Patent ID: 12211630

DETAILED DESCRIPTION

Embodiments of the inventive concept will be described with reference to the accompanying drawings so as to sufficiently understand constitutions and effects of the inventive concept. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Further, the present invention is only defined by scopes of claims. A person with ordinary skill in the technical field of the present invention pertains will be understood that the present invention can be carried out under any appropriate environments.

In the following description, the technical terms are used only for explaining a specific exemplary embodiment while not limiting the present invention. In this specification, the terms of a singular form may comprise plural forms unless specifically mentioned. As used in this specification, the meaning of ‘comprises’ and/or ‘comprising’ specifies a component, a step, an operation and/or an element does not exclude other components, steps, operations and/or elements.

In the specification, it will be understood that when a layer (or film) is referred to as being ‘on’ another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present.

In this specification, each of phrases such as “A or B”, “at least one of A or B”, “at least one of A or B”, “A, B or C”, at least one of “A, B and C”, or at least one of “A, B, or C” may include any one of, or all possible combinations of, items listed together in the corresponding one of the phrases, or all possible combinations thereof.

Also, though terms like a first, a second, and a third are used to describe various regions and layers (or films) in various embodiments of the present invention, the regions and the layers are not limited to these terms. These terms are used only to discriminate one area or layer (or film) from another area or layer (or film). Therefore, a layer referred to as a first layer in one embodiment can be referred to as a second layer in another embodiment. An embodiment described and exemplified herein includes a complementary embodiment thereof. Throughout the specification, like reference numerals in the drawings denote like elements.

Unless terms used in embodiments of the present invention are differently defined, the terms may be construed as meanings that are commonly known to a person skilled in the art.

Hereinafter, stretchable electronics and a method for manufacturing the same according to the inventive concept will be described with reference to the drawings.

Stretchable electronics may be expanded or contracted in at least one direction by external force. For example, the stretchable electronics may be expanded or contracted in a longitudinal direction. However, in some embodiments, the stretchable electronics may be expanded or contracted in all directions. A shape of the stretchable electronics may be freely deformed. The stretchable electronics may refer to an output device capable of outputting visual information even if the shape is deformed. Thus, the stretchable electronics may be disposed on an uneven surface. The stretchable electronics may be deformed in shape according to a surface on which the stretchable electronics is disposed. The stretchable electronics may be reversibly stretched. For example, when external force is applied to the stretchable electronics, the stretchable electronics may be stretched, and when the external force is removed, the stretchable electronics may return to its original shape. Thus, the stretchable electronics may be repeatedly stretched. The stretchable electronics may be used for an output device. The stretchable electronics may be used as a wearable communication device, a body-embedded or attachable bio device, and the like. The application of the stretchable electronics is not limited thereto.

FIG.1is a plan view of stretchable electronics according to embodiments of the inventive concept. AlthoughFIG.1schematically illustrates a shape of a wire structure for convenience, the shape according to embodiments of the inventive concept is not limited to that illustrated inFIG.1.

Referring toFIG.1, stretchable electronics may include a substrate100, an electronic element200, and wire structures300. The substrate100may include a flexible substrate. For example, the substrate100may be made of an elastomer. The substrate100may be made of polydimethylsiloxane (PDMS) or polyurethane (PU). However, in embodiment of the inventive concept, the material of the substrate100is not limited thereto, and the substrate100may be made of various materials that are used as a flexible substrate. The substrate100may be an elastomer having a lower Young's modulus than that of an insulator to be described later. Young's modulus is an elastic modulus that defines the relationship between force per unit applied to an elastic material and a strain rate. Thus, the substrate100may be more easily deformed than the insulator during the stretching.

The substrate100may be expanded or contracted by external force. Here, the substrate100may be expanded or contracted in one direction or both directions, or differently, the substrate100may be expanded or contracted in all directions. The substrate100may be deformed in shape according to the extension or contraction of the stretchable electronics. The substrate100may be provided to support or protect various components of the stretchable electronics.

