U.S. patent application number 15/299681 was filed with the patent office on 2017-02-09 for charging apparatus.
The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to Yu Hasegawa, Yukio Iijima, Masanobu Kanaya, Kazunori Yamada.
Application Number | 20170040834 15/299681 |
Document ID | / |
Family ID | 49082031 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170040834 |
Kind Code |
A1 |
Hasegawa; Yu ; et
al. |
February 9, 2017 |
CHARGING APPARATUS
Abstract
A charging apparatus is provided that avoids a reduction in the
strength of radio waves or a magnetic field used by a charging
target device having a wireless communication function and reduces
an influence on the radio waves or magnetic field. In this
apparatus, position detection section (201) detects a position of
power reception coil (251) of charging target device (150) placed
on charging table (101). Power transmission coil (208) is made
close to power reception coil (251) and transmits electric power.
Coil moving mechanism (207) brings power transmission coil (208)
close to the position of power reception coil (251) that is
detected by position detection section (201).
Inventors: |
Hasegawa; Yu; (Kanagawa,
JP) ; Kanaya; Masanobu; (Kanagawa, JP) ;
Iijima; Yukio; (Kanagawa, JP) ; Yamada; Kazunori;
(Ishikawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Family ID: |
49082031 |
Appl. No.: |
15/299681 |
Filed: |
October 21, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14005881 |
Sep 18, 2013 |
9502922 |
|
|
PCT/JP2013/000771 |
Feb 13, 2013 |
|
|
|
15299681 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 2220/20 20130101;
H02J 50/40 20160201; H01M 10/46 20130101; H02J 7/0042 20130101;
H02J 50/60 20160201; H02J 50/12 20160201; H02J 7/025 20130101; H04B
5/0037 20130101; H02J 50/90 20160201; Y02E 60/10 20130101 |
International
Class: |
H02J 7/02 20060101
H02J007/02; H02J 50/12 20060101 H02J050/12; H04B 5/00 20060101
H04B005/00; H02J 50/60 20060101 H02J050/60 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 29, 2012 |
JP |
2012-044027 |
Sep 6, 2012 |
JP |
2012-195860 |
Claims
1. A charging apparatus that transmits electrical power to a
charging target device by electromagnetic induction to charge a
secondary battery of the charging target device, the charging
apparatus comprising: a power transmission coil; a position
detection section that detects a position of a power reception coil
of the charging target device placed on the charging apparatus, the
position detection section includes a plurality of coils disposed
separately from the power transmission coil; and a near field
communication antenna that enables near field communication with
the charging target device by electromagnetic induction, wherein
the near field communication antenna is any one of the plurality of
coils of the position detection section.
2. The charging apparatus according to claim 1, further comprising:
a near field communication control section that is to be connected
to the near field communication antenna and that executes near
field communication with the charging target device; and a
switching section that switches operation between the position
detection section and the near field communication control
section.
3. The charging apparatus according to claim 1, further comprising:
a charging table in which the coils of the position detection
section are disposed on an inner surface side of the charging
table, and on which the charging target device is to be placed,
wherein a length in a short-side direction of the charging table is
greater than a length in a short-side direction of the charging
target device and is less than a sum of the length in the
short-side direction of the charging target device and an interval
of the near field communication antenna.
4. The charging apparatus according to claim 3, wherein the coils
of the position detection section are disposed at predetermined
intervals in a plurality of rows in a longitudinal direction and a
transverse direction of the charging table, and the coil of the
position detection section that is the near field communication
antenna is disposed at a center in the short-side direction among
the plurality of rows of coils of the position detection section.
Description
[0001] This is a continuation of U.S. patent application Ser. No.
14/005,881 filed on Sep. 18, 2013 which is a National Phase Entry
of International Application No. PCT/JP2013/000771 filed on Feb.
13, 2013 which claims priority from Japanese Patent Application No.
2012-195860 filed on Sep. 6, 2012 and Japanese Patent Application
No. 2012-044027 filed on Feb. 29, 2012. The contents of these
applications are incorporated herein by reference in their
entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to a charging apparatus on
which a device including therein a secondary battery is placed, and
which transmits electrical power by an electromagnetic induction
action to charge the secondary battery, the device being a charging
target.
BACKGROUND ART
[0003] Patent Literature (hereinafter, referred to as "PTL") 1
discloses a configuration in which a power reception coil is
embedded in a device to be charged, and a charging table that
detects positions of a power transmission coil and the power
reception coil is provided in a charging apparatus that transmits
electrical power.
[0004] PTL 2 discloses a contactless charging apparatus that uses a
contactless charging method to charge a cellular telephone
including a non-contact-type near field communication unit such as
a non-contact IC card, Bluetooth (registered trademark), or
infrared communication.
CITATION LIST
Patent Literatures
[0005] PTL 1 [0006] Japanese Patent Application Laid-Open No.
2011-4474 [0007] PTL 2 [0008] Japanese Patent Application Laid-Open
No. 2011-83057
SUMMARY OF INVENTION
Technical Problem
[0009] The present disclosure provides a charging apparatus that is
effective for charging a device equipped with a wireless
communication function, while reducing an influence on radio waves
for communications performed by the device to be charged.
Solution to Problem
[0010] A charging apparatus according to an aspect of the present
disclosure is a charging apparatus that transmits electrical power
to a charging target device by electromagnetic induction to charge
a secondary battery of the charging target device, the charging
apparatus including: a position detection section that detects a
position of a power reception coil of the charging target device
placed on the charging apparatus; and an attenuation prevention
section that prevents attenuation of radio waves or a magnetic
field generated around the charging apparatus.
Advantageous Effects of Invention
[0011] The charging apparatus according to the present disclosure
is effective for charging a device to be charged that is equipped
with a wireless communication function, while reducing the
influence on radio waves for communications performed by the device
to be charged.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is an external view that illustrates an example of
how a non-contact charging apparatus and a cellular telephone
according to Embodiment 1 are provided;
[0013] FIG. 2 is a block diagram that illustrates the respective
internal configurations of the non-contact charging apparatus and
the cellular telephone according to Embodiment 1;
[0014] FIG. 3 is a block diagram that illustrates the internal
configuration of a position detection section included in the
non-contact charging apparatus according to Embodiment 1;
[0015] FIG. 4 illustrates an example of the circuit configuration
of a BEF according to Embodiment 1;
[0016] FIG. 5 illustrates another example of the circuit
configuration of the BEF according to Embodiment 1;
[0017] FIG. 6 illustrates a yet another example of the circuit
configuration of the BEF according to Embodiment 1;
[0018] FIG. 7 is a flowchart illustrating operations from detection
of a cellular telephone until conducting non-contact charging that
are performed by the non-contact charging apparatus according to
Embodiment 1;
[0019] FIG. 8 is a block diagram that illustrates the respective
internal configurations of a non-contact charging apparatus and a
cellular telephone according to Embodiment 2;
[0020] FIG. 9 is a block diagram that illustrates the internal
configuration of a position detection section, an NFC control
section, and a switching section that are included in the
non-contact charging apparatus according to Embodiment 2;
[0021] FIG. 10 is a schematic diagram of a magnetic field and a
demagnetizing field that are generated in position detection coils
according to Embodiment 2;
[0022] FIG. 11 is a block diagram that illustrates how BEFs to be
arranged to position detection coils according to Embodiment 2 are
implemented;
[0023] FIG. 12 illustrates a magnetic field generated by a position
detection coil according to Embodiment 2, and an effect that is
caused by inserting a BEF;
[0024] FIG. 13 illustrates a circuit configuration around a
position detection circuit according to Embodiment 2;
[0025] FIG. 14 illustrates waveforms outputted to position
detection coils according to Embodiment 2;
[0026] FIG. 15 is a flowchart that illustrates operations from
detection of a cellular telephone until conducting non-contact
charging and NFC communications that are performed by the
non-contact charging apparatus according to Embodiment 2; and
[0027] FIG. 16 illustrates relative sizes of a position detection
coil and a charging table according to Embodiment 2.
