KR20160053257A - Composite optical sheet, method for prepaing the same and optical display apparatus comprising the same - Google Patents

Abstract

The present invention relates to a composite optical sheet, a method for preparing the same, and an optical display apparatus comprising the same. The composite optical sheet according to the present invention comprises: a first optical sheet; a second optical sheet; and an adhesive layer, located between the first optical sheet and the second optical sheet, for integrating the first optical sheet and the second optical sheet. The second optical sheet includes: a second optical pattern having an average height of H; and fine protrusions formed on the surface of the second optical pattern, wherein the fine protrusions are formed from the bottommost side only to a surface less than or equal to 0.65H. Thus, the composite optical sheet according to the present invention can have less Newton′s rings and minimize brightness loss.

Description

TECHNICAL FIELD The present invention relates to a composite optical sheet, a method of manufacturing the same, and an optical display device including the composite optical sheet. [0002]

The present invention relates to a composite optical sheet, a method of manufacturing the same, and an optical display device including the composite optical sheet.

The backlight unit may include a light source such as a light emitting diode or a fluorescent lamp, a light guide plate, a prism sheet, a diffusion sheet, a protective sheet, or the like. Recently, attempts have been made to thin backlight units.

In the composite optical sheet, two optical sheets having optical patterns formed on one surface of the base film are integrated with an adhesive layer, and it is effective to thin the backlight unit. However, a luminance loss may occur due to a wicking phenomenon caused by the adhesive layer, and a sheet-like problem has been caused by the thinning of the base film in recent composite optical sheets. Further, in a specific product group to which a composite optical sheet is applied, for example, a tablet or a mobile product, a Newton's ring phenomenon occurs due to a decrease in the pitch of the optical pattern, . The background art of the present invention is disclosed in Korean Patent Publication No. 2013-0064404.

A problem to be solved by the present invention is to provide a composite optical sheet in which the Newton ring phenomenon is relaxed.

Another problem to be solved by the present invention is to provide a composite optical sheet that minimizes luminance loss and has no sheet peeling.

Another object to be solved by the present invention is to provide a composite optical sheet which can be manufactured by a simple manufacturing process, has high adhesive force between two optical sheets, mitigates Newton ring phenomenon, minimizes luminance loss, .

The composite optical sheet of the present invention includes a first optical sheet, a second optical sheet, and an adhesive layer positioned between the first optical sheet and the second optical sheet and integrating the first optical sheet and the second optical sheet , The second optical sheet includes a second optical pattern having an average height H and fine protrusions formed on a surface of the second optical pattern, and the fine protrusions are formed on a surface of 0.65H or less from the lowermost surface of the second optical pattern Respectively.

A method for producing a composite optical sheet of the present invention comprises the steps of providing a first optical sheet and forming a second optical sheet having an optical pattern formed on one surface of a mold having a depressed portion for an optical pattern having an intrinsic height H, And integrating the first optical sheet with the first optical sheet, wherein the depressions for forming the fine protrusions are formed on the surface of the optical patter for only 0.65H or less from the lowermost surface.

The optical display device of the present invention may include the composite optical sheet.

The present invention provides a composite optical sheet in which the Newton ring phenomenon is relaxed.

The present invention provides a composite optical sheet that minimizes luminance loss and has no sheet peeling.

The present invention provides a composite optical sheet which can be manufactured by a simple manufacturing process, has high adhesion between two optical sheets, minimizes Newton ring phenomenon, luminance loss, and does not cause sheet fogging.

1 is a perspective view of a composite optical sheet according to an embodiment of the present invention.
Fig. 2 is a partial cross-sectional view of the I-1 'axis of the first optical sheet of Fig. 1;
3 is a cross-sectional view taken along line II-II 'of FIG.
4 is a cross-sectional view of a mold used in the manufacturing method of an embodiment of the present invention.
5 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

Embodiments of the present application will now be described in more detail with reference to the accompanying drawings. However, the techniques disclosed in the present application are not limited to the embodiments described herein but may be embodied in other forms. It should be understood, however, that the embodiments disclosed herein 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 width, thickness, and the like of the components are enlarged in order to clearly illustrate the components of each device. 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 is to be understood that when an element is described above as being located above or below another element, it is to be understood that the element may be directly on or under another element, It means that it can be done. 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. In the drawings, the same reference numerals denote substantially the same elements.

