Patent Publication Number: US-2020282206-A1

Title: Electrode array and bioartificial implant system including the same

Description:
BACKGROUND 
     1. Field of the Invention 
     Exemplary embodiments relate to an electrode array and a bioartificial implant system including the same. 
     2. Discussion of Related Art 
     Many medical devices have been developed to help people who have lost a specific function due to either a congenital or acquired cause. As such a medical device, bioartificial implant systems including nerve assist devices have also been developed. 
     A cochlear implant device, which is one of the bioartificial implant systems that helps people whose auditory nerve function is intact to hear a sound by stimulating the auditory nerve with electricity, is perceived as the most effective device among the nerve assist devices developed so far. Transplant operations of the cochlear implant device are rising every year. 
     The cochlear implant device may include an external device provided outside the body part and an internal device provided inside the body part. 
     The external device serves to receive a sound from the outside of the human body and convert the received sound into an electrical signal. The external device may include a microphone (voice transmitter), a speech processor (language synthesizer), and a transmission antenna (transmitter). In this case, the microphone and the transmission antenna may be configured by being combined with a headset. 
     The internal device serves to stimulate the auditory nerve in response to a signal transmitted from the external device. The internal device may include a voice receiver and an electrode for reception and stimulation. 
     The cochlear implant device may convert a sound signal transmitted to the microphone attached to an exterior of the human body into an electrical signal for physical vibration through amplification and filtration in a speech processor without a tympanic membrane or auditory ossicles, thereby transmitting the converted electrical signal to an auditory nerve fiber through an electrode implanted in a cochlea. 
     However, since a conventional electrode is manufactured so that a platinum electrode and a wire are manually aligned and silicon-molded, there is a problem in that a cost and a time are increased and a yield is lowered. Further, since an area of the conventional electrode is small, there is a problem in that a current stimulus is relatively small. 
     SUMMARY OF THE INVENTION 
     The exemplary embodiments are directed to an electrode array which is easily manufactured, and a bioartificial implant system including the same. 
     Further, the exemplary embodiments are directed to an electrode array having an electrode with a wide area so as to be able to apply a relatively large current stimulus, and bioartificial implant system including the same. 
     According to an aspect of the present invention, there is provided an electrode array including a body including a first groove extending in a first direction, a substrate disposed on the first groove, a plurality of lines disposed on one surface of the substrate, a plurality of electrodes disposed to be spaced apart from each other on the substrate in the first direction, and a mold member configured to fix the plurality of electrodes to the body, wherein each of the plurality of electrodes includes a stimulation portion exposed to an outer side of the mold member and a first end portion electrically connecting the stimulation portion to the plurality of lines. 
     Each of the plurality of electrodes may include a connecting portion bent upward from the first end portion and include the stimulation portion disposed to face the substrate from the connecting portion. 
     A deformed portion by being partially heated may be included between the connecting portion and the first end portion and between the connecting portion and the stimulation portion. 
     The deformed portion may be formed to extend in the first direction. 
     Each of the plurality of electrodes may include a second end portion bent downward from the stimulation portion toward the substrate. 
     One surface of the stimulation portion may be disposed to be higher than the first groove. 
     One surface of the stimulation portion may be disposed to be lower than the first groove. 
     The electrode array may include a cover disposed on the substrate and configured to cover the first end portion of each of the plurality of electrodes. 
     Each of the substrate and the cover may have a first cross-sectional area, in which the plurality of electrodes are disposed, that is greater than a second cross-sectional area between the plurality of electrodes. 