DESCRIPTION OF EMBODIMENTS
[0028] Embodiments will be described in detail hereunder with
reference to the accompanying drawings as appropriate. However, a
more detailed description than is necessary may be omitted. For
example, in some cases a detailed description of well known matters
or a duplicate description regarding a substantially identical
configuration may be omitted. Such omission is to prevent
unnecessary redundancy in the description, and to facilitate
understanding by those skilled in the art.
[0029] Note that the inventors provide the accompanying drawings
and the following description in order for those skilled in the art
to adequately understand the embodiments and do not intend to limit
the subject matter of the invention disclosed in the appended
claims by the accompanying drawings.
Embodiment 1
[0030] First, Embodiment 1 will be described.
[0031] FIG. 1 is an external view illustrating an example of how
non-contact charging apparatus 100 and cellular telephone 150
according to Embodiment 1 are provided. FIG. 1 illustrates a state
in which cellular telephone 150 is placed on charging table 101
that constitutes the upper face of non-contact charging apparatus
100. In this state, non-contact charging apparatus 100 utilizes
non-contact power transmission by means of an electromagnetic
induction effect to perform so-called "non-contact charging" by
supplying electrical power to a secondary battery of cellular
telephone 150 as a device to be charged (hereinafter, referred to
as "charging target device"). That is, non-contact charging is
performed by placing cellular telephone 150 on charging table 101
of non-contact charging apparatus 100 or bringing cellular
telephone 150 near to charging table 101 of non-contact charging
apparatus 100.
[0032] FIG. 2 is a block diagram that illustrates the respective
internal configurations of non-contact charging apparatus 100 and
cellular telephone 150. As shown in FIG. 2, position detection
section 201 having a plurality of coils for detecting a position of
cellular telephone 150 placed on charging table 101 is disposed at
an inner surface of charging table 101. Consequently, charging
table 101 has physical characteristics equivalent to a metal plate
with respect to high-frequency waves. That is, when cellular
telephone 150 as a charging target device is placed on charging
table 101, a high-frequency current that is produced by radio waves
(radio waves generated around cellular telephone 150) used by
cellular telephone 150 to perform wireless communication flows
through the coils of position detection section 201, which causes a
loss of energy of the radio waves. Such a loss causes a reduction
in the strength of the radio waves used by cellular telephone 150
to perform wireless communication.
[0033] In the present embodiment, a reduction in the strength of
radio waves used by cellular telephone 150 that is placed on
charging table 101 of non-contact charging apparatus 100 is
avoided. For this purpose, as shown in FIG. 2, non-contact charging
apparatus 100 includes charging table 101, power supply circuit
204, position detection section 201, non-contact charging circuit
section 210, and coil moving mechanism 207. Further, cellular
telephone 150 is an electronic device that includes a communication
unit capable of wireless communication using a specific frequency
band, and also includes power reception coil 251, secondary battery
257, parallel resonant circuit 258, and charging control circuit
253.
[0034] Each component of non-contact charging apparatus 100 will be
described hereunder. Power supply circuit 204 converts electrical
power supplied to non-contact charging apparatus 100 from an
external power source such as a commercial power source or a
battery mounted in a vehicle into a form that is used by
non-contact charging apparatus 100. Position detection section 201
detects the position of cellular telephone 150 placed on charging
table 101. Note that, the term "position of cellular telephone 150"
refers, more precisely, to the position of power reception coil 251
above the surface on charging table 101.
[0035] Non-contact charging circuit section 210 supplies electrical
power in a non-contact manner to cellular telephone 150.
Non-contact charging circuit section 210 includes charging control
circuit 205, oscillation circuit 206, and power transmission coil
208. Charging control circuit 205 generates a high-frequency
current through oscillation circuit 206 to cause the high-frequency
current to flow through power transmission coil 208. When a
high-frequency current flows through power transmission coil 208 in
the state shown in FIG. 1, an induced electromotive force is
generated in power reception coil 251 of cellular telephone 150.
Note that charging control circuit 205 may also have a charge
detection function that detects a charging state of secondary
battery 257 of cellular telephone 150 and determine when charging
is completed.
[0036] Coil moving mechanism 207 brings power transmission coil 208
close to the position of cellular telephone 150 detected by
position detection section 201, along charging table 101. Coil
moving mechanism 207 includes an X-axis servo motor that moves
power transmission coil 208 in an X-axis direction of the surface
constituted by charging table 101, and a Y-axis servo motor that
moves power transmission coil 208 in a Y-axis direction of the
aforementioned surface.
[0037] FIG. 3 is a block diagram that illustrates the internal
configuration of position detection section 201 included in
non-contact charging apparatus 100. As shown in FIG. 3, position
detection section 201 includes position detection coils 313, BEFs
316, position detection circuit 311, coil moving mechanism control
circuit 312, resonance frequency switching circuit 314, and
resonance frequency variable control circuit 315.
[0038] Position detection coils 313 are a plurality of rows of
coils that are disposed at predetermined intervals on the inner
surface of charging table 101. Position detection coils 313 include
a plurality of X-axis detection coils 313A that detect positions of
power transmission coil 208 of non-contact charging circuit section
210 and power reception coil 251 of cellular telephone 150 in the
X-axis direction, and a plurality of Y-axis detection coils 313B
that detect positions of power transmission coil 208 and power
reception coil 251 in the Y-axis direction. Note that intervals
between the adjacent detection coils for each axis are each smaller
than the external diameter of power reception coil 251. The
position of power reception coil 251 can be accurately detected by
making the aforementioned intervals narrow in this manner.
