Abstract:
An optical filter including: a base film; and a function incorporation layer on the base film and for shielding electromagnetic interference and absorbing external light, the function incorporation layer having a cross mesh pattern, wherein the cross mesh pattern includes a plurality of pattern lines, and wherein at least a part of the cross mesh pattern protrudes from a surface of the function incorporation layer facing toward the reflection prevention layer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/141,594, filed Dec. 30, 2008, the entire content of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     An aspect of the present invention relates to an optical filter and a flat display panel having the optical filter. 
     2. Description of the Related Art 
     As demand for large screen display panels increases among consumers, flat display panels have been widely developed. The flat display panels include liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), organic light emitting displays (OLEDs), and vacuum fluorescent displays (VFDs). 
     An optical filter is typically installed on the front surface of a flat display panel. The optical filter is used to protect the display panel from external shock or scratches, prevent reflection of external light, correct colors, shield EMI, enhance bright room contrast, and control other optical characteristics of the display panel. To perform these functions, the optical filter includes multiple function layers, which each include a film and an individual function layer formed on the film. Thus, manufacturing costs increase, and it is difficult to make flat display panel thinner. 
     SUMMARY OF THE INVENTION 
     An aspect of an embodiment of the present invention is directed toward an optical filter in which function layers for enhancing contrast and shielding electromagnetic interference (EMI) are incorporated, and a flat display panel having the optical filter. 
     An embodiment of the invention provides an optical filter including: a base film; and a function incorporation layer on the base film and for shielding electromagnetic interference and absorbing external light, the function incorporation layer having a cross mesh pattern, wherein the cross mesh pattern includes a plurality of pattern lines, and wherein at least a part of the cross mesh pattern protrudes from a surface of the function incorporation layer. 
     The function incorporation layer may include a base member on the base film, and the cross mesh pattern having at least a part thereof embedded in the base member. 
     The base member may have an inner wall defining a groove in the base member, and wherein each of the pattern lines may include: a first conductive layer including an inner portion on the inner wall of the groove and an outer portion; and a second conductive layer being on the inner portion and having a first portion inside the groove and a second portion protruding from a surface of the function incorporation layer; and the outer portion of the first conductive layer being on the second conductive layer. 
     The first conductive layer may have a higher external light absorption rate than that of the second conductive layer. 
     The second conductive layer may have a higher electric conductivity than that of the first conductive layer. 
     Each of the pattern lines may include: a first conductive layer; and a second conductive layer at least partially within the first conductor layer. 
     The optical filter may further include a reflection prevention layer, wherein the reflection prevention layer is coated on the function incorporation layer, exposed to light and developed to expose at least one edge portion. 
     The optical filter may further include an other base film on the function incorporation layer and a reflection prevention layer on the other base film, wherein the reflection prevention layer is on the other base film, and the reflection prevention layer and the other base film have a smaller size than the function incorporation layer for exposing at least one edge portion of the cross mesh pattern to ground the cross mesh pattern. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and extending in a substantially horizontal direction on a display panel; and a plurality of second pattern lines parallel to each other and extending in a substantially vertical direction on the display panel, the plurality of second pattern lines crossing the plurality of first pattern lines. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and extending in a first direction on a display panel; and a plurality of second pattern lines parallel to each other and extending in a second direction on the display panel, and wherein at least one of the first direction or the second direction is inclined with respect to a vertical or horizontal imaginary line on the display panel, the plurality of second pattern lines crossing the plurality of first pattern lines. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and separated by a first interval, each of the plurality of first pattern lines extending in a first direction and having a first width and a first height; and a plurality of second pattern lines parallel to each other and separated by a second interval, each of the plurality of second pattern lines extending in a second direction crossing the first direction and having a second width and a second height, wherein when the first width is substantially identical to the second width, the second height is smaller than the first height, and the second interval is larger than the first interval. 
     Another embodiment of the present invention provides a display device including: a display panel; a base film on the display panel; a function incorporation layer on the base film and for shielding electromagnetic interference and absorbing external light, the function incorporation layer having a cross mesh pattern, wherein the cross mesh pattern includes a plurality of pattern lines, and wherein at least a part of the cross mesh pattern protrudes from a surface of the function incorporation layer facing toward the reflection prevention layer. 