     Each of the plurality of electrodes may include platinum (Pt) and iridium (Ir). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which: 
         FIG. 1  is a conceptual diagram of a bioartificial implant system according to one embodiment of the present invention; 
         FIG. 2  is an exemplary diagram illustrating a case in which a second unit of the bioartificial implant system according to one embodiment of the present invention is applied to a human body; 
         FIG. 3  is a conceptual diagram of the second unit according to one embodiment of the present invention; 
         FIG. 4  is a conceptual diagram of an electrode array according to one embodiment of the present invention; 
         FIG. 5  is a diagram illustrating an arrangement of a plurality of electrodes of  FIG. 4 ; 
         FIG. 6  is a cross-sectional view taken along line A-A of  FIG. 4 ; 
         FIG. 7  is a diagram illustrating the electrodes formed on a substrate; 
         FIG. 8  is a diagram illustrating a cover formed on the substrate on which the electrodes are formed; 
         FIG. 9  is a diagram illustrating a case in which the substrate and the cover are partially incised to expose the electrodes; 
         FIG. 10  is a diagram illustrating a process of irradiating a laser in a direction perpendicular to an extension direction of the substrate; 
         FIG. 11  is a diagram illustrating a state in which the electrode is bent by laser irradiation; 
         FIG. 12  is a diagram illustrating a process of manufacturing a body; 
         FIG. 13  is a diagram illustrating a state in which a first groove is formed in the body; 
         FIG. 14  is a diagram illustrating a process of disposing the electrodes in the body; 
         FIG. 15  is a diagram of a process of fixing the electrodes to the body with a mold member; 
         FIG. 16  is a conceptual diagram of an electrode array according to another embodiment of the present invention; 
         FIG. 17  is a cross-sectional view taken along line B-B of  FIG. 16 ; 
         FIG. 18  is a cross-sectional view taken along line C-C of  FIG. 16 ; 
         FIG. 19  is a diagram illustrating a process of bending an exposed electrode; 
         FIG. 20  is a diagram illustrating a process of disposing electrodes on a manufactured body; 
         FIG. 21  is a diagram illustrating a process of filling a mold member to fix the electrodes to the body; 
         FIG. 22  is a conceptual diagram of an electrode array according to still another embodiment of the present invention; 
         FIG. 23  is a diagram illustrating an arrangement of a plurality of electrodes of  FIG. 22 ; 
         FIG. 24  is a cross-sectional view taken along line D-D of  FIG. 22 ; and 
         FIG. 25  is a cross-sectional view taken along line E-E of  FIG. 22 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and thus it is not limited to exemplary embodiments which will be described herein. In the drawings, some portions not related to the description will be omitted in order to clearly describe the present invention, and similar reference numerals are given to similar components throughout this disclosure. 
     Throughout this disclosure, when a portion is referred to as being “connected to” another portion, this includes not only “being directly connected to” but also “being indirectly connected to” by interposing another member between the portion and another portion. Also, when a portion is referred to as “including” a component, it may mean that another component is further included and is not to be excluded unless specifically stated otherwise. 
     In addition, the following exemplary embodiments are illustrative, and thus the scope of the present invention is not limited thereto, and configurations of the exemplary embodiments may be combined with each other to constitute a new exemplary embodiment. Further, it should be understood that the detailed configurations which can be easily substituted and/or modified by those skilled in the art although not described in detail in this disclosure can be applicable to the exemplary embodiments of the present invention, and also details of the exemplary embodiments of the present invention are illustrative. 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a conceptual diagram of a bioartificial implant system according to one embodiment of the present invention,  FIG. 2  is an exemplary diagram illustrating a case in which a second unit of the bioartificial implant system according to one embodiment of the present invention is applied to a human body, and  FIG. 3  is a conceptual diagram of the second unit according to one embodiment of the present invention; 
     Referring to  FIG. 1 , a bioartificial implant system according to an embodiment may include a first unit  100  and a second unit  200  which are communicatable with each other. Hereinafter, an example of a cochlear implant system, which is one of bioartificial implant systems, will be described. However, the present embodiment is not limited thereto. For example, the second unit  200  may be a device for providing an electrical signal to other parts or organs of the human body. 
     The first unit  100  may convert a sound signal into an electrical signal to provide the converted electrical signal and may include a first coil  140  provided outside a person&#39;s skin and configured to supply electric power. The first unit  100  may be disposed outside the skin. That is, the first unit  100  may be installed outside the human body instead of being implanted in the human body. 
     The first unit  100  may include a voice transmitter  110 , a voice processor  120 , a transmitter  130 , and the first coil  140 . 
     The voice transmitter  110  may detect an external sound signal. The sound signal may include a voice signal or an acoustic signal. Various electronic devices capable of detecting a sound signal may be selected as the voice transmitter  110 . 
     The voice processor  120  may receive the sound signal detected by the voice transmitter  110  and convert the received sound signal into an electrical signal. The voice processor  120  may include a speech processor. 
     The transmitter  130  may receive the electrical signal from the voice processor  120  and transmit the received electrical signal. The first coil  140  may supply electric power. However, the present invention is not particularly limited thereto, and the transmitter  130  may be omitted. That is, the first unit  100  may not include a separate transmitter  130 . In this case, the first unit  100  may receive the electrical signal from the voice processor  120  and transmit the received electrical signal to the second unit  200  through the first coil  140  along with electrical power transmission. 
