WO2015059351A1

WO2015059351A1 - Wireless charging arrangement

Info

Publication number: WO2015059351A1
Application number: PCT/FI2014/050784
Authority: WO
Inventors: Timo Tarvainen; Timo Peltoniemi; Juho PAAVOLA
Original assignee: Elcoflex Oy
Priority date: 2013-10-22
Filing date: 2014-10-16
Publication date: 2015-04-30
Also published as: FI20136042A; EP3061106A1; FI126157B; EP3061106A4

Abstract

In a manufacturing method of the induction charger film according to the invention a first patterned insulation layer (15) is advantageously printed on the surface of a clean copper foil (130). In the following manufacturing stages one or more conductive (16), semi-conductive, insulating material layers or layers including graphics, are printed on the patterned insulation layer (15). When the material layers to be manufactured on the first surface of the induction charger film have been printed, the induction charger film is attached to an appropriate surface film (19). After this copper conductors (131-134) of the induction charger are patterned by etching from the second, yet untreated surface of the metal foil. After etching the conductors a ferrite film (14) is laminated underneath the primary coil (13) and the copper conductors (131-134) of the induction charger, with which ferrite film the magnetic flux created by the primary coil (13) is directed above the primary coil.

Description

Wireless Charging Arrangement

The invention relates to a wireless charging arrangement, in which the main part of the electrical components belonging to the charging arrangement are manufactured with printed electronics. The invention also relates to a charging film accom- plished with printed electronics to be utilized in the charging arrangement.

Prior art

The wireless charging (or induction charging) refers to an arrangement, in which electric energy is transferred from the induction charger to the battery of another device by using the changing electromagnetic field created between the devices. In such charging arrangement electric energy is transferred through the obtained inductive coupling to the battery of the device to be charged. The electrical energy transferred through the magnetic field is mainly utilized for charging the battery of a wireless device. Alternatively, the transferred electric energy is used for the functions of the wireless device. The induction loop in the induction charger creates a changing electromagnetic field, when alternating current is fed to the induction loop. In order to amplify the magnetic field, a coil including several induction loops, which coil is called a primary coil, is used in the induction charger. When alternating current is led to the primary coil, a changing magnetic field is formed around the primary coil. When the secondary coil in the chargeable wireless device is put in the magnetic field formed by the primary coil, then a changing electric current is induced to the conductors of the secondary coil. The battery of the wireless device is charged with this induced electric current. The induction charger requires a short distance between the chargeable device and the charger. The charging distance can be in- creased by setting the induction loops to operate at a certain resonant frequency. The order of magnitude of the used resonant frequencies can be 100-200 kHz.

The Wireless Power Consortium (WPC) has published a Qi standard for standardizing devices related to the wireless charging. A wireless device having a Qi logo can be charged with a Qi standardized charging pad. The Qi standard consists of three parts. The mechanical requirements, the electronic performance characteristics of the induction charger and the chargeable wireless device and the communication between the devices have been determined in the first part. The other parts of the Qi standard focus on the performance of the charging arrangement. The Qi standard presents two induction chargers differing from each other and there are even two different methods of implementation for both of them. The induction chargers differ from each other by the number of the coils and by the localization of the receiver of the wireless device. The simpler induction charger has one primary coil and only one wireless device at a time can be charged with it. In a more complex induction charger several primary coils are used, whereby the location of the receiver of the wireless device can be localized and thus it is possible to charge several devices at the same time.

Figure 1 shows a principled coupling arrangement 10 according to the Qi standard to be utilized in connection with the charging of the battery of one wireless device 2. The exemplary charging arrangement 10 of the Figure comprises an induction charger 1 , which is also called a base station, and an electric power receiver 22 to be utilized in connection with the wireless device 2. Electric energy is transferred with the magnetic flux 17 from the primary coil 13 to the secondary coil 23. A standardized Qi induction charger 1 comprises a system unit 11 and at least one electric power transmitter 12. Every electric power transmitter 12 comprises a primary coil 13 and a conversion unit 121 related to it for feeding the electric current to the primary coil 13. The electric power transmitter 12 also comprises a communication and control unit 122 for starting, maintaining and controlling the charging process.

