Wireless power receiver and method of manufacturing the same

A wireless power receiver can include a magnetic substrate and a coil configured to wirelessly receive power. The coil can be formed as a conductive layer on the magnetic substrate. A connecting unit can be disposed in a receiving space of the magnetic substrate and can be connected to the coil unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C §119 of Korean Patent Application Nos. 10-2012-0029987, filed Mar. 23, 2012, and 10-2012-0079004, filed Jul. 19, 2012, which are hereby incorporated by reference in their entirety.

BACKGROUND

The embodiment relates to a wireless power receiver and a method of manufacturing the same. In more particular, the embodiment relates to a wireless power receiver used for wireless power transmission or an antenna to reduce a thickness of the wireless power receiver and to simplify the manufacturing process thereof and a method of manufacturing the same.

A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method of transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. The electromagnetic induction refers to the generation of an electric current through induction of a voltage when a magnetic field is changed around a conductor. The electromagnetic induction scheme has been successfully commercialized for electronic appliances having small sizes, but represents a problem in that the transmission distance of power is too short.

Besides the electromagnetic induction scheme, the long-distance transmission using the resonance and the short-wavelength radio frequency has been suggested as the wireless energy transfer scheme.

However, in general, a wireless power receiver disposed in a terminal has a thick thickness and the manufacturing process thereof is complicated.

BRIEF SUMMARY

An embodiment provides a method capable of remarkably reducing a thickness of a wireless power receiver by directly disposing a coil unit on a top surface of a magnetic substrate.

An embodiment provides a method capable of ensuring high power transmission efficiency and enabling communication with external devices by directly disposing a coil unit and a near field communication antenna on a top surface of a magnetic substrate.

An embodiment provides a method capable of simplifying the manufacturing process for a wireless power receiver by directly disposing a coil unit on a magnetic substrate.

An embodiment provides a method capable of remarkably reducing a thickness of a wireless power receiver by disposing a coil unit inside a magnetic substrate.

An embodiment provides a method capable of ensuring high power transmission efficiency and enabling communication with external devices by disposing a coil unit inside a magnetic substrate and a near field communication antenna on a magnetic substrate.

An embodiment provides a method capable of simplifying the manufacturing process for a wireless power receiver by disposing a coil unit inside a magnetic substrate.

A wireless power receiver according to one embodiment includes a magnetic substrate and a coil configured to wirelessly receive power, wherein the coil is formed as a conductive layer on the magnetic substrate.

A wireless power receiver according to one embodiment includes a magnetic substrate and a coil a coil configured to wirelessly receive power, wherein the coil is formed as a conductive layer at the magnetic substrate, wherein a part of the coil is disposed inside the magnetic substrate.

A method of manufacturing a wireless power receiver for wirelessly receiving power according to one embodiment includes forming a conductor on a protective film, forming a conductive pattern by etching the conductor, connecting a connecting unit to be connected to an external circuit to a connection terminal of the conductive pattern, obtaining a magnetic substrate having a receiving space of a predetermined shape corresponding to the connecting unit and disposing the magnetic substrate on the conductive pattern while positioning the connecting unit in the receiving space.

According to one embodiment, the thickness of the wireless power receiver can be remarkably reduced by directly disposing the coil unit on a top surface of the magnetic substrate. According to one embodiment, the high power transmission efficiency can be ensured and communication with external devices can be enabled by directly disposing the coil unit and the near field communication antenna on the top surface of the magnetic substrate.

According to one embodiment, the manufacturing process for the wireless power receiver can be simplified by directly disposing the coil unit on the magnetic substrate only through laminating and etching processes.

According to one embodiment, the thickness of the wireless power receiver can be remarkably reduced by forming the conductive pattern inside the magnetic substrate.

According to one embodiment, the high power transmission efficiency can be ensured by forming the conductive pattern inside the magnetic substrate and the communication with external devices can be enabled by using the near field communication antenna.

According to one embodiment, the connecting unit is disposed in the receiving space of the magnetic substrate so that the thickness of the wireless power receiver can be remarkably reduced as much as the thickness of the connecting unit.

According to one embodiment, a tape substrate is used as the connecting unit so that the overall size of the wireless power receiver can be reduced.

According to one embodiment, a lead frame is used as the connecting unit, so the wiring layer included in the connecting unit can be protected from the heat, external moisture or impact and the mass production can be realized.

According to one embodiment, the magnetic field directed to the outside can be changed into the coil unit due to the conductive pattern formed in the magnetic substrate, so the power transmission efficiency can be improved, at the same time, the amount of the magnetic field leaked to the outside can be reduced so that the bad influence of the magnetic field exerted to the human body can be diminished.

According to one embodiment, the wireless power receiver can be manufactured only through the processes of forming the pattern groove and inserting the coil unit, so that the manufacturing process can be simplified.

Other various effects of the embodiments will be disclosed directly or indirectly in the detailed description of the embodiments.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described in detail with reference to accompanying drawings so that those skilled in the art can easily work with the embodiments.

Hereinafter, “conductive pattern” refers to the shape of a conductive layer and may be used to refer to a structure formed by a patterning process. “conductive layer” may be used interchangeably with “conductive pattern” and refers to a structure formed by methods including patterning, etching, deposing, selective plating, and the like.

FIG. 1is a perspective view illustrating a wireless power receiver1000according to the first embodiment,FIG. 2is a plan view illustrating the wireless power receiver1000according to the first embodiment andFIG. 3is a sectional view taken along line A-A′ of a connecting unit300of the wireless power receiver1000shown inFIG. 2.

Referring toFIGS. 1 to 3, the wireless power receiver1000may include a magnetic substrate100, a coil unit200and a connecting unit300.

