U.S. patent application number 14/464888 was filed with the patent office on 2014-12-04 for mobile device with coupling area enhancement.
This patent application is currently assigned to TYFONE, INC.. The applicant listed for this patent is Tyfone, Inc.. Invention is credited to Saurav Chakraborty, Siva G. Narendra.
Application Number | 20140354503 14/464888 |
Document ID | / |
Family ID | 47068289 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140354503 |
Kind Code |
A1 |
Narendra; Siva G. ; et
al. |
December 4, 2014 |
MOBILE DEVICE WITH COUPLING AREA ENHANCEMENT
Abstract
A coupling area enhancement device includes a small coil and a
large coil on opposing sides of a sheet of electromagnetic
interference (EMI) absorptive material. The coupling area
enhancement device may include one or more holes and may include
adhesive material and sticker covers. Placement of the coupling
area enhancement device may be accomplished by sticking the small
coil to a host device near a contactless antenna. The large coil
may also be stuck to a battery cover.
Inventors: |
Narendra; Siva G.;
(Portland, OR) ; Chakraborty; Saurav; (West
Bengal, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tyfone, Inc. |
Portland |
OR |
US |
|
|
Assignee: |
TYFONE, INC.
Portland
OR
|
Family ID: |
47068289 |
Appl. No.: |
14/464888 |
Filed: |
August 21, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13097167 |
Apr 29, 2011 |
8843062 |
|
|
14464888 |
|
|
|
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Current U.S.
Class: |
343/842 |
Current CPC
Class: |
H04B 5/0081 20130101;
H01Q 1/48 20130101; H01Q 7/00 20130101; Y10T 29/49016 20150115;
G06K 7/10178 20130101; H01Q 1/526 20130101 |
Class at
Publication: |
343/842 |
International
Class: |
H01Q 1/52 20060101
H01Q001/52; H04B 5/00 20060101 H04B005/00; H01Q 7/00 20060101
H01Q007/00 |
Claims
1. A mobile device comprising: a communications chip; a mobile
device coil coupled to the communications chip; a sheet of
electromagnetic interference (EMI) absorptive material; a first
coil on a first side of the sheet of EMI absorptive material; and a
second coil on a second side of the sheet of EMI absorptive
material, wherein the second coil is coupled to the first coil, and
the second coil is larger than the first coil; wherein the sheet of
EMI absorptive material is positioned to align the first coil with
the mobile device coil.
2. The mobile device of claim 1 wherein the first coil is
electrically coupled to the second coil.
3. The mobile device of claim 1 wherein the first coil is
magnetically coupled to the second coil.
4. The mobile device of claim 1 wherein the sheet of EMI absorptive
material includes at least one hole.
5. The mobile device of claim 1 wherein the first coil is located
at one corner of the sheet of EMI absorptive material.
6. The mobile device of claim 1 wherein the first coil is located
at one edge of the sheet of EMI absorptive material.
7. The mobile device of claim 1 further comprising a plurality of
small coils on the first side.
8. The mobile device of claim 1 further comprising adhesive
material on the first side of the sheet of EMI absorptive
material.
9. The mobile device of claim 8 wherein the adhesive material is
placed to adhere a portion of the sheet of EMI absorptive material
corresponding to the first coil to a coupling area of the mobile
device coil.
10. The mobile device of claim 9 further comprising additional
adhesive material on the second side of the sheet of EMI absorptive
material, wherein an area of the additional adhesive material on
the second side is larger than an area of the adhesive material on
the first side.
11. A mobile device comprising: a communications chip; a mobile
device coil coupled to the communications chip; a flexible
substrate with electromagnetic interference (EMI) absorptive
qualities; a first coil on a first side of the flexible substrate;
and a second coil on the first side of the flexible substrate,
wherein the second coil is electrically coupled to the first coil,
and the second coil is larger than the first coil, the flexible
substrate being folded such that the first and second coils appear
to be on opposing sides; wherein the flexible substrate is
positioned to align the first coil with the mobile device coil.
12. The mobile device of claim 11 wherein mobile device comprises a
mobile phone.
13. The mobile device of claim 11 further comprising adhesive
material formed over the first coil to aid in locating the first
coil over the mobile device coil.