The wireless device 2 comprises a battery 21 and means for connecting one electric power receiver 22 to a wireless device. The electric power receiver 22 comprises a secondary coil 23 and an electric power capture unit 221 for receiving the electric power transmitted by the magnetic flux 17 generated by the induction charger 1 and converting it to the charging current of the battery 21. The electric power receiver 22 also comprises a control unit 222 for starting, maintaining and controlling the charging process.

The primary coil 13 of the induction charger according to the Qi standard can be for example made of a copper conductor, which is made by weaving thin insulated copper threads together as a Litz wire. By using a Litz wire, the power loss caused by the skin effect developing at high frequencies can be decreased in primary and secondary coils.

The way according to the prior art to couple an induction charger according to the Qi standard to the table is to install at least the primary coil to the cavity made to the side of the lower surface of the table plate, the bottom of which cavity extends near the upper surface of the table. The equipment box, which includes the control electronics of the induction charger, is then fixed to the lower surface of the table. If space consuming equipment boxes cannot be installed to the lower surface of the table because of the operating environment of the table, expensive special installations must be made for installing the induction charger.

In a corresponding way, the secondary coil together with its control electronics to be coupled or incorporated to the wireless device according to the prior art is a space consuming solution. Also so-called printed electronics can be used in the manufacture of electric circuit complexes. In this manufacturing method the printing plate or the ink material in the printing plate contacts and adheres to the material functioning as a print carrier. An electrically insulating material, on which the desired electric circuit complexes are manufactured by printing several material layers on top of each other, is generally used as a printing carrier. Fluid or powdery materials are available for manufacturing of both electrically conductive, insulating, semi-conductive or optical circuit elements.

Objects of the invention

The object of the invention is to disclose a flexible, film-like circuit arrangement including printed electronics to be utilized in a wireless charging arrangement, by which circuit arrangement an induction charger according to the invention as well as electrical circuit components to be connected to a wireless device and to be utilized in the electric power transmission can be manufactured cost-effectively. An advantageously planar induction charger according to the invention or the electric power receiving circuits of the wireless device can be manufactured with a reel-to- reel manufacturing equipment, which is suitable for the manufacture of the flexible circuit board. The induction charger according to the invention can be attached on the surface of any table, for example by gluing or self-adhesion.

The objects of the invention are obtained by an induction charger, the spiral-like primary coil of which is manufactured on a flexible circuit board by etching it from a metal foil included in the flexible circuit board. The metal foil is advantageously a copper foil. In addition to the primary coil, also different indicators of the induction charger, such as leds, can be manufactured on the same flexible circuit board by printed electronics. The graphic symbols and patterns of the induction charger ac- cording to the invention can be manufactured on the control electronics by the printing technique.

An advantage of the induction charger according to the invention is that the induction charger is a flexible, film-like circuit complex, which can be directly attached onto the surface to be used.

Further, an advantage of the invention is that the order of magnitude of the total thickness of the induction charger film is 1 mm.

Furthermore, an advantage of the invention is that the table surface, on which the induction charger film according to the invention is attached, need not be sepa- rately processed for attaching the induction charger.

Further, an advantage of the invention is that the induction charger film can also be attached to metal table surfaces.

Furthermore, an advantage of the invention is that the primary coil and the electronic circuits of the induction charger can be manufactured by the reel-to-reel technique by utilizing printed electronics, whereby the turnaround time required by the manufacture of the induction charger is short due to which the manufacturing costs are reduced.

Furthermore, an advantage of the invention is that optical components can be manufactured in connection with the induction charger by printed electronics, which optical components are utilized in the signal light elements or in the data transmission elements of the induction charger.

Yet an advantage of the invention is that also the receiving arrangement receiving the electric power of the wireless device acting as a counterpart of the induction charger can be entirely manufactured with the same manufacturing method than the induction charger according to the invention. In an advantageous embodiment the power receiver according to the invention is manufactured as a part of the cover of the battery charger of the wireless device.

The induction charger film according to the invention, which induction charger film comprises - a surface film and - at least one spiral-like primary coil of an induction charger etched from a copper foil, is characterised in that it additionally comprises

- printed graphic elements of the induction charger between a surface film and the wiring etched from the copper foil of the induction charger

- passive circuit elements and/or semi-conductive circuit elements implemented by printed electronics of the induction charger as well as

- a ferrite film glued on the side of the lower surface of the primary coil.