The wireless power receiver1000may wirelessly receive power from a transmission side. According to one embodiment, the wireless power receiver1000may wirelessly receive the power using electromagnetic induction. According to one embodiment, the wireless power receiver1000may wirelessly receive the power using resonance.

The electromagnetic induction and resonance may be used when transmitting the power using the magnetic field.

The magnetic substrate100may change the direction of the magnetic field received from the transmission side.

The magnetic substrate100can reduce the amount of the magnetic field to be leaked to the outside by changing the direction of the magnetic field received from the transmission side.

In detail, the magnetic substrate100changes the direction of the magnetic field transferred from the transmission side in the lateral direction such that the magnetic field can be more concentrated onto the coil unit200.

The magnetic substrate100can absorb some of the magnetic field received from the transmission side and leaked to the outside to dissipate the magnetic field as heat. If the amount of the magnetic field leaked to the outside is reduced, the bad influence of the magnetic field exerted on the human body can be reduced.

Referring toFIG. 3, the magnetic substrate100may include a magnet110and a support120.

The magnet110may include a particle or a ceramic.

The support120may include thermosetting resin or thermoplastic resin.

The magnetic substrate100may be prepared in the form of a sheet and may have a flexible property.

Referring again toFIG. 1, the coil unit200may include a first connection terminal210, a second connection terminal220and a coil230. The coil230may be formed as a conductive layer or a conductive pattern.

The first connection terminal210is located at one end of the coil230and the second connection terminal220is provided at the other end of the coil230.

The first and second connection terminals210and220are necessary for connection with the connecting unit300.

The coil230may be formed as a conductive pattern which is obtained by winding a conductive line several times. According to one embodiment, when viewed from the top, the coil pattern may have a spiral shape. However, the embodiment is not limited thereto, and various patterns may be formed.

The coil unit200can be directly disposed on the top surface of the magnetic substrate100. According to one embodiment, an adhesive layer (not shown) may be disposed between the coil unit200and the magnetic substrate100.

The coil unit200may include a conductor. The conductor may include a metal or an alloy. According to one embodiment, the metal may include silver or copper, but the embodiment is not limited thereto.

The coil unit200may transfer the power, which is wirelessly received from the transmission side, to the connecting unit300. The coil unit200can receive the power from the transmission side using the electromagnetic induction or resonance.

The connecting unit300may include a first connection terminal310, a second connection terminal320and a printed circuit board330.

The first connection terminal310of the connecting unit300may be connected to the first connection terminal210of the coil unit200and the second connection terminal320of the connecting unit300may be connected to the second connection terminal220of the coil unit200.

The printed circuit board330may include a wiring layer and a receiver circuit, which will be described later, may be disposed on the wiring layer.

The connecting unit300connects the wireless power receiving circuit (not shown) with the coil unit200to transfer the power received from the coil unit200to a load (not shown) through the wireless power receiving circuit. The wireless power receiving circuit may include a rectifier circuit for converting AC power into DC power and a smoothing circuit for transferring the DC power to the load after removing ripple components from the DC power.

FIGS. 2 and 3are views for explaining the structure of the wireless power receiver1000according to the first embodiment in detail when the coil unit200is connected with the connecting unit300.

FIG. 2is a plan view illustrating the wireless power receiver1000according to the first embodiment.

FIG. 2shows the coil unit200connected with the connecting unit300.

According to one embodiment, the connection between the coil unit200and the connecting unit300may be achieved by a solder. In detail, the first connection terminal210of the coil unit200may be connected to the first connection terminal310of the connecting unit300through a first solder10and the second connection terminal220of the coil unit200may be connected to the second connection terminal320of the connecting unit300through a second solder20. In more detail, the first connection terminal210of the coil unit200may be connected to the first connection terminal310of the connecting unit300through a via hole of the first solder10and the second connection terminal220of the coil unit200may be connected to the second connection terminal320of the connecting unit300through a via hole of the second solder20.

The wireless power receiver1000shown inFIG. 2may be equipped in an electronic appliance, such as a terminal.

The terminal may include a typical mobile phone, such as a cellular phone, a PCS (personal communication service) phone, a GSM phone, a CDMA-2000 phone, or a WCDMA phone, a PMP (portable multimedia player), a PDA (personal digital assistant), a smart phone, or an MBS (mobile broadcast system) phone, but the embodiment is not limited thereto. Various devices can be used as the terminal if they can wirelessly receive the power.

A section taken along line A-A′ of the connecting unit300shown inFIG. 2will be explained with reference toFIG. 3.

FIG. 3is a sectional view taken along line A-A′ of the connecting unit300of the wireless power receiver1000shown inFIG. 2.

Referring toFIG. 3, the first connection terminal210, the second connection terminal220and the coil230constituting the coil unit200are disposed on the top surface of the magnetic substrate100.

In the wireless power receiver1000according to the first embodiment, the coil unit200is directly disposed on the top surface of the magnetic substrate100, so the overall thickness can be remarkably reduced when comparing with the case in which the coil pattern is formed on an FPCB.

Preferably, the magnetic substrate100has a thickness of 0.43 mm and the coil unit200has a thickness of 0.1 mm, so the overall thickness is 0.53 mm. However, this numerical value is illustrative purpose only.

That is, the thickness of the wireless power receiver1000can be reduced by preparing the coil unit200in the form of a conductor, a conductive pattern or a thin film. Since the current trend has tended toward the slimness, if the wireless power receiver1000is applied to the electronic device, such as the portable terminal, the overall thickness of the portable terminal can be reduced and the power can be effectively received from the transmission side.

