Patent Publication Number: US-2017352951-A1

Title: Coil-type loop antenna for mobile device

Description:
TECHNICAL FIELD 
     The present disclosure relates to a mobile device with a coil-type loop antenna installed in it, and more particularly, to a coil-type loop antenna for a mobile device, which is provided around a receiver or speaker with a permanent magnet of the mobile device installed therein, so that propagation interference caused by characteristics of the material of a case may be minimized, antenna transmission and reception efficiency may be increased by use of a magnetic field of the permanent magnet, and a product may be miniaturized due to a decrease in the volume required for antenna installation. 
     BACKGROUND ART 
     In general, a mobile device is a kind of terminal that a user uses for mobile communication, which is capable of exchanging signals such as voice, images, and data with the other party during roaming. 
     In addition to actual communication, the mobile device is equipped with additional functions such as e-book, MP3, camera, recorder, scanner, multimedia play, and gaming. With a tablet computer function added, an advanced device serving as a smartphone has recently been commercialized. 
     Further, as the mobile device is equipped with a Near Field Communication (NFC) function, the mobile device finds its applications for a contact-free credit card, electronic payment, identification, and so on. Since NFC uses a radio signal in a frequency band as defined by a specific standard, NFC requires an antenna which is typically a loop antenna pattern. 
     NFC is a short-range wireless communication technology for data communication in a predetermined frequency band at a short distance. NFC is characterized by less power consumption and compatibility with contact-free Radio Frequency IDentification (RFID). NFC schemes are classified into active communication schemes and passive communication schemes. 
     In NFC, a history or information about each product or item is acquired by reading information written in the memory of a tag attached to the product or item in a read mode, or bi-directional communication is conducted in a Peer-to-Peer (P2P) mode, for electronic payment or one-to-one communication. For NFC, therefore, electronic circuits and antennas of a transmitter and a receiver need to be configured to recognize each other and operate by exchanging signals in a radio frequency of a specific frequency band. 
     To transmit and receive NFC signals, a built-in antenna connected to the main board of the mobile device is installed inside the mobile device. To minimize signal interference with internal electronic parts of the mobile device, the antenna is disposed in a rear case, apart from the internal electronic parts. 
     In regards to a conventional loop antenna installed in a rear case, since an antenna installation space needs to be secured in the rear case, the space is spared in consideration of a required volume for the antenna during manufacture of the case, which makes product miniaturization difficult. 
     Moreover, as the case of a mobile device has recently been fabricated of a metal, signal interference occurs to a built-in loop antenna installed in a rear cover of the mobile device, resulting in a decrease in the transmission and reception efficiency of signals. That is, when the magnetic field of the loop antenna is formed, the metal interferes with the magnetic field formation, thereby decreasing the accurate radiation efficiency of NFC signals. 
     In addition, since the conventional loop antenna has a structure in which an antenna is disposed inside the case, and requires installation of various parts for the antenna, it suffers from the increase of production cost. 
     DISCLOSURE 
     Technical Problem 
     An aspect of the present disclosure devised to solve the conventional problem is to provide a coil-type loop antenna for a mobile device, which is installed by winding a coil around a speaker of the mobile device, so that transmission and reception efficiency may be increased by means of a permanent magnet of the speaker, and a volume required for antenna installation may be reduced, thereby making product miniaturization possible. 
     It will be appreciated by persons skilled in the art that the objects that could be achieved with the present disclosure are not limited to what has been particularly described hereinabove and the above and other objects that the present disclosure could achieve will be more clearly understood from the following detailed description. 
     Technical Solution 
