a region excluding the protruded prism acid. The thus formed resin residual layer may consequently be the base layer 23a of Fig. In other words, even when the prism pattern layer 23 is directly formed on the lower surface of the reflective polarizing layer 22, the prism pattern layer 23 is formed by the base layer 23a formed by residual resin And a prism portion 23b, which is a prism pattern.

In another embodiment, the prism pattern layer 23 may be formed as a single layer through mold forming. The prism portion 23b is formed by using the base layer 23a and the prism pattern mold in the embodiment described above and the prism pattern is formed by using the prism pattern mold with the reflective polarizing layer 22 as a supporting member in another embodiment, Layer 23 is formed. However, in another embodiment, an independent prism pattern layer 23 can be formed by providing a mold structure for forming the prism pattern layer 23, injecting resin into the mold structure, and curing. The prism pattern layer 23 thus formed may be attached to the reflective polarizing layer 22 by using an adhesive layer or an adhesive material. In this case also, a resin residual layer may be formed on the prism pattern layer 23 as in the above-described other embodiments, whereby the prism pattern layer 23 is formed by the base layer 23a due to resin residual, And an in-prism portion 23b.

In the above embodiments, the thickness A of the base layer 23a may be 0 to 300 mu m. That is, when the prism pattern is directly formed on the reflective polarizing layer 22 or when the entire prism pattern layer 23 is molded, the base layer 23a may not exist (thickness is 0). On the other hand, in the case where a separate base layer 23a is provided as a supporting member (one embodiment) or a resin residual layer is formed (another embodiment, another embodiment), the thickness of the base layer 23a may occur . At this time, it is preferable that the thickness A of the base layer 23a is formed to a maximum of 300 mu m in order to prevent the light transmission characteristic from being lowered while supporting and fixing the prism portion 23b.

The base layer 23a may be formed of a polymer, an oligomer, a monomer, or a combination of two or more thereof. For example, materials such as polyesters, polyester copolymers (PET, PEN, CoPEN, CoPET), polycarbonate (PC), polyethersulfone (PES), acrylic (PMMA), cycloolefin The base layer 23a can be formed.

On the other hand, the prism mount projecting height B of the prism portion 23b may be 10 to 60 탆. 2, the prism pattern protruding height B referred to in the present invention is not limited to the case where the prism pattern layer 23 is composed of the base layer 23a and the prism portion 23b, And the prism portion 23b having a prism mountain without the base layer 23a.

The prism mountain projected height B can be defined as the projected height of the prism mountain itself. More specifically, the prism mountain protrusion height B may refer to the length of the waterline falling on the surface where the prism portion 23b and the base layer 23a contact with each other at the vertex of the prism mountain of the prism portion 23b. In the absence of the base layer 23a, the prism mountain projecting height B is set such that the prism mountain projected height B is different from the projected height B of the prism portion 23b with respect to the other constitution (for example, the reflective polarizing layer 22) It may be the length of the waterline on the contact surface.

Here, the prism mount projecting heights B of the respective prism portions 23b do not have to be the same. That is, at least one of the plurality of prism portions 23b may have a prism mountain protrusion height B different from the prism mountain protrusion height B of the other prism portion 23b, It can be designed according to the function of the backlight unit required by the apparatus.

In addition, angles (C, D) formed by the sides of the prism portions of the respective prism portions (23b), specifically, the angles (C, D) formed by the vertical lines drawn on the flank and the sides of the prism mountain, .

3A is an illustration showing an example in which two angles C and D are the same and an embodiment in Fig. 3B is an example in which an angle D on the right side is larger than an angle C on the left side, 3C is an illustration showing an example in which the angle C of the left side is larger than the angle D of the right side.

This angle configuration has a different light converging effect depending on the position of the light source 30.

Referring to FIG. 4, when the angles C and D of both sides are the same, the center luminance is 100%, while the upper and lower viewing angles are 20 degrees and the luminance is high, while the upper and lower viewing angles are very narrow. The upper and lower viewing angles refer to the degree of the light spreading in the vertical direction of the liquid crystal display panel 10 when the liquid crystal display panel 10 is viewed. However, when the angle of the right side surface D is larger than the angle of the left side surface C, the center luminance is 68% and the upper and lower viewing angles are 28 degrees, , But there is a difference that the upper and lower viewing angles are widened.

Therefore, by controlling the prism angle of the prism portion 23b, the luminance and the vertical viewing angle can be adjusted according to the use of the liquid crystal display device.

On the other hand, the sum of both side angles C and D, that is, the total internal angle C + D of the prism mountains is preferably 50 to 70 degrees, but is not limited thereto.

In FIG. 2, the distance between the prism mountains, specifically, the distance E between the vertexes of the prism mountains may be 10 to 80 μm. When the distance (E) between the prisms is 10 to 80 mu m, there is an advantage that the light efficiency characteristics are improved.