A plurality of electronic elements200may be disposed on the substrate100. The plurality of electronic elements200may be arranged to be spaced apart from each other on the substrate100. The plurality of electronic elements200may be arranged in a first direction and a second direction, which are parallel to a top surface of the substrate100and cross each other. For example, as illustrated inFIG.1, the plurality of electronic elements200may be arranged in the form of a lattice along the first direction and the second direction. However, an embodiment of the inventive concept is not limited thereto, and the plurality of electronic elements200may be arranged in various shapes as necessary. The plurality of electronic elements200may include a plurality of insulating layers and a plurality of conductive layers. Each of the plurality of electronic elements200may include a thin film transistor. A light emitting element electrically connected to the thin film transistor may be further provided on each of the plurality of electronic elements200. The light emitting element may be an organic light emitting diode (OLED) or a micro light emitting diode (micro-LED).

The wire structures300may be disposed on the substrate100. The wire structures300may be connected to the plurality of electronic elements200, respectively. For example, a pair of adjacent electronic elements200may be connected to both ends of one wire structure300, respectively. The electronic elements200arranged in the first direction and the second direction may be connected by the wire structures300. The wire structures300may electrically connect the plurality of electronic elements200to each other.

The shapes and numbers of the substrate100, the plurality of electronic elements200, and the wire structures300illustrated inFIG.1may be provided as examples, and thus, the shapes and numbers of the substrate100, the plurality of electronic elements200and the wire structure may be variously changed as necessary.

Hereinafter, the shapes of the wire structures300will be described based on one wire structure300. The wire structure300may extend from one electronic element200to another adjacent electronic element200. The wire structure300may be expanded or contracted in at least one direction. For example, the wire structure300may be expanded or contracted between the one electronic element200and the other electronic element200, and thus, an interval between the one electronic element200and the other electronic element200may be increased or decreased. When the wire structure300is expanded in a direction that is away from the one electronic element200and the other electronic element200, the wire structure300may be deformed in a straight line shape. The wire structure300may have a structure that relieves stress applied to the wire structure300when the wire structure300is contracted or expanded by external force. This will be described in detail later. The wire structure300may include one insulator and one or more metal wires. Hereinafter, the structure of the wire structure300will be described in detail.

FIG.2is a perspective view of the stretchable electronics according to embodiments of the inventive concept.FIG.3is a cross-sectional view of the stretchable electronics according to embodiments of the inventive concept and corresponds to a vertical cross-section of the wire structure of the stretchable electronics ofFIG.2.

Referring toFIGS.2and3, the wire structure300may be provided on the substrate100. The wire structure300may include an insulator320. A bottom surface of the insulator320may be in contact with the top surface of the substrate100. The insulator320may include a top surface opposite to the bottom surface. The insulator320may include side surfaces that face each other. The insulator320may be provided to support the metal wire310. The insulator320may extend from one electronic element200to another adjacent electronic element200.

The insulator320may include at least one bent part in a plan view. In an embodiment, the bent part may be provided in plurality. However, the shape of the insulator320is not limited to the shape illustrated inFIG.2, and the insulator320may include various shapes having bent parts. For example, the insulator320may have a serpentine shape, a zigzag shape, a spiral shape, and a spring shape. The cross-sectional shape of the insulator320may be a rectangular shape. As illustrated inFIG.3, the insulator320has the rectangular cross-sectional shape, but an embodiment of the inventive concept is not limited thereto.

The insulator320may be made of an insulating material. The insulator320may be made of a flexible material. The insulator320may be a patternable material. For example, the insulator320may be a polymer material. The insulator320may be made of polyimide. However, the material of the insulator320is not limited thereto.

The metal wire310may be provided on the top surface and side surfaces of the insulator320. The metal wire310may cover the entirety of the top surface and the side surfaces of the insulator320. For example, a portion of the metal wire310disposed on the top surface of the insulator320and other portions of the metal wire310disposed on the side surfaces of the insulator320may be connected to each other. The metal wire310may extend from one of the side surfaces of the insulator320through the top surface of the insulator320to the other one of the side surfaces of the insulator320. The insulator320may be embedded by the metal wire310on the substrate100, and the top surface and the side surfaces of the insulator320may not be exposed by the metal wire310. The shape of the metal wire310may be defined according to the shape of the insulator320. For example, since the insulator320includes the bent portion in the plan view, the metal wire310may also include a bent portion in the plan view. In addition, the metal wire310may extend along the direction in which the insulator320extends. The metal wire310may be a wire for electrically connecting the plurality of electronic elements200(seeFIG.1) to each other. The metal wire310may include a conductive material. The metal wire310may include copper (Cu) or aluminum (Al), but an embodiment of the inventive concept is not limited thereto, and metals capable of conducting electricity may be provided.