[0039] BEFs (band-elimination filters) 316 that are each
constituted by an LC parallel resonant circuit are provided between
the coils of position detection coils 313 at intervals of 1/2 a
wavelength or less in terms of electrical length with respect to
the frequency of radio waves used by cellular telephone 150 for
wireless communication. Therefore, at the resonance frequency of
BEFs 316, a band-stop filter function reducing the influence on the
frequency band used by cellular telephone 150 for wireless
communication acts effectively. Each BEF 316 constitutes a circuit
in which the resonance frequency can be varied by control from
resonance frequency variable control circuit 315.
[0040] FIG. 4 illustrates an example of the circuit configuration
of BEF 316. The resonance frequency of BEF 316 depends on the
product of the capacitance value of capacitor 316A and the
inductance value of coil 316B. Accordingly, control of the
resonance frequency of BEF 316 is performed by controlling the
capacitance value and the inductance value.
[0041] FIG. 5 illustrates another example of the circuit
configuration of BEF 316. In the example shown in FIG. 5, a
capacitance element included in BEF 316 is variable capacitance
capacitor 316A'. The capacitance can be controlled by applying a
reverse voltage to variable capacitance capacitor 316A'.
Accordingly, by controlling the voltage applied to variable
capacitance capacitor 316A' of all BEFs 316 of position detection
section 201, resonance frequency variable control circuit 315 can
change the resonance frequency of BEFs 316. Therefore, disposing
only one each of coil 316B' and variable capacitance capacitor
316A' makes it possible to realize BEFs 316 in which the resonance
frequency is variable and which includes a smaller number of
components.
[0042] FIG. 6 illustrates a yet another example of the circuit
configuration of BEF 316. In the example shown in FIG. 6, a
plurality of capacitors 316A'' and coils 316B'' are disposed in
parallel, and the resonance frequency of BEF 316 can be controlled
by resonance frequency variable control circuit 315 controlling on
and off states of switch 317. According to this configuration,
although the number of components increases compared to the
foregoing examples, it is possible to control the resonance
frequency with even higher accuracy because both the capacitance
value and the inductance value can be controlled.
[0043] Position detection circuit 311 excites parallel resonant
circuit 258 of cellular telephone 150 with pulse signals outputted
from position detection coils 313, and receives an echo signal from
power reception coil 251 of cellular telephone 150 to detect the
position of power reception coil 251. The level of the echo signal
from power reception coil 251 fluctuates according to the relative
positions of position detection coils 313 and power reception coil
251. Therefore, position detection circuit 311 can detect the
position of cellular telephone 150 on charging table 101 based on
the relative distance to each position detection coil 313 that
outputs a pulse signal.
[0044] Coil moving mechanism control circuit 312 controls coil
moving mechanism 207 in accordance with the position of power
reception coil 251 detected by position detection circuit 311. That
is, coil moving mechanism control circuit 312 performs control of
the servo motors in the respective axial directions, which
constitute coil moving mechanism 207.
[0045] Resonance frequency switching circuit 314 is configured to
instruct resonance frequency variable control circuit 315 to
determine a resonance frequency so as to perform control relating
to an operation that changes the resonance frequency of BEFs 316 in
response to switching of an input switch that is performed
manually. Note that the purpose of changing the resonance frequency
of BEFs 316 is to reduce the influence on a frequency band used by
cellular telephone 150 for wireless communication, by means of the
resonance frequency of BEFs 316.
[0046] Alternatively, in a case where resonance frequency switching
circuit 314 is equipped with a communication function, an ID of
each frequency band used by cellular telephone 150 may be preset in
cellular telephone 150, and resonance frequency switching circuit
314 may acquire an ID by performing wireless communication with
cellular telephone 150, and may issue instructions to change the
resonance frequency of BEFs 316 to conform to the frequency that
corresponds to this ID.
[0047] In accordance with an instruction from resonance frequency
switching circuit 314, resonance frequency variable control circuit
315 changes either or both of the capacitance value and the
inductance value of BEFs 316 to control the resonance frequency of
BEFs 316.
[0048] The above described charging control circuit 205, coil
moving mechanism control circuit 312, and resonance frequency
variable control circuit 315 are implemented by such as a
microcomputer that executes a computer program in which operation
processing is described. That is, using a CPU, a ROM, and a RAM of
the microcomputer, the CPU executes a computer program that is
stored in the ROM, while using the RAM as a working space. In
non-contact charging apparatus 100, charging control circuit 205,
coil moving mechanism control circuit 312, and resonance frequency
control circuit 315 may be implemented by means of the same
microcomputer.
[0049] Hereunder, operations from detection of cellular telephone
150 until conducting non-contact charging that are performed by
non-contact charging apparatus 100 of the present embodiment will
be described referring to FIG. 7. As shown in FIG. 7, when
electrical power supply to non-contact charging apparatus 100 from
an external power source starts, power supply circuit 204 performs
electrical power conversion for non-contact charging apparatus 100,
and non-contact charging apparatus 100 is activated (step S40).
Alternatively, after power is supplied from an external power
source, non-contact charging apparatus 100 may be activated by
means of a manual switch or the like provided in non-contact
charging apparatus 100.
[0050] Next, position detection section 201 determines whether or
not cellular telephone 150 is present on charging table 101, and if
cellular telephone 150 is present on charging table 101, position
detection section 201 detects the position thereof (step S41).
Detection of the position of cellular telephone 150 is performed by
position detection circuit 311 exciting parallel resonant circuit
258 of cellular telephone 150 with pulse signals outputted from
position detection coils 313, and receiving an echo signal from
power reception coil 251. If the position of cellular telephone 150
can be detected in step S41, the process advances to step S42. Note
that, the term "position of cellular telephone 150" refers more
precisely to the position of power reception coil 251 above the
surface of charging table 101. In contrast, if the position of
cellular telephone 150 cannot be detected in step S41, the process
advances to step S48. In step S48, non-contact charging apparatus
100 transitions to a standby state.
[0051] In step S42, resonance frequency switching circuit 314
determines the resonance frequency of BEFs 316 in conformity with
the frequency band of radio waves used by cellular telephone 150
for wireless communication. Next, resonance frequency variable
control circuit 315 controls either or both of the capacitance
value and the inductance value of BEFs 316 so that the resonance
frequency of BEFs 316 becomes the frequency determined in step S42
(step S43).
[0052] Next, coil moving mechanism control circuit 312 controls
coil moving mechanism 207 based on the position of cellular
telephone 150 detected in step S41 to bring power transmission coil
208 close to the position of power reception coil 251 of cellular
telephone 150 (step S44). Subsequently, non-contact charging
circuit section 210 causes a high-frequency current to flow through
power transmission coil 208 to generate an induced electromotive
force in power reception coil 251 by an electromagnetic induction
action between power transmission coil 208 and power reception coil
251, thereby starting charging of secondary battery 257 of cellular
telephone 150 (step S45).