     The function incorporation layer may include a base member on the base film, and the cross mesh pattern having at least a part thereof embedded in the base member. 
     The base member may have an inner wall defining a groove in the base member, and wherein each of the pattern lines may include: a first conductive layer including an inner portion on the inner wall of the groove and an outer portion; and a second conductive layer being on the inner portion and having a first portion inside the groove and a second portion protruding from a surface of the function incorporation layer facing toward the reflection prevention layer; and the outer portion of the first conductive layer being on the second conductive layer. 
     Each of the pattern lines may include: a first conductive layer; and a second conductive layer at least partially within the first conductor layer. 
     The first conductive layer may have a higher external light absorption rate than that of the second conductive layer. 
     The second conductive layer may have a higher electric conductivity than that of the first conductive layer. 
     The display device may further include a reflection prevention layer, wherein the reflection prevention layer is coated on the function incorporation layer, exposed to light and developed to expose at least one edge portion. 
     The display device may further include an other base film on the function incorporation layer and a reflection prevention layer on the other base film, wherein the reflection prevention layer is on the other base film, and the reflection prevention layer and the other base layer film have a smaller size than the function incorporation layer for exposing at least one edge portion of the cross mesh pattern to ground the cross mesh pattern. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and extending in a substantially horizontal direction on a display panel; and a plurality of second pattern lines parallel to each other and extending in a substantially vertical direction on the display panel, the plurality of second pattern lines crossing the plurality of first pattern lines. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and extending in a first direction on a display panel; and a plurality of second pattern lines parallel to each other and extending in a second direction on the display panel, and wherein at least one of the first direction or the second direction is inclined with respect to a vertical or horizontal imaginary line on the display panel, the plurality of second pattern lines crossing the plurality of first pattern lines. 
     The pattern lines may include: a plurality of first pattern lines parallel to each other and separated by a first interval, each of the plurality of first pattern lines extending in a first direction and having a first width and a first height; and a plurality of second pattern lines parallel to each other and separated by a second interval, each of the plurality of second pattern lines extending in a second direction crossing the first direction and having a second width and a second height, wherein when the first width is substantially identical to the second width, the second height is smaller than the first height, and the second interval is larger than the first interval. 
     The display device may further include a color correction adhesive for attaching the base film to the display panel and for performing a color correction. 
     The display device may further include: a color correction layer on a surface of the base film facing the display panel; and a transparent adhesive between the color correction layer and the display panel. 
     The display device may further include a reflection prevention layer and another base film between the reflection prevention layer and the function incorporation layer, each of the reflection prevention layer and the another base film having a size for exposing the at least one edge portion of the cross mesh pattern to ground the mesh pattern. 
     Another embodiment of the present invention provides a display device including: a display panel; a base film on the display panel; a function incorporation layer on the base film and for shielding electromagnetic interference and absorbing external light, the function incorporation layer having a cross mesh pattern; a reflection prevention layer on the function incorporation layer and having a size for exposing at least one edge portion of the cross mesh pattern to ground the cross mesh pattern, wherein at least a part of the cross mesh pattern protrudes from a surface of the function incorporation layer facing toward the reflection prevention layer, wherein the cross mesh pattern includes: plurality of first pattern lines parallel to each other and separated by a first interval, each of the plurality of first pattern lines extending in a first direction and having a first width and a first height; and a plurality of second pattern lines parallel to each other and separated by a second interval, each of the plurality of second pattern lines extending in a second direction crossing the first direction and having a second width and a second height, wherein when the first width is set to be substantially identical to the second width, the second height is smaller than the first height, and the second interval is larger than the first interval, and wherein each of the first and second pattern lines includes: a first conductive layer; and a second conductive layer at least partially within the first conductor layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention. 