     In an aspect of the present disclosure, a coil-type loop antenna for a mobile device is installed in the mobile device, and includes an antenna coil wound around an outer surface of a housing of a permanent magnet structure having a permanent magnet installed therein. 
     The permanent magnet structure may be a speaker. 
     The permanent magnet structure may be a receiver. 
     The outer surface of the housing may be an outer circumferential surface of the housing, and the antenna coil may be wound around the permanent magnet structure. 
     The outer surface of the housing may be a top surface of the housing, and the antenna coil may be wound on a top surface of the permanent magnet structure. 
     The outer surface of the housing may be a bottom surface of the housing, and the antenna coil may be wound on a bottom surface of the permanent magnet structure. 
     The outer surface of the housing may be an outer circumferential surface of the housing, the antenna coil may be wound a plurality of times around a part of the outer circumferential surface of the housing, and a magnetic field inductor may be provided around the remaining part of the outer circumferential surface of the housing. 
     The outer surface of the housing may be an outer circumferential surface of the housing, the antenna coil may be wound around the permanent magnet structure, and a magnetic field inductor may be disposed between the outer circumferential surface of the housing and the antenna coil, surrounding a part of the outer circumferential surface of the housing. 
     The magnetic field inductor may be formed of a metal. 
     The magnetic field inductor may be formed of ferrite. 
     The magnetic field inductor may be formed of a magnetic rubber. 
     Details of other embodiments lie within the detailed description of the present disclosure and the drawings. 
     Advantageous Effects 
     According to a coil-type loop antenna for a mobile device according to an embodiment of the present disclosure, the antenna is installed outside a speaker of the mobile device. As the antenna is configured using a magnetic field of a permanent magnet of the speaker, a required volume for the antenna is reduced, thereby enabling product miniaturization. 
     As the coil-type loop antenna for a mobile device according to the present disclosure is configured to transmit and receive Near Field Communication (NFC) signals by use of the magnetic field of the permanent magnet installed in the speaker, propagation interference of a metal case may be minimized. The resulting increase of antenna reception efficiency may lead to performance improvement. 
     Particularly, even though the case is formed of a metal causing interference to transmission and reception of the loop antenna, the effect of the interference may be minimized by the magnetic field of the permanent magnet of the speaker. Accordingly, transmission and reception performance of NFC signals may be maintained. 
     Further, in a coil-type loop antenna for a mobile device according to an embodiment of the present disclosure, since a magnetic field generated from an antenna coil wound around a speaker serves as an antenna, the installation space of the speaker may be utilized. The decrease of a volume required for the antenna may lead to saving the space of the mobile device, thereby enabling product miniaturization. 
     It will be appreciated by persons skilled in the art that the effects that can be achieved with the present disclosure are not limited to what has been particularly described hereinabove and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a use state diagram illustrating an installation state of a coil-type loop antenna for a mobile device according to an embodiment of the present disclosure. 
         FIG. 2  is a perspective view illustrating a main part in which the coil-type loop antenna for a mobile device illustrated in  FIG. 1  is installed. 
         FIG. 3  is a front view illustrating an operation state of the coil-type loop antenna for a mobile device, illustrated in  FIG. 1 . 
         FIG. 4  is a perspective view illustrating the operation state of the coil-type loop antenna for a mobile device, illustrated in  FIG. 1 . 
         FIG. 5  is a sectional view illustrating the operation state of the coil-type loop antenna for a mobile device, illustrated in  FIG. 1 . 
         FIG. 6  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to another embodiment of the present disclosure. 
         FIG. 7  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to a third embodiment of the present disclosure. 
         FIG. 8  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to a fourth embodiment of the present disclosure. 
         FIG. 9  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to a fifth embodiment of the present disclosure. 
     
