KR20080112868A - Optical sheet with increased adhesive force and filter comprising the same, and display device having the sheet or the filter - Google Patents

Abstract

An optical sheet improving adhesive force without degradation of image quality, filter including the same, and display device including the same or filter are provided to reduce mesophase by improving contrast ratio. An optical sheet(200) improving adhesive force without degradation of image quality comprises an optical transmission part(210) and a plurality of outdoor light absorption parts(220). The optical transmission part has a plurality of grooves which are arranged separately. The outdoor light absorption part is filled in the groove, and is made of a light absorption material. A surface of the outdoor light absorption part and a surface of the optical transmission part include each surface illuminance(SR220, SR210). A surface illuminance included on the surface of the outdoor light absorption part is larger than a surface illuminance included on the surface of the optical transmission part.

Description

Optical sheet with increased adhesive force and filter comprising the same, and display device having the sheet or the filter}

1 is an exploded perspective view showing a schematic configuration of an image display device equipped with a filter including an optical sheet according to an embodiment of the present invention.

2A is an exploded cross-sectional view of a filter having an optical sheet according to an embodiment of the present invention, and FIG. 2B is an exploded cross-sectional view of a filter having an optical sheet according to another embodiment of the present invention.

3 is a cross-sectional view of an optical sheet according to an embodiment of the present invention.

4 is an enlarged view illustrating a portion A of FIG. 3.

FIG. 5 is a partially separated perspective view illustrating a modified example of the optical sheet of FIG. 3 to prevent moiré phenomenon. FIG.

<Explanation of symbols for main parts of the drawings>

1: image display device 10: case

20: drive circuit board 30: panel assembly

40: filter 50: cover

100: color correction film 200: optical sheet

210: light transmission unit 220: external light absorption unit

230: base film 240: protective film

300: electromagnetic wave shielding film 400: hard coating layer

500: antireflection film FB: filter base

SR ₂₁₀ , SR ₂₂₀ : Surface Roughness

The present invention relates to an optical sheet having an improved adhesion, a filter having the same, and an image display device having the optical sheet or the filter, and more particularly, to improve the adhesion of the optical sheet and to reduce the double phase formation and contrast ratio resulting from layer separation. An optical sheet having no deterioration in image quality, such as a filter, a filter including the same, and an image display device including the optical sheet or the filter.

Recently, many kinds of image display devices have been developed and put into practical use. Such image display devices are, for example, liquid crystal image display devices (LCDs), plasma display panels (PDPs), electroluminescent displays (FEDs), and cathode ray tube image display devices. (CRT), fluorescent display tubes, field emission display panels. Such image display devices display color images by implementing three primary colors of red, blue, and green in principle.

Such an image display device includes a panel assembly that forms an image, and a filter that shields electromagnetic waves, near infrared rays, and / or orange light emitted from the panel assembly, and has functions such as surface reflection prevention, color correction, and / or resolution enhancement. Equipped. Since these filters are mounted on the front of the panel assembly, the light transmission must also be satisfied at the same time.

In addition, in the image display apparatus, in an external bright condition, that is, a bright room condition, external ambient light may pass through a filter into the panel assembly. In this case, overlap of incident light emitted in the panel assembly and external environmental light introduced through the filter from the outside occurs. For this reason, there is a problem that the contrast ratio is lowered in the bright room condition and the screen display capability of the image display device is poor. Japanese Laid-Open Patent Publication No. 2005-338270 discloses a viewing angle control sheet for solving this problem. That is, the viewing angle control sheet has a structure in which an external light absorbing layer including a wedge-shaped black light absorbing material is arranged at a predetermined interval in a transparent light transmitting portion, and a material having a lower refractive index and a light absorbing material than the light transmitting portion is filled in the external light absorbing layer. Therefore, techniques for increasing the transmittance of the image light source incident in the oblique direction to the external light absorbing layer to the observer side more effectively by using the total reflection principle have been developed. However, the optical sheet to which such a technique is applied is likely to cause delamination due to the weakening of adhesion when attached to other components in the filter and the adhesive layer. The problem of reducing image quality is caused by causing double image formation and the like.