The connecting unit300is directly disposed on the coil unit200. Since the connecting unit300is directly disposed on the coil unit200, the coil unit200can be readily connected with the connecting unit300.

The first connection terminal210of the coil unit200is connected to the first connection terminal310of the connecting unit300through the solder10.

The second connection terminal220of the coil unit200is connected to the second connection terminal320of the connecting unit300through the solder20.

The coil230may be designed to have a predetermined width W and a predetermined thickness T. In addition, the coil230can be designed to have a predetermined winding interval.

FIGS. 4 to 8are views for explaining a method of manufacturing the wireless power receiver1000according to one embodiment.

The structure of the wireless power receiver1000may be essentially identical to the structure of the wireless power receiver1000described with reference toFIGS. 1 to 3.

Then, referring toFIG. 5, a conductor201is directly laminated on the top surface of the magnetic substrate100. According to one embodiment, the conductor201may be laminated after the adhesive layer has been laminated on the top surface of the magnetic substrate100.

According to one embodiment, a laminating process can be used to form the conductor201on the top surface of the magnetic substrate100. According to the laminating process, the conductor201is heated at the predetermined temperature and then predetermined pressure is applied to the conductor201. The laminating process refers to a process of forming heterogeneous materials, such as a metal foil and a paper, by using heat and pressure.

Then, referring toFIG. 6, a mask500is laminated on the top surface of the conductor201. The mask500may be selectively formed on the top surface of the conductor201corresponding to positions of the first connection terminal210, the second connection terminal220and the coil230of the coil unit200.

After that, referring toFIG. 7, the structure shown inFIG. 6is immersed in an etchant so that portions of the conductor201where the mask500is not positioned may be etched. Thus, the conductor201may have a predetermined conductive pattern.

Then, the coil unit200of the wireless power receiver1000is formed by removing the mask500.

Thereafter, referring toFIG. 8, the soldering work is performed to connect the coil unit200with the connecting unit300.

That is, the first connection terminal210of the coil unit200may be connected to the first connection terminal310of the connecting unit300through the first solder10and the second connection terminal220of the coil unit200may be connected to the second connection terminal320of the connecting unit300through the second solder20.

As described above, since the coil unit200is directly disposed on the top surface of the magnetic substrate100, the overall thickness of the wireless power receiver1000can be remarkably reduced. In addition, since the wireless power receiver1000can be manufactured only through the laminating and etching processes, the manufacturing process may be simplified.FIG. 9is a sectional view taken along line A-A′ of the connecting unit300of the wireless power receiver1000shown inFIG. 2according to the second embodiment.

Referring toFIG. 9, the wireless power receiver1000may include a magnetic substrate100, a coil unit200, a connecting unit300and an adhesive layer700.

The magnetic substrate100, the coil unit200, and the connecting unit300are identical to those described with reference toFIG. 1.

The adhesive layer700is interposed between the magnetic substrate100and the coil unit200to bond the magnetic substrate100to the coil unit200.

FIG. 10is a plan view illustrating a wireless power receiver1000according to the third embodiment.

Referring toFIG. 10, the wireless power receiver1000may include a magnetic substrate100, a coil unit200, a connecting unit300and a short-range communication antenna600.

The magnetic substrate100, the coil unit200and the connecting unit300are identical to those described with reference toFIGS. 1 to 3.

The short-range communication antenna600includes a first connection terminal610, a second connection terminal620and an outer peripheral coil630.

The first connection terminal610and the second connection terminal620of the short-range communication antenna600are connected to the connecting unit300.

The short-range communication antenna600can make near field communication with a reader. The short-range communication antenna600may serve as an antenna that transceives information in cooperation with the reader.

According to one embodiment, the short-range communication antenna600may be arranged at an outer peripheral portion of the coil unit200. According to one embodiment, when the coil unit200is disposed at the center of the magnetic substrate100, the short-range communication antenna600may be arranged along the outer peripheral portion of the magnetic substrate100to surround the coil unit200. The short-range communication antenna600may have a rectangular configuration by winding one conductive line several times, but the embodiment is not limited thereto.

Similar to the coil unit200, the short-range communication antenna600may be formed as a conductive pattern or a conductive layer.

Various short-range communication technologies can be applied to the short-range communication antenna600, and the NFC technology is preferable. The NFC technology has the band of 12.56 MHz and is used for wireless communication in a short distance.

The short-range communication antenna600can be directly disposed on the top surface of the magnetic substrate100.

The method of forming the short-range communication antenna600on the magnetic substrate100may be identical to the method described with reference toFIG. 4.

Hereinafter, a wireless power receiver1000according to the fourth embodiment will be described with reference toFIGS. 11 to 13.

FIG. 11is a perspective view illustrating the wireless power receiver1000according to the fourth embodiment.

Referring toFIG. 11, the wireless power receiver1000includes a magnetic substrate100, a coil unit200and a connecting unit300.

The magnetic substrate100and the coil unit200are identical to those described with reference toFIG. 1. However, the magnetic substrate100is slightly different from the magnetic substrate100described with reference toFIG. 1, so the following description will be made while focusing the difference of the magnetic substrate100.

Referring toFIG. 11, the magnet substrate100is formed with a receiving space130having a structure the same as that of the connecting unit300. That is, referring toFIG. 1, the coil unit200is disposed on the top surface of the magnetic substrate100and the connecting unit300is disposed on the coil unit200. However, referring toFIG. 11, the receiving space130having the structure the same as that of the connecting unit300is formed in the magnetic substrate100, so that the connecting unit300may be disposed under the coil unit200.

FIG. 12is a plan view illustrating a wireless power receiver1000according to the fourth embodiment.

