(19)
(11)EP 2 476 179 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
05.07.2017 Bulletin 2017/27

(21)Application number: 10760028.0

(22)Date of filing:  01.09.2010
(51)International Patent Classification (IPC): 
H02J 5/00(2016.01)
H01F 7/02(2006.01)
H01F 38/14(2006.01)
(86)International application number:
PCT/IB2010/053923
(87)International publication number:
WO 2011/030256 (17.03.2011 Gazette  2011/11)

(54)

AN ELECTRONIC DEVICE AS WELL AS A BASE PART AND AN ELECTRONIC ELEMENT SUITABLE FOR USE IN SUCH AN ELECTRONIC DEVICE

ELEKTRONISCHE VORRICHTUNG SOWIE EIN BASISTEIL UND EIN ELEKTRONISCHES BAUTEIL FÜR DIE ANWENDUNG IN DERARTIGER ELEKTRONISCHEN VORRICHTUNG

DISPOSITIF ÉLECTRONIQUE ET PARTIE BASE, ET ÉLÉMENT ÉLECTRONIQUE POUVANT SERVIR DANS CE DISPOSITIF


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

(30)Priority: 09.09.2009 EP 09169831

(43)Date of publication of application:
18.07.2012 Bulletin 2012/29

(73)Proprietor: Philips Lighting Holding B.V.
5656 AE Eindhoven (NL)

(72)Inventors:
  • WILLEMSEN, Oscar, Hendrikus
    NL-5656 AE Eindhoven (NL)
  • WAFFENSCHMIDT, Eberhard
    NL-5656 AE Eindhoven (NL)
  • BREMER, Petrus, Johannes
    NL-5656 AE Eindhoven (NL)

(74)Representative: van Eeuwijk, Alexander Henricus Waltherus et al
Philips Lighting B.V. Philips Lighting Intellectual Property High Tech Campus 45
5656 AE Eindhoven
5656 AE Eindhoven (NL)


(56)References cited: : 
EP-A2- 0 823 717
WO-A2-2009/105615
US-A1- 2008 129 246
WO-A2-2006/097870
US-A1- 2007 279 002
  
  • Anonymous: "Magnetic core", Wikipedia, the free encyclopedia , 6 September 2009 (2009-09-06), pages 1-9, XP002633916, Retrieved from the Internet: URL:http://en.wikipedia.org/w/index.php?ti tle=Magnetic_core&oldid=312236601 [retrieved on 2011-04-21]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

FIELD OF THE INVENTION



[0001] The invention relates to an electronic device being provided with at least a base part and an electronic module, which base part comprises a soft magnetic layer and at least a primary coil, whereas the electronic module comprises at least one electronic element and at least a secondary coil adapted to inductively interact with the primary coil.

[0002] The invention also relates to a base part suitable for use in such an electronic device.

BACKGROUND OF THE INVENTION



[0003] In such an electronic device, which is known from WO/2008/012702 A1, the base part comprises a soft magnetic layer to improve the inductive coupling between the primary and secondary coil. The base part is provided with a number of primary coils.

[0004] Positioning elements are provided on both the base part and the electronic module to place the electronic module on the base part in a predefined position so that the inductive coupling between the primary coil and the secondary coil is at the optimum. Furthermore, the positioning elements hold the electronic module at its place on the base part. Other related art electronic devices are known from WO 2006/097870 and EP 0 823 717 A2.

SUMMARY OF THE INVENTION



[0005] It is an object of the invention to provide an electronic device wherein a fixation between the electronic module and the base part is improved.

[0006] This object is accomplished with the electronic device according to independent device claim 1 in that the electronic module further comprises at least one magnet adapted to magnetically interact with the soft magnetic layer, and in that the soft magnetic layer is provided with a number of primary coils located in holes, wherein at least one slit extends between adjacent holes.

[0007] Since the primary coil is located in a hole of the soft magnetic layer, the primary coil and the soft magnetic layer can be located in the same plane due to which both the distance between the primary coil and the secondary coil as well as the distance between the soft magnetic layer and the magnet can be relatively small. Due to the relatively small distance between the primary coil and the secondary coil, a good inductive power transmission will be obtained. Due to the relatively small distance between the soft magnetic layer and the magnet, a strong magnetic fixation will be obtained. The magnet can be a permanent magnet or an electromagnet.

[0008] Such a slit will prevent unwanted eddy currents in the soft magnetic layer. By having one slit per two holes, the soft magnetic layer can be kept together as one piece. When more slits extend from one hole to a number of adjacent holes, the soft magnetic layer will be separated in several pieces. In such a case the soft magnetic layer can be attached to a substrate.

