U.S. patent application number 17/102903 was filed with the patent office on 2021-04-15 for electric shielding structures.
This patent application is currently assigned to Apple Inc.. The applicant listed for this patent is Apple Inc.. Invention is credited to Cheung-Wei Lam, Vaneet Pathak, Andro Radchenko, Rahul A. Sabnani, Martin Schauer.
Application Number | 20210110969 17/102903 |
Document ID | / |
Family ID | 1000005266019 |
Filed Date | 2021-04-15 |
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United States Patent
Application |
20210110969 |
Kind Code |
A1 |
Radchenko; Andro ; et
al. |
April 15, 2021 |
ELECTRIC SHIELDING STRUCTURES
Abstract
Wireless power transmitting devices according to embodiments of
the present technology may include a contact surface configured to
support one or more wireless power receiving devices. The wireless
power transmitting devices may include a plurality of coils. The
wireless power transmitting devices may also include a shield
positioned between the plurality of coils and the contact surface.
The shield may include one or more shield members, each shield
member axially aligned with a separate coil of the plurality of
coils, and may include a multilayer structure exhibiting various
conductivities.
Inventors: |
Radchenko; Andro; (San Jose,
CA) ; Pathak; Vaneet; (Los Altos, CA) ;
Schauer; Martin; (Fremont, CA) ; Lam; Cheung-Wei;
(San Jose, CA) ; Sabnani; Rahul A.; (Colma,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Assignee: |
Apple Inc.
Cupertino
CA
|
Family ID: |
1000005266019 |
Appl. No.: |
17/102903 |
Filed: |
November 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16145503 |
Sep 28, 2018 |
10855118 |
|
|
17102903 |
|
|
|
|
62688547 |
Jun 22, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 50/402 20200101;
H01F 27/36 20130101; H01F 38/14 20130101; H02J 50/70 20160201; H02J
50/10 20160201 |
International
Class: |
H01F 27/36 20060101
H01F027/36; H01F 38/14 20060101 H01F038/14; H02J 50/10 20060101
H02J050/10; H02J 50/40 20060101 H02J050/40; H02J 50/70 20060101
H02J050/70 |
Claims
1. A wireless power transmitting device, comprising: a contact
surface configured to support one or more wireless power receiving
devices; one or more coils; and a shield positioned between the one
or more coils and the contact surface, wherein the shield comprises
one or more shield members, each shield member axially aligned with
a separate coil of the one or more coils.
2. The wireless power transmitting device of claim 1, wherein the
shield comprises a conductive chassis extending about a perimeter
of the shield.
3. The wireless power transmitting device of claim 2, wherein the
shield comprises a conductive sheet spanning an internal area
defined by the conductive chassis.
4. The wireless power transmitting device of claim 3, wherein the
conductive sheet comprises a first material, wherein the one or
more shield members comprise a second material, and wherein the
conductive sheet is characterized by a higher sheet resistance than
the shield members.
5. The wireless power transmitting device of claim 2, wherein the
shield comprises a conductive drain extending from at least one
shield member of the one or more shield members to the conductive
chassis.
6. The wireless power transmitting device of claim 5, wherein the
shield comprises a plurality of shield members, and wherein each
shield member is electrically coupled with another shield member
with a bridge or is electrically coupled with the conductive
chassis with a conductive drain.
7. The wireless power transmitting device of claim 5, wherein the
conductive drain is characterized by an arcuate shape, wherein the
conductive drain is positioned between the at least one shield
member and the conductive chassis, and wherein the conductive drain
is shaped and positioned to limit overlap with an underlying coil
relative to a straight-member conductive drain.
8. The wireless power transmitting device of claim 1, wherein each
coil of the one or more is characterized by a substantially annular
shape, and wherein each shield member of the one or more shield
members comprises a body characterized by a substantially annular
shape.
9. The wireless power transmitting device of claim 8, wherein each
shield member of the one or more shield members defines a gap
extending from an inner annular edge of the body to an outer
annular edge of the body, and wherein the gap forms a discontinuity
about a circumference of each shield member.
10. The wireless power transmitting device of claim 9, wherein each
shield member further defines a plurality of slots extending from
the inner annular edge of the body towards the outer annular edge
of the body.
11. The wireless power transmitting device of claim 8, wherein each
shield member of the one or more shield members comprises a
grounding pin extending from an inner annular edge of the body and
electrically coupling the shield member with a ground of the
wireless power transmitting device.
12. A wireless power transmitting device, comprising: a contact
surface configured to support one or more wireless power receiving
devices; an induction coil; and a shield positioned between the
induction coil and the contact surface, wherein the shield
comprises a shield member overlying and aligned with the induction
coil.
13. The wireless power transmitting device of claim 12, wherein the
shield comprises a conductive chassis extending about a perimeter
of the shield, and wherein the shield comprises a conductive sheet
spanning an internal area defined by the conductive chassis.
14. The wireless power transmitting device of claim 13, wherein the
conductive sheet comprises silver, and wherein the shield member
comprises copper.
15. The wireless power transmitting device of claim 13, wherein the
shield comprises a plurality of shield members, and wherein each
shield member is electrically coupled with another shield member
with a bridge or is electrically coupled with the conductive
chassis with a conductive drain.
16. A wireless power transmitting device, comprising: a contact
surface configured to support one or more wireless power receiving
devices; one or more coils; and a shield positioned between the one
or more coils and the contact surface, wherein the shield
comprises: a conductive chassis, a conductive sheet extending
across an internal area defined by the conductive chassis, and a
shield member positioned on the conductive sheet and overlying a
coil of the one or more coils.
17. The wireless power transmitting device of claim 16, wherein the
conductive sheet comprises a first material, wherein the shield
member comprises a second material, and wherein the conductive
sheet is characterized by a higher sheet resistance than the shield
member.
18. The wireless power transmitting device of claim 16, wherein the
shield comprises a plurality of shield members, and wherein each
shield member is electrically coupled with another shield member
with a bridge or is electrically coupled with the conductive
chassis with a conductive drain.
19. The wireless power transmitting device of claim 18, wherein
each coil of the one or more coils is characterized by a
substantially annular shape, and wherein each shield member of the
plurality of shield members comprises a body characterized by a
substantially annular shape.
20. The wireless power transmitting device of claim 19, wherein
each shield member of the plurality of shield members defines a gap
extending from an inner annular edge of the body to an outer
annular edge of the body, and wherein the gap forms a discontinuity
about a circumference of each shield member body.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/145,503, filed Sep. 28, 2018, which claims
the benefit of U.S. Provisional Application No. 62/688,547, filed
Jun. 22, 2018, entitled "ELECTRIC SHIELDING STRUCTURES", each of
which are hereby incorporated by reference in their entirety for
all purposes.
TECHNICAL FIELD
[0002] The present technology relates to wireless charging systems.
More specifically, the present technology relates to shielding
structures for wireless charging systems.
BACKGROUND
[0003] Wireless charging systems allow power transmission to
devices without requiring a power cord or other connective wire
coupled to the device to be powered or recharged. Wireless charging
systems, as well as the devices being charged, may produce noise
and emissions that can reduce charging efficiency, and may be
subject to regulatory compliance.