The terms " upper "and" lower "are defined with reference to the drawings, 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" means acrylic and / or methacrylic.

Hereinafter, a composite optical sheet according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view of a composite optical sheet according to an embodiment of the present invention, FIG. 2 is a partial cross-sectional view of the first optical sheet of FIG. 1 taken along line I-I ' to be.

The composite optical sheet 100 according to an embodiment of the present invention may include a first optical sheet 110, a second optical sheet 120, and an adhesive layer 130. Referring to FIGS. 1 and 2, a composite optical sheet 100 according to an embodiment of the present invention includes at least one fine protrusion 123 to improve Newton's ring phenomenon caused by the use of the adhesive layer 130 can do. Particularly, the phenomenon of Newton ring can be remarkably improved when used in a mobile product or a tablet product in which the pitch of the optical pattern is small.

The first optical sheet 110 is located below the second optical sheet 120 and has a light exit surface serving as a top surface and a light incident surface serving as a bottom surface, The first optical sheet 110 may include a first base film 111 and a first optical pattern 112 formed on the first base film 111.

The first base film 111 supports the first optical sheet 110 and is not limited in thickness but may be in the range of 35 to 300 탆. The first base film 111 can support the first optical sheet in this range, Lt; / RTI > The first base film 111 is formed of an optically transparent thermoplastic resin or a composition containing the thermoplastic resin. The thermoplastic resin may be a polyester resin including a polyethylene terephthalate resin, a polyethylene naphthalate resin, a polyacetal resin, a (meth) acrylic Non-cyclic polyolefin resins including polycarbonate resins, styrene resins, vinyl resins, polyphenylene ether resins, polyethylene, and polypropylene, cycloolefin resins, acrylonitrile-butadiene-styrene copolymer resins, A polyacrylate resin, a polyaryl sulfone resin, a polyethersulfone resin, a polyphenylene sulfide resin, or a fluorine resin, and these may be used singly or in combination of two or more.

The first optical pattern 112 is formed on the upper surface of the first base film 111, and the incident light incident from the lower surface of the first optical pattern 112 is condensed to increase the brightness. 1 and 3 illustrate a case where the first optical pattern 112 is a prism having a triangular section, but the present invention is not limited thereto, and a prism having a polygonal shape (a polygon having a number of sides of 4 to 10) have.

The first optical pattern 112 may penetrate the adhesive layer 130. The ratio of the average penetration depth of the adhesive layer 130 of the first optical pattern 112 to the average height of the first optical pattern 112 may be 0.01 to 0.2. The above-mentioned "average penetration depth of the adhesive layer of the first optical pattern" can be B / N when the total number of the first optical patterns is N and the total sum of penetration depths of the adhesive layers of the first optical pattern is B, "Penetration" means that the apex of the first optical pattern penetrates into the adhesive layer through the adhesive layer and the vertex of the first optical pattern exists inside the adhesive layer, and the "vertex" means that the height of the first optical pattern Quot; penetration depth "means a vertical length at which the apex of the first optical pattern penetrates into the adhesive layer.

Referring to FIG. 3, the height H1 of the first optical pattern 112 may be 10 to 30 μm, specifically 10 to 25 μm, and the pitch P1 may be 10 to 50 μm, And the apex angle alpha 1 may be 80 [deg.] To 100 [deg.]. The luminance may be improved in the above range. 1 and 3 show a composite optical sheet having the same height, width, and pitch, respectively, of the neighboring first optical patterns, but the height, width, or pitch of the neighboring first optical patterns may be different from each other.

The first optical pattern 112 may be formed of a composition for forming a first optical pattern including an ultraviolet curable unsaturated compound and an initiator or the like or may be formed of the same or different materials among the materials for the first base film. As an example, the ultraviolet ray-curable unsaturated compound is a resin, an oligomer, a monomer, or a mixture thereof having a refractive index of 1.5 to 1.7, and specifically includes a fluorene derivative unsaturated resin, an epoxy (meth) acrylate, a urethane (meth) (Meth) acrylate, phenoxybenzyl (meth) acrylate, phenylphenoxyethyl (meth) acrylate, ethoxylated thiodiphenyl di (Meth) acrylate, phenylthioethyl (meth) acrylate monomer, or oligomers thereof, but are not limited thereto. The initiator may be a photopolymerization initiator, such as a ketone-based, phosphine oxide-based, or the like, but is not limited thereto.