In order to solve the problems of the conventional image display apparatus as described above, an object of the present invention is to improve the adhesion to the optical sheet.

It is another object of the present invention to provide an optical sheet which improves contrast ratio and reduces double phase.

Another object of the present invention is to provide an optical sheet that can prevent the moiré phenomenon.

Still another object of the present invention is to provide a filter including the optical sheet.

Still another object of the present invention is to provide an image display apparatus having the optical sheet or the filter, which can realize clear image quality, improve resolution, and prevent moiré phenomenon.

In order to solve the problems of the conventional image display apparatus as described above

The present invention,

A light transmitting portion having a plurality of groove portions disposed to be spaced apart from each other; And

And a plurality of external light absorbing parts filled in the groove part and including a light absorbing material.

Comprises a surface roughness (SR ₂₂₀₎ and the surface roughness (SR ₂₁₀₎ having a surface, each of the external light absorbing portion surface and the light transmitting portion corresponding to this, the surface roughness (SR ₂₂₀₎ provided on a surface of the external light absorbing portion The optical sheet larger than the surface roughness (SR ₂₁₀ ) provided on the surface of the light transmitting portion corresponding thereto.

According to the exemplary embodiment of the present invention, the surface roughness SR ₂₂₀ of the external light absorbing part is 0.15 to 5.0 μm, and the surface roughness SR ₂₁₀ of the light transmitting part is 0.05 to 0.5 μm.

According to another embodiment of the invention,

The surface roughness SR ₂₂₀ and the surface roughness SR ₂₁₀ corresponding to the external light absorbing part satisfy the following conditions:

0.1 ≦ SR ₂₂₀ −SR ₂₁₀ ≦ 0.45 μm.

According to another embodiment of the present invention, the shape of one end surface of the external light absorbing portion is triangular, square or trapezoidal.

According to another embodiment of the present invention, the external light absorbing portion is arranged in a stripe shape, a matrix shape, or a wave shape.

According to another embodiment of the invention, the optical sheet is a high resolution sheet.

According to another embodiment of the present invention, the longitudinal direction of the external light absorbing portion and one side of the optical sheet are not parallel to each other and have a bias angle α greater than 0 °. Here, the "length direction" is defined as the longitudinal direction when the external light absorbing portion is a straight stripe, and when the external light absorbing portion is a matrix type, it is defined as the linear direction connecting the corresponding portions of each matrix component. In the case where the absorbent portion is wavy, it is defined as a straight line connecting the corresponding portions of each wave period to each other.

In addition, the present invention,

Provided is a filter for an image display device including an optical sheet and a filter base according to any one of the above embodiments.

According to an embodiment of the present invention, the filter base includes an antireflection film, a hard coating layer, an electromagnetic wave shielding film, or a combination thereof.

According to another embodiment of the present invention, the image display device filter further comprises a color correction film on the image light source side surface of the optical sheet.

In addition, the present invention,

An image display device including a filter for an optical sheet or an image display device according to any one of the above embodiments is provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view showing a schematic configuration of an image display apparatus equipped with a filter including an optical sheet according to an embodiment of the present invention, and FIG. 2A is a filter including an optical sheet according to an embodiment of the present invention. 2B is an exploded cross-sectional view of a filter having an optical sheet according to another embodiment of the present invention.

Referring to FIG. 1, an image display device 1 equipped with a filter including an optical sheet according to an embodiment of the present invention includes a case 10, a cover 50 covering an upper portion of the case 10, and the A driving circuit board 20 accommodated in the case 10, a panel assembly 30 for forming an image, and a filter 40 are included.

The visible image formed in the panel assembly 30 by the electrical signal applied from the driving circuit board 20 is emitted to the outside through the filter 40.

2A and 2B, the filter 40 includes a filter base FB including a color correction film 100, an optical sheet 200, and an antireflection film 500. do.

The color correction film 100 typically includes, for example, a neon light blocking dye, but may also include a near infrared absorbing compound or a dye.