SUMMARY
[0004] Wireless power transmitting devices according to embodiments
of the present technology may include a contact surface configured
to support one or more wireless power receiving devices. The
wireless power transmitting devices may include a plurality of
coils. The wireless power transmitting devices may also include a
shield positioned between the plurality of coils and the contact
surface. The shield may include one or more shield members, each
shield member axially aligned with a separate coil of the plurality
of coils.
[0005] In some embodiments, the shield may include a conductive
chassis extending about a perimeter of the shield. The shield may
include a conductive sheet spanning an internal area defined by the
conductive chassis. The conductive sheet may include a first
material, and the one or more shield members may include a second
material. The conductive sheet may be characterized by a higher
sheet resistance than the shield members. The shield may include a
conductive drain extending from at least one shield member of the
one or more shield members to the conductive chassis. The shield
may include a plurality of shield members, and each shield member
may be electrically coupled with another shield member with a
bridge or may be electrically coupled with the conductive chassis
with a conductive drain.
[0006] In some embodiments, the conductive drain may be
characterized by an arcuate shape. The conductive drain may be
positioned between the at least one shield member and the
conductive chassis, and the conductive drain may be shaped and
positioned to limit overlap with an underlying coil relative to a
straight-member conductive drain. Each coil of the plurality of
coils may be characterized by a substantially annular shape, and
each shield member of the one or more shield members may include a
body characterized by a substantially annular shape. Each shield
member of the one or more shield members may define a gap extending
from an inner annular edge of the body to an outer annular edge of
the body, and the gap may form a discontinuity about a
circumference of each shield member. Each shield member may further
define a plurality of slots extending from the inner annular edge
of the body towards the outer annular edge of the body. Each shield
member of the one or more shield members may include a grounding
pin extending from an inner annular edge of the body and
electrically coupling the shield member with a ground of the
wireless power transmitting device.
[0007] Some embodiments of the present technology may also
encompass a wireless power transmitting device. The device may
include a contact surface configured to support one or more
wireless power receiving devices. The device may include a first
layer of coils distributed in a first planar arrangement. The
device may include a second layer of coils vertically offset from
the first layer of coils and positioned between the contact surface
and the first layer of coils. The second layer of coils may be
distributed in a second planar arrangement whereby coils of the
second layer of coils are laterally offset from coils of the first
planar arrangement. The device may also include a shield positioned
between the second layer of coils and the contact surface. The
shield may include a shield member overlying and aligned with a
coil of the second layer of coils.
[0008] In some embodiments, the shield may include a conductive
chassis extending about a perimeter of the shield. The shield may
include a conductive sheet spanning an internal area defined by the
conductive chassis. The conductive sheet may include silver, and
the shield member may include copper. The shield may include a
plurality of shield members, and each shield member may be
electrically coupled with another shield member with a bridge or
may be electrically coupled with the conductive chassis with a
conductive drain.
[0009] Some embodiments of the present technology may also
encompass a wireless power transmitting device. The device may
include a contact surface configured to support one or more
wireless power receiving devices. The device may include a
plurality of coils. The device may also include a shield positioned
between the plurality of coils and the contact surface. The shield
may include a conductive chassis, a conductive sheet extending
across an internal area defined by the conductive chassis, and a
shield member positioned on the conductive sheet and overlying a
coil of the plurality of coils.
[0010] In some embodiments, the conductive sheet may include a
first material, and the shield member may include a second
material. The conductive sheet may be characterized by a higher
sheet resistance than the shield member. The shield may include a
plurality of shield members, and each shield member may be
electrically coupled with another shield member with a bridge or
may be electrically coupled with the conductive chassis with a
conductive drain. Each coil of the plurality of coils may be
characterized by a substantially annular shape, and each shield
member of the plurality of shield members may include a body
characterized by a substantially annular shape. Each shield member
of the plurality of shield members may define a gap extending from
an inner annular edge of the body to an outer annular edge of the
body, and the gap may form a discontinuity about a circumference of
each shield member body.
[0011] Such technology may provide numerous benefits over
conventional technology. For example, the present systems may
reduce device emissions and electrical noise. Additionally, the
systems may reduce eddy currents on shield components and limit an
impact on charging efficiency. These and other embodiments, along
with many of their advantages and features, are described in more
detail in conjunction with the below description and attached
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A further understanding of the nature and advantages of the
disclosed embodiments may be realized by reference to the remaining
portions of the specification and the drawings.
[0013] FIG. 1 shows a schematic diagram of a wireless charging
system according to some embodiments of the present technology.
[0014] FIG. 2 shows a schematic plan view of a wireless power
transmitting device according to some embodiments of the present
technology.
[0015] FIG. 3A shows a schematic perspective view of a wireless
power transmitting device according to some embodiments of the
present technology.
[0016] FIG. 3B shows a partial schematic perspective view of a
wireless power transmitting device according to some embodiments of
the present technology.
[0017] FIG. 4 shows a schematic plan view of an exemplary shield
for a wireless power transmitting device according to some
embodiments of the present technology.
[0018] FIGS. 5A-5G show schematic plan views of exemplary shields
for a wireless power transmitting device according to some
embodiments of the present technology.
[0019] FIG. 6A shows a chart of emissions effects at a first coil
position for exemplary shields according to some embodiments of the
present technology.
[0020] FIG. 6B shows a chart of emissions effects at a second coil
position for exemplary shields according to some embodiments of the
present technology.
[0021] Several of the figures are included as schematics. It is to
be understood that the figures are for illustrative purposes, and
are not to be considered of scale unless specifically stated to be
of scale. Additionally, as schematics, the figures are provided to
aid comprehension and may not include all aspects or information
compared to realistic representations, and may include exaggerated
material for illustrative purposes.
[0022] In the figures, similar components and/or features may have
the same numerical reference label. Further, various components of
the same type may be distinguished by following the reference label
by a letter that distinguishes among the similar components and/or
features. If only the first numerical reference label is used in
the specification, the description is applicable to any one of the
similar components and/or features having the same first numerical
reference label irrespective of the letter suffix.
DETAILED DESCRIPTION
[0023] A wireless power system may include a wireless power
transmitting device that allows power to be transmitted wirelessly
to a wireless power receiving device. The wireless power
transmitting device may be a device having a number of forms
including a wireless charging mat, a wireless charging puck, a
wireless charging stand, a wireless charging table, or other
wireless power transmitting equipment. The wireless power
transmitting device may include one or more coils, such as
induction coils or wound coils, that are used in transmitting
wireless power to one or more wireless power receiving coils in
wireless power receiving devices. The wireless power receiving
devices may be any number of rechargeable devices that incorporate
an induction coil or coils configured to receive power from the
transmitting coil or coils. Any device may be configured to receive
wireless power, including portable devices including cellular
telephones, electronic watches, wearable devices including fitness
devices, media players, computers including laptop computers and
tablet computers, battery-powered earphones, remote controls, or
any other electronic device or other wireless power receiving
equipment.
