Patent Publication Number: US-2018047505-A1

Title: Electromagnetic Booster for Wireless Charging and Method of Manufacturing the Same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/433,424, filed Apr. 3, 2015, which is the U.S. national stage application of International Patent Application No. PCT/KR2013/008847, filed Oct. 4, 2013; which claims priority to Korean Patent Application No. 10-2012-0109900, filed Oct. 4, 2012; all of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     Embodiments of the present invention relate to an electromagnetic booster for wireless charging, and more specifically, to an electromagnetic booster for wireless charging, which has a magnetic part composed of a magnetic sheet and a metallic radiator layer, and a method of manufacturing the same. 
     Description of the Related Arts 
     A mobile terminal such as a cellular phone is driven by a battery, which can be recharged by its characteristic, and electrical energy is supplied to the battery of the mobile terminal using a separate charging device. Recently, as a wireless charging technology or non-contact charging technology has been developed, it has been utilized for various electromagnetic instruments. This wireless charging technology uses wireless power transmission and reception and is a system which enables the battery to be charged without connecting a separate charging connector to the terminal. 
     As illustrated in  FIG. 11 , a conventional booster for wireless charging is configured in a structure in which a magnetic layer  1  composed of a ferrite sintered material, a ferrite composite, a sendust sintered material, a sendust composite or the like, an adhesive layer A formed on the magnetic layer, and a metal coil  2  serving as a radiator and formed on the adhesive layer are laminated. In this conventional booster, since the metal coil  2  is formed on the magnetic layer  1 , malfunction which causes frequency interference, offsetting, extinction due to different operating frequencies can be generated. Furthermore, with regard to an adhesive layer A or an adhesive layer and an air layer located between the magnetic layer  1  and the metal coil  2 , a permeability rate can be reduced, a loss rate can be increased, and charging efficiency can be reduced. Also, the laminated structure acts as a drag on a slimming design of the wireless charging device. 
     SUMMARY OF THE INVENTION 
     An aspect of the embodiments of the present invention provides an electromagnetic booster for wireless charging, which can prevent malfunction due to frequency interference. 
     Another aspect of the embodiments of the present invention provides an electromagnetic booster for wireless charging that is capable of improving a bandwidth and a permeability rate and reducing a loss rate, and enables a wireless charging device to be slim in design. 
     Still another aspect of the embodiments of the present invention provides a method of manufacturing the electromagnetic booster for wireless charging. 
     According to an aspect of the embodiments of the present invention, there is provided an electromagnetic booster for wireless charging, comprising a magnetic material part having a magnetic sheet and a coil part disposed on the magnetic sheet, wherein the magnetic material sheet is composed of a first magnetic sheet member located at an edge portion and a second magnetic sheet member located in a center portion on the same plane, wherein the first magnetic sheet member and the second magnetic sheet member have different permeability rates from each other. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the first magnetic sheet member and the second magnetic sheet member may come into contact with each other or may be spaced apart from each other with an air gap formed therebetween. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may be composed of a first coil member and a second coil member disposed on each of surfaces of the first magnetic sheet member and of the second magnetic sheet member, and the first coil member and the second coil member may have a thin film coil-like shape. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that a concave part corresponding to a shape of the coil part may be formed on a surface of the magnetic sheet, and the coil part may be partially or entirely filled with the concave part in a depth direction of the concave part. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may be composed of a first coil member and a second coil member disposed on the first magnetic sheet member and the second magnetic sheet member by interposing an adhesive therebetween, and the first coil member and the second coil member may have a thin film coil-like shape. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the first magnetic sheet member and the second magnetic sheet member may have the same or different heights (thicknesses). 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic sheet may be made of a magnetic composition containing a magnetic material and a binder. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic material may be one element or an alloy composed of a combination of two or more elements selected from the group consisting of Fe, Ni, Co, Mn, Al, Zn, Cu, Ba, Ti, Sn, Sr, P, B, N, C, W, Cr, Bi, Li, Y and Cd, or ferrite. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic material may be a power having a particle size of 3 nm˜50 μm. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the binder may be one resin or a mixture of two or more resins selected from the group consisting of a polyvinyl alcohol (PVA) resin, a polysiloxane resin, an epoxy resin, an acrylate resin, an urethane resin, a polyimide resin and a polyamide resin. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic composition may contain the magnetic material of 10˜95 wt % and the binder of 5˜90 wt %. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic composition may further contain any one or two or more additives selected from the group consisting of a silane coupling agent, an antifoaming agent and a cross linking agent. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the magnetic composition may contain the additives in the range of less than 2 wt %. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may be made of Ag, Au, Cu or A. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may have a thickness (height) of 5 μm˜1 mm. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may have a pitch of 5˜500 μm. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging is characterized in that the coil part may further include a base film BF laminated thereon. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging may further include a base film BF laminated on a rear surface of the magnetic sheet. 
