Patent Publication Number: US-2015082897-A1

Title: Touch sensor module

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2013-0113406, filed on Sep. 24, 2013, entitled “Touch Sensor Module”, which is hereby incorporated by reference in its entirety into this application. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a touch sensor module. 
     2. Description of the Related Art 
     With the development of computers using a digital technology, computer-aided devices have also been developed, and personal computers, portable transmitters and other personal information processors execute processing of texts and graphics using a variety of input devices such as a keyboard and a mouse. 
     With the rapid advancement of an information-oriented society, the use of computers has gradually been expanded; however, it is difficult to efficiently operate products using only a keyboard and a mouse which currently serve as input devices. Therefore, the necessity for a device, which has a simple configuration and less malfunction and is configured anyone to easily input information, has increased. 
     In addition, technologies for input devices have progressed toward techniques related to high reliability, durability, innovation, designing and processing, and the like, in addition to satisfying general functions. To this end, a touch sensor has been developed as input devices capable of inputting information such as texts and graphics. 
     The touch sensor is a device which is mounted on a display surface of a display such as an electronic organizer, a flat panel display device including a liquid crystal display (LCD) device, a plasma display panel (PDP), and an electroluminescence (El) element, and the like, and a cathode ray tube (CRT) to be used to allow a user to select desired information while viewing the display. 
     In addition, a type of the touch sensor may be classified into a resistive type, a capacitive type, an electro-magnetic type, a surface acoustic wave (SAW) type, and an infrared type. 
     These various types of touch sensors have been adapted for electronic products in consideration of a signal amplification problem, a resolution difference, a difficulty of designing and processing technology, optical characteristics, electrical characteristics, mechanical characteristics, anti-environment characteristics, input characteristics, durability, and economic efficiency. Currently, the resistive type touch sensor and the capacitive type touch sensor have been used in a wide range of fields. 
     As a specific example of a touch panel according to the prior art, there may be a touch sensor disclosed in Korean Patent Laid-Open Publication No. 10-2011-0107590. 
     Describing a structure of the touch sensor disclosed in the prior art in a specification of Korean Patent Laid-Opened Publication No. 10-2011-0107590, the touch sensor is configured to include a substrate, electrodes formed on the substrate, electrode wirings extending from the electrodes and gathered on one end of the substrate, and a controller connected to the electrode wirings through a flexible printed circuit board (FPCB) (hereinafter, referred to as ‘flexible cable’). 
     Here, the FPCB serves to transfer signals generated from the electrode to the controller through the electrode wirings. In this case, the FPCB is electrically connected to the electrode wirings by contacting the electrode wirings so as to transfer the signals. However, a poor contact between the FPCB and the electrode wiring frequently occurs due to an infiltration of moisture. As such, the poor contact frequently occurring may lead to a reduction in reliability of products. 
     PRIOR ART DOCUMENT 
     Patent Document 
     (Patent Document 1) KR10-2011-0107590 A 
     SUMMARY OF THE INVENTION 
     The present invention has been made in an effort to provide a touch sensor module capable of preventing a short-circuit and a poor contact between an electrode pad and a flexible cable from occurring due to moisture, by forming passivation layers at both ends of the electrode pad. 
     According to a preferred embodiment of the present invention, there is provided a touch sensor module, including: a flexible cable provided with a terminal part; an adhesive layer formed to transfer an electrical signal by being contacted on one surface of the terminal part; a base substrate including an electrode pad which is formed to correspond to the terminal part and formed to be contact on the other surface of the adhesive layer; and a first passivation layer coating one end of the electrode pad. 
     The adhesive layer may use an anisotropic conductive film (ACF) or an anisotropic conductive adhesive (ACA). 
     A surface of the first passivation layer and a surface of the electrode pad may be formed to have a step so as to increase a hardening rate of the adhesive layer. 
     The first passivation layer may be formed to be larger by 1 μm to 8 μm than the surface of the electrode pad to increase the hardening rate and prevent infiltration of moisture. 
     The touch sensor module may further include: a second passivation layer formed to be coated along an outer circumferential surface of the electrode pad and formed to be equal to a height of the first passivation layer. 
     The touch sensor module may further include: a second passivation layer formed to coat the other end of the electrode pad and formed along an outer circumferential surface of the base substrate. 
