JP5918563B2 - Non-contact power transmission device - Google Patents

Description

  The present invention relates to a non-contact power transmission apparatus that transmits power in a non-contact (wireless) manner.

  As a method of transmitting power in a non-contact manner, an electromagnetic induction type by electromagnetic induction (several hundreds of kHz), an electric field / magnetic field resonance type by transmission between LC resonances via electric field or magnetic field resonance, a microwave power transmission type by radio waves (several GHz), Alternatively, a laser power transmission type using electromagnetic waves (light) in the visible light region is known. Among them, the electromagnetic induction type has already been put into practical use. This has the advantage that it can be realized with a simple circuit (transformer system), but there is also a problem that the transmission distance is short.

  Therefore, recently, electric field / magnetic field resonance type power transmission capable of short-distance transmission (up to 2 m) has attracted attention. Among these, in the case of the electric field resonance type, when a hand or the like is put in the transmission path, the human body is a dielectric, so that energy is absorbed as heat and dielectric loss occurs. On the other hand, in the case of the magnetic resonance type, the human body hardly absorbs energy, and dielectric loss can be avoided. From this point of view, attention to the magnetic resonance type has been increasing.

  The contactless power transmission / reception method using such an electromagnetic induction type or magnetic field resonance type configuration enables non-contact charging, and thus it is necessary to expose a terminal for receiving power in the power receiving device on the surface. Disappear. As a result, it is possible to realize a device with improved safety and convenience by eliminating the concern of contamination due to contamination on the terminals and failure of electric leakage or electric shock from the exposed terminals. In particular, in the magnetic resonance type configuration, since the degree of freedom with respect to the relative position of the power receiving device of the power transmitting device is large, the convenience for the user is great.

  However, a non-contact power transmission device using a general magnetic field resonance has a drawback that electromagnetic waves easily leak outside the non-contact power transmission device. Since leakage of electromagnetic waves causes malfunction of peripheral devices, it is necessary to provide means for suppressing leakage of electromagnetic waves. It is known that a shield structure that covers a housing of a non-contact power transmission apparatus with a conductor or the like is effective as a means for suppressing leakage of electromagnetic waves. Patent Document 1 discloses a contactless power transmission device having a shield structure.

  Furthermore, if one power transmission device can transmit power to different types of power reception devices, the convenience is further improved. In that case, since it is necessary to transmit power under optimum conditions for each form of the power receiving apparatus, it is desirable that the power transmitting apparatus can automatically determine the form of the power receiving apparatus. Patent Document 2 discloses a device that transmits power from a power transmission device to a plurality of power reception devices under optimal power transmission conditions. Specifically, a dedicated cradle is prepared according to the form of the power receiving apparatus, and an individual identifier is provided for the cradle. The power transmission device reads the individual identifier to identify the form of the power reception device, and automatically changes the power transmission condition of the power transmission device to a condition suitable for the power reception device.

JP 2012-19648 A JP 2009-219203 A

  In the case of transmitting power from a power transmission device to a plurality of power receiving devices, the function of automatically detecting the form of the power receiving device is important, but at the same time, while ensuring the shielding characteristics of electromagnetic waves, the user can It is desirable to be able to visually recognize a power receiving device installed inside and receiving power.

  First, although the structure disclosed in Patent Document 1 can shield electromagnetic waves, a user cannot visually recognize a power receiving device that is installed inside the device during power transmission.

  The device described in Patent Document 2 can transmit power from a power transmission device to a plurality of power reception devices under optimal power transmission conditions, but is in a state where the power transmission device and the power reception device are in contact with each other. The positional relationship of is constant. On the other hand, in a method of transmitting and receiving power without contact, for example, a magnetic field resonance method with a large degree of freedom in the position of the power transmission device with respect to the power reception device, even if the position of a plurality of power reception devices changes, the optimum It must be possible to transmit power under the transmission conditions.

  Furthermore, it is important to realize a non-contact power transmission device that can operate regardless of location, such as the presence or absence of an external power supply. Since an object to be charged by contactless power transmission can be charged contactlessly, a connector for charging is unnecessary, and thus complete waterproofing can be easily realized. Therefore, many objects to be charged by non-contact power transmission are assumed to be used outdoors, and it is required to be able to charge outdoors as well as indoors.