[0024] During operation, the wireless power transmitting device may
supply alternating current signals to one or more wireless power
transmitting coils. In response, the transmission coils may
transmit alternating-current electromagnetic signals, or wireless
power signals, to one or more corresponding coils in the wireless
power receiving device. Rectifier circuitry in the wireless power
receiving device may convert the received wireless power signals
into direct-current (DC) power for powering the wireless power
receiving device, or recharging a battery, for example.
[0025] An illustrative wireless power system or wireless charging
system is shown in FIG. 1. As illustrated, wireless power system 8
may include wireless power transmitting device 12, and one or more
wireless power receiving devices, such as wireless power receiving
device 10. Device 12 may be a stand-alone device such as a wireless
charging mat, may be built into furniture, or may be other wireless
charging equipment. Device 10 may be any portable electronic device
including any of the components previously described. During
operation of system 8, a user may place one or more devices 10 on a
contact surface of device 12, which may constitute a charging
surface. Power transmitting device 12 may be coupled with a source
of alternating-current voltage such as alternating-current power
source 50, such as a wall outlet that supplies line power or other
source of mains electricity or a portable power source, which may
include an additional device such as a laptop computer, for
example. Power transmitting device 12 may also or alternatively
include a battery, such as battery 38, for supplying power. A power
converter, such as AC-DC power converter 40, can convert power from
a mains power source or other AC power source into DC power that
may be used to power control circuitry 42 and other circuitry in
device 12. During operation, control circuitry 42 may use wireless
power transmitting circuitry 34 and one or more coils 36, which may
be electrically coupled with circuitry 34, to transmit
alternating-current electromagnetic signals 48 to device 10, and
which may provide wireless power to wireless power receiving
circuitry 46 of device 10.
[0026] Power transmitting circuitry 34 may include switching
circuitry, such as transistors in an inverter circuit, which may be
engaged or disengaged based on control signals provided by control
circuitry 42 to create AC current signals through appropriate coils
36. As the AC currents pass through a coil 36 that is being driven
by the inverter circuit, alternating-current electromagnetic
fields, which may constitute wireless power signals 48, may be
produced. The fields may be received by one or more corresponding
coils 14 coupled with wireless power receiving circuitry 46 in
receiving device 10. When the alternating-current electromagnetic
fields are received by coil 14, corresponding AC currents and
voltages may be induced in coil 14. Rectifier circuitry in
circuitry 46 may convert received AC signals associated with
wireless power signals from one or more coils 14 into DC voltage
signals for powering device 10. The DC voltages may be used in
directly powering components in device 10 such as display 52,
buttons, components, or other sensors 54, wireless communications
circuitry 56, or other input-output devices 22 and/or control
circuitry 20. The converted voltages may also be used to charge an
internal battery in device 10, such as battery 18.
[0027] Devices 12 and 10 include control circuitry 42 and 20, which
may include storage and processing circuitry such as
microprocessors, microcontrollers, and/or application-specific
integrated circuits with processing circuits. Control circuitry 42
and 20 may be configured to execute instructions for implementing
desired control and communications features in system 8. For
example, control circuitry 42 and/or 20 may be used in determining
power transmission levels, processing sensor data, processing user
input, processing other information such as information on wireless
coupling efficiency from transmitting circuitry 34, processing
information from receiving circuitry 46, using information from
circuitry 34 and/or 46, such as signal measurements on output
circuitry in circuitry 34 and other information from circuitry 34
and/or 46, to determine when to start and stop wireless charging
operations. The circuitry may be used in adjusting charging
parameters such as charging frequencies, determining coil
assignments in a multi-coil array, measuring wireless power
transmission levels, and performing other control functions.
[0028] In an exemplary system, wireless transmitting device 12 may
be a wireless charging mat or other wireless power transmitting
equipment that may include an array of coils 36 configured to
supply wireless power over a wireless charging surface. An
illustrative arrangement is shown in FIG. 2, where device 12
includes an array of coils 36 that may be used in wireless charging
operations as previously explained. Wireless transmitting device 12
may include an overlying contact surface 60 configured to detect
when a wireless power receiving device is placed on the contact
surface. For example, sensors or other devices may detect the
presence of a device having wireless power receiving
capabilities.
[0029] Coils 36 are illustrated in an exemplary pattern in which
multiple layers of coils are distributed in a stacked arrangement
within device 12. In other embodiments similarly encompassed by the
present technology more or fewer coils may be included in the
wireless transmitting device 12 including 1 coil or 2 or more
coils, including greater than or about 5 coils, greater than or
about 10 coils, greater than or about 15 coils, greater than or
about 20 coils, greater than or about 50 coils, greater than or
about 100 coils, greater than or about 1,000 coils, or more
depending on the size, shape, and patterning of the coils 36, as
well as the size and shape of wireless power transmitting device
12. For example, in some embodiments, device 12 may be the size of
a placemat or smaller, while in other embodiments device 12 may be
a conference table having dimensions of several meters. Coils 36
may be distributed in any pattern and may be arranged in any number
of configurations including any number of layers. In embodiments
encompassed by the present technology the coils may be all of a
similar size and shape as illustrated, although in other
embodiments coils of different sizes and shapes may be used
together within a device. In some embodiments, coils 36 may be
arranged in a single row, two rows, three rows, five rows, or more,
depending on the distribution of coils. For example, coils 36 may
be arranged in each row so as not to completely overlap a coil in
any other row. As illustrated, although coils 36 overlap underlying
coils, there is a lateral offset between the coils in each row, as
well as in all rows. This offset may both increase an area for
charging coverage across the contact surface 60, as well as limit
or reduce detrimental or interference effects on proximate coils.
Coils 36 may not be exposed in some embodiments, and may be
enclosed or covered by a planar dielectric structure such as a
plastic member, or other material or structure, forming contact
surface 60.
[0030] During operation, a user may place one or more devices 10 on
contact surface 60, which may be configured to support one or more
wireless power receiving devices. Foreign objects such as coins,
paper clips, scraps of metal foil, and/or other foreign conductive
objects may be accidentally placed on surface 60. System 8 may be
configured to automatically detect whether conductive objects
located on surface 60 correspond to devices 10 or incompatible
foreign objects, and may respond in each case appropriately, such
as by engaging coils proximate to devices 10, while disengaging or
not engaging coils proximate incompatible foreign objects. For
example, external objects 62 and 64 may overlap one or more coils
36. In some embodiments, objects 62 and 64 may each be portable
electronic devices 10, and system 8 may engage one or more coils
proximate or underlying the devices. In other situations, either
object 62 or 64 may be an incompatible object, and system 8 may not
engage, or may actively disengage coils proximate or underlying the
devices. In some embodiments, before system 8 allows wireless power
to be transmitted to some objects, system 8 may check whether
objects located on surface 60 include sensitive components such as
radio-frequency identification (RFID) devices or other potentially
sensitive electronic equipment that could be damaged upon exposure
to fields from coils 36. System 8 may engage coils at reduced power
in such situations, or may not engage coils proximate sensitive
devices.
[0031] Wireless charging systems may generally operate on magnetic
fields. However, the components of both the wireless power
transmission device and the wireless power receiving device may
include other electrical components and conductive components,
which may produce or enhance radiative emissions and conductive
emissions that interfere with charging and other operations.