The second optical sheet 120 is formed on the upper surface of the first optical sheet 110 and has a light incident surface that is a top surface and a light incident surface that is a bottom surface and changes the path of light incident from the first optical sheet 110 . The second optical sheet 120 includes a second base film 121, a second optical pattern 122 formed on the second base film 121, and fine protrusions (not shown) protruding from the surface of the second optical pattern 122 123).

Referring to FIG. 2, when the average height of the second optical pattern 122 is H, the fine protrusions 123 extend from the lowest surface 122a (the surface at 0H) of the second optical pattern 122 to 0.65H or less Specifically, 0.35H or less, more specifically 0.1H to 0.35H. Accordingly, by changing the path of the light incident from the first optical sheet 110 and diffusing the light, Newton's ring phenomenon due to use of the adhesive layer can be improved. In particular, the Newton ring phenomenon can be remarkably improved when used in a mobile product or a tablet product in which the pitch of the second optical pattern 122 is small. In addition, the fine protrusions 123 increase the surface area of the second optical pattern in which the fine protrusions 123 are not formed, thereby enhancing the diffusion and condensing effect of the composite optical sheet.

In the present specification, "average height" means the sum of the heights of the patterns divided by the total number of the patterns. 1 and 2, the height of the second optical pattern is the same, so that the average height and height of the second optical pattern may be the same.

In addition, since the fine protrusions 123 are not formed in the region from the apex portion of the second optical pattern 122 to 0.65H, the apex portion of the second optical pattern can substantially maintain the shape, thereby preventing the luminance loss. The "vertex" means a portion at the top when the lowest one of the second optical patterns is a base.

The fine protrusions 123 may have a diffusion effect by including one or more curved surfaces. 2 illustrates fine protrusions 123 having a semi-elliptical cross section, but the present invention is not limited thereto, and the cross section may be a semicircular, semi-elliptical or semi-circular deformed shape.

The fine protrusions 123 have a smaller size than the second optical pattern 122 so that the effect of improving the Newton ring phenomenon and suppressing the luminance loss can be realized without affecting the second optical pattern 122. [ Specifically, the ratio (S2 / P2) of the width S2 of the fine protrusion 123 to the pitch P2 of the second optical pattern 122 may be 0.001 to 0.01, and the ratio of the width S2 of the second optical pattern 122, The ratio S1 / H of the height S1 of the fine protrusion 123 to the height H of the protrusion 123 may be 0.001 to 0.01. Within this range there may be a Newton ring reduction effect. The fine protrusion 123 may have a height S1 of 1 占 퐉 to 3 占 퐉 and a width S2 of 2 占 퐉 to 6 占 퐉 and may have a Newton ring reducing effect in the above range.

2, the fine protrusions 123 may be formed uniformly or nonuniformly in the second optical pattern 122, and the height and / or width of the fine protrusions 123 are different from each other. However, The height and / or width of the protrusions 123 may be equal to each other.

The fine protrusions 123 may be formed of the same or different composition as the composition forming the second optical pattern 122 or may be formed of the same or different materials among the materials for the second base film 121.

The second base film 121 supports the second optical sheet 120 and is not limited in thickness, but may be in the range of 35 to 300 탆. The thickness of the second base film 121 may be equal to or different from the thickness of the first base film. The second base film 121 may be formed of the same or different materials for the first base film 111.

The second optical pattern 122 is a pattern for changing the path of light incident from the first optical sheet 110. Figs. 1 and 2 show a case where the second optical pattern 122 is a triangular prism pattern However, the present invention is not limited thereto, and a prism whose polygonal cross-section is a polygon having 4 to 10 sides may also be included.

The longitudinal direction of the second optical pattern 122 and the longitudinal direction of the first optical pattern 112 form an angle of a predetermined range, specifically, an angle of 85 to 95 degrees, thereby preventing pitch moire generated between the optical patterns And the luminance can be improved. For example, referring to FIG. 1, when the longitudinal direction of the first optical pattern 112 is an x-axis and the longitudinal direction of the second optical pattern 122 is a y-axis, the x-axis and the y-axis are orthogonal to each other.