Examples of neon light blocking pigments included in the color correction film 100 include cyanine-based, squarylium-based, azomethine-based, xanthene-based, oxonol-based, or azo-based compounds. And the like can be used. Neon light refers to unnecessary light around the wavelength of about 585 nm generated by the excitation of neon gas.

When the color correction film 100 includes a near infrared absorbing compound, such a compound includes a resin containing a copper atom, a resin containing a copper compound or a phosphorus compound, a copper compound or a thio element derivative. Resin, or a resin containing a tungsten-based compound may be used. Near-infrared rays cause malfunctions of peripheral electronic devices, and thus their shielding is necessary.

The optical sheet 200 includes a light transmitting unit 210 and an external light absorbing unit 220 formed on the base film 230, and is disposed below the color correction film 100. The optical sheet 200 having such a configuration includes, for example, a high resolution sheet, but the present invention is not limited thereto. Here, the high resolution sheet is a broad concept which collectively refers to the sheet used for the purpose of raising the resolution of an image display apparatus.

The light transmitting portion 210 is a portion that transmits the light emitted from the panel assembly 30 of FIG. 1. The light transmitting part 210 may be formed of a curable resin. Specifically, as the light transmitting portion 210 may be used an acrylate resin or the like cured by ionizing radiation or thermal energy.

In addition, it is preferable that the light transmitting portion 210 is transparent, which means not only completely transparent but also an extent that can be recognized as transparent in the art. The light transmitting part 210 generally has a shape complementary to the shape of the external light absorbing part 220 to be described later, but the present invention is not limited thereto. That is, the light transmitting portion 210 is formed with a groove portion g ₂₁₀ spaced apart from each other at predetermined intervals, and the groove portion g ₂₁₀ is filled with a light absorbing material to form an external light absorbing portion 220 which will be described later. do. In the present embodiment, the groove g ₂₁₀ is illustrated as being formed at the image light source side end of the light transmitting part 210, but the present invention is not limited thereto, and the groove g ₂₁₀ is the light transmitting part 210. It may be formed at the observer side end of. It is preferable that the refractive index n ₂₁₀ of the light transmitting part 210 is 1.33 to 1.6. When the refractive index n ₂₁₀ is less than 1.33, it is not preferable because it is actually difficult to manufacture, and when the refractive index n ₂₁₀ is exceeded, the transmittance of the light transmitting unit 210 is significantly decreased, and the contrast ratio is also reduced, which is not preferable because the overall resolution is reduced.

In addition, one surface of the light transmitting portion 210, that is, the surface of the image light source side is not completely smooth but has a predetermined roughness, that is, surface roughness SR ₂₁₀ of 0.05 to 0.5 mu m. If the surface roughness SR ₂₁₀ is less than 0.05 µm, it is not preferable to actually manufacture it. If the surface roughness SR ₂₁₀ is greater than 0.5 µm, the surface roughness SR ₂₁₀ is not preferable because the transmitted light of the image light source is diffusely reflected to form a ghost.

The external light absorbing part 220 fills the light absorbing material in the groove g ₂₁₀ between the light transmitting parts 210 disposed to be spaced apart from each other at predetermined intervals, and absorbs the external ambient light, thereby improving the contrast ratio in the bright room condition. This is to maintain high resolution. 2A illustrates a case in which one end face of the external light absorbing unit 220 has a quadrangle shape, and FIG. 2B illustrates a case in which one end face of the external light absorbing unit 220 has a trapezoidal shape. Meanwhile, the present invention is not limited to those illustrated in FIGS. 2A and 2B or FIGS. 3 to 5 to be described below, and the light transmitting part 210 is formed in a flat plate shape without grooves and absorbs external light. 220 may be disposed on one surface of the light transmitting unit 210, that is, the surface of the color correction film 100. The external light absorbing part 220 may be formed of a material capable of absorbing light, for example, a black inorganic material, a black organic material, and / or a blackened metal. In the case of the blackened metal, since the electrical resistance is low, when the external light absorbing part 220 is formed therefrom, the external light absorbing part 220 may control the electromagnetic resistance by adjusting the content of the metal powder or the thickness of the metal thin film. It may also perform a shielding function. Typically, the external light absorbing part 220 may be formed of an ultraviolet curable resin containing carbon. The refractive index n ₂₂₀ of the external light absorbing part 220 is preferably in the range of 1.33 to 1.6 similarly to the light transmitting part 210.

