KR101871548B1 - Light guide film, back light unit comprising the same, and liquid crystal display apparatus comprising thereof - Google Patents

Abstract

The present invention relates to a substrate layer; An optical pattern layer formed on the base layer, and an adhesion promoting layer formed between the base layer and the optical pattern layer, wherein DELTA Haze value represented by the following formula (1) is 0.3 or less.
<Formula 1>
ΔHaze = Hp-Hs
In the above equation, Hs is the haze value only for the base layer, and Hp is the haze value for the state in which the adhesion increasing layer is formed on the base layer.

Description

[0001] The present invention relates to a light guide film, a backlight unit including the light guide film, and a liquid crystal display device including the light guide film,

The present invention relates to a light guide film, a backlight unit including the same, and a liquid crystal display including the same.

The liquid crystal display device includes a backlight unit including a light source, a light guide plate, a reflection plate, a condensing sheet, and the like. The light guide plate serves to guide the light incident from the light source to the upper sheet. The light guide plate may have a three-dimensional structure on one side or both sides of the light guide plate so that the light incident from the light source reaches the entire plane of the light guide plate, have.

Various methods for forming a three-dimensional structure on one side or both sides of the light guide plate have been proposed in this case. Japanese Laid-Open Patent Publication No. 2009-043565 discloses a method of forming a pattern by applying a photocurable resin on a substrate and bringing the master into close contact with the resin surface.

When a pattern is formed by such an imprint technique, there is a possibility that peeling between the base layer and the pattern layer may occur due to insufficient adhesion with the base layer.

A problem to be solved by the present invention is to provide a light guide film in which adhesion between a base layer and an optical pattern layer is enhanced.

Another problem to be solved by the present invention is to provide a light guiding film which does not cause delamination and has no optical property loss and has excellent brightness.

A light guide film of one aspect of the present invention includes a substrate layer; An optical pattern layer formed on the base layer, and an adhesion promoting layer formed between the base layer and the optical pattern layer, and the ΔHaze value represented by the following formula 1 may be 0.3 or less.

<Formula 1>

ΔHaze = Hp-Hs

In the above equation, Hs is the haze value only for the base layer, and Hp is the haze value for the state in which the adhesion increasing layer is formed on the base layer.

Another aspect of the present invention is a light guide film comprising a base layer; An adhesion promoting layer formed between the substrate layer and the optical pattern layer, wherein the adhesion promoting layer is formed of a composition comprising a photo-curing resin and a solvent, The solvent may include a solvent capable of dissolving the substrate layer and a solvent not dissolving the substrate layer in a weight ratio of 2: 8 to 8: 2.

A backlight unit according to another aspect of the present invention includes: the light guide film; And a light collecting sheet disposed on the light guide film and having an inverted prism formed thereon.

The liquid crystal display device according to another aspect of the present invention may include the backlight unit.

The adhesive force between the base layer and the optical pattern layer is enhanced in the light guide film of the present invention, so that delamination can not occur.

The light-guiding film of the present invention does not cause delamination between layers, and has no loss in optical characteristics and is excellent in luminance.

1 is a schematic cross-sectional view of a light guide film according to an embodiment of the present invention.
2 is a cross-sectional schematic diagram of a light guide film according to another embodiment of the present invention.
3 is a cross-sectional schematic diagram of a backlight unit according to an embodiment of the present invention.
4 is a cross-sectional schematic diagram of a liquid crystal display device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings. However, the techniques disclosed in this application are not limited to the embodiments described herein but may be embodied in other forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the widths and thicknesses of components are slightly enlarged in order to clearly illustrate each component. In addition, although only a part of the components is shown for convenience of explanation, those skilled in the art can easily grasp the rest of the components. 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 and scope of the invention.

The terms "upper" and "lower" in this specification are defined with reference to the drawings, wherein "upper" may be changed to "lower", "lower" What is referred to as "on" may include not only superposition, but also intervening other structures in the middle. On the other hand, what is referred to as "directly on" or "directly above"

As used herein, "(meth) acrylic" may mean "acrylic" and / or "methacrylic".

