KR20090124518A - Optical sheet - Google Patents

Abstract

PURPOSE: An optical sheet is provided to improve the photonic efficiency of the backlight unit and display quality of the liquid crystal display. CONSTITUTION: The reflection-type polarizing film comprises the reflection-type polarizing film layer(110) and the first diffusion layer(140). The first diffusion layer is located in one-side of the reflection-type polarizing film layer. The first diffusion layer comprises a plurality of first spreading particles(145). By laminating a plurality of layers having the different refractive index the reflection-type polarizing film layer is formed. The reflection-type polarizing film layer transmits only the specific polarized light. The reflection-type polarizing film layer reflects the other light except for the specific polarized light. The reflection-type polarizing film layer comprises the layer aligned to isotropy and the layer aligned to anisotropic. The first diffusion layer is located in one-side of the reflection-type polarizing film layer. The maximum surface roughness of the reflection-type polarizing film layer is 0.1~5μm.

Description

Optical Sheet

The present invention relates to an optical sheet.

With the development of information technology, the market for a display device, which is a connection medium between a user and information, is growing. Accordingly, flat panel displays (FPDs) such as liquid crystal displays (LCDs), organic light emitting diodes (OLEDs), and plasma display panels (PDPs) may be used. Usage is increasing. Among them, a liquid crystal display capable of realizing high resolution and capable of miniaturization as well as a large size is widely used.

Here, the liquid crystal display device is classified into a light receiving display device. Such a liquid crystal display may display an image by receiving a light source from a backlight unit disposed under the liquid crystal panel.

The backlight unit may include a light source and an optical film layer in order to provide efficient light to the liquid crystal panel. Here, the optical film layer may include a diffusion sheet, an optical sheet, a protective sheet and the like.

On the other hand, when mounting and fixing the optical sheet to the liquid crystal display device, if both sides of the optical sheet is too flat, a space is formed after the optical sheet is mounted on the liquid crystal display device. In this case, the optical sheet may be distorted due to external impact or other physical handling, or may cause the optical sheet to cry in severe cases.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems of the background art is to provide a surface roughness on at least one side of both sides of the optical sheet to prevent the optical sheet from twisting or crying after mounting and fixing the optical sheet to the liquid crystal display device. This is to maintain the light efficiency of the backlight unit. In addition, by preventing the above problems, it is possible to solve the problem of deterioration of the display quality of the liquid crystal display device and increase the reliability of the product.

The present invention as a problem solving means described above, the reflective polarizing film layer; And a first diffusion layer positioned on one surface of the reflective polarizing film layer, wherein the maximum surface roughness of at least one side of both sides of the reflective polarizing film layer is 0.1 to 5 μm.

It may include a second diffusion layer located on the other surface of the reflective polarizing film layer.

The maximum surface roughness of at least one side of both sides of the first diffusion layer may be 0.1 to 5㎛.

The maximum surface roughness of at least one side of both sides of the second diffusion layer may be 0.1 to 5㎛.

The reflective polarizing film layer may have a thickness of 100 μm to 250 μm.

The reflective polarizing film layer may include a plurality of layers having different refractive indices.

The first diffusion layer and the second diffusion layer may be attached to the reflective polarization layer by an adhesive.

On the other hand, the present invention in another aspect, the base film layer; It includes a plurality of protrusions located on one surface of the base film layer, it provides an optical sheet, characterized in that the maximum surface roughness of at least one side of both sides of the base film layer is 0.1 ~ 5㎛.

The base film layer may include a protective layer located on the other surface.

The maximum surface roughness of at least one side of both sides of the protective layer may be 0.1 to 5㎛.

The protrusion may include a prism, a lenticular lens, and a micro lens.

The prism is a prism including a plurality of peaks and valleys, and the height of the peaks may vary along the longitudinal direction of the prism.

The prism is a prism including a plurality of hills and valleys, and the height of the hills can oscillate left and right.

The plurality of protrusions may include a plurality of beads.