[0053] Next, position detection section 201 determines whether or
not cellular telephone 150 is present on charging table 101, and if
cellular telephone 150 is present on charging table 101, detects
the position of cellular telephone 150 (step S46). If the position
of cellular telephone 150 can be detected in step S46, the process
advances to step S47 and continues non-contact charging. In
contrast, if the position of cellular telephone 150 cannot be
detected in step S46, the process advances to step S48 where
non-contact charging apparatus 100 transitions to a standby
state.
[0054] As described above, non-contact charging apparatus 100 of
the present embodiment causes the resonance frequency of BEFs 316
disposed on the inner surface of charging table 101 to conform to
the frequency of radio waves used by cellular telephone 150 for
wireless communication. For this reason, a band-stop filter for the
aforementioned frequency is configured in BEFs 316. As a result,
cellular telephone 150 is charged while a reduction in the strength
of radio waves at the aforementioned frequency is limited.
[0055] Forming a band-stop filter for a frequency band used by
cellular telephone 150 for wireless communication in position
detection coils 313 prevents a high-frequency current produced by
radio waves of the frequency band used by cellular telephone 150
from flowing through position detection coils 313. Consequently, a
loss of energy of the radio waves used by cellular telephone 150
can be avoided.
[0056] Thus, according to the charging apparatus of the present
embodiment, since BEFs are used as an attenuation prevention
section that prevents attenuation of radio waves of a specific
frequency that are generated around the charging apparatus itself,
such as in the vicinity of the charging table, non-contact charging
can be performed while avoiding a reduction in the strength of
radio waves used by the charging target device.
Embodiment 2
[0057] Next, Embodiment 2 will be described. Note that components
that are the same as in Embodiment 1 are denoted by the same
reference symbols, and a detailed description of such components is
omitted.
[0058] In the state shown in FIG. 1, in a case where cellular
telephone 150 includes a near field communication (NFC) function,
non-contact charging apparatus 100 performs near field
communication (hereunder, referred to as "NFC communication") that
is a kind of wireless communication that utilizes an
electromagnetic induction effect.
[0059] Various kinds of information communication can be performed
by NFC communication between cellular telephone 150 and an external
device connected to non-contact charging apparatus 100.
[0060] Various types of contents are conceivable as the contents of
such communication. For example, when a car navigation apparatus is
connected as an external device to non-contact charging apparatus
100, the destination of the car navigation can be set by
transmitting destination information set in cellular telephone 150
to the car navigation apparatus by NFC communication.
[0061] However, since the contents of communication by NFC
communication between cellular telephone 150 and an external device
depart from the purpose of the present embodiment, a detailed
description of the communication contents is omitted herein.
[0062] A carrier wave of 13.56 MHz is used for NFC communication,
and transmission and reception of data is performed by utilizing a
magnetic field that is generated in an antenna coil. Consequently,
an antenna coil that generates a magnetic field of a frequency of
13.56 MHz is required in the charging table or in the vicinity of
the charging table in order to perform communication by NFC.
[0063] The charging apparatus of the present embodiment is provided
with an NFC function by allocating one coil among the large number
of position detection coils disposed inside the charging table for
dual use as an antenna coil to be used for NFC.
[0064] Accordingly, since a position detection coil is used in a
dual manner as an antenna coil, an NFC function can be provided in
a charging table of the related art without newly adding an antenna
for NFC in the charging table.
[0065] Therefore, while the charging apparatus of the present
embodiment may of course be put to good use indoors such as in an
ordinary household or office where it is easy to secure a location
for disposing objects and appliances, the charging apparatus of the
present embodiment can be advantageously provided in an automobile
or transport aircraft in which space is limited.
[0066] FIG. 8 is a block diagram that illustrates the internal
configurations of non-contact charging apparatus 100 and cellular
telephone 150, respectively.
[0067] As shown in FIG. 8, non-contact charging apparatus 100
includes a charging table on a surface side of non-contact charging
apparatus 100 on which cellular telephone 150 is placed.
[0068] Position detection section 201 that includes a plurality of
coils for detecting the position of cellular telephone 150 that is
placed on charging table 101, and NFC control section 202 for
conducting NFC communication with cellular telephone 150 are
disposed on the inner surface side of charging table 101 (inner
side of the apparatus).
[0069] In addition, in order to use one coil among the plurality of
coils of position detection section 201 as a position detection
coil and an NFC coil, switching section 203 is provided for
switching the coil according to each function.
[0070] In addition, non-contact charging apparatus 100 also
includes power supply circuit 204, charging control circuit 205,
oscillation circuit 206, coil moving mechanism 207, power
transmission coil 208, and external device connection section
209.
[0071] External device connection section 209 connects non-contact
charging apparatus 100 and the aforementioned external device that
is to be connected to non-contact charging apparatus 100. That is,
the external device performs bi-directional communication with
position detection section 201 and NFC control section 202 through
external device connection section 209.
[0072] Further, cellular telephone 150 is an electronic device that
has a communication unit capable of wireless communication using a
specific frequency, and includes power reception coil 251, power
reception resonant circuit 252, charging control circuit 253, NFC
antenna coil 254 as a near field communication antenna, NFC
resonant circuit 255, NFC control circuit 256, and secondary
battery 257.
[0073] Hereunder, each component of non-contact charging apparatus
100 will be described.
[0074] FIG. 9 is a block diagram that illustrates the internal
configurations of position detection section 201 and NFC control
section 202 as a near field communication control section that are
included in non-contact charging apparatus 100.
[0075] As shown in FIG. 9, position detection section 201 includes
position detection coils 301, position detection control circuit
302, and switches 303 that are controlled by switching section 203,
and NFC control section 202 includes NFC control circuit 304 and
switches 305 that are controlled by switching section 203.
[0076] Further, position detection section 201 and NFC control
section 202 include position detection coils 301, position
detection control circuit 302, coil moving mechanism 207, NFC
control circuit 304, switching section 203, and switches 303 and
switches 305 that are controlled by switching section 203.
[0077] Position detection coils 301 are a plurality of rows of
coils that are disposed at predetermined intervals on the inner
surface of charging table 101.
[0078] The position detection coils 301 include a plurality of
X-axis direction position detection coils 301A that detect the
position in the X-axis direction of power transmission coil 208 and
power reception coil 251 of cellular telephone 150, and a plurality
of Y-axis direction position detection coils 301B that detect the
position in the Y-axis direction of power transmission coil 208 and
power reception coil 251.
[0079] Note that intervals between the adjacent detection coils for
each axis are each smaller than the external diameter of the power
reception coil. The position of power reception coil 251 can be
accurately detected by making the aforementioned intervals narrow
in this manner.
[0080] In this case, according to the present embodiment, one coil
among the plurality of position detection coils 301 to be disposed
is caused to have dual functions by also utilizing the coil as an
NFC antenna coil (coil denoted by 301' in FIG. 9).