     The first unit  100  may include a power supplier (not shown). The power supplier is a configuration for supplying electric power to the first unit  100 . The power supplier may include a replaceable battery or a rechargeable battery. 
     The power supplier may receive electric power from the outside and store the electric power therein. For example, the power supplier may include a capacitive element such as a capacitor. The capacitive element may receive electric power through wires from an external power supplier and store the received electric power therein. Alternatively, the capacitive element may receive electric power from an external power supplier through the first coil  140  of the first unit  100  in a wireless manner. 
     For example, the first coil  140  may receive wirelessly electric power from a coil of the external power supplier through electromagnetic induction in a charging mode and store the received electric power in the capacitive element. In a transmission mode, the first coil  140  may transmit the electric power stored in the capacitive element to a second coil  240  of the second unit  200  in a wireless manner. 
     In this case, the transmission of electric power through the coil may use an electromagnetic induction phenomenon, but the present invention is not limited thereto, and other types of wireless power transmission techniques may be used. 
     The second unit  200  may be inserted into the skin. For example, the second unit  200  may be inserted into the subcutaneous fat layer or may be implanted into the human body. 
     The second unit  200  may receive the electrical signal from the first unit  100  to stimulate an auditory nerve fiber in a cochlea  10 . 
     The second unit  200  may include a receiver  230 , a circuit part  220  for processing a signal received from the first unit  100  to generate a stimulation signal, and an electrode array  210  having a plurality of electrodes (not shown) for stimulating the auditory nerve fiber in the cochlea  10  according to the stimulation signal transmitted from the circuit part  220 . 
     The receiver  230  may receive a signal from the first unit  100 . For example, the receiver  230  may include the second coil  240  for receiving a signal with electric power from the first coil  140 . When the first coil  140  of the first unit  100  transmits the electric power, the first coil  140  may transmit a data signal for electrical stimulation together with an electric power signal. For example, the first coil  140  may transmit the electric power together with the data signal by varying an amplitude or a phase of the electric power signal. 
     Alternatively, the receiver  230  may directly receive a signal from the transmitter  130  of the first unit  100 . The transmitter  130  and the receiver  230  may communicate with each other through various communication technologies which are not limited to specific communication technology. Alternatively, it is also possible to communicate the data signal separately from the electric power signal via a separate communication means or a separate frequency that is not described above. 
     The circuit part  220  may process the signal received at the receiver  230  to generate a stimulation signal. The circuit part  220  may include an integrated circuit (IC) for generating a stimulation signal. 
     The electrode array  210  may have a structure in which a plurality of electrodes (not shown) are disposed on an insulating layer. The electrode array  210  may be formed to be thin enough to be inserted into the cochlea  10  of the human body. 
     Referring to  FIG. 3 , the receiver  230  and the circuit part  220  of the second unit  200  may be disposed on a support substrate and may be accommodated in a housing  250 . The housing  250  may be made of a material that is identical to a polymer material of the support substrate, but the present invention is not particularly limited thereto. 
     The electrode array  210  may be formed to extend in a first direction (X-axis direction). An extension length of the electrode array  210  is not particularly limited. The electrode array  210  may have a predetermined length which is inserted into the cochlea  10  of the human body so as to be able to make stimulation. 
     A plurality of electrodes  213  may be applied with a current signal transmitted from the circuit part  220  to stimulate an auditory nerve fiber in the cochlea  10 . Further, the plurality of electrodes  213  may collect, detect, and record a biological signal from the auditory nerve fiber. 
       FIG. 4  is a conceptual diagram of an electrode array according to one embodiment of the present invention,  FIG. 5  is a diagram illustrating an arrangement of a plurality of electrodes of  FIG. 4 , and  FIG. 6  is a cross-sectional view taken along line A-A of  FIG. 4 ; 
     Referring to  FIGS. 4 to 6 , the electrode array  210  according to the present embodiment includes a body  215  having a first groove H 1  extending in the first direction (X-axis direction), a substrate  211  disposed in the first groove H 1 , a plurality of lines  212  disposed on one surface of the substrate  211 , the plurality of electrodes  213  disposed to be spaced apart from each other on the substrate  211  in the first direction, and a mold member  216  for fixing the plurality of electrodes  213  to the body  215 . 
     The electrode array  210  may be formed to extend in the first direction (X-axis direction). A length of the electrode array  210  is not particularly limited. The electrode array  210  may be formed to be thin enough to be inserted into the cochlea  10  of the human body and formed so as to be able to make stimulation. 