On the other hand, the present invention, the light source; An optical sheet positioned on the light source; And a liquid crystal panel positioned on the optical sheet, wherein the optical sheet provides a liquid crystal display device having a maximum surface roughness of 0.1 to 5 μm on at least one side of both sides.

The present invention has an effect of maintaining the light efficiency of the backlight unit by preventing surface distortion or crying after mounting and fixing the optical sheet to the liquid crystal display device by placing a surface roughness on at least one side of both sides of the optical sheet. . In addition, by preventing the above problems, there is an effect of solving the problem of deterioration of the display quality of the liquid crystal display device and increasing the reliability of the product.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

First Embodiment

1 is a cross-sectional view of an optical sheet according to a first exemplary embodiment of the present invention, and FIG. 2 is an enlarged view of region X1 of FIG. 1.

1 and 2, the optical sheet according to the first embodiment of the present invention uses a reflective polarizing film as an example.

The reflective polarizing film may include a first diffusing layer 140 including a reflective polarizing film layer 110 and a plurality of first diffusing particles 145 positioned on one surface of the reflective polarizing film layer 110. .

Reflective polarizing film layer 110 is a multi-layer that can stretch a plurality of layers having different refractive indices in one direction and laminated so that the stretching directions coincide with each other to transmit only specific polarization and reflect other light. It has a thin film structure.

In more detail, the reflective polarizing film layer 110 includes an isotropically oriented layer and a plurality of anisotropically oriented layers. The thickness of the reflective polarizing film layer 110 may have a range of 100 μm to 250 μm, but is not limited thereto.

Here, the isotropic alignment layer may be PMMA (Polymethly Methacrylate) having excellent transparency, good weather resistance, high hardness, and excellent surface gloss, but is not limited thereto. The anisotropic alignment layer may be a polyester having a high refractive index. It is not limited to this.

Accordingly, the reflective polarizing film layer 110 may emit specific light and continuously reflect the specific light so that the maximum light can be used without missing light.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, at the time of surface forming, the maximum surface roughness (pp1) of at least one side of both sides of the optical sheet may have a range of 0.1 to 5 μm.

Here, if the surface roughness (pp1) has a range of 0.1 to 5㎛, it is easy to mount on the liquid crystal display device and there is no problem of crying the optical sheet even after fixing. Here, when the surface roughness pp1 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the surface roughness (pp1) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is warped or crying after mounting and fixing the optical sheet to the liquid crystal display. There is an effect of maintaining the light efficiency of the backlight unit by preventing the.

Second Embodiment

3 is a cross-sectional view of an optical sheet according to a second exemplary embodiment of the present invention, and FIG. 4 is an enlarged view of region X2 of FIG. 3.

3 and 4, the optical sheet according to the second embodiment of the present invention uses a reflective polarizing film as an example.

The reflective polarizing film includes a first diffusing layer 240 and a reflective polarizing film including a plurality of first diffusing particles 245 disposed on one surface of the reflective polarizing film layer 210 and the reflective polarizing film layer 210. The second diffusion layer 250 may include a plurality of second diffusion particles 255 positioned on the other surface of the layer 210.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, the maximum surface roughness (pp2) of at least one side of both sides of the optical sheet at the time of surface shaping may have a range of 0.1 ~ 5㎛.

Here, if the surface roughness (pp2) is in the range of 0.1 to 5㎛, it is easy to mount on the liquid crystal display device and there is no problem of crying the optical sheet even after fixing. Here, when the surface roughness pp2 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the surface roughness (pp2) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is distorted or crying after mounting and fixing the optical sheet to the liquid crystal display. There is an effect to maintain the light efficiency of the backlight unit.

Third Embodiment

5 is a cross-sectional view of an optical sheet according to a third exemplary embodiment of the present invention, and FIG. 6 is an enlarged view of region X3 of FIG. 5.

As shown in FIGS. 5 and 6, the optical sheet according to the third exemplary embodiment of the present invention may have a plurality of protrusions as prisms.