In addition, one surface of the external light absorbing unit 220, that is, the surface of the image light source side has a predetermined roughness, that is, surface roughness SR ₂₂₀ of 0.15 to 5.0 μm. When the surface roughness SR ₂₂₀ is less than 0.15 μm, the adhesive strength is weak, which is not preferable. When the surface roughness SR ₂₂₀ is larger than 5.0 μm, the light transmittance of the image light source is low, which is not preferable. More preferably, the surface roughness SR ₂₂₀ of the external light absorbing part 220 is greater than the surface roughness SR ₂₁₀ of the light transmitting part 210, and most preferably the surface roughness SR ₂₂₀ of the external light absorbing part _220. ) And the surface roughness SR ₂₁₀ of the light transmitting portion 210 satisfy the following conditions:

0.1 ≦ SR ₂₂₀ −SR ₂₁₀ ≦ 0.45 μm.

Thus, by adjusting the surface roughness (SR ₂₁₀ , SR ₂₂₀ ) of the image light source side of each of the light transmitting unit 210 and the external light absorbing unit 220, the optical sheet with improved adhesion without reducing the light transmittance and the external light absorption of the image light source 200 can be obtained. That is, the image light source side surface roughness SR _{210 of the} light transmitting part 210 is lowered to reduce the diffuse reflection ratio of the light transmitting part 210, and the image light source side surface roughness SR ₂₂₀ of the external light absorbing part ₂₂₀ is increased. The surface adhesion of the external light absorbing unit 220 may be increased. At this time, there is no change in the external light absorption rate of the external light absorption unit 220. In general, the greater the surface roughness of an object, the greater the surface adhesion of that object. Here, the adhesive force of the optical sheet 200 refers to the adhesive force between the external light absorbing unit 220 and the color correction film 100 or a film having a different function in the filter. As such, by improving the adhesion of the optical sheet 200, problems such as separation of layers caused by the weakening of adhesion and resulting filter contamination and deterioration of image may be improved.

The base film 230 is disposed on one surface of the light transmitting part 210, that is, the surface opposite to the external light absorbing part 220. The base film 230 serves to support the light transmission unit 210 in which the external light absorbing unit 220 is formed. Specifically, the base film 230 is polyethersulphone (PES), polyacrylate (PAR, polyacrylate), polyether imide (PEI, polyetherimide), polyethylene naphthalate (PEN, polyethyelene naphthalate), polyethylene terephthalate (PET, polyethyleneterephthalate), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose tri acetate (TAC), cellulose acetate propionate (cellulose acetate propionate (CAP)) may be formed of one or more substances selected from the group consisting of: Preferably, it may be polycarbonate (PC), polyethylene terephthalate (PET, polyethyeleneterephthalate), cellulose tri acetate (TAC), or polyethylene naphthalate (PEN, polyethyelene naphthalate). In addition, the base film 230 is preferably formed of a material having the same or similar refractive index as the refractive index of the light transmitting unit 210.

In addition, the optical sheet 200 according to the present embodiment is shown on one side of the light transmitting unit 210, that is, the opposite side to the base film 230, as shown in FIGS. 3 and 4 described later, the protective film 240. ) May be further provided. The protective film 240 serves to protect the optical sheet 200 until the optical sheet 200 is mounted on the filter 40, when the optical sheet 200 is mounted on the filter 40, It is common to separate from the optical sheet 200. However, the present invention is not limited thereto.

2A and 2B, the filter base FB is disposed on one surface of the optical sheet 200 and includes an electromagnetic wave shielding film 300, a hard coating layer 400, and an antireflection film 500. It is not limited. The stacking order of these 300, 400, and 500 in the filter base FB may be variously changed, and a material having two or more functions may be mixed in one layer to form a layer.