Hereinafter, a light guide film according to an embodiment of the present invention will be described with reference to FIG. 1 is a schematic view showing a cross section of a light guide film according to an embodiment of the present invention. A light guide film 100 according to an embodiment of the present invention includes a base layer 110, an optical pattern layer 120 formed on the base layer 110, and an optical pattern layer 120 And an adhesion promoting layer 130 formed between the adhesion promoting layer 130 and the adhesion promoting layer 130.

The refractive index difference between the two kinds of the base layer 110, the optical pattern layer 120, and the adhesion promoting layer 130 may be 0.02 or less in the light guide film 100 of the present embodiment. The adhesion between the base layer 110, the optical pattern layer 120, and the adhesion promoting layer 130 is enhanced within the above range, and the brightness can be excellent.

The light guide film 100 of the present embodiment may have an internal haze (DELTA Haze) value represented by the following formula 1 of 0.3 or less, specifically 0.01 to 0.1. If the internal haze value exceeds the above range, the luminance loss may be large and the transparency may be degraded.

<Formula 1>

ΔHaze = Hp-Hs

In the above equation, Hs is the haze value only for the base layer, and Hp is the haze value for the state in which the adhesion increasing layer is formed on the base layer.

The interface between the substrate layer 110 and the adhesion promoting layer 130 is fused without forming a fine concavo-convex shape, so that the adhesive force is excellent, and the adhesion between the substrate layer 110 and the adhesion layer The enhancement layer 130 is integrated.

The base layer 110 supports the optical pattern layer 120 and guides light incident from the light source to emit light to an upper sheet (not shown) of the light guide film. The upper surface of the base layer 110 is a light exit surface, the lower surface is a surface on which light is incident from the second optical pattern layer, and the side surface may be a surface from which light is incident from a light source (not shown).

The base layer 110 has a refractive index equal to or greater than the refractive index of the optical pattern layer 120 and / or the adhesion promoting layer 130 so that light incident from the light source can not be reflected and emitted only in the light guide plate, can do. The refractive index difference between the base layer 110 and the optical pattern layer 120 and / or the adhesion promoting layer 130 may be 0.02 or less. It is possible to increase the light emission rate within the above range and to prevent the luminance reduction.

The base layer 110 may be formed of a resin having a refractive index of 1.48 or more, specifically 1.55 to 1.65. For example, it may be formed of a resin such as polycarbonate or polymethyl (meth) acrylate. When polymethyl (meth) acrylate is used, it is more advantageous for thinning, but is not limited thereto.

The haze of the base layer 110 at a wavelength of 380 nm to 780 nm may be 0.06% or less.

The thickness of the base layer 110 may be 200 占 퐉 to 800 占 퐉, for example, 400 占 퐉 to 600 占 퐉, and may be used in a thin optical display device within the above range.

The optical pattern layer 120 is formed on at least one surface of the base layer 110, and may include an optical pattern to guide and diffuse or condense the incident light.

The difference in refractive index between the optical pattern layer 120 and the adhesion promoting layer 130 may be 0.05 or less, specifically 0.02 or less. It is possible to provide a light guide film in which the adhesive force is increased within the above range without loss of optical characteristics. The refractive index of the optical pattern layer 120 may be 1.48 or more, specifically 1.55 to 1.65.

The optical pattern layer 120 may comprise a photocurable resin. Specifically, the adhesion promoting layer 130 may be formed by coating a photocurable resin on the adhesion promoting layer 130 and forming a pattern by an imprinting method.

The photocurable resin may be a high refractive index resin having a refractive index of 1.48 or more, specifically 1.55 to 1.65. The luminance reduction can be prevented within the above range.

 The photo-curing resin may be a (meth) acrylic resin, a polycarbonate resin, a styrene resin, an olefin resin, a polyester resin, or a combination thereof. Examples thereof include high refractive index aromatic urethane acrylate, Acrylate, aromatic ethoxylated bisphenol acrylate, or combinations thereof.

The optical pattern layer 120 may be formed of a composition containing a photocurable resin and may be a solventless composition to form a pattern by an imprint technique.

The optical pattern layer 120 is formed of a lenticular lens pattern, a prism pattern having a triangular section, a prism pattern having a polygonal section (n is an integer of 4 to 10), a prism pattern formed on a curved surface at the top, Patterns, dot patterns, or combinations thereof.