Electric noise generated by components or by specific
characteristics of the transmitting or receiving devices may be
capacitively coupled to the adjacent device, which may result in
further enhancement of the emissions. An electric field shield, or
e-shield or shield as will be described throughout the disclosure,
may be positioned between the coils of the transmitting and
receiving devices. In the simplest sense, a conductive sheet may be
positioned across the surface of the transmitter to block noise or
unwanted emissions, but such a sheet would simultaneously block the
charging process. To avoid drastic reductions in charging
efficiency, a solid e-shield may be limited to lower conductivity
components and/or minimal thicknesses. However, these concessions
may adversely limit the operation on emissions. Slots or cuts may
be formed in a solid shield, but in multiple-coil arrangements
introducing slots may increase unwanted eddy currents that act back
upon the magnetic field and further affect charging efficiency.
Accordingly, electric field shields for multiple-coil charging
systems face many competing challenges.
[0032] The present technology may include a shield, or e-shield,
utilizing one or more components configured to reduce electric
field strengths on coils characterized by higher emissions, while
limiting an impact on magnetic fields. Returning to FIG. 2, an
exemplary wireless power transmitting device 12 may include
multiple layers of coils, or simply multiple closely spaced coils.
Each coil of the multiple coils or plurality of coils may produce
different electric fields based on a number of factors. For
example, coils nearer to an edge of the device may be subject to a
more asymmetrical ground plane, while coils nearer to a center of
the device may have a more symmetrical ground plane. Exemplary
devices may include a ferrite layer beneath the coils, which may
also affect coils in a non-uniform manner depending on the
thickness and shape of the ferrite. Additionally, each coil may be
characterized by a different rotation of the coil, as well as
different termination configurations in whether the terminations
are co-located or positioned on separate sides of the coil.
Wireless power transmitting device 12 may also include a cable 65,
which may couple with power source 50 described previously, and may
couple with device 12 at connector 67. Each coil may be distributed
at a distance from connector 67, which may further impact
electrical characteristics. For example, while one coil may be
proximate connector 67, another coil may be twice the distance to
connector 67, which may impact the emissions at certain
frequencies. Consequently, many characteristics of the device 12
and associated components may impact the electrical emissions.
[0033] In some embodiments having layers of coils, coils adjacent
the contact surface may have increased emissions over coils beneath
the top layer. For example, FIG. 2 illustrates a configuration
including three layers of coils, although fewer or more layers may
be included. A first layer of coils 35 may be seated closest to a
ferrite or other material layer, when included, and may be furthest
from contact surface 60. First layer of coils 35 is illustrated as
having six coils in a first arrangement across a first plane,
although more or less coils as well as any other lateral
distribution across the first plane is similarly encompassed, such
as seven coils, eight coils, or more. A second layer of coils 37
may be included on a second plane vertically offset from, such as
above, the first plane. The second coils may be distributed in a
second arrangement, which may be similar to or different from the
arrangement of the first layer of coils. As illustrated, the second
layer of coils includes seven coils across a second plane, although
more or less coils as well as any other lateral distribution across
the second plane is similarly encompassed. The coils of the second
layer of coils may be laterally offset from coils in the
arrangement of the first layer of coils. Hence, in some embodiments
no coils or few coils of the second layer of coils may fully
overlap any coil of the first layer of coils.
[0034] The illustrated embodiment also includes a third layer of
coils 39 overlying the second layer of coils 37. The third layer of
coils may be closest to the contact surface 60. The third layer of
coils may be included on a third plane vertically offset from, such
as above the second plane and/or first plane. The third coils may
be distributed in a third arrangement, which may be similar to or
different from the arrangement of the first or second layers of
coils. As illustrated, the third layer of coils includes seven
coils across a third plane in a similar arrangement as the second
layer of coils, although more or less coils as well as any other
lateral distribution across the third plane is similarly
encompassed. The third layer of coils may be laterally offset from
coils in the first and second layers, and in some embodiments no
coils or few coils of the third layer of coils may fully overlap
any coil of the first layer and/or second layer of coils. As seen
in the example illustrated, upper coils, such as those in the
second and third layers of coils, may act as a partial shield to
underlying coils, which may reduce the emissions of the underlying
coils. However, the uppermost coils in the third layer of coils,
without an additional shield, may not be affected by underlying
components, and may generate higher emissions than coils in the
second layer and first layer.
[0035] In some embodiments of the present technology, a shield may
be included that may selectively target coils predetermined to
contribute higher levels of emissions, or may contribute emissions
at particular frequencies to be controlled. Whether from a lateral
position within the device configuration, or from additional
characteristics such as a position in an uppermost layer, for
example, individual coils may be selectively targeted with
e-shields according to the embodiments of the present
technology.
[0036] FIG. 3A shows a schematic perspective view of a wireless
power transmitting device 300 according to some embodiments of the
present technology. Wireless power transmitting device 300 may
include any of the components of wireless power charging device 12
described above, and may include any of the components and
arrangements previously described. Device 300 may include a housing
305 incorporating a number of components for providing wireless
power to one or more receiving devices. In some embodiments housing
305 may be or include a shell or casing in which the components may
be contained, and may be of any number of form factors. For
example, housing 305 may be a mat, plate, puck, or other similarly
sized component, although in other embodiments housing 305 may be a
table, countertop, nightstand, desk, or any surface within which
additional components for providing wireless power may be
contained.
[0037] Housing 305 may be made of any number of materials including
plastics, woods, metals, stones, or any material that may be
formed, carved, or hollowed to allow placement of additional
components. Housing 305 may include a contact surface 307, which
may be a dielectric material or any other material that may be
configured to support one or more wireless power receiving devices.
For example, in some embodiments a contact surface 307 extending
across a top area of the housing may be a conductive material,
although in some embodiments the choice of conductive material may
be configured to limit blocking of or interference with magnetic or
other radiated waves through the contact surface, which may provide
wireless charging capabilities.
[0038] Within housing 305 may be a number of components including
circuitry, which may include a circuit board, sensors for detecting
objects on or proximate contact surface 307 and for measuring or
controlling the provision of wireless power from device 300, as
well as any other materials as previously described. Housing 305
may include material 315, which may be ferrite in one example, or
any other material that may be used to block, direct, or otherwise
contribute to control of generated wireless power fields. Above
material 315 may be one or more coils 310, such as a plurality of
coils, which may be or include characteristics of coils 36
described above, and may be used to contribute to the generation of
wireless power, which may be transmitted to a receiving device
positioned on contact surface 307. Coils 310 may include any number
of coils that may be distributed and arranged in any pattern across
an internal volume of device 300. The coils may be included in a
single layer, or may be included in multiple layers, including
greater than or about 2 layers, greater than or about 3 layers,
greater than or about 4 layers, greater than or about 5 layers,
greater than or about 10 layers, or more. Device 300 may also
include a connector 320, which may allow a power source to be
coupled with wireless power transmitting device 300, and may
operate as an electrical ground path from the device.