     The first and second passivation layers may be formed on surfaces of both ends of the electrode pad to have a step so as to increase the hardening rate and are formed to have the same height. 
     The first passivation layer and the second passivation layer may be formed to be larger by 1 μm to 8 μm than the surface of the electrode pad to increase the hardening rate and prevent infiltration of moisture. 
     According to another preferred embodiment of the present invention, there is provided a touch sensor module, including: a base substrate provided with an electrode pad; a first passivation layer coating one end of the electrode pad in a thickness direction thereof; an adhesive layer coupling the first passivation layer with the electrode pad; and a flexible cable formed to correspond to the electrode pad and be electrically connected thereto in an area other than the first passivation layer. 
     The adhesive layer may use an anisotropic conductive film (ACF) or an anisotropic conductive adhesive (ACA). 
     A surface of the first passivation layer and a surface of the electrode pad may be formed to have different steps so as to increase a hardening rate of the adhesive layer. 
     The first passivation layer may be formed to be larger by 1 μm to 8 μm than the surface of the electrode pad to increase the hardening rate and prevent infiltration of moisture. 
     According to another preferred embodiment of the present invention, there is provided a touch sensor module, including: a base substrate provided with an electrode pad; a first passivation layer coating one end of the electrode pad in a thickness direction thereof; a second passivation layer coating the other end of the electrode pad in a thickness direction thereof; an adhesive layer crossing the first and second passivation layers to be filled in the electrode pad and coupled therewith; and a flexible cable formed to correspond to the electrode pad and be electrically connected thereto in an area other than the first passivation layer and the second passivation layer. 
     The adhesive layer may use an anisotropic conductive film (ACF) or an anisotropic conductive adhesive (ACA). 
     The first and second passivation layers may be formed on surfaces of both ends of the electrode pad to have a step so as to increase the hardening rate and may be formed to have the same height. 
     The first passivation layer and the second passivation layer may be formed to be larger by 1 μm to 8 μm than the surface of the electrode pad to increase the hardening rate and prevent infiltration of moisture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a top coupling cross-sectional view of a touch sensor module according to a preferred embodiment of the present invention and a flexible cable (FPCB); 
         FIG. 2  is a bottom coupling cross-sectional view of the touch sensor module according to the preferred embodiment of the present invention and the FPCB; 
         FIG. 3  is a top/bottom partial view of a base substrate on which the touch sensor module according to the preferred embodiment of the present invention and the FPCB; 
         FIG. 4  is a cross-sectional view of a first modification example of the preferred embodiment of the present invention illustrated in  FIG. 1 ; 
         FIG. 5  is a partially enlarged view of an electrode pattern illustrated in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of a touch sensor module according to a second preferred embodiment of the present invention and the FPCB; and 
         FIG. 7  is a cross-sectional view of a second modification example of the preferred embodiment of the present invention illustrated in  FIG. 6 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The objects, features and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side” and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the related art would obscure the gist of the present invention, the description thereof will be omitted. 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. 
       FIG. 1  is a top coupling cross-sectional view of a touch sensor module according to a preferred embodiment of the present invention and a flexible cable (FPCB);  FIG. 2  is a bottom coupling cross-sectional view of the touch sensor module according to the preferred embodiment of the present invention and the FPCB;  FIG. 3  is a top/bottom partial view of a base substrate on which the touch sensor module according to the preferred embodiment of the present invention and the FPCB;  FIG. 4  is a cross-sectional view of a first modification example of the preferred embodiment of the present invention illustrated in  FIG. 1 ;  FIG. 5  is a partially enlarged view of an electrode pattern illustrated in  FIG. 4 ;  FIG. 6  is a cross-sectional view of a touch sensor module according to a second preferred embodiment of the present invention and the FPCB; and  FIG. 7  is a cross-sectional view of a second modification example of the preferred embodiment of the present invention illustrated in  FIG. 6 . 
     The term ‘touch’ used in the present specification means a direct contact to a contact receiving surface and is to be broadly construed as a meaning that an input device considerably approaches the contact receiving surface. 
     A touch sensor module  1  according to a preferred embodiment of the present invention includes a flexible cable  300  provided with a terminal part  320 , an adhesive layer  200  formed to transfer an electrical signal by being contacted on one surface of the terminal part  320 , a base substrate  110  including an electrode pad  140  which is formed to correspond to the terminal part  320  and formed to be contact on the other surface of the adhesive layer  200 , and a passivation layer  400  coating one end of the electrode pad  140 . 