The contactless power transmission device of the present invention is
A power transmission device having a power transmission resonator composed of a power transmission coil and a resonant capacitor;
Non-contact power including a power receiving device having a power receiving resonator including a power receiving coil and a resonance capacitor, and transmitting power from the power transmitting device to the power receiving device via an AC electromagnetic field between the power transmitting coil and the power receiving coil In transmission equipment,
A power transmission auxiliary device having an auxiliary resonator constituted by an auxiliary coil and a resonant capacitor;
In a state where the power transmission auxiliary device and the power transmission device are arranged to face each other, a power reception space for arranging the power reception coil is formed between the power transmission coil and the auxiliary coil,
A housing containing the power transmission device, the power receiving device, and the power transmission auxiliary device;
The electromagnetic wave based on the alternating electromagnetic field when transmitting electric power is transmitted from the power transmission device to the power receiving device in a state where the entire housing is electromagnetically shielded so as not to leak to the outside of the housing,
Of the power transmission coil and the auxiliary coil, the inner dimension / outer dimension ratio of the auxiliary coil is 0.6 or more and the inner dimension / outer dimension ratio of the coil of power transmission is 0.4 or less, or , the power transmission coil and the inner dimension / outer dimensions ratio of the coils of both of the auxiliary coil is the same, and, in the power transmission coil and the inner dimension / outer dimensions ratio of the auxiliary coil 0.4 or more, It is 0.6 or less .

  According to the present invention, in the non-contact power transmission device, the range in which the amount of power received by the power receiving device is constant can be expanded, and the visibility of the power receiving device can be improved.

  The power receiving device is stored in an individual tray provided in the power transmission device, and the tray is configured to be detachable from the power transmission device. By adopting such a configuration, it is possible to transmit power to a plurality of types of power receiving devices with a single power transmitting device, and the convenience for the user is improved.

  Furthermore, according to the present invention, since a compact DC power source is used as a power source for non-contact power transmission, the non-contact power transmission device can be carried outdoors, and non-contact power transmission is possible even outdoors.

The perspective view which shows the external appearance of the non-contact electric power transmission apparatus in Embodiment 1. The perspective view which shows the whole power transmission apparatus inside of the non-contact power transmission apparatus The perspective view which shows the shield structure inside the power transmission apparatus of the non-contact electric power transmission apparatus The perspective view which shows the window member inside the power transmission apparatus of the non-contact electric power transmission apparatus The perspective view which shows the tray detector inside the power transmission apparatus of the non-contact power transmission apparatus The perspective view which shows arrangement | positioning of the tray detector and tray detection part inside the power transmission apparatus of the non-contact electric power transmission apparatus The perspective view which shows the tray form a of the non-contact electric power transmission apparatus The perspective view which shows the tray form b of the non-contact electric power transmission apparatus The perspective view which shows the tray form c of the non-contact electric power transmission apparatus The top view which shows the auxiliary coil form inside the power transmission apparatus of the same non-contact power transmission apparatus The top view which shows the power transmission coil form inside the power transmission apparatus of the non-contact power transmission apparatus Characteristic diagram showing power transmission efficiency position dependency of non-contact power transmission equipment The perspective view which shows the external appearance of the non-contact electric power transmission apparatus in Embodiment 2. Explanatory drawing which shows the characteristic of an Example and a comparative example The perspective view which shows the form of the internal substrate which mounted DC power supply of the non-contact electric power transmission apparatus in Embodiment 3. Sectional drawing which shows the whole inside of the non-contact electric power transmission apparatus in Embodiment 3. The perspective view which shows the form which mounted DC power supply outside the non-contact electric power transmission apparatus in Embodiment 3. Explanatory drawing showing the definition of inner and outer dimensions of various coil shapes

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
FIG. 1 is a perspective view of the appearance of the non-contact power transmission apparatus according to the first embodiment. The non-contact power transmission device 1 includes a power transmission device main body 100, a power transmission device lid 200, and a hinge 190 that connects them.

  The power transmission device main body 100 is covered with a power transmission device main body cover 101 made of a resin material, and a power transmission device main body shield 102 made of a copper plate material is formed therein. Furthermore, there is a power transmission device tray 120 made of a resin material that houses the power reception device 300.

  The power transmission device lid 200 is covered with a power transmission device lid cover 201 made of a resin material, and a power transmission device lid shield 202 made of a copper plate material is formed therein. Furthermore, a power transmission device viewing window shield 203 made of a wire mesh made of a laminate of nickel and copper is formed at the center.

  FIG. 2 is a perspective view of the appearance when the power transmission device main body cover 101, the power transmission device tray 120, and the power transmission device lid cover 201 are removed from the state of FIG.

