U.S. patent application number 17/104918 was filed with the patent office on 2022-05-26 for touch sensors with multi-state electrodes.
This patent application is currently assigned to IDEX Biometrics ASA. The applicant listed for this patent is IDEX Biometrics ASA. Invention is credited to Imre KNAUSZ.
Application Number | 20220164085 17/104918 |
Document ID | / |
Family ID | |
Filed Date | 2022-05-26 |
United States Patent
Application |
20220164085 |
Kind Code |
A1 |
KNAUSZ; Imre |
May 26, 2022 |
TOUCH SENSORS WITH MULTI-STATE ELECTRODES
Abstract
In some embodiments, a method for detecting a portion of a
user's body may be provided. The method may be performed by a
system comprising a plurality of cells, each cell of the plurality
of cells comprising a transmit electrode and a receive electrode.
The method may include, in a first timeslot, applying a first
driving signal to the transmit electrode of a first cell, and
receiving a first measurement signal using the receive electrode of
the first cell. The method may further include, in a second
timeslot, applying a second driving signal to the transmit
electrode of the first cell, and receiving a second measurement
signal using the receive electrode of the first cell. The second
driving signal may be inverted relative to the first driving
signal.
Inventors: |
KNAUSZ; Imre; (Fairport,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDEX Biometrics ASA |
Oslo |
|
NO |
|
|
Assignee: |
IDEX Biometrics ASA
Oslo
NO
|
Appl. No.: |
17/104918 |
Filed: |
November 25, 2020 |
International
Class: |
G06F 3/041 20060101
G06F003/041; G06F 3/044 20060101 G06F003/044 |
Claims
1. A method for detecting a portion of a user's body, the method
being performed by a system comprising a plurality of cells, each
cell of the plurality of cells comprising a respective transmit
electrode that is specific to that cell and a receive electrode,
the plurality of cells comprising a first cell, wherein the method
comprises: in a first timeslot: applying a first driving signal to
the transmit electrode of the first cell; and receiving a first
measurement signal using the receive electrode of the first cell;
and in a second timeslot: applying a second driving signal to the
transmit electrode of the first cell; and receiving a second
measurement signal using the receive electrode of the first cell;
wherein the second driving signal is inverted relative to the first
driving signal.
2. The method of claim 1, wherein the plurality of cells comprises
a first set of cells, the first set of cells comprising at least
the first cell and a second cell, each receive electrode of the
first set of cells being electrically connected to a first output
line, the method further comprising: in the first timeslot:
applying the second driving signal to the transmit electrode of the
second cell while the first driving signal is applied to the
transmit electrode of the first cell; and receiving the first
measurement signal using the first output line, the first output
line being electrically connected to the receive electrodes of both
the first cell and the second cell; in the second timeslot:
applying the first driving signal to the transmit electrode of the
second cell while the second driving signal is applied to the
transmit electrode of the first cell; and receiving the second
measurement signal using the first output line, the first output
line being electrically connected to the receive electrodes of both
the first cell and the second cell.
3. The method of claim 2, wherein the plurality of cells comprises
a second set of cells, wherein no driving signal is applied to the
second set of cells during the first timeslot or the second
timeslot.
4. The method of claim 3, wherein the first set of cells is
arranged in a first linear array, the second set of cells is
arranged in a second linear array, and the first linear array is
adjacent to the second linear array such that each cell of the
first set is adjacent to a respective cell of the second set.
5. The method of claim 2, wherein each cell of the first set of
cells has a first state and a second state, wherein: in the first
state, the transmit electrode of the respective cell is selectively
connected to a first drive line that is configured to apply the
first driving signal; and in the second state, the transmit
electrode of the respective cell is selectively connected to a
second drive line that is configured to apply the second driving
signal.
6. The method of claim 5, wherein the method comprises: applying
the first and second states to the first set of cells over a
plurality of timeslots according to a multiplexing pattern;
receiving a plurality of measurement signals using the first output
line, wherein a respective measurement signal is received in each
timeslot of the plurality of timeslots; and processing the
plurality of measurement signals to obtain a respective measurement
for each cell of the first set of cells.
7. The method of claim 6, wherein the plurality of cells comprises
a second set of cells, each receive electrode of the second set
being connected to a second output line, each cell of the second
set of cells having a first state and a second state, wherein: in
the first state, the transmit electrode of the respective cell of
the second set is selectively connected to a first drive line of
the second set that is configured to apply the first driving
signal; and in the second state, the transmit electrode of the
respective cell of the second set is selectively connected to a
second drive line of the second set that is configured to apply the
second driving signal; the method further comprising: applying the
first and second states to the second set of cells over the
plurality of timeslots according to a multiplexing pattern, the
application of the first and second states to the second set of
cells occurring simultaneously with the application of the first
and second states to the first set of cells; receiving a plurality
of measurement signals using the second output line, wherein a
respective measurement signal is received using the second output
line in each timeslot of the plurality of timeslots; and processing
the plurality of measurement signals received using the second
output line to obtain a respective measurement for each cell of the
second set of cells.
8. The method of claim 7, wherein the first output line and the
second output line are connected to a common analog front end
during the plurality of timeslots.
9. The method of claim 8, further comprising: encoding the
measurement signals received using the first output line and the
measurement signals received using the second output line during
the first plurality of timeslots, such that the encoded measurement
signals are configured be combined and decoded to separate the
measurement signals received using the first output line from the
measurements received using the second output line.
10. The method of claim 2, the method further comprising: obtaining
measurements from at least the cells of the first set of cells in a
first set of timeslots; and obtaining measurements from one or more
additional sets of cells of the plurality of cells in one or more
subsequent sets of timeslots until at least one measurement has
been obtained from each cell of the plurality of cells.
11. A system for detecting a portion of a user's body, the system
comprising: a plurality of cells comprising at least a first cell
and a second cell, wherein: each cell of the plurality of cells
comprises a respective transmit electrode that is specific to that
cell, the respective transmit electrode being configured to
selectively apply a first driving signal, the respective transmit
electrode being further configured to selectively apply a second
driving signal that is inverted relative to the first driving
signal; each cell of the plurality of cells further comprises a
respective receive electrode; and the system is configured to:
apply, in a first timeslot, the first driving signal to the
transmit electrode of the first cell; and receive, in the first
timeslot, a first measurement signal using the receive electrode of
the first cell; and apply, in a second timeslot, the second driving
signal to the transmit electrode of the first cell; and receive, in
the second timeslot, a second measurement signal using the receive
electrode of the first cell.
12. The system of claim 11, wherein: the plurality of cells
comprises a first set of cells, the first set of cells comprising
at least the first cell and a second cell; each receive electrode
of the first set of cells is electrically connected to a first
output line; and the system is further configured to: apply, in the
first timeslot, the second driving signal to the transmit electrode
of the second cell while the first driving signal is applied to the
transmit electrode of the first cell; and receive, in the first
timeslot, the first measurement signal using the first output line,
the first output line being electrically connected to the receive
electrodes of both the first cell and the second cell; apply, in
the second timeslot, the first driving signal to the transmit
electrode of the second cell while the second driving signal is
applied to the transmit electrode of the first cell; and receive,
in the second timeslot, the second measurement signal using the
first output line, the first output line being electrically
connected to the receive electrodes of both the first cell and the
second cell.
13. The system of claim 12, wherein the plurality of cells
comprises a second set of cells, the system being configured to
apply no driving signal to the second set of cells during the first
timeslot or the second timeslot.