[0009] An embodiment of the electronic device according to the invention is characterized in that the primary coil and the hole are round, wherein the diameter of the hole is at least 10% and preferably 25% larger than the diameter of the primary coil.

[0010] Due to the difference in diameter, eddy currents in the soft magnetic layer are effectively prevented.

[0011] Another embodiment of the electronic device according to the invention is characterized in that the hole in the soft magnetic layer is a through hole.

[0012] Such a through hole can easily be provided in the soft magnetic layer. A substrate can be positioned on a side of the soft magnetic layer facing away from the electronic module, wherein the primary coil is being supported by the substrate.

[0013] Yet another embodiment of the electronic device according to the invention is characterized in that the hole in the soft magnetic layer is a blind hole.

[0014] A better magnetic coupling can be obtained in this manner. In such a case the backside of the primary coil is preferably shielded to prevent eddy currents in the remaining part of the soft magnetic layer in the blind hole. The blind hole can also be partly filled with a soft magnetic material suitable for alternating magnetic fields, like ferrite or a ferrite polymer compound (FPC).

[0015] A further embodiment of the electronic device according to the invention is characterized in that the soft magnetic layer comprises at least one slit extending from the hole.

[0016] When providing the soft magnetic layer with slits, the difference in diameter between the hole and the primary coil can be reduced. By reducing said difference, more surface area of the soft magnetic layer is available for attaching the magnet thereto.

[0017] Yet a further embodiment of the electronic device according to the invention is characterized in that the soft magnetic layer comprises a number of slits extending radially from the hole.

[0018] Since the radially extending slits are arranged perpendicularly to the path of the eddy currents which would flow in the absence of the slits, an optimal reduction of the eddy currents is obtained.

[0019] Yet a further embodiment of the electronic device according to the invention is characterized in that the dimensions of the primary coil and the secondary coil are about the same.

[0020] As the dimensions of the primary coil and the secondary coil are about the same, such as the same diameter, an optimal coupling factor between the primary coil and the secondary coil will be obtained.

[0021] Yet a further embodiment of the electronic device according to the invention is characterized in that the electronic module comprises at least one permanent magnet.

[0022] By using a permanent magnet instead of an electromagnet no power of the primary coil is needed for holding the electronic module against the base part. Furthermore, by using a permanent magnet the risk that the electronic module will fall off the base part in case of a power failure is easily avoided.

[0023] Preferably the permanent magnets are located around the secondary coil at a regular spacing, such that for example three permanent magnets are located in a triangle around the secondary coil or four permanent magnets are located in a square around the secondary coil to easily align the secondary coil of the electronic module with one of the primary coils of the base part.

[0024] Yet a further embodiment of the electronic device according to the invention is characterized in that the permanent magnet is magnetized normal to the soft magnetic layer.

[0025] With such a direction of the magnetic field of the permanent magnet a good magnetic fixation can be obtained with relatively small magnets.

BRIEF DESCRIPTION OF THE DRAWINGS



[0026] The invention will be explained in more detail with reference to the drawing, in which:

Fig. 1A-1C are a top view and cross sections of a first embodiment of the electronic device according to the invention,

Fig. 2 is a side view of an electronic module of the electronic device according to the invention,

Fig. 3 is a top view of a second embodiment of a base part of the electronic device according to the invention,

Fig. 4 is a top view of a third embodiment of a base part of the electronic device according to the invention,

Fig. 5 is a top view of a fourth embodiment of a base part of the electronic device according to the invention.


DETAILED DESCRIPTION OF EMBODIMENTS



[0027] In the figures, like parts are indicated with the same numerals.

[0028] Figures 1A-1C show a first embodiment of an electronic device 1 according to the invention. The electronic device 1 comprises a base part 2 and an electronic module 3.

[0029] The base part 2 comprises a non-conducting and non-magnetic substrate 4 like a printed circuit board (PCB) kind of substrate, a soft magnetic layer 5 provided with a number of through holes 6 and a number of primary coils 7. The soft magnetic layer 5 is preferably 0,5 - 2 mm thick, whereas the primary coil 6 is preferably 0,2 - 2 mm thick. Each primary coil 7 is located in a hole 6 and is mounted on the substrate 4. The holes 6 are arranged in an array with rows and columns.