FIG. 12shows the state in which the coil unit200and the connecting unit300are interconnected with each other.

The connecting unit300has a thickness equal to or smaller than a thickness of the magnetic substrate100. The connecting unit300may be implemented as a flexible printed circuit board (FPCB).

The connecting unit300may be disposed in the receiving space130of the magnetic substrate100.

If the thickness of the connecting unit300is equal to or smaller than the thickness of the magnetic substrate100, different from the embodiment shown inFIG. 3, the overall thickness of the wireless power receiver1000can be reduced as much as the thickness of the connecting unit300. In addition, since the usage of the magnet110and the support120can be reduced due to the receiving space130, it is advantageous in terms of cost effectiveness.

FIG. 13is a sectional view taken along line B-B′ of the connecting unit300of the wireless power receiver1000shown inFIG. 12according to the fourth embodiment.

The following description will be made on the assumption that the connecting unit300has a thickness smaller than that of the magnetic substrate100.

Referring toFIG. 13, the first connection terminal210, the second connection terminal220and the coil230constituting the coil unit200are disposed on the top surface of the connecting unit300.

The connecting unit300is disposed under the coil unit200.

The first connection terminal210of the coil unit200is connected to the first connection terminal310of the connecting unit300by the solder10.

The second connection terminal220of the coil unit200is connected to the second connection terminal320of the connecting unit300by the solder20.

The coil230may be designed to have a predetermined width W and a predetermined thickness T. In addition, the coil230can be designed to have a predetermined winding interval.

Referring toFIG. 12, different from the embodiment shown inFIG. 3, the thickness of the connecting unit300is smaller than the thickness of the magnetic substrate100, so the overall thickness of the wireless power receiver1000can be reduced as much as the thickness of the connecting unit300. In addition, since the usage of the magnet110and the support120can be reduced due to the receiving space130, it is advantageous in terms of cost effectiveness.

Hereinafter, a wireless power receiver1000according to the fifth embodiment will be described in detail with reference toFIGS. 14 to 20.

FIG. 14is a perspective view illustrating the wireless power receiver1000according to the fifth embodiment,FIG. 15is a plan view illustrating the wireless power receiver1000according to the fourth embodiment,FIG. 16is a sectional view taken along line C-C′ of the wireless power receiver1000according to the fifth embodiment, andFIGS. 17 to 21are views for explaining a method of manufacturing the wireless power receiver1000according to the fifth embodiment.

First, referring toFIG. 14, the wireless power receiver1000according to the fifth embodiment may include a magnetic substrate100, a coil unit200and a connecting unit300.

According to one embodiment, the wireless power receiver1000can wirelessly receive power from the transmission side using electromagnetic induction. In this case, the coil230of the coil unit200can wirelessly receive power through the electromagnetic induction with a coil of the transmission side.

According to one embodiment, the wireless power receiver1000can wirelessly receive power from the transmission side using resonance.

The magnetic substrate100may change the direction of the magnetic field received from the transmission side.

The magnetic substrate100can reduce the amount of the magnetic field leaked to the outside by changing the direction of the magnetic field received from the transmission side.

The magnetic substrate100can change the direction of the magnetic field received from the transmission side in the lateral direction such that the magnetic field can be more concentrated onto the coil unit200.

The magnetic substrate100can absorb some of the magnetic field received from the transmission side and leaked to the outside to dissipate the magnetic field as heat. If the amount of the magnetic field leaked to the outside is reduced, the bad influence of the magnetic field exerted on the human body can be reduced.

Referring toFIG. 16, the magnetic substrate100may include a magnet110and a support120.

The magnet110may include a particle or a ceramic. According to one embodiment, the magnet110may be one of a spinel type magnet, a hexa type magnet, a sendust type magnet and a permalloy type magnet.

The support120may include thermosetting resin or thermoplastic resin and support the magnetic substrate100.

The magnetic substrate100may be prepared in the form of a sheet and may have a flexible property.

Referring again toFIG. 14, the coil unit200may include a first connection terminal210, a second connection terminal220and a coil230. The coil230may formed as a conductive layer or a conductive pattern.

The coil unit200may be disposed inside the magnetic substrate100. In detail, the coil unit200may be buried inside the magnetic substrate100. In more detail, the magnetic substrate100may include a pattern groove and the coil unit200may be disposed in the pattern groove. The pattern groove may be formed as a conductive pattern or a conductive layer similar to the coil unit200.

The coil unit200has a thickness smaller than that of the magnetic substrate100and an upper portion of the coil unit200may be exposed out of the magnetic substrate100.

A process for manufacturing the wireless power receiver1000by disposing the coil unit200and the connecting unit300in the magnetic substrate100will be described later with reference toFIGS. 17 to 21.

The first connection terminal210of the coil unit200is located at one end of the coil230and the second connection terminal220of the coil unit200is located at the other end of the coil230.

The first and second connection terminals210and220of the coil unit200are necessary for connection with the connecting unit300.

The coil230may be formed as a coil pattern which is obtained by winding a conductive line several times. According to one embodiment, when viewed from the top, the coil pattern may have a spiral shape. However, the embodiment is not limited thereto, and various patterns may be formed.

The coil unit200may transfer the power wirelessly received from the transmission side to the connecting unit300. The coil unit200may transfer the power wirelessly received from the transmission side using the electromagnetic induction or resonance to the connecting unit300.

The connecting unit300may include a first connection terminal310, a second connection terminal320and a printed circuit board330.

The first connection terminal310of the connecting unit300may be connected to the first connection terminal210of the coil unit200and the second connection terminal320of the connecting unit300may be connected to the second connection terminal220of the coil unit200.