14. The system of claim 13, wherein the first set of cells is
arranged in a first linear array, the second set of cells is
arranged in a second linear array, and the first linear array is
adjacent to the second linear array such that each cell of the
first set is adjacent to a respective cell of the second set.
15. The system of claim 12, wherein each cell of the first set of
cells has a first state and a second state, such that: in the first
state, the transmit electrode of the respective cell is selectively
connected to a first drive line that is configured to apply the
first driving signal; and in the second state, the transmit
electrode of the respective cell is selectively connected to a
second drive line that is configured to apply the second driving
signal.
16. The system of claim 15, wherein the system is configured to:
apply the first and second states to the first set of cells over a
plurality of timeslots according to a multiplexing pattern; receive
a plurality of measurement signals using the first output line,
wherein a respective measurement signal is received in each
timeslot of the plurality of timeslots; and process the plurality
of measurement signals to obtain a respective measurement for each
cell of the first set of cells.
17. The system of claim 16, wherein: the plurality of cells
comprises a second set of cells; each receive electrode of the
second set is connected to a second output line; each cell of the
second set of cells has a first state and a second state, such
that: in the first state, the transmit electrode of the respective
cell of the second set is selectively connected to a first drive
line of the second set that is configured to apply the first
driving signal; and in the second state, the transmit electrode of
the respective cell of the second set is selectively connected to a
second drive line of the second set that is configured to apply the
second driving signal; and the system is configured to: apply the
first and second states to the second set of cells over the
plurality of timeslots according to a multiplexing pattern, the
application of the first and second states to the second set of
cells occurring simultaneously with the application of the first
and second states to the first set of cells; receive a plurality of
measurement signals using the second output line, wherein a
respective measurement signal is received using the second output
line in each timeslot of the plurality of timeslots; and process
the plurality of measurement signals received using the second
output line to obtain a respective measurement for each cell of the
second set of cells.
18. The system of claim 17, wherein the first output line and the
second output line are connected to a common analog front end
during the plurality of timeslots.
19. The system of claim 18, wherein the system is further
configured to: encode the measurement signals received using the
first output line and the measurement signals received using the
second output line during the first plurality of timeslots, such
that the encoded measurement signals are configured be combined and
decoded to separate the measurement signals received using the
first output line from the measurements received using the second
output line.
20. The system of claim 12, wherein the system is further
configured to: obtain measurements from at least the cells of the
first set of cells in a first set of timeslots; and obtain
measurements from one or more additional sets of cells of the
plurality of cells in one or more subsequent sets of timeslots
until at least one measurement has been obtained from each cell of
the plurality of cells.
Description
FIELD OF THE DISCLOSURE
[0001] This disclosure relates to sensors for the electronic
sensing of objects located near or about a sensor, such as a
position of a finger or features thereof.
BACKGROUND
[0002] Sensors may be used for detecting the presence of objects
located near or about a sensor. Such sensors can be configured to
sense electrical characteristics of an object in order to sense
presence or location of an object near or about the sensor,
physical characteristics of the object, shapes, textures on
surfaces of an object, material composition, biological
information, and other features and characteristics of an object
being sensed. For example, a sensor may be configured to detect the
presence or position of a user's finger, or in the exemplary case
of a fingerprint sensor, one or more features (for example, ridges)
of a user's finger.
[0003] Capacitive touch sensors (as used herein, the term "touch
sensor" encompasses any sensor that is configured to detect the
presence or position of a finger or other portion of a user's body,
and includes but is not limited to fingerprint sensors) may be
designed as mutual capacitance sensors or self-capacitance sensors.
In some self-capacitance sensors, a grid of electrodes may be
arranged, where each electrode represents a respective pixel.
Self-capacitance sensors may offer superior image quality relative
to mutual capacitance sensors, among other benefits.
Self-capacitance sensors have had limitations, however, insofar as
they have typically required drive rings or dedicated electrodes
which apply a driving signal to the user's finger. These drive
rings and/or dedicated drive electrodes can increase the size and
cost of the sensor, and when incorporated within the sensor grid,
they can create regions of the sensor that are not responsive to
touch. Additionally, in embodiments where every pixel corresponds
to an independent electrode, it can be difficult to route the
received signals from each electrode to receiving circuitry for
analysis, particularly as the size of the sensor grid
increases.
[0004] Accordingly, there is a need for self-capacitance sensors
that can be operated without the use of a drive ring or dedicated
drive electrodes, and which may also provide for improved signal
routing.
SUMMARY
[0005] The following presents a simplified summary in order to
provide a basic understanding of some aspects described herein.
This summary is not an extensive overview of the claimed subject
matter. It is intended to neither identify key or critical elements
of the claimed subject matter nor delineate the scope thereof. Its
sole purpose is to present some concepts in a simplified form as a
prelude to the more detailed description that is presented
later.
[0006] In some embodiments, a method for detecting a portion of a
user's body may be provided. The method may be performed by a
system comprising a plurality of cells, each cell of the plurality
of cells comprising a transmit electrode and a receive electrode.
The method may include, in a first timeslot, applying a first
driving signal to the transmit electrode of a first cell, and
receiving a first measurement signal using the receive electrode of
the first cell. The method may further include, in a second
timeslot, applying a second driving signal to the transmit
electrode of the first cell, and receiving a second measurement
signal using the receive electrode of the first cell. The second
driving signal may be inverted relative to the first driving
signal.
[0007] In another embodiment, a system for detecting a portion of a
user's body may be provided. The system may include a plurality of
cells comprising at least a first cell and a second cell. In some
embodiments, each cell of the plurality of cells may include a
respective transmit electrode that is configured to selectively
apply a first driving signal. The respective transmit electrode may
be further configured to selectively apply a second driving signal
that is inverted relative to the first driving signal. In some
embodiments, each cell of the plurality of cells may further
include a respective receive electrode. The system may be
configured to apply, in a first timeslot, the first driving signal
to the transmit electrode of the first cell, and receive, in the
first timeslot, a first measurement signal using the receive
electrode of the first cell. The system may be further configured
to apply, in a second timeslot, the second driving signal to the
transmit electrode of the first cell, and receive, in the second
timeslot, a second measurement signal using the receive electrode
of the first cell.
[0008] Further variations encompassed within the systems and
methods are described in the detailed description of the invention
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings, which are incorporated herein and
form part of the specification, illustrate various, non-limiting
embodiments of the present invention. In the drawings, like
reference numbers indicate identical or functionally similar
elements.
[0010] FIG. 1 depicts an exemplary schematic of a touch sensor.
[0011] FIGS. 2A and 2B illustrate a sensor in which an exemplary
modulation technique is used to perform measurements using the
electrodes.
[0012] FIG. 3 is a schematic diagram showing exemplary circuitry
for providing states such as those shown in FIGS. 2A and 2B.
[0013] FIGS. 4A and 4B illustrate a sensor in which another
exemplary modulation technique is used to perform measurements.
[0014] FIG. 5 shows a schematic for an exemplary multi-state
electrode.
[0015] FIG. 6 shows an exemplary schematic of a sensor having a
grid of multi-state electrodes.
[0016] FIG. 7 shows another exemplary schematic of a sensor having
a grid of multi-state electrodes.
[0017] FIG. 8A is a plan-view looking down on an exemplary
multi-state electrode 110.