         FIG. 1  is a plan schematic view of an optical filter according to an embodiment of the present invention; 
         FIG. 2  is a cross-sectional schematic view taken along line II-II of  FIG. 1 ; 
         FIGS. 3A-3D  are cross-section schematic views showing the sequence of a method for forming a function incorporation layer for enhancing contrast and shielding EMI shown in  FIG. 2 ; 
         FIG. 4  is an enlarged perspective schematic view of a portion A of  FIG. 1 ; 
         FIG. 5  illustrates the blocking of incident light in the function incorporation layer for enhancing contrast and shielding EMI; 
         FIG. 6  is a plan schematic view of an optical filter according to another embodiment of the present invention; 
         FIG. 7  is an enlarged perspective schematic view of a portion B of  FIG. 6 ; 
         FIG. 8  is a plan schematic view of a modified example of the optical filter of  FIG. 1 ; 
         FIG. 9  is a plan schematic view of another modified example of the optical filter of  FIG. 1 ; 
         FIG. 10  is a plan schematic view of another modified example of the optical filter of  FIG. 1 ; 
         FIGS. 11A-11D  are cross-sectional schematic views illustrating a method for manufacturing an optical filter according to an embodiment of the present invention; 
         FIG. 12  is a cross-sectional schematic view of a flat display panel having an optical filter according to an embodiment of the present invention; 
         FIG. 13  is a cross-sectional schematic view of a flat display panel having an optical filter according to another embodiment of the present invention; and 
         FIG. 14  is a cross-sectional schematic view of a flat display panel having an optical filter according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, only certain exemplary embodiments of the present invention are shown and described, by way of illustration. As those skilled in the art would recognize, the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Also, in the context of the present application, when an element is referred to as being “on” another element, it can be directly on the another element or be indirectly on the another element with one or more intervening elements interposed therebetween. Like reference numerals designate like elements throughout the specification. 
       FIG. 1  is a plan schematic view of an optical filter  100  according to an embodiment of the present invention.  FIG. 2  is a cross-sectional schematic view taken along line II-II of  FIG. 1 . Referring to  FIGS. 1 and 2 , the optical filter  100  includes a first base film  110 , a function incorporation layer  120 , and a reflection prevention layer  130 . 
     The first base film  110  may be formed of a material capable of transmitting a visible ray. The first base film  110  enables the optical filter  100  to be directly attached to the front surface of a display panel. The first base film  110  may be formed of a material including polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), polyethyeleneterepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide (PI), polycarbonate (PC), triacetate cellulose (TAC), and/or cellulose acetate propinonate (CAP). However, the material of the first base film  110  is not limited thereto and any material that is flexible and capable of transmitting a visible ray may be employed. 
     The first base film  110  may have a set (or predetermined) color. Accordingly, the transmissivity of a visible ray of the optical filter  100  may be adjusted, a viewing experience may be improved, a color purity may be improved, or the color may be corrected. The function incorporation layer  120  is formed on the first base film  110 . In the present embodiment, the function incorporation layer  120  is formed to both perform a bright room contrast enhancement function and the EMI shielding function. That is, the function incorporation layer  120  is a layer in which a contrast enhanced layer and an EMI shield layer are incorporated. The EMI shielding layer shields EMI that is generated by the display panel and harmful to a human body. The contrast enhanced layer enhances bright room contrast by absorbing external light. In the function incorporation layer  120 , a mesh pattern  122  is partially buried in a base member  121 . The mesh pattern  122  is formed to both perform the bright room contrast enhancement function and the EMI shielding function, which will be described in more detail later. 
     The mesh pattern  122   a  extends horizontally and parallel to one another, and the mesh pattern  122   b  extends vertically and parallel to one another, as shown in  FIG. 1 . The mesh pattern extending horizontally is referred to as a first mesh pattern  122   a , while the mesh pattern extending vertically is referred to as a second mesh pattern  122   b . The mesh patterns  122   a  and  122   b  protrude from the upper surface of the base member  121  in the function incorporation layer  120 . Thus, a grounding function to a ground member of the display panel may be improved. 
     In the present embodiment, the reflection prevention layer  130  may include a reflection reduction layer and a surface hardness enforcement layer. The reflection reduction layer may be formed of either an anti-reflection (AR) layer or an anti-glare (AG) layer. Alternatively, the reflection reduction layer may be formed of an AR/AG combined layer. Thus, the reflection reduction layer disperses the external light at a surface thereof and reduces (or prevents) the reflection of the surrounding environment by the surface of the optical filter  100 . 