[0081] As shown in FIG. 9, the plurality of position detection
coils 301 to be disposed in charging table 101 are disposed in both
the X-axis direction and Y-axis direction of charging table 101,
and the position detection coils in the axial directions intersect
with each other.
[0082] Accordingly, there are also a plurality of position
detection coils (301A in FIG. 9) that are orthogonal to position
detection coil 301' that also serves as an NFC antenna coil
(hereunder, referred to as "NFC dual-purpose position detection
coil").
[0083] In general, for NFC, the antenna coil of a transmission side
generates a magnetic field of 13.56 MHz. When a magnetic flux of
the magnetic field passes through the antenna coil on the reception
side, an induced electromotive force is generated in the antenna
coil on the reception side and communication is performed utilizing
this electrical power.
[0084] Accordingly, a magnetic field strength that is sufficient to
generate an electrical power that is necessary in order to activate
an IC mounted on the reception side is required for the magnetic
field that is generated in a coil on the transmission side.
[0085] In addition, an induced electromotive force that is
generated in the antenna coil on the reception side is proportional
to the strength of the magnetic field that passes through the
antenna coil on the reception side.
[0086] Since a plurality of X-axis direction position detection
coils 301A intersect with NFC dual-purpose position detection coil
301', magnetic flux of 13.56 MHz that is generated by NFC
dual-purpose position detection coil 301' also passes through the
intersecting plurality of X-axis direction position detection coils
301A.
[0087] Therefore, as shown in FIG. 10, the plurality of X-axis
direction position detection coils 301A that intersect with NFC
dual-purpose position detection coil 301' receive magnetic field
(magnetic field generated around its own apparatus) 401 generated
by NFC dual-purpose position detection coil 301', and generate a
magnetic field around the coils by means of an electromagnetic
induction effect. The direction of this magnetic field is the
opposite direction to that of the magnetic field generated by NFC
dual-purpose position detection coil 301' (hereunder, referred to
as "demagnetizing field 402").
[0088] Magnetic field 401 that originally is necessary for NFC
communication is attenuated by demagnetizing field 402. Because of
the attenuation of magnetic field 401, the induced electromotive
force that is generated in NFC antenna coil 254 on the reception
side also decreases.
[0089] When the electromotive force generated in the circuit on the
reception side decreases, the communication becomes unstable and
communication errors arise in the communication with NFC control
circuit 256 of cellular telephone 150, and communication cannot be
performed in some cases.
[0090] Therefore, according to the non-contact charging apparatus
of the present embodiment, in order to prevent attenuation of
magnetic field 401 that is required for NFC communication, as shown
in FIG. 11, as an attenuation prevention section, BEFs
(band-elimination filters) 501 constituted by an LC parallel
resonant circuit are connected in series to the plurality of X-axis
direction position detection coils 301A that intersect with NFC
dual-purpose position detection coil 301'.
[0091] In the example illustrated in FIG. 11, although BEFs 501 are
disposed at places at which NFC dual-purpose position detection
coil 301' and X-axis direction position detection coils 301A
intersect with each other, the places at which BEFs 501 are
disposed are not necessarily limited to these positions, and as
long as BEFs 501 are connected in series at optional places on
coils 301 other than NFC dual-purpose position detection coil 301',
any configuration can be employed.
[0092] The BEFs are LC parallel resonant circuits that attenuate
only a predetermined frequency on the circuit. Therefore, the
predetermined frequency attenuated by the BEFs is set to the same
frequency as the carrier wave of 13.56 MHz that is used for
NFC.
[0093] As a result, as shown in FIG. 12, it is possible to avoid
generation of a high-frequency current even when the magnetic field
of 13.56 MHz generated by the NFC antenna coil passes through
X-axis direction position detection coils 301A to which BEFs 501
are serially connected, and also to avoid generation of a
demagnetizing field.
[0094] According to the present embodiment, for convenience, an
example has been described in which, with respect to NFC
dual-purpose position detection coil 301' that is a Y-axis
direction position detection coil, BEFs are connected in series
only to the plurality of X-axis direction position detection coils
301A intersecting with NFC dual-purpose position detection coil
301'.
[0095] However, BEFs may alternatively be inserted to Y-axis
direction position detection coils 301B that are disposed close to
or overlapping with NFC dual-purpose position detection coil
301'.
[0096] More specifically, although in the examples shown in FIG. 9
and FIG. 11, a configuration is exemplified in which a plurality of
coils that are parallel to each other are aligned without
overlapping, arranging these coils so as to overlap (so that the
regions enclosed by the coils overlap) can improve the accuracy of
detecting the position of power reception coil 251 of cellular
telephone 150.
[0097] In this case (case in which coils overlap), inserting BEFs
to an optional coil (overlapping coil) of Y-axis direction position
detection coils 301B excluding NFC dual-purpose position detection
coil 301' makes it possible to avoid generation of a demagnetizing
field by the optional coil (overlapping coil).
[0098] At this time, the larger the area of a coil of coils 301A or
301B that overlaps with NFC dual-purpose position detection coil
301' is, the greater the effect of the generation of demagnetizing
field when the BEFs are inserted. Accordingly, it is preferable to
select a coil to which to insert BEFs in accordance with the
arrangement of position detection coils 301 (taking into
consideration the degree of overlapping with the dual-purpose
coil).
[0099] In addition, although FIG. 11 illustrates an example in
which a plurality of BEFs are disposed on a single coil, the
purpose of inserting the BEFs is to inhibit (attenuate) the flow of
a current of 13.56 MHz that is used for NFC on coils other than NFC
dual-purpose position detection coil 301'. Thus, as long as this
purpose can be satisfied, there is no necessity to limit the number
of BEFs that are disposed on a coil.
[0100] Hereunder, an implementation state when a position detection
coil is actually caused to serve a dual purpose as an NFC antenna
coil will be described.
[0101] According to the non-contact charging apparatus of the
present embodiment, the configuration shown in FIG. 13 is adopted
so that NFC dual-purpose position detection coil 301' handles a
frequency for position detection of power reception coil 251 and a
frequency for NFC communication as different frequencies.
[0102] As shown in FIG. 13, the function of NFC dual-purpose
position detection coil 301' can be switched by controlling
switches 303 and 305 that are connected to switching section
203.
[0103] NFC dual-purpose position detection coil 301' has a function
as a position detection coil when switching section 203 turns on
switch 303 and turns off switch 305 (this state is referred to as
"state 1").
[0104] When NFC dual-purpose position detection coil 301' functions
as a position detection coil, NFC dual-purpose position detection
coil 301' functions as one of a plurality of position detection
coils that excite power reception resonant circuit 252 of cellular
telephone 150 with pulse signals outputted from position detection
control circuit 302 and receive a magnetic field (hereunder,
referred to as "echo signal") that is re-emitted from power
reception coil 251 to thereby detect the position of power
reception coil 251 of cellular telephone 150.