Electromagnetic wave shielding film 300 is responsible for the function to shield the electromagnetic wave. The electromagnetic wave shielding film 300 may have various configurations such as a conductive mesh layer, a metal thin film, a high refractive index transparent thin film, or a structure in which two or more of them are stacked. 2A and 2B, the electromagnetic shielding film 300 is illustrated as being composed of a single layer. However, the present invention is not limited thereto, and may be formed of a multilayer including at least two layers.

The hard coating layer 400 has scratch resistance to prevent the electromagnetic wave shielding film 300 or the anti-reflection film 500 described later from being damaged due to contact with an external material. The hard coating layer 400 may be tempered glass itself, or may include a polymer as a binder. In addition, the hard coating layer 400 may include an acrylic, urethane, epoxy, or siloxane polymer, or may include an ultraviolet curable resin such as an oligomer. In addition, a silica-based filler may be added to the hard coat layer 400 to improve the hardness.

The anti-reflection film 500 is responsible for minimizing eye fatigue of image display device users who watch for a long time by adjusting the transmittance of visible light. By arranging the antireflection film 500 in this way to adjust the visible light transmittance, in addition to the selective absorption effect of the visible light, it is possible to obtain an effect of improving the color reproduction range such as contrast ratio. 2A and 2B, the anti-reflection film 500 is illustrated as being composed of a single layer. However, the present invention is not limited thereto, and may be formed of a multilayer including at least two layers.

The anti-reflection film 500 has an antiphase with visible light that is incident from the outside and reflected from the surface of the anti-reflection film 500, and then is reflected from the interface between the anti-reflection film 500 and the hard coating layer 400. The antireflection effect is obtained by the principle of causing extinction interference phenomenon.

As the anti-reflection film 500, a mixture of indium tin oxide (ITO) and silicon oxide (SiO ₃ ), a mixture of nickel chromate (NiCr) and silicon oxide (SiO ₂ ), and the like may be cured and adhered. In addition, titanium oxide or a low refractive index special fluorine resin may be used as the antireflection film 500.

Hereinafter, specific configurations and effects of the light transmitting unit 210 and the external light absorbing unit 220 will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of an optical sheet according to an embodiment of the present invention, 4 is an enlarged view of a portion A of FIG. 3. The same reference numerals as in the above-described drawings indicate the same member or parts of the same member. 3 and 4 illustrate the case where the shape of the external light absorbing unit 220 is rectangular, but the present invention is not limited thereto.

The external light absorbing part 220 may include a thermoplastic or thermosetting resin in a roll molding method, a heat press method using a thermoplastic resin, or a light transmitting part 210 to which a groove g ₂₁₀ having a shape opposite to the pattern of the external light absorbing part 220 is transferred. It may be formed by an injection molding method of filling and molding. In addition, when the ultraviolet curable resin constituting the light transmitting unit 210 has an antireflection function, an electromagnetic shielding function, a color correction function, or a combination thereof, the optical sheet 200 may additionally perform these functions. have.

3 and 4, the optical sheet 200 according to the present embodiment includes a light transmitting unit 210, an external light absorbing unit 220, a base film 230, and a protective film 240. Here, the protective film 240 may be omitted by selection. And is the image light source-side surface has a surface roughness (SR ₂₁₀₎ of the light transmission portion 210 having, in the image light source-side surface of the external light absorption unit 220 is provided with a surface roughness (SR _220). As shown in FIG. 4, the image light source side surface roughness SR ₂₂₀ of the external light absorbing unit 220 is larger than the image light source side surface roughness SR ₂₁₀ of the light transmitting unit 210. By adjusting the surface roughness (SR ₂₁₀ , SR ₂₂₀ ) in this way, it is possible to obtain the optical sheet 200 with improved adhesion while maintaining high light transmittance and external light absorption.

The relative arrangement of the light transmitting unit 210, the external light absorbing unit 220, the base film 230, and the protective film 240 is as described above.

The external light absorbing part 220 may be arranged in various shapes such as a stripe shape, a matrix shape, or a wave shape. In addition, the plurality of external light absorbing units 220 may be spaced apart from each other to allow light to pass therebetween. In addition, in FIG. 3, the external light absorbing unit 220 is illustrated as one end surface of a rectangular shape, but the present invention is not limited thereto. The shape of the one end surface may be various shapes such as triangle, trapezoid, or pentagon.