[0018] FIG. 8B shows a cross-sectional view of the same electrode
110 taken at line 8B-8B.
[0019] FIG. 9 illustrates another exemplary arrangement for a
system having multi-state electrodes.
[0020] FIG. 10 illustrates another exemplary arrangement for a
system having multi-state electrodes.
[0021] FIGS. 11A-11B illustrate another exemplary arrangement for a
system having multi-state electrodes.
[0022] FIG. 12 illustrates a figurative diagram of an exemplary
sensor system.
[0023] FIG. 13 illustrates an exemplary method 500 for performing
measurements using a sensor system with multi-state electrodes.
[0024] FIG. 14 illustrates another exemplary embodiment for a
sensor.
[0025] FIG. 15 illustrates an exemplary method 600 for detecting a
portion of a user's body or other element.
DETAILED DESCRIPTION
[0026] While aspects of the subject matter of the present
disclosure may be embodied in a variety of forms, the following
description and accompanying drawings are merely intended to
disclose some of these forms as specific examples of the subject
matter. Accordingly, the subject matter of this disclosure is not
intended to be limited to the forms or embodiments so described and
illustrated.
[0027] Unless defined otherwise, all terms of art, notations and
other technical terms or terminology used herein have the same
meaning as is commonly understood by one of ordinary skill in the
art to which this disclosure belongs. All patents, applications,
published applications and other publications referred to herein
are incorporated by reference in their entirety. If a definition
set forth in this section is contrary to or otherwise inconsistent
with a definition set forth in the patents, applications, published
applications, and other publications that are herein incorporated
by reference, the definition set forth in this section prevails
over the definition that is incorporated herein by reference.
[0028] Unless otherwise indicated or the context suggests
otherwise, as used herein, "a" or "an" means "at least one" or "one
or more."
[0029] This description may use relative spatial and/or orientation
terms in describing the position and/or orientation of a component,
apparatus, location, feature, or a portion thereof. Unless
specifically stated, or otherwise dictated by the context of the
description, such terms, including, without limitation, top,
bottom, above, below, under, on top of, upper, lower, left of,
right of, in front of, behind, next to, adjacent, between,
horizontal, vertical, diagonal, longitudinal, transverse, radial,
axial, etc., are used for convenience in referring to such
component, apparatus, location, feature, or a portion thereof in
the drawings and are not intended to be limiting.
[0030] Furthermore, unless otherwise stated, any specific
dimensions mentioned in this description are merely representative
of an exemplary implementation of a device embodying aspects of the
disclosure and are not intended to be limiting.
[0031] As used herein, the term "adjacent" refers to being next to
or adjoining.
[0032] As used herein, the terms "substantially" and "substantial"
refer to a considerable degree or extent. When used in conjunction
with, for example, an event, circumstance, characteristic, or
property, the terms can refer to instances in which the event,
circumstance, characteristic, or property occurs precisely as well
as instances in which the event, circumstance, characteristic, or
property occurs to a close approximation, such as accounting for
typical tolerance levels or variability of the embodiments
described herein.
[0033] As used herein, the terms "optional" and "optionally" mean
that the subsequently described, component, structure, element,
event, circumstance, characteristic, property, etc. may or may not
be included or occur and that the description includes instances
where the component, structure, element, event, circumstance,
characteristic, property, etc. is included or occurs and instances
in which it is not or does not.
[0034] As used herein, the term "noise" broadly includes
disturbances generated by any of various random processes (e.g.,
flicker noise, shot noise) and also to interference that is
substantially not correlated with the signals being acquired nor
with the acquisition method.
[0035] The present disclosure may be incorporated into any suitable
sensor, as will be understood by those of skill in the art. Such
exemplary sensors may include touch screens, fingerprint sensors,
or other sensors configured to detect the position of an object or
feature thereof. For purposes of illustration, and not by way of
limitation, the disclosure below discusses embodiments of
two-dimensional sensors configured to detect the location of a
user's finger or portion thereof.
[0036] In sensors such as touch screens and fingerprint sensors,
noise can interfere with measurement accuracy. It is therefore
desirable to minimize noise to the extent possible. For example, in
U.S. Pat. No. 9,779,280, which is incorporated by reference herein
in its entirety, a system combining reference and compensation
electrodes with differential amplifiers is used to improve the
rejection of typical conducted and radiated noise sources found in
sensors such as fingerprint sensors. As disclosed in U.S. patent
application Ser. Nos. 15/869,214 and 16/108,875, signals
corresponding to groups of pixels may be modulated and demodulated
according to patterns in order to compensate for common mode noise.
Disclosed in the present application are sensors and modulation
techniques that can be used to obtain data with improved
signal-to-noise ratio (SNR) and/or signal-to-interference ratio
(SIR), and at reduced cost. These sensors and modulation techniques
may optionally be used in combination with the techniques disclosed
in U.S. Pat. No. 9,779,280 and U.S. patent application Ser. Nos.
15/869,214 and 16/108,875.
[0037] FIG. 1 depicts an exemplary schematic of a touch sensor 100.
In this embodiment, the sensor 100 is illustrated as a
self-capacitance sensor with an active substrate. The sensor may
include one or more electrodes 110, which may be configured to
capacitively couple to a user's finger or other element to be
sensed. The resulting signal from the one or more electrodes 110
may be transmitted to a receiver 128, which may be, in some
embodiments, an analog front end (AFE).
[0038] In some embodiments, one or more receivers 128 may be
arranged to receive signals from a number of electrodes 110. In
such cases, it may be advantageous to provide circuitry so that the
source of any given signal may be determined, thereby allowing the
received signal to be mapped against a corresponding location in a
sensor grid. In some embodiments, a control layer 120 may include
one or more gate drivers 122, which may be arranged to selectively
apply signals to toggle switches 124 between open and closed
states. In some embodiments, one or more of the switches 124 may be
thin film transistors (TFTs). Each electrode 110 may be connected
to a source line 121 of the control layer 120 by a respective via
126 which may lead to a terminal of a respective switch 124. Thus,
when the respective switch 124 is in a closed state (which may be
controlled by a gate driver 122), a signal received by the
electrode 110 may pass to the receiver 128. Conversely, when the
respective switch 124 is in an open state, the signal received by
the electrode may not pass to the receiver 128. In this manner,
electrodes or groups of electrodes (e.g., rows, columns, or other
groupings) may be sampled in respective timeslots, and the
resulting data may be accurately mapped to the location from which
the signals were received. Optionally, the received signals may
pass through a multiplexer 129 before they are passed to the
receiver 128.
[0039] In order to reduce parasitic coupling between the electrodes
110 and the source lines 121, an optional shield layer 130 may be
provided, in some embodiments, between the electrode layer and the
control layer 120. In some embodiments, the vias 126 may pass
through holes in the shield layer 130 so that signals from the
electrodes 110 may be passed to the control layer 120.
[0040] A sensor such as that illustrated in FIG. 1 may detect the
presence of an object (e.g., a user's finger or other element) by
measuring capacitance between a respective electrode 110 and the
object. There are a number of ways that this capacitance can be
measured. In some embodiments, a driving signal may be applied to
the object such that a voltage differential exists between the
object and the one or more electrodes that are sampled in a given
timeslot. In some embodiments, one or more dedicated structures
apply this driving signal, such as one or more dedicated driving
electrodes within the sensing area or a ring that partially or
fully surrounds the sensing area or grid of the sensing electrodes.