     In another embodiment, the reflection prevention layer  130  may be formed of a single layer of a surface hardness enforcement layer. The surface hardness reinforcement layer is a hard coating layer including a hard coating material. Thus, the reflection prevention layer  130  may protect against scratches on the optical filter  100  generated by external matter(s). 
     In the present embodiment, the reflection prevention layer  130  is formed on the function incorporation layer  120 . The reflection prevention layer  130  may be formed by coating, for example, a roll wet coating. The reflection prevention layer  130  is formed away from an edge portion of the function incorporation layer  120  such that the mesh pattern  122  may be exposed above the base member  121 . As a result, ground to the ground member is possible. The method for forming the function incorporation layer  120  and the reflection prevention layer  130  on and above the first base film  110  is described in more detail below. The characteristics, materials, and formation method of the reflection prevention layer  130  are not limited to the above-described embodiment. 
     Referring to  FIGS. 3A-3D , in a method of forming the function incorporation layer  120  for enhancing contrast and shielding EMI of  FIG. 2 , the base member  121  having a groove  121   a  is prepared. The base member  121  with the groove  121   a  may be made by coating a base material forming the base member  121  on a mold designed according to a set (or predetermined) mesh pattern  122  and curing, for example, UV curing, the coated base member  121 . Alternatively, the groove  121   a  may be formed in a flat base member  121  in a laser etch method performed according to the set (or predetermined) mesh pattern  122 . 
     Next, a first conductive layer  122   aa  is formed on the groove  121   a  of the base member  121 . The first conductive layer  122   aa  is not necessarily black in color and may be in a dark color that is dark enough to effectively absorb external light. For example, the first conductive layer  122   aa  may be grey. Thus, the mesh pattern  122  of the function incorporation layer  120  enhances bright room contrast. The first conductive layer  122   aa  may have a low electrical conductivity. The first conductive layer  122   aa  may be formed of, for example, a material including chromium (Cr) or nickel (Ni). 
     Next, a second conductive layer  122   ab  is formed on the first conductive layer  122   aa . The second conductive layer  122   ab  is to supplement the low conductivity of the first conductive layer  122   aa  so that the second conductive layer  122   ab  may be formed by plating a metal exhibiting an electrical resistance lower than that of the first conductive layer  122   aa . The second conductive layer  122   ab  may be formed of, for example, a material including aluminum (Al), silver (Ag), or copper (Cu). Thus, the electric conductivity of the second conductive layer  122   ab  is greater than that of the first conductive layer  122   aa . As a result, the mesh pattern  122  of the function incorporation layer  120  may shield EMI with the same effect as that of the conventional EMI shield layer. 
     Finally, a third conductive layer  122   ac  is formed on the second conductive layer  122   ab . Although the third conductive layer  122   ac  may be formed of the same (or substantially the same) material as and in the same (or substantially the same) method as that of the first conductive layer  122   aa , the present invention is not limited thereto. In one embodiment, the third conductive layer  122   ac  has a color that can absorb the external light better than the second conductive layer  122   ab.    
     As described above, as the second conductive layer  122   ab  exhibiting a higher electrical conductivity but a lower external light absorption characteristic is surrounded by the first conductive layer  122   aa  and the third conductive layer  122   ac  that are darker than the second conductive layer  122   ab , the bright room contrast of the function incorporation layer  120  may be enhanced. Also, since the second conductive layer  122   ab  exhibiting a higher electrical conductivity exists in the mesh pattern  122  of the function incorporation layer  120 , the EMI shield function may also be enhanced. In an embodiment in which the process of  FIG. 3D  is omitted, the second conductive layer may be formed by utilizing a metal having a dark color, if possible, only when the electrical resistance of the metal is lower than that of the first conductive layer. 