[0039] Wireless power transmitting device 300 may also include a
shield 325 positioned between coils 310 and contact surface 307.
Shield 325 may include one or more shield members 330 that may be
distributed across coils 310. Shield members 330 may be stand-alone
components as illustrated, and thus shield 325 may include multiple
separate components, although as will be described further below in
additional embodiments shield 325 may include a one-piece design of
the components or shield members. Shield members 330 may be
positioned to affect electric noise from one or more of the coils
310. As previously explained, based on a number of factors, certain
coils may contribute to electric noise generation more than other
coils. Operational testing of a particular device 300 form factor
may identify one or more coils contributing higher emissions. For
example, in configurations including multiple layers of coils, a
top layer of coils may be contributing higher emissions than lower
layers of coils. Shield members 330 may be positioned in a
configuration related to the coils contributing to increased
radiative or conductive emissions.
[0040] As shown in the figure, shield members 330 may be positioned
over one or more coils, and may be positioned to substantially
overlap individual coils. In one embodiment shown in FIG. 3A,
shield members 330 are arranged in a layer to distribute one shield
member 330 over each coil 310 in a top layer of coils, such as all
seven coils as described in top layer of coils 39 of FIG. 2. It is
to be understood that when more or fewer coils are included, more
or fewer shield members may be included as well. Additionally,
shield members 330 may not be positioned over every coil within a
particular coil layer. Because shield members 330 may impact
charging efficiency, the number of shield members may be selected
to beneficially reduce electrical noise, while minimizing an impact
on charging. Shield members 330 may be axially aligned with
individual coils 310, and may be sized to be of a smaller diameter,
substantially similar diameter, or greater diameter than a coil 310
over which the shield member 330 is positioned.
[0041] Turning to FIG. 3B is shown a partial schematic perspective
view of wireless power transmitting device 300 according to some
embodiments of the present technology. FIG. 3B may show an enhanced
view of shield 325 and shield members 330. The coils of wireless
power transmitting device 300 may include wound coils that may each
be characterized by a substantially annular shape, which may allow
one or more wire connections within a central area defined by the
annulus. Although the shields may be characterized by any shape,
including an elliptical or other geometric pattern, in some
embodiments shield members 330 may also be characterized by a
substantially annular shape. Such a shape may correspond to the
annular shape of the coil over which the shield member is being
positioned, while limiting effects on additional coils, which may
be present in lower layers of coils. For example, when a solid
shield member is utilized, the shield member may overlap the
intended coil, and may also cover more than only the overlapping
portion of underlying coils, and may also cover underlying coil
portions positioned under a central area defined by an overlying
coil. When covered by a shield, the shield may further limit
wireless charging field transmission for the underlying coil or
coils, which may further reduce charging efficiency of the wireless
power transmitting device. Accordingly, in some embodiments shield
members 330 may be characterized by an annular shape to limit
impact on underlying coils separate from the coil with which the
shield member is associated.
[0042] Shield members 330 may define a gap 335 formed radially
across or in some configuration through each shield member 330, as
will be described in further detail below. Gap 335 may fully extend
from an inner annular edge of the shield member 330 to an outer
annular edge of the shield member, which may form a discontinuity
about a circumference of each shield member. In embodiments where
shield member 330 may be characterized by a non-circular or
elliptical geometry, a gap may be formed as a discontinuity about a
perimeter of the shield member, which may also be termed a
circumference. Shield members 330 may be a conductive material in
some embodiments to allow blocking of electrical noise. However,
such a conductor proximate a source coil may allow eddy currents to
be induced on the shield members 330 from developed magnetic fields
from the underlying coils. If the shield member forms a complete
circular shape, or forming a complete loop, the developed eddy
currents may increasingly react back on the coil opposing the
magnetic field and further reducing charging efficiency of the
device. Accordingly, gap 335 may reduce or limit eddy current
generation as well as the accompanying heat generation from the
eddy currents.
[0043] Shield members 330 may include a grounding pin 340, or
grounding member allowing dissipation of generated electrical
currents on the shield members 330. Grounding pin 340 may extend
from either the inner annular edge or the outer annular edge of the
shield members 330. As illustrated, in some embodiments the
grounding pin 340 extends from an inner annular edge of the shield
member. Grounding pin 340 may electrically couple the shield member
with an electrical ground of the wireless power transmitting device
300. For example, shield members 330 may be at an uppermost layer
within the housing of the wireless power transmitting device, and
may be located just below a contact surface of the housing. A
ground within the housing may be located at a lower plane within
the housing, including on an underlying circuit board, and may be
located below all coil layers, below a ferrite or other material
layer, or elsewhere. Grounding pin 340 may be adapted to extend
from an inner annular edge of each shield member and extend
laterally to or towards a central region defined by the shield
member. The grounding pin 340 may then transition vertically and
extend down or otherwise vertically within the housing to
electrically connect or couple with an electrical ground within the
device. In other embodiments, the grounding pin 340 may extend
laterally to an edge or other location to couple with the housing,
which may provide a ground path. Additionally, in some embodiments,
grounding pins 340 may extend to one or more other shield members
to electrically couple the shields, which may then include one or
more ground paths from one or more other shield members to the
housing laterally, vertically, or otherwise, which may be similar
to any of the additional embodiments described elsewhere.
[0044] Shield members 330 may be or include a conductive material,
which may facilitate a reduction in electrical noise. The shield
members may include any number of materials or combinations of
materials, which may be or include silver, copper, aluminum, zinc,
nickel, stainless steel, or any other material which may be used to
reduce the electrical noise transmitted or formed within the
wireless power transmitting device.
[0045] Additional shield designs are also encompassed in the
present technology, which may further control radiative and
conductive emissions from or to the wireless power transmitting
device. As explained previously, coils in lower layers of coils may
also produce emissions, although these emissions may be less than
those in upper layers of coils, or coils in a similar plane, which
may be characterized by higher emissions due to other factors
described above. These emissions may be reduced or controlled in
some embodiments by utilizing a compound or multi-layer e-shield
that may address coils generating lower levels of emissions due to
their lateral location or position in a lower layer of coils. The
multi-layer or multi-material e-shields may further control noise
associated with wireless charging operations.
[0046] FIG. 4 shows a schematic plan view of an exemplary shield
400 for a wireless power transmitting device according to some
embodiments of the present technology. Shield 400 may be a
multi-layer or multi-material shield providing additional reduction
in electrical noise by providing a low-level reduction to all coils
included within a device, as well as providing a targeted reduction
in individual coils contributing increased emissions. Shield 400
may be utilized with any of the wireless power transmitting devices
previously described, and may be positioned within a device housing
as an internal component. The shield 400 may be positioned
proximate a contact surface of the wireless power receiving device,
and may be positioned between a contact surface and a plurality of
coils used for wireless power charging. Any device with which
shield 400 may be used may include any number, configuration, or
arrangement of coils, including coils of different sizes, shapes,
orientations, and layers.