These dedicated structures, however, may negatively impact the
cost, size, and sensitivity of the sensor.
[0041] In preferred embodiments, one or more of the electrodes 110
may be used to provide a voltage differential between the object
and one or more electrodes 110 that will be sampled in a given
timeslot. In still other embodiments, a driving signal may be
applied to one or more electrodes immediately adjacent to an
electrode to be sampled in a given timeslot such that the presence
of an object in the vicinity of the sampled electrodes will
modulate the mutual capacitance between the sampled electrodes and
the adjacent electrodes to which the driving signal has been
applied. These and other techniques are described in detail
herein.
[0042] FIGS. 2A and 2B, 3, 4A, and 4B illustrate exemplary sensors
in which some or all of the electrodes have multiple states. In
some embodiments, the multiple states may include a first state in
which a driving signal is applied to the respective electrode and a
second state in which said driving signal is not applied to the
respective electrode. Additional states and sub-states may be
provided, as described in greater detail below. In some
embodiments, all of the electrodes within a sensing area of the
sensor may have multiple states. In other embodiments, only some of
the electrodes may have multiple states, while others may be
dedicated driving, dedicated sensing, or dedicated ground
electrodes.
[0043] In each of FIGS. 2A and 2B, 3, 4A, and 4B, electrodes shown
in white may be grounded in a respective timeslot, electrodes shown
in stripes may be in a sensing state in a respective timeslot, and
electrodes shown in black with white dots may be driven in a
respective timeslot. As reflected in these figures, the electrodes
of a sensor may be divided into logical groups, which may be in
sensing states, driven, or grounded together in any given timeslot.
Although these figures illustrate rows of electrodes being in
sensing states, driven, or grounded together, any other suitable
logical grouping scheme may be used. For example, columns may be
used in some embodiments. In other embodiments, electrodes may be
grouped into clusters, or the groups may be interleaved or
otherwise scattered across the sensor grid.
[0044] FIGS. 2A and 2B illustrate a sensor in which an exemplary
modulation technique is used to perform measurements using the
electrodes. FIG. 2A shows a first timeslot according to this
modulation technique, and FIG. 2B shows a second timeslot according
to this modulation technique. In some embodiments, the two
timeslots may be immediately adjacent to one-another (e.g., the
first timeslot may immediately precede or immediately follow the
second timeslot), though this is not required. For simplicity of
explanation, exemplary electrode sets 112a, 112b, 112c, 112d, and
112e are discussed, though other electrode sets (which may be
optionally single electrodes, lines of electrodes as illustrated in
FIGS. 2A and 2B, or other logical groupings of electrodes) may be
included in the modulation technique.
[0045] In the first timeslot, illustrated in FIG. 2A, a set of
electrodes 112b may be in a sensing state suitable for performing a
measurement. In this sensing state, the electrodes of set 112b may
be configured to perform a measurement while a driving signal is
applied. Application of this driving signal to the electrodes of
set 112b may create a voltage differential between these electrodes
and the object to be sensed, which may permit a measurable change
in capacitance depending upon the proximity of the object (e.g., a
ridge of a fingerprint may produce a different value than a
valley). In this manner, a measurement may be obtained without the
use of a dedicated drive ring or other dedicated drive electrodes.
In the first timeslot, illustrated in FIG. 2A, electrode sets 112a,
112c--which may be adjacent to the electrodes of set 112b--may
optionally be in a driven but non-sensing state. Providing driven
but non-detecting electrodes 112a, 112c immediately adjacent to the
driven and detecting electrodes 112b may reduce mutual capacitance
between the detecting electrodes of set 112b and one or more
grounded electrodes elsewhere on the sensor (e.g., electrode sets
112d, 112e and other electrodes shown in white in FIG. 2A). These
surrounding electrode sets (112a, 112c in this timeslot) may thus
act as guard lines, which may surround one or more electrodes that
are in a sensing state in a given timeslot and help to isolate the
signal of interest (here, capacitance between the sensing
electrodes and the object to be sensed). The remaining electrodes,
shown in white in FIG. 2A, may optionally be in a grounded state in
this timeslot. Grounding these electrodes may advantageously
conserve power, and it may also reduce the extent to which the
driving signal is transferred to the object to be sensed, which may
otherwise interfere with the sensor measurements.
[0046] In a second timeslot shown in FIG. 2B (which may immediately
precede, immediately follow, or be separated from the first
timeslot by one or more intervening timeslots) the electrode set
112d may be in the sensing state, such that the electrodes of set
112d may be configured to perform a measurement while a driving
signal is applied. Electrode sets 112c and 112e may be guard lines
which are in driven but non-sensing states. The remaining electrode
sets 112a, 112b, and other electrodes may optionally be in a
grounded state.
[0047] As will be understood by those of skill in the art,
additional sets of electrodes may be in sensing states (or grounded
or used as guard lines) in additional timeslots. In some
embodiments, electrode sets may be iterated timeslot-by-timeslot
until all desired electrodes have been placed in a sensing state.
In embodiments where electrode sets are logically grouped by lines,
the sensing sets may progress line-by-line across the sensor grid
timeslot-by-timeslot until all desired lines have been in a sensing
state.
[0048] FIG. 3 is a schematic diagram showing exemplary circuitry
for providing states such as those described above with respect to
FIGS. 2A and 2B. FIG. 3 depicts the same timeslot as shown in FIG.
2A, though the connections shown in FIG. 3 may be progressively
switched to other electrode sets to the sensing, guard, and
grounded states to be applied per the modulation technique
described above. (FIG. 6 depicts an exemplary switching arrangement
which may be used in combination with the circuitry of FIG. 3.) In
some embodiments, a driving signal may be applied by a power source
206. The power source 206 may be coupled, directly or indirectly,
to the electrodes of sets 112a and/or 112c. The power source 206
may also be coupled to a first terminal of an AFE 204. The
electrodes of the second set 112b, which may be in a driven-sensing
state in this timeslot, may be coupled to a second terminal of AFE
204. Circuit elements such as a capacitor and/or a reset switch may
be provided as a parallel connection between the electrodes of set
112b and the output 202 of AFE 204.
[0049] The AFE 204 may be configured to generate an output 202 such
that the voltage at the second terminal of the AFE 204 is
substantially equal to the voltage at the first terminal of the AFE
204. The magnitude of the output signal 202 necessary to achieve
this equivalence may vary based on the proximity of an object to be
sensed, which may form a capacitance to the electrodes of set 112b.
In this manner, the output 202 may vary depending on the proximity
of the object to be sensed. In subsequent timeslots, the first and
second terminals may be iteratively coupled to different sets of
electrodes, thereby allowing some or all of the electrodes of the
sensor grid to perform measurements.
[0050] FIGS. 4A and 4B illustrate a sensor in which another
exemplary modulation technique is used to perform measurements.
FIG. 4A shows a first timeslot according to this modulation
technique, and FIG. 4B shows a second timeslot according to this
modulation technique. In some embodiments, the two timeslots may be
immediately adjacent to one-another (e.g., the first timeslot may
immediately precede or immediately follow the second timeslot),
though this is not required. For simplicity of explanation,
exemplary electrode sets 114a, 114b, 114c, and 114d are discussed,
though other electrode sets (which may be optionally single
electrodes, lines of electrodes as illustrated in FIGS. 4A and 4B,
or other logical groupings of electrodes) may be included in the
modulation technique.