FIG.3illustrates that the insulator320is embedded by the metal wire310, but an embodiment of the inventive concept is not limited thereto.FIG.4is a cross-sectional view of stretchable electronics according to embodiments of the inventive concept. In the following embodiments, the components described in the embodiments ofFIGS.1and2use the same reference numerals, and descriptions thereof are omitted or briefly described for convenience of description. That is, differences between the embodiments ofFIGS.1and2and the following embodiments will be mainly described.

Referring toFIG.4, a metal wire310may expose a portion of an insulator320. For example, the portion exposed by the metal wire310may be a portion of a top surface of the insulator320. In more detail, as illustrated inFIG.4, the metal wire310may include a first metal wire310a, a second metal wire310b, and a third metal wire310c. The first metal wire310amay be provided on the top surface of the insulator320. The second metal wire310band the third metal wire310cmay be provided on side surfaces of the insulator320, respectively. The second metal wire310band the third metal wire310cmay be disposed on the side surfaces that face each other. A width of the first metal wire310amay be less than that of the insulator320. In this case, the first metal wire310amay be spaced apart from the side surfaces of the insulator320. Thus, the first metal wire310amay be spaced apart from the second metal wire310band the third metal wire310c. The first metal wire310a, the second metal wire310b, and the third metal wire310cmay extend along a direction in which the insulator320extends. As illustrated inFIG.4, the three metal wires310a,310b, and310cmay be provided in one insulator320, but an embodiment of the inventive concept is not limited thereto. For example, four or more metal wires may be provided.

The electronic elements200(seeFIG.1) are electrically connected to each other by the metal wires310a,310b, and310cspaced apart from each other, and thus, the metal wires310a,310b, and310cmay provide a plurality of electrical paths on one insulator. In general, a plurality of signal wires is required to drive a display. According to embodiments of the inventive concept, the metal wires310a,310b, and310cproviding the plurality of electrical paths may be applied to a signal wire for driving the display. In addition, according to embodiments of the inventive concept, the metal wires310a,310b, and310cproviding individual electrical paths to the top surface and side surfaces of one insulator may be provided, and thus, a width of the insulator may be relatively small when compared to a case in which one metal wire is provided on one insulator. Thus, stretch characteristics of the wire structure may be improved. In addition, to provide the plurality of electrical paths, when compared to a case in which a metal wire having a thin width is provided in plurality on a top surface of an insulator having a limited width, when metal wires, each of which has a wide width, are provided on top and side surfaces of an insulator, the metal wire may be improved in stability. Thus, driving stability of the wire structure may be improved.

FIG.5is a cross-sectional view of stretchable electronics according to embodiments of the inventive concept.

Referring toFIG.5, a trench T may be provided on a top surface of an insulator320a. The trench T of the insulator320amay extend along a direction in which the insulator320aextends. A metal wire310dcovering an inside wall and a bottom of the trench T may be provided on a top surface of the insulator320a. The metal wire310dmay extend from one side surface of the insulator320ato the other side surface of the insulator320athrough the top surface of the insulator320aand the inside wall and bottom of the trench T. The metal wire310dmay cover an entire surface of the insulator320aexcept for the bottom surface of the insulator320a. The insulator320amay not be exposed by the metal wire310d.

FIG.6is a cross-sectional view of stretchable electronics according to embodiments of the inventive concept.

InFIG.6, an insulator320aincluding the trench T described with reference toFIG.5may be provided. A conductive pattern311emay be provided in the trench T of the insulator320a. The trench T may be filled with a conductive pattern311e. The conductive pattern311emay be a wire including a metal. A bottom surface of the conductive pattern311emay be in contact with a bottom of the trench T. Side surfaces of the conductive pattern311emay be in contact with inside wall of the trench T. A level of the top surface of the conductive pattern311emay be the same as a level of the top surface of the insulator320a. That is, the top surface of the conductive pattern311eand the top surface of the insulator320amay be coplanar.