The height H of the second optical pattern 122 may be 10 占 퐉 to 30 占 퐉, specifically 10 占 퐉 to 25 占 퐉 and the apex angle? 2 may be 80 占 00 占 In this range, Can be. The pitch P2 of the second optical pattern 122 may be 10 占 퐉 to 50 占 퐉, specifically, 20 占 퐉 to 50 占 퐉, and the effect of increasing the brightness while preventing moire in the above range may be obtained.

The second optical pattern 122 may be formed of the same or different composition as the composition forming the first optical pattern 112, or may be formed of the same or different materials among the materials for the second base film.

The adhesive layer 130 is formed between one surface of the second optical sheet 120 and the first optical sheet 110 and the second optical sheet 120 to form the first optical sheet 110 and the second optical sheet 120 They can be bonded together and integrated. As used herein, "integral" means a state in which the first optical sheet and the second optical sheet are not separated from each other by a physical force.

The adhesive layer 130 may be formed of a composition including an adhesive resin that is excellent in transparency and capable of forming crosslinking. For example, the adhesive resin may be an epoxy resin, an epoxy resin-Lewis acid type, a polyethylol type, an unsaturated polyester-styrene type, an acrylic acid or a methacrylic acid ester type, It is preferable to use a methacrylic ester-based resin. Such resin types include oligomers such as polyurethane acrylate or polyurethane methacrylate, epoxy acrylate or epoxy methacrylate, polyester acrylate or polyester methacrylate, acrylates having polyfunctional or monofunctional groups Or methacrylate monomers, alone or in combination.

The thickness of the adhesive layer 130 may be 1 占 퐉 to 20 占 퐉, specifically 1 占 퐉 to 15 占 퐉, more specifically 1 占 퐉 to 5 占 퐉. In the above range, a sufficient adhesive force can be secured. Although the adhesive layer is formed on the entire lower surface of the second base film in Fig. 1, if the first optical pattern is penetrated to secure the adhesive force between the first optical sheet and the second optical sheet, It may be formed only in a part of the surface or may be formed in a specific pattern.

Hereinafter, a method of manufacturing a composite optical sheet according to an embodiment of the present invention will be described with reference to FIG. 4 is a cross-sectional view of a mold used in the production of a composite optical sheet according to an embodiment of the present invention.

A method of manufacturing a composite optical sheet according to an embodiment of the present invention includes the steps of fabricating a second optical sheet having a second optical pattern formed on one surface thereof by using a mold having a depression for a second optical pattern having an intrinsic height H, And a step of integrating the first optical sheet with the second optical sheet by using the adhesive layer, wherein the depressions for forming fine protrusions on the surface of the depressed portion for the second optical pattern at the depressed portion of only 0.65H or less from the lowermost surface of the depressed portion It may be more formed.

First, a mold is formed.

Referring to FIG. 4, a mold 300 used in manufacturing a composite optical sheet according to an embodiment of the present invention includes a mold body 310, and a second optical pattern is formed on one side of the mold body 310 And a depressed portion 330 for depressions for forming fine protrusions is formed on the surface of the depressed portion 320 of the depressed second optical pattern. . The engraved engaging portion 330 of the engraved fine protrusion is formed only at 0.35H or less only at 0.65H or less from the hypothetical lowermost face 310a of the second optical pattern engaging portion 320, Can be mitigated.

The mold 300 is formed by forming a second optical pattern shingling portion 320 on one surface of the mold main body 310 and sanding the surface of the second optical pattern shingling portion 320 using a sanding bead . The "sanding process" means that the sanding bead is jetted at a predetermined pressure onto the surface of the engaging portion 320 of the engraved second optical pattern.

The diameter of the sanding bead may be 1 to 50 탆, specifically 10 to 45 탆, and the degree of sanding to the trough portion of the second optical pattern in the above range is increased, thereby preventing the Newton ring phenomenon improvement effect from being reduced . The pressure during the sanding process may be in the range of 110 KPa to 250 KPa, and may have a Newton ring reduction effect in this range.