Here, all the prism mountain intervals E need not be the same. It is also possible to intentionally and randomly form the prism mountain interval E in order to prevent the phenomenon of moire or the like.

Figs. 5A and 5B are views showing other embodiments of the prism pattern layer 23. Fig.

5A and 5B, the prism acid includes an incident surface on which light is incident and an exit surface on which incident light is emitted upward.

In the embodiment of the present invention, at least one of the incident surface and the emergent surface of the prism mountain is bent at least once to control the luminance and the viewing angle.

In the embodiments of Figs. 5A and 5B, the outgoing plane of the two planes is bent at least once. Fig. 5A shows that the exit surface is bent once to the outside, and Fig. 5B is a view showing that the exit surface is bent once inside.

In addition, although not shown in the drawing, a prism mountain of the prism portion 23b may be formed as a curved surface. In particular, the prism mountain may have a curved cross section. Similarly, when the incident surface or the exit surface is bent, the bent surface may have a predetermined angle as shown in Figs. 5A and 5B, or may have a curved shape. In addition, the shape of the prism mountains can be modified into various shapes as needed.

6 is a view showing an embodiment of the particle dispersion layer 21 of the reverse prism composite sheet 20. As shown in Fig.

Referring to Fig. 6, the particle dispersion layer 21 may include a polymer layer 21a and scattering particles 21b.

The polymer layer 21a may be formed of the same material as the polymer resin to fix the scattering particles 21b and the scattering particles 21b may be dispersed in the polymer layer 21a.

The scattering particles 21b may be composed of a scattering body formed of a single kind of material, or may be composed of scattering bodies formed of at least two kinds of different materials. For example, the scattering particles (21b) may include at least one of _{ZrO 2, TiO 2, Al 2} O 3, MgO, and SiO _2. As the scattering particles 21b, particles having a refractive index of 1.5 to 3.0 may be used, and a difference in refractive index from a material forming the polymer layer 21a is preferably 0.1 to 1.6. When the refractive index difference is 0.1 or less, the effect of dispersing the scattering particles 21b in the polymer layer 21a is insignificant. When the refractive index difference is 1.6 or more, the mass dispersibility of the particle dispersion layer 21 may be deteriorated.

On the other hand, the diameter of the scattering particles 21b may be 0.1 to 3.0 mu m. As the diameter of the scattering particles 21b increases, back scattering, which is scattered again in the direction in which the light is incident, decreases and the luminance increases. When the scattering particles 21b are larger than 3.0 m, the visibility of the particles increases, have. If the diameter of the scattering particles 21b is less than 0.1 占 퐉, the back scattering increases and the luminance may be lowered. In the case where particles having a diameter similar to that of the visible light region are used as the scattering particles 21b, the Mie scattering effect is maximized and the forward scattering can be enhanced, and the appearance improvement through the adjustment of the haze It is easy. Here, the diameter of the scattering particles 21b is a straight line distance between two points on the particle surface, and is a length of a virtual straight line connecting two points while passing through the center of gravity of the particle. However, when the linear distance varies depending on the positions of two points, such as the shape of an egg or the like, the diameter of the particle means the maximum of the linear distances.

The content of the scattering particles 21b in the particle dispersion layer 21 may be 0.5 to 50 wt% based on the weight of the particle dispersion layer 21. In this case, the particle dispersion layer 21 may have a haze of about 20 to 90% Lt; / RTI >

Table 1 shows the relationship between the content, haze, vertical viewing angle and luminance when the thickness of the particle dispersion layer 21 is 25 占 퐉 and Al ₂ O ₃ is used as the scattering particles 21b. Here, the content and haze are the results of measuring the particle dispersion layer 21, and the upper and lower viewing angles and luminance are the results of measuring the reverse prism composite sheet 20 of FIG.

S1

S2

S3

S4

S5

content
(Al2O3)

-
0.5 wt%
1.5wt%
3wt%
6wt%
Hayes

-
25%
45%
65%
80%
Upper and lower viewing angles

19 °
23.5 DEG
25 °
28.5
34 °
Luminance

100%
83.3%
78.4%
66.5%
52.7%

Referring to Table 1, as the content of the scattering particles 21b increases, the upper and lower viewing angle widths increase nonlinearly and the luminance decreases as the haze increases.

That is, the upper and lower viewing angles and the luminance can be controlled by controlling the content of the scattering particles 21b.

The polymer layer 21a may be formed by curing a thermosetting composition or a photo-curable composition.

The thermosetting composition used as the polymer layer 21a may comprise a thermosetting resin and a thermosetting agent. At this time, the thermosetting resin may be at least one of an acrylic resin, a silicone resin and an epoxy resin. As the thermosetting agent, an isocyanate compound, an amine compound, an organic acid anhydride compound, an amide compound, a dialdehyde compound, A metal chelate compound, a metal alkoxide compound, and a metal salt may be used. However, the present invention is not limited thereto, and both thermosetting resins and thermosetting agents which are generally used can be applied.