     The body  215  may form an appearance of the electrode array  210  and accommodate the plurality of electrodes  213 . The substrate  211  included in the body  215  may be made of a polymer material, but present invention is not limited thereto. For example, the body  215  may be made of a liquid crystal polymer (LCP) material. In addition to the LCP material, various polymers may be selected as a material of the body  215 . For example, a polymer such as parylene, a cyclo olefin polymer (COP), a cyclic olefin copolymer (COC), or the like may be selected as a material of the substrate  211 . 
     The plurality of electrodes  213  may be disposed to be spaced apart from each other in the first direction. Areas of and intervals between the plurality of electrodes  213  are not particularly limited. The plurality of electrodes  213  may be fixed to the body  215  by the mold member  216 . 
     Referring to  FIGS. 5 and 6 , the substrate  211  may be disposed in the first groove H 1 . The substrate  211  may be made of an LCP material, but the present invention is not particularly limited thereto. The substrate  211  may employ any material as long as it can be easily patterned and is flexible. 
     A cover  214  may be disposed on the substrate  211 . The cover  214  may be made of a material that is identical to that of the substrate  211 . The plurality of lines  212  and the plurality of electrodes  213  may be stacked between the substrate  211  and the cover  214 . A conventional lamination method may be applied to both of the plurality of lines  212  and the plurality of electrodes  213 . 
     The mold member  216  may fill in the first groove H 1  to fix the substrate  211  and the electrodes  213  to the first groove H 1 . The mold member  216  may be made of a material that is identical to that of the body  215 . 
     The plurality of electrodes  213  may be respectively electrically connected to the plurality of lines  212 . Thus, a current may be selectively applied to the plurality of electrodes  213 . 
     The plurality of electrodes  213  may extend from a side surface of the substrate  211  to be bent to face one surface of the substrate  211 . Therefore, an area of the electrode  213  may become larger as compared to a structure in which the electrode  213  is formed on the substrate  211 . 
     The plurality of electrodes  213  may include a stimulation portion  213 - 1  exposed to an outer side of the mold member  216 , a first end portion  213 - 2  for electrically connecting the stimulation portion  213 - 1  to the line  212 , and a connecting portion  213 - 3  bent upward from the first end portion  213 - 2 . 
     The stimulation portion  213 - 1  may be defined as a position which is exposed to the outside of the mold member  216  and from which electrical stimulation is able to be applied. According to the present embodiment, the electrode  213  may be disposed to be bent about the substrate  211  and an upper end portion of the electrode  213  may be exposed from the mold member  216 . With the above-described configuration, there is an advantage in that the electrode  213  having a large area may be exposed to the outside while the substrate  211  may be stably fixed in the body  215 . 
     One surface S 2  of the stimulation portion  213 - 1  may be fixed by the mold member  216  and may disposed to face the substrate  211 . Further, the other surface S 1  may be exposed to the outside to transmit stimulation to the human body when an electrical signal is applied. 
     The first end portion  213 - 2  may be electrically connected to the line  212  disposed on the substrate  211 , and the connecting portion  213 - 3  may be bent upward for the first end portion  213 - 2  to form a space between the stimulation portion  213 - 1  and the substrate  211 . The mold member  216  may be disposed in the space between the stimulation portion  213 - 1  and the substrate  211 . 
     A second end portion  213 - 4  may be bent downward from the stimulation portion  213 - 1  toward the substrate  211 . Accordingly, the second end portion  213 - 4  may be fixed to an interior of the mold member  216 . Thus, the first end portion  213 - 2  and the second end portion  213 - 4  may be stably fixed to the interior of the mold member  216 . 
     The mold member  216  may include a first mold part  216   a  disposed inside a bent electrode  213  and a second mold part  216   b  disposed between an exterior of the electrode  213  and the first groove H 1 . The first mold part  216   a  may be connected to the second mold part  216   b.  With the above-described configuration, the mold member  216  may be uniformly disposed in an interior and the exterior of the electrode  213  to be stably fixed. 
     The plurality of electrodes  213  may each include deformed portions P 1 , P 2 , and P 3  which are made of being partially heated. The deformed portions P 1 , P 2 , and P 3  may be disposed at regions at which the electrode  213  is bent. For example, the deformed portions P 2  and P 3  may be disposed between the connecting portion  213 - 3  and the stimulation portion  213 - 1  and between the stimulation portion  213 - 1  and the second end portion  213 - 4 . 