The prism sheet may be disposed on one surface of the base film layer 310 and the base film layer 310 and may include a plurality of protrusions 330. Here, the plurality of protrusions 330 may form a prism shape including a peak 330a and a valley 330b, and the distance P between the peak 330a and the peak 330a and the angle of the peak 330a ( A) may have a constant shape.

Here, the base film layer 310 may be transparent to transmit the light emitted from the light source. To this end, the base film layer 310 may be formed of a transparent material. The material of the base film layer 310 may be any one selected from the group consisting of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy.

The base film layer 310 may have a predetermined thickness, for example, a thin thickness of 10 μm to 1000 μm. Thus, when the thickness of the base film layer 310 is formed to 10㎛ or more, it can be thin within the limit to secure the mechanical strength and thermal stability of the sheet. When the thickness of the base film layer 310 is formed to 1000 μm or less, mechanical strength and heat resistance may be maximized within the limit of securing flexibility of the sheet. And when formed in the range of such a thickness can exhibit excellent performance in terms of processability as well as have a property that can be bent like a film.

The protrusion 330 may be formed of a resin such as acrylic, urethane, polyester, or the like, and the protrusion 330 may be formed of a material capable of increasing light condensing of light incident through the base film layer 310.

Here, the base film layer 310 and the protrusion 330 may be attached by the adhesive 315, but is not limited thereto.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, the maximum surface roughness (pp3) of at least one side of both sides of the optical sheet during the surface forming may have a range of 0.1 ~ 5㎛.

Here, when the maximum surface roughness (pp3) has a range of 0.1 to 5㎛, it is easy to mount on the liquid crystal display device and there is no problem of crying the optical sheet even after fixing. Here, when the maximum surface roughness pp3 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the maximum surface roughness (pp3) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is distorted or crying after mounting and fixing the optical sheet to the liquid crystal display device. There is an effect of maintaining the light efficiency of the backlight unit by preventing the.

7 is a cross-sectional view of an optical sheet according to a modified embodiment of the third embodiment of the present invention, and FIG. 8 is an enlarged view of region X4 of FIG. 7.

As shown in FIGS. 7 and 8, the optical sheet according to the modified embodiment of the third embodiment of the present invention may have a plurality of protrusions as prisms.

The prism sheet is disposed on one surface of the base film layer 310 and the base film layer 310, and is disposed on the other surface of the plurality of protrusions 330 and the base film layer 310, and includes a plurality of diffusion particles 345. It may include layer 340. Here, the plurality of protrusions 330 may form a prism shape including a peak 330a and a valley 330b, and the distance P between the peak 330a and the peak 330a and the angle of the peak 330a ( A) may have a constant shape.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, the maximum surface roughness (pp4) of at least one side of both sides of the optical sheet at the time of surface shaping may have a range of 0.1 ~ 5㎛.

Here, when the maximum surface roughness (pp4) has a range of 0.1 to 5㎛, it is easy to mount on the liquid crystal display device and there is no problem of crying the optical sheet even after fixing. Here, when the maximum surface roughness pp4 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the maximum surface roughness (pp4) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is warped or crying after mounting and fixing the optical sheet to the liquid crystal display device. There is an effect of maintaining the light efficiency of the backlight unit by preventing the.

Meanwhile, the optical sheet described above with reference to FIGS. 5 to 8 may have various shapes of a plurality of protrusions forming a prism shape.

Therefore, the plurality of protrusions 330 may be formed in any one of the following shapes as well as the shape described above.

9 to 16 illustrate various examples of protrusions.

9, the distance P between the mountains forming the prism shape and the angle A of the mountains may be regularly different from each other. The protrusion 330 having such a shape may have a diffusion effect in which a change in refractive index of incident light occurs differently in a predetermined region.

The protrusion 330 illustrated in FIG. 10 may be formed in a form in which the distance P between the mountains forming the prism shape and the angle A of the mountain are small, that is, the densities of the mountains and the valleys are high. The protrusion 330 having such a shape may have an effect of increasing the straightness rather than the light diffusion effect because the refractive index of the incident light occurs densely.