[0051] In the first timeslot, illustrated in FIG. 4A, a set of
electrodes 114b may be in a sensing state. In this sensing state,
the electrodes of set 114b may be floating, such that they are
receptive to a signal that may be received from (or modulated by)
an object to be sensed. The electrodes (including electrode set
114d) shown in black in FIG. 4A may be in a driving state, such
that a driving signal is applied to these electrodes during the
first timeslot. By applying a driving signal to these electrodes
(which may, in some embodiments, represent a majority of the
electrodes in the sensor), the object to be sensed may be coupled
to the driving signal. In this manner, a voltage differential may
be generated between the object and the electrodes of set 114b
which may be used to perform a measurement in this timeslot, and
the signals received from electrode set 114b may thus be indicative
of the presence or proximity of the object.
[0052] In the first timeslot, illustrated in FIG. 4A, electrode
sets 114a, 114c--which may be adjacent to the electrodes of set
114b--may optionally be in a grounded state. Providing grounded
electrodes immediately adjacent to the detecting electrodes 114b
may reduce mutual capacitance between the detecting electrodes of
set 114b and one or more driving electrodes elsewhere on the sensor
(e.g., electrode set 114d and other electrodes shown in white in
FIG. 2A). These surrounding electrode sets (114a, 114c in this
timeslot) may thus act as guard lines, which may surround one or
more electrodes that are in a sensing state in a given timeslot and
help to isolate the signal of interest (here, capacitance between
the detecting electrodes and the object to be sensed).
[0053] In other embodiments, the surrounding rows 114a, 114c may
instead be driven. In some embodiments, this may generate a mutual
capacitance between the detecting electrodes of set 114b and the
driving electrodes of sets 114a, 114c. When an object, such as a
user's finger, is proximate to one of the detecting electrodes,
this mutual capacitance may be modified. In this manner, the
electrodes of set 114b may thus receive both a self-capacitance and
a mutual-capacitance signal, both of which may be indicative of the
presence or proximity of the object.
[0054] In a second timeslot shown in FIG. 4B (which may immediately
precede, immediately follow, or be separated from the first
timeslot by one or more intervening timeslots) the electrode set
112c may be in the sensing state. In this sensing state, the
electrodes of set 114c may be floating, such that they are
receptive to a signal that may be received from (or modulated by)
an object to be sensed. The electrodes (including electrode set
114a) shown in black in FIG. 4B may be in a driving state, such
that a driving signal is applied to these electrodes during the
second timeslot. Electrode sets 114b and 114d may be optionally be
guard lines which are grounded to aid in isolating a
self-capacitance signal. Alternatively, the electrodes of sets 114b
and 114d may be driven to produce a mutual-capacitance signal which
may be indicative of the presence or proximity of the object.
[0055] As will be understood by those of skill in the art,
additional sets of electrodes may be in sensing states (or grounded
or used as guard lines) in additional timeslots. In some
embodiments, electrode sets may be iterated timeslot-by-timeslot
until measurements have been collected from all desired electrodes.
In embodiments where electrode sets are logically grouped by lines,
the sensing sets may progress line-by-line across the sensor grid
timeslot-by-timeslot until all desired lines have been placed in a
sensing state.
[0056] FIG. 5 shows a schematic for an exemplary multi-state
electrode 110. A multi-state electrode such as that shown in FIG. 5
may be used in any appropriate modulation technique, including, but
not limited to that described above with reference to FIGS. 4A and
4B. In the illustrated embodiment, the electrode 110 may have four
states, each of which may be selectively controlled by switches
332a, 332b, 332c, 332d. When switch 332a is closed, the electrode
may be electrically connected to a shield 140. In some embodiments,
the shield 140 may help to isolate the electrode 110 from output
lines 314a, 314b. In some embodiments, the shield 140 may be
coplanar to one, some, or each of the electrodes 110 and the output
lines 314a, 314b. In some embodiments, the shield 140 may be
grounded. In other embodiments, as discussed in greater detail
below (including, but not limited to, with respect to FIGS. 8-11),
the shield 140 may be selectively driven or selectively grounded,
such that closing switch 332a may selectively cause the electrode
110 to be driven or grounded. When switch 332d is closed, the
electrode may be electrically connected to a driving signal applied
by a power source 320. In embodiments where the shield may be
selectively driven by a power source, switch 332d may optionally be
omitted.
[0057] When switch 332b is closed, the electrode 110 may be
electrically connected to a first output line 314a. When switch
332c is closed, the electrode 110 may be electrically connected to
a second output line 314b. As discussed below with reference to
FIGS. 6 and 7, the output lines 314a, 314b may be selectively
connected to an array of electrodes, for example, along a given row
or column of a sensor grid. When the switches 312 corresponding to
the output lines 314a, 314b are closed, output line 314a may be
connected to a first receive line 316a, and output line 314b may be
connected to a second receive line 316b. The two receive lines
316a, 316b may be connected to respective terminals of an AFE 310.
For example, receive line 316a may be connected to a positive
terminal of AFE 310, and receive line 316b may be connected to a
negative terminal of AFE 310. In some embodiments, the AFE 310 may
be a differential receiver. In some embodiments, an output from the
AFE 310 may indicate a difference between the signals received from
output lines 316a and 316b.
[0058] In some embodiments, output line 314a may act as a positive
output line, while output line 314b may act as a negative output
line. This may allow a measurement signal received by electrode 110
to be selectively routed into either a positive terminal or a
negative terminal of AFE 310, depending on which of switches 332b,
332c is closed. In the illustrated embodiment, for example, when
switch 332b and switch 312 are closed, a signal received by
electrode 110 may be transmitted to a positive terminal of AFE 310
(in this case, the electrode 110 may be in a positive sensing
state). When switch 332c is closed, a signal received by electrode
110 may be transmitted to a negative terminal of AFE 310 (in this
case, the electrode 110 may be in a negative sensing state). The
switches 332a, 332b, 332c, 332d may be controlled by one or more
gate drivers 330, which may apply signals to the switches by way of
gate lines 331a, 331b, 331c, 331d. In some embodiments, a gate
driver 330 may selectively close only one of switches 332a, 332b,
332c, 332d in any given time slot. In some embodiments, the
switches 332a, 332b, 332c, 332d may be selectively closed in a
sequence determined by a modulation pattern, which may include, for
example, a code division multiplexing (CDM) pattern.
[0059] Although the multi-state electrode 110 of FIG. 5 is shown
with four switches corresponding to four states, different numbers
of switches or states may be provided. As one example, a single
switch could be used to ground, drive, and/or place the electrode
in a sensing state, depending on the signal provided along that
path. Likewise, in some modulation techniques, it may be
unnecessary to ground electrodes, or it may be unnecessary to have
multiple sensing states (e.g., a single sensing state may be used
instead of positive and negative sensing states). As one example,
it may be unnecessary to ground electrodes according to a variant
of the modulation technique illustrated in FIGS. 4A and 4B where no
guard lines are used, and in this variant, a ground state may
optionally be omitted. It is thus permissible to use any
combination of the switches and states illustrated in FIG. 5 to
suit the needs of any given application.
[0060] FIG. 6 shows an exemplary schematic of a sensor having a
grid of multi-state electrodes. The multi-state electrodes in FIG.
6 are shown with four states and four switches as described above
with reference to FIG. 5. Specifically, each of electrodes
110a-110i may have a ground state, a driving state, a positive
sensing state, and a negative sensing state. As discussed above,
any of these states may be omitted or modified depending on the
needs of any given application.