The printed circuit board330may include a wiring layer and the wiring layer may include a wireless power receiving circuit, which will be described later.

The connecting unit300connects the wireless power receiving circuit (not shown) with the coil unit200to transfer the power received from the coil unit200to a load (not shown) through the wireless power receiver circuit. The wireless power receiver circuit may include a rectifier circuit (not shown) for converting AC power into DC power and a smoothing circuit for transferring the DC power to the load after removing ripple components from the DC power.

FIGS. 15 and 16show the detailed structure of the wireless power receiver1000according to the fifth embodiment when the coil unit200is connected to the connecting unit300.

FIG. 15shows the coil unit200and the connecting unit300interconnected with each other.

The coil unit200can be connected to the connecting unit300by a solder.

Referring toFIG. 16, the first connection terminal210of the coil unit200may be connected to the first connection terminal310of the connecting unit300through a first solder10and the second connection terminal220of the coil unit200may be connected to the second connection terminal320of the connecting unit300through a second solder20. In detail, the first connection terminal210of the coil unit200may be connected to the first connection terminal310of the connecting unit300through a via hole of the first solder10and the second connection terminal220of the coil unit200may be connected to the second connection terminal320of the connecting unit300through a via hole of the second solder20.

According to one embodiment, the via hole can be formed by using a laser. The laser may include a UV laser or a CO2 laser.

FIG. 16is a sectional view of the wireless power receiver1000in which the magnetic substrate100and the coil unit200are connected to the connecting unit300.

That is, the first connection terminal210, the second connection terminal220and the coil230constituting the coil unit200may be disposed in a pattern groove140of the magnetic substrate100.

In addition, the magnetic substrate100and the coil unit200are connected to the connecting unit300.

The coil230may be designed to have a predetermined width W and a predetermined thickness T and the magnetic substrate100may be designed to have a predetermined thickness T1. According to one embodiment, the coil230has a thickness of 0.1 mm and the magnetic substrate100has a thickness of 0.43 mm, but these numerical values are illustrative purposes only. According to one embodiment, the thickness T of the coil230may be smaller than the thickness T1of the magnetic substrate100.

In the wireless power receiver1000according to the fifth embodiment, the coil unit200is directly disposed in the pattern groove140of the magnetic substrate100, so the overall thickness of an electronic appliance equipped with the wireless power receiver1000can be reduced as much as the thickness of the coil unit200. Thus, if the wireless power receiver1000according to the fifth embodiment is applied to the electronic device, such as the portable terminal, the overall thickness of the portable terminal can be reduced suitably for the current trend of slimness

In addition, in the wireless power receiver1000according to the fifth embodiment, the coil unit200is disposed in the pattern groove140of the magnetic substrate100. Thus, different from the electronic appliance in which a coil pattern is formed on an FPCB, the overall size of the electronic device equipped with the wireless power receiver1000can be reduced.

FIGS. 17 to 21are views for explaining a method of manufacturing the wireless power receiver1000according to the fifth embodiment.

Hereinafter, the method of manufacturing the wireless power receiver1000according to the fifth embodiment will be described with reference toFIGS. 17 to 21as well asFIGS. 14 to 16.

First, referring toFIG. 17, the magnetic substrate100is prepared. According to one embodiment, the magnetic substrate100may be produced by coating metal powder of sendust alloys, such as Al, Fe and SiO2, on polyethylene rubber and then forming an oxide layer on a surface of the polyethylene rubber.

Then, referring toFIG. 18, heat and pressure are applied using a mold1to form the pattern groove in the magnetic substrate100for receiving the coil unit200. The mold1may have the shape corresponding to the shape of the coil unit200. According to one embodiment, the mold1can be manufactured by using an aluminum alloy, a copper alloy or a cast iron.

The mold1may be provided with a protrusion at a region corresponding to the coil unit200for wirelessly receiving the power.

When the heat is applied by using the mold1, the heat having the specific temperature is applied by taking the property of the metal powder of the sendust alloy constituting the magnetic substrate100into consideration. According to one embodiment, if the magnetic substrate100is produced by coating the metal powder of sendust alloy on the polyethylene rubber, when the heat and pressure are applied by using the mold1, high-pressure is applied at the temperature in the range of 100° C. to 180° C., and then the mold100is cooled to the temperature of 100° C. or below. After that, the mold1is separated from the magnetic substrate100. If the mold1is separated just after the pressure has been applied to the magnetic substrate100, the desired pattern groove140may not be formed due to residual heat in the pattern groove140. For this reason, the mold1is separated from the magnetic substrate100after cooling the mold100to the temperature of 100° C. or below.

If the magnetic substrate100is prepared by using the metal powder of sendust alloy, the heat temperature and pressure may vary depending on the distribution and concentration of the metal powder. That is, if the distribution of the metal powder is not uniform, the higher temperature and pressure may be applied. In contrast, if the distribution of the metal powder is uniform, the lower temperature and pressure may be applied. In addition, if the concentration of the metal powder is low, the lower temperature and pressure may be applied as compared with the case in which the concentration of the metal powder is high. Further, the heat temperature and pressure may vary depending on the composition of the metal powder, that is, depending on the alloy constituting the metal powder.

In this manner, the temperature applied to the mold1may vary depending on the distribution, concentration and composition of the powder.

According to one embodiment, laser may be irradiated, instead of applying heat and pressure using the mold1, to form the pattern groove in the magnetic substrate100to receive the coil unit200. In this case, the pattern groove can be formed by using an excimer laser that irradiates the laser beam having a wavelength band of ultraviolet ray. The excimer laser may include a KrF excimer laser (central wavelength 248 nm) or an ArF excimer laser (central wavelength 193 nm).