The receiver film of the wireless device according to the invention, which receiver film comprises

- a secondary coil of a spiral-like induction charger etched from the copper foil and

- a surface film glued on the side of a first surface of the secondary coil, is characterised in that it further comprises

- conductors and/or semi-conductive circuit elements of a power receiver imple- mented by printed electronics

- graphic elements of the power receiver printed on the side of the first surface of the secondary coil as well as

- a ferrite laminate glued on the side of a second surface of the secondary coil.

The manufacturing method of an induction charger film according to the invention, in which method electric circuit elements are printed with a reel-to-reel manufacturing equipment, is characterised in that

- a first patterned insulation layer is added on a first clean surface of a clean copper foil

- at least one patterned layer of conductive material is added on the insulating layer for manufacturing a wiring of an induction charger

- graphic elements are added on the side of a first surface of the copper foil

- a surface film is attached on the graphic layer - after attaching the surface film a primary coil and at least a part of conductors of the induction charger are etched from the metal film as well as

- a ferrite film is laminated underneath the primary coil of the induction charger.

Some advantageous embodiments of the invention are presented in the depend- ent claims.

The basic idea of the invention is the following: the primary coil of an advantageously film-like induction charger according to the invention is manufactured by etching from a metal foil of a flexible circuit board. The metal foil can be for example a copper foil. In an advantageous embodiment of the invention, on a first sur- face, on the upper surface, of an etched primary coil, there is an insulation layer, a bridge, advantageously manufactured by printing, on which a conductor is printed from a conductive material from an inner end of the primary coil to a copper conductor connecting the induction charger to the control electronics. Graphic elements controlling the use of the induction charger are advantageously printed on the insulation and conductive layer. On the graphic elements as an uppermost material layer there is an at least partly transparent surface film advantageously attached by a hot-setting adhesive.

In another advantageous embodiment of the invention, there is a first patterned insulation layer on a second surface, on the lower surface, of a spiral-like primary coil, which insulation layer is manufactured on the etched spiral-like primary coil and on the related circuitry patterns. The insulation layer is advantageously manufactured by pressing, printing or growing. A conductor is manufactured on the insulation layer advantageously by silver printing. With this conductor an inner end of the spiral-like primary coil of the induction charger is connected to a conductor connecting the induction charger according to the invention to the control electronics.

In both embodiments on the patterned first insulation layer there can additionally be one or more conductive, semi-conductive or insulating material layers, by which the electric circuitries and optical indicator components of the induction charger according to the invention are manufactured.

When all the electric circuit elements of the induction charger according to the invention to the upper and/or lower side of the primary coil are finished, a ferrite laminate is attached on the lower surface of the induction charger film according to the invention. A support film of the ferrite laminate is glued on side of the lower surface of the primary coil by a hot-setting adhesive. The magnetic field created by the primary coil is arranged to be formed by ferrite so that the magnetic flux caused by the current passing in the primary coil is mainly directed above the primary coil towards the wireless device acting as a counterpart. Thus, the main part of the magnetic flux caused by the primary coil is directed towards the secondary coil in the wireless device. On the side of the ferrite laminate to be arranged against the table surface there is advantageously glue, with which the induction charger according to the invention can be attached to the table surface.

In the following, the invention will be described in detail. In the description, refer- ence is made to the enclosed drawings, in which

Figure 1 shows the main parts of the induction charger according to the Qi standard,

Figure 2 shows by the way of an example some components of a primary coil of the first embodiment of the induction charger according to the invention seen from above,

Figure 3a shows as an exemplary cross-sectional view some parts of the induction charger film according to the first embodiment of the invention,

Figure 3b shows as an exemplary cross-sectional view some parts of the induction charger film according to the second embodiment of the invention, Figure 4a shows as an exemplary flow chart the main stages of the manufacturing method of the induction charger film according to the first embodiment of the invention and

Figure 4b shows as an exemplary flow chart the main stages of the manufacturing method of the induction charger film according to the second embodi- ment of the invention.

The embodiments in the following description are only exemplary and a person skilled in the art can carry out the basic idea of the invention also in some other way than what is described in the description. Even though it may be referred to an embodiment or embodiments in several places of the description, this does not mean that the reference would be directed to only one described embodiment or that the described characteristic would be usable only in one described embodi- ment. The individual characteristics of two or more embodiments may be combined and new embodiments of the invention may thus be provided.