The metal wire310emay be provided on the insulator320a. The metal wire310emay cover the top surface and side surfaces of the insulator320aand the top surface of the conductive pattern311e. The metal wire310eand the conductive pattern311emay be in contact on the top surface of the insulator320a. The metal wire310emay extend from one side surface of the insulator320ato the other side surface of the insulator320athrough the top surface of the insulator320aand the top surface of the conductive pattern311e. The metal wire310emay cover the top surface and side surfaces of the insulator320aand the entire top surface of the conductive pattern311e. The insulator320aand the conductive pattern311emay not be exposed by the metal wire310e. Since the conductive pattern311ecorresponding to an additional wire is provided in the trench T of the insulator320a, the wire structure may be reduced in resistance.

FIG.7is a cross-sectional view of stretchable electronics according to embodiments of the inventive concept.

Referring toFIG.7, a plurality of trenches T may be provided in an insulator320b. The plurality of trenches T may extend along a direction in which the insulator320bextends. The plurality of trenches T may be spaced apart from each other in a direction perpendicular to the direction in which the insulator320bextends.

A metal wire310fmay conformally cover top and side surfaces of the insulator320band bottom and inside walls of the plurality of trenches T. The metal wire310fmay cover the entire surface except for the bottom surface of the insulator320b. The insulator320bmay not be exposed by the metal wire310f. As illustrated inFIG.7, a structure in which two trenches of the plurality of trenches T are provided in the insulator320bis illustrated, but an embodiment of the inventive concept is not limited thereto. For example, three or more trenches T may be provided.

FIG.8is a cross-sectional view of stretchable electronics according to embodiments of the inventive concept.

InFIG.8, an insulator320bincluding a plurality of trenches T described with reference toFIG.7may be provided. Conductive patterns311gmay be provided in the plurality of trenches T of the insulator320b, respectively. A level of a top surface of each of the conductive patterns311gmay be the same as a level of a top surface of the insulator320b. That is, the top surface of each of the conductive patterns311gand the top surface of the insulator320bmay be coplanar.

The metal wire310gmay be provided on the insulator320b. The metal wire310gmay cover the top surface and side surfaces of the insulator320band the top surface of the conductive patterns311g. The metal wire310gand the conductive patterns311gmay be in contact on the top surface of the insulator320b. The metal wire310gmay extend from one side surface of the insulator320bto the other side surface of the insulator320bthrough the top surface of the insulator320band the top surface of the conductive patterns311g. The metal wire310gmay cover the top surface and side surfaces of the insulator320band the entire top surface of the conductive patterns311g. The insulator320band the conductive patterns311gmay not be exposed by the metal wire310g. The conductive patterns311gcorresponding to the additional wires may be disposed in the trenches T of the insulator320bto reduce resistance of a wire structure. As illustrated inFIG.8, a structure in which two trenches of the plurality of trenches T are provided in the insulator320bis illustrated, but an embodiment of the inventive concept is not limited thereto. For example, three or more trenches T may be provided. Thus, three or more conductive patterns311gmay be provided.

In the stretchable electronics according to the embodiments illustrated inFIGS.2to8, the metal wire having a line width greater than that of the insulator may be applied to the wire structure. The metal wire applied to the existing stretchable electronics may be provided only on the top surface of the insulator, and a maximum width of the metal wire may be the width of the insulator. However, according to embodiments of the inventive concept, the metal wire may be provided not only on the top surface of the insulator, but also on the side surface of the insulator or inside the trench of the insulator, the metal wire having the line width greater than that of the insulator may be designed. Thus, since the line width of the metal wire increases compared to the width occupied by the wire structure, the resistance of the metal wire may be reduced. In addition, the width of the wire structure may be narrowed compared to the line width of the metal wire to relieve the stress applied to the wire structure when the stretchable electronics are expanded and contracted. Thus, stretch characteristics of the stretchable electronics may be improved. In the insulator in which the trench structure is provided according to the embodiments of the inventive concept illustrated inFIGS.5and7, the line width of the metal wire may increase as the number of trenches increases, and as a depth of the trench increases in a direction perpendicular to the substrate, the line width of the metal wire may increase. As the line width of the metal wire increases, the resistance of the metal wire may decrease.

FIGS.9to14are cross-sectional views illustrating a method for manufacturing stretchable electronics according to embodiments of the inventive concept.

Referring toFIG.9, an insulator1320may be provided on a top surface of a carrier substrate1000. The insulator1320may be the same material as the insulator described with reference toFIG.2. The carrier substrate1000may be a glass substrate.