       FIG. 4  is an enlarged perspective view of a portion A of  FIG. 1 . Referring to  FIG. 4 , the mesh pattern  122  of the function incorporation layer  120  includes the first mesh pattern  122   a  extending horizontally and parallel to each other and the second mesh pattern  122   b  extending vertically and parallel to each other. Since the first mesh pattern  122   a  is arranged to extend horizontally, the first mesh pattern  122   a  mainly absorbs external light incident at an angle from the upper or lower side of the display panel. Also, since the second mesh pattern  122   b  is arranged to extend vertically, the second mesh pattern  122   b  mainly absorbs external light incident at an angle from the left or right side of the display panel. A horizontal viewing angle is generally more noticeable (important) than a vertical viewing angle in a flat display panel. Also, in general, it is more important to absorb the external light that is vertically incident. Here, the mesh pattern  122  limits the viewing angle, but absorbs external light. 
     Thus, in the horizontal direction, since the absorption of external light is less important, but obtaining a wide viewing angle is more important, to decrease the effect of the second mesh pattern  122   b  absorbing the external light that is horizontally incident and assuming that the width of the first mesh pattern  122   a  is the same as that of the second mesh pattern  122   b , the height of the second mesh pattern  122   b  is set to be lower than that of the first mesh pattern  122   a . Also, the interval between each part of the second mesh pattern  122   b  is set to be greater than that between each part of the first mesh pattern  122   a . In contrast, in the vertical direction, since obtaining a wide viewing angle is less important, but the absorption of external light is more important, to increase the effect of the first mesh pattern  122   a  absorbing external light that is vertically incident and assuming that the width of the first mesh pattern  122   a  is the same (or substantially the same) as that of the second mesh pattern  122   b , the height of the first mesh pattern  122   a  is set to be greater than that of the second mesh pattern  122   b . Also, the interval between each part of the first mesh pattern  122   a  is set to be less than that between each part of the second mesh pattern  122   b.    
     Thus, the optical filter  100  according to the present embodiment is configured such that the absorption of external light in the vertical direction in which incident external light is relatively large may be increased (or maximized) and the obtaining of a viewing angle in the horizontal direction may be increased (or maximized). The mesh pattern  122  of the function incorporation layer  120  of the optical filter  100  is formed both in the vertical and horizontal directions and has a sufficiently high electric conductivity so that the EMI shield function may be sufficiently performed. 
     In the embodiment of  FIG. 4 , the height of the second mesh pattern  122   b  is lower than that of the first mesh pattern  122   a , but the present invention is not limited thereto. For example, the purpose of an aspect of the present invention may be achieved even when the height of the second mesh pattern  122   b  is not lower than that of the first mesh pattern  122   a , which will be described below with reference to  FIG. 5 . 
       FIG. 5  illustrates the blocking of incident light in the function incorporation layer  120  for enhancing contrast and shielding EMI. The size of a mesh pattern  122   a ′ indicated by a two-dot chain line and the interval between the mesh patterns are, respectively, ½ of the size of the mesh pattern  122   a  indicated by a solid line and ½ of the interval between the mesh patterns  122   a .  FIG. 5  shows that the same external light absorption effect may be obtained in both of the embodiment of the optical filter  10  having the mesh pattern  122   a  indicated by a solid line and the embodiment of the optical filter  10  having the mesh pattern  122   a ′ indicated by a two-dot chain line. 
     In more detail, assuming that external light is incident at a set (or predetermined) inclination with respect to the surface of the optical filter  100 , external light incident (indicated by the arrows) at the inclination shown in  FIG. 5  is all absorbed by the mesh pattern  122   a  indicated by the solid line. Likewise, external light incident (indicated by the arrows) at the same inclination is all absorbed by the mesh pattern  122   a ′ indicated by the two-dot chain line. That is, in an ideal state, even when the size (height) of the mesh pattern  122  decreases, by decreasing the interval between each of the mesh pattern  122   a  at a similar or the same rate, the capability of absorbing external light may be about the same (or maintained unchanged). 
       FIGS. 6 and 7  schematically illustrate an optical filter  200  according to an embodiment of an aspect of the present invention in which the overall size of the first mesh pattern  222   a  extending horizontally and parallel to each other using the above principle is decreased by half and the interval between each of the first mesh patterns  222   a  is also decreased by half. Referring to  FIGS. 6 and 7 , while the size of a second mesh pattern  222   b  and the interval between each of the second mesh pattern  222   b  are maintained unchanged, the size of a first mesh pattern  222   a  and the interval between each of the first mesh pattern  222   a  are decreased by half. Accordingly, unlike the embodiment shown in  FIG. 4 , in the embodiment shown in  FIG. 7 , the height of the second mesh pattern  222   b  is not less than that of the first mesh pattern  222   a . Thus, by adjusting the interval between each of the second mesh pattern  222   b  or the interval between each of the first mesh pattern  222   a , the technical object of an aspect of the present invention may be achieved without forming the second mesh pattern  222   b  to be lower than the first mesh pattern  222   a.    