[0030] The electronic module 3 comprises a secondary coil 8 and four permanent magnets 9 positioned in a square around the secondary coil 8. The secondary coil 8 and the permanent magnets 9 are mounted on a substrate 10. The hole 6, the primary coil 7 and the secondary coil 8 are round. The radii rc of the primary coil 7 and the secondary coil 8 are almost identical, whereas the radius rh of the hole 6 is about 1,1 to 1,25 times the radius rc to prevent unwanted eddy currents. The radius rc is about 10 cm. The distance between the holes 6 is about 1 cm.

[0031] The soft magnetic layer 5 is preferably made of an electrically conducting material such as a ferromagnetic material like iron or construction steel (ST7).

[0032] Figure 2 shows a side view of an electronic module 3 according to the invention comprising a secondary coil 8 and four permanent magnets 9 mounted on one side of a substrate 10 and electronic components 11 and an electronic element like a light emitting diode (LED) 12 mounted on the other side of the substrate 10. The electronic components 11 and the LED 12 are electrically connected to the secondary coil 8. The electronic module 3 may also comprise means for shielding the environment against the magnetic field to comply with EMC requirements. The permanent magnets 9 are magnetized normal to the substrate 10 and normal to the soft magnetic layer 5 in use.

[0033] When mounting the electronic module 3 on the base part 2 the permanent magnets 9 will be attracted by magnetic force to the soft magnetic layer 5 and hold the electronic module 3 against the base part 2. Since the permanent magnets 9 are located around the secondary coil 8 and the soft magnetic layer 5 is located around the primary coils 7, the secondary coil 8 will be automatically align with respect to one of the primary coils 7. The primary coils 7 are connected to a driver which can drive the primary coils 7 with an AC field, preferably in the range of 0,1 MHz - 10 MHz. The driver may include a detection mechanism to sense whether a secondary coil 8 is present opposite a primary coil 7 to activate this primary coil 7 at high power.

[0034] Figure 3 shows a top view of a second embodiment of a base part 22 of an electronic module according to the invention. The base part 22 comprises a substrate 4, a soft magnetic layer 25 provided with a number of holes 6 and a number of primary coils 7. Between pairs of holes 6 a slit 26 extends. The slit 26 can be manufactured in the soft magnetic layer 25 by means of mechanical tooling like milling or sawing, etched using photolithography or cut by a laser.

[0035] The slit 26 is provided to prevent that eddy currents occur when the primary coil 7 is powered. Such eddy currents will limit the efficiency of energy transfer to the secondary coil 8 and will generate heat in the soft magnetic layer 25.

[0036] By having one slit 26 per two holes 6, the number of slits 26 is limited and will hardly influence the mechanical strength of the soft magnetic layer 25.

[0037] Figure 4 shows a top view of a third embodiment of a base part 32 of an electronic module according to the invention. The base part 32 comprises a substrate 4, a soft magnetic layer 35 provided with a number of holes 6 and a number of primary coils 7. Between each hole 6 and its adjacent holes 6 a slit 26 extends, which divides the soft magnetic layer 35 in several pieces. The pieces of the soft magnetic layer 35 are mounted on the substrate 4. Due to the larger number of slits near each primary coil 7, eddy currents are prevented even better.

[0038] Figure 5 shows a top view of a fourth embodiment of a base part 42 of an electronic module according to the invention. The base part 42 comprises a substrate 4, a soft magnetic layer 45 provided with a number of holes 6 and a number of primary coils 7. Between each hole 6 and its adjacent holes 6 a slit 26 extends, which divides the soft magnetic layer 45 in several pieces. The pieces of the soft magnetic layer 35 are mounted on the substrate 4. Furthermore a large number of relatively short, radially extending slits 46 are provided around each hole 6.

[0039] Due to the slits 46 the occurrence of unwanted eddy currents is further reduced. These slits 46 have nearly no influence on the function of the permanent magnets 9 because the magnet flux can still flow in the direction of the remaining soft magnetic material of the soft magnetic layer 45.

[0040] The better eddy currents are being prevented by means of the slits, the smaller the difference in diameter between the primary coil 7 and the hole 6 can be.

[0041] It is also possible to provide soft magnetic material in the centre of the primary coil 7 and to provide the electronic module 3 with a centrally located permanent magnet 9.

[0042] It is also possible to use square coils or other shaped coils. In such a case, the hole has preferably the same shape as the primary coil.

[0043] It is possible to provide the base part 2 with a non magnetic cover layer to hide the primary coils from view.

[0044] It is also possible to have more than one primary coil in each hole.

[0045] It is also possible to use more or less than four magnets or to use a ring shaped magnet.