Although not shown here, the optical sheet 200 according to the present embodiment may further include a prism portion disposed on one surface of the base film 230, that is, the surface opposite to the light transmitting portion 210. The prism portion may be formed of the same or similar material as that of the light transmitting portion 210. By providing the prism portion as described above, the optical sheet 200 may improve the external light absorption without a large change in the light transmittance, thereby increasing the contrast ratio and improving the resolution.

In this embodiment, the refractive index n ₂₂₀ of the external light absorbing part 220 may be adjusted to be larger than the refractive index n ₂₁₀ of the light transmitting part 210 (that is, n ₂₁₀ <n ₂₂₀ ). The difference in refractive index (Δn = n ₂₁₀ −n ₂₂₀ ) between the light transmitting unit 210 and the external light absorbing unit 220 is preferably in the range of −0.05 ≦ Δn <0. In this manner, the external light absorption in the optical sheet 200 may be increased to reduce the formation of a ghost. This will be described later. Here, the dual image is generated by the light emitted from the panel assembly 30 described above overlapping with the external ambient light that is not absorbed by the external light absorbing unit 220 and is reflected back to the outside, and the user of the image display apparatus is the same. This means that two images are recognized for the image.

As such, the principle of reducing or eliminating the dual phase by adjusting the difference in refractive index between the external light absorbing unit 220 and the light transmitting unit 210 will be described in more detail with reference to FIG. 4. Referring to FIG. 4, when external ambient light L ₁ , L ₂ , and L ₃ incident from the outside are incident on the external light absorbing part 220, the external ambient light is incident angle, that is, the light transmitting part 210 and the external light. Irrespective of the angles (0 °, θ1, θ2) formed with the normals of the interface between the absorbing parts 220, all of the external light absorbing parts 220 are absorbed by the external light absorbing part 220 without being reflected at the interface by the refractive index difference adjusted as described above. Will be. Therefore, the external light absorption rate is increased, thereby reducing the occurrence of double phases.

On the other hand, in the optical sheet of the present invention, the refractive index difference between the light transmitting portion 210 and the external light absorbing portion 220 (△ n = n ₂₁₀ -n ₂₂₀ ) may have a positive value, in this case at an angle smaller than the critical angle Since the image light incident on the interface between the light transmitting unit 210 and the external light absorbing unit 220 is totally reflected and projected toward the observer, an image different from an image made in the panel assembly is formed, that is, a ghost.

FIG. 5 is a partially separated perspective view illustrating a modified example of the optical sheet of FIG. 3 to prevent moiré phenomenon. FIG. The same reference numerals as in the above-described drawings indicate the same member or parts of the same member. Here, the moiré phenomenon refers to a phenomenon in which an interference fringe is formed when two or more periodic patterns overlap.

Referring to FIG. 5, the longitudinal direction (length) direction of the external light absorbing unit 220 and one side of the optical sheet 200 are not parallel to each other and have a bias angle α greater than 0 °. Although not shown here, the panel assembly 30 is formed with a plurality of cells that emit visible light constituting an image, and the cells are arranged in a stripe shape, a matrix shape, or a wave shape so that the external light of the optical sheet 200 is formed. It has an arrangement shape similar to the absorber 220. In this case, when the arrangement direction of the external light absorbing unit 220 and the cells coincide with each other, the moiré phenomenon occurs by overlapping both patterns. Thus, the longitudinal direction (length) direction of the external light absorbing unit 220 and the light transmitting unit ( By making the bias angle α formed by the long side of 210 longer than 0 °, the moiré phenomenon can be prevented by shifting both patterns when observed from the user side. Preferably, the bias angle α is 5 to 80 degrees.

The optical sheet or filter having the above configuration can be provided in the image display device, thereby improving the adhesion of the optical sheet, reducing the double image of the image display device and increasing the contrast ratio, and at the same time moire phenomenon Can be prevented.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

Example 1.