The protrusion 330 illustrated in FIG. 11 may have a random shape of a peak and a valley forming a prism shape. The protrusion 330 having such a shape may have a diffusion effect in which a refractive angle of incident light occurs randomly.

9 to 11, the prism shape included in the protrusions 330 illustrated in FIGS. 9 to 11 may have one or more distances (P) between the mountains and one or more angles (A) of the mountains, and thus, the shape of the valleys may also change. . Here, the distance between the mountains (P) may have a 20 ㎛ ~ 60 ㎛, the angle of the mountains (A) may have a 70 ° ~ 110 °, the overall thickness of the protrusion 330 is 20 ㎛ ~ 40 ㎛ But it is not limited thereto.

The protrusion 330 illustrated in FIG. 12 may have a shape of a peak and a valley forming a prism shape in a streamline shape instead of a straight line shape. The protrusion 330 having such a shape may have a diffusion effect in which a refractive angle of incident light is wider.

9 to 12 illustrate various cross sections of the protrusion 330, that is, the prism. However, the shapes of the protrusions 330 are different from each other on a plane or a side surface. Referring to FIG. 13, the height of the peaks of the prism may be changed to the left and right in the longitudinal direction of the prism. In addition, referring to FIG. 14, the height of the peak of the prism may be varied up and down in the longitudinal direction of the prism. In addition, referring to FIG. 15, a part of the acid of the prism may have a groove recessed with a pattern oscillating left, right, or up and down. In addition, referring to FIG. 16, the height of the peak of the prism may have a pattern that vibrates vertically and horizontally in the longitudinal direction of the prism.

Fourth Embodiment

17 is a cross-sectional view of an optical sheet according to a fourth exemplary embodiment of the present invention, and FIG. 18 is an enlarged view of region X5 of FIG. 17.

As shown in FIGS. 17 and 18, the optical sheet according to the fourth exemplary embodiment of the present invention may be a lenticular lens having a plurality of protrusions.

The lenticular lens may be positioned on one surface of the base film layer 410 and the base film layer 410 and may include a plurality of protrusions 430. Here, the plurality of protrusions 430 may have a shape in which hemispherical lenses are arranged in one direction.

The optical sheet may further include a protective layer 440 including a plurality of diffusion particles 445, in other words a back coating layer, to protect the other surface of the base film layer 410 as shown.

Here, the base film layer 410 may be transparent to transmit the light emitted from the light source. To this end, the base film layer 410 may be formed of a transparent material. The material of the base film layer 410 may be any one selected from the group consisting of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy.

The base film layer 410 may have a predetermined thickness, for example, a thin thickness of 10 μm to 1000 μm. Thus, when the thickness of the base film layer 410 is formed to 10㎛ or more, it can be thin within the limit to secure the mechanical strength and thermal stability of the sheet. When the thickness of the base film layer 410 is formed to 1000 μm or less, mechanical strength and heat resistance may be maximized within the limit of securing flexibility of the sheet. And when formed in the range of such a thickness can exhibit excellent performance in terms of processability as well as have a property that can be bent like a film.

The protrusion 430 may use a resin such as acrylic, urethane, polyester, or the like, and the protrusion 430 may be formed of a material capable of increasing light condensing of the light incident through the base film layer 410.

Here, the base film layer 410 and the protrusion 430 may be attached by the adhesive 415, but is not limited thereto.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, the maximum surface roughness (pp5) of at least one side of both sides of the optical sheet during the surface forming may have a range of 0.1 ~ 5㎛.

Here, when the maximum surface roughness (pp5) has a range of 0.1 to 5㎛, it is easy to mount on the liquid crystal display device and there is no problem of crying the optical sheet even after fixing. Here, when the maximum surface roughness pp5 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the maximum surface roughness (pp5) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is warped or crying after mounting and fixing the optical sheet to the liquid crystal display device. There is an effect of maintaining the light efficiency of the backlight unit by preventing the.

Fifth Embodiment

19 is a cross-sectional view of an optical sheet according to a fifth exemplary embodiment of the present invention, and FIG. 20 is an enlarged view of region X6 of FIG. 19.