     The preferred embodiment of the present invention is to more improve anti-environment characteristics in addition to moisture resistance of the touch sensor module  1  and is to minimize an infiltration of moisture, and the like, into the touch sensor module  1 . Therefore, the operation reliability of the touch sensor module  1  may be kept even under the high temperature and humidity environment, such that user convenience and a field of products to which the touch sensor module  1  is applied may be more diversified. 
     As a touch sensor  100  according to the preferred embodiment of the present invention, a resistive type touch sensor  100 , a capacitive type touch sensor  100 , or other various types of touch sensors  100  may be applied and a type and a kind of the touch sensor  100  are not particularly limited. However, in the touch sensor module  1  according to the preferred embodiment of the present invention, the capacitive type touch sensor  100  in which electrode patterns  120  and  130  are formed on both surfaces of the base substrate (transparent substrate)  110  will be described as one example. 
     Referring to  FIG. 1 , the base substrate  110  serves to provide a region in which the electrode patterns  120  and  130  and electrode wirings  150  and  160  are formed. In this configuration, the base substrate  110  is partitioned into an active region and a bezel region, in which the active region is a portion in which the electrode patterns  120  and  130  are formed to recognize the touch of the input device and is disposed at a center of the base substrate  110  and the bezel region is a portion in which the electrode wirings  150  and  160  extending from the electrode patterns  120  and  130  are formed and is disposed at an edge of the active region. In this case, the base substrate  110  needs to have a support force capable of supporting the electrode patterns  120  and  130  and the electrode wirings  150  and  160  and transparency to allow a user to recognize an image provided by an image display device (not illustrated). Considering the support force and the transparency, the base substrate  110  may be preferably made of polyethyleneterephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylenenaphthalate (PEN), polyethersulfone (PES), cyclic olefin copolymer (COC), triacetylcellulose (TAC) film, polyvinyl alcohol (PVA) film, polyimide (PI) film, polystyrene (PS), biaxially oriented polystyrene (BOPS; containing K resin), glass, tempered glass, or the like, but the material forming the base substrate  110  is not necessarily limited thereto. 
     Referring to  FIGS. 1 to 3 , the electrode patterns  120  and  130  serve to generate a signal when being touched by the input device so as to allow a controller to recognize touched coordinates and is formed on the base substrate  110 . According to the preferred embodiment of the present invention, an electrode pattern formed in an X-axis direction of the base substrate  110  is named as the first electrode pattern  120  and an electrode pattern formed in a Y-axis direction of the base substrate  110  is named as the second electrode pattern  130 . 
     The electrode patterns  120  and  130  may be formed by a plating process or a depositing process using a sputter. It is apparent to those skilled in the art that the electrode patterns  120  and  130  may use metal formed by exposing/developing a silver salt emulsion layer and may use various kinds of materials which may form a mesh pattern using a conductive metal. The electrode patterns  120  and  130  may be formed in all the patterns, such as a diamond pattern, a quadrangular pattern, a triangular pattern, and a circular pattern, which are known to those skilled in the art. 
     The electrode patterns  120  and  130  are formed on the base substrate  110  as a bar pattern orthogonal to a bar pattern in one direction. A mutual type touch sensor may perform the touch driving by forming the electrode patterns  120  and  130  on both surfaces of the base substrate  110 . Further, the diamond patterns, and the like is cross arranged on one surface the base substrate  110  to be orthogonal to each other by using a bridge which is an insulating material to form the electrode pattern  120  on the one base substrate  110 , thereby implementing the touch sensor module  1 . 
     The electrode wirings  150  and  160  electrically connect the foregoing electrode patterns  120  and  130  to the flexible cable  300 . The electrode wirings  150  and  160  may be formed on the base substrate  110  by various printing methods, such as a silk screen method, a gravure printing method, and an inkjet printing method (see  FIG. 3 ). Here, the electrode wirings  150 , 160  may be made of copper (Cu), aluminum (Al), gold (Au), silver (Ag), titanium (Ti), palladium (Pd), and chromium (Cr). The electrode wirings  150  and  160  may be made of silver (Ag) paste or organic silver having excellent electrical conductivity. However, the electrode wirings  310  and  320  are not necessarily made of the silver (Ag) paste or the organic silver, but may be made of a conductive polymer, carbon black (including CNT), metal oxide such as ITO, a low resistance metal material such as metals, and the like. 