The insulator1320may be patterned on the carrier substrate1000. The insulator1320may be patterned to include at least one bent part in a plan view. The patterning method may be one of a lithography method through reactive ion etching (ME), a lithography method using an insulator made of a photosensitive material, an inkjet printing method, and an imprint method. As illustrated inFIG.9, the insulator1320may be patterned to have a rectangular cross-sectional shape, but an embodiment of the inventive concept is not limited thereto. For example, the cross-sectional shape of the insulator1320may be patterned to include at least one trench. The trench may be patterned to extend along a direction in which the insulator1320extends. When a plurality of trenches is patterned on a top surface of the insulator1320, the plurality of trenches may be patterned to be spaced apart from each other in a direction perpendicular to the direction in which the insulator1320extends. In this case, the stretchable electronics described with reference toFIGS.5and7may be manufactured.

Referring toFIG.10, a wire structure1300may be formed by depositing a metal wire1310on a top surface and side surfaces of the insulator1320. The metal wire1310may cover a top surface of the carrier substrate1000on which the insulator1320is not provided and the entire top and side surfaces of the insulator1320. The carrier substrate1000and the insulator1320may not be exposed by the deposited metal wire1310. However, an embodiment of the inventive concept is not limited thereto, and a portion of the metal wire1310on the top surface of the insulator1320may be removed through an etching process. Thus, the metal wires1310deposited on the top surface of the insulator1320may be spaced apart from the metal wires1310deposited on the side surfaces of the insulator1320. In this case, the stretchable electronics described with reference toFIG.4may be manufactured. Hereinafter, the description will be continued based on the embodiment ofFIG.10. The metal wire1310may be deposited to conformally cover the insulator1320. Thus, the shape of the metal wire1310may be defined according to the shape of the insulator1320. A method of depositing the metal wire1310may be one of atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), or a solution process.

Referring toFIG.11, a process of separating the wire structure1300from the carrier substrate1000using a pick-up film2000may be performed. The pick-up film2000may be attached to a top surface of the wire structure1300. The pick-up film2000may be a film having adhesive properties. The pick-up film2000may be lift in a direction D1 perpendicular to the carrier substrate1000to separate the wire structure1300from the carrier substrate1000. The pick-up film2000may separate the insulator1320and the metal wire1310provided on the top surface and side surfaces of the insulator1320from the carrier substrate1000. After the process of separating the wire structure1300from the carrier substrate1000, the metal wire1311may remain on a top surface of the carrier substrate1000.

Referring toFIG.12, a process of disposing the wire structure1300on the insulating layer3000may be performed. The metal wire1310provided on the side surfaces of the insulator1320and the bottom surface of the insulator1320may be in contact with the top surface of the insulating layer3000. After the wire structure1300is disposed on the insulating layer3000, the pick-up film2000may be removed from the wire structure1300. In this case, the stretchable electronics described with reference toFIG.3may be manufactured. The insulating layer3000may be the substrate100(seeFIG.3) of the stretchable electronics. Hereinafter, the description will be continued based on the embodiment ofFIG.12. The insulating layer3000may be an elastomer. The insulating layer3000may be made of polydimethylsiloxane (PDMS) or polyurethane (PU). However, an embodiment of the inventive concept is not limited thereto.

Referring toFIG.13, a process of embedding the wire structure1300(seeFIG.11) in the insulating layer3000may be performed. The insulating layer3000may include the same material as the insulating layer3000described with reference toFIG.12. The insulating layer3000may cover the metal wire1310provided on the side surfaces of the insulator1320and the bottom surface of the insulator1320.

Referring toFIG.14, after the wire structure1300is embedded in the insulating layer3000, the pick-up film2000may be removed from the top surface of the insulating layer3000and the metal wire1310. As the pick-up film2000is removed, the top surface of the metal wire1310may be exposed.

FIGS.15and16are cross-sectional views illustrating a method for manufacturing stretchable electronics according to embodiments of the inventive concept.

Referring toFIG.15, a process of embedding a wire structure1300in an insulating layer3000may be performed on the results ofFIGS.9and10. The insulating layer3000may include the same material as the insulating layer3000described with reference toFIG.12. The insulating layer3000may cover the top surface of the metal wire1310deposited on the top surface of the carrier substrate1000and the metal wire1310deposited on the top surface and side surfaces of the insulator1320. The metal wire1310may not be exposed by the insulating layer3000.