       FIG. 8  is a plan view of an optical filter  300  according to a modified example of the optical filter of  FIG. 1 . The optical filter  300  of the present embodiment is different from the optical filter  100  of  FIG. 1  in that a second mesh pattern  322   b  is inclined at a set (or predetermined) angle of θ 1 , for example, inclined at an angle θ 1  between 0° and 45°, with respect to a vertical imaginary line. This modified example is designed to reduce a Moiré phenomenon that might otherwise occur due to interference between the mesh pattern  122  of the function incorporation layer  120  and the pattern of the display panel  10 , that is, all patterns that may be generated from the display panel  10  including an electrodes pattern and a barrier ribs pattern. In particular, since a first mesh pattern  322   a  extending horizontally greatly contributes to the absorption of the external light incident vertically, the first mesh pattern  322   a  is maintained parallel to a horizontal imaginary line. The present embodiment is particularly desired for this in mind. However, the present invention is not limited thereto. 
     As another modified example of the embodiment of  FIG. 1 , a mesh pattern  422  of an optical filer  400  may be arranged as shown in  FIG. 9 . Referring to  FIG. 9 , in the optical filter  400  of the present embodiment, a second mesh pattern  422   b  is inclined at a set (or predetermined) angle of θ 1 , for example, inclined at an angle θ 1  between 0° and 45°, with respect to a vertical imaginary line, and a first mesh pattern  422   a  is inclined at a set (or predetermined) angle of θ 2 , for example, inclined at an angle θ 2  between 0° and 45°, with respect to a horizontal imaginary line, which is a difference from the embodiment of  FIG. 1 . The reason for this is the same (or substantially the same) as that described above for the embodiment of  FIG. 8 . 
     As another modified example of the embodiment of  FIG. 1 , a mesh pattern  522  of an optical filer  500  may be arranged as shown in  FIG. 10 . Referring to  FIG. 10 , in the optical filter  500  of the present embodiment, a first mesh pattern  522   a  is inclined at a set (or predetermined) angle of θ 2 , for example, inclined at an angle θ 2  between 0° and 45°, with respect to a horizontal imaginary line, which is a difference from the optical filter  100  of  FIG. 1 . The reason for this is the same (or substantially the same) as that described above for the embodiment of  FIG. 8 . 
       FIGS. 11A-11D  are cross-sectional schematic views illustrating a method for manufacturing an optical filter  100  according to an embodiment of an aspect of the present invention. First, the base member  121  with a groove  121   a  is arranged on the first base film  110 . For example, the base member  121  may be formed by transferring a shape of a mold having a set (or predetermined) mesh pattern  122  to a base material coated on the first base film  110 . Alternatively, after the base member  121  that is flat is formed on the first base film  110 , the groove  122   a  may be formed in the upper surface of the base member  121 , for example, by a laser etch method. 
     The function incorporation layer  120  is completed by forming the mesh pattern  122  on the base member  121  shown in  FIG. 11B . The function incorporation layer  120  may be formed in the method described with reference to  FIGS. 3A-3D . 
     A material forming the reflection prevention layer  130  is coated on the function incorporation layer  120  shown in  FIG. 11C . For the reflection prevention layer  130 , the above descriptions will be referred to. Both side edge portions of the function incorporation layer  120  are separated from the reflection prevention layer  130  (or side edge portions of the reflection prevention layer  130  are removed from the function incorporation layer  120 ) to externally expose the mesh pattern  122  formed at both side edge portions of the function incorporation layer  120 . The separation may be performed by a physical and/or chemical method. For example, chemical etching and/or an optical method by utilizing a laser may be used for the separation. Also, a physical separation in a method of attaching an adhesive tape and detaching the same may be used. 
