KR20120112289A - Optical sheet - Google Patents

Abstract

PURPOSE: An optical sheet is provided to increase production efficiency and to reduce manufacturing costs by reducing failure rate and to prevent brightness reduction due to damage. CONSTITUTION: An optical sheet comprises a base layer(10), a structure layer(20), and a resin hardening layer(30). The structure layer is formed on the base layer and structuralizes the surface. The resin hardening layer is formed on the structure layer and contains an element having slip property in a molecular chain.

Description

Optical sheet

The present invention relates to an elastic optical sheet used in a liquid crystal display (hereinafter referred to as LCD).

LCD, which is used as an optical display element, is an indirect light emission method that displays an image by controlling transmittance of an external light source, and a backlight unit, which is a light source device, is used as an important component for determining the characteristics of the LCD.

In particular, with the development of LCD panel manufacturing technology, there has been a demand for a thin and bright LCD display. Accordingly, various attempts have been made to increase the brightness of a backlight unit. For example, a monitor, a PDA Is a measure of its superiority in that a liquid crystal display used as a light source emits bright light from a small energy source. Therefore, in the case of LCD, the front brightness is very important.

LCD has a structure in which light passing through the light diffusion layer is diffused in all directions, so the light emitted to the front becomes very insufficient, and thus, efforts to display higher luminance with less power consumption continue. In addition, efforts are being made to widen the viewing angle so that a larger display can be viewed by more users.

For this purpose, increasing the power of the backlight increases power consumption and heat loss. As a result, the battery capacity and the battery life of the portable display are reduced.

Accordingly, a method of directing light to increase brightness has been proposed, and various lens sheets have been developed for this purpose. The representative sheet has a prism array, that is, a structure in which several peaks and valleys are arranged side by side in a straight line.

Here, the prism structure has a triangular array structure having an inclined surface for improving luminance in the front direction. Therefore, the upper part of the prism structure is in the shape of a mountain, and the upper part of the mountain is easily broken or worn by small external scratches, thereby causing a problem in that the prism structure is damaged. Since the angles emitted from the same type of prism structure are the same for each array, the luminance is reduced due to the difference in the light paths emitted between the damaged parts and the normal parts even by a small crush on the corners of the triangle or minute scratches on the inclined surface. It is lowered and a defect occurs. Therefore, even in the case of the production of the prism sheet, even in the case of minute defects, the front surface of the produced prism sheet may not be used depending on the position. This leads to a decrease in productivity, which in turn is a burden of cost increase. In fact, even in the assembling of the backlight module, defects due to damage to the prism structure due to scratches when handling the prism sheet become a significant problem.

In addition, optical sheets in the form of structures are applied in consideration of brightness enhancement, concealment, and viewing angle, and when they are mounted on a backlight unit, lamination is performed with other sheets and films. As the upper and lower prism film contacted with each other, there was a risk of easily damaging the structure. In addition, care has to be taken in handling or transporting these optical sheets.

Therefore, in order to prevent damage of such a structure, the conventional protective film was laminated in some cases. However, since LCD panels are becoming thinner, there is a tendency to omit the film or to use a sheet having a composite function, and also to increase production cost, time, and physical efficiency due to the addition of a process of laminating a protective film.

Accordingly, the present invention is to provide an optical sheet that is easy to handle by preventing damage by imparting slip properties.

In addition, the present invention is to provide an optical sheet that is easy to handle by preventing damage to the structure.

In another aspect, the present invention is to provide an optical sheet that is excellent in workability and reliability to reduce the production rate and reduce the production cost and increase the production efficiency.

On the other hand, the present invention is to provide an optical sheet that does not require a protective film.

Accordingly, the present invention provides an optical sheet including a cured resin layer containing an element having slip property in a molecular chain as a first preferred embodiment.

The present invention is a second preferred embodiment, the base layer; And a structural layer formed on the substrate layer and having a structured surface, wherein the structural layer is a cured resin layer containing an element having slip property in a molecular chain.