    
    
       
     
       
         
           
               
             
               
                   
               
               
                 &lt;Description of Reference Numerals for Main Components in 
               
               
                 the Drawings&gt; 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                  1: mobile device 
                  10: case 
               
               
                   
                  20: speaker 
                  21: housing 
               
               
                   
                  22: permanent magnet 
                  23: speaker coil 
               
               
                   
                  24: diaphragm 
                  25: gasket 
               
               
                   
                 100: loop antenna 
                 110: antenna coil 
               
               
                   
                 111: coil connector 
                 120: magnetic field inductor 
               
               
                   
                   
               
            
           
         
       
     
     MODE FOR CARRYING OUT THE INVENTION 
     The objects and effects of the present disclosure, and technical configurations to achieve them will become apparent upon examination of the following embodiments of the present disclosure described with reference to the attached drawings. A detailed description of a generally known function or structure of the present disclosure will be avoided lest it should obscure the subject matter of the present disclosure. In addition, although the terms used in the present disclosure are defined in consideration of their structures, roles, and functions in the present disclosure, the terms may be changed according to the intention of a user or an operator, or customs. 
     However, the present disclosure may be implemented in various ways, not limited to the following embodiments. The embodiments of the present disclosure are provided to assist in a comprehensive understanding of the scope and spirit of the present disclosure, and the present disclosure is defined only by the appended claims and their equivalents. Therefore, the definition should be made based on the whole contents of the specification. 
     Now, a detailed description will be given of a coil-type loop antenna for a mobile device according to an embodiment of the present disclosure. 
       FIG. 1  is a use state diagram illustrating an installation state of a coil-type loop antenna for a mobile device according to an embodiment of the present disclosure,  FIG. 2  is a perspective view illustrating a main part in which the coil-type loop antenna for a mobile device illustrated in  FIG. 1  is installed,  FIG. 3  is a front view illustrating an operation state of the coil-type loop antenna for a mobile device illustrated in  FIG. 1 ,  FIG. 4  is a perspective view illustrating the operation state of the coil-type loop antenna for a mobile device illustrated in  FIG. 1 , and  FIG. 5  is a sectional view illustrating the operation state of the coil-type loop antenna for a mobile device illustrated in  FIG. 1 . 
     Referring to  FIGS. 1 and 5 , a coil-type loop antenna  100  for a mobile device according to an embodiment of the present disclosure is installed around a speaker  20  having a permanent magnet  22 , among parts mounted in a mobile device  1 , so as to transmit and receive signals through mutual resonation with Near Field Communication (NFC) signals. 
     The speaker  20  is given as an exemplary permanent magnet structure with the permanent magnet  22  installed therein, for the convenience of description. The coil-type loop antenna  100  for a mobile device is applicable to any part having the permanent magnet  22  installed therein in the mobile device  1 . Particularly, it is apparent to those skilled in the art that a configuration in which the coil-type loop antenna  100  for a mobile device is installed in a receiver with the permanent magnet  22  installed therein may also fall within the scope of the present disclosure. 
     In other words, the coil-type loop antenna  100  for a mobile device may be installed in the receiver. 
     In the speaker  20  installed in the mobile device  1 , a housing  21  is installed in a voice output part in a portion of a case  10 . The permanent magnet  22  around which a speaker coil  23  is wound to resonate a diaphragm during voice output is mounted inside the housing  21 . A gasket  25  is installed in the other portion of the housing  21 , so that voice generated by resonation of the diaphragm  24  may pass through the gasket  25  to be output to the outside and the interior may be protected. 
     In this speaker  20 , when a signal corresponding to voice is applied to the speaker coil  23  in the area of a magnetic field generated from the permanent magnet  22 , the diaphragm  24  may be vibrated, and the resulting output voice may be output to the outside through the gasket  25 . Thus, a user may recognize the voice. 
     As described above, the permanent magnet  22  mounted in the speaker  20  forms a magnetic field, for mutual resonation between the speaker coil  23  and a signal to vibrate the diaphragm  24 . Therefore, in the case where the coil-type loop antenna  100  is installed around the housing  21 , if a magnetic field of the coil-type loop antenna  200  is generated within the magnetic field formed by the permanent magnet  22 , the magnetic fields are added up, thereby increasing transmission and reception efficiency. 
     That is, as the coil-type loop antenna  100  is located within the magnetic field of the permanent magnet  22 , the strength of a magnetic field generated during generation of a signal in a specific frequency band mutually resonating with an NFC signal is increased. Therefore, the transmission and reception efficiency of the coil-type loop antenna  100  may be increased. 