The induction charger of Figure 1 is presented in connection with the description of the prior art. Figure 2 shows by the way of an example the structure of the spiral-like primary coil 13 of the induction charger according to the first embodiment of the invention seen from above. For the sake of clarity, Figure 2 does not show all material layers to be manufactured or laminated above the primary coil 13 according to the invention. The spiral-like primary coil 13 of the induction charger according to the first embodiment of the invention is advantageously etched from an originally clean metal foil 130. The clean metal foil 130 is advantageously a copper foil, to which no separate plastic film has been laminated as a support element. The copper conductors 131 , 132 and 134 manufactured by etching from the copper foil 130 as well as the connecting point 133 can be seen in Figure 2. In the manufacturing process according to this embodiment of the invention the copper foil functions in the initial phases of the manufacturing process as a support element required by the printing processes, thus no separate plastic support film is needed in the beginning of the manufacturing process in addition to the copper foil. The order of magnitude of the thickness of the copper foil 130 is advantageously 35 μιη. In this embodiment a bridge 15, which extends over the turns 134 of the primary coil 13, is printed in the first working phase from an insulating material on a first surface, on the upper surface, of the clean copper foil 130. In the next phase, a conductor 16 has been printed from a conducting material on the bridge 15 manufactured of insulating material, with which conductor an inner end 133 of the spiral- like primary coil 13 is connected to a first end of the copper conductor 132. The printed conductor 16 can be advantageously manufactured for example by the silver paste printing. The conductor 132 is connected from its second end to electronic circuits of the induction charger according to the invention.

After manufacturing the conductor 16, an insulation layer (not shown in Figure 2) has been printed in an advantageous embodiment of the invention on the first surface of the conductor 16 and the clean copper foil 130. Further, graphic elements have been advantageously printed on the insulation layer (not shown in Figure 2), which graphic elements are utilized in the use of the induction charger (not shown in Figure 2). A surface film (not shown in Figure 2), which is at least partly trans- parent, has been attached on the graphic elements with a hot-setting adhesive. The surface film can advantageously be a fire classified film, such as for example a film complying to class UL 94 V0.

In another advantageous embodiment according to the invention the graphic elements have been directly printed on the first surface of the conductor 16 and the copper foil 130.

In both embodiments, it has been possible to print the graphic elements either with spot colours or as a multi-colour halftone printing.

When the surface film has been hot glued so as to fix to the copper foil, the etching of the turns 134 and the conductors 131 and 132 of the primary coil 13 can be performed from the clean second surface, from the lower surface, of the copper foil 130. After the etching, the turns 134 and the conductors 131 and 132 of the primary coil 13 are finished.

When the primary coil 13 and the conductors 131 and 132 have been etched, a ferrite laminate 14 has been hot glued at least under the primary coil 13, so that a support film of the ferrite laminate is towards the copper parts etched from the copper foil 30. The magnetic field caused by the current passing in the primary coil 13 is formed with the ferrite laminate 14 so that the main part of the magnetic flux 17 developing underneath the primary coil 13 is directed above the primary coil 13. On the lower surface of the ferrite laminate 14 there is advantageously glue, with which the finished induction charger film according to the invention is attached to a table surface. The table surface need not be processed in any way in order to attach the induction charger film according to the invention. The table surface can be made of wood or metal. Figure 3a shows a cross-sectional structure of the induction charger film 100a of Figure 2 near the point of contact of the outer end of the primary coil 13 and the copper conductor 132. The surface film 19, which is advantageously made of fire classified material, is shown uppermost in Figure 3a. The order of magnitude of the thickness of the surface film 19 is advantageously 25 pm. The surface film can be advantageously made of PET (polyethylene terephtalate) film. The surface film 19 is attached by a hot-setting adhesive film 17a (hot melt glue) on a printed layer 8 including the graphic elements. The order of magnitude of the thickness of the hot-setting film 7a is advantageously 75 pm. The order of magnitude of the thickness of the printed layer 18 including the graphic elements is advantageously 30 pm.

The conductor made with silver paste, which conductor connects the connection point 33 (not shown in Figure 3a) to the conductor 132, is shown with reference numeral 16. The order of magnitude of the thickness of the conductor 16 is advantageously 15 μιη.

Under the printed conductor 16 there is a 30 μιτι thick printed insulation layer, the bridge 15.