[0061] As illustrated in FIG. 6, each of electrodes 110a-110c,
which may be aligned in a first column, may be selectively
connected to either of first column output lines 314a, 314b. The
first column output lines 314a, 314b may be selectively connected
to receive lines 316a, 316b by way of first column switches 312a.
The two receive lines 316a, 316b may be connected to respective
terminals of an AFE 310. For example, receive line 316a may be
connected to a positive terminal of AFE 310, and receive line 316b
may be connected to a negative terminal of AFE 310. Each of
electrodes 110d-110f, which may be aligned in a second column, may
be selectively connected to either of second column output lines
314c, 314d. The second column output lines 314c, 314d may be
selectively connected to receive lines 316a, 316b by way of second
column switches 312b. Third column electrodes 110g-110i may
similarly be connected to receive lines 316a, 316b via switches
312c. Additional rows and columns may be added in the same manner
as needed to achieve a desired sensor size or resolution.
[0062] By arranging the electrodes in this manner, any given
electrode in the grid may be selectively toggled into a positive
sensing state or a negative sensing state. Specifically, the column
or columns of electrodes from which signals are received in a given
timeslot may be controlled by way of switches 312a, 312b, 312c.
Meanwhile, rows of electrodes may be selectively coupled to
respective output lines 314 in response to control signals from a
gate driver 330a. For example, when a signal is applied to gate
line 331a, each of the electrodes 110a, 110d, 110g in a first row
may be connected to a respective positive output line 314a, 314b,
314c. Similarly, when a signal is applied to gate line 331b, each
of the electrodes 110a, 110d, 110g in the first row may be
connected to a respective negative output line 314b, 314d, 314f. In
either case, the system may control which of the first row
electrodes 110a, 110d, 110g is to be in a sensing state in a given
timeslot by controlling switches 312a, 312b, 312c. This approach
may be used to selectively perform measurements in a positive or
negative state from any of electrodes 110a-110i.
[0063] In some embodiments, a second gate driver 330b may be used
to selectively control ground and/or driving states. In some
embodiments, gate driver 330b may selectively control ground and/or
driving states on a column-by-column basis. For example, when
switch 334a is closed, each of the electrodes 110a, 110b, 110c in
the first column may be connected to a power source 320, which may
apply a driving signal. Likewise, when switch 334c or switch 334e
is closed, the electrodes in the second column or third column may
be respectively coupled to the power source, which may apply a
driving signal to these electrodes. When switch 334b is closed,
each of the electrodes 110a-110c in the first column may be
connected to a respective shield 140, which may, in some
embodiments, be grounded. Likewise, when switches 334d or 334f is
closed, the electrodes in the second column or third column may be
respectively coupled to a shield and/or grounded.
[0064] FIG. 7 shows another exemplary schematic of a sensor having
a grid of multi-state electrodes. The arrangement shown in FIG. 7
is similar to that illustrated in FIG. 6, and the description above
likewise applies to FIG. 7. As illustrated in FIG. 7, however,
shields 140 in a given column may optionally be electrically
connected by abutments 141. A first column of shields 140 may be
selectively connected by one or more switches 335a to either of
power source 320 (which may apply a driving signal) or ground. In
this manner, the first column of shields may be used to selectively
ground or drive the electrodes 110a-110c of the first column. For
example, when switch 334b is closed, each of the electrodes
110a-110c may be electrically connected to their respective
shields. By using switch 335a to connect the shields of that column
to power source 320, each of electrodes 110a-110c may be driven.
Likewise, by using switch 335a to connect the shields of that
column to ground, each of electrodes 110a-110c may be grounded.
Switches 334d and 335b may be used to selectively ground or drive
the electrodes 110d-110f of the second column, and switches 334f
and 335c may be used to selectively ground or drive the electrodes
110-g-110i of the third column in the same manner. The same
approach may be used to ground or drive as many columns as may be
desired in any given application.
[0065] Arrangements such as those illustrated in FIGS. 6 and 7
advantageously allows a sensor grid to include any desired number
of electrodes without increasing the fraction of the sensor area
that must be dedicated to source lines extending between an AFE and
the electrodes. This is a significant problem in self-capacitance
sensors in which every electrode has a respective source line,
since as the number of electrodes in a given row or column
increases, an increasingly large number of source lines be run
parallel to one-another, occupying an increasingly greater fraction
of the available area. By contrast, FIGS. 6 and 7 shows embodiments
where any number of electrodes in a given column can be connected
to two shared output lines (e.g., all of the electrodes in a first
column may be selectively connected output liens 314a, 314b). The
density of column and gate lines likewise does not need to increase
as the sensor area grows larger.
[0066] In some embodiments, a multiplexing pattern may be applied
to perform measurements using the electrodes of the sensor grid. In
some embodiments, for example, CDM pattern may be applied to
collect data from a given column or row of the sensor grid. In some
embodiments, the multiplexing patterns may include Hadamard,
Legendre, Barker sequences, modifications of these sequences, or
other suitable CDM matrices. In some embodiments, the multiplexing
patterns may be "balanced" such that for each of the timeslots in
the respective pattern, an array of modulation factors
corresponding to the respective timeslot (e.g., the values in a
given column) may sum to substantially zero. For purposes of
illustration, an exemplary balanced 4.sup.th-order
pseudo-orthogonal pattern is reproduced below:
+1 -1 -1 0 -1 -1 +1 0 -1 +1 -1 0 +1 +1 +1 0
[0067] In the above exemplary pattern, the values in each column
sum to zero. Additionally, because the values in the right-most
column are all 0's, the signals that are applied or received in
this timeslot may convey no information and may optionally not be
acquired and/or processed. Of course, other suitable patterns may
be selected, as will be understood by those of skill in the
art.
[0068] In some embodiments, a CDM pattern may be applied to perform
measurements using the electrodes of a given column. For example,
each column of a CDM pattern may represent a given timeslot, and
each row of the CDM pattern may represent a modulation factor to be
applied to a respective electrode in that timeslot. A modulation
factor of +1 may indicate that the respective electrode should be
in a positive sensing state. A modulation factor of -1 may indicate
that the respective electrode should be in a negative sensing
state. A modulation factor of 0 may indicate that the respective
electrode should be in a non-sensing state (e.g., not connected to
an output line and/or not connected to a receive line). For
example, applying the top row of the exemplary CDM pattern above to
electrode 110a in FIG. 6 would indicate that: in a first timeslot,
electrode 110a should be connected to positive output line 314a; in
a second timeslot, electrode 110a should be connected to negative
output line 314b; in a third timeslot, electrode 110a should be
connected to negative output line 314b; and in a fourth timeslot,
electrode 110a should not be connected to either output line (or
the data should otherwise not be collected).
[0069] Any suitable multiplexing pattern of any suitable order may
be used. For example, the multiplexing patterns and
sensing/processing techniques described in U.S. patent application
Ser. Nos. 15/869,214 and 16/108,875 may be used to perform
measurements using electrodes in the sensors illustrated herein,
including the embodiments illustrated in FIGS. 6 and 7. In some
embodiments, the grouping techniques disclosed in U.S. patent
application Ser. Nos. 15/869,214 and 16/108,875 may be applied to
the electrodes of sensors such as those illustrated in FIGS. 6 and
7 on a column-by-column basis. In some embodiments, using balanced
multiplexing patterns may cause a common mode portion of the
resulting signal to be canceled. This may beneficially remove a
carrier signal or body-coupled noise from the signal, thereby
allowing a greater fraction of the dynamic range of the processing
circuitry to be allocated to the measurement signal.