The photo-curable composition used as the polymer layer 21a may be composed of a photo-curing resin and a photo-initiator. At this time, the photopolymerizable resin may be a single polymer, oligomer or monomer, or a combination of two or more thereof. As the polymer and oligomer, an acrylic resin, a silicone resin, an epoxy resin and the like may be used, but not limited thereto, various combinations can be utilized.

On the other hand, the total thickness of the particle dispersion layer 21 may be 1 to 100 mu m. If the thickness is less than 1 탆, back scattering can be large. When the thickness exceeds 100 mu m, the light absorption efficiency of the particle dispersed layer 21 is increased, and the light efficiency may be lowered.

7 is a view showing one embodiment of the reflective polarizing layer 22.

The reflective polarizing layer 22 may be formed as a single layer as an optical sheet that transmits only light that vibrates in a specific direction among the incident light while vibrating in various directions and reflects light that vibrates in the other direction, A plurality of sublayers may be stacked.

Referring to FIG. 7, the reflective polarizer layer 22 may be formed by alternately stacking a first sub-layer 22a and a second sub-layer 22b.

The first and second sublayers 22a, 22b may each be formed through a polymeric material, which may be formed of different polymeric materials. For example, in the case where the second sub-layer 22b is formed of a material whose refractive index hardly changes even after the stretching process, the first sub-layer 22a is formed of a material whose refractive index changes with respect to the stretching direction can do. Due to this characteristic, the reflective polarizing layer 22 transmits light that vibrates in a desired direction, and does not transmit light that vibrates in other directions.

In the embodiment of Fig. 7, the sublayers 22a and 22b constituting the reflective polarizing layer 22 can set the number of layers as required, and two sublayers 22a and 22b are alternately stacked However, the present invention is not limited thereto, and the reflective polarizing layer 22 may be formed by alternately laminating three or more sublayers.

The particle dispersion layer 21 may be formed on the upper surface of the reflective polarizer layer 22 so that the particle dispersion layer 21 is adhered to the upper surface of the reflective polarizer layer 22 during the curing process. A prism pattern layer 23 is bonded to the lower surface of the reflective polarizing layer 22. The prism pattern layer 23 may also be adhered to the lower surface of the reflective polarizing layer 22 during the curing process. On the other hand, when the prism pattern layer 23 includes the base layer 23a and the prism portion 23b formed by curing on one surface of the base layer 23a, And the other surface may be bonded to the reflective polarizing layer 22.

8 is a view showing another embodiment of the reverse prism composite sheet 20 according to the present invention.

1, a prism pattern layer 23 is formed below the reflective polarizing layer 22 when viewed from the reflective polarizing layer 22 and a dispersed layer 21 is formed on the reflective polarizing layer 22 Is formed.

8, the prism pattern layer 23 is formed on the bottom of the particle dispersion layer 21 and the reflective polarizer layer 21 is formed on the top of the particle dispersion layer 21, 22 are formed.

At this time, the particle dispersion layer 21 is composed of a polymer layer in which scattering particles are dispersed as described above, and can be adhered to the reflective polarizing layer 22 in the process of curing the polymer layer.

Accordingly, since the particle dispersion layer 21 acts as an adhesive layer between the reflective polarizing layer 22 and the prism pattern layer 23, the reflective polarizing layer 22 and the prism pattern layer 23 can be bonded without a separate adhesive layer It is possible to easily form the reverse prism composite sheet 20 in which the reflective polarizing layer 22, the particle dispersion layer 21, and the prism pattern layer 23 are integrated.

9 is a view showing still another embodiment of the reverse prism composite sheet 20 according to the present invention.

In the embodiment shown in Figs. 1 and 8, the reflective polarizing layer 22, the dispersed particle layer 21 and the prismatic layer 23 are separately formed and attached to each other. In the embodiment shown in Fig. 9, A plurality of prism portions 21a having prism mountains projected toward the light guide layer 40 are formed on the prism portion 21 itself.

That is, when the curable composition in which scattering particles are dispersed is cured to form the particle dispersion layer 21, a prism pattern can be formed on one surface. Since the method of forming the prism pattern is the same as that described above, a detailed description thereof will be omitted.

Accordingly, the configuration of the reverse prism composite sheet 20 is further simplified, and the process of forming and attaching the particle dispersion layer 21 and the prism pattern layer is omitted, thereby shortening the manufacturing process and reducing the manufacturing cost It is effective.

10 and 11 are views showing another embodiment of a backlight unit and a liquid crystal display device to which the reverse prism composite sheet 20 according to the present invention is applied.