Next, referring toFIG. 19, the mold1is separated from the magnetic substrate100so that the magnetic substrate100is formed with the pattern groove140.

Then, referring toFIG. 20, the coil unit200is inserted into the pattern groove140formed in the magnetic substrate100. As the coil unit200is inserted into the pattern groove140, a predetermined conductive pattern is formed in the pattern groove140of the magnetic substrate100.

According to one embodiment, a process for forming the coil unit200in the pattern groove140of the magnetic substrate100may include a plating process or a process for inserting a metal which has been etched to have the conductive pattern formed by the coil unit200.

In detail, according to the plating process, the metallic material is filled in the pattern groove140to form the coil unit200. At this time, the metallic material may include one selected from Cu, Ag, Sn, Au, Ni and Pd and the filling of the metallic metal can be performed through one of electroless plating, screen printing, sputtering, evaporation, ink jetting and dispensing or a combination thereof.

Then, referring toFIG. 21, the soldering process is performed to connect the coil unit200with the connecting unit300.

That is, the first connection terminal210of the coil unit200is connected to the first connection terminal310of the connecting unit300through the solder10and the second connection terminal220of the coil unit200is connected to the second connection terminal320of the connecting unit300through the solder20.

As described above, according to the method of manufacturing the wireless power receiver1000of the fifth embodiment, the pattern groove is formed in the magnetic substrate100and the coil unit200is disposed in the pattern groove, so that the overall thickness of the wireless power receiver1000can be reduced. In addition, the wireless power receiver1000can be manufactured by simply forming the pattern groove and then inserting the coil unit into the pattern groove, so that the manufacturing process can be simplified.

FIG. 22is a view for explaining variation of inductance, resistance and Q values of the coil unit200as a function of a usable frequency when the coil unit200is disposed on a top surface of the magnetic substrate according to the first embodiment, andFIG. 23is a view for explaining variation of inductance, resistance and Q values of the coil unit200as a function of a usable frequency when the coil unit200is disposed in the pattern groove formed in the magnetic substrate according to the fifth embodiment.

The inductance, resistance and Q values of the coil unit200can be expressed as following equation 1.
Q=W*L/R[Equation 1]

In equation 1, w is a frequency used when transmitting power, L is inductance of the coil unit200and R is resistance of the coil unit200.

As can be understood from equation 1, the Q value becomes high as the inductance of the coil unit200is increased. If the Q value is increased, the power transmission efficiency can be improved. The resistance of the coil unit200is a numerical value of power loss occurring in the coil unit200and the Q value becomes high as the resistance value is decreased.

Referring toFIGS. 22 and 23, when comparing the fifth embodiment, in which the coil unit200is disposed in the pattern groove140of the magnetic substrate100, with the first embodiment, in which the coil unit200is disposed on the top surface of the magnetic substrate100, when the usable frequency is 150 kHz, the inductance of the coil unit200is increased by 352.42 um from about 9986.92 um to about 10339.34 um and the resistance of the coil unit200is reduced by 0.057Ω from 0.910Ω to 0.853Ω. That is, the Q value is increased corresponding to the increment of the inductance and the reduction of the resistance.

Therefore, the wireless power receiver1000according to the fifth embodiment can increase the Q value by disposing the coil unit200in the pattern groove of the magnetic substrate100.

FIG. 24is an H-field for illustrating a radiation pattern of a magnetic field when the coil unit is disposed on a top surface of the magnetic substrate according to the first embodiment, andFIG. 25is an H-field for illustrating a radiation pattern of a magnetic field when the coil unit is disposed in the pattern groove formed in the magnetic substrate according to the fifth embodiment.

Referring toFIGS. 24 and 25, a greater amount of magnetic fields is radiated from the outer peripheral portion of the coil unit200when the coil unit200is disposed in the pattern groove formed in the magnetic substrate100as compared with the case in which the coil unit200is disposed on the top surface of the magnetic substrate100. This is because the magnetic field directed to the outside is changed in the lateral direction of the coil unit200due to the coil unit200buried in the magnetic substrate100.

In addition, a greater amount of magnetic fields is radiated at the inner portion of the coil unit200when the coil unit200is disposed in the pattern groove formed in the magnetic substrate100as compared with the case in which the coil unit200is disposed on the top surface of the magnetic substrate100. This is also because the magnetic field directed to the outside is changed in the lateral direction of the coil unit200due to the coil unit200buried in the magnetic substrate100.

Referring toFIGS. 24 and 25, the wireless power receiver1000may further include a short-range communication antenna600.

The short-range communication antenna600can make near field communication with a reader. The short-range communication antenna600may serve as an antenna that transceives information in cooperation with the reader.

According to one embodiment, the short-range communication antenna600may be arranged at an outer peripheral portion of the coil unit200. According to one embodiment, when the coil unit200is disposed at the center of the magnetic substrate100, the short-range communication antenna600may be arranged along the outer peripheral portion of the magnetic substrate100to surround the coil unit200. The short-range communication antenna600may have a rectangular configuration by winding one conductive line several times, but the embodiment is not limited thereto.

Similar to the coil unit200, the short-range communication antenna600may be formed as a conductive pattern or a conductive layer.

Various short-range communication technologies can be applied to the short-range communication antenna600and the NFC technology is preferable.

Hereinafter, a wireless power receiver according to another embodiment will be described with reference toFIGS. 26 to 36.

FIG. 26is an exploded perspective view of the wireless power receiver1000according to still another embodiment,FIG. 27is a perspective view of the wireless power receiver1000according to still another embodiment, andFIG. 28is a sectional view of the wireless power receiver1000according to still another embodiment.