     The electrode wiring  160  is connected only to one end of the electrode pattern  120  depending on the touch sensor module  1  type. Distal portions of the electrode wirings  150  and  160  are provided with the electrode pads  140  which are electrically connected to the flexible cable  300 . In other words, portions of the electrode wirings  150  and  160  are provided with the electrode pads  140  which are electrically connected to the flexible cable  300 . 
     The electrode pads  140  are disposed on the base substrate  110  while being connected to the electrode wirings  150  and  160  (see  FIG. 3 ). The electrode pad  140  is formed so as not to invade an active region of the flexible cable  300  and the base substrate  110 , that is, a region in which a touch of a user is recognized. The electrode pad  140  is disposed at one end of the base substrate  110  to be connected to the electrode wirings  150  and  160 . The electrode pad  140  contacts the adhesive layer  200  to conduct electricity to the flexible cable  300 . The electrode pad  140  is coupled with the adhesive layer  200  by pressing the flexible cable  300 . In this case, the electrode pad  140  is coupled with the adhesive layer  200  in a stacked direction of the base substrate  110 . The electrode pad  140  is provided with a contact surface which contacts a conductive ball  220  of the adhesive layer  200 . A diameter of the contact surface is formed to be larger than that of the conductive ball  220 . The plurality of electrode pads  140  are disposed at one end of the base substrate  110 . In this case, the electrode pads  140  are formed to be spaced apart from each other at a predetermined distance to prevent an electrical interference from occurring at the adjacent electrode pads. 
     In order to more improve moisture resistance and anti-environment characteristics of the touch sensor module  1 , the passivation layer is used to prevent the infiltration of moisture. 
     The passivation layer  400  is formed to correspond to the electrode pad  140  (see  FIGS. 1 and 2 ). The passivation layer  400  prevents moisture from being infiltrated into the electrode patterns  120  and  130 , the wirings  150  and  160 , and the electrode pad  140 . The passivation layer  400  may have an insulating layer made of silicon dioxide (SiO 2 ) or silicon nitride (SiN) or a composite structure including the same, or may be made of materials such as polyimide and epoxy. 
     A first passivation layer  410  coats one end of the electrode pad  140 . The first passivation layer  410  prevents the infiltration of moisture while protecting an active surface of the electrode patterns  120  and  130  and the electrode pad  140 . The first passivation layer  410  is formed to be larger by 1 to 8 μm than a surface of the electrode pad  140 , in consideration of a hardening rate of the adhesive layer  200 . This resins (seals) an inside of the adhesive layer  200  by pressure at the time of coupling the flexible cable  300 . That is, the electrode pad  140  is protected by preventing external moisture from being infiltrated thereinto along a boundary surface between the flexible cable  300  and the adhesive layer  200 . The first passivation layer  410  prevents moisture from being infiltrated into the surface by coating the electrode patterns  120  and  130 , the wirings  150  and  160 , and the electrode pad  140 . Therefore, the first passivation layer  410  prevents moisture from being infiltrated along the boundary surface between the flexible cable  300  and the adhesive layer  200 , while preventing the moisture from being infiltrated into the surfaces of the electrode patterns  120  and  130  and the wirings  150  and  160 . The first passivation layer  410  coats the flexible cable  300  and the electrode pad  140  to overlap each other, and thus a step is generated due to the first passivation layer  410 , thereby applying a larger pressure. Therefore, the hardening rate of the adhesive layer  200  is more increased due to pressure. Considering the characteristics of the adhesive layer  200 , this prevents moisture and humidity from being infiltrated as the hardening rate is increased, such that the infiltration path into the sensor may be blocked. 
     In some cases, a third passivation layer  450  is formed on the other surface of the base substrate  110  on which the first passivation layer  410  is formed, such that the electrode patterns  120  and  130 , the wirings  150  and  160 , the electrode pad  140 , and the surface of the base substrate  110  may be coated. 