The adhesion promoting layer 130 may be formed between the base layer 110 and the optical pattern layer 120 to enhance adhesion between the base layer 110 and the optical pattern layer 120.

The adhesion enhancement layer 130 may have a difference in refractive index from the optical pattern layer 120 to 0.05 or less, specifically 0.02 or less. It is possible to provide a light guide film in which the adhesive force is increased within the above range without loss of optical characteristics. The refractive index of the adhesion promoting layer 130 may be 1.48 or more, specifically 1.55 to 1.65.

The adhesion promoting layer 130 may include a photo-curing resin. Specifically, it may be a high refractive index resin having a refractive index of 1.48 or more, specifically 1.55 to 1.65. The luminance reduction can be prevented within the above range.

The photocurable resin may be a (meth) acrylic resin, a polycarbonate resin, a styrene resin, an olefin resin, a polyester resin, or a combination thereof. The adhesive force enhancement layer 130 may be integrated with the optical pattern layer 120 using the same photocurable resin as that of the photocurable resin of the optical pattern layer 120 to improve adhesion, The haze value is low and there is no luminance loss. Furthermore, there is no difference in refractive index through the use of the same resin, so that there is no deterioration in optical characteristics.

The adhesion promoting layer 130 may be formed of a composition for the adhesion promoting layer including the photo-curing resin and the solvent. The photo-curable resin is as described above, and the adhesion to the base layer 110 can be further enhanced by using a solvent.

The composition for the adhesion-promoting layer may comprise a solvent. The solvent dissolves a part of the base layer 110 to fuse the base layer 110 and the adhesion promoting layer 130 at the interface so that the adhesion between the base layer 110 and the adhesion promoting layer 130 can be remarkably improved Can play a role.

The solvent may include a first solvent capable of dissolving the substrate layer 110 and a second solvent not dissolving the substrate layer 110.

Examples of the first solvent capable of dissolving the base layer 110 include ketone solvents such as acetyl acetone, methyl ethyl ketone and methyl isobutyl ketone, and organic solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl butyrate, methyl benzoate And hydrocarbon solvents such as benzene, chlorobenzene and toluene. These solvents may be used singly or in combination of two or more.

The second solvent that does not dissolve the base layer 110 is an alcohol solvent such as ethanol, isopropanol, n-propanol, isobutyl alcohol, hexanol, and benzyl alcohol, diisopropyl ether, propylene glycol methyl ether, , An ether solvent such as dioxane, Carboxylic acid solvents such as formic acid, acetic acid, propionic acid, valeric acid and benzoic acid; and amine solvents such as ethylenediamine, aniline, pyridine and methylpyridine. These solvents may be used singly or in combination.

The solvent capable of dissolving the base material layer 110 and the solvent not dissolving the base material layer 110 may be contained in a ratio of 2: 8 to 8: 2 by weight of the second solvent: first solvent, For example, from 2: 8 to 7: 3. Within this range, the haze can be low and the adhesion force can be excellent.

The solvent may be contained in an amount of 90% by weight to 50% by weight, specifically 80% by weight to 60% by weight, based on the total weight of the composition for the adhesion promoting layer. can do.

The substrate layer 110 including the solvent is fused at the interface with the adhesion promoting layer 130 and the fine irregularities occurring at the interface where different components are fused are reduced so that the adhesion force can be enhanced without loss of optical properties.

The composition for the adhesion-promoting layer may further include an initiator. The initiator may be a photopolymerization initiator, such as a ketone-based, phosphine oxide-based, phosphorus-based, triazine-based, acetophenone based, benzophenone based or the like.

The adhesion promoting layer 130 may have a thickness of 1 탆 or less, specifically 0.8 탆 to 0.1 탆. Within the above range, it can be advantageous to improve adhesion and maintain optical characteristics, and it is applicable to thin display devices within the above range.

Hereinafter, a light guide film according to another embodiment of the present invention will be described with reference to FIG. 2 is a schematic view showing a section of a light guide film of another embodiment of the present invention. The light guide film according to this embodiment includes a base layer 110, a first optical pattern layer 121 formed on the base layer 110, and a second optical pattern layer 121 formed between the base layer 110 and the first optical pattern layer 121 A second optical pattern layer 122 formed below the base layer 110 and a second optical pattern layer 122 formed between the base layer 110 and the second optical pattern layer 122. The first adhesion- The second adhesion promoting layer 132 may be formed.