     Particularly, if the case  10  of the mobile device  1  is fabricated of a metal, installation of the loop antenna inside the case  10  causes signal interference to the case  10  during transmission and reception of NFC signals in a specific frequency band, thereby decreasing transmission and reception efficiency. Accordingly, as the coil-type loop antenna  100  is wound in the form of a coil around the outer surface of the speaker  20  with the permanent magnet  22  installed therein, a magnetic field is generated from an antenna coil  110  within a magnetic field generated from the permanent magnet  22 . The resulting maximization of the transmission and reception efficiency of NFC signals may lead to minimal signal interference with the metal case  10 . 
     The coil-type loop antenna  100  for a mobile device according to the embodiment of the present disclosure includes the antenna coil  110  wound a plurality of times around the housing  21 . 
     As the antenna coil  110  is wound around the housing  21  with the permanent magnet  22  installed therein, when power is supplied to the antenna coil  110 , the antenna coil  110  generates a magnetic field for NFC transmission and reception within the magnetic field of the permanent magnet  22 , and thus the strength of the magnetic field is increased, thereby minimizing the effect of external interference and increasing the transmission and reception efficiency of NFC signals. 
     A frequency may be controlled according to the number of windings of the antenna coil  110  around the housing  21  of the speaker  20 . Therefore, once a user-desired specific frequency band is determined, the number of windings of the antenna coil  110  may be determined in consideration of the size of a magnetic field depending on the diameter of the housing  21  and the strength of a magnetic field generated from the permanent magnet  22 . 
     Particularly, the magnetic field generated from the antenna coil  110  serves as a loop antenna for transmitting and receiving NFC signals. Therefore, the number of windings is preferably controlled according to a specific frequency band that may mutually resonate with NFC signals. 
     Since the coil-type loop antenna  100  is configured by winding the antenna coil  110  around the housing  21  having the permanent magnet  22  installed therein, the coil-type loop antenna  100  is easily installed and has a simple structure. In addition, since a mutually resonating frequency band may be controlled according to the number of windings of the antenna coil  110 , the application range of the coil-type loop antenna  100  may be extended. 
     Further, coil connectors  111  may be provided at both ends of the antenna coil  110 , for connection to a control circuit (not shown) installed in the case  10  of the mobile device  1 . The coil connectors  111  may be installed to electrically connect the antenna coil  110  to the control circuit, for power supply during transmission and reception of NFC signals and transfer of signals transmitted and received by mutual resonation. 
       FIG. 6  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to another embodiment of the present disclosure. 
     Referring to  FIG. 6 , the coil-type loop antenna  100  for a mobile device according to another embodiment of the present disclosure includes the antenna coil  110  wound a plurality of times on a top surface of the gasket  25 , defined as a direction in which the gasket  25  of the housing  21  is installed. 
     The antenna coil  110  is wound on a top surface of the housing  21  having the permanent magnet  22  installed therein to a size predetermined according to the shape of a magnetic field of the permanent magnet  22  so as to amplify the magnetic field of the permanent magnet  22 . As the antenna coil  110  is wound on the top surface of the housing  21 , when power is supplied to the antenna coil  110 , the antenna coil  110  generates an NFC transmission and reception magnetic field within the magnetic field of the permanent magnet  22 . The resulting increased magnetic field strength leads to the increase of NFC transmission and reception efficiency, while minimizing the effect of external interference. 
     The coil connectors  111  may be provided at both ends of the antenna coil  110 , for connection to the control circuit installed in the case  10  of the mobile device  1 . The coil connectors  111  may be installed to electrically connect the antenna coil  110  to the control circuit, for power supply during transmission and reception of NFC signals and transfer of signals transmitted and received by mutual resonation. 
       FIG. 7  is a sectional view illustrating an installation state of a coil-type loop antenna for a mobile device according to a third embodiment of the present disclosure. 
     Referring to  FIG. 7 , the coil-type loop antenna  100  for a mobile device according to the third embodiment of the present disclosure includes the antenna coil  110  wound a plurality of times on a bottom surface of the housing  21 , defined as a direction opposite to the direction in which the gasket of the housing  21  is installed. 
     The antenna coil  110  is wound on the bottom surface of the housing  21  to a size predetermined according to the shape of a magnetic field of the permanent magnet  22  so as to amplify the magnetic field of the permanent magnet  22 . As the antenna coil  110  is wound on the bottom surface of the housing  21 , when power is supplied to the antenna coil  110 , the antenna coil  110  generates an NFC transmission and reception magnetic field within the magnetic field of the permanent magnet  22 . The resulting increased magnetic field strength leads to the increase of NFC transmission and reception efficiency, while minimizing the effect of external interference. 
     The coil connectors  111  may be provided at both ends of the antenna coil  110 , for connection to the control circuit installed in the case  10  of the mobile device  1 . The coil connectors  111  may be installed to electrically connect the antenna coil  110  to the control circuit, for power supply during transmission and reception of NFC signals and transfer of signals transmitted and received by mutual resonation. 