The cross-sections of the conductors of the four outermost turns of the spiral-like primary coil 13 are shown with reference numeral 134. The reference numeral 132 shows a copper conductor to be arranged to the outer end of the primary coil 13. The order of magnitude of the thickness of the copper conductors 134 and 132 is advantageously 35 μιη.

A hot-setting adhesive film, the order of magnitude of which is 75 μηη, on the sec- ond surface, on the lower surface, of the primary coil 13 is shown with reference numeral 17b. The film including the etched copper conductors is attached to the support film 1 a of the ferrite laminate with a hot-setting adhesive film 17b.

Underneath the hot-setting adhesive film 17b there is a ferrite laminate 14, a support film 14a of which is against the hot-setting adhesive film 17b. The support film 14a is advantageouly a PET film. The order of magnitude of its thickness is 25 pm. The order of magnitude of the thickness of the ferrite film 14 is advantageously 300 pm. On the lower surface of the ferrite film 14 there is advantageously a pressure sensitive adhesive film 17c. The induction charger film according to the invention is arranged to be attached to the table surface with an adhesive film 17c. The order of magnitude of the thickness of the adhesive film 17c is 50 μιη.

Figure 3b shows a cross-sectional structure according to the second embodiment 100b of the induction charger film according to the invention near the point of connection of the outer end of the primary coil 13 and the conductor 132. The surface film 19, which is advantageously made of fire classified material, is shown upper- most in Figure 3b. The order of magnitude of the thickness of the surface film 19 is advantageously 25 pm. The surface film can be made of PET (polyethylene ter- ephtalate) film, for example. The graphic elements of the induction charger film, the layer 18, is printed on the lower surface of the surface film 19. The order of magnitude of the thickness of the printed layer 18 including the graphic elements is advantageously 30 pm.

The surface film 19 and the layer 18 including the graphic elements is attached to the support film 130a of the copper laminate 135 with a hot-setting adhesive film 17d. The order of magnitude of the thickness of the hot-setting adhesive film 17d is advantageously 75 pm.

The support film 130a of the copper laminate 135 is advantageously made of polycarbonate (PC film), the order of magnitude of the thickness of which is 75 pm. The support film 130a of the copper laminate 135 is glued to the copper foil 130 with an adhesive layer 130b, the order of magnitude of the thickness of which is 10 pm.

In this advantageous embodiment the etching of the turns 134 and the copper conductors 131 and 132 of the primary coil 13 is made after joining the surface film structure and the copper laminate 135. The etching has been made from the second surface, from the lower surface, of the copper foil 130. The order of magnitude of the thickness of the conductors 134 and the copper conductor 132 of the primary coil is advantageously 35 pm.

On the etched turns 134 of the primary coil 13 there is a bridge 15 printed from an insulating material.

A conductor 16, which connects the inner end (not shown in Figure 3b) of the primary coil 13 to the copper conductor 132, is printed from a conductive material on the bridge 15. The conductor 16 is advantageously made of silver paste. The order of magnitude of the thickness of the printed conductor 16 is advantageously 15 pm.

The hot-setting adhesive film, the order of magnitude of the thickness of which is 75 pm, on the side of the second surface, on the lower surface, of the primary coil 13 is shown with reference numeral 17e. The film including the etched conductors is attached to the ferrite laminate with a hot-setting adhesive film 17e. Underneath the hot-setting adhesive film 17e there is a ferrite laminate, the support film 14a of which is against the hot-setting adhesive film 17e. The support film 14a is advantageously a PET film. The order of magnitude of its thickness is 25 pm. The order of magnitude of the thickness of the ferrite film 14 is advantageous- ly 300 μιτι. On the lower surface of the ferrite film 14 there is advantageously a pressure sensitive adhesive film 17c. The induction charger film according to the invention is arranged to be attached to the table surface with an adhesive film 17c. The order of magnitude of the thickness of the adhesive film 17c is 50 pm. Figure 4a shows as an exemplary flow chart the main stages of the manufacturing method of the flexible induction charger film 100a according to the first embodiment of the invention. In connection with the description of the flow chart of Figure 4a, the reference numerals shown in more detail in Figure 3a are used as clarifying reference numerals. Phase 400 precedes the actual manufacturing stages of the flexible induction charger film 100a. In stage 400, there is a finished clean metal foil 130, which is advantageously a copper foil.