The material for forming the mold is not particularly limited, but may be made of a metal, a silicone, or a polymer material. Although not shown in FIG. 4, the surface of the mold having the stamping portion may be coated with a metal or the like.

Next, a second optical sheet is produced.

The second optical sheet can be manufactured by coating the composition for forming the second optical pattern on one surface of the mold having the depression portion and curing the surface of the second base film in contact with each other. The curing may be performed by one or more of thermosetting, light curing. Photocuring may include irradiation with energy of 100 mJ / cm ² to 1000 mJ / cm ^{2 with} ultraviolet rays having a wavelength of 190 nm to 400 nm, and thermal curing may include treatment at 35 ° C to 80 ° C for 30 minutes to 10 hours .

Next, a first optical sheet is produced.

The first optical sheet can be manufactured by coating the composition for forming the first optical pattern on the mold having the depressed portion for the first optical pattern of the engraved portion and curing the composition in contact with the first base film. The curing may be carried out in the same or different manner as the curing for producing the second optical sheet described above.

Finally, a composite optical sheet is produced.

The composite optical sheet can be produced by coating the other surface of the second base film with the composition for the adhesive layer and then impregnating the first optical pattern into the coating film of the composition for the adhesive layer and curing. The curing may be carried out in the same or different manner as the curing for producing the second optical sheet described above.

As described above, although the embodiment in which the second optical sheet is formed first is described, the first optical sheet may be formed first, or the first optical sheet and the second optical sheet may be formed at the same time.

Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIG. 5 is a perspective view of a liquid crystal display device according to an embodiment of the present invention.

5, a liquid crystal display 400 according to an exemplary embodiment of the present invention includes a light source 410, a light guide plate 420 for guiding light emitted from the light source 410, a reflector 420 disposed under the light guide plate 420, A diffusion sheet 430 disposed on the top of the light guide plate 420 and a composite optical sheet 440 disposed on the top of the diffusion sheet 430. The composite optical sheet 440 includes the sheet 450, May comprise a composite optical sheet of embodiments.

A light source cover 410a may be disposed outside the light source 410 of the backlight unit.

The light source 410 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.

The light guide plate 420 guides the light generated by the light source 410 to the diffusion sheet 530, and may be omitted when a direct-type light source is adopted.

The reflective sheet 450 reflects light generated from the light source 410 and supplies the light to the diffusion sheet 430.

The diffusion sheet 430 diffuses and scatters the light incident through the light guide plate 420 and supplies the light to the composite optical sheet 440.

The composite optical sheet 440 functions to refract light incident through the diffusion sheet 430 and condense the light onto a plane of a liquid crystal display panel (not shown). The composite optical sheet 440 may be formed of various shapes such as a shape of a light collecting portion and an angle of an inclined surface of a light collecting portion according to various design goals such as high condensing efficiency, wide viewing angle, prevention of moire phenomenon, And combinations are possible.

Although not shown in FIG. 5, the liquid crystal display panel and the antireflection layer are sequentially stacked on the liquid crystal display device 400 to form a liquid crystal display device. Although not shown in FIG. 5, a protective sheet, a polarizing plate, and the like may be further formed on the composite optical sheet 440.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Preparation Example: Composition for forming an optical pattern

50% by weight of fluorene derivative unsaturated resin (BPF-022, concentrating property, refractive index: 1.601), 20% by weight of phenoxybenzyl acrylate (refractive index: 1.56), phenylphenoxy ethyl acrylate (refractive index: 1.54), 1% by weight of Irgacure 184 as an initiator, and 3% by weight of Irgacure TPO were blended to prepare a liquid optical pattern composition for forming a refractive index of 1.58.

Example 1

Assuming that the average height of the engraved prism pattern is H at a sanding pressure of 110 kPa with a sanding bead having a diameter of 22.5 占 퐉 in a metal mold having a truncated triangular prism pattern with a height of 12.5 占 퐉, a pitch of 25 占 퐉 and a vertex angle of 90 占The mold was sandwiched one time so as to form fine protrusions only up to a height of 0.2H.