  A power transmission coil 110 is housed inside the power transmission device main body shield 102. As shown in FIG. 11, the power transmission coil has a power transmission coil substrate 112 formed on a power transmission coil substrate 111, and a radio wave absorber 113 is disposed on the back surface of the power transmission coil substrate. Although not shown, both ends of the power transmission coil wire are connected to a coil drive circuit. Further, a resonance capacitor is connected to the power transmission coil to constitute a power transmission resonator. As the resonance capacitance, a variable capacitor or a fixed capacitor may be connected as a circuit element, or a configuration using a stray capacitance may be used. Therefore, the illustration of the resonance capacitance is omitted in the following drawings.

The coil wire 112 is made of copper and has an inner dimension of about 30% with respect to the outer dimension of the coil wire, and has a generally rectangular spiral shape and is wound in a relatively coarse manner. Note that the inner dimension and the outer dimension of the coil are respectively determined according to the variation of the coil shape shown in FIG. Specifically, it is as follows.
(1) In the case of a square or a rectangle Inner dimension: the shortest distance among the coil centerline distances between the opposing short sides Outer dimension: The direction parallel to the inner dimension among the coil centerline distances between the opposing sides Longest distance at (2) In the case of a polygon Internal dimension: Distance between the innermost coil centerline of the coil innermost part of the coil The distance between the innermost coil centerline of the coil External dimension: The part of the coil facing the coil centerline Longest distance in the direction parallel to the inner dimension among the distances between the coil center lines (3) In the case of a circular spiral Inner dimension: Diameter of the circle inscribed in the coil center line (the wavy line in the figure corresponds to the inscribed circle)
Outer dimension: Distance between coil center lines, longest distance in the direction parallel to the inner dimension (4) In the case of an elliptical spiral Inner dimension: Shortest distance between coil center distances corresponding to the major axis direction of the ellipse Outer dimension: Coil center The longest distance in the direction parallel to the inner dimension in the line-to-line distance Note that the inner and outer dimensions of the coil can be defined using the same method even for coil shapes other than those shown in FIG. .

  A lid opening / closing detector 130 for detecting opening / closing of the power transmission device lid 200 is installed inside the power transmission device main body shield 102. The closure of the power transmission device lid 200 is detected by the lid open / close detector 130, and after the shield structure is established, a current is passed through the power transmission coil 110 and power is supplied to the power reception device in a contactless manner. The

  An auxiliary coil 210 is installed inside the power transmission device lid shield 202. As shown in FIG. 10, the auxiliary coil 210 has an auxiliary coil wire 212 spirally wound on a substantially rectangular shape on an auxiliary coil substrate 211, and a radio wave absorber 213 disposed on the back surface of the auxiliary coil substrate 211. Has been. In addition, the coil wire 212 is wound in a relatively dense winding manner with an inner dimension of about 70% of the outer dimension of the coil wire and a generally rectangular spiral shape. Furthermore, a substantially rectangular auxiliary coil substrate opening 214 is formed at the center of the coil substrate 211. A resonance capacitor is connected to the auxiliary coil to constitute an auxiliary power transmission resonator. As the resonance capacitance, a variable capacitor or a fixed capacitor may be connected as a circuit element, or a configuration using a stray capacitance may be used. Therefore, the illustration of the resonance capacitance is omitted in the following drawings.

  The auxiliary coil is the one disclosed by the inventors in Japanese Patent Application No. 2011-283803, which is a prior application.

  That is, a power transmission device having a power transmission resonator constituted by a power transmission coil and a resonance capacitor, and a power reception device having a power reception resonator constituted by a power reception coil and a resonance capacitance, the power transmission coil and the power reception device are used. In the method of transmitting electric power from the power transmission device to the power receiving device via an alternating electromagnetic field between coils, a power transmission auxiliary device having an auxiliary resonator newly configured by a coil and a resonance capacitor is further used, and the power transmission auxiliary A device is disposed opposite to the power transmission device, and the power reception coil is disposed in a power reception space formed between the power transmission coil and the newly added coil to perform power transmission. The added coil is called an auxiliary coil.

  Next, for the sake of explanation, FIG. 3 shows a state in which only the power transmission device main body shield 102 and the power transmission device lid shield 202 are taken out from the non-contact power transmission device 1 and the lid is closed. As shown in the figure, the power transmission device main body shield 102 and the power transmission device lid shield 202 have a structure in which the power transmission device main body shield end portion 105 and the power transmission device lid shield end portion 205 are brought into contact with each other. As a result, good electrical conduction is ensured. Further, the power transmission device shield viewing window opening 204 is covered with a power transmission device viewing window shield 203 formed of a wire mesh made of a nickel-copper laminated material shown in FIG.