[0105] In this case, the level of the echo signal from power
reception coil 251 fluctuates according to the relative positions
of position detection coils 301 and power reception coil 251.
[0106] Therefore, position detection control circuit 302 can detect
the position of cellular telephone 150 on charging table 101 based
on the level of the echo signal that differs according to the
relative distance between each position detection coil 301 that
outputs pulse signals and power reception coil 251.
[0107] Accordingly, when NFC dual-purpose position detection coil
301' is caused to function as a position detection coil, NFC
dual-purpose position detection coil 301' serves as a path that
transmits a pulse signal that causes power reception resonant
circuit 252 of cellular telephone 150 to resonate, and transmits an
echo signal that is outputted from the power reception coil to
position detection control circuit 302.
[0108] Next, when switching section 203 turns off switch 303 and
turns on switch 305, NFC dual-purpose position detection coil 301'
has a function as an NFC antenna coil (this state is referred to as
"state 2").
[0109] NFC control circuit 304 includes NFC control IC 701 that
controls and outputs a carrier wave of 13.56 MHz when performing
desired communication by NFC, and matching circuit 702 that
performs impedance matching with respect to a path between NFC
control IC 701 and NFC dual-purpose position detection coil
301'.
[0110] NFC uses a carrier wave of 13.56 MHz for communication.
Accordingly, impedance matching is performed in matching circuit
702, and the impedance of matching circuit 702 is previously
adjusted so as to resonate at the frequency of the carrier wave
that is outputted from NFC control IC 701.
[0111] In the present embodiment, passive components such as a
capacitor and a coil implemented in matching circuit 702 are used
for impedance matching.
[0112] NFC control circuit 304 and NFC control circuit 256 that is
mounted in cellular telephone 150 perform NFC communication through
respective antenna coils thereof.
[0113] NFC control IC 701 and NFC control circuit 256 that is
mounted in cellular telephone 150 perform communication through
respective antenna coils thereof, and perform desired operations in
accordance with the communication result. Switching section 203
controls switches 303 and 305 to switch between state 1 and state
2.
[0114] FIG. 14 illustrates the relationship between the time axis
and signals outputted to NFC dual-purpose position detection coil
301' when switches 303 and 305 are controlled to switch between
state 1 and state 2.
[0115] In segment 1 in FIG. 14, NFC dual-purpose position detection
coil 301' enters state 1 and a pulse wave for detecting the
position of power reception coil 251 installed in cellular
telephone 150 is outputted to position detection coils 301.
[0116] A signal that is outputted to NFC dual-purpose position
detection coil 301' is shown in FIG. 14. A pulse waveform for
position detection that is shown by a dashed line in segment 1 is
illustrated by, for convenience, showing a pulse waveform that is
outputted to X-axis direction position detection coils 301A and
Y-axis direction position detection coils 301B in a similar manner
to the position detection coils shown in FIG. 9.
[0117] During the period of segment 1, in order to detect the
position coordinates of power reception coil 251 that is installed
in non-contact charging apparatus 100, pulse signals are output to
each position detection coil included in X-axis direction position
detection coils 301A and Y-axis direction position detection coils
301B by performing switching control of the switches of position
detection control circuit 302.
[0118] Note that although the example shown in FIG. 14 exemplifies
a method that outputs pulse signals in sequence to X-axis direction
position detection coils 301A and Y-axis direction position
detection coils 301B, the present embodiment is not necessarily
limited to this method.
[0119] For example, a method can be considered that, with respect
to segment 1, first outputs a pulse signal to X-axis direction
position detection coils 301A, and only when power reception coil
251 is detected, then outputs a pulse signal to Y-axis direction
position detection coils 301B.
[0120] That is, a method may also be adopted that outputs a pulse
signal to X-axis direction position detection coils 301A, and ends
segment 1 unless an echo signal is detected. In this case, the time
period required for segment 1 can be shortened when power reception
coil 251 is not placed on the charging table.
[0121] In a case where position coordinates of power reception coil
251 are detected after a pulse signal is outputted to position
detection coils 301, or in a case where no echo signal is detected
and position detection control circuit 302 is thus determined that
power reception coil 251 is not placed on non-contact charging
apparatus 100, switching section 203 turns switch 303 off and turns
switch 305 on to thereby transition to segment 2 (state 2).
[0122] Next, segment 2 shown in FIG. 14 shows a state at a time
that the NFC dual-purpose antenna coil transitions to state 2.
[0123] In segment 2, NFC communication is performed between NFC
control circuit 304 and NFC control circuit 256 mounted in cellular
telephone 150 using a carrier wave of 13.56 MHz.
[0124] In segment 2, NFC control IC 701 performs polling for a
predetermined period to detect a device that is a target of NFC
communication. NFC control circuit 256 mounted in cellular
telephone 150 transmits a response command to NFC control IC 701 by
using load modulation of a carrier wave of 13.56 MHz that is sent
to NFC control circuit 256.
[0125] Accordingly, in segment 2, if this response command is not
detected, NFC control IC 701 determines that no NFC function is
provided in cellular telephone 150.
[0126] When NFC control IC 701 determines that no NFC function is
provided in cellular telephone 150, or at a time point that the NFC
communication with NFC control circuit 256 mounted in cellular
telephone 150 ends the operation, a transition is made to segment 1
again from segment 2.
[0127] Hereunder, operations from detection of cellular telephone
150 until conducting non-contact charging and conducting NFC
communication that are performed by non-contact charging apparatus
100 of the present embodiment will be described referring to FIG.
15.
[0128] When the supply of electrical power to non-contact charging
apparatus 100 from an external power source such as a commercial
power source starts, power supply circuit 204 converts the
electrical power into a form that is used by non-contact charging
apparatus 100, and thus non-contact charging apparatus 100 is
activated (step S10).
[0129] However, after power is supplied from an external power
source, non-contact charging apparatus 100 may alternatively be
activated by means of a manual switch or the like provided in
non-contact charging apparatus 100.
[0130] After activation of non-contact charging apparatus 100,
switching section 203 performs control of switches 303 and 305 to
cause NFC dual-purpose position detection coil 301' to transition
to state 1 (step S11). In the present embodiment, this state is
referred to as "initial state."
[0131] After transition to state 1, in step S12, position detection
section 201 determines whether or not cellular telephone 150 is
present on charging table 101 during segment 1.
[0132] In step S12, if cellular telephone 150 is present on
charging table 101, the position of cellular telephone 150 is
detected.
[0133] Detection of the position of cellular telephone 150 is
performed by position detection section 201 exciting power
reception resonant circuit 252 of cellular telephone 150 with pulse
signals that are outputted from position detection coils 301 and
receiving an echo signal from power reception coil 251.
[0134] Note that the term "position of cellular telephone 150"
refers more precisely to the position of power reception coil 251
on the surface of charging table 101.