14. The mobile device of claim 13 further comprising additional
adhesive material formed over the second coil to aid in securing
the coupling area enhancement device.
15. The mobile device of claim 11 wherein the flexible substrate
has EMI absorptive qualities at substantially 13.56 MHz.
16. A mobile device comprising: a contactless device with a loop
antenna; and a coupling area enhancement device having a first coil
placed to couple to the loop antenna, a second coil larger than the
first coil and coupled to the first coil, and a sheet of
electromagnetic interference (EMI) absorptive material between the
first and second coils.
17. The mobile device of claim 16 wherein the first coil is
electrically coupled to the second coil.
18. The mobile device of claim 16 wherein the first coil is
magnetically coupled to the second coil.
19. The mobile device of claim 16 further comprising a memory card,
wherein the loop antenna is on the memory card.
20. The mobile device of claim 16 wherein the apparatus comprises a
mobile phone.
Description
FIELD
[0001] The present invention relates generally to transformer
coupling, and more specifically to the enhancement of coupling
area.
BACKGROUND
[0002] Small coils are being used as antennas for near field
communications (NCF). For example, mobile phones are incorporating
contactless smartcard circuits to read tags and communicate with
readers in mobile payment applications.
[0003] FIG. 1 shows a prior art mobile device 100 with a small coil
110 coupling to a large coil 120 in a reader device. FIG. 2 shows a
prior art transformer representation of the coils of FIG. 1. When
in the near field, coils 110 and 120 couple as transformer windings
as shown in FIG. 2. Because coil 110 is small, it presents a small
coupling area as compared to reader coil 120, and transformer
coupling is not very efficient. As a result, the mobile device
generally needs to be placed very close to a reader device in order
to effect communications.
[0004] FIG. 3 shows a prior art back-to-back transformer.
Back-to-back transformers are typically used for line isolation.
See Darren Ashbey et al., Circuit Design:Know It All 199-200
(2008).
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 shows a prior art mobile device with a small coil
coupling to a large coil in a reader device;
[0006] FIG. 2 shows a prior art transformer representation of the
coils of FIG. 1;
[0007] FIG. 3 shows a prior art back-to-back transformer;
[0008] FIGS. 4A and 4B show coupling area enhancement devices in
accordance with various embodiments of the present invention;
[0009] FIG. 5 shows an exploded view of a coupling area enhancer in
accordance with various embodiments of the present invention;
[0010] FIGS. 6A, 6B, 7A, and 7B show placement of coupling area
enhancement devices on mobile devices in accordance with various
embodiments of the present invention;
[0011] FIG. 8 shows a coupling area enhancement device having
magnetic coupling between small and large coils;
[0012] FIGS. 9-11 show coupling area enhancement devices with
various coil shapes and placements;
[0013] FIGS. 12A and 12B show a coupling area enhancement device
with a flexible substrate;
[0014] FIGS. 13A and 13B show placement of a coupling area
enhancement device on a mobile device in accordance with various
embodiments of the present invention;
[0015] FIGS. 14A and 14B show two sides of a coupling area
enhancement device with stickers and adhesive;
[0016] FIG. 15 shows placement of a coupling area enhancement
device inside a battery cover; and
[0017] FIG. 16 shows a flowchart of methods in accordance with
various embodiments of the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] In the following detailed description, reference is made to
the accompanying drawings that show, by way of illustration,
various embodiments of an invention. These embodiments are
described in sufficient detail to enable those skilled in the art
to practice the invention. It is to be understood that the various
embodiments of the invention, although different, are not
necessarily mutually exclusive. For example, a particular feature,
structure, or characteristic described in connection with one
embodiment may be implemented within other embodiments without
departing from the spirit and scope of the invention. In addition,
it is to be understood that the location or arrangement of
individual elements within each disclosed embodiment may be
modified without departing from the spirit and scope of the
invention. The following detailed description is, therefore, not to
be taken in a limiting sense, and the scope of the present
invention is defined only by the appended claims, appropriately
interpreted, along with the full range of equivalents to which the
claims are entitled. In the drawings, like numerals refer to the
same or similar functionality throughout the several views,
[0019] FIGS. 4A and 4B show coupling area enhancement devices in
accordance with various embodiments of the present invention. As
shown in FIG. 4A, coupling area enhancement device 400 includes
small coil 430, tuning capacitor 432, magnetic isolation 420, and
large coil 410. FIG. 4A also shows mobile device coil 110 and
reader coil 120.