  The window shield has a structure in which a magnetic field is effectively cut off from nickel, which is a soft magnetic material, and an electric field is effectively cut off from copper, which is a good conductor.

  As is apparent from the above, the inside of the non-contact power transmission device 1 is shielded by the power device main body shield 102, the power transmission device lid shield 202, and the power transmission device viewing window shield 203 other than the power transmission device shield viewing window opening 204. The electromagnetic wave generated inside is shielded.

  Members stored inside the power transmission apparatus main body shield 102 are shown in FIGS. 5 and 6. A tray storage unit 150 is stored inside the power transmission device main body shield 102, and a power transmission device tray 120 for storing the power receiving device 300 is stored therein.

  Further, the power transmission coil 110, the shielding plate 180, and the circuit boards 160 and 170 are arranged in the lower part of the tray storage unit 150 via spacers between the respective members.

  The lower part of the circuit board 170 is connected to the power transmission apparatus main body shield 102 (not shown here) via a spacer.

  As shown in FIG. 5, reflection type photo interrupters 1611, 1612, and 1613 are arranged on the right end of the circuit board 160, and are formed on the back surface of the tray 120 through the tray opening 151 provided in the tray storage unit 150. The identifier 121 is recognized.

  As shown in FIGS. 7, 8, and 9, the trays 1201, 1202, and 1203 are connected to the same power transmission device main body 100, and the power receiving devices 301 (hearing aids), 302 (music players), and 303 (digital cameras). At the same time, each of the lower trays is provided with a different identifier as shown at 1211, 1212 and 1213.

  The non-contact power transmission device 1 is configured to recognize the unique identifier provided in the lower part of the tray, thereby switching the characteristics of the power transmission circuit and transmitting power suitable for the power receiving target.

  The identifier is formed by three patterns of high and low reflectivity. The low reflectivity part has a 3-bit pattern configuration corresponding to 0 and the high reflectivity part corresponds to 1. In addition, as a bit configuration, a bit pattern in which all of them are the same, for example, 000 or 111 patterns is prohibited, and a pattern configuration in which one pattern is always in two places in three bits.

  With the above configuration, if the photo interrupter 1611, 1612, 1613 breaks down or the specific place of the identifier gets dirty and misreads the original 0 or 1, it will result in a pattern other than the above. , Can prevent misrecognition. In the present invention, since the tray and the power receiving target are three types as shown in FIGS. 7, 8, and 9, the above pattern rule is used. However, in order to recognize more types of patterns, a recognition bit is used. The number can be increased, or the redundancy can be reduced to some extent, but the prohibition pattern can be changed to 000 and 111 only.

  In the present embodiment, the auxiliary coil 210 is provided in the power transmission device lid 200 and the power transmission coil 110 is provided in the power transmission device main body 100. However, the power transmission coil and the auxiliary coil may be interchanged. That is, the auxiliary coil 210 may be provided in the power transmission device main body 100 and the power transmission coil 110 may be provided in the power transmission device lid 200. However, when the power transmission coil 110 is disposed in the power transmission device lid 200, it is necessary to separately wire the coil from a coil drive circuit (not shown) to the power transmission coil 110 disposed in the power transmission device lid 200 using an FPC or the like. .

<Embodiment 2>
FIG. 13 is a perspective view showing the appearance of the non-contact power transmission apparatus in the second embodiment. Unlike the first embodiment, the power transmission coil and the auxiliary coil are provided on the vertical wall of the power transmission apparatus main body 100. The auxiliary coil is provided on the wall side where the power transmission apparatus main body side viewing window 603 is provided, and the power transmission coil is provided on the wall side facing the wall where the auxiliary coil is provided.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

<Embodiment 3>
Embodiment 3 shows a case where a DC power source is used as a power source for non-contact power transmission. FIG. 15 shows a case where the DC power source 173 of the non-contact power transmission device is mounted on the circuit board 170 of the non-contact power transmission device. The DC power supply 173 is installed in a form that fits into a power supply holder 174 provided on the circuit board 170. As the DC power source, a battery pack made of a secondary battery can be used. The connector 175 is a connector for charging power from the outside to the secondary battery.

  FIG. 16 is a cross-sectional view showing the entire inside of the non-contact power transmission device in which the DC power source 173 is built.