The present invention is a third preferred embodiment, the base layer; A structural layer formed on the substrate layer and having a structured surface; And a cured resin layer formed on the structural layer and containing an element having a slip property in molecular chains.

In the above embodiment, it may further include a resin cured layer containing an element having a slip property in the molecular chain on the other surface where the structural layer of the base layer is not formed.

In the above embodiment, the structured structure layer may be a cured resin layer containing an element having a slip property in the molecular chain.

In the above embodiment, the element having slip property may be F or Si.

In the above embodiment, the resin cured layer may be formed from a curable resin containing F or Si.

In the above embodiment, the curable resin may include any one or more selected from an organosilicon compound or a fluorine acrylate.

In the above embodiment, the structural layer may be polygonal in profile, streamlined polygon, semicircle, semi-elliptic polyhedron, or may be polygonal in shape, polygonal in peak, semicircular, semi-elliptic columnar shape. One or more patterns selected from among polygonal cross-sections, polygonal peaks, semi-circular and semi-elliptic curved column shapes may be formed.

As described above, the present invention therefore provides an optical sheet that is easy to handle by preventing slipping by imparting slip properties.

In addition, the present invention is to provide an optical sheet that is easy to handle by preventing damage to the structure.

In another aspect, the present invention is to provide an optical sheet that is excellent in workability and reliability to reduce the production rate and reduce the production cost and increase the production efficiency.

On the other hand, the present invention is to provide an optical sheet that does not require a protective film.

1 is a cross-sectional view of an optical sheet according to a preferred embodiment of the present invention;
2 is a cross-sectional view of an optical sheet according to another preferred embodiment of the present invention;
3 is a cross-sectional view of an optical sheet according to another preferred embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

The optical sheet of the present invention provides an optical sheet including a resin cured layer containing an element having slip property in a molecular chain.

The optical sheet of the present invention is not particularly limited, but includes a base layer and a structural layer formed on one or both surfaces thereof, and the structural layer may include a plurality of three-dimensional structures as a cured resin layer having a structured surface. . Alternatively, the optical sheet including the structural layer may be integrally formed by extrusion.

Here, the optical sheet of the present invention may be provided with a resin cured layer containing an element having slip property in the molecular chain on such a structure layer, or curable resin containing an element having slip property in the composition for forming the structure layer. It may be to include. Moreover, the resin cured layer containing the element which has slip property in molecular chain may be further provided on the base material layer which does not form a structural layer.

As described above, the optical sheet of the present invention has an element having slip property in the molecular chain, thereby providing uniform and continuous slip property than simply adding slip material to the composition for forming a structural layer or coating the surface. have.

Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings.

1 is a cross-sectional view of an optical sheet according to a preferred embodiment of the present invention, and includes an optical sheet including a structural layer 20 which is a cured resin layer containing an element having slip property in molecular chains on one surface of a base layer 10. An example is shown.

FIG. 2 is a cross-sectional view of an optical sheet according to another preferred embodiment of the present invention, and includes a cured resin layer 30 containing an element having slip property in molecular chains on a structural layer 20 formed on a base layer 10. It shows an example of an optical sheet comprising a.

3 is a cross-sectional view of an optical sheet according to another preferred embodiment of the present invention, in which the element having slip property in molecular chains is formed on the surface of the optical sheet of FIG. An example of the optical sheet which further formed the resin hardened layer 30 containing is shown.

In the drawings, the same reference numerals are used for the same components for convenience, but this does not mean that the compositions and shapes are the same.

When the optical sheet of the present invention is separately provided with a resin cured layer 30 containing an element having slip property in molecular chains on the structural layer 20 (FIGS. 2 and 3), the curable resin and photoinitiator are included. The composition can be formed by coating on the structural layer (20). In this case, the curable resin included in the resin cured layer 30 may be at least one selected from an organosilicon compound or a fluorine acrylate including a silicon acrylate and a siloxane resin, and a photoinitiator may be used without particular limitation. For example, BAPO series or MAPO series can be used. In this case, the composition may be coated on the structural layer 20 to form the resin cured layer 30, and when the composition providing the slip property is separately coated on the structural layer, the front coating may be evenly coated. The coating method of can be used. Therefore, the thickness can be very thin, less than 1 μm, and even if the thickness of the cured resin layer 30 is thin, it is not a problem in providing a desired slip property. Thereby, the cured resin is cured and the resin cured layer 30 in which the Si or F element which contains slip property exists in a molecular chain is formed.

