Abstract:
A coil device may be capable of varying the gap of a coil so that several devices may be wirelessly charged simultaneously or a single device may be wirelessly charged with concentrated power. The coil device may include: a case having a reception space and varying a charging area upon a user&#39;s selection; and a coil part, having, in the reception space of the case, a coil body formed of a wound conductor having a predetermined length. A gap of the wound conductor of the coil body varies as the charging area of the case varies.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2013-0160325 filed on Dec. 20, 2013, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a coil device used for wireless power transmission, a wireless power transmitter and a wireless power receiver having the same. 
     Electric and electronic devices are devices operated with electricity as the energy source thereof. 
     In order to operate an electric or an electronic device, electrical power, the energy source necessary to operate the device, has to be supplied thereto from the outside, unless the device has self-power generation capability. 
     Accordingly, in order to receive power from the outside, it is necessary for the electric or the electronic device to be equipped with a power transmission means to deliver power from an external power utility facility to the device. 
     Incidentally, wireless charging technology refers to a technology that transmits power for charging a battery wirelessly, without using a power cord or a connector for charging. 
     Previously, wireless charging technology has seen limited use, commonly in devices such as electric toothbrushes, home cordless telephones, and power tools. 
     Recently, due to explosive growth in the smartphone market, wireless charging technology has rapidly become widespread. Smartphones allow users to enjoy rich content and multimedia services anywhere and at anytime, but they suffer from short usage times, due to limited battery capacity. 
     Among other methods, a common means of realizing wireless charging is to use magnetic inductance or magnetic resonance, which uses electromagnetic energy coupling generated in a coil wound a number of times, as disclosed in the patent document below. 
     This is implemented as a device which is operated based on Faraday&#39;s law of induction; in which an electromagnetic field generated by a coil in which alternating current (AC) power or high-frequency current is flowing induces electromotive force at the output terminal of an adjacent coil. When a typical mobile phone, a smartphone, a digital camera, a tablet PC, a monitor, a laptop computer or the like, having a wireless charging receiver module embedded therein, is placed on a charging surface of a wireless charger having a wireless charging transmitter module configured therein, an analog circuit, a power circuit, a control circuit, a rectifying circuit, a charging circuit and the like, associated with charging, may be operated so as to charge a battery embedded in the device. 
     However, such a wireless charger may have a relatively large volume, and thus it may be inconvenient to store and carry, and it may be difficult to wirelessly charge several devices simultaneously therewith. 
     SUMMARY 
     An aspect of the present disclosure may provide a coil device capable of varying the gap between turns of a coil so that several devices may be charged wirelessly and simultaneously or a single device may be wirelessly charged with concentrated power, and a wireless power transmitter and a wireless power receiver having the same. 
     According to an aspect of the present disclosure, a coil device may include: a case having a reception space and varying a charging area upon a user&#39;s selection; and a coil part, having, in the reception space of the case, a coil body formed of a wound conductor having a predetermined length, wherein a gap between turns of the wound conductor of the coil body varies as the charging area of the case varies. 
     The case may include a first case face having the reception space; and at least one second case face having a reception space and extending from the first case face so as to vary the area of the case. 
     The coil part may include: a first coil block accommodated in the reception space of the first case face and formed of a part of the coil body formed of the wound conductor having the predetermined length; and at least one second coil block accommodated in the reception space of the second case face, electrically connected to the first coil block, and formed of the other part of the coil body formed of the wound conductor having the predetermined length. 
     The second case face may be coupled to the first case face and may vary the area of the case in a folding manner. 
     The second case face may be coupled to the first case face and may vary the area of the case in a sliding manner. 
     Turns of the wound conductor of the at least one second coil block may be disposed between turns of the wound conductor of the first coil block when the area of the case is reduced. 
     According to another aspect of the present disclosure, a wireless power transmitter may include: a case having a reception space and varying a charging area upon a user&#39;s selection; a coil part, having, in the reception space of the case, a coil body formed of a wound conductor having a predetermined length, wherein a gap between turns of the wound conductor of the coil body varies as the charging area of the case varies such that the coil part wirelessly transmits power; and a power supplying unit supplying power to the coil part. 
     The power supplying unit may include: a power conversion unit converting alternating current power into direct current power having a predetermined level; a driving unit receiving the direct current power from the power conversion unit to wirelessly transmit the power using the coil part; and a control unit controlling electrical energy transmitted using the coil part depending on conditions of power supplied to the coil part. 
     According to another aspect of the present disclosure, a wireless power receiver may include: a case having a reception space and varying a charging area upon a user&#39;s selection; a coil part, having, in the reception space of the case, a coil body formed of a wound conductor having a predetermined length, wherein a gap between turns of the wound conductor of the coil body varies as the charging area of the case varies such that the coil part wirelessly receives power; and a connection unit transmitting the power received in the coil part to an external device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIGS. 1A and 1B  are views schematically illustrating a coil device according to an exemplary embodiment of the present disclosure; 
         FIGS. 2A and 2B  are views schematically illustrating a coil device according to another exemplary embodiment of the present disclosure; 
         FIGS. 3A ,  3 B,  4 A and  4 B are views schematically illustrating the configuration of a wireless power transmitter according to an exemplary embodiment of the present disclosure; and 
         FIGS. 5A through 5D  are views schematically illustrating a wireless power receiver according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as being 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 disclosure to those skilled in the art. In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
       FIGS. 1A and 1B  are views schematically illustrating a coil device according to an exemplary embodiment of the present disclosure. 
     Referring to  FIGS. 1A and 1B , the coil device  100  according to the exemplary embodiment may include a case  110  and a coil part  120 . 