The description is the same as that of the light guide film according to the embodiment of the present invention except that the adhesive force enhancement layer and the optical pattern layer are respectively formed on the upper and lower portions of the base layer,

The first optical pattern layer 121 is formed on an upper portion of the base layer 110 and includes light emitted from the upper portion of the base layer 110 including the first optical pattern and incident on the first optical pattern layer 121 And then emitted onto the first optical pattern layer 121. Specifically, the first optical pattern layer 121 serves to guide the incident light to the emission surface and diffuse it.

The first optical pattern layer 121 may include a first optical pattern, and the first optical pattern may include an optical pattern having at least one curved surface formed at its top. For example, the first optical pattern may include a lenticular lens pattern, a prism pattern formed on a curved surface at the top, a microlens pattern, an emboss pattern, or a combination thereof.

The thickness of the first optical pattern layer 121 may be 50 탆 to 5 탆, for example, 30 탆 to 10 탆, and may be used in a thin optical display device within the above range.

The first optical pattern layer 121 may include a photocurable resin, and the photocurable resin is the same as that described with respect to the light guide film according to the embodiment of the present invention.

The first adhesion promoting layer 131 may be formed between the base layer 110 and the first optical pattern layer 121 to enhance adhesion between the base layer 110 and the first optical pattern layer 121 And specific details are the same as those described for the light guide film according to one embodiment of the present invention.

The second optical pattern layer 122 is formed on the other surface of the base layer 110 and reflects light incident from a light source (not shown) including the second optical pattern, It is a part of gathering so that it does not scatter.

The second optical pattern layer 122 includes a second optical pattern, and the second optical pattern includes a lenticular lens pattern, a prism pattern having a polygonal cross section (n is an integer of 4 to 10), a micro lens pattern, Pattern, dot pattern, or a combination thereof.

The second optical pattern layer 122 may include a photocurable resin, and the photocurable resin is the same as that described with respect to the light guide film according to the embodiment of the present invention.

The thickness of the second optical pattern layer 122 may be 100 탆 to 5 탆, for example, 50 탆 to 10 탆, and may be used in a thin optical display device within the above range.

The second adhesion promoting layer 132 may be formed between the base layer 110 and the second optical pattern layer 1221 to enhance adhesion between the base layer 110 and the second optical pattern layer 122 And specific details are the same as those described for the light guide film according to one embodiment of the present invention.

Hereinafter, a method of manufacturing a light guide film according to an embodiment of the present invention will be described. In the method of manufacturing a light guide film according to the present embodiment, an optical pattern can be formed by imprinting using a mold, and a thin light guide film can be manufactured through the imprint method.

The method of manufacturing a light guide film according to the present embodiment may include the step of forming an adhesion promoting layer on at least one side of the substrate layer. Specifically, the step of forming the adhesion-promoting layer may include applying the adhesion-promoting layer composition to at least one surface of the substrate layer, and curing the composition by irradiating ultraviolet light.

Forming the adhesion-promoting layer, and forming an optical pattern layer including an optical pattern on the adhesion-promoting layer. Specifically, the step of forming the optical pattern layer may be performed by applying a photo-curable resin to the adhesion promoting layer, transferring the optical pattern using a mold having a pattern formed on the base layer coated with the photo-curable resin, irradiating ultraviolet rays, And curing the resin.

The step of forming the adhesion-promoting layer on at least one side of the base layer may include the steps of forming a first adhesion-promoting layer on one side of the base layer and a second adhesion-promoting layer on the other side of the base layer, The formation of the first adhesion-promoting layer and the formation of the second adhesion-promoting layer may be performed sequentially, in reverse order, or simultaneously.

The step of forming an optical pattern layer including an optical pattern on the adhesion promoting layer may include forming a first optical pattern layer on the first adhesion promoting layer and forming a second optical pattern layer on the second adhesion promoting layer , And the formation of the first optical pattern layer and the formation of the second optical pattern layer may be performed sequentially, in reverse order, or simultaneously.

The mold having the pattern is formed with an optical pattern to be transferred to the optical pattern layer. The optical pattern formed on the mold includes the first optical pattern described with respect to the light guide film according to the embodiment of the present invention, .