In this case, the structural layer 20 is formed by a conventionally known method, and the structural layer 20 may be formed by applying a composition containing a curable binder resin and a photoinitiator to a base layer and then curing the form by forming a structure with a mold. have. The binder resin can be used without limitation as long as it is a resin known as a composition for forming a prism. Examples thereof include urethane acrylate, bromine acrylate, epoxy acrylate, fluorene acrylate, and the like.

In this case, the pitch of the three-dimensional structure of the structural layer 20 is not particularly limited, but is preferably 25 μm to 500 μm, and the height of the three-dimensional structure constituting the structural layer 20 is not particularly limited, but is 12 μm. It is preferable that it is -300 micrometers. This is to minimize light loss in consideration of refraction of light and to efficiently collect light.

The shape of the three-dimensional structure constituting the structural layer 20 is preferably a structure that is symmetrical with respect to the center line in the vertical direction passing through the peak point, but is not limited thereto.

The resin cured layers 30 and 40 may not only be formed on the structural layer 20 as shown in FIG. 3, but are further formed on the base layer 10 on which the structural layer 20 is not formed to provide slip property. By doing so, damage to the base layer can be prevented during handling of the lamination of the optical sheet.

As described above, the optical sheet of the present invention may be formed separately from the cured resin layers 30 and 40, but may include a curable resin containing an element having slip property in the structural layer-forming composition.

In this case, a composition comprising a plurality of structures by a known method is coated on the base layer 10 by coating a composition comprising a binder resin for forming the structural layer 20, a curable resin providing slip properties, and a photoinitiator. ) Can be formed. The binder resin may be used without limitation as long as it is a resin known as a composition for forming a prism. Materials such as vinyl cyanide compounds such as ronitril can be used. Among them, it is particularly preferable to use an unsaturated fatty acid ester resin because the optical properties such as transparency should be high. In this case, the content of the curable resin that provides slip is not particularly limited, but is preferably 0.01 to 5.0 parts by weight based on 100 parts by weight of the binder resin.

As a result, the binder resin and the curable resin of the structural layer 20 itself may be cured to form the structural layer 20 in which the Si or F element containing slip is present in the molecular chain.

As described above, the optical sheet of the present invention may include an element having slip property inside or outside the structural layer 20, thereby preventing an increase in a defective rate due to a decrease in workability or reliability when applied to the backlight unit.

The optical sheet of the present invention comprises a structural layer 20 having a plurality of three-dimensional structures as a resin cured layer structured surface, the structural layer 20 is a polygon, semicircular, semi-elliptical, longitudinal cross-section, polygonal It may be a polyhedron shape, or may be a polygonal shape, a polygon with a peak streamline, a semicircle, a semi-elliptic columnar shape, or a curved columnar shape with a polygonal profile, a streamlined polygonal peak, a semicircle, or a semi-ellipse profile. . It may also be a shape in which one or more of these patterns are mixed.

It also includes a case having a structure arranged in at least one concentric shape when viewed in plan view, and has a structure in which mountains and valleys are formed along the concentric circles.

When the longitudinal cross section of the structural layer 20 is polygonal, the characteristics of the luminance and the wide viewing angle vary greatly depending on the angle of the peak portion. It may be advantageous, and it may be more advantageous that it is 85-95 °.

Alternatively, when the longitudinal section of the structural layer 20 is polygonal, the peak portion may be rounded so that the peak is streamlined. In this case, the longest width of the streamlined portion in the longitudinal cross-section of the structural layer 20 may be 0.5 to 10 μm. have.