     The case  110  may have a reception space therein and may include a first case face  111  and a second case face  112  to vary the area of a charging area. The charging area may be varied by varying the area of the case. Although only one first side  111  and only one second case face  112  are shown in the drawing, the numbers of the case faces are not limited to one. 
     In the reception space of the case  110 , the coil part  120  may be formed. The coil part  120  may have a coil body formed of a predetermined conductor. The coil body may be formed by bending the conductor into various shapes, such as spiral shape and a meandering line shape. Although in the drawings, the coil part  120  is depicted as having a spiral shape, the shape of the coil part  120  is not limited thereto and may have various shapes as necessary. 
     As shown  FIG. 1B , at least one second case face  112  may be extended from the first case face  111  so as to vary the area of the case, and accordingly, the gap between the conductors of the coil part  120  in the reception space of the case  110  may vary in width. 
     That is, the coil part  120  may include a first coil block  121  accommodated in the first case face  111 , and at least one second coil block  122  accommodated in the second case face  112 . The second coil block  122  is electrically connected to the first coil block  121 , and when the second case face  112  lies on, is stacked on or slides in the first case face  111 , the area of the case is reduced, so that the second coil block  122  and the first coil block  121  may form a single coil body. When the second case face  112  is extended from the first case face  111  such that the area of the case is enlarged, the second coil block  122  and the first coil block  121  may have respective coil bodies, which are predetermined. For example, as shown, the second coil block  122  may form a coil body having a spiral shape together with the first coil block  121 , each of the second coil block  122  and the first coil block  121  may form a coil body having a spiral shape. To this end, a coil connection part  123  having variable length may be formed between the second coil block  122  and the first coil block  121 . 
       FIGS. 2A and 2B  are views schematically illustrating a coil device according to another exemplary embodiment of the present disclosure. 
     Referring to  FIG. 2A , when the area of the case is reduced, the area of the case may be reduced in a folding manner, such as that a second case face  112  may be folded over or stacked on a first case face  111 . Further, the area of the case face may be enlarged when the second case face  112  is unfolded. To this end, a folding portion may be formed between the first case face  111  and the second case face  112 . 
     Referring to  FIG. 2B , the area of the case may be enlarged in a sliding manner such as that the second case face  112  may slide out of and be extended from the first case face  111 . Further, the second case face  112  may slide into the first case face, such that the area of the case may be reduced. 
       FIGS. 3A ,  3 B,  4 A and  4 B are views schematically illustrating the configuration of a wireless power transmitter according to an exemplary embodiment of the present disclosure. 
     Referring to  FIGS. 3A ,  3 B,  4 A and  4 B, the wireless power transmitter according to the exemplary embodiment may include a case  210 , a coil part  220 , and a power supplying unit  230 . 
     The case  210  and the coil part  220  of the wireless power transmitter  200  in this exemplary embodiment are identical to those described above with respect to the coil device  100 , and redundant descriptions will not be repeated hereinafter. When the area of the case  210  is enlarged, however, instead of widening the gap between turns of the coil of the coil part  220 , the area of the region in which the coil of the coil part  220  is located is enlarged accordingly, and devices A and B are placed on the first and second case faces  211  and  212  of the case  210 , respectively, such that power from the power supplying unit  230  is wirelessly transmitted to the at least two devices A and B, allowing for wireless charging thereof. When the area of the case  210  is reduced, the area of the region where the coil of the coil part  220  is located is also reduced or the gap of the coil is narrowed, such that power may be concentrated on the device A. Accordingly, the single device A may be wirelessly supplied with power to be rapidly charged. 
     The power supplying unit  230  may supply power to the devices A and B using the coil part  220  through magnetic inductance or magnetic resonance. When power is supplied though magnetic resonance, the power supplying unit  230  may include a power conversion unit  231 , a control unit  232 , and a driving unit  233 . 
     The power conversion unit  231  may convert an AC power into a predetermined DC power. 
     The driving unit  233  may drive the coil part  220  so that the DC power from the power conversion unit  231  is transmitted using the coil part through magnetic resonance. 
     The control unit  232  may detect the voltage applied to the coil part  220  and the current flowing in the coil part  220  so as to adjust the electrical energy. 
       FIGS. 5A through 5D  are views schematically illustrating a wireless power receiver according to an exemplary embodiment of the present disclosure. 
     Referring to  FIGS. 5A through 5D , the wireless power receiver according to the exemplary embodiment may include a case  310 , a coil part  320 , and a transmission unit  330 . 
     The case  310  and the coil part  320  of the wireless power receiver  300  in this exemplary embodiment is identical to those described above with respect to the coil device  100 , and redundant descriptions will not be repeated. When the area of the case  310  is enlarged, however, instead of widening the gap between turns of the coil  320 , the area of the region in which the coil of the coil part  220  is located is enlarged accordingly, such that a large amount of power may be wirelessly received when the wireless power receiver  300  wirelessly receives power from a power transmission device  1000  having a relatively large area. 
     On the contrary, when the area of the case  310  is reduced, the area of the region in which the coil of the coil part  220  is located is reduced accordingly, but the gap between turns of the coil is narrowed, so that the transmitted power may be concentrated. 
     If the case  310  is a case of a mobile phone, for example, the coil part  320  may consist of first and second coil blocks  321  and  322  on the front side  311  and rear side  312  of the case of the mobile phone, respectively, such that power is wirelessly received to be transmitted to the device A through the transmission unit  330 . 
     As set forth above, according to exemplary embodiment of the present disclosure, several devices may be charged wirelessly and simultaneously or a single device may be wirelessly charged with concentrated power. Further, the coil device is implemented in a folding manner or a sliding manner, such that an electronic device employing it may be convenient to carry and use. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the spirit and scope of the present disclosure as defined by the appended claims.