[0047] Shield 400 may include a number of shield members 410
disposed within the shield 400. Shield members 410 may include any
of the patterns, materials, or characteristics as shield members
330 described previously. Shield members 410 may be positioned with
the shield 400 such that when shield 400 is incorporated within a
wireless power transmitting device, shield members 410 are axially
aligned or otherwise associated with or overlie particular coils of
the device. Shield 400 is illustrated with seven shield members 410
distributed in a similar orientation as described previously
relative to the seven coils of the top layer of coils 39 included
in that exemplary device. However, it is to be understood that
shield 400 may include any number of shield members which may be
used or positioned within the shield to selectively overlie
particular coils determined to generate electrical noise in any
configuration of coils. The remaining portions of the disclosure
will similarly be based on the coil configuration illustrated in
FIG. 2, although it is to be understood that any number of
additional or alternative configurations as described previously
may similarly benefit from incorporation of a shield 400, or
variation thereof as discussed elsewhere.
[0048] Shield 400 may include a chassis 415 that may be made of any
material, and may include a conductive material. For example,
chassis 415 may be or include any of the previously identified
materials, or any other conductive material, which may allow
electrical current to be distributed about the chassis. In some
embodiments, chassis 415 may be the same material as shield members
410. Chassis 415 may be characterized by any number of designs, and
may extend about a perimeter of the shield. Chassis 415 may be
sized according to the size of the corresponding wireless power
transmitting device in which shield 400 may be incorporated.
Chassis 415 may be sized to couple or connect with a housing of the
device, which may be any of the housing materials previously
described. Chassis 415 may define a coupling location 417, which
may allow transfer of electrical current to an electrical ground of
the device, including through a cable coupled with the device as
previously described. Coupling location 417 may be a pattern or
profile allowing overlap of conductive chassis 415 with a
conductive aspect of an associated housing, which may allow
transfer of current from the shield 400.
[0049] The profile of chassis 415 may form an elliptical,
polygonal, or other geometric structure, which may form a loop of
conductive material. To limit eddy currents induced on the
conductive chassis 415, the chassis may define a number of contact
tips 416 distributed about the chassis. As illustrated, contact
tips 416 are formed from an outer edge of the chassis towards an
inner edge, such as an inner annular edge, which may form a
continuous edge about the structure. In other embodiments, the
chassis may be characterized by the reverse profile in which an
outer edge of the chassis forms a continuous edge, while contact
tips 416 are formed from the inner edge towards the outer edge. Any
number of contact tips may be formed about the chassis, and the
number may depend on the size of the shield and/or the extent of
impact on charging operations. For example, a shield characterized
by a diameter of 50 cm or less, may define up to or at least 50
contact tips, while a shield characterized by a diameter of 5
meters, less, or more, may define less than 300 contact tips. In
other embodiments a shield characterized by a diameter of 5 meters
may define at least 1,000 contact tips in other configurations. Any
number of contact tips may be formed, which may facilitate a
reduction in eddy current effects on the charging capabilities of
the wireless power transmitting device.
[0050] Shield 400 may also include a sheet 420 spanning an internal
area defined by the chassis 415. Sheet 420 may further facilitate a
reduction in electrical noise. Shield members 410 may be formed
over or under the sheet 420, and in some embodiments sheet 420 may
be formed about shield members 410 so that sheet 420 and shield
members 410 are coplanar along a plane defined by sheet 420. Sheet
420 may be or include any of the conductive materials previously
described. The conductivity of sheet 420 may be tuned to limit an
impact on the charging capabilities of the associated wireless
power transmitting device. For example, by increasing a thickness
of sheet 420 or selecting a more conductive material, sheet 420 may
further reduce emissions. However, as thickness and/or conductivity
increases across sheet 420, device charging capability may be
reduced, and may be limited. Accordingly, in some embodiments sheet
420 may be sized and selected to be characterized by a lower
conductivity than shield members 410 positioned across sheet
420.
[0051] For example, sheet 420 may include a thin-film conductive
material, which may be characterized by a thickness of less than or
about 1 .mu.m, and may be characterized by a thickness of less than
or about 500 nm, less than or about 250 nm, less than or about 100
nm, less than or about 90 nm, less than or about 80 nm, less than
or about 70 nm, less than or about 60 nm, less than or about 50 nm,
less than or about 40 nm, less than or about 30 nm, less than or
about 20 nm, less than or about 10 nm, or less, as well as within
any lesser range encompassed by these stated ranges. By forming
sheet 420 at a reduced thickness, sheet 420 may be or include a
more conductive material. For example, in some embodiments shield
members may be or include copper, while sheet 420 may be or include
silver. Although silver may be more conductive than copper, the
thickness of sheet 420 may be such that sheet 420 is characterized
by a sheet resistance higher than the shield members 410. Shield
members 410 may be characterized by a thickness between or about
100 nm and about 100 .mu.m, such as greater than or about 1 .mu.m,
greater than or about 10 .mu.m, greater than or about 20 .mu.m,
greater than or about 30 .mu.m, greater than or about 40 .mu.m,
greater than or about 50 .mu.m, greater than or about 60 .mu.m,
greater than or about 70 .mu.m, greater than or about 80 .mu.m,
greater than or about 90 .mu.m, greater than or about 100 .mu.m, or
more. Consequently, the sheet resistance of shield members 410 may
be lower than the sheet resistance of sheet 420. Because shield
members 410 may be sized to specific coil sizes, the increased
conductivity may facilitate reductions in electrical noise, while
limiting reductions in magnetic fields or other mechanisms for
wireless charging.
[0052] Shield members 410 may include a body 412 and an appendage
414 from each shield member body 412. In the illustrated
embodiment, appendage 414 may constitute a conductive drain
extending from the shield member body 412, which may be similar to
the grounding pin previously described. The appendage 414 may also
be a bridge as will be described further below. Body 412 of each
shield member 410 may be sized and shaped to overlap an underlying
coil, and may be positioned when shield 400 is coupled with a
wireless power transmitting device to be axially aligned with an
underlying coil of the device as previously described. Body 412 may
include a gap 411 as discussed above, which may be formed from an
inner annular edge through an outer annular edge of the shield
member body, and which may form a discontinuity about a
circumference or perimeter of the shield member to reduce an impact
of eddy currents on the underlying coils. The location of the gap
may affect electrical fields, and in some embodiments the shield
members may be formed or positioned with consideration of the gap
location of other shield members in the shield. For example, in
some embodiments at least two shield members 410 may be arranged so
that a gap formed in each respective body 412 may face a gap in the
other shield member, which may be an adjacent shield member. Hence,
as illustrated, in some embodiments, shield members 410a and 410b
may be incorporated within shield 400 so that the gap in the
associated body of shield member 410a may face or be in line with
the gap in the associated body of shield member 410b.
[0053] Shield 400 may include at least one conductive drain
extending from at least one shield member 410 to the conductive
chassis 415. As illustrated, each appendage 414 shown in FIG. 4
forms a conductive drain extending from the body 412 of each shield
member 410 to the chassis 415, and/or another ground source, which
may include an underlying circuit board, for example. Each
appendage may be any of the previously described conductive
materials, and in some embodiments may be the same material as the
shield member bodies. The location and formation of the drains may
also affect emissions in different device configurations, and the
conductive drains may overlap underlying coils, which may further
impact charging efficiency of the associated device. For example,
in some embodiments the chassis 415 may distribute current to
coupling 417, where current may be delivered from the shield 400 to
an associated wireless power transmitting device, and in some
embodiments from a device to ground. The distance of travel from
each shield may impact the effect on emissions. Accordingly, in
some embodiments, additional appendage structures on the shields
may be used to limit the length of distribution paths, which may
improve emission reduction and/or effects on the wireless charging
efficiency of the associated device.
