KR102296167B1 - Optical film and optical display device comprising the same - Google Patents

Abstract

The present disclosure relates to an optical film having a plurality of patterns as a hollow part and a protrusion part surrounding an outer circumferential surface of the hollow part, and an optical display device including the same. In the optical film, an air gap is formed not only between a diffusion sheet and the first prism sheet but also in the hollow part by impregnating the protrusion part of the pattern in the first adhesive layer of the first prism sheet during bonding between the sheets. Accordingly, optical properties such as luminance and reliability may be improved. The optical film includes a diffusion sheet, and a first prism sheet and a second prism sheet that are sequentially laminated on the upper surface of the diffusion sheet. The diffusion sheet includes a diffusion base layer and a plurality of patterns formed on an upper surface of the diffusion base layer and spaced apart from each other. The plurality of patterns may include the hollow part positioned in the central region of the pattern and a protrusion part that surrounds an outer circumferential surface of the hollow part and protrudes in a direction perpendicular to the upper surface of the diffusion base layer.

Description

Optical film and optical display device including the same

The present disclosure relates to an optical film and an optical display device including the same.

Unless otherwise indicated herein, the material described in this section is not prior art to the claims of this application, and inclusion in this section is not an admission that it is prior art.

In general, since an optical display device controls the amount of light by reflecting or transmitting light through an optical film, an optical display device using a backlight unit is greatly affected by the performance of the optical film. Such an optical film includes a prism sheet and a diffusion sheet, and the diffusion sheet is composed of a substrate layer, and a light diffusion layer formed on one surface and the other surface of the substrate layer. The prism sheet and the diffusion sheet can be bonded by a gravure coating method using a UV adhesive. In this case, as shown in FIG. 1 , the optical properties such as transmittance and luminance of the optical sheet are obtained as the light diffusion layer is buried in the adhesive and the air gap is lost. There is a problem of loss.

As a method for improving this problem, Patent Document 1 discloses a technique in which a predetermined bonding pattern is formed on the lower portion of the upper optical sheet to reduce the bonding area with the lower optical sheet so that the area on which light is condensed does not decrease. .

However, in Patent Document 1, the height of the adhesive layer penetrated by the apex is low and has irregularities, so that the apex does not sufficiently penetrate the adhesive layer, thereby reducing adhesive strength.

Republic of Korea Patent Registration No. 10-1268085 (2013.05.21)

It is an object to provide an optical film having excellent adhesion and luminance at the same time and an optical display device including the same.

According to an embodiment of the disclosure, the optical film includes a diffusion sheet and a first prism sheet and a second prism sheet sequentially stacked on the upper surface of the diffusion sheet, and the diffusion sheet includes a diffusion substrate layer and the diffusion substrate A plurality of patterns formed on the upper surface of the layer and disposed spaced apart, wherein the plurality of patterns surround a hollow portion positioned in the central region of the pattern and an outer circumferential surface of the hollow portion, and protrude in a direction perpendicular to the upper surface of the diffusion base layer and a protrusion formed therein.

In addition, the first prism sheet includes a first base layer, a first pattern layer protruding from an upper surface of the first base layer, and a first adhesive layer formed on a lower surface of the first base layer, and an upper portion of the protrusion is The first adhesive layer may be impregnated and bonded.

In addition, the cross-sectional area of the protrusion may increase from the top to the bottom.

In addition, the upper diameter of the protrusion may be 1 ~ 6㎛.

In addition, the height of the protrusion may be 1 ~ 15㎛.

In addition, the outer diameter of the protrusion may be inversely proportional to the inner diameter.

In addition, the lower outer diameter of the protrusion may be 25 ~ 35㎛.

Also, a distance between adjacent patterns among the plurality of patterns may be 20 to 60 μm.

In addition, the diffusion sheet and the first prism sheet and the second prism sheet may be integrally formed by a lamination method.

According to another embodiment of the present disclosure, the optical display device includes a diffusion sheet and a first prism sheet and a second prism sheet sequentially stacked on an upper surface of the diffusion sheet, wherein the diffusion sheet includes a diffusion base layer and the diffusion sheet A plurality of patterns formed on the upper surface of the base layer and arranged to be spaced apart, wherein the plurality of patterns surround a hollow portion positioned in the central region of the pattern and an outer circumferential surface of the hollow portion, in a direction perpendicular to the upper surface of the diffusion base layer and a diffusion sheet interposed with a protrusion formed to protrude.