[0070] FIGS. 8-11 show exemplary embodiments of multi-state
electrodes. FIG. 8A is a plan-view looking down on an exemplary
multi-state electrode 110. FIG. 8B shows a cross-sectional view of
the same electrode 110 taken at line 8B-8B. A perimeter of the
electrode 110 may be surrounded, in whole or in part, by a shield
140a. A surface of the electrode 110 may be unshielded (i.e., in a
Z-direction in FIG. 8A and an upward direction in FIG. 8B) such
that the electrode 110 may be sensitive to electric field changes
caused by the presence of an object to be detected (e.g., a user's
finger). In some embodiments, the shield 140 may be comprised of
conductive metal. In some embodiments, the shield 140 may be
co-planar with one or both of the electrode and an output line 314.
For purposes of this disclosure, two structures may be considered
to be "co-planar" with one-another if they are deposited in a
common layer during manufacture. Co-planar structures need not be
precisely parallel to one-another, and indeed, they often will not
be precisely parallel to one-another due to manufacturing
variances. In some embodiments, the electrode 110 may be
selectively connectable with the output line 314 by a switch 332a.
In some embodiments, the switch 332a may be controlled by a gate
line 331a. In some embodiments, the electrode may be selectively
connectable with the shield 140 by a switch 332b.
[0071] FIG. 8B illustrates an exemplary cross-section diagram of
the embodiment of FIG. 8A. In some embodiments, electrode 110 may
be surrounded on either side by a shield 140a. The electrode may be
connected to an output line 314 by way of a switch 332a, which may,
in some embodiments, be a transistor 332a. In some embodiments,
vias 145a, 145b may be used to connect electrode 110 and output
line 314 to switch 332a. In some embodiments, a second switch 332b
(shown in FIG. 8A, not shown in FIG. 8B) may selectively connect
the electrode 110 to the shield 140a. In some embodiments, the
shield 140a may be coplanar to one or both of the electrode 110 and
the output line 314. In some embodiments, a shield 140d may be
provided on the other side of the output line 314, thereby
providing shielding between the output line 314 and an electrode in
an adjacent cell (adjacent electrode not shown). In some
embodiments, shield 140d may be a co-planar shield (similar to
shield 140a) that surrounds or partially surrounds a neighboring
electrode. In some embodiments, supplemental shields 142a, 142b,
144a, 144b, 146 may be provided to shield electric field lines that
may otherwise extend above or below the coplanar shields 140a,
140d. In some embodiments, one or more of the supplemental shields
142a, 142b, 144a, 144b, 146 may be electrically connected to
shields 140. In some embodiments, one, some, or all of supplemental
shields 142a, 142b, 144a, 144b, 146 may extend linearly alongside
respectively electrode columns. In some embodiments, these shields
may be disposed to leave an unobstructed electric field path
between electrode 110 and an object to be sensed. Each of these
shields is optional, and each may be included or omitted on an
individual basis depending on the objectives in a given system. For
example, depending on the proximity of the electrodes and output
lines and the magnitude of the signals, the extent to which
undesired coupling occurs may increase or decrease, thereby
increasing or decreasing the extent to which additional shield
layers are beneficial and cost-effective. In FIG. 8A, shields 140d,
142a, 142b, 144a, 144b, 146 are not shown to simplify the
illustration. These shields may be provided, however, and they may
be preferably disposed at the locations indicated by FIG. 8B (e.g.,
between adjacent electrodes 110, and between electrodes 110 and
output lines 314).
[0072] The lines in FIG. 8B reflect layers that may be deposited in
sequence from the bottom up. That is, the switch 332 may be
deposited on a base layer, an interim layer may then be deposited,
then shield 146 may be deposited, then another interim layer, then
shields 144a and 144b, and so on. Notably, the electrodes 110,
shields 140, and output lines 314 may thus be deposited in a single
layer using a single manufacturing step. This may advantageously
reduce manufacturing cost. Additionally, in embodiments where
optional shields 142, 144, 146 are omitted, the manufacturing
process may be greatly simplified by making the shield 140 coplanar
to the electrodes 110 and output lines 314. In such embodiments, a
deposition step may be used to create switches 332 (and/or any
associated drive lines), an interim layer may then be deposited,
and then the electrodes 110, shields 140, and output lines 314 may
be deposited in a single step. This may advantageously permit a
simplified sensor stack-up with two metal layers (e.g., a control
layer and an electrode/output layer), as compared to the stack-up
with three metal layers shown in FIG. 1 (e.g., a control and output
layer, an electrode layer, and a shield layer therebetween).
[0073] FIG. 9 illustrates another exemplary arrangement for a
system having multi-state electrodes. The embodiment illustrated in
FIG. 9 is similar to the embodiments shown in FIGS. 8A-8B, and the
corresponding description above likewise applies to FIG. 9. Similar
to the embodiments shown in FIGS. 8A-8B, electrodes 110a, 110b (or
any number of electrodes, see FIGS. 6-7 for exemplary layouts which
may be expanded to include any desired number of electrodes) may be
connected to an output line 314 by way of respective switches. In
some embodiments, the switches may be controlled by respective gate
lines. In some embodiments, electrode 110a, 110b may also be
selectively connectable with shields 140a, 140b by respective
switches, which may be controlled by respective gate lines. In some
embodiments, the shields 140a, 140b may be coplanar to one or both
of the electrode 110 and the output line 314.
[0074] As illustrated in FIG. 9, shields 140a, 140b, which may
correspond to adjacent electrodes 110a, 110b, are electrically
connected to one another. In some embodiments, shields 140a, 140b
may be connected by an abutment 141, which may join one section of
shield 140a to shield 140b. In some embodiments, the shields 140a,
140b may be include a shared portion, or they may be connected by
wiring. In some embodiments, some or all of the shields in a row or
column may be electrically connected to one-another. For example,
FIG. 7 shows an embodiment in which the shields in respective lines
of a sensor grid are electrically connected to one another such
that a driving signal and/or ground voltage may be applied to the
electrodes in the respective lines. The structural arrangement
shown in FIG. 9 is one option for achieving this advantageous
arrangement.
[0075] FIG. 10 illustrates another exemplary arrangement for a
system having multi-state electrodes. The embodiment illustrated in
FIG. 10 is similar to the embodiments shown in FIGS. 8A-8B and 9,
and the corresponding description above likewise applies to FIG.
10. Similar to the embodiments shown in FIGS. 8A-8B and 9,
electrodes 110a, 110b (or any number of electrodes, see FIGS. 6-7
for exemplary layouts which may be expanded to include any desired
number of electrodes) may be connected to an output line 314 by way
of respective switches. In some embodiments, the switches may be
controlled by respective gate lines. In some embodiments, electrode
110a, 110b may also be selectively connectable with shields 140a,
140b by respective switches, which may be controlled by respective
gate lines. In some embodiments, the shields 140a, 140b may be
coplanar to one or both of the electrode 110 and the output line
314.