       FIG. 11D  illustrates that both side edge portions of the function incorporation layer  120  are separated from the reflection prevention layer  130 , but the scope of the present invention is not limited thereto. For example, only one side edge portion, both side edge portions, or all four side edge portions of the function incorporation layer  120  may be separated from the reflection prevention layer  130 . 
       FIG. 12  is a cross-sectional schematic view of the flat display panel  1  having the optical filter  100  according to an embodiment of an aspect of the present invention. Referring to  FIG. 12 , the flat display panel of the present embodiment is manufactured by attaching the first base film  110  of the optical filter  100  manufactured in the method shown in  FIGS. 11A-11D  to the display panel  10  using a color correction adhesive  20 . Here, the color adhesive layer  20  may perform both color correction and adhesion function. By incorporating the color correction layer and the adhesive layer as a single layer, manufacturing costs may be reduced and the manufacturing process may be simplified. 
     Thus, as the function incorporation layer  120  and the reflection prevention layer  130  both are included in the first base film  110 , manufacturing costs are reduced and a manufacturing process is simplified so that the flat display panel  1  may be made thinner. Also, not only the EMI shield function but also the bright room contrast enhancement function may be performed by the function incorporation layer  120  that is a single layer. 
       FIG. 13  is a cross-sectional view of a flat display panel  2  having an optical filter according to another embodiment of an aspect of the present invention. The present embodiment is different from the embodiment of  FIG. 12  in that a color correction layer  22  and an adhesive layer  21  are separately formed. In the optical filters according to the above-described embodiments, both of the function incorporation layer  120  and the reflection prevention layer  130  are formed on the base film  110  that is a single layer. However, the present invention is not limited thereto. 
       FIG. 14  is a cross-sectional view of a flat display panel  3  having an optical filter according to another embodiment of an aspect of the present invention. Referring to  FIG. 14 , a reflection prevention layer  132  may be formed on a separate base film  131 , and the reflection prevention films  131  and  132  may be formed on the function incorporation layer  120 . The sizes of the reflection prevention films  131  and  132  are determined such that the mesh pattern  122  at least one side edge portion of the function incorporation layer  120  may be exposed. Thus, a separate separation process is not needed. 
     The flat display panels  1 ,  2 , and  3  according to the embodiments of an aspect of the present invention may be PDPs, LCDs, FEDs, OLEDs, or VFDs. Also, the optical filters  100 ,  200 ,  300 ,  400 , and  500  according to the embodiments of an aspect of the present invention may be used for PDPs, LCDs, FEDs, OLEDs, or VFDs. 
     As described above, the optical filters according to embodiments of an aspect of the present invention and the flat display panels according to embodiments of an aspect of the present invention may include both of the function incorporation layer and the reflection prevention layer on a single base film. Thus, manufacturing costs are reduced, a manufacturing process is simplified, and a flat display panel may be made thinner. Also, not only the EMI shielding function but also the bright room contrast enhancement function may be performed by a single function incorporation layer. 
     An aspect of the present invention may be utilized in the fields of manufacturing and using an optical filter and a flat display panel having the optical filter. 
     An aspect of an embodiment of the invention provides an optical filter including a base film, a function incorporation layer formed on a first surface of the base film, and a reflection prevention layer formed on the function incorporation layer, wherein the function incorporation layer shields electromagnetic interference and absorbs external light. Both of the function incorporation layer and the reflection prevention layer are provided on a single base film. Thus, manufacturing costs may be reduced, a manufacturing process may be simplified, and a flat display panel may be made thinner. 
     The function incorporation layer has a mesh pattern having cross patterns in it and at least a part of the mesh pattern may protrude from an upper surface of the function incorporation layer. The function incorporation layer may include a base member formed on a first surface of the base film and a mesh pattern having at least a part thereof buried in the base member and having cross patterns in it. Thus, a ground capability with a ground member of a display panel is guaranteed. 
     The reflection prevention layer may be coated on the function incorporation layer. In this case, a separate base film for the reflection prevention layer is not needed. Since all function layers are formed on a single base film, manufacturing costs may be reduced. However, an edge portion corresponding to the reflection prevention layer can be separated so that the mesh pattern at least one side edge portion of the display panel may be externally exposed. 