According to an embodiment disclosed in the present specification, since a plurality of patterns are provided with a hollow portion and a protrusion surrounding the outer circumferential surface of the hollow portion, the protrusion of the pattern is impregnated in the first adhesive layer of the first prism sheet when the sheets are adhered to each other to form a diffusion sheet and a first adhesive layer. 1 An air gap may be formed not only between the prism sheets but also in the hollow portion, thereby improving optical properties such as luminance and reliability.

1 is a diagram illustrating an impregnation phenomenon of a light diffusion layer.
2 is a schematic diagram illustrating an optical display device according to an embodiment of the disclosure in the present specification.
3 is a perspective view showing an optical film according to an embodiment of the content disclosed in the present specification.
4 is a cross-sectional view taken along line A-A' of FIG. 3 .
5 is a cross-sectional view illustrating a diffusion sheet according to an embodiment of the disclosure in the present specification.
Figure 6a is a perspective view showing a diffusion sheet according to an embodiment of the content disclosed herein, Figure 6b is a perspective view showing another form of the diffusion sheet.

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

2 is a schematic diagram illustrating an optical display device according to an embodiment of the disclosure in the present specification.

The optical display device 1 may include a liquid crystal panel 10 , a backlight unit 20 , a guide panel 30 , a lower cover 40 , and an upper case 50 .

The liquid crystal panel 10 includes a color filter array substrate, a thin film transistor array substrate, and a liquid crystal layer interposed therebetween. can be formed

The backlight unit 20 includes a light source 21 , a light guide plate 23 for guiding light generated from the light source, a reflective sheet 24 disposed under the light guide plate 23 , and an optical device disposed on the light guide plate 23 . The film 100 may be included.

The light source 21 is to generate light, and any one of a beneficiation type lamp, a surface light type lamp, a cold cathode fluorescent lamp, an external electrode fluorescent lamp, and a light emitting diode device can be selected and used. The light source cover 22 may be further provided for the purpose of protecting the light source.

The optical film 100 may be formed by integrating a plurality of sheets, and includes a diffusion sheet 110 , a first prism sheet 120 , and a second prism sheet 130 , and the diffusion sheet 110 is a light guide plate. The light incident from 23 may be diffused and supplied to the first prism sheet 120 and the second prism sheet 130 .

The light guide plate 23 serves to guide the light emitted from the light source 21 to the optical film 100, is not easily deformed or broken due to its high strength, and can be formed of polymethymethacrylate with good transmittance. have.

The reflective sheet 24 serves to reflect the light generated from the light source and supply it in the direction of the optical film 100 .

The guide panel 30 may fix and support the liquid crystal panel 10 and the backlight unit 20 .

The lower cover 40 accommodates the liquid crystal panel 10 and the backlight unit 20 , and may be coupled to the upper case 50 .

3 is a perspective view showing an optical film according to an embodiment of the content disclosed herein, and FIG. 4 is a cross-sectional view taken along line A-A' of FIG. 3 .

Referring to FIG. 3 , the optical film 100 may include a diffusion sheet 110 and a first prism sheet 120 and a second prism sheet 130 that are sequentially stacked on the upper surface of the diffusion sheet 110 . can The optical film 100 can improve reliability while minimizing the final thickness by integrating a plurality of sheets by lamination processing.

The first prism sheet 120 is laminated on the upper surface of the diffusion sheet 110 , and a first base layer 121 , a first pattern layer 122 protruding from the upper surface of the first base layer 121 , and A first adhesive layer 123 formed on a lower surface of the first base layer 121 may be included.

The second prism sheet 130 is stacked on the first prism sheet 120 in a vertical pattern direction, and a second base layer 131 and a second pattern layer protruding from the upper surface of the second base layer 131 . 132 and a second adhesive layer 133 formed on the lower surface of the second base layer 131 .

The first base layer 121 and the second base layer 131 may be made of a material that can transmit light, and specifically, a polycarbonate-based, polysulfone-based, polyacrylate ( At least one material selected from the group consisting of polyacrylate) series, polystyrene series, polyvinylchloride series, polyvinylalcohol series, polynorbornene series, and polyester series can be made with

The first pattern layer 122 and the second pattern layer 132 may be formed perpendicular to each other, and at least one pattern selected from the group consisting of a prism pattern, a lens pattern, a pyramid pattern, and an emboss pattern, preferably a prism It can be formed in a pattern.

Meanwhile, in FIG. 4 , a prism pattern having a vertical cross section of the first pattern layer 122 and the second pattern layer 132 is illustrated as an example, but the present invention is not limited thereto. It may be formed in any one shape.