19 and 20, the optical sheet according to the fifth embodiment of the present invention has a plurality of protrusions as an example of a micro lens.

The micro lens may be disposed on one surface of the base film layer 510 and the base film layer 510 and may include a plurality of protrusions 530. Here, the plurality of protrusions may have a shape in which hemispherical micro lenses are randomly arranged.

The optical sheet may further include a protective layer 540 including a plurality of diffusion particles 545, in other words a back coating layer, to protect the other surface of the base film layer 510 as shown.

Here, the base film layer 510 may be transparent to transmit the light emitted from the light source. To this end, the base film layer 510 may be formed of a transparent material. The material of the base film layer 510 may be any one selected from the group consisting of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy.

The base film layer 510 may have a predetermined thickness, for example, a thin thickness of 10 μm to 1000 μm. When the thickness of the base film layer 510 is 10 μm or more, the thickness of the base film layer 510 can be reduced within the limit of securing mechanical strength and thermal stability of the sheet. When the thickness of the base film layer 510 is formed to 1000 μm or less, mechanical strength and heat resistance may be secured to the maximum within the limit of securing flexibility of the sheet. And when formed in the range of such a thickness can exhibit excellent performance in terms of processability as well as have a property that can be bent like a film.

The protrusion 530 may be formed of a resin such as acrylic, urethane, polyester, or the like, and the protrusion 530 may be made of a material capable of increasing light condensing of light incident through the base film layer 510.

Here, the base film layer 510 and the protrusion 530 may be attached by the adhesive 515, but is not limited thereto.

Here, the degree of diffusion, the degree of refraction, the light condensation, etc. may vary depending on the size and the density of the microlenses as the protrusions 530. The diameter of the micro lens, which is the protrusion 530, may be formed to be 20 μm to 200 μm, but is not limited thereto. Further, the distribution of the microlenses in the protrusion 530 may be formed to have 80% to 90% or more, but is not limited thereto. In addition, the diameter of the microlens, which is the protrusion 530, may be located in a random shape with a random size.

The optical sheet having such a structure is subjected to a process of forming the surfaces of both sides so as to prevent the problem of twisting or crying to either side when mounting and fixing to the liquid crystal display device. The method that can be used during surface forming may be used, such as extrusion or injection, but is not limited thereto. However, at the time of surface forming, the maximum surface roughness (pp6) of at least one side of both sides of the optical sheet may have a range of 0.1 to 5 μm.

Here, when the maximum surface roughness (pp6) has a range of 0.1 ~ 5㎛, it is easy to mount on the liquid crystal display device and the problem of crying the optical sheet even after fixing. Here, when the maximum surface roughness pp6 exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet increases. In such a case, when the optical sheet is mounted on the liquid crystal display device, it becomes difficult to mount the optical sheet. Nevertheless, if the optical sheet is fixed after being forcedly mounted on the liquid crystal display device, the optical sheet may cry.

However, when the maximum surface roughness (pp6) of at least one side of both sides of the optical sheet is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet is warped or crying after mounting and fixing the optical sheet to the liquid crystal display device. There is an effect of maintaining the light efficiency of the backlight unit by preventing the.

FIG. 21 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 22 is an exemplary view of an edge type light source.

On the other hand, in another aspect the present invention can provide a liquid crystal display device using the optical sheet described above.

As shown in FIG. 21, the LCD may include a light source 840 that emits light. In addition, the optical sheet 833 may be disposed on the light source 840 and have a maximum surface roughness of at least one side of both sides of 0.1 to 5 μm. In addition, the liquid crystal panel 820 may display an image by using light emitted from the light source 840.

The optical sheet 833 described above may have the same shape as described with reference to FIGS. 1 to 20.

Here, when the maximum surface roughness of at least one side of both sides of the optical sheet 833 has a range of 0.1 to 5 μm, it is easy to mount on the liquid crystal display and there is no problem of crying of the optical sheet even after fixing. Here, when the maximum surface roughness exceeds 5 µm, the surface roughness on both sides of the molded part of the optical sheet 833 becomes large. In such a case, when the optical sheet 833 is mounted on the liquid crystal display, the mounting of the optical sheet 833 becomes difficult. Nevertheless, if the optical sheet 833 is fixed after being forcedly mounted on the liquid crystal display, the optical sheet may cry.