[0020] Small coil 430 is sized to approximately match the size of
mobile device coil 110 to increase coupling to the mobile device
coil as compared to the coupling achieved in the prior art system
of FIG. 1. Large coil 410 is larger than either mobile device coil
110 or small coil 430. This increases the coupling to reader coil
120.
[0021] Magnetic isolation 420 is provided to ensure that any
surrounding metal does not render large coil 410 ineffective when
coupling area enhancement device 400 is attached to a mobile
device. In some embodiments, magnetic isolation 420 is provided
using an electromagnetic interference (EW) absorptive material. One
example is FerroxFoil from FerroxCube International Holding B.V. of
Eindhoven, The Netherlands.
[0022] In the prior art of back-to-back transformers (FIG. 3), the
step down secondary and the step up primary are not magnetically
isolated.
[0023] Small coil 430 and large coil 410 are connected by
conductors (electrically coupled) as shown in FIG. 4A. Parallel
tuning capacitor 432 is added to tune the circuit to be resonant at
a particular frequency. For example, in some embodiments, coupling
area enhancement device 400 is tuned to operate at 13.56 MHz, a
common frequency for contactless communications. Also for example,
in some embodiments, the EMI absorptive material absorbs energy at
the frequency to which the coils are tuned (e.g., 13.56 MHz).
[0024] In the embodiments represented by FIG. 4B, small coil 430
and large coil 410 are electrically coupled with a series tuning
capacitor 452. Any combination of parallel and/or series circuit
elements may be incorporate in coupling area enhancement devices
without departing from the scope of the present invention. The
choice and placement of tuning elements may depend in part on what
frequency range needs to be passed and/or stopped.
[0025] FIG. 5 shows an exploded view of a coupling area enhancement
device in accordance with various embodiments of the present
invention. Coupling area enhancement device 500 may include any of
the circuits shown above in FIGS. 4A and/or 4B. For example,
coupling area enhancement device 500 is shown with small coil 430,
large coil 410, and EMI absorptive material 520. EMI absorptive
material 520 functions as magnetic isolation 420 (FIG. 4). Coils
410 and 430 are shown electrically coupled through EMI absorptive
material 520. Series and/or parallel tuning elements may be
included (not shown).
[0026] Structurally, small coil 430 is on a first side 522 of EMI
absorptive material 520, and large coil 410 is on a second side 524
of EMI absorptive material 520. In some embodiments, absorptive
material is a flexible sheet, and coils 430 and 410 flex with the
sheet. Tuning capacitors and their connections may be on any side
or combination of sides. EMI absorptive material 520 may be any
shape, and may have holes or indentations to accommodate uneven
surfaces when attached to a. mobile device.
[0027] In operation, small coil 430 magnetically couples with a
small coil on a mobile device, such as coil 110 (FIG. 1).
Substantial coupling takes place as long as the two coils are
aligned, because the two coils are not greatly mismatched in size.
Large coil 410 is connected to the small coil 430 through the
electrical coupling described above, and then large coil 410
magnetically couples to a coil on a reader device. Through this
operation, an increased coupling area (that of large coil 410) is
presented to a reader. Hence, the device is referred to as a
coupling area enhancement device.
[0028] FIGS. 6A, 6B, 7A, and 7B show placement of coupling area
enhancement devices on mobile devices in accordance with various
embodiments of the present invention.
[0029] FIG. 6A shows coupling area enhancement device 500 aligned
such that small coil 430 will be placed over mobile device coil 110
when attached. When attached to mobile device 100 (FIG. 6B),
coupling area enhancement device 500 has side 522 with small coil
430 facing the mobile device. Side 524 is facing out with large
coil 410 exposed for coupling to a reader.