The first adhesive layer 123 and the second adhesive layer 133 may include at least one resin selected from the group consisting of an epoxy acrylate resin and a urethane acrylate resin, and a photoinitiator or It may further include a filler. The photoinitiator is for curing the resin and the photocurable monomer, and may include a conventional photoinitiator. Specifically, one or more selected from the group consisting of phosphine oxide and cyclohexylphenyl ketone may be used, and may be included in an amount of 1 to 10 parts by weight, preferably 3 to 7 parts by weight, based on 100 parts by weight of the resin. have. When the above-mentioned range is satisfied, the first adhesive layer 123 and the second adhesive layer 133 may be completely cured, and a residual amount of the photoinitiator may remain to prevent deterioration of the transparency of the optical film 100 .

Figure 5 is a cross-sectional view showing a diffusion sheet according to an embodiment of the content disclosed herein, Figure 6a is a perspective view showing a diffusion sheet according to an embodiment of the content disclosed herein, Figure 6b is another form of the diffusion sheet is a perspective view showing

Referring to FIG. 5 , the diffusion sheet 110 may include a diffusion base layer 111 and a plurality of patterns 115 formed on the upper surface of the diffusion base layer 111 and spaced apart from each other. In addition, a light diffusion layer 113 may be formed on the lower surface of the diffusion base layer 111 .

Since the diffusion base layer 111 has to transmit light, it is preferably colorless and transparent, polyethyleneterephthalate, polyethylenenaphthalate, acrylic resin, polycarbonate, polystyrene ), polyolefin (polyolefin), cellulose acetate, and may be made of one or more synthetic resins selected from the group consisting of waterproof vinyl chloride (weather-resistant vinyl chloride), 10 ~ 300㎛, preferably 20 ~ It may be formed to a thickness of 200 μm, but is not limited thereto.

The plurality of patterns 115 and the light diffusion layer 113 diffuse the light transmitted from the bottom and at the same time scatter the incident light to serve as a light shield to dilute the bright and dark areas, and to form an air gap and prevent light scattering and scattering. It may be configured in a form capable of increasing luminance by maximizing refraction. The plurality of patterns 115 may be made of one or more materials selected from the group consisting of a thermosetting resin and an ultraviolet curable resin, and specifically, an acrylic resin, a urethane-based resin, a polyester-based resin, an epoxy acrylate-based resin, and a urethane acrylic resin. It may be made of at least one material selected from the group consisting of a rate-based resin and a silicone acrylate-based resin.

The plurality of patterns 115 surround the hollow portion 116 positioned in the central region of the pattern 115 and the outer circumferential surface of the hollow portion 116 , and are formed to protrude in a direction perpendicular to the upper surface of the diffusion substrate layer 111 . It may include a protrusion 117 that is.

The hollow portion 116 is located in a relatively central region of the pattern 115, and the size of the hollow portion 116 may be increased in proportion to the height H or the inner diameter d1 of the protrusion 117, which will be described later. .

In the present specification, the hollow part 116 is an empty space in which air is contained and means an air gap.

The protrusion 117 is tapered from the top to the bottom, and specifically, the outer surface may be tapered to have an inclined surface. The transverse cross-sectional area of the protrusion 117 may increase from the top to the bottom, for example, the upper diameter (ℓ1) is formed smaller than the lower diameter (ℓ2), the upper diameter (ℓ1) is 1 ~ 6㎛, preferably may be formed in a range of 2 to 5 μm. In addition, the upper surface of the protrusion 117 may have a curved curved surface. The height H of the protrusion 117 may be in the range of 1 to 15 μm, preferably 2 to 10 μm.

When the upper diameter ℓ1 of the protrusion 117 satisfies the above-mentioned range, the upper portion of the protrusion 117 is not deformed and the upper portion of the protrusion 117 is impregnated with the first adhesive layer 123 to form the protrusion. It is possible to minimize the loss of the slope of (117). Accordingly, the luminance may be increased by condensing more light transmitted from the lower portion.

When the height H of the protrusion 117 is less than 1 μm, it is difficult to secure an air gap by impregnating an upper portion of the protrusion 117 in the first adhesive layer 123 , and when it exceeds 15 μm, the air gap is sufficiently closed Although it can be secured, it is not preferable because the final thickness of the optical film 100 may also be increased.

For example, the inner diameter d1 of the protrusion 117 may become smaller from the upper part to the lower part, and in this case, the upper inner diameter d1 of the protrusion part 117 is 10 to 20 µm, preferably 13 to 17 µm, more preferably It may be 15 μm. The outer diameter d2 of the protrusion 117 may be inversely proportional to the above-mentioned inner diameter d1, and may increase from the upper part to the lower part, and the lower outer diameter d2 of the protrusion part 117 is 25 to 35 μm, preferably may be 28 to 32 μm, more preferably 30 μm.