     The adhesive layer  200  is electrically connected the electrode pad  140  by contacting the electrode pad  140 . When the adhesive layer  200  is coupled or adhered by pressure, the conductive ball  220  is disposed therein. The conductive ball  220  conducts electricity in one direction while the electrode pad  140  and the terminal part  320  are adhered to each other by the pressure during the coupling process. A lower section of the adhesive layer  200  is connected to the electrode pad  140  and an upper section of the adhesive layer  200  is adhered to the terminal part  320 . That is, one surface of the conductive ball  220  in the adhesive layer  200  is adhered to the electrode pad  140  and the other surface thereof is adhered to the terminal part  320 . This is to limit the shape in which the adhesive layer  200  is adhered to the electrode pad  140  and the terminal part  320 . 
     The adhesive layer  200  may be preferably formed of an anisotropic conductive film (ACF). In some cases, the adhesive layer  200  may be made of a conductive material such as an anisotropic conductive adhesive (ACA). 
     The flexible cable  300  is correspondingly coupled to the electrode pad  140 . The flexible cable  300  includes terminal parts  320  and  330  which contact the adhesive layer  200 . The flexible cable  300  electrically connects between the electrode patterns  120  and  130  and a control unit (not illustrated) while being electrically connected to the electrode pad  140 . The terminal parts  320  and  330  are electrically connected to the conductive ball  220 . The terminal parts  320  and  330  are formed at a position corresponding to the plurality of electrode pads  140 . The terminal parts  320  and  330  are coupled with the electrode pad  140  by the resin generated due to the pressure at the time of being coupled with the adhesive layer  200 . In this case, when the coupling is easily made due to the step between the terminal parts  320  and  330  and the electrode pad  140 , a force may be equally applied. 
     Referring to  FIG. 4 , in the touch sensor module  1  of a first modification example according to the preferred embodiment of the present invention, the description of the structure and material of the base substrate  110 , the adhesive layer  200 , the flexible cable  300 , and the first passivation layer  410  which are the same components as the first modification example are omitted and the electrode patterns  120  and  130  which are the first modification example according to the preferred embodiment of the present invention will be described in detail. 
     The electrode patterns  120  and  130  are formed on one surface of the base substrate  110 , in which the touch sensor is formed by the electrode patterns  120  and  130  of a single layer. In the touch sensor module of the first modification example according to the preferred embodiment of the present invention, the first electrode pattern  120  in the X-axis direction and the second electrode pattern  130  in the Y-axis direction crossing the first electrode pattern  120  may be formed on the base substrate  110  (see  FIG. 5 ). An insulating pattern I is formed on any one electrode pattern at a portion at which the first electrode pattern  120  and the second electrode pattern  130  cross each other so that the first electrode pattern  120  and the second electrode pattern  130  are formed on the single surface to cross each other, and another electrode pattern is electrically connected on the insulating pattern I, such that the electrical connection between the first electrode pattern  120  and the second electrode pattern  130  which cross each other may be made. A crossing angle between the first electrode pattern  120  and the second electrode pattern  130  which cross each other is perpendicular, but the cross angle is not specifically limited. Therefore, it is preferable to cross the first electrode pattern  120  and the second electrode pattern  130  at a proper angle to extract X-axis and Y-axis coordinates on a two-dimensional plane. 
     The electrode patterns  120  and  130  are formed on one surface of the base substrate  110 . As described above, in the touch sensor module of the first modification example according to the preferred embodiment of the present invention, the first electrode pattern  120  and the second electrode pattern  130  which cross each other may be simultaneously formed on one surface of the base substrate  110 . Herein, the electrode patterns  120  and  130  may be formed in a mesh pattern which is formed as a metal fine line, in which the mesh pattern has a polygonal shape, such as a quadrangular shape, a triangular shape, and a diamond shape, but the shape of the mesh pattern is not particularly limited. The electrode patterns  120  and  130  may be formed in the mesh pattern using copper (Cu), aluminum (Al), gold (Au), silver (Ag), titanium (Ti), palladium (Pd), chromium (Cr), nickel (Ni) or a combination thereof. 
     An example of a method of forming the electrode pattern  120  may include a dry process, a wet process, or a direct patterning process. Here, the dry process includes sputtering, evaporation, and the like, the wet process includes dip coating, spin coating, roll coating, spray coating, and the like, and the direct patterning process means screen printing, gravure printing, inkjet printing, and the like. 