[0030] In some embodiments, mobile device 100 includes a
contactless device along with small coil 110 to effect
communications. For example, mobile device 100 may be a mobile
phone or tablet computer with a dual interface smartcard chip or a
near-field communications (NFC) chip coupled to coil 110. In other
embodiments, coil 110 is provided in mobile device 100, and a
contactless device is included in an add-on card such as a memory
card or subscriber identity module (SIM).
[0031] In some embodiments, an adhesive is applied to a portion, or
all, of side 522 prior to attaching coupling are enhancement device
500 to mobile device 100.
[0032] When small coil 430 is aligned with the mobile device small
coil 110, the effective area for coupling to the reader is now
increased to a larger area compared to the prior art shown in FIG.
1. This allows for an enhanced consumer experience in part because
the consumer does not have to tap or swipe a specific area of the
mobile device to the reader.
[0033] FIG. 7A shows coupling area enhancement device 500 aligned
with mobile device 700 such that small coil 430 will be placed over
all or a portion of add-on card 710. In some embodiments, add-on
card 710 is a memory card that includes a contactless device with a
loop antenna. Further, in some embodiments, add-on card 710 is a
subscriber identity module (SIM) card with a contactless device and
loop antenna. For example, the contactless device may include a
dual interface smartcard chip or a near-field communications (NFC)
chip, and the loop antenna may be a small wire loop wound around a
magnetic material.
[0034] Although add-on card 710 is shown on the back of mobile
device 700, the location of the add-on card or the need for the
add-on card to be present to provide the described functionality is
not a limitation of the present invention. Add-on card 710 may be
anywhere on or in mobile device 700. For example, in some
embodiments, add-on card 710 is a MicroSD memory card that is in a
memory card slot of a mobile phone or tablet computer. Also for
example, in some embodiments, add-on card 710 may be a memory card
or SIM card stored behind a battery cover of a mobile phone or
tablet computer. Also for example, in some embodiment, all of the
pertinent functions of the add-on card 710 may be embedded directly
in the mobile device.
[0035] When attached to mobile device 700 (FIG. 7B), coupling area
enhancement device 500 has side 522 with small coil 430 facing the
mobile device. Side 524 is facing out with large coil 410 exposed
for coupling to a reader.
[0036] Mobile device 700 (and mobile device 100) may be any type of
mobile device. For example, mobile device 700 may be a mobile
phone, a portable media player, a tablet computer, a sleeve that
accepts another mobile device, or the like. The various embodiments
of coupling area enhancement devices may be used to enhance the
coupling area of any type of device without departing from the
scope of the present invention.
[0037] FIG. 8 shows a coupling area enhancement device having
magnetic coupling between small and large coils. Coupling area
enhancement device 800 includes small coil 430 and tuning capacitor
810 on one side of the magnetic isolation, Coupling area
enhancement device 800 also includes large coil 410 and tuning
capacitor 820 on a second side of the magnetic isolation.
[0038] In embodiments represented by FIG. 8, small coil 430 is
tuned with capacitor 810 and large coil 410 is tuned separately
with capacitor 820. The two coils couple to each other through the
magnetic isolation EMI absorber (magnetic coupling), which acts
like the core of a transformer, except in this case each of the
coils are tuned to a specific frequency range of interest.
[0039] Any of the coupling area enhancement devices described
herein may be magnetically coupled as shown in FIG. 8, or
electrically coupled as shown in FIGS. 4A and 4B.
[0040] FIGS. 9-11 show coupling area enhancement devices with
various coil shapes and placements. FIG. 9 shows coupling area
enhancement device 900 with EMI absorptive sheet 920, large coil
910, and small coil 930. The shape of the coupling area enhancement
devices or the coils need not be rectangular or a square. For
example, as shown in FIG. 9, the EMI absorptive sheet is an
irregular shape, as are the coils. Further, the various embodiments
of the invention are not limited by the relative position of the
small coil to the large coil. For example, in some embodiments, the
small coil is located in a corner or along one side. Because
different mobile devices may have coils in various different
locations, the small coil may be located anywhere on the EMI
absorptive sheet so that it may couple to mobile device coil.
[0041] FIG. 10 shows another coupling area enhancement device 1000.