[0135] If position detection control circuit 302 determines that
power reception coil 251 is placed on charging table as a result of
receiving an echo signal (YES in step S12), the position
coordinates of power reception coil 251 are stored in a memory
provided in the position detection control circuit (step S13).
[0136] If no power reception coil is detected in step S12, or after
the process in step S13 ends, switching section 203 controls switch
303 and switch 305 so that NFC dual-purpose position detection coil
301' transitions to state 2 (step S14).
[0137] After NFC dual-purpose position detection coil 301'
transitions to state 2 in step S14, in segment 2, NFC communication
is performed between NFC control circuit 304 and NFC control
circuit 256 that is mounted in cellular telephone 150.
[0138] In segment 2, NFC control IC 701 performs polling for a
predetermined period to detect a device that is a target of NFC
communication and thereby determines whether or not cellular
telephone 150 placed on non-contact charging apparatus 100 is
equipped with an NFC function (step S15).
[0139] NFC control circuit 256 mounted in cellular telephone 150
transmits a response command to NFC control IC 701 by using load
modulation of a carrier wave of 13.56 MHz that is sent to NFC
control circuit 256. Accordingly, in segment 2, if this response
command is not detected, NFC control IC 701 determines that no NFC
function is provided in cellular telephone 150 (NO in step
S15).
[0140] If NFC control IC 701 determines in step S15 that an NFC
function is provided in cellular telephone 150, NFC communication
is started (step S16).
[0141] After NFC communication is started in step 16, processing to
determine whether or not NFC communication ends is continued
successively (step S17).
[0142] If NFC control IC 701 determines that no NFC function is
provided in cellular telephone 150 (NO in step S15), or at a time
point that NFC communication with NFC control circuit 256 mounted
in cellular telephone 150 ends (YES in step S17), NFC dual-purpose
position detection coil 301' transitions to segment 1 again from
segment 2 (step S18).
[0143] When NFC dual-purpose position detection coil 301'
transitions to state 1 again, the flow changes according to whether
or not position detection control circuit 302 has detected power
reception coil 251 in step S12, that is, whether or not position
coordinates of power reception coil 251 are stored in the memory
provided in position detection control circuit 302 (step S19).
[0144] In step S19, if power reception coil 251 is detected in step
S12, the process advances to step S21 in which position detection
control circuit 302 controls coil moving mechanism 207 to bring
power transmission coil 208 close to the position of power
reception coil 251.
[0145] If it is determined in step S19 that position coordinates
are not stored (NO in step 19), the process returns to the initial
state. Accordingly, unless power reception coil 251 is detected,
NFC dual-purpose position detection coil 301' repeats the flow
between step S12 and step S19.
[0146] In step S22, whether or not movement of power transmission
coil 208 has ended is determined. If movement has not ended (NO in
step S22), the process returns to step S21 to continue movement of
power transmission coil 208.
[0147] After movement of power transmission coil 208 to the
position of power reception coil 251 ends through execution of step
S21 and step S22 (YES in step S22), charging control circuit 205
generates a high-frequency current through oscillation circuit 206
and causes the high-frequency current to flow through power
transmission coil 208.
[0148] When the high-frequency current flows through power
transmission coil 208 in the state shown in FIG. 1, an induced
electromotive force is generated in power reception coil 251 of
cellular telephone 150, and charging starts (step S23).
[0149] In addition, it is determined whether or not a request to
conduct NFC communication with cellular telephone 150 has sent to
non-contact charging apparatus 100 from an external device that is
connected to external device connection section 209 during charging
(step S24).
[0150] If a request to conduct NFC communication is sent from an
external device during charging of cellular telephone 150 (YES in
step S24), switching section 203 controls switch 303 and switch 305
so that NFC dual-purpose position detection coil 301' transitions
to state 2 (step S25).
[0151] Operations to be performed in step S26 to step S29 as the
flow after transition to state 2 are the same as the operations in
step S15 to step S18 that are described above.
[0152] Note that a configuration may also be adopted that, while
performing the processing in step S26 to step S29, performs
processing that stops the charging operation of power transmission
coil 208, or performs control that increases the distance of power
transmission coil 208 from NFC dual-purpose position detection coil
301', or performs both the processing to stop charging and the
movement control with respect to power transmission coil 208.
[0153] Adopting such a configuration makes it possible to reduce
the influence that a magnetic field generated by power transmission
coil 208 has on a magnetic field that is used for NFC
communication.
[0154] However, in this case, it is necessary to perform processing
that moves power transmission coil 208 to the position of power
reception coil 251 during a period from the end of NFC
communication to before step S30.
[0155] Further, a configuration may be adopted in which, if
position detection control circuit 302 does not detect a device
that is a target for NFC communication in step S26, information to
the effect that a target device is not detected is transmitted from
position detection control circuit 302 to the external device via
external device connection section 209.
[0156] After the flow from step S26 to step S29, the charging
operation is continued (step S30). Thus, it is possible to conduct
NFC communication even during charging of cellular telephone
150.
[0157] Finally, in step S31, if power reception coil 251 is no
longer present on power transmission coil 208 during the charging
operation, charging control circuit 205 stops the charging
operation. Accordingly, charging control circuit 205 repeatedly
executes the processing from step S24 to step S31 while performing
the charging operation.
[0158] When charging control circuit 205 stops the charging
operation in step S31, the processing returns to the initial state
and an operation to detect power reception coil 251 is
executed.
[0159] By means of the above flow, a charging operation and NFC
communication with respect to cellular telephone 150 that is placed
on non-contact charging apparatus 100 are performed.
[0160] By means of the present flow, it is possible to perform a
charging operation also with respect to "a cellular telephone
provided with a non-contact charging function, but not provided
with an NFC function."
[0161] Further, it is possible to conduct NFC communication by
repeating the operations from step S12 to step S19 also with
respect to "a cellular telephone provided with an NFC function, but
not provided with a charging function."
[0162] By means of the above operations, it is possible for
non-contact charging apparatus 100 to execute a desired operation
depending on a function provided in a cellular telephone that is
placed on the charging table.
[0163] Further, the processing flow that is illustrated herein is
only an example of implementation of the present embodiment. Thus,
it is also possible to adopt a configuration in which a user uses a
manual switch or the like mounted in the charging apparatus to
switch between state 1 and state 2, depending on a function
provided in the cellular telephone that is placed on the charging
table.
[0164] Next, the size of the charging table of the present
embodiment is described using FIG. 16. FIG. 16 illustrates the
relative sizes of cellular telephone 150 and charging table 101. In
consideration of the fact that the charging table of the present
embodiment is mainly used for charging cellular telephones, it is
necessary to design the size of the charging table on the
assumption that the charging table will be used to charge cellular
telephones in various sizes.
[0165] Cellular telephones typically have a shape that fits in a
geometric frame such as a square or rectangular shape. Therefore,
when charging table 101 is formed in a rectangular shape, the
relative size of charging table 101 with respect to cellular
telephone 150 is important.