The order of magnitude of the thickness of the copper foil 130 is advantageously 35 pm. The copper coil 130 is packed to a coil, which can be used in a reel-to-reel printing machine. The copper foil 130 has two surfaces, which are in the following called as the first surface and as the second surface. In an exemplary structure of Figure 3a the first surface can also be called as the upper surface of the copper foil 130 and the second surface as its lower surface.

In phase 410, a first patterned insulation layer, which is utilized at least as a bridge 15, is pressed, printed or grown on the first surface (upper surface in Figure 3a) of the copper foil 130. The order of magnitude of the thickness of the insulation layer can advantageously be 30 pm.

In phase 41 , a conductor 16, which can be for example silver paste or silver ink, is printed on the bridge 15. The order of magnitude of the thickness of the conduc- tor 16 can advantageously be 15 pm.

After the printing of the conductor 16, it is decided in the controlling stage 412, if new insulation layers are printed. If the conclusion is "Yes", it is returned in the manufacturing process to phase 410, in which a new patterned insulation layer is printed on the first surface of the copper foil 130. In an advantageous embodiment of the invention also a new patterned conductor layer can be advantageously printed on this insulation layer. This process loop 410^412 is repeated until the controlling phase 412 generates the conclusion "No", whereby the manufacturing process progresses to phase 413. In phase 413, the graphic elements, such as symbols and/or texts, included in the induction charger film, are printed on side of the first surface of the copper foil 130. For example spot colours or multicolour halftone printing can be utilized in the printing. If the graphic elements are printed on the insulation film or on the first sur- face of the clean copper foil 130, depends on the preceding stages. The order of magnitude of the thickness of the printed graphic layer is advantageously 30 prn.

In phase 414, the surface film 19 is attached with a hot-setting adhesive layer 17a to the copper foil 130 including the printed graphic elements. In the following process stages the surface film 19 functions also as a support film of the copper foil 130.

When the support film 19 is attached on the first surface of the copper foil 30 of the induction film 100a according to the invention, the copper turns 134 as well as the conductors 131 and 132 of the primary coil 13 can be manufactured in phase 420 by etching on the yet solid second surface of the copper foil 130. In phase 421 , a hot-setting adhesive layer 17b is printed on the etched copper conductors.

In phase 422, a ferrite laminate 14, the order of magnitude of the thickness of which is 300 pm, is attached to the hot-setting adhesive layer 17b. The ferrite laminate is attached from the support film 14a to the hot-setting adhesive layer 17b. Phase 423 is optional. In this stage, an adhesive layer 17c can be printed on the outer surface of the ferrite film 14. After printing the adhesive layer 17c the induction charger film 100a according to the invention is finished, Phase 430. With the aid of the adhesive layer 17c the finished induction charger film 100a can be attached for example to the table surface. The material of the table surface can be wood, plastic or metal.

Figure 4b shows as an exemplary flow chart the main stages of the manufacturing method of the flexible induction charger film 00b according to the second embodiment of the invention. In connection with the description of the flow chart of Figure 4b, the reference numerals shown in more detail in Figures 3b are used as clarify- ing reference numerals.

Phase 440 precedes the actual manufacturing stages of the second advantageous embodiment of the flexible induction charger film 100b. In stage 440, the surface film 19 and the copper laminate 135, which advantageously comprises a copper foil 130, on the first surface, on the upper surface, of the copper foil 130 an adhesive layer 30b, as well as a plastic support film 130a attached to the adhesive layer. The support film 130a can be for example made of polycarbonate.

The order of magnitude of the thickness of the copper foil 130 of the copper lami- nate 135 is also in this embodiment advantageously 35 pm. The copper laminate 135 to be used in the manufacture is packed to a coil, which can be used in a reel- to-reel printing machine. The copper laminate 135 and the copper foil 130 have two surfaces, which are in the following called as a first surface and as a second surface. In an exemplary structure of Figure 3b the first surface can also be called as the upper surface and the second surface as the lower surface.

In phase 450, the graphic elements, such as symbols and/or texts included in the induction charger film 100b, are printed on the lower surface of the surface film 19, which in the finished induction charger film 100b is against the finished primary coil. For example spot colours or multicolour halftone printing can be utilized in the printing. The order of magnitude of the thickness of the printed layer 18 including the graphic elements is advantageously 30 pm.

In phase 451 , a hot-setting adhesive layer 17d is printed on the layer 18 including the graphic elements.

In phase 452, the copper laminate 135 is laminated from its support film 130a with the aid of the hot-setting adhesive layer 17d to the surface film 19.