Meanwhile,FIG. 27is a perspective view showing the assembled state of the elements of the wireless power receiver1000shown inFIG. 26, in which some elements are omitted.

The wireless power receiver1000according to still another embodiment may be disposed in an electronic device, such as a portable terminal.

Referring toFIGS. 26 to 28, the wireless power receiver1000may include a magnetic substrate100, a coil unit200, a connecting unit300, a short-range communication antenna600, an adhesive layer700, a first dual-side adhesive layer710, a second dual-side adhesive layer720, a protective film800and a release paper layer730.

Referring toFIG. 26, the magnetic substrate100can change the direction of the magnetic field transferred from the transmission side.

The magnetic substrate100changes the direction of the magnetic field transferred to the coil unit200from the transmission side to reduce the amount of the magnetic field leaked to the outside. Thus, the magnetic substrate100may have the electromagnetic wave shielding effect.

In detail, the magnetic substrate100changes the direction of the magnetic field transferred from the transmission side in the lateral direction such that the magnetic field can be more concentrated onto the coil unit200.

The magnetic substrate100can absorb some of the magnetic field transferred to the coil unit200from the transmission side and leaked to the outside to dissipate the magnetic field as heat. If the amount of the magnetic field leaked to the outside is reduced, the bad influence of the magnetic field exerted on the human body can be reduced.

Referring toFIG. 28, the magnetic substrate100may include a magnet110and a support120.

According to one embodiment, the magnet110may be one of a spinel type magnet, a hexa type magnet, a sendust type magnet and a permalloy type magnet.

The support120may include thermosetting resin or thermoplastic resin and support the magnetic substrate100.

Referring again toFIG. 26, the magnetic substrate100may be prepared in the form of a sheet and may have a flexible property.

A receiving space130is formed at a predetermined area of the magnet substrate100. The receiving space130has a structure the same as that of the connecting unit300. The connecting unit300is disposed in the receiving space130and connected to the coil unit200.

The coil unit200can receive the power from the transmission side using the electromagnetic induction or resonance. Similar to the coil unit200illustrated inFIG. 1, the coil unit200may include a first connection terminal210, a second connection terminal220and a coil230. The coil230may be formed as a conductive layer or a conductive pattern.

The connecting unit300connects a receiver circuit (not shown) with the coil unit200to transfer the power received from the coil unit200to a load (not shown) through the receiver circuit.

The connecting unit300may include a wiring layer and the wiring layer may include the wireless power receiving circuit. The wireless power receiving circuit may include a rectifier circuit for rectifying the power received from the coil unit200, a smoothing circuit for removing noise signals, and a main IC chip for performing the operation to wirelessly receive the power.

In addition, the receiver circuit can transfer the signal received from the short-range communication antenna600to a short-range communication signal processing unit (not shown).

The connecting unit300is disposed in the receiving space130of the magnetic substrate100and connected to the coil unit200.FIG. 27shows the connecting unit300disposed in the receiving space130of the magnetic substrate100.

The connecting unit300may include a first connection terminal310, a second connection terminal320, a third connection terminal340and a fourth connection terminal350. The first connection terminal310of the connecting unit300is connected to the first connection terminal210of the coil unit200, the second connection terminal320of the connecting unit300is connected to the second connection terminal220of the coil unit200, the third connection terminal340of the connecting unit300is connected to a first connection terminal610of the short-range communication antenna600and the fourth connection terminal350of the connecting unit300is connected to a second connection terminal620of the short-range communication antenna600.

The connecting unit300may have the shape corresponding to the shape of the receiving space130and may be disposed in the receiving space130. Since the connecting unit300is disposed in the receiving space130of the magnetic substrate100, the thickness of the wireless power receiver1000can be remarkably reduced as much as the thickness of the connecting unit300. Thus, the thickness of the electronic device, such as a portable terminal, equipped with the wireless power receiver1000can be remarkably reduced.

According to one embodiment, the connecting unit300may include a flexible printed circuit board (FPCB), a tape substrate (TS) or a lead frame (LF). If the tape substrate is used as the connecting unit300, the thickness of the connecting unit300can be reduced, so that the overall size of the wireless power receiver1000can be reduced.

If the lead frame is used as the connecting unit300, the wiring layer included in the connecting unit300can be protected from the heat, external moisture or impact and the mass production can be realized.

Referring again toFIG. 26, the short-range communication antenna600can make near field communication with a reader. The short-range communication antenna600may serve as an antenna that transceives information in cooperation with the reader.

According to one embodiment, the NFC signal processing unit (not shown) can process the signal transferred to the short-range communication antenna600through the connecting unit300.

Various short-range communication technologies can be applied to the short-range communication antenna600and the NFC technology is preferable.

According to one embodiment, the short-range communication antenna600may be arranged at an outer peripheral portion of the coil unit200. Referring toFIG. 27, when the coil unit200is disposed at the magnetic substrate100, the short-range communication antenna600may be arranged along the outer peripheral portion of the magnetic substrate100to surround the coil unit200. The short-range communication antenna600may have a rectangular configuration by winding one conductive line several times, but the embodiment is not limited thereto.

Referring again toFIG. 26, the adhesive layer (not shown) may be disposed under the protective film800to form the protective film800on the coil unit200and the short-range communication antenna600, which will be described later in detail.

The first dual-side adhesive layer710is interposed between the magnetic substrate100and the coil unit200/short-range communication antenna600to adhere the coil unit200to the magnetic substrate100, which will be described later in detail. Similar to the magnetic substrate100, a receiving space having the shape identical to the shape of the connecting unit300may be formed in the first dual-side adhesive layer710.