[0054] FIGS. 5A-5F show schematic plan views of exemplary shields
for a wireless power transmitting device according to some
embodiments of the present technology. The illustrations may
include variations on the shield structure of FIG. 4, and may
include some or all of the components as discussed with FIG. 4.
Although some of the illustrations do include a chassis, it is to
be understood that a chassis may be included to distribute current
as previously described, and the figures are more focused on
variations in the shield member and appendage structures of the
particular shield members. Any of the shields described below may
include any of the materials or components described elsewhere, and
may be incorporated with any of the wireless power transmitting
devices described. Additionally, any of the specifically
illustrated variations may be used in combination with other
variations, coil or shield member arrangements, or any wireless
power transmitting devices described elsewhere.
[0055] FIG. 5A illustrates a variation in the shield members in
which one appendage 505 is a conductive drain extending from the
body of the associated shield member to a conductive chassis and/or
other ground or current distribution path, such as an underlying
circuit board, for example. Each of the other appendages forms a
bridge between the bodies of two shield members. As shown,
appendage 510, as well as each other appendage but appendage 505,
includes a short trace of material extending from the body of one
shield member to the body of an adjacent shield member. FIG. 5A
shows a single arrangement with bridges, and it is to be understood
that any other organization of bridges is similarly encompassed
where each shield member body is coupled with another shield member
body.
[0056] Although utilizing bridges and a single drain may reduce the
amount of material, and may reduce some of the conductive paths,
such a configuration may also have a corresponding impact on
operational efficiency. For example, as previously described, an
associated wireless power transmitting device in which the shield
configuration illustrated may be used may operate to charge
multiple devices, such as a device positioned on opposite
longitudinal sides of the transmitting device. In such a scenario,
a coil underlying shield body 520a, and a coil underlying shield
body 520b may be selectively engaged. In the configuration of FIG.
5A, all current may be delivered from a single path through the
drain of appendage 505. Consequently, emissions collected on shield
body 520a and emissions collected on shield body 520b may all flow
towards one another and through appendage 505. However, depending
on the devices being charged simultaneously, the noise from one
charging may have some contributing effect on the noise from the
other device. In some beneficial scenarios, these noise components
may destructively cancel out, although in other scenarios some
amount of constructive development may occur, which may further
increase the generated noise, and reduce operating efficiency.
[0057] Consequently, including a combination of appendage
configurations including some number of drains, and some number of
bridges may improve these effects to accommodate a wider variety of
operating conditions. FIG. 5B illustrates one possible scenario in
which the same shield member body configuration may include an
alternate appendage design. As illustrated, each shield member is
electrically coupled with another shield member with a bridge,
and/or is electrically coupled to an external edge of the shield,
such as to a conductive chassis, with a conductive drain. This may
improve the effects produced by multiple devices being charged
simultaneously. As shown, the drains may be positioned towards a
side of the shield, such as a side along which a ground connection
may be made to an associated device as previously explained,
although the drains may also be coupled with the chassis in any
other location about the structure.
[0058] FIG. 5B also illustrates a shield body configuration in
which some shield bodies may be positioned similar to an adjacent
and inline shield body, and thus the gaps may be located at
corresponding positions relative to the shield. For example, shield
body 520c and shield body 520d may be positioned in line in a
similar orientation. Accordingly, gap 522c of shield body 520c may
be facing in a similar direction as the gap 522d of shield body
520d. FIGS. 4, 5A, and 5B illustrate some combinations for inline
shield bodies in which the gaps are positioned facing one another,
facing in opposite directions from one another, and facing in a
similar direction, respectively. Any combination of these
configurations may be used for different shield body pairs, or
multiples, which may provide different effects on emissions.
[0059] FIG. 5C illustrates a configuration in which a plurality of
slots 530 are formed on the shield body. As explained previously,
eddy currents may be induced on shields of the present technology.
Although a gap formed along the shield body may reduce eddy
currents, in some embodiments currents may still be circulating on
the shield body due to the lengths or areas of the shield bodies.
By forming a number of slots 530 on the shield body, eddy currents
may be reduced even further by introducing a more complicated path
about the shield. Slots 530 are shown as being defined by the
shield bodies from an inner annular edge of the shield body towards
an outer annular edge of the shield body, although the slots may
also be formed from the outer annular edge of the shield body
towards the inner annular edge of the shield body, as well as some
combination of slots extending inward and outward in other
embodiments.
[0060] Unlike a gap formed in each shield body, such as gap 522e,
slots 530 may not fully extend to the outer radial edge of the
shield body. Each shield body may define any number of slots, which
may be based on the size of the shield member body, although
exemplary configurations may include greater than or about 10
slots, greater than or about 50 slots, greater than or about 100
slots, greater than or about 500 slots, or more. FIG. 5C
illustrates a similar arrangement of appendages as FIG. 5A,
although it is to be understood that any shield member
configuration may incorporate slots 530, including any variation
illustrated, including shield members illustrated in FIG. 3A, as
well as any variation not expressly illustrated but encompassed by
the present technology as an adjustment to any of the illustrated
variations.
[0061] FIG. 5D illustrates another variation in which not all coils
of the top layer of coils in a layered configuration may include an
associated shield member. Such a configuration may also be applied
in any planar arrangement of coils as well, and is not intended to
be limited to layered configurations. Depending on the wireless
power transmitting device size, power, or configuration, few coils
may produce emissions to be controlled. In these scenarios, a
shield, which may include any of the characteristics of other
described shields, may include shield members that may cover only a
portion of the coils. For example, coil 501 of the illustrated
device may not contribute emissions to be addressed by a shield, or
may contribute emissions at a level that may be addressed by a
sheet, such as sheet 420 of an associated shield. The associated
shield may then include shield members over coils generating
greater emissions, such as a coil under shield member body 520f,
for example. Any number of variations on this design may be
utilized depending on the specific characteristics of a device and
the particular coils generating emissions to be addressed.
Additionally, FIG. 5D does not illustrate a sheet, such as sheet
420, to allow viewing of coils in a device with which the shield is
coupled. It is to be understood that the technology also
encompasses incorporation of a sheet and chassis, as well as any
other component previously described.
[0062] FIGS. 5E and 5F illustrate variations on particular
appendage designs, and may be used in combination with any of the
arrangements described elsewhere. For example, FIG. 5E illustrates
an embodiment in which appendage 535 does not connect
perpendicularly with chassis 537, but is angled towards a coupling
where current may be delivered from the shield. Angling appendages
may reduce path lengths, which may beneficially reduce emissions
characteristics. Angling some or all appendages may additionally
provide routes of conductive material to avoid underlying coil
positions. For example, the angle of appendage 535, or any other
appendage, may be selected to reduce the overlap with underlying
coils that are not the target of the particular shield body. FIG.