The composition for the adhesion-promoting layer, the photo-curing resin and the base layer are as described for the light guide film according to one embodiment of the present invention.

The ultraviolet ray curable resin to which the optical pattern is transferred can be cured by irradiating ultraviolet rays.

The total light amount of the ultraviolet ray irradiation may be 500 mJ / cm 2 to 2000 mJ / cm 2, and curing is sufficiently progressed within the above range, and yellowing can be prevented.

Hereinafter, a backlight unit according to an embodiment of the present invention will be described with reference to FIG. 3 is a cross-sectional view of a backlight unit according to an embodiment of the present invention.

3, a backlight unit 400 according to an embodiment of the present invention includes a light source 301, a light guide film 302 for guiding light incident from the light source 301, A reflective sheet 303 and a light collecting sheet 304 disposed on the upper portion of the light guide film 302 and formed with an inverted prism. The light guide film 302 may include a light guide film according to the embodiments of the present invention.

The light source 301 generates light, and various light sources such as a linear light source lamp, a planar light source lamp, a CCFL, or an LED may be used. A light source cover (not shown in FIG. 8) may be further formed on the outside of the light source for the purpose of protecting the light source. The position of the light source 301 in the backlight unit is not limited, but may be an edge-type backlight unit disposed on the side surface of the light guide film 302.

The light guide film 302 may serve to guide the light incident from the light source to the prism sheet.

The reflective sheet 303 may reflect the light generated from the light source and enter the light guide film again to improve the light efficiency.

The light collecting sheet 304 on which the inverse prism is formed collects the light incident from the light guide film and supplies it to the optical sheet.

Although not shown in FIG. 3, one or more protective sheets, a diffusion sheet, and the like may be further formed on the light collecting sheet 304 on which the inverted prisms are formed. Although not shown in FIG. 3, a polarizing plate may be positioned directly above the light-converging sheet 304 on which an inverse prism is formed. The polarizing plate may include a polarizer, a protective film formed on at least one surface of the polarizer, or a retardation film.

Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIG. 4 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

4, a liquid crystal display 400 according to an exemplary embodiment of the present invention includes a liquid crystal display panel 401, a polarizing plate 402 formed on the upper and lower surfaces of the liquid crystal display panel 401 And a backlight unit 403 formed on the lower portion of the liquid crystal display panel 401. The backlight unit 403 may include a backlight unit of an embodiment of the present invention.

The LCD panel 401 includes a liquid crystal panel including a liquid crystal cell layer sealed between a first substrate and a second substrate. The liquid crystal cell layer includes a VA (Vertical Alignment) mode, an IPS a fringe field switching mode, a twisted nematic (TN) mode, and the like.

The polarizing plate 402 may include a polarizer and a protective film and / or a retardation film formed on the polarizer. FIG. 4 shows that the same polarizing plate is formed on the upper and lower surfaces of the liquid crystal display panel, but different types of polarizing plates may be formed on the upper and lower surfaces, respectively, with polarizers, protective films, and retardation films.

Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to examples, comparative examples and test examples. However, these examples, comparative examples and test examples are provided for illustrative purposes only in order to facilitate understanding of the present invention, and the scope and scope of the present invention are not limited by the following examples, comparative examples and test examples.

Production Example 1: Preparation of composition for adhesion-promoting layer

2 g of isopropanol: methyl isobutyl ketone in a weight ratio of 2: 3 and 0.01 g of Irgacure 184 (BASF) as an initiator were mixed to obtain a composition for adhesion-promoting layer of Production Example 1, .

Preparation Example 2: Preparation of composition for adhesion-promoting layer

2 g of a photo-curable resin (Uvicx 581, Polynetron Co., refractive index: 1.581), 6 g of a solvent having a weight ratio of isopropanol: methyl isobutyl ketone of 1: 4 and 0.01 g of Irgacure 184 (BASF) as a initiator were mixed to prepare a composition for adhesion- .

Preparation Example 3: Preparation of composition for adhesion-promoting layer

2 g of a photo-curable acrylic resin (Uvicx 581, Polynetron; refractive index 1.581), 6 g of a 4: 2 weight ratio propylene glycol methyl ether: methyl ethyl ketone and 0.01 g of Irgacure 184 (BASF) as a initiator were mixed, A composition was prepared.