Referring toFIG.16, the wire structure1300embedded in the insulating layer3000may be lifted in a direction D1 perpendicular to the carrier substrate1000so as to be separated from the carrier substrate1000. As the wire structure1300is separated from the carrier substrate1000, the bottom surface of the insulator1320may be exposed. After the wire structure1300is separated, the metal wire1311may remain on the top surface of the carrier substrate1000.

FIGS.17to20are cross-sectional views illustrating a method for manufacturing stretchable electronics according to embodiments of the inventive concept.

Referring toFIG.17, the process of forming a sacrificial layer4000on the carrier substrate1000may be further performed. The sacrificial layer4000may cover the entire top surface of the carrier substrate1000. The sacrificial layer4000may include a material etched in the same etching method as the insulator1320(seeFIG.18) formed in a process to be described later. Alternatively, the sacrificial layer4000may include an insulator1320(seeFIG.18) and a material having etch selectivity.

Referring toFIG.18, the insulator1320may be formed on a top surface of the sacrificial layer4000. A process of patterning the insulator1320may be the same as or similar to the process described with reference toFIG.9. When the insulator1320is patterned, the sacrificial layer4000may also be patterned. For example, the patterned insulator1320may be used as a mask pattern. Thus, a portion of the sacrificial layer4000disposed under the patterned insulator1320may remain.

Referring toFIG.19, in the patterning process, an under-cut of the sacrificial layer4000may be formed between the bottom surface of the insulator1320and the top surface of the carrier substrate1000. For example, when the sacrificial layer4000is patterned, the sacrificial layer4000may be over-etched between the carrier substrate1000and the insulator1320. As the under-cut4100of the sacrificial layer4000is formed, a width of the sacrificial layer4000may be less than that of the insulator1320.

Referring toFIG.20, after the sacrificial layer4000is patterned, the metal wire1310may be deposited on the insulator1320and the carrier substrate1000. The metal wire1310may be deposited using the same or similar method to the deposition method described with reference toFIG.10. As illustrated inFIG.20, as the under-cut4100of the sacrificial layer4000is present, a contact width between the metal wire1310deposited on the side surfaces of the insulator1320and the metal wire deposited on the top surface of the carrier substrate1000may be less than a thickness of each of the metal wires1310and1311. However, an embodiment of the inventive concept is not limited thereto, and the metal wire1310deposited on the side surfaces of the insulator1320may not be in contact with the metal wire1311deposited on the carrier substrate1000.

After the metal wire1310is deposited, a process that is the same as or similar to the manufacturing method described with reference toFIGS.11to16may be performed to separate the wire structure1300from the carrier substrate1000. In the process of separating the wire structure1300from the carrier substrate1000, the insulator1320and the sacrificial layer4000may be separated from each other, and the sacrificial layer4000may remain on the carrier substrate1000.

The sacrificial layer4000may be made of a material that is easily detachable from the insulator1320. Since the sacrificial layer4000may be disposed between the carrier substrate1000and the insulator1320, the metal wire1310deposited on the side surfaces of the insulator1320and the metal wire1311deposited on the top surface of the carrier substrate1000may be easily separated from each other. The separation of the wire structure1300from the carrier substrate1000may be facilitated. Therefore, the manufacturing of the stretchable electronics may be facilitated.

In the stretchable electronics according to the embodiments of the inventive concept, the metal wire may be provided not only on the top surface but also on the side surfaces of the insulator. That is, the metal wire having the line width greater than the width of the wire structure may be provided, and thus the resistance of the metal wire may be reduced. In addition, the width of the wire structure may be narrowed compared to the line width of the metal wire to relieve the stress applied to the wire structure when the stretchable electronics are expanded and contracted. That is, the stretchable electronics having the improved stretch characteristics may be provided.

Although the embodiment of the inventive concept is described with reference to the accompanying drawings, those with ordinary skill in the technical field of the inventive concept pertains will be understood that the present disclosure can be carried out in other specific forms without changing the technical idea or essential features. Therefore, the above-disclosed embodiments are to be considered illustrative and not restrictive.