The base layer 10 of the optical sheet is any one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polymethacrylate, polymethyl methacrylate, polyacrylate, polyimide, polyamide It may be formed of one or more materials, and may further include light diffusing particles to form a structure in which the irregularities are formed. The base layer 10 may have a thickness of 10 to 1000 μm in terms of mechanical strength, thermal stability, and flexibility, and to prevent loss of transmitted light, and more preferably 15 to 400 μm.

Although the optical sheet separating the base layer 10 and the structural layer 20 has been described above, the present invention provides the resin described above on one or both surfaces of the optical sheet extruded with one type of resin without distinguishing the base layer and the structural layer. You may form a hardened layer.

In the description of the present invention with reference to the accompanying drawings, but described mainly with an optical sheet having a specific shape and structure, the present invention can be variously modified and changed by those skilled in the art, such variations and modifications belong to the protection scope of the present invention Should be interpreted as

Hereinafter, the embodiments of the present invention will be described in more detail, but the scope of the present invention is not limited to these examples.

Example 1

50 parts by weight of 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene, 32 parts by weight of phenoxyethyl acrylate and tris (2-hydroxyethyl) relative to 100 parts by weight of the total composition. 10 parts by weight of isocyanurate triacrylate, 2 parts by weight of 1,6 hexadiol diacrylate, 2.5 parts by weight of 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2 (2'hydroxy-5-t 2 parts by weight of -octoxybenzotriazole, 1 part by weight of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 0.5 part by weight of silicone acrylate were added and heated to 40 ° C. for about 1 hour to completely dissolve it. The composition was then applied onto one surface of polyethylene terephthalate (KOLON, 188 μm), which is a substrate layer, and placed on a frame of a prism roller at 35 ° C. in a UV-irradiating apparatus (Fusion, 600 Watt / inch ² ). equipped with a D bulb irradiated with 900mJ / cm ² in the direction of the substrate layer to the prism apex angle is 90 °, a pitch of 50㎛, height 27㎛ To form a triangular prism-shaped An optical sheet was manufactured.

Example 2

In Example 1, 50.495 parts by weight of 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene and 0.005 part by weight of silicon acrylate were added to prepare an optical sheet.

Example 3

In Example 1, 45 parts by weight of 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene and 5.5 parts by weight of silicone acrylate were added to prepare an optical sheet.

Example 4

In Example 1, a lenticular lens having a semicircular longitudinal section, a pitch of 50 μm, and a height of 27 μm was formed to manufacture an optical sheet.

Example 5

In Example 1, the optical sheet was manufactured by forming a linear prism having a peak portion of a streamlined prism, a pitch of 50 μm (the longest width of the streamlined portion of the prism longitudinal section is 3 μm), and a height of 27 μm.

Example 6

In Example 1, the optical sheet was manufactured by forming a linear prism having a pentagonal longitudinal section, a vertex angle of 95 °, a pitch of 50 µm, and a height of 27 µm.

Example 7

In Example 1, an optical sheet was manufactured by forming a curved prism having a semicircular longitudinal section, a pitch of 50 μm, and a height of 27 μm.

Example 8

In Example 1, a dot-shaped optical sheet having a hemispherical longitudinal section, a pitch of 60 μm, and a height of 30 μm was manufactured.

Example 9

Except for the silicone acrylate in Example 1, to prepare an optical sheet with 50.5 parts by weight of 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene silicone acrylate by spray method After the coating on the front of the optical sheet was prepared by irradiating 300mJ / cm ² in the structure layer direction by mounting the type-D bulb to the ultraviolet irradiation device (Fusion, 600Watt / inch ² ).

Example 10

Except for the silicone acrylate in Example 1, to prepare an optical sheet with 50.5 parts by weight of 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene silicone acrylate by spray method Was applied to the front surface of the optical sheet and the substrate layer and then mounted to the ultraviolet irradiation device (Fusion, 600Watt / inch ² ) type-D bulb was prepared by irradiating 900mJ / cm ² in the direction of the substrate layer.

Comparative Example 1

An optical sheet was manufactured in the same manner as in Example 1, except that silicone acrylate was not used.