Coupling area enhancement device 1000 includes EMI absorptive
material 1020, small coil 1030, and large coil 1010. Small coil
1020 is located at the end of an appendage of EMI absorptive
material 1020. In some embodiments, this is useful when the mobile
device coil is not located in a spot that can easily or
ergonomically accommodate the entire coupling area enhancement
device. For example, the mobile device coil may be along side a
touchscreen, under a keyboard, or the like.
[0042] FIG. 11 show another coupling area enhancement device 1100.
Coupling area enhancement device 1100 includes large coil 910, EMI
absorptive sheet 920, and small coil 930. Coupling area enhancement
circuit 1100 also includes additional small coils 1132 and 1134. As
shown in FIG. 11, some embodiments of coupling area enhancement
devices include more than one small coil. One of the small coils
may be used to couple to a coil on a mobile device. Or one small
coil may couple to one add-on card and a second small coil may
couple to another add-on card or directly to a small coil on the
mobile device. Similarly, some embodiments include multiple large
coils for one small coil or for multiple small coils.
[0043] FIGS. 12A and 12B show a coupling area enhancement device
with a flexible substrate. Coupling area enhancement device 1200
includes flexible EMI absorptive sheet 1220 (the substrate), large
coil 1210, and small coil 1230. As shown in FIG. 12A, small coil
1230 and large coil 1210 may be on the same side of the flexible
EMI absorptive sheet but apart from each other when manufactured.
As shown in FIG. 12B, the flexible EMI absorptive sheet may be
folded such that the flexible substrate creates a structure with
small coil 1230 and large coil 1210 on opposing sides. The folding
may occur prior to, or concurrently with, installing in the mobile
device.
[0044] FIGS. 13A and 13B show placement of a coupling area
enhancement device on a mobile device in accordance with various
embodiments of the present invention. Mobile device 1300 includes
add-on card 710 and accessory device 1310. Coupling area
enhancement device 1350 includes large coil 410, small coil 430,
and EMI absorptive sheet 1360 with hole 1320.
[0045] As shown in FIG. 13B, hole 1320 aligns with accessory device
1310 when coupling area enhancement device 1350 is attached.
Accessory device 1310 may be any type of device that can
advantageously be aligned with hole 1320. For example, accessory
device 1310 may be a speaker, microphone, light sensor, display,
camera, or the like. Any number of accessory devices may be
accommodated by any number holes, indentations, protrusion, or the
like within any of the coupling area enhancement devices described
herein.
[0046] FIGS. 14A and 14B show two sides of a coupling area
enhancement device with stickers and adhesive. FIG. 14A shows an
exploded view of coupling area enhancement device 500 and sticker
cover 1410. Sticker cover 1410 covers all or a portion of face 524.
In some embodiments, adhesive is applied to either or both of face
524 and sticker cover 1410 before applying sticker cover 1410 to
face 524. When sticker cover 1410 is removed from face 524, the
adhesive remains and face 524 will adhere to any surface that is
pressed against it.
[0047] FIG. 14B shows an exploded view of coupling area enhancement
device 500 and sticker cover 1420. Sticker cover 1420 covers all or
a portion of face 522. In some embodiments, adhesive is applied to
either or both of face 522 and sticker cover 1420 before applying
sticker cover 1420 to face 522. When sticker cover 1420 is removed
from face 522, the adhesive remains and face 522 will adhere to any
surface that is pressed against it.
[0048] In some embodiments, sticker covers 1410 and 1420 are
different sizes. For example, sticker cover 1420 may be roughly the
same size as coil 430 or may be much smaller. Also for example,
sticker cover 1410 may be quite large such that to most if not all
of face 524 has exposed adhesive when cover 1410 is removed. As
described further below, the different sizes of sticker covers may
aid in the placement of the coupling area enhancement device
relative to a small coil in a mobile device. Some embodiments
include multiple sticker covers on one or both faces.
[0049] In some embodiments, adhesive and sticker covers are only
placed on one side of the EMI absorptive material. For example,
referring now back to FIG. 12, a small sticker cover may be placed
over small coil 1230, and a larger sticker cover may be placed over
large coil 1210.