     Preferably, according to some embodiments of the present invention, the electromagnetic booster for wireless charging may include a magnetic sheet and a coil part disposed on the magnetic sheet. 
     According to another aspect of the embodiments of the present invention, there is provided a method of manufacturing an electromagnetic booster for wireless charging including a magnetic sheet and a coil part disposed on the magnetic sheet, the method including: forming the magnetic sheet with a first magnetic sheet member located at an edge portion and a second magnetic sheet member located in a center portion and having a different permeability rate from that of the first magnetic sheet member on the same plane; and laminating a coil part on the magnetic sheet. 
     Preferably, according to some embodiments of the present invention, the method is characterized in that the coil part may be formed by plating and etching processes of a metal, and a silk-screening printing process, a pattern coating process or a sputtering process. 
     Preferably, according to some embodiments of the present invention, the method is characterized in that the laminating of the coil part may include forming a concave part having a shape corresponding to the coil part by engraving a surface of the magnetic sheet; and forming the coil part by putting a metal thin film coil into the concave part. 
     Preferably, according to some embodiments of the present invention, the method is characterized in that the engraving may be performed using a laser exposure process, a dry etching process after masking, or a stepped pulley formation process with a difference in press between a corresponding area and a non-corresponding area of the engraving. 
     Advantageous effects of the electromagnetic booster for wireless charging according to the embodiments of the present invention are that: a wireless charging effect can be maximized; malfunction due to frequency interference can be prevented; it is appropriate for designs having various functions; a bandwidth and a permeability rate can be improved; a loss rate can be reduced; productivity can be improved thanks to a reduction in material and process costs; and a wireless charge device can be designed to be slimmer than before. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings: 
         FIG. 1  is a plan view of an electromagnetic booster having a magnetic sheet according to a first embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of an electromagnetic booster having a magnetic sheet according to a second embodiment of the present invention; 
         FIG. 4  is a cross-sectional view of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of an electromagnetic booster having a laminated structure according to a third embodiment of the present invention; 
         FIG. 6  is a cross-sectional view of an electromagnetic booster having a laminated structure according to a fourth embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of an electromagnetic booster having a laminated structure according to a fifth embodiment of the present invention; 
         FIG. 8  is a cross-sectional view of an electromagnetic booster having a laminated structure according to a sixth embodiment of the present invention; 
         FIG. 9  is a cross-sectional view of an electromagnetic booster having a laminated structure according to a seventh embodiment of the present invention; 
         FIG. 10  is a cross-sectional view of an electromagnetic booster having a laminated structure according to an eighth embodiment of the present invention; and 
         FIG. 11  is a plan view and a cross-sectional view of a conventional electromagnetic booster. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments according to the present invention will now be described more fully hereinafter with reference to the accompanying drawings. The exemplary embodiments of the present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Furthermore, when it is determined that specific descriptions regarding publicly known relevant functions or configurations may unnecessarily be beside main points of the present invention, the corresponding descriptions are omitted. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification. With regard to the elements which perform similar functions and operations, like numbers refer to like elements through the specification. 
     According to an embodiment of the present invention, an electromagnetic booster for wireless charging includes: a magnetic part having a magnetic sheet  10 ; and a coil part  20  disposed on the magnetic sheet  10 . 
     In the present embodiment of the invention, the magnetic sheet  10  is composed of a first magnetic sheet member  11  located at an edge portion and a second magnetic sheet member  12  located in a center portion on the same plane, and the first magnetic sheet member and the second magnetic sheet member have different permeability rates from each other. 
     According to the present embodiment of the invention, the magnetic sheet  10  is complexly composed of magnetic materials having different permeability rates from each other so that frequency interference, offsetting, extinction generated due to different operating frequencies can be prevented, thereby preventing malfunction from being generated. Furthermore, the magnetic sheet  10  can be efficiently used in wireless charge products for which various functions are required. 
     For example, the value of NFC operation frequency is about 13.56 MHz, and the value of wireless charging operation frequency is about 200˜300 KHz or 6.78 MHz when it is a magnetic induction type and is about 100˜200 KHz when it is a magnetic resonance type. 
     In the present embodiment of the invention, the first magnetic sheet member and the second magnetic sheet member may be disposed and configured to be come into contact with each other as shown in  FIG. 1  and  FIG. 2  illustrating a first embodiment of the present invention, or may be disposed and configured to be spaced apart from each other with an air gap  13  formed therebetween. 
     Also, the coil part  20  may have a thin film coil-like shape and may be composed of a first coil member  21  and a second coil member  22  disposed on each of surfaces of the first magnetic sheet member  11  and of the second magnetic sheet member  12  as shown in first and second embodiments. In plan views of  FIG. 1  and  FIG. 3 , non-explained reference numeral  23  refers to a conducting wire. 