     The deformed portions P 1 , P 2 , and P 3  may be heated by laser irradiation to cause local bending of the electrode  213 . In this case, the deformed portions P 1 , P 2 , and P 3  may be formed to extend in the first direction. 
     However, the present invention is not limited thereto, and the deformed portions P 1 , P 2 , and P 3  may be deformed due to different causes. For example, the first deformed portion P 1  and the third deformed portion P 3  may be partially heated by laser irradiation to cause bending, whereas the second deformed portion P 2  may be bent by an external physical force. Thus, metal structures in the first and third deformed portions P 1  and P 3  may be different from a metal structure of the second deformed portion P 2 . 
       FIGS. 7 to 15  are diagrams for describing a method of manufacturing an electrode array according to one embodiment of the present invention. 
     Referring to  FIG. 7 , after an electrode layer is entirely formed on the substrate  211 , the plurality of lines  212  and the plurality of electrodes  213  may be patterned. A patterning method is not particularly limited. All conventional patterning methods used in a semiconductor manufacturing process may be applied. For example, patterning may be performed by selective etching using a mask. 
     The substrate  211  may be made of an LCP material, but the present invention is not particularly limited thereto. The substrate  211  may employ any material as long as it can be easily patterned and is flexible. 
     For example, the first electrode  213   a  may be connected to a first line  212   a,  a second electrode  213   b  may be connected to a second line  212   b,  and a third electrode  213   c  may be connected to a third line  212   c.  Consequently, the first electrode  213   a  to the third electrode  213   c  may be separately driven. 
     Referring to  FIG. 8 , the cover  214  may be formed on the substrate  211 . The cover  214  may be made of a material that is identical to that of the substrate  211 . The plurality of lines  212  and the plurality of electrodes  213  may be stacked between the substrate  211  and the cover  214 . A conventional lamination method may be applied to both of the plurality of lines  212  and the plurality of electrodes  213 . 
     Referring to  FIG. 9 , some portion of the cover  214  and the substrate  211  may be incised to expose portions of the plurality of electrodes  213 . The cover  214  and the substrate  211  may be removed using laser scribing or etching. For example, the cover  214  and substrate  211  may be removed using laser scribing. In this case, a surface of the electrode  213  should not be reacted with a laser beam so that an irradiation time of a laser may be controlled to be very short. However, a method of removing the cover  214  and the substrate  211  is not particularly limited thereto. In this case, the plurality of electrodes  213  may be defined as regions exposed to the outer side of the substrate  211 . Thus, the plurality of electrodes  213  may have the same area. 
     Referring to  FIGS. 10 and 11 , the plurality of electrodes  213  may be irradiated with a laser to cause bending by partially heating the plurality of electrodes  213 . When a concentration of the laser is high, the electrode  213  may be separated due to high energy so that an output of the laser may be lowered using a defocusing lens or the like. 
     The output of the laser may be in the range of 0.4 W to 10 W. When the output is 0.4 W or less, the electrode  213  is not heated so that bending does not occur, whereas when the output is 10 W or more, an intensity of the laser is too high so that the electrode  213  may be cut. 
     The laser may be irradiated in the first direction (X-axis direction). Accordingly, the deformed portions P 1  and P 3  formed on the plurality of electrodes  213  may be formed in the extension direction of the substrate  211 . Further, the laser may be irradiated with the number of times L 1  and L 2  in a second direction (Y-axis direction) perpendicular to the extension direction of the substrate  211 . 
     Referring to  FIG. 11 , the electrode  213  may be bent due to the plurality of deformed portions P 1  and P 3 . According to the present embodiment, since the electrode  213  is bent when the laser is irradiated, there may be an advantage of simplifying a process of manually bending the plurality of electrodes  213 . 
     Referring to  FIGS. 12 and 13 , the body  215  may be formed by injecting a mold resin between a first cast C 1  and a second cast C 2 . In this case, the first groove H 1  may be formed in the body  215 . 
     Referring to  FIG. 14 , after the substrate  211  and the plurality of electrodes  213  are disposed in the first groove H 1 , the plurality of electrodes  213  may be inserted into the first groove H 1 . When a portion of the electrode  213  is not inserted into the first groove H 1 , the electrode  213  may be inserted into the first groove H 1  by a manual operation or a machine. 