The composition for optical pattern formation of the production example was applied to the prism pattern of the metal mold subjected to the sanding treatment, and one side of the PET film for second base film (thickness: 50 탆, manufactured by TAK) was contacted. A D-type bulb (Type-D bulb) was attached to a non-electromotive ultraviolet irradiation device (600 W / inch) and irradiated with energy of 250 mJ / cm ² to 500 mJ / cm ² with a wavelength of 190 nm to 400 nm, And a PET film on which a prism pattern was formed on one side was separated from the metal mold to prepare a second optical sheet.

A composition for forming an optical pattern of a production example was applied to a metal mold with a triangular prismatic prism pattern having a height of 12.5 占 퐉, a pitch of 25 占 퐉, and a vertex angle of 90 占, and the PET film for the first base film (thickness: 50 mu m, manufactured by TAK Co., Ltd.). A D-type bulb (Type-D bulb) was attached to a non-electromotive ultraviolet irradiation device (600 W / inch) and irradiated with energy of 250 mJ / cm ² to 500 mJ / cm ² with a wavelength of 190 nm to 400 nm, And a PET film on which a prism pattern was formed on one side was separated from the metal mold to produce a first optical sheet.

An adhesive A-2579 (TESK) was applied to the other surface of the second base film PET film using a micro gravure coater to form an adhesive layer having a thickness of 2 m, and the length of the prism pattern of the first optical sheet and the second optical sheet The vertices of the prism pattern of the first optical sheet were infiltrated into the adhesive layer and cured so that the directions were orthogonal to each other to produce a composite optical sheet having the specifications of Table 1 below.

Examples 2 to 6

A composite optical sheet having the specifications of Table 1 having the maximum height at which fine protrusions were formed was manufactured by the same method as in Example 1, except that the diameter of the sanding beads and the sanding pressure were changed as shown in Table 1 below.

Comparative Example 1

A composition for forming an optical pattern of the production example was applied to a prism pattern of a metal mold having a triangular prismatic pattern with a height of 12.5 占 퐉, a pitch of 25 占 퐉 and a vertex angle of 90 占 and a PET film for a second base film Mu m, manufactured by TAK Co., Ltd.). A D-type bulb (Type-D bulb) was attached to a non-electromotive ultraviolet irradiation device (600 W / inch) and irradiated with energy of 250 mJ / cm ² to 500 mJ / cm ² with a wavelength of 190 nm to 400 nm, And a PET film on which a prism pattern was formed on one side was separated from the metal mold to produce a second optical sheet. A first optical sheet was prepared in the same manner as in Example 1, and an adhesive A-2579 (TESK Co.) was applied to the other surface of the second base film PET film using a micro gravure coater to form an adhesive layer having a thickness of 2 탆 , A vertex of the prism pattern of the first optical sheet was infiltrated into the adhesive layer and cured so that the longitudinal directions of the prism patterns of the first optical sheet and the second optical sheet were orthogonal to each other to produce a composite optical sheet having the specifications of Table 2 . At this time, the depth of the prism pattern of the first optical sheet penetrating into the adhesive layer is 2 탆 which is the thickness of the adhesive layer.

Comparative Example 2

A composite optical sheet having a maximum height of 0.7H in which fine protrusions were formed was produced in the same manner as in Example 1, except that the diameter of the sanding beads and the sanding pressure were changed as shown in Table 2 below.

The following composite optical sheets of Examples and Comparative Examples were evaluated for the following properties (1) to (4) and shown in Tables 1 to 2 below.

(1) Haze, transmittance, diffuse transmittance, parallel transmittance: The composite optical sheet was measured using a NIPPOPN DENSOKU, 300A haze meter.

(2) Relative luminance (%): An optical sheet to be measured was formed in an edge type backlight unit for a 32-inch LCD using an LED light source. The luminance was measured using a measuring instrument EZcontrast (Eldim). Relative luminance was calculated with the luminance of Comparative Example 1 as the reference luminance (luminance measured at the time of using the composite optical sheet of Examples and Comparative Examples) / (luminance of Comparative Example 1) x 100.

(3) Newton ring phenomenon: The composite optical sheet was applied to a 10.1-inch backlight unit and turned on. Then, visual inspection was performed to visually evaluate the formation of Newton rings.