Forming rolls were formed in which protrusions having opposite shapes of a square shape were formed on the surface. Then, using a pattern roll equipment equipped with an ultraviolet device 100g of a low refractive index acrylic curing resin mixture on one surface between the optical PET film (Toyobo) having a thickness of 188㎛ constituting the forming roll and the base film 230 ( Refractive index: 1.48) was added slowly to cure. This obtained the light transmission part 210 of the refractive index 1.48 by which the protrusion part on the said molding roll was transferred in the groove shape. Scatter the carbon dispersion (refractive index: 1.49) prepared by mixing 2 g of carbon black in 100 g of the acrylic curing resin in the groove shape transferred and wiping several times using a Dr. blade made of soft plastic. By filling the groove shape evenly) to complete the external light absorbing unit 220 having a refractive index of 1.49. Then, the optical sheet 200 as shown in Figure 3 was prepared by curing with ultraviolet rays. Here, the pitch of the light transmitting portion 210 was 107.5㎛, the height of the external light absorbing portion 220 was 160㎛, the thickness of the light transmitting portion 210 was 200㎛. Here, the pitch of the light transmission unit 210 means the distance between the points corresponding to each other of the adjacent light transmission unit 210 partitioned by the external light absorbing unit 220.

As a result of measuring the prepared optical sheet 200 using a surface roughness analyzer, the surface roughness (SR ₂₁₀ ) of the light transmission unit 210 is 0.13㎛, the surface roughness (SR ₂₂₀ ) of the external light absorbing unit ₂₂₀ is 1.10㎛ It was.

Surface roughness was measured using an analytical instrument, Confocal Laser Scanning Microscope (CLSM, Model: Leica TCS SP2 RS), and the average surface roughness was measured by measuring 15 surface roughnesses of the external light absorbing part and the light transmitting part.

In the above described a preferred embodiment according to the present invention with reference to the drawings, but this is only exemplary, those skilled in the art can understand that various modifications and equivalent other embodiments are possible from this. There will be. Therefore, the protection scope of the present invention should be defined by the appended claims.

According to the present invention, an optical sheet capable of improving adhesion and improving contrast ratio in clear conditions and reducing double phase formation can be provided.

In addition, according to the present invention, an optical sheet capable of preventing the moiré phenomenon may be provided.

In addition, according to the present invention, a filter including the optical sheet may be provided.

In addition, according to the present invention, by providing the optical sheet or the filter it is possible to provide a clear image quality, improved resolution, and a moire phenomenon can be provided an image display device.

Claims (9)

A light transmitting portion having a plurality of groove portions disposed to be spaced apart from each other; And And a plurality of external light absorbing parts filled in the groove part and including a light absorbing material. Comprises a surface roughness (SR ₂₂₀₎ and the surface roughness (SR ₂₁₀₎ having a surface, each of the external light absorbing portion surface and the light transmitting portion corresponding to this, the surface roughness (SR ₂₂₀₎ provided on a surface of the external light absorbing portion The optical sheet larger than the surface roughness (SR ₂₁₀ ) provided on the surface of the light transmitting portion corresponding thereto. The method of claim 1, The surface roughness (SR ₂₂₀ ) of the external light absorbing portion is 0.15 to 5.0㎛, the optical sheet, characterized in that the surface roughness (SR ₂₁₀ ) of the light transmitting portion is 0.05 to 0.5㎛. The method of claim 2, The surface roughness of the external light absorbing portion (SR ₂₂₀ ) and the surface roughness (SR ₂₁₀ ) of the light transmitting portion satisfies the following conditions: 0.1 ≦ SR ₂₂₀ −SR ₂₁₀ ≦ 0.45 μm. The method of claim 1, One end surface of the external light absorbing portion is triangular, rectangular or trapezoidal, characterized in that the optical sheet. The method of claim 1, And the external light absorbing portion is arranged in a stripe shape, a matrix shape, or a wave shape. The method of claim 1, Optical sheet, characterized in that the longitudinal direction of the external light absorbing portion and one side of the optical sheet is not parallel. The method of claim 1, An optical sheet comprising a high resolution sheet. A filter for an image display device, comprising the optical sheet according to any one of claims 1 to 7, and a filter base. An image display device comprising the optical sheet according to any one of claims 1 to 7.

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