  When a built-in DC power source is used as a power source for contactless power transmission, the contactless power transmission device can be carried outdoors and contactless power transmission can be performed outdoors. In fact, since an object to be charged by non-contact power transmission can be charged in a non-contact manner, a connector for charging is unnecessary, so that complete waterproofing can be easily realized. For this reason, many objects to be charged by non-contact power transmission are premised on outdoor use, and it is required that charging be possible outdoors.

  According to this embodiment, since DC power supply 173 is built in the non-contact power transmission device, non-contact power transmission can be realized both indoors and outdoors, regardless of the presence or absence of an external power source.

  Note that the DC power supply may be provided outside the non-contact power transmission device. FIG. 17 shows a case where a DC power source 800 is provided outside the non-contact power transmission device 4 and the power transmission device 4 and the DC power source 800 are connected using a connection cable 801. Even when the DC power source is provided outside the non-contact power transmission device, if the non-contact power transmission device and the DC power source are carried together, the non-contact power transmission can be performed regardless of the location. Since the DC power supply exists outside the contactless power transmission device, the contactless power transmission device can be easily downsized.

Hereinafter, in Embodiment 1 described above, the result of studying the amount of power received by the power receiving device from the power transmitting device and the power transmitting auxiliary device while changing the shapes of the power transmitting coil and the auxiliary coil will be described.
<Example 1>
In Example 1, the inner shape of the power transmission coil was set to 0.3 with respect to the outer shape, and the inner shape of the auxiliary coil was set to 0.7 of the outer shape.
<Example 2>
In Example 2, the inner shape of the power transmission coil was set to 0.5 with respect to the outer shape, and the inner shape of the auxiliary coil was set to 0.5, which is the outer shape.
<Example 3>
In Example 3, the inner shape of the power transmission coil was set to 0.4 with respect to the outer shape, and the inner shape of the auxiliary coil was set to 0.4 of the outer shape.
<Example 4>
In Example 4, the inner shape of the power transmission coil was set to 0.6 with respect to the outer shape, and the inner shape of the auxiliary coil was set to 0.6, which is the outer shape.
<Comparative Example 1>
In Comparative Example 1, the inner shape of the power transmission coil was 0.7 with respect to the outer shape, and the inner shape of the auxiliary coil was 0.7, which is the outer shape.
<Comparative Example 2>
In Comparative Example 2, the inner shape of the power transmission coil was set to 0.3 with respect to the outer shape, and the inner shape of the auxiliary coil was set to 0.3, which is the outer shape.

  FIG. 6 shows the X direction dependency of the amount of power received by the power receiving device from the power transmitting device and the power transmission auxiliary device. The X direction refers to the long axis direction of the receiving coil from the center of the receiving coil. The amount of power received is shown relatively, and the dependence of the relative amount of power received in the X direction was shown for each of Examples 1 to 4 and Comparative Examples 1 and 2.

  As can be seen from the figure, when the length of the long axis of the substantially rectangular power transmission coil is 2 A, in the case of Examples 1 to 4, the power reception amount is substantially constant from the center to about 0.5 A in the outer direction of the power reception coil. Has been realized. Outside 0.5A, the amount of power received gradually decreases, and the amount of power received becomes zero at a point of 1A corresponding to the outer diameter on the coil long axis side.

  Although not shown, this tendency is the same even in the short axis direction of the coil. When the length of the short axis is 2B, the received power amount is constant up to about 0.5B, and the received power amount becomes 0 at the point of 1B.

  From the above, when the inner dimension / outer dimension ratio of the power transmission coil and auxiliary coil is the same, the amount of power received can be reduced by setting the inner dimension / outer dimension ratio of the power transmission coil and auxiliary coil to 0.4 or more and 0.6 or less. It was found that the uniformity can be realized. On the other hand, when one of the inner dimension / outer dimension ratio of the power transmission coil and the auxiliary coil is made larger than 0.6, it is understood that the uniformity of the amount of power received can be realized similarly by making the other smaller than 0.4. It was.

  As described above, the first to fourth embodiments have an advantage that the amount of received power is small even when the position of the power receiving coil varies because the amount of received power can be made constant in a wide area.

  Further, as shown in FIG. 2, the auxiliary coil is formed so as to surround the power transmission device shield viewing window opening, but in Examples 1 to 4, the inner shape of the auxiliary coil is larger than the outer shape of 0.4. Therefore, the power transmission device shield viewing window opening can be enlarged. As a result, the visibility of the power receiving device mounted on the power transmission device tray during power transmission is improved.