 (4) Seat sheet: The optical sheet prepared above was assembled on a 10.1 inch panel (model: Samsung Galaxy Tab 10.1 SHW-M380S). After maintaining the temperature at 60 ° C and 75% relative humidity for 96 hours, the temperature was lowered at room temperature 25 ° C, then left to stand for 4 hours, and after 4 hours, the sample was visually observed. In the present specification, the room temperature means 25 ± 3 ° C unless otherwise specified, and the humidity means about 40 ± 5%.

The more severe the phenomenon The contrast difference is remarkable, and the evaluation is as follows.

◎: Minimized development.

○: There is a slight phenomenon.

△: There is a phenomenon.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Of the sanding bead
Diameter (탆) 45 45 45 10 10 10 Pressure during sanding (KPa) 110 150 250 110 150 250 Including adhesive layer include include include include include include Maximum height at which fine protrusions are formed * 0.2H 0.23H 0.3H 0.15H 0.2H 0.28H Haze (%) 93.1 93.2 93.2 93.3 93.2 93.2 Permeability (%) 2.58 4.41 5.84 3.56 5.93 7.73 Diffusing Permeability (%) 2.3 4.1 5.46 3.3 5.21 6.94 Parallel transmission (%) 0.28 0.31 0.38 0.26 0.72 0.79 Relative luminance (%) 93 90 87 89 87 84 Newton Ring phenomenon Good Good Good Good Good Good Sheet 욺 ◎ ◎ ◎ ◎ ◎ ◎

Comparative Example 1 Comparative Example 2 Diameter (탆) of sanding bead - 45 Pressure during sanding (KPa) - 500 Including adhesive layer - include Microprojection formed
Highest height * - 0.7H Haze (%) 93.1 94.1 Permeability (%) 2.03 11.2 Diffusing Permeability (%) 1.89 9.45 Parallel transmission (%) 0.14 1.75 Relative luminance (%) 100 83 Newton Ring phenomenon Good Bad Sheet 욺 △ ◎

In Table 1 and Table 2, H is the average height of the second optical pattern.

As shown in Table 1, the composite optical sheet of the present invention relaxes the Newton ring phenomenon, has no sheet peeling, and has less luminance loss as compared with Comparative Example 1.

On the other hand, Comparative Example 2 in which fine protrusions were formed at a portion exceeding 0.65H as shown in Table 2 had a problem of occurrence of Newton rings.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

And an adhesive layer which is located between the first optical sheet and the second optical sheet and integrates the first optical sheet and the second optical sheet,
The second optical sheet includes a second optical pattern having an average height H and fine protrusions formed on a surface of the second optical pattern,
Wherein the fine protrusions are formed only on a surface of 0.65H or less from the lowermost surface of the second optical pattern. The composite optical sheet according to claim 1, wherein the H is 10 탆 to 30 탆. The composite optical sheet according to claim 1, wherein the second optical pattern includes a prism having a polygonal section. The composite optical sheet according to claim 1, wherein the first optical sheet comprises a prism having a polygonal section. The composite optical sheet according to claim 1, wherein the first optical sheet includes a prism having a polygonal section, the prism penetrates the adhesive layer, and the second optical pattern includes a prism having a polygonal section. The optical sheet according to claim 1, wherein the first optical sheet includes a prism having a polygonal section, the prism penetrating the adhesive layer,
Wherein the second optical sheet is formed on the first optical sheet and includes a second base film, the second optical pattern formed on the second base film, and the fine protrusions formed on the surface of the second optical pattern And the second optical pattern includes a prism having a polygonal section. Providing a first optical sheet,
Comprising integrating a second optical sheet having an optical pattern formed on one surface of a mold having a depressed portion for an optical pattern of an engraved pattern having an average height H, with the first optical sheet using an adhesive layer,
Wherein the surface of the optical element shingling portion is provided with depressions for forming fine protrusions only in the range of 0.65H or less from the lowermost surface. 8. The method of manufacturing a composite optical sheet according to claim 7, wherein the embossed portion for forming the fine protrusion of the engraved portion is formed by sanding the optical element shingles. 9. The method of manufacturing a composite optical sheet according to claim 8, wherein the sanding treatment comprises spraying a sanding bead having a diameter of 1 to 50 占 퐉 onto the surface of the optical element chucking portion at a pressure of 110 KPa to 250 KPa. An optical display device comprising the composite optical sheet according to any one of claims 1 to 6.

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