[0046] It is also possible to make the soft magnetic layer out of a number of small pieces of soft magnetic material being positioned between and near the primary coils.

[0047] It is also possible to use electromagnets instead of one or more permanent magnets, which electromagnets can be powered by the secondary coil.

[0048] Instead of a LED 12, the electronic module 3 may comprise any other kind of electronic element which can be powered by means of the secondary coil, like an OLED or a small camera, speaker, sensor, electric fan, radio device, antenna, LCD display etcetera.


Claims

1. An electronic device (1) being provided with at least a base part (2, 22, 32, 42) and an electronic module (3), which base part (2, 22, 32, 42) comprises a soft magnetic layer (5, 25, 35, 45) and at least a primary coil (7), whereas the electronic module (3) comprises at least one electronic element (11, 12) and at least a secondary coil (8) adapted to inductively interact with the primary coil (7), wherein the electronic module (3) further comprises at least one magnet (9) adapted to magnetically interact with the soft magnetic layer (5, 25, 35, 45), characterized in that the soft magnetic layer (5, 25, 35, 45) is provided with a number of primary coils (7) located in holes (6), wherein at least one slit extends between adjacent holes (6).
 
2. An electronic device (1) according to claim 1, characterized in that the primary coil (7) and the hole (6) are round, wherein the diameter of the hole (6) is at least 10% and preferably 25% larger than the diameter of the primary coil (7).
 
3. An electronic device (1) according to claim 1 or 2, characterized in that the hole (6) in the soft magnetic layer (5, 25, 35, 45) is a through hole (6).
 
4. An electronic device (1) according to claim 1 or 2, characterized in that the hole in the soft magnetic layer (5, 25, 35, 45) is a blind hole.
 
5. An electronic device (1) according to any one of the preceding claims, characterized in that the soft magnetic layer (5, 25, 35, 45) comprises a number of slits extending radially from the hole (6).
 
6. An electronic device (1) according to any one of the preceding claims, characterized in that the dimensions of the primary coil (7) and the secondary coil (8) are about the same.
 
7. An electronic device (1) according to any one of the preceding claims, characterized in that the electronic module (3) comprises at least one permanent magnet (9).
 
8. An electronic device (1) according to claim 7, characterized in that the electronic module (3) comprises at least three permanent magnets (9) located around the secondary coil (8) at a regular spacing.
 
9. An electronic device (1) according to claim 7 or 8, characterized in that three permanent magnets (9) are located in a triangle around the secondary coil.
 
10. An electronic device (1) according to claim 7 or 8, characterized in that four permanent magnets (9) are located in a square around the secondary coil.
 
11. An electronic device (1) according to any one of the claims 7 to10, characterized in that the permanent magnet (9) is magnetized normal to the soft magnetic layer (5, 25, 35, 45).
 


Ansprüche

1. Ein Elektronikgerät (1), das mit mindestens einem Unterteil (2, 22, 32, 42) und einem Elektronikmodul (3) bereitgestellt wird, wobei das Unterteil (2, 22, 32, 42) eine weichmagnetische Schicht (5, 25, 35, 45) und mindestens eine Primärspule (7) umfasst, während das Elektronikmodul (3) mindestens ein elektronisches Element (11, 12) und mindestens eine Sekundärspule (8) umfasst, die darauf ausgelegt ist, induktiv mit der Primärspule (7) zu interagieren,
wobei das Elektronikmodul (3) ferner mindestens einen Magnet (9) umfasst, der darauf ausgelegt ist, magnetisch mit der weichmagnetischen Schicht (5, 25, 35, 45) zu interagieren, dadurch gekennzeichnet, dass die weichmagnetische Schicht (5, 25, 35, 45) mit einer Anzahl in Löchern (6) angeordneter Primärspulen (7) bereitgestellt wird, wobei sich zwischen benachbarten Löchern (6) mindestens ein Schlitz befindet.
 
2. Ein Elektronikgerät (1) nach Anspruch 1, dadurch gekennzeichnet, dass die Primärspule (7) und das Loch (6) rund sind, wobei der Durchmesser des Lochs (6) mindestens 10 % und bevorzugt 25 % größer als der Durchmesser der Primärspule (7) ist.
 
3. Ein Elektronikgerät (1) nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Loch (6) in der weichmagnetischen Schicht (5, 25, 35, 45) ein Durchgangsloch (6) ist.
 
4. Ein Elektronikgerät (1) nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Loch in der weichmagnetischen Schicht (5, 25, 35, 45) ein blindes Loch ist.
 