  On the other hand, even in the case of Comparative Example 1, since the inner shape of the auxiliary coil is larger than the outer shape of 0.4, the power transmission device shield viewing window opening can be enlarged. However, the amount of power received is low at the center of the power receiving coil, and the amount of power received becomes maximum at 0.6A outward from the center of the coil. The amount of power received becomes 0 at a point of 1A corresponding to the outer diameter.

  In the case of Comparative Example 2, the amount of power received is large at the center of the power receiving coil, and the amount of power received decreases outward from 0.2 A outward from the center of the coil, and 1 A corresponding to the outer diameter on the coil major axis side. The amount of power received at the point becomes zero. Since the inner shape of the auxiliary coil is 0.4 or less of the outer shape, the power transmission device shield viewing window opening cannot be enlarged.

  The above results are summarized in FIG. In Example 1 and Example 2, it turns out that the uniformity of the amount of received electric power and the visibility of a power receiving apparatus can be made compatible. On the other hand, none of the comparative examples can realize the uniformity of the amount of power received.

  In addition, although the above Example is a result based on Embodiment 1, even when based on Embodiment 2 or Embodiment 3, the same result is obtained.

  According to the present invention, since the range in which the amount of power received by the power receiving apparatus is constant can be expanded, it is suitable for non-contact power transmission of small devices such as hearing aids, mobile devices such as mobile phones and digital cameras.

DESCRIPTION OF SYMBOLS 1, 2 Non-contact electric power transmission apparatus 100 Power transmission apparatus main body 200 Power transmission apparatus cover part 300,301,302,303 Power receiving apparatus 101 Power transmission apparatus main body cover 102 Power transmission apparatus main body shield 103,104 LED attachment hole 105 Power transmission apparatus main body shield edge part 110 Power transmission coil 111 Power transmission coil substrate 112 Power transmission coil wire material 113 Wave absorber 120, 620, 1201, 1202, 1203 Power transmission device tray 121, 1211, 1212, 1213 Power transmission device tray identifier 130 Cover open / close detector 140 Conductive seal 150 Tray storage 151 Tray storage bottom opening 160 circuit board 1
161 Substrate material 1611, 1612, 1613 Identifier detection device 170 Circuit board 2
180 Shield plate 171, 172 LED
190 Hinge 200, 700 Power transmission device cover 201, 701 Power transmission device cover 202, 702 Power transmission device shield 203, 703 Power transmission device viewing window shield 204 Power transmission device shield viewing window opening 205 Power transmission device cover shield end 210 Auxiliary Coil 211 Auxiliary Coil Substrate 212 Auxiliary Coil Wire 213 Radio Wave Absorber 214 Auxiliary Coil Substrate Opening 240 Conductive Seal 603 Power Transmission Device Main View Window

Claims (4)

A power transmission device having a power transmission resonator composed of a power transmission coil and a resonant capacitor;
Non-contact power including a power receiving device having a power receiving resonator including a power receiving coil and a resonance capacitor, and transmitting power from the power transmitting device to the power receiving device via an AC electromagnetic field between the power transmitting coil and the power receiving coil In transmission equipment,
A power transmission auxiliary device having an auxiliary resonator constituted by an auxiliary coil and a resonant capacitor;
In a state where the power transmission auxiliary device and the power transmission device are arranged to face each other, a power reception space for arranging the power reception coil is formed between the power transmission coil and the auxiliary coil,
A housing containing the power transmission device, the power receiving device, and the power transmission auxiliary device;
The electromagnetic wave based on the alternating electromagnetic field when transmitting electric power is transmitted from the power transmission device to the power receiving device in a state where the entire housing is electromagnetically shielded so as not to leak to the outside of the housing,
Of the power transmission coil and the auxiliary coil, the inner dimension / outer dimension ratio of the auxiliary coil is 0.6 or more and the inner dimension / outer dimension ratio of the coil of power transmission is 0.4 or less, or , the power transmission coil and the inner dimension / outer dimensions ratio of the coils of both of the auxiliary coil is a same, in its inner dimension / outer dimensions ratio 0.4 or more, and to 0.6 or less A non-contact power transmission device. At least one of the walls constituting the housing is formed with a window portion through which the power receiving device can be seen from the outside of the housing, and the window portion is electromagnetically shielded. Item 2. The non-contact power transmission device according to Item 1 . The contactless power transmission device according to claim 2 , wherein the auxiliary coil is formed so as to surround the window portion. The contactless power transmission device according to claim 2 , wherein the power transmission coil is formed so as to surround the window portion.

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