When the surface film 19 is attached on the first surface (upper surface) of the copper laminate 135 of the induction film 100b according to the second embodiment of the invention, copper turns 134 as well as copper conductors 131 and 132 of the primary coil 13 can be manufactured in stage 460 by etching on the solid second surface of the copper foil 130 of the copper laminate 135.

In phase 461 , the first patterned insulation layer is printed or grown at least on the etched turns 134 of the primary coil 13. The printed insulation layer is advantageously utilized as a bridge 15. The order of magnitude of the thickness of the insulation layer can advantageously be 30 pm. In phase 462, a conductor 16, which can be for example silver paste or silver ink, is printed on the bridge 15. The connecting point 133 of the inner end of the primary coil 13 is connected to the copper conductor 132 with the printed conductor 16. The order of magnitude of the thickness of the printed conductor 16 is advantageously 15 pm.

After printing the conductor 16, it is decided in the controlling phase 463, if new insulation layers are printed. If the conclusion is "Yes", it is returned to phase 461 in the manufacturing process, in which stage at least a new patterned insulation layer is printed. In an advantageous embodiment of the invention also a new patterned conductor layer can be advantageously printed on the insulation layer. This process loop 461-463 is repeated until the controlling phase 463 generates the conclusion "No", whereby the manufacturing process progresses to phase 464. In phase 464, a hot-setting adhesive layer 17e is printed on the etched copper conductors (on the lower surface). The order of magnitude of the thickness of the hot-setting adhesive layer 17e is 75 μηι.

In phase 465, a ferrite laminate 14, the order of magnitude of the thickness of which is 300 μιτι, is attached to the hot-setting adhesive layer 17b. The ferrite lam- inate 14 is attached from its support film 14a to the hot-setting adhesive layer 17b.

Phase 466 is optional. In this phase, the adhesive layer 17c can be advantageously printed on the outer surface of the ferrite film 14. After printing the adhesive layer 17c the induction charger film 100b according to the invention is finished, phase 470. The finished induction charger film 100b can be attached to the table surface with the aid of the adhesive layer 17c. The material of the table surface can be wood, plastic or metal.

In the third advantageous embodiment of the invention the induction charger film according to the invention is integrated as a part of the plastic extruded 3D component. In this embodiment, the adhesive layer 17c is not necessarily needed, since the finished induction charger film is directly attached to the injection mould plastic. The 3D component can be for example curved.

The power receiving unit 22 of the wireless device 2 shown in Figure 1 can be advantageously implemented with the structure according to this embodiment.

In the above-described manufacturing method according to the invention the flexi- ble induction charger film can be manufactured by the reel-to-reel technique either to the clean copper foil or copper laminate. The problems appearing in connection with the induction charger according to the prior art can be avoided by the manufacturing method according to the invention. It is obvious for the person skilled in the art that also other optical circuit elements based on coils or semi-conductors can be included in the flexible induction charger film 100a or 100b according to the invention by the printing technique. Thus, also for example different antennas can be manufactured to the induction charger film according to the invention for a short distance data transfer. In such case, energy can be fed through the primary coil - secondary coil arrangement of the Qi charger arrangement to the radio parts of the antenna arrangement in a device including a secondary coil. Thus, data can be transferred from the wireless device through the induction charger film to an outer data transfer network. Small single components can be connected (so to say bonded) to the induction charger film according to the invention, whereby the Qi induction charger according to the standard can be advantageously entirely integrated to the induction charger film according to the invention.

Some advantageous embodiments of the flexible induction charger according to the invention and advantageous embodiments of the manufacturing method of the induction charger film according to the invention have been described above. The invention is not limited to the solutions described above, but the inventive idea can be applied in numerous ways within the scope of the claims.

Claims

Claims:

1. An induction charger film (100a, 100b) comprising

- a surface film (19) and

- at least one spiral-like primary coil (13) of the induction charger (1 ) etched from a copper foil ( 30), characterised in that the induction charger film further comprises

- printed graphic elements (18) of the induction charger between the surface film (19) and wiring (131-134) etched from the copper foil of the induction charger

- passive circuit elements (16) and/or semi-conductive circuit elements imple- mented by printed electronics of the induction charger (1 ) as well as

- a ferrite film (14) glued on a side of a lower surface of the primary coil (13).