If the upper inner diameter d1 of the protrusion 117 is less than 10 μm, the area of the hollow portion 116 is narrowed, so it may be difficult to secure an air gap between the diffusion sheet 110 and the first prism sheet 120 , 20 If it exceeds ㎛, the adhesion between the diffusion sheet 110 and the first prism sheet 120 is weak, so that the diffusion sheet 110 can be easily separated from the first prism sheet 120, which is not preferable.

If the lower outer diameter d2 of the protrusion 117 is less than 25 μm, it may be difficult to stably secure an air gap between the diffusion sheet 110 and the first prism sheet 120, and when it exceeds 35 μm, the diffusion substrate Since the number of patterns 115 that can be formed on the layer 111 decreases, it may be difficult to implement a desired level of luminance.

Referring to FIG. 6A , the distance between adjacent patterns 115 ′ among the plurality of patterns 115 may be 20 to 60 μm, preferably 30 to 50 μm, and in other words, adjacent ones of the plurality of patterns 115 . The distance between the protrusions 117' to The distance between the central regions C' of the hollow portion 116' of the pattern 115' may be 20 to 100 μm, preferably 40 to 80 μm, and more preferably 50 to 70 μm. The plurality of patterns 115 may all have the same size and shape. Although FIG. 6A shows patterns 115 and 115' having a horizontal cross-sectional area with the ground in a donut shape, the present invention is not limited thereto, and a hexagonal pattern 215 as shown in FIG. 6B is also possible.

Although the preferred embodiment of the present invention has been described with reference to the accompanying drawings, the embodiments described in the present specification and the configuration shown in the drawings are only the most preferred embodiment of the present invention and represent all of the technical spirit of the present invention. Therefore, it should be understood that there may be various equivalents and modifications that can be substituted for them at the time of filing the present application. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the detailed description, and the meaning and scope of the claims and their All changes or modifications derived from the concept of equivalents should be construed as being included in the scope of the present invention.

1: optical display device 10: liquid crystal panel
20: backlight unit 21: light source
22: light source cover 23: light guide plate
24: reflective sheet 30: guide panel
40: lower cover 50: upper case
100: optical film 110: diffusion sheet
115, 115, 215': pattern 116, 116': hollow
117, 117': protrusion 120: first prism sheet
130: second prism sheet

Claims (10)

diffusion sheet; and
A first prism sheet and a second prism sheet are sequentially stacked on the upper surface of the diffusion sheet;
The diffusion sheet
diffusion base layer; and
A plurality of patterns formed on the upper surface of the diffusion base layer and spaced apart from each other;
The plurality of patterns
a hollow part located in the central region of the pattern; and
Surrounding the outer circumferential surface of the hollow portion and including a protrusion formed to protrude in a direction perpendicular to the upper surface of the diffusion base layer, the height of the protrusion is 1 ~ 15㎛ optical film.
According to claim 1,
The first prism sheet
a first base layer;
a first pattern layer protruding from an upper surface of the first base layer; and
A first adhesive layer formed on the lower surface of the first base layer,
An upper portion of the protrusion is impregnated with the first adhesive layer and coupled to the optical film.
According to claim 1,
The optical film, characterized in that the cross-sectional area of the protrusion increases from the top to the bottom.
4. The method of claim 3,
The upper diameter of the protrusion is an optical film, characterized in that 1 ~ 6㎛.
delete According to claim 1,
The optical film, characterized in that the outer diameter of the protrusion is inversely proportional to the inner diameter.
7. The method of claim 6,
The lower outer diameter of the protrusion is an optical film, characterized in that 25 ~ 35㎛.
According to claim 1,
The optical film, characterized in that the distance between the adjacent patterns of the plurality of patterns 20 ~ 60㎛.
According to claim 1,
The diffusion sheet and the first prism sheet and the second prism sheet are optical film, characterized in that formed integrally by a lamination process.
A diffusion sheet and a first prism sheet and a second prism sheet that are sequentially laminated on the upper surface of the diffusion sheet,
The diffusion sheet includes a diffusion substrate layer and a plurality of patterns formed on the upper surface of the diffusion substrate layer and spaced apart, wherein the plurality of patterns surround a hollow portion positioned in the central region of the pattern and an outer peripheral surface of the hollow portion, An optical display device comprising an optical film protruding in a direction perpendicular to the upper surface of the diffusion base layer and interposed with a protrusion having a height of 1 to 15 μm.

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