Preparation Example 4: Preparation of composition for adhesion-promoting layer

2 g of a solvent having a weight ratio of isopropanol: methyl isobutyl ketone of 2: 3 and 0.01 g of Irgacure 184 (BASF) as an initiator were mixed to obtain an adhesion-promoting layer of Production Example 4 A composition was prepared.

Preparation Example 5: Preparation of composition for adhesion-promoting layer

2 g of acrylic photopolymerizable resin (Uvicx 581, Polynetron; refractive index 1.581), 6 g of methyl isobutyl ketone as solvent, and 0.01 g of Irgacure 184 (BASF) as initiator were mixed to prepare a composition for adhesion-promoting layer of Production Example 5.

Production Example 6: Preparation of composition for adhesion-promoting layer

2 g of a photo-curable resin (Uvicx 581, Polynetron Co., refractive index: 1.581), 6 g of a solvent having a weight ratio of isopropanol to methyl isobutyl ketone of 1: 9 and 0.01 g of Irgacure 184 (BASF) as a initiator were mixed to prepare a composition for adhesion- .

Example 1

The adhesion-promoting layer composition of Production Example 1 was coated on one surface of a polycarbonate base film (I-component yarn, thickness 500 탆, refractive index 1.59) and cured by irradiation with ultraviolet rays at 300 mJ / cm 2 to form a 0.5 탆 thick adhesion- . (Uvicx 581, manufacturer; refractive index: 1.581) was applied to the formed adhesion-promoting layer, and a prism pattern having the same height of 10.1 占 퐉, a pitch of 13 占 퐉 and a vertex angle of 65.5 占 was cut into a triangular- And irradiated with ultraviolet rays at 300 mJ / cm &lt; 2 &gt; (Uvicx 581, manufacturer; refractive index: 1.581) was applied to the adhesion enhancing layer in the same manner as described above, and a film having a diameter of 30 탆, a height of 2 탆, an aspect ratio of 0.067, and a curvature radius of 57 탆 The lenticular lens pattern was laminated with a knitted pattern mold, and irradiated with ultraviolet rays at 300 mJ / cm &lt; 2 &gt;

Example 2

A light-guiding film was prepared in the same manner as in Example 1, except that the adhesion-promoting layer composition of Production Example 2 was used instead of the production of Example 1.

Example 3

A light-guiding film was prepared in the same manner as in Example 1, except that the adhesion-promoting layer composition of Production Example 3 was used instead of the production of Example 1.

Example 4

(PZPC5503, manufactured by NC-Chem, refractive index: 1.5503) instead of acrylic-based photo-curing resin (Uvicx581, manufacturer: refractive index 1.581) was used instead of the composition for adhesion- A light-guiding film was prepared in the same manner as in Example 1, except that it was used.

Comparative Examples 1 to 2

A light-guiding film was prepared in the same manner as in Example 1, except that the adhesion-promoting layer composition of Production Examples 5 to 6 was used instead of Production Example 1, respectively.

The following properties of the light guide films of Examples and Comparative Examples were evaluated.

(1) Haze (%): Haze was measured using a haze meter (NDH2000, manufactured by NIPPON DENSHOKU) at a wavelength of 350 nm to 780 nm in accordance with JIS 7105. The haze (Hs) of only the base film used in Examples and Comparative Examples and the haze (Hp) in the state where only the adhesion enhancing layer was formed on one side of the base film were measured and the internal haze value Respectively.

ΔHaze = Hp-Hs

(2) Adhesion force: The prism pattern side of the light guide film is cut with a cutter knife in a unit of 1 mm x 1 mm to produce 100 cells. Attach the tape (Nichiban No. 405 adhesive tape) and peel the tape after 5 minutes. The number of remaining cells among 100 cells is counted. The case where the number of remaining cells was 100 or more, the case where the number of remaining cells was 99, the case where the number of the cells was 99 to 51, and the case where the number was 50 or less.