However, when the maximum surface roughness of at least one side of both sides of the optical sheet 833 is formed in the range of 0.1 to 5 μm as in the present invention, the optical sheet 833 is mounted and fixed to the liquid crystal display, and then the optical sheet 833 ) Prevents warping or crying, thereby maintaining the light efficiency of the backlight unit.

Here, the light source 840, for example, Cold Cathode Fluorescent Lamp (CCFL), Hot Cathode Fluorescent Lamp (HCFL), External Electrode Fluorescent Lamp (EEFL) And a light emitting diode (LED) may be selected, but is not limited thereto.

In addition, the light source 840 may select any one of an edge type in which the lamp is located on one side outside, a dual type in which the lamp is located on both sides, and a direct type in which a plurality of lamps are arranged in a straight line, but is not limited thereto. The light source 840 as described above may be connected to an inverter to receive power to emit light.

Here, the light source 840 shown in FIG. 10 shows a direct type as an example. Alternatively, referring to FIG. 11, an edge type light source 940 is shown. The edge type light source 940 as shown may include a lamp 941 and a light guide plate 942 for guiding light emitted from the lamp 941 on one side outside.

The liquid crystal display may include a liquid crystal panel 820 for displaying an image, and an upper case 810 and a lower case 870 in which the light source 840 is accommodated.

Here, the lower case 870 may receive the light source 840. The liquid crystal panel 820 may be positioned at a predetermined interval on the light source 840. The liquid crystal panel 820 and the light source 840 may be fixed and protected by the upper case 810 fastened to the lower case 870.

An opening for exposing an image display area of the liquid crystal panel 820 may be provided on an upper surface of the upper case 810. In addition, a mold frame (not shown) may be further included on the periphery of the plurality of optical film layers 830 positioned between the liquid crystal panel 820 and the light source 840.

The liquid crystal panel 820 may have a structure in which an upper plate 822 having a color filter and a lower plate 821 having a thin film transistor are bonded to each other with a liquid crystal interposed therebetween. In the liquid crystal panel 820, subpixels driven independently by a thin film transistor are arranged in a matrix form, and a difference between a common voltage supplied to each common pixel and a data signal supplied to the pixel electrode through the thin film transistor is provided. The image can be displayed by controlling the liquid crystal array in accordance with the voltage to adjust the light transmittance.

In addition, the driving unit 825 may be connected to the lower plate 821 of the liquid crystal panel 820. The driver 825 is equipped with a driving chip 827 for driving the data line and the gate line of the liquid crystal panel 820, respectively, a plurality of film circuits 826 having one side connected to the lower plate 821, and a plurality of films. The printed circuit board 828 may be connected to the other side of the circuit 826.

The film circuit 826 on which the driving chip 827 is mounted shows a Chip On Film (COF) or Tape Carrier Package (TCP) method. Alternatively, the driving chip 827 may be directly mounted on the lower plate 821 in a chip on glass (COG) manner, or may be formed and embedded on the lower plate 821 in the thin film transistor forming process.

Here, the plurality of optical film layers 830 positioned between the liquid crystal panel 820 and the light source 840 may have a diffusion plate 831, a diffusion sheet 832, and a protective sheet 834 in addition to the optical sheet 833 described above. And the like may be further included.

The liquid crystal panel 820 described above may display an image on each pixel according to a scan signal supplied through the gate lines and a data voltage supplied through the data lines.

The scan signal may be a pulse signal in which a gate high voltage and a gate low voltage are alternated. The thin film transistor included in the pixel may be turned on when the gate high voltage is supplied from the gate lines to supply the data voltage applied from the data lines to the liquid crystal cell.

The liquid crystal cell may be formed between the pixel electrode supplied with the data voltage from the data lines and the common electrode applied with the common voltage.