5. Ein Elektronikgerät (1) nach einem der obigen Ansprüche, dadurch gekennzeichnet, dass die weichmagnetische Schicht (5, 25, 35, 45) eine Anzahl Schlitze umfasst, die sich radial von dem Loch (6) erstrecken.
 
6. Ein Elektronikgerät (1) nach einem der obigen Ansprüche, dadurch gekennzeichnet, dass die Abmessungen der Primärspule (7) und der Sekundärspule (8) in etwa gleich sind, dadurch gekennzeichnet.
 
7. Ein Elektronikgerät (1) nach einem der obigen Ansprüche, dadurch gekennzeichnet, dass das Elektronikmodul (3) mindestens einen Dauermagnet (9) umfasst.
 
8. Ein Elektronikgerät (1) nach Anspruch 7, dadurch gekennzeichnet, dass das Elektronikmodul (3) mindestens drei Dauermagnete (9) umfasst, die gleichbeabstandet um die Sekundärspule (8) angeordnet sind.
 
9. Ein Elektronikgerät (1) nach Anspruch 7 oder 8, dadurch gekennzeichnet, dass drei Dauermagnete (9) in einem Dreieck um die Sekundärspule angeordnet sind.
 
10. An Elektronikgerät (1) nach Anspruch 7 oder 8, dadurch gekennzeichnet, dass vier Dauermagnete (9) in einem Viereck um die Sekundärspule angeordnet sind.
 
11. Ein Elektronikgerät (1) nach einem der Ansprüche 7 bis 10, dadurch gekennzeichnet, dass der Dauermagnet (9) zu der weichmagnetischen Schicht (5, 25, 35, 45) normal magnetisiert ist.
 


Revendications

1. Dispositif électronique (1) pourvu d'au moins une partie de base (2, 22, 32, 42) et d'un module électronique (3), laquelle partie de base (2, 22, 32, 42) comprend une couche faiblement magnétique (5, 25, 35, 45) et au moins une bobine primaire (7), alors que le module électronique (3) comprend au moins un élément électronique (11, 12) et au moins une bobine secondaire (8) adaptée pour interagir par induction avec la bobine primaire (7), dans lequel
le module électronique (3) comprend en outre au moins un aimant (9) adapté pour interagir magnétiquement avec la couche faiblement magnétique (5, 25, 35, 45), caractérisé en ce que la couche faiblement magnétique (5, 25, 35, 45) est pourvue d'un nombre de bobines primaires (7) situées dans des trous (6), dans lequel au moins une fente s'étend entre des trous adjacents (6).
 
2. Dispositif électronique (1) selon la revendication 1, caractérisé en ce que la bobine primaire (7) et le trou (6) sont ronds, dans lequel le diamètre du trou (6) est supérieur d'au moins 10 % et de préférence 25 % au diamètre de la bobine primaire (7).
 
3. Dispositif électronique (1) selon la revendication 1 ou 2, caractérisé en ce que le trou (6) dans la couche faiblement magnétique (5, 25, 35, 45) est un trou débouchant (6).
 
4. Dispositif électronique (1) selon la revendication 1 ou 2, caractérisé en ce que le trou dans la couche faiblement magnétique (5, 25, 35, 45) est un trou borgne.
 
5. Dispositif électronique (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que la couche faiblement magnétique (5, 25, 35, 45) comprend un nombre de fentes s'étendant radialement à partir du trou (6).
 
6. Dispositif électronique (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que les dimensions de la bobine primaire (7) et de la bobine secondaire (8) sont environ les mêmes.
 
7. Dispositif électronique (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que le module électronique (3) comprend au moins un aimant permanent (9).
 
8. Dispositif électronique (1) selon la revendication 7, caractérisé en ce que le module électronique (3) comprend au moins trois aimants permanents (9) situés autour de la bobine secondaire (8) à un espacement régulier.
 
9. Dispositif électronique (1) selon la revendication 7 ou 8, caractérisé en ce que trois aimants permanents (9) sont situés en un triangle autour de la bobine secondaire.
 
10. Dispositif électronique (1) selon la revendication 7 ou 8, caractérisé en ce que quatre aimants permanents (9) sont situés en un carré autour de la bobine secondaire.
 
11. Dispositif électronique (1) selon l'une quelconque des revendications précédentes 7 à 10, caractérisé en ce que l'aimant permanent (9) est magnétisé de façon normale à la couche faiblement magnétique (5, 25, 35, 45).
 




Drawing














Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description