Referring again toFIG. 28, the second dual-side adhesive layer720adheres the protective film800to the release paper layer730, which will be described later in detail.

The coil unit200may be disposed on the magnetic substrate100and may have a spiral structure, but the embodiment is not limited thereto.

Hereinafter, the method of manufacturing the wireless power receiver1000according to still another embodiment will be described with reference toFIGS. 29 to 36.

When the manufacturing process starts, as shown inFIG. 29, the conductor201, the adhesive layer700and the protective film800are prepared.

According to one embodiment, the conductor201may be formed by using an alloy including copper. The copper is in the form of roll annealed copper or electrodeposited copper. The conductor201may have various thicknesses depending on the specification of a product. According to one embodiment, the conductor201may have the thickness of 100 μm, but the embodiment is not limited thereto.

The adhesive layer700is used to reinforce the adhesive strength between the conductor201and the protective film800. The adhesive layer700may include thermosetting resin, but the embodiment is not limited thereto. The adhesive layer may have the thickness of 17 μm, but the embodiment is not limited thereto.

The protective film800protects the conductor201when a predetermined conductive pattern is formed in the conductor201. In detail, the protective film800supports the conductor201in the etching process, which will be described later, to protect the conductor201such that the predetermined conductive pattern can be formed in the conductor201.

According to one embodiment, the protective film800may include polyimide film (PI film), but the embodiment is not limited thereto.

Then, as shown inFIG. 30, the conductor201is formed on the protective film800by the adhesive layer700. The laminating process can be used to form the conductor201on the protective film800. The laminating process refers to the process to bond heterogeneous materials with each other by applying predetermined heat and pressure.

Then, as shown inFIG. 31, a photoresist film900is attached onto the top surface of the conductor201. The photoresist film900is used for etching the conductor201to form a predetermined conductive pattern in the conductor201. A UV exposure type film or an LDI exposure type film may be used as the photoresist film900. According to another embodiment, a photoresist coating solution can be coated on the top surface of the conductor201without using the photoresist film900.

After that, as shown inFIG. 32, the photoresist film900is subject to the exposure and development processes to form a mask pattern910.

The mask pattern910may be formed on the top surface of the conductor201corresponding to the position of the conductive pattern.

The exposure process refers to the process for selectively irradiating light onto the photoresist film900corresponding to the conductive pattern. In detail, in the exposure process, the light is irradiated onto regions of the conductor201where the conductive pattern is not formed. The development process refers to the process for removing the regions to which the light is irradiated through the exposure process.

Due to the exposure and development processes, the mask pattern910may be formed in the regions corresponding to the coil unit200and the short-range communication antenna600. The conductor201exposed through the mask pattern910may be etched.

Then, as shown inFIG. 33, a predetermined portion of the conductor201where the mask pattern910is not formed may be removed through the etching process. The etching process refers to the process of removing the predetermined portion of the conductor201where the mask pattern910is not formed by using a chemical reacting with the predetermined portion of the conductor201. According to one embodiment, the conductor201may be patterned through the wet etching or dry etching.

After that, as shown inFIG. 34, the mask pattern910is removed so that the first and second connection terminals210and220of the coil unit200, the first and second connection terminals610and620of the short-range communication antenna600, the coil230having a predetermined conductive pattern and the short-range communication antenna600having a predetermined conductive pattern may be formed.

Then, as shown inFIG. 35, the soldering process is performed to connect the coil unit200and the short-range communication antenna600to the connecting unit300. According to one embodiment, the soldering process includes the reflow process, but the embodiment is not limited thereto. The reflow process refers to the process for bonding the coil unit230and the short-range communication antenna600with the connecting unit300by melting solder cream using high-temperature heat to ensure the stable electrical connection between the connecting unit300and the coil unit230/NFC antenna600.

The first connection terminal310of the connecting unit300may be connected to the first connection terminal210of the coil unit200by a solder30, the second connection terminal320of the connecting unit300may be connected to the second connection terminal220of the coil unit200by the solder30, the third connection terminal340of the connecting unit300may be connected to the first connection terminal610of the short-range communication antenna600by the solder30and the fourth connection terminal350of the connecting unit300may be connected to the second connection terminal620of the short-range communication antenna600.

Then, as shown inFIG. 36, the magnetic substrate100is laminated on a predetermined portion of the conductive pattern where the connecting unit300is not present. In detail, the magnetic substrate100may be laminated on the top surfaces of the coil230and the short-range communication antenna600.

Prior to the above, the receiving space corresponding to the connecting unit300can be formed at the magnetic substrate100. The receiving space of the magnetic substrate100may have the shape identical to the shape of the connecting unit300.

As described above with reference toFIG. 26, since the connecting unit300is disposed in the receiving space130of the magnetic substrate100, the thickness of the wireless power receiver1000can be remarkably reduced as much as the thickness of the connecting unit300. Thus, the thickness of the electronic device, such as a portable terminal, equipped with the wireless power receiver1000can be remarkably reduced.

The coil230/short-range communication antenna600and the magnetic substrate100may be adhered with each other by the first dual-side adhesive layer710. According to one embodiment, the magnetic substrate100may have the thickness in the range of 100 μm to 800 μm, but the embodiment is not limited thereto. According to one embodiment, the first dual-side adhesive layer710may have the thickness in the range of 10 μm to 50 μm, but the embodiment is not limited thereto.

After that, the release paper layer730is attached to one side of the protective film800by interposing the second dual-size adhesive layer720therebetween. The release paper layer730is a paper layer for protecting the second dual-size adhesive layer720and may be removed when the wireless power receiver is disposed in a case of an electronic device, such as a portable terminal.