[0050] FIG. 15 shows placement of a coupling area enhancement
device inside a battery cover. Mobile device 1500 is shown with
battery cover 1510 removed. With battery cover 1510 removed,
battery 1520 and add-on card 710 are exposed. Coupling area
enhancement device 500 has been adhered to the inside of battery
cover 1510 and has been oriented such that face 522 is exposed and
small coil 430 aligns with a loop antenna in add-on card 710. When
battery cover 1510 is replaced on mobile device 1500 with coupling
area enhancement device 500 placed and oriented as shown, the
coupling area of add-on card 710 is substantially enhanced.
[0051] In some embodiments, coupling area enhancement device 500 is
adhered directly to battery cover 1510 by peeling off sticker cover
1410 (FIG. 14) and pressing it to the battery cover. In other
embodiments, sticker cover 1420 is first peeled off and coupling
area enhancement device 500 stuck to add-on card to better align
the add-on card with small coil 430. Sticker cover 1410 is then
peeled off and battery cover 1510 is replaced. This is described in
more detail below with reference to FIG. 16.
[0052] FIG. 16 shows a flowchart of methods in accordance with
various embodiments of the present invention. In some embodiments,
method 1600 may be performed when orienting a coupling area
enhancement device relative to a small coil on a mobile device. The
various actions in method 1600 may be performed in the order
presented, in a different order, or simultaneously. Further, in
some embodiments, some actions listed in FIG. 16 are omitted from
method 1600.
[0053] Method 1600 begins at 1610 in which a battery cover is
removed from a mobile device. This corresponds to battery cover
1510 being removed from mobile device 1500. In some embodiments,
the battery cover is not removed. For example, mobile device 1500
may have an add-on card slot in the front or one of the perimeter
sides. At 1620, an add-on card is inserted. This corresponds to
inserting add-on card 710 into mobile device 1500. In some
embodiments, an add-on card is not inserted. For example, mobile
device 1500 may already include a coil or loop antenna.
[0054] At 1630, a sticker cover is removed from a small coil on a
first side of the coupling area enhancement device to reveal a
small sticky portion. This corresponds to removing sticker cover
1420 to reveal a sticky portion covering small coil 430. In some
embodiments, multiple small coils exist and multiple sticker covers
exist. For example, a single coupling area enhancement device may
be used for multiple different types of mobile devices with coils
in different locations. Also for example, a mobile device may have
more than one coil. In these embodiments, which sticker to be
removed is dictated by the location of the coil.
[0055] In the case of add-on cards and microSD cards, the
contactless antenna will often be the only exposed edge of the card
once it is inserted. In the case of the contactless antenna being
built-in to the mobile device, it may be anywhere and marked.
[0056] At 1640, the coupling area enhancement device is placed with
the first sticky portion oriented on top of a contactless antenna
in a mobile device. This corresponds to coupling area enhancement
device 500 being placed against mobile device 1500 with battery
cover 1510 removed such that coil 430 aligns with an antenna in
add-on card 710.
[0057] At 1650, a second sticker cover is removed from a large coil
on a second side of the coupling area enhancement device to reveal
a second sticky portion. This corresponds to removing sticker cover
1410 from face 524. At this point in method 1600, coupling area
enhancement device 500 is attached to mobile device 1500 with an
adhesive surface exposed and the battery cover removed.
[0058] At 1660, the battery cover is replaced over the second
sticky portion, and at 1670, the battery cover is pressed in place
to have the second sticky portion adhere to the battery cover.
[0059] Once the coupling area enhancement device is stuck on the
battery cover, pulling the battery cover at 1680 will release the
first sticky portion since the surface area of the second sticky
portion is greater than the surface area of the first sticky
portion. In some embodiments, different types of adhesives are used
on the two sides of the coupling area enhancement device to aid in
the release of the first sticky portion when the battery cover is
removed.
[0060] At this point in method 1600, coupling area enhancement
device 500 is adhered to battery cover 1510 and aligned such that
small coil 430 aligns with a contactless antenna in add-on card
710. At 1690, the battery cover is replaced.
[0061] Although the present invention has been described in
conjunction with certain embodiments, it is to be understood that
modifications and variations may be resorted to without departing
from the spirit and scope of the invention as those skilled in the
art readily understand. Such modifications and variations are
considered to be within the scope of the invention and the appended
claims.
* * * * *