(3) Relative luminance: Reflective film (3M ESR), light guide plate (SDI company, L-806T-MT01) and reverse prism (SDI company, I-Prism13P) were attached to an 8 inch BLU (MT330KKAA47A) And the luminance (G1) was measured using EZcontrast (Eldim). The composite optical sheet prepared in Example and Comparative Example was attached to the backlight unit instead of the light guide film, and the luminance (G2) was measured by the same method. The relative luminance was calculated by G2 / G1 x 100.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Base film Haze (%) 0.05 0.05 0.05 0.05 0.05 0.05 Adhesion promoting layer Haze (%) 0.07 0.13 0.09 0.1 0.82 0.53 ΔHaze 0.02 0.08 0.04 0.05 0.77 0.4 Refractive index of base film 1.59 1.59 1.59 1.59 1.59 1.59 Adhesion enhancing layer refractive index 1.61 1.61 1.61 1.594 1.61 1.61 Refractive index of optical pattern layer 1.61 1.61 1.61 1.594 1.61 1.61 Adhesion ○ ○ ○ ○ ○ ○ Relative luminance 1.55 1.50 1.53 1.6 1.3 1.42

From the results shown in Table 1, it can be seen that the light-guiding film of the example is excellent in adhesion so that delamination does not occur between layers, and the luminance is 1.5 times or more higher than that of the conventional light-guiding film.

Claims (20)

A base layer;
An optical pattern layer formed on the base layer, and
And an adhesion promoting layer formed between the base layer and the optical pattern layer,
A light guide film having a haze value of not more than 0.3,
<Formula 1>
ΔHaze = Hp-Hs
Where Hs is the haze value only for the base layer and Hp is the haze value for the state in which the adhesion increasing layer is formed on the base layer,
Wherein the difference in refractive index between the two of the base layer, the optical pattern layer and the adhesion promoting layer is 0.02 or less. The method according to claim 1,
Wherein the base layer comprises a polycarbonate resin or a polymethyl (meth) acrylate resin. The method according to claim 1,
Wherein a difference in refractive index between the adhesion promoting layer and the base layer is 0.02 or less. The method according to claim 1,
Wherein the refractive index difference between the optical pattern layer and the base layer is 0.02 or less. The method according to claim 1,
Wherein the adhesion promoting layer is formed of a composition comprising a photo-curable resin and a solvent. 6. The method of claim 5,
Wherein the solvent comprises a solvent capable of dissolving the base layer and a solvent not dissolving the base layer in a weight ratio of 2: 8 to 8: 2. The method according to claim 6,
The solvent capable of dissolving the base layer is a ketone solvent, an ester solvent, a hydrocarbon solvent or a combination thereof,
The solvent that does not dissolve the base layer is an alcohol solvent, an ether solvent, a carboxylic acid solvent, an amine solvent, or a combination thereof. 6. The method of claim 5,
Wherein the photo-curing resin includes a (meth) acrylic resin, a polycarbonate resin, a styrene resin, an olefin resin, a polyester resin or a combination thereof. The method according to claim 1,
Wherein the optical pattern layer is formed of a composition comprising a photocurable resin. 10. The method of claim 9,
Wherein the composition does not include a solvent. The method according to claim 1,
Wherein the optical pattern layer and the adhesion-enhancing layer comprise the same photo-curing resin. 10. The method of claim 9,
Wherein the photo-curable resin comprises a high-refractive index aromatic urethane acrylate, an aromatic polypyrrole-based acrylate, an aromatic ethoxylated bisphenol-based acrylate or a combination thereof. The method according to claim 1,
Wherein the optical pattern includes at least one of a lenticular lens pattern, a prism pattern, a micro lens pattern, an emboss pattern, and a dot pattern. The method according to claim 1,
Wherein the optical pattern layer includes a first optical pattern layer formed on the base layer and a second optical pattern layer formed on the bottom of the base layer,
Wherein the adhesion enhancing layer comprises a first adhesion promoting layer formed between the base layer and the first optical pattern layer and a second adhesion promoting layer formed between the base layer and the second optical pattern layer. delete delete delete A light guide film; And
And a light converging sheet disposed on the light guide film and formed with an inverted prism,
Wherein the light guide film comprises the light guide film of any one of claims 1 to 14. 19. The method of claim 18,
And a polarizing plate on the light converging sheet on which the reverse prism is formed. A liquid crystal display device comprising the backlight unit of claim 18.

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