Accordingly, when the thin film transistor of each pixel is turned on and the data voltage is applied to the pixel electrode, the liquid crystal display may display an image while charging the difference voltage between the data voltage and the common voltage in the liquid crystal cell.

On the contrary, when the gate low voltage is supplied from the gate lines, the thin film transistor is turned off and the data voltage charged in the liquid crystal cell can be maintained by the storage capacitor for one frame period. As such, the liquid crystal panel 820 may repeat different operations according to scan signals supplied through the gate lines.

Each embodiment of the present invention maintains the light efficiency of the backlight unit by preventing surface distortion or crying after mounting and fixing the optical sheet to a liquid crystal display device by placing a surface roughness on at least one side of both sides of the optical sheet. It is effective. In addition, by preventing the above problems, there is an effect of solving the problem of deterioration of the display quality of the liquid crystal display device and increasing the reliability of the product.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

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

FIG. 2 is an enlarged view of region X1 of FIG. 1;

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

4 is an enlarged view of region X2 of FIG. 3;

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

FIG. 6 is an enlarged view of region X3 of FIG. 5;

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

FIG. 8 is an enlarged view of region X4 of FIG. 7;

9 to 16 show various examples of protrusions.

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

FIG. 18 is an enlarged view of region X5 of FIG. 17;

19 is a sectional view of an optical sheet according to a fifth embodiment of the present invention.

20 is an enlarged view of area X6 of FIG. 19;

21 is an exploded perspective view of a liquid crystal display according to an embodiment of the present invention.

22 is an illustration of an edge type light source.

<Explanation of symbols on main parts of the drawings>

110, 210: reflective polarizing film layer 140, 240: first diffusion layer

250: second diffusion layer 145, 245: first diffusion particle

255: second diffusion particles 310, 410, 510: base film layer

Claims (15)

Reflective polarizing film layer; And Including a first diffusion layer located on one surface of the reflective polarizing film layer, Optical sheet, characterized in that the maximum surface roughness of at least one side of both sides of the reflective polarizing film layer is 0.1 ~ 5㎛. The method of claim 1, An optical sheet comprising a second diffusion layer located on the other surface of the reflective polarizing film layer. The method of claim 1, The maximum surface roughness of at least one side of both sides of the first diffusion layer is an optical sheet, characterized in that 0.1 to 5㎛. The method of claim 2, Optical sheet, characterized in that the maximum surface roughness of at least one side of both sides of the second diffusion layer is 0.1 ~ 5㎛. The method of claim 1, The thickness of the reflective polarizing film layer, Optical sheet, characterized in that 100 ~ 250 ㎛. The method of claim 1, The reflective polarizing film layer, An optical sheet comprising a plurality of layers having different refractive indices. The method of claim 2, The first diffusion layer and the second diffusion layer, An optical sheet attached to the reflective polarization film layer by an adhesive. A base film layer; Including a plurality of protrusions located on one surface of the base film layer, Optical sheet, characterized in that the maximum surface roughness of at least one side of both sides of the base film layer is 0.1 ~ 5㎛. The method of claim 8, The base film layer is an optical sheet including a protective layer located on the other surface. The method of claim 9, Optical sheet, characterized in that the maximum surface roughness of at least one side of both sides of the protective layer is 0.1 ~ 5㎛. The method of claim 8, The protrusion, An optical sheet comprising a prism, a lenticular lens and a micro lens. The method of claim 11, The prism is, A prism that contains a plurality of mountains and valleys, The height of the peak is characterized in that the optical sheet is variable along the longitudinal direction of the prism. The method of claim 11, The prism is, A prism that contains a plurality of mountains and valleys, The height of the mountain is an optical sheet, characterized in that the oscillating left and right. The method of claim 8, The plurality of protrusions, An optical sheet comprising a plurality of beads. Light source; An optical sheet positioned on the light source; And Including a liquid crystal panel positioned on the optical sheet, The optical sheet has a maximum surface roughness of at least one side of at least one side of both sides, characterized in that the liquid crystal display device.

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