     Alternatively, a reflection prevention film on which the reflection prevention layer is formed may be coupled to the function incorporation layer after the reflection prevention layer is formed on the separate base film. In this case, the size of the reflection prevention film is determined so that the mesh pattern at least one side edge portion of the function incorporation layer may be exposed. Thus, a separate separation process is not needed. 
     The mesh pattern may include a first mesh pattern extending in an approximately horizontal direction on the display panel and parallel to each other and a second mesh pattern extending in an approximately vertical direction on the display panel and parallel to each other. The first and second mesh patterns form cross patterns. 
     Alternatively, the second mesh pattern may be formed to be inclined with respect to a vertical imaginary line. Then, a Moiré phenomenon generated with the pattern, for example, a lattice shaped pattern, of the display panel may be prevented. Additionally, the first mesh pattern may be formed to be inclined with respect to a horizontal imaginary line. Alternatively, only the first mesh pattern may be formed to be inclined with respect to the horizontal imaginary line. 
     Assuming that the width of the first mesh pattern and the width of the second pattern are identical or almost similar to each other, the height of the second mesh pattern is smaller than that of the first mesh pattern. Also, the interval between the second mesh patterns is larger than that between the first mesh patterns. Accordingly, the external light incident in the vertical direction that has a great effect on a bright room contrast is absorbed much by the first mesh patterns while the external light incident in the horizontal direction is relatively less absorbed by the second mesh patterns. Thus, a horizontal viewing angle may be sufficiently obtained while the bright room contrast is enhanced. 
     However, the height of the second mesh pattern does not necessarily have to be smaller than the height of the first mesh pattern. By reducing the size, including the width of the first mesh pattern and the interval between the first mesh patterns, at the same reduction rate, the height of the second mesh pattern may be maintained larger than or almost same as the height of the first mesh pattern while the performance of absorbing the external light incident in the vertical direction is maintained. 
     Each of the first and second mesh patterns may be formed of an external black conductive layer and an internal conductive layer. The external black conductive layer has a higher external light absorption rate than the inner conductive layer because the color of the external black conductive layer is darker than the inner conductive layer. Thus, the function incorporation layer may enhance the bright room contrast. In contrast, the inner conductive layer has a higher electrical conductivity than the external black conductive layer. Thus, the function incorporation layer may enhance an EMI shield function. 
     The mesh pattern may be formed by forming a black conductive layer on an inner wall of a groove of the base member forming the function incorporation layer, a conductive layer inside the groove to protrude from the upper surface of the function incorporation layer, and another black conductive layer on the conductive layer. 
     According to another aspect of the embodiment of the invention, there is provided a flat display panel including a display panel, a base film arranged on the front surface of the display panel, a function incorporation layer formed on a first surface of the base film, and a reflection prevention layer formed on the function incorporation layer, wherein the function incorporation layer shields electromagnetic interface and absorbs external light. Both of the function incorporation layer and the reflection prevention layer are provided on a single base film. Thus, manufacturing costs may be reduced, a manufacturing process may be simplified, and a flat display panel may be made thinner. 
     The base film may be attached to the flat display panel using a color correction adhesive. The color correction adhesive simultaneously performs a color correction function and an adhesive function. Since a color correction layer and an adhesive layer are incorporated, manufacturing costs may be reduced and a manufacturing process may be simplified. 
     Alternatively, the color correction layer may be arranged on a second surface of the base film and the color correction layer may be substantially attached to the first surface of the flat display panel using a transparent adhesive. 
     According to another aspect of an embodiment of the invention, there is provided a flat display panel including a display panel, a first base film arranged on the first surface of the display panel, a function incorporation layer formed on a first surface of the first base film, and a reflection prevention layer having a second base film formed on the function incorporation layer, wherein the function incorporation layer shields electromagnetic interface and absorbs external light. The reflection prevention layer is formed on a separate base film and the reflection prevention film is arranged on the function incorporation layer. The size of the reflection prevention film may be determined such that a mesh pattern at least one side edge portion of the function incorporation layer may be exposed. Thus, a separate separation process is not needed. 
     While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.