2. The induction charger film (100a) according to claim 1 , characterised in that a conductor (16) connecting an inner end (133) of the primary coil (13) of the induction charger to electronics of the induction charger is printed on a patterned insulation layer (15) printed on a side of an upper surface of the primary coil.

3. The induction charger film (100a) according to claim 2, characterised in that electrical and/or optical circuit elements of the induction charger film (100a) are printed on the patterned insulation layer (15) printed on the side of the upper surface of the primary coil. 4. The induction charger film (100a) according to claim 2 or 3, characterised in that the graphic elements (18) of the induction charger are printed on the patterned insulation layer (15) printed above of the primary coil (13).

5. The induction charger film (100a) according to claim 4, characterised in that the spiral-like primary coil (13) of the induction charger etched from the metal foil (130) of the induction charger (1 ) and its conductors (131 , 132) connecting it to the electronics are fixed in their upper surfaces from the lower surface of the surface film (19).

6. The induction charger film (100a) according to claim 2, characterised in that a ferrite laminate (14) is glued to the side of the second surface of the primary coil (13), which ferrite laminate is configured to direct a magnetic flux to be created to the side of the second surface of the primary coil (13) to the side of the upper surface of the primary coil (13) in order to amplify an overhead magnetic flux ( 7).

7. The induction charger film ( 00b) according to claim 1 , characterised in that a conductor (16) connecting an inner end (133) of the primary coil (13) of the in- duction charger (1 ) to electronics of the induction charger is printed on a patterned insulation layer (15) printed on a side of a second surface of the primary coil (13).

8. The induction charger film (100b) according to claim 7, characterised in that electrical and/or optical circuit elements of the induction charger film (100b) are printed on the patterned insulation layer (15) printed on the side of the lower sur- face of the primary coil.

9. The induction charger film (100b) according to claim 7 or 8, characterised in that a ferrite laminate (14) is attached on the circuit elements on the side of the second surface of the primary coil (13), which ferrite laminate is configured to direct a magnetic flux developing to the side of the lower surface of the primary coil (13) to the side of the upper surface of the primary coil in order to amplify an overhead magnetic flux (17).

10. The induction charger film according to claim 6 or 9, characterised in that there is glue (17c) on the outer surface of the ferrite laminate (14), with which glue the induction charger film (100a, 100b) is configured to be attached to a table sur- face.

1 1. The induction charger film (100a, 100b) according to claim 1 , characterised in that the surface film (19) is fire classified.

12. The induction charger film (100b) according to claim 1 or 11 , characterised in that the graphic elements of the induction charger are printed on the lower sur- face of the surface film (19).

13. The induction charger film (100a, 100b) according to claim 10, characterised in that the induction charger film is planar.

14. The induction charger film (100a, 100b) according to claim 6 or 9, characterised in that the induction charger film (100a, 100b) is configured to be located as a curved surface inside a piece to be injection moulded.

15. The induction charger film (100a, 100b) according to claim 6, 9 or 14, characterised in that the induction charger film further comprises electronic data transfer circuits. 6. A receiving film of a wireless device (2) comprising - a secondary coil (23) of a spiral-like induction charger (100a, 00b) etched from a copper foil and

- a surface film glued on a side of a first surface of the secondary coil (23), characterised in that the receiver film further comprises

- conductors and/or semi-conductive circuit elements of a power receiver (22) im- plemented by printed electronics

- a glued ferrite laminate laminated on a side of a second surface of the secondary coil. 17. A manufacturing method (100a) of an induction charger film, in which passive and active circuit elements of the induction charger are printed with a reel-to-reel manufacturing equipment, characterised in that in the manufacturing method

- a first patterned insulation layer (15) is added (410) on a first clean surface of a clean copper foil (130) - at least one patterned layer (16) of conductive material is added (411 ) on the insulating layer (15) for manufacturing a wiring of the induction charger

- graphic elements ( 8) are added (413) on the side of the first surface of the copper foil

- a surface film (19) is attached (414) on the graphic layer (18) - after attaching the surface film (19) a primary coil (13) and at least a part of conductors (131 , 132) of the induction charger ( 00a) are etched (420) from the metal foil (130) as well as - a ferrite film (14) is laminated (422) underneath the primary coil (13) of the induction charger.

18. The manufacturing method according to claim 17, characterised in that the material layers are added by pressing, printing or growing.