10 shows an example in which the reverse prism composite sheet 20 and the liquid crystal display panel 10 are integrally formed.

In this structure, since the particle dispersed layer 21 acts as an adhesive, it is possible to simplify the assembling of the liquid crystal display device and to improve the rigidity of the liquid crystal display panel 10 and the reverse prism composite sheet 20 .

11 shows an example in which a protective sheet 60 is added between the reverse prism composite sheet 20 and the light guide layer 40. [

That is, the backlight unit of Fig. 11 may further include the protection sheet 60. [

When the reverse prism composite sheet 20 and the light guide layer 40 are in contact with each other due to an external pressure or the like, scratches or the like may be formed on the surface of the light guide layer 40, There is a possibility of occurrence.

Such a scratch may affect the light pattern emitted through the light guide layer 40, thereby causing light to be emitted in an unintended direction.

Therefore, by arranging the protective sheet 60 between the reverse prism composite sheet 20 and the light guide layer 40, scratch of the light guide layer 40 can be prevented. At this time, the protective sheet 60 is preferably formed of a light transmitting material so as not to block the light from the light source 30.

10 and 11 show the reverse prism composite sheet 20 shown in Fig. 1, the reverse prism composite sheet 20 used in the embodiments of Figs. 10 and 11 is not limited to this, It is needless to say that the reverse prism composite sheet 20 of the above-mentioned embodiment including the embodiment of FIGS.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

10: liquid crystal display panel 20: reverse prism composite sheet
21: Particle dispersion layer 21a: Polymer layer
21b: scattering particles 22: reflective polarizing layer
22a, 22b: sublayer 23: prism pattern layer
23a: base layer 23b: prism portion
30: light source 40: light guide layer
50: reflector 60: protective sheet

Claims (19)

A reflective polarizing layer; And
And a plurality of prism portions disposed at a lower portion of the reflective polarizing layer and having protruded prism mountains, wherein the particle dispersion layer includes a plurality of scattering particles dispersed in the polymer layer,
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Wherein the reflective polarizing layer and the particle dispersion layer are bonded together.
The method according to claim 1,
And the projection height of the prism mountain is 10 to 60 占 퐉.
The method according to claim 1,
Wherein at least two or more prism portions of the prism portions have different projecting heights of prism mountains.
The method according to claim 1,
Wherein an angle formed between a vertical line drawn on the flank of the prism mountain and a side surface of the prism mountain are equal to each other.
The method according to claim 1,
Wherein an angle formed by a vertical line drawn on the flank of the prism mountain and a side surface of the prism mountain are different from each other.
The method according to claim 1,
And an inner angle of the prism mountains is 50 to 70 degrees.
The method according to claim 1,
Wherein an interval between vertexes of the prism mountains is 10 to 80 占 퐉.
The method according to claim 1,
And at least one side surface of each of the side surfaces constituting the prism mountain is bent at least once.
The method according to claim 1,
Wherein the prism mountain has a curved cross-sectional shape.
The method according to claim 1,
Wherein the plurality of scattering particles are made of the same material.
The method according to claim 1,
Wherein the plurality of scattering particles comprise at least two kinds of materials.
The method according to claim 1,
Prism composite sheet of the plurality of scattering particles include at least one of _{ZrO 2, TiO 2, Al 2} O 3, MgO, and SiO _2.
The method according to claim 1,
Wherein the scattering particles have a refractive index of 1.5 to 3.0 and a diameter of 0.1 to 3.0 占 퐉.
The method according to claim 1,
Wherein the scattering particle content in the particle dispersion layer is 0.5 to 50 wt% based on the weight of the particle dispersion layer.
The method according to claim 1,
And the refractive index difference between the scattering particles and the polymer layer is 0.1 to 1.6.
The method according to claim 1,
Wherein the thickness of the particle dispersion layer is 1 to 100 占 퐉.
The method according to claim 1,
Wherein the reflective polarizer layer is formed by alternately laminating at least two or more sublayers formed of different polymer materials.
At least one light source for generating light;
A reflective polarizing layer, and a particle dispersed layer disposed on a lower portion of the reflective polarizing layer and including a plurality of prism portions having prism mountains protruding downward, wherein the reflective polarizing layer and the particle dispersing layer are composed of a reverse prism Composite sheet; And
A light guiding layer disposed below the reverse prism composite sheet for transmitting light from the light source to the reverse prism composite sheet,
.
A liquid crystal display panel;
An inverted prism composite sheet disposed under the liquid crystal display panel;
At least one light source for generating light; And
A light guiding layer disposed below the reverse prism composite sheet for transmitting light from the light source to the reverse prism composite sheet,
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Wherein the inverse prism composite sheet is composed of a reflective polarizing layer and a particle dispersed layer including a plurality of prism portions disposed below the reflective polarizing layer and having a prism acid protruding downward, Are attached to each other.

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