       FIG. 8  is a sectional view illustrating an installed state of a coil-type loop antenna for a mobile device according to a fourth embodiment of the present disclosure. 
     Referring to  FIG. 8 , the coil-type loop antenna  100  for a mobile device according to the fourth embodiment of the present disclosure includes the antenna coil  110  and a magnetic field inductor  120 , each of which surrounds a part of the housing  21 . 
     The antenna coil  110  is wound around a part of an outer surface of the housing  21 , upward from the center. As power is supplied to the antenna coil  10  around the housing  21 , induction of the magnetic field of the permanent magnet  22  installed inside the housing  21  through the magnetic field inductor  120  leads to generation of a magnetic field, thereby increasing NFC transmission and reception efficiency. 
     The coil connectors  111  may be provided at both ends of the antenna coil  110 , for connection to the control circuit installed in the case  10  of the mobile device  1 . The coil connectors  111  may be installed to electrically connect the antenna coil  110  to the control circuit, for power supply during transmission and reception of NFC signals and transfer of signals transmitted and received by mutual resonation. 
     The magnetic field inductor  120  surrounds the remaining part of the outer surface of the housing  21 , downward from the center, apart from the antenna coil  110  in order to induce the magnetic field generated from the antenna coil  110 . To avoid overlap with the antenna coil  110 , for induction of the magnetic field generated from the antenna coil  110 , the magnetic field inductor  120  is provided downward from the center on a partial outer surface of the housing except the surface surrounded by the antenna coil  110 . Since the magnetic field inductor  120  is formed of a material that increases the generation efficiency of a magnetic field produced by current applied to the antenna coil  110 , the magnetic field inductor  120  may increase the generation efficiency of the magnetic field. 
     The magnetic field inductor  120  is formed of a material that may induce a magnetic field when power is supplied to the antenna coil  110 . Preferably, the magnetic field inductor  120  may be formed of one selected from a metal, ferrite being a magnetic material, and a magnetic rubber being an absorption material that has a magnetic force and absorbs an impact. 
     That is, the antenna coil  110  is provided upward from the center around the housing  21  and the magnetic field inductor  120  is provided downward from the center around the housing  21 , so that the antenna coil  110  and the magnetic field inductor  120  may not overlap with each other. As the antenna coil  110  and the magnetic field inductor  120  are installed without overlap in predetermined areas of the outer surface of the housing  21 , the magnetic field generated from the antenna coil  110  may be induced and a magnetic field induction direction may be set. 
       FIG. 9  is a sectional view illustrating an installed state of a coil-type loop antenna for a mobile device according to a fifth embodiment of the present disclosure. 
     Referring to  FIG. 9 , the coil-type loop antenna  100  for a mobile device according to the fifth embodiment of the present disclosure includes the magnetic field inductor  120  and the antenna coil  110  which ae wound around the housing  21 . 
     The antenna coil  110  is wound a plurality of times around the housing  21 . As power is supplied to the antenna coil  10  around the housing  21 , induction of the magnetic field of the permanent magnet  22  installed inside the housing  21  through the magnetic field inductor  120  leads to generation of a magnetic field, thereby increasing NFC transmission and reception efficiency. 
     Further, the coil connectors  111  may be provided at both ends of the antenna coil  110 , for connection to the control circuit installed in the case  10  of the mobile device  1 . The coil connectors  111  may be installed to electrically connect the antenna coil  110  to the control circuit, for power supply during transmission and reception of NFC signals and transfer of signals transmitted and received by mutual resonation. 
     The magnetic field inductor  120  is disposed between the outer surface of the housing  21  and the antenna coil  110 , surrounding a part of the outer surface of the housing  21 . Since the magnetic field inductor  120  is formed of a material that increases the generation efficiency of a magnetic field generated by current applied to the antenna coil  110 , the magnetic field inductor  120  may increases the generation efficiency of the magnetic field. 
     The magnetic field inductor  120  is formed of a material that may induce a magnetic field when power is supplied to the antenna coil  110 . Preferably, the magnetic field inductor  120  may be formed of one selected from a metal, ferrite being a magnetic material, and magnetic rubber being an absorption material that has a magnetic force and absorbs an impact. 
     That is, the magnetic field inductor  120  surrounds the outer surface of the housing  21  and the antenna coil  110  is wound a plurality of times around the magnetic field inductor  120 , so that the antenna coil  110  and the magnetic field inductor  120  may overlap with each other on the outer surface of the housing  21 . 
     As the antenna coil  110  and the magnetic field inductor  120  are sequentially installed around the housing  21 , overlapping with each other, the magnetic field generated from the antenna coil  110  may be induced and the generation efficiency of the magnetic field may be increased. 
     Preferred embodiments of the present disclosure have been disclosed in the specification and drawings. While specific terms are used, they are used in their general meaning to describe the present disclosure and assist understanding of the present disclosure, not limiting the scope of the present disclosure. It will be apparent to those skilled in the art that other modification examples than the disclosed embodiments can be implemented without departing from the scope and spirit of the present disclosure.