     Referring to  FIG. 6 , in the touch sensor module  1  according to the preferred embodiment of the present invention, the description of the structure and material of the electrode patterns  120  and  130 , the base substrate  110 , the adhesive layer  200 , the flexible cable  300 , and the first passivation layer  410  which are the same components as the preferred embodiment are omitted and a second passivation layer  420  which is the second preferred embodiment of the present invention will be described in detail. 
     The second passivation layer  420  is formed to coat a portion of the other portion of the electrode pad  140 . The second passivation layer  420  coats a portion of the other end of the electrode pad while coating the surface of the base substrate  110 . The second passivation layer  420  is formed to be equal to a height of the first passivation layer  410 . Further, the second passivation layer  420  is formed along an edge of the base substrate  110 . The second passivation layer  420  is formed to have the same height as the first passivation layer  410 . This is to keep an equal pressure when the flexible cable  300  is coupled with the electrode pad  140 . When the flexible cable  300  and the electrode pad  140  are not equally pressed, the flexible cable  300  is tilted in one direction, such that one portion thereof is pressed and the other portion thereof is expanded, thereby causing an electrical short. 
     In some cases, a third passivation layer is formed on the other surface of the base substrate on which the first passivation layer and the second passivation layer are formed, thereby coating the electrode pattern, the wiring, the electrode pad, and the surface of the base substrate. 
     In the touch sensor module  1  of the second modification example according to the preferred embodiment of the present invention, the description of the structure and material of the base substrate  110 , the adhesive layer  200 , the flexible cable  300 , the first passivation layer  410 , and the second passivation layer  420  which are the same components as the second preferred embodiment of the present invention are omitted and the electrode patterns  120  and  130  which are the second modification example according to the preferred embodiment of the present invention will be described in detail. 
     The electrode patterns  120  and  130  are formed on one surface of the base substrate  110 , in which the touch sensor is formed by the electrode patterns  120  and  130  of the single layer. In the touch sensor module of the first modification example according to the preferred embodiment of the present invention, the first electrode pattern  120  in the X-axis direction and the second electrode pattern  130  in the Y-axis direction crossing the first electrode pattern  120  may be formed on the base substrate  110  (see  FIG. 5 ). The insulating pattern I is formed on any one electrode pattern at the portion at which the first electrode pattern  120  and the second electrode pattern  130  cross each other so that the first electrode pattern  120  and the second electrode pattern  130  are formed on the single surface to cross each other, and another electrode pattern is electrically connected on the insulating pattern I, such that the electrical connection between the first electrode pattern  120  and the second electrode pattern  130  which cross each other may be made. The crossing angle between the first electrode pattern  120  and the second electrode pattern  130  which cross each other is perpendicular, but the cross angle is not specifically limited. Therefore, it is preferable to cross the first electrode pattern  120  and the second electrode pattern  130  at a proper angle to extract X-axis and Y-axis coordinates on a two-dimensional plane. The method of forming the electrode patterns  120  and  130  and the material thereof are the same as the electrode pattern of the first modification example as described above and therefore are omitted. 
     According to the preferred embodiments of the present invention, it is possible to prevent the short-circuit and the poor contact between the electrode pad and the FPCB by forming the passivation layers at both ends of the electrode pad. 
     Further, it is possible to prevent the electrical short-circuit between the electrode pad and the FPCB by forming the passivation layers at both ends of the electrode pad, thereby securing the reliability of products. 
     In addition, it is possible to prevent the distortion and tilting of the FPCB due to the pressure generated at the time of the coupling between the electrode pad and the FPCB, by forming the passivation layers at both ends of the electrode pad. 
     Moreover, it is possible to prevent the infiltration of moisture in both directions of electrode pad and the FPCB by forming the passivation layers at both ends of the electrode pad. 
     Also, it is possible to form the resin of the ACF ball in both directions of the electrode pad and the FPCB to prevent the short-circuit of the electrode pattern, by forming the passivation layers at both ends of the electrode pad. 
     Although the embodiments of the present invention have been disclosed for illustrative purposes, it will be appreciated that the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention. 
     Accordingly, any and all modifications, variations or equivalent arrangements should be considered to be within the scope of the invention, and the detailed scope of the invention will be disclosed by the accompanying claims.