     When the coil part  20  is formed on a surface of the magnetic sheet  10 , a concave part corresponding to a shape of the coil part  20  is formed on the surface of the magnetic sheet  10 , and particularly, it is preferable that the coil part  20  is partially or entirely filled with the concave part in a depth direction of the concave part. In a case where the in-mold type process is used, while a slimmer design can be realized, a thickness of the metal radiator layer  20  closely related to performance upon wireless charging can be maximized. Also, since the metal radiator layer  20  can be formed to be thick as the magnetic sheet  10 , a wireless charging effect can be maximized. Also, material and process costs of the coil part as well as those of the magnetic sheet can be reduced, and the slimmer design of the electromagnetic booster can be achieved. In the conventional electromagnetic booster, a thickness of the radiator coil is about 0.35˜1.0 mm, whereas in the electromagnetic booster according to the embodiments of the present invention, a thickness of the coil part  20  may be produced in various ranges of an unit. 
     Also, in the electromagnetic booster according to some embodiments of the present invention, the coil part  20  may be disposed on the magnetic sheet  10  by interposing an adhesive therebetween as shown in the embodiments of  FIG. 5 to 10 . 
     Also, in the electromagnetic booster according to some embodiments of the present invention, the first magnetic sheet member  11  and the second magnetic sheet member  12  may have the same or different heights (thicknesses). For example, as shown in the fourth and seventh embodiments, the height of the first magnetic sheet member  11  may be formed higher than that of the second magnetic sheet member  12 . Alternately, as shown in the fifth and eighth embodiments, the height of the first magnetic sheet member  11  may be formed lower than that of the second magnetic sheet member  12 . 
     In the embodiments of the present invention, the magnetic sheet is made of a magnetic composition containing a magnetic material and a binder. 
     In the magnetic composition according to the embodiments of the present invention, the magnetic material may be one element or an alloy of a combination of two or more elements selected from the group consisting of Fe, Ni, Co, Mn, Al, Zn, Cu, Ba, Ti, Sn, Sr, P, B, N, C, W, Cr, Bi, Li, Y, Cd and the like, or ferrite, and may be in a powder state in a particle size of 3 nm˜50 μm. 
     Also, in the magnetic composition, the binder is one resin or a mixture of two or more resins selected from the group consisting of a polyvinyl alcohol (PVA) resin, a polysiloxane resin, an epoxy resin, an acrylate resin, a urethane resin, a polyimide resin and a polyamide resin. 
     In the magnetic composition, with regard to a mixture ratio of the magnetic material and the binder, the magnetic material of 10˜95 wt % and the binder of 5˜90 wt % may be mixed. 
     Furthermore, the magnetic composition may contain other general additives well known in the relevant field in the amount of less than 2 wt %. Examples of the additives are a silane coupling agent, an antifoaming agent, a cross-linking agent and the like. 
     In the electromagnetic booster according to the embodiments of the present invention, the coil part  20  may be made of a metal such as Ag, Au, Cu, Al and the like, a thickness of the coil part  20  may range from 5 μm to 1 mm, a pitch thereof may range from 5 to 500 μm. Here, the pitch means a distance between spiral coils which form the coil part  20 , namely, a spaced distance among adjacent spiral coils. 
     The electromagnetic booster according the embodiments of the present invention may be commercialized by laminating a base film  30  on an assembly of the magnetic sheet  10  and the coil part  20 . The base film may be laminated on the coil part  20  or may be laminated on a rear surface (a surface on which the coil part  20  is not formed) of the magnetic sheet  10 . In an example illustrated, although the base film  30  is composed a film body  32  and an adhesive layer  31  formed thereon, the base film  30  may be composed of only the film body without the adhesive layer by using an adhesive property which the film itself has. 
     Hereinafter, a method of manufacturing the electromagnetic booster according to the embodiments of the present invention will be explained. 
     The electromagnetic booster according to the embodiments of the present invention may be manufactured by forming the magnetic sheet with the first magnetic sheet member located at the edge portion and the second magnetic sheet member located in an center portion and having the different permeability rate from that of the first magnetic sheet member on the same plane, and thereafter, laminating the coil part on the magnetic sheet. 
     Here, the coil part may be formed using a plating process and an etching process of a metal, a silkscreen printing process, a pattern coating process or a sputtering process. 
     Also, the laminating of the coil part may include forming a concave part having a shape corresponding to the coil part by engraving a surface of the magnetic sheet, and thereafter, forming the coil part by putting a metal thin film coil into the concave part. 
     The engraving of the magnetic sheet may be performed using a laser exposure process, a dry etching process after masking, a stepped pulley formation process with a difference in press between a corresponding area and an irrelevant are of the engraving, and the like. 
     As previously described, in the detailed description of the invention, having described the detailed exemplary embodiments of the invention, it should be apparent that modifications and variations can be made by persons skilled without deviating from the spirit or scope of the invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims and their equivalents.