5F shows an additional design that may limit overlap with other
underlying coils by utilizing an arcuate appendage 540. Appendage
540 may be characterized by an arcuate shape that extends from a
shield body to the chassis, or another appendage or shield body.
The particular shape may be selected to limit overlap with an
underlying coil, which may be less than if a straight-member
conductive drain or bridge was utilized instead. The arcuate
appendage may increase path length in some configurations, which
may be balanced against the benefit of reducing overlap, to provide
the most benefit at the system level for reducing emissions.
[0063] FIG. 5G shows an additional shield configuration that may be
incorporated in any of the previously discussed designs. Shield
member 520g illustrates a gap 522f configuration in which the gap
may not extend in a linear direction radially across the shield
member, although still extending radially through the entire shield
member. Any number of configurations may be incorporated in various
embodiments in which the gap may be formed or a section may be
removed from a shield member in a number of ways. The gap may be
formed to accommodate underlying components, or may be formed to
provide particular performance characteristics, structural designs,
or to facilitate placement in a variety of devices. Accordingly, in
some embodiments the gap may be formed radially through a shield
member, and may extend linearly, in a stepped or angular pattern,
in an arcuate configuration as illustrated, or in any other manner
to form a continuous break through the shield member.
[0064] By incorporating shields according to the present
technology, emissions may be reduced or shifted from certain
frequencies. For example, by incorporating shields according to the
present technology, resonance associated with the coils may be
shifted to a lower frequency. By shifting the resonant frequency of
magnetic resonance emissions, emissions occurring at frequencies
associated with specific functionalities, such as object detection
on the transmission device, may be shifted to a lower frequency
where the excitation may be reduced. For example, some devices may
perform object detection on the transmission device at frequency
ranges below 30 MHz, for example, such as between about 20 MHz and
about 30 MHz, or between about 25 MHz and about 30 MHz.
Accordingly, any particular functionality of the transmission
device that may be occurring within these frequency ranges, may be
impacted or impeded by resonance occurring from the magnetic field.
However, by incorporating shield members over the coils may shift
the resonance out of the operating states of the device, which may
limit exciting the frequencies and impacting device operations.
[0065] FIGS. 6A and 6B show charts of emissions effects at a first
coil position and a second coil position for exemplary shields
according to some embodiments of the present technology. For
example, FIG. 6A may illustrate the effects of various designs on a
first coil in a top layer of coils on one side of the wireless
power transmitting device, and FIG. 6B may illustrate the effects
of various designs on a second coil in a top layer of coils on the
opposite side of the wireless power transmitting device. Line 605
shows the magnitude of the emissions of the first coil at different
frequencies without any shield incorporated, and line 625 shows the
magnitude of the emissions of the second coil at different
frequencies without any shield incorporated.
[0066] Line 610 shows the magnitude of emissions of the first coil
at different frequencies utilizing a shield structure similar to
the configuration illustrated in FIG. 4. As shown, the emissions at
30 MHz has been greatly reduced, and may limit issues with device
operation. The emissions at 25 MHz has been partly reduced,
although such a reduction may be sufficient for operations
performed closer to 30 MHz. Line 640 illustrates the magnitude of
emissions of the second coil at different frequencies utilizing the
shield structure similar to the configuration illustrated in FIG.
4. As shown, this shield configuration outperformed other shield
structures at the second coil.
[0067] Line 620 shows the magnitude of emissions of the first coil
at different frequencies utilizing a shield structure similar to
the configuration illustrated in FIG. 5A. As shown, the emissions
at 30 MHz and 25 MHZ has been greatly reduced, and the
configuration outperformed other shield structures at the first
coil. Line 630 illustrates the magnitude of emissions of the second
coil at different frequencies utilizing the shield structure
similar to the configuration illustrated in FIG. 5A. As shown, this
shield configuration reduced emissions at each frequency, although
the extent of reduction was less than other shield structures, and
overall, the performance of the shield structure may not improve on
other configurations.
[0068] Line 615 shows the magnitude of emissions of the first coil
at different frequencies utilizing a shield structure similar to
the configuration illustrated in FIG. 5B. As shown, the emissions
have been reduced at all frequencies, and is an improvement over
the configuration of FIG. 4 at lower frequencies, although not at
30 MHz. Line 635 illustrates the magnitude of emissions of the
second coil at different frequencies utilizing the shield structure
similar to the configuration illustrated in FIG. 5B. As shown, this
shield configuration reduced emissions at each frequency, and is an
improvement over the configuration of FIG. 5A at most frequencies,
although comparable closer to 30 MHz.
[0069] The charts of FIGS. 6A and 6B are intended to illustrate
that although certain configurations and appendage designs may
improve performance at certain coil locations, alternative designs
may provide more benefit at other coil locations. Accordingly,
depending on device operation frequencies, coil configurations, and
shield appendage configurations, an overall profile may be
developed for devices to provide emissions reductions at a system
level that affords an amount of benefit for performance against
different emission requirements, and to accommodate different
requirements, different configurations or modifications may be
incorporated. By utilizing shields according to the present
technology, field emissions of wireless power transmitting devices
may be reduced and device performance and efficiency may be
improved.
[0070] In the preceding description, for the purposes of
explanation, numerous details have been set forth in order to
provide an understanding of various embodiments of the present
technology. It will be apparent to one skilled in the art, however,
that certain embodiments may be practiced without some of these
details, or with additional details.
[0071] Having disclosed several embodiments, it will be recognized
by those of skill in the art that various modifications,
alternative constructions, and equivalents may be used without
departing from the spirit of the embodiments. Additionally, a
number of well-known processes and elements have not been described
in order to avoid unnecessarily obscuring the present technology.
Accordingly, the above description should not be taken as limiting
the scope of the technology.
[0072] Where a range of values is provided, it is understood that
each intervening value, to the smallest fraction of the unit of the
lower limit, unless the context clearly dictates otherwise, between
the upper and lower limits of that range is also specifically
disclosed. Any narrower range between any stated values or unstated
intervening values in a stated range and any other stated or
intervening value in that stated range is encompassed. The upper
and lower limits of those smaller ranges may independently be
included or excluded in the range, and each range where either,
neither, or both limits are included in the smaller ranges is also
encompassed within the technology, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included. Where multiple values are
provided in a list, any range encompassing or based on any of those
values is similarly specifically disclosed.
[0073] As used herein and in the appended claims, the singular
forms "a", "an", and "the" include plural references unless the
context clearly dictates otherwise. Thus, for example, reference to
"a material" includes a plurality of such materials, and reference
to "the coil" includes reference to one or more cells and
equivalents thereof known to those skilled in the art, and so
forth.
[0074] Also, the words "comprise(s)", "comprising", "contain(s)",
"containing", "include(s)", and "including", when used in this
specification and in the following claims, are intended to specify
the presence of stated features, integers, components, or
operations, but they do not preclude the presence or addition of
one or more other features, integers, components, operations, acts,
or groups.
* * * * *