Comparative Example 2

An optical sheet was manufactured in the same manner as in Example 4, except that silicone acrylate was not used.

Comparative Example 3

An optical sheet was manufactured in the same manner as in Example 5, except that silicone acrylate was not used.

Comparative Example 4

An optical sheet was manufactured in the same manner as in Example 8, except that silicone acrylate was not used.

In each of the above Examples and Comparative Examples, scratch resistance, frictional force and luminance were measured as follows.

(1) scratch resistance

When a minimum pressure was applied to the optical sheets of the Examples and Comparative Examples using the basic weight of the Big Heart test apparatus of IMOTO, the scratches of the structural layer were measured, and the results are shown in Table 1 below. The degree of damage was visually judged and the criteria are as follows.

Bad scratch resistance ← × <△ <○ <◎ → Excellent scratch resistance

(2) frictional force

The optical sheets of the Examples and Comparative Examples were measured using a SLED having a standard weight of 200 g by a friction test apparatus of Toyoseiki, and the results are shown in Table 1 below.

(3) luminance

The optical sheets of Examples and Comparative Examples were mounted on a 17-inch backlight unit for liquid crystal display, and the luminance was measured and averaged by measuring a designated 13-point luminance using a BCON-7 BM-7 luminance meter. The results are shown in the following table. Same as 1.

division Scratch resistance Friction Luminance Example 1 ○ 5.0N 2456 Example 2 △ 6.5N 2450 Example 3 ◎ 4.0N 2395 Example 4 ◎ 6.5N 2247 Example 5 ○ 6.0N 2419 Example 6 ○ 5.0N 2444 Example 7 ○ 5.0N 2429 Example 8 ◎ 6.0N 2237 Example 9 ○ 5.0N 2450 Example 10 ○ 5.0N 2451 Comparative Example 1 × 7.0N 2455 Comparative Example 2 △ 7.5N 2239 Comparative Example 3 × 7.0N 2419 Comparative Example 4 △ 7.0N 2281

As shown in Table 1, the optical sheet according to the embodiment of the present invention can be seen that the scratch resistance of the structural layer is very excellent. In addition to the change in luminance and friction due to the difference in the shape of the structural layer, the lower the content of the silicone acrylate to impart slip resistance, the lower the scratch resistance, and the higher the content of the silicone acrylate, the lower the luminance. have.

As a result, the optical sheet of the present invention lowers the frictional force of the external impact by including a curable resin that imparts slippage properties that do not cause a decrease in luminance without damaging the structure during external impact, thereby flexibly coping with the external impact and not easily damaged. Can be.

10: substrate layer 20: structure layer
30, 40: resin cured layer

Claims (8)

An optical sheet comprising a resin cured layer containing an element having slip property in a molecular chain. A base layer;
A structural layer formed on the substrate layer and having a structured surface; And
It is formed on the said structural layer, The optical sheet containing the resin cured layer containing the element which has a slip property in a molecular chain. The method of claim 2,
The optical sheet which further contains the resin cured layer containing the element which has a slip property in a molecular chain on the other surface in which the structural layer of a base material layer is not formed. The method of claim 2,
The structural layer whose surface is structured is an optical resin cured layer containing an element having slip property in a molecular chain. The method according to any one of claims 1 to 4,
An optical sheet, wherein the element having slip property is F or Si. The method according to any one of claims 1 to 4,
The resin cured layer is formed from a curable resin containing F or Si. The method according to claim 6,
Curable resin is an optical sheet, characterized in that it comprises at least one selected from organosilicon compounds or fluorine-based acrylate. The method of claim 2,
The structural layer may be polygonal in profile, streamlined polygonal, semicircular, semi-elliptic polyhedron, or longitudinal cross-section polygonal, peaked streamlined polygon, semicircle, semi-elliptic columnar shape, or longitudinal cross-section The optical sheet, characterized in that a plurality of one or more patterns selected from a curved columnar shape of a polygonal, semi-circular, semi-elliptic peaks are streamlined.

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