[0166] The strength of a magnetic field depends on the size of the
antenna that generates the magnetic field. Therefore, NFC antenna
coil 254 that is mounted in cellular telephone 150 is disposed so
as to be as large a size as possible inside the casing of cellular
telephone 150.
[0167] In the example shown in FIG. 16, a situation is assumed in
which NFC antenna coil 254 of cellular telephone 150 is disposed so
as to overlap with the center of cellular telephone 150.
[0168] NFC communication is performed by utilizing an induced
electromotive force produced by a magnetic field that is generated
by one antenna passing through another antenna.
[0169] Accordingly, the larger that a region at which antennas that
perform communication overlap with each other is, the greater the
degree to which the strength of the magnetic field increases and
the sensitivity rises.
[0170] As shown in FIG. 16, length Lc in a short-side direction of
charging table 101 is made larger than length Lm in a short-side
direction of cellular telephone 150, and length Lc in the
short-side direction of charging table 101 is made smaller than the
sum of length Lm in the short-side direction of cellular telephone
and interval D1 of NFC dual-purpose position detection coil
301'.
[0171] However, charging table 101 and NFC dual-purpose position
detection coil 301' are disposed so as to be in parallel with each
other in their long-side direction.
[0172] Further, "interval D1" of NFC dual-purpose position
detection coil 301' can be described in another way as "the width
in the short-side direction (short-side direction of charging
table) of a magnetic field excited by NFC dual-purpose position
detection coil 301'," in the example shown in FIG. 16. "Interval
D1" is the distance between one straight line in the longitudinal
direction of NFC dual-purpose position detection coil 301' and
another straight line that faces the one straight line.
[0173] For practical purposes, it is preferable for interval D1 of
the NFC dual-purpose position detection coil to be considered
according to what width (or length) in the short-side direction of
cellular telephone 150 is occupied by a magnetic field that is
excited by NFC dual-purpose position detection coil 301'.
[0174] Setting the size of the charging table in this manner makes
NFC antenna coil 254 of cellular telephone 150 always overlap with
half or more of NFC dual-purpose position detection coil 301'.
[0175] Accordingly, by defining the size of the charging table
relative to the size of the cellular telephone as described above,
and defining a position detection coil that is disposed at the
center of the plurality of Y-axis direction position detection
coils 301B that are disposed in the short-side direction of the
charging table as NFC dual-purpose position detection coil 301', no
matter which position of the charging table a cellular telephone is
placed at, antennas that perform NFC communication overlap with
each other and allow communication to be performed.
[0176] That is, both a charging function and an NFC function can be
realized in a compatible manner irrespective of the position of the
cellular telephone. As described above, according to the present
embodiment, BEFs (band elimination filters) are serially connected
in a plurality of position detection coils that intersect with a
position detection coil that is caused to function as an NFC
antenna coil, and a frequency that is attenuated using the BEFs is
made the same frequency as a carrier wave of 13.56 MHz that is used
for NFC.
[0177] Therefore, even if a magnetic field of 13.56 MHz generated
by the NFC antenna coil passes through a position detection coil in
which BEFs are disposed, a high-frequency current of 13.56 MHz to
be generated on the position detection coils is avoided.
[0178] Accordingly, it is also possible to avoid a demagnetizing
field to be generated from position detection coils by an
electromagnetic induction effect by means of a high-frequency
current.
[0179] That is, according to the charging apparatus of the present
embodiment, it is possible to avoid the generation of a
demagnetizing field that is to be generated around position
detection coils that intersect with a position detection coil that
is caused to function as an antenna coil for NFC communication, and
also possible to realize both a charging function and NFC
communication in a compatible manner.
[0180] Note that a carrier wave that is used for near field
communication (NFC communication) is not limited to 13.56 MHz, and
the charging apparatus of the present embodiment can be adapted to
an antenna of a device that performs communication utilizing
electromagnetic induction.
[0181] As described in the above, the charging apparatus of the
present embodiment is effective for charging a charging target
device that has a wireless communication function, while reducing
the influence on radio waves used by the charging target
device.
[0182] Note that, with respect the foregoing description, the
contents described in Embodiments 1 and 2 may be optionally
combined. According to this variation, the effect of optionally
combining Embodiments 1 and 2 can be obtained.
[0183] The disclosures of the specifications, the drawings, and the
abstracts included in Japanese Patent Application No. 2012-044027
filed on Feb. 29, 2012 and Japanese Patent Application No.
2012-195860 filed on Sep. 6, 2012 are incorporated herein by
reference in their entirety.
INDUSTRIAL APPLICABILITY
[0184] The charging apparatus of the present disclosure is useful
as a non-contact charging apparatus of a charging target device
that has a wireless communication function or the like.
Specifically, the charging apparatus of the present disclosure is
useful as a non-contact charging apparatus that charges a cellular
telephone or a smartphone or the like.
REFERENCE SIGNS LIST
[0185] 100 Non-contact charging apparatus [0186] 101 Charging table
[0187] 150 Cellular telephone (example of a charging target device)
[0188] 201 Position detection section [0189] 202 NFC control
section [0190] 203 Switching section [0191] 204 Power supply
circuit [0192] 205 Charging control circuit [0193] 206 Oscillation
circuit [0194] 207 Coil moving mechanism [0195] 208 Power
transmission coil [0196] 209 External device connection section
[0197] 210 Non-contact charging circuit section [0198] 251 Power
reception coil [0199] 252 Power reception resonant circuit [0200]
253 Charging control circuit [0201] 254 NFC antenna coil [0202] 255
NFC resonant circuit [0203] 256 NFC control circuit [0204] 257
Secondary battery [0205] 258 Parallel resonant circuit [0206] 301
Position detection coil [0207] 301A X-axis direction position
detection coil [0208] 301B Y-axis direction position detection coil
[0209] 301' NFC dual-purpose position detection coil [0210] 302
Position detection control circuit [0211] 303 Switch [0212] 304 NFC
control circuit [0213] 305 Switch [0214] 311 Position detection
circuit [0215] 312 Coil moving mechanism control circuit [0216] 313
Position detection coils [0217] 313A X-axis detection coils [0218]
313B Y-axis detection coils [0219] 314 Resonance frequency
switching circuit [0220] 315 Resonance frequency variable control
circuit [0221] 316 BEF [0222] 316A, 316A'' Capacitor [0223] 316A'
Variable capacitance capacitor [0224] 316B, 316B', 316B'' Coil
[0225] 317 Switch [0226] 401 Magnetic field [0227] 402
Demagnetizing field [0228] 501 BEF [0229] 701 NFC control IC [0230]
702 Matching circuit [0231] Lc Length in short-side direction of
charging table [0232] Lm Length in short-side direction of cellular
telephone [0233] D1 Interval of NFC dual-purpose position detection
coil
* * * * *