     Referring to  FIG. 15 , the mold member  216  may be formed by covering the first cast C 1  with a third cast C 3  and injecting a mold resin therebetween. In this case, the electrode  213  is bent such that the mold resin may be injected into an inner space formed by the electrode  213  being bent. 
       FIG. 16  is a conceptual diagram of an electrode array according to another embodiment of the present invention,  FIG. 17  is a cross-sectional view taken along line B-B of  FIG. 16 ,  FIG. 18  is a cross-sectional view taken along line C-C of  FIG. 16 , and  FIG. 19  is a diagram illustrating a process of bending an exposed electrode. 
     Referring to  FIGS. 16 to 18 , the electrode  213  may include a stimulation portion  213 - 1  exposed to the outside of the mold member  216  and include a first end portion  213 - 2  connecting the stimulation portion  213 - 1  to the line  212  of the substrate  211 . 
     According to the present embodiment, the electrode  213  may be exposed on the side surface of the substrate  211  to be bent to face one surface of the substrate  211 . According to the present embodiment, it is possible to maximally bend the electrode  213  toward the substrate  211  without applying bending due to laser irradiation. Therefore, the stimulation portion  213 - 1  of the electrode  213  may be disposed lower than the first groove H 1 . A gap T 1  between an upper surface of the first groove H 1  and the stimulation portion  213 - 1  may be in the range of 10 μm to 20 μm. With the above-described configuration, as shown in  FIG. 18 , it is possible to secure a thickness of the mold member  216  formed on the substrate  211  to stably fix the substrate  211 . With the above-described structure, there is an advantage of simplifying the process of bending the electrode  213 . 
     Referring to  FIG. 19 , a method of exposing the electrode  213  by incising the substrate  211  and the cover  214  may be identical to the method described with reference to  FIGS. 7 to 9 . Thereafter, the exposed electrode  213  may be bent toward the substrate  211 . In this case, as described above, the laser may be defocused to bend the electrode  213 . Alternatively, the electrode  213  may be bent by a machine or a manual operation. Referring to  FIG. 20 , the substrate  211  and the electrode  213  may be disposed on a body  215 , and then a mold resin may be injected as shown in  FIG. 21  to manufacture the electrode array  210 . 
       FIG. 22  is a conceptual diagram of an electrode array according to still another embodiment of the present invention,  FIG. 23  is a diagram illustrating an arrangement of a plurality of electrodes of  FIG. 22 ,  FIG. 24  is a cross-sectional view taken along line D-D of  FIG. 22 , and  FIG. 25  is a cross-sectional view taken along line E-E of  FIG. 22 . 
     Referring to  FIGS. 22 to 24 , the substrate  211  and the cover  214  may include a first portion  217   a  in which the plurality of electrodes  213  are disposed, and a second portion  217   b  in which the plurality of electrodes  213  are not disposed. A first cross-sectional area of the first portion  217   a  may be greater than a second cross-sectional area of the second portion  217   b.  The first cross-sectional area and the second cross-sectional area may be adjusted using a semiconductor pattern process. 
     With the above-described configuration, as shown in  FIG. 24 , there may be an advantage in that the first portion  217   a,  in which the plurality of electrodes  213  are disposed, is manufactured to be relatively thicker and is brought into close contact with a first groove, whereas as shown in  FIG. 25 , the second portion  217   b  disposed between the first portions  217   a  is stably fixed by being completely surrounded by the mold member  216 . 
     With the above-described structure, since a portion at which the electrode  213  is not formed is manufactured to be relatively thin, there may be an advantage in that the second portion  217   b  not having the electrode  213  is sufficiently covered even though a mold member  216  is only formed to completely enclose a bent position of the electrode  213 . 
     According to the exemplary embodiments, it is possible to easily manufacture an electrode array by injecting a mold member into an electrode. 
     Further, an area of an electrode is widened such that a relatively large current stimulus can be applied. 
     It should be understood that effects of the present invention are not limited to the above-described effect and include all effects that can be deduced from the detailed description of the present invention or the configuration thereof defined by the appended claims. 
     The above-described description of the present invention is intended only for an illustrative purpose, and it can be easily understood that other concrete forms can be devised by those skilled in the art without changing or modifying the technical spirit or essential characteristics of the present invention. 
     Therefore, it should be understood that the above-described embodiments are not restrictive but illustrative in all aspects. For example, each component described as a single form may be distributed and implemented, and similarly, components described as being distributed may also be implemented in a combined form. 
     The scope of the present invention is defined by the appended claims, and all alternations or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.