[0076] As illustrated in FIG. 10, shields 140a, 140b may be
electrically connected to respective lines 321a, 321b. In some
embodiments, the lines 321a, 321b may be drive lines which may
selectively supply a driving signal to the respective shields 140a,
140b. In some embodiments, the lines 321a, 321b may selectively
apply a ground voltage. In some embodiments, the lines 321a, 321b
may be controlled by a gate driver, such as gate driver 330b as
illustrated in FIGS. 6 and 7. In some embodiments, the arrangement
shown in FIG. 10 may allow driving and/or ground signals to be
selectively applied to linear arrays of electrodes. For example,
some or all of the electrodes along a row or column of electrodes
may be connected to line 321a, such that all of the electrodes in
this row or column may be selectively driven or grounded together.
In some embodiments, lines 321a, 321b may extend transversely to
output lines 314, such that driving and/or ground signals may be
selectively applied along line(s) extending transversely to the
line(s) of electrodes from which measurement signals are
selectively received.
[0077] FIGS. 11A-11B illustrate another exemplary arrangement for a
system having multi-state electrodes. The embodiment illustrated in
FIGS. 11A-11B is similar to the embodiments shown in FIGS. 8A-8B,
9, and 10, and the corresponding description above likewise applies
to FIG. 11. Similar to the embodiments shown in FIGS. 8A-8B, 9, and
10, electrodes 110a, 110b may be connected to an output line 314 by
way of respective switches. In some embodiments, the switches may
be controlled by respective gate lines. In some embodiments,
electrode 110a, 110b may also be selectively connectable with
shields 140a, 140b by respective switches, which may be controlled
by respective gate lines. In some embodiments, the shields 140a,
140b may be coplanar to one or both of the electrode 110 and the
output line 314.
[0078] Like the embodiment illustrated in FIG. 10, the embodiment
of FIG. 11A-11B includes lines 321a, 321b, which may be used to
selectively apply a driving signal or ground voltage to electrodes
110a, 110b. Rather than connecting to shields 140a, 140b, however,
lines 321a, 321b may connect to segments 350, which may be
selectively connected to electrodes 110a, 110b via respective
switches 332b. In this manner, a driving signal may be selectively
applied to electrodes 110a, 110b without also applying the driving
signal to the associated shields. Segments 350 may optionally be
coplanar to the electrodes. Alternatively, lines 321a, 321b and
associated switches 332b may be provided in one or more layers
below the electrodes 110a, 110b. In the latter case, driving
signal(s) may be connected to the electrodes by vias, which may
directly connect to the electrodes 110a, 110b, or may alternatively
connect to one or more intermediate structures such as segments
350. Optionally, shields in a common column and/or row may be
electrically connected to one-another, which may facilitate
grounding the shields. In some embodiments, shields in both columns
and rows may be electrically connected to one-another, such that
some or all of the shields 140 may be grounded together.
[0079] As discussed above with respect to FIG. 10, lines 321a, 321b
may extend transversely to output lines 314. In some embodiments,
as shown in FIGS. 11A and 11B, a shield 148 may be disposed
vertically between the output line 314 and lines 321a, 321b.
[0080] FIG. 11B shows an exemplary cross-section taken at a
position indicated by arrows 11B in FIG. 11A. In some embodiments,
a first output line 314a may extend adjacent to a respective
segment 350, which may be connected to line 321a by a via 145c.
Shield 140a may extend between segment 350 and a second output line
314b, which may be associated with an adjacent cell (or column or
row). In some embodiments, a shield 148a may be provided between
line 321a and output line 314a. Likewise, a shield 148b may be
provided between line 321a and output line 314b. In some
embodiments, optional shields 148a, 148b may reduce coupling
between a driving signal applied by line 321a and the signals
received by output lines 314a, 314b.
[0081] FIG. 12 illustrates a figurative diagram of an exemplary
sensor system 400. The sensor system 400 may include a memory 410,
a processor 420, a transducer 430, and a power source 440 and
circuitry to connect them. In some embodiments, the transducer 430
may be embodied as a two-dimensional grid of electrodes and
receiving circuitry as described above. The memory 410 may store
instructions for or results of any of the processing steps,
calculations, and/or determinations described herein. The processor
420 may be configured to perform any of these processing steps,
calculations, and/or determinations. In some embodiments, the power
source 440 may be a battery, capacitor, inductor, generator, or
other element capable of applying power. Components 410, 420, 430
and 440 need not exist within a single physical device. For example
the memory 410 and/or the processor 420 may be distributed among
multiple devices and/or they may be connected (e.g., by wired or
wireless connections) to other components of the sensor system
400.
[0082] FIG. 13 illustrates an exemplary method 500 for performing
measurements using a sensor system with multi-state electrodes. In
some embodiments, the system may include a plurality of electrodes,
and each electrode of the plurality of electrodes may have at least
a first state in which a driving signal is applied to the
respective electrode and a second state in which a driving signal
is not applied to the respective electrode. In some embodiments,
any of the multi-state electrode arrangements described above may
be used. Method 500 may be performed using electrodes having
exactly two states, or it may be performed using electrodes having
more than two states. For example, multiple driving states may be
used (e.g., driven sensing states, and driven non-sensing states).
Likewise, multiple non-driving states may be used (e.g., sensing
states and grounded states). Unless otherwise specified, references
to states should be broadly understood to refer to any appropriate
state or states that satisfy the description(s) associated with
that respective state.
[0083] In some embodiments, steps 502, 504, 506 may be performed in
a first timeslot. The first timeslot may include one or more
subparts. For example, the first timeslot may be divided into
multiple subparts such that a set of electrodes may be in a sensing
state according to a CDM pattern within the first timeslot. In step
502, a first set of electrodes may be in a first state such that a
driving signal is applied to the first set of electrodes. In some
embodiments, applying the driving signal to the first set of
electrodes may generate, at least in part, a difference in voltage
between the body portion and a first set of detecting electrodes.
In step 504, a second set of electrodes may be in a second state
such that the second set of electrodes are not driven. In step 506,
the first set of detecting electrodes may be placed in a sensing
state to collect a first set of measurements, which may indicate
whether a body portion or a component thereof is within a
detectable range of the first set of detecting electrodes. In some
embodiments, the first set of detecting electrodes may be identical
to the first set of electrodes such that the first set of
electrodes may be used to perform measurements at the same as they
are driven. (Exemplary embodiments are described above with respect
to FIGS. 2A, 2B and 3). In other embodiments, the first set of
detecting electrodes may be identical to the second set of
electrodes such that the second set of electrodes may be used to
perform measurements while they are not driven. (Exemplary
embodiments are described above with respect to FIG. 4).
[0084] In some embodiments, steps 508, 510, 512 may be performed in
a second timeslot. The second timeslot (and any subsequent
timeslots) may also include one or more subparts. For example, the
second timeslot may be divided into multiple subparts such that a
set of electrodes may be placed in sensing states according to a
CDM pattern within the second timeslot. In step 508, the second set
of electrodes may be in the first state such that the driving
signal is applied to the second set of electrodes. In some
embodiments, applying the driving signal to the second set of
electrodes may generate, at least in part, a difference in voltage
between the body portion and the second set of detecting
electrodes. In step 510, the first set of electrodes may be in the
second state such that the first set of electrodes are not driven.
In step 512, the second set of detecting electrodes may be placed
in a sensing state to collect a second set of measurements, which
may indicate whether a body portion or a component thereof is
within a detectable range of the second set of detecting
electrodes. In some embodiments, the second set of detecting
electrodes may be identical to the second set of electrodes such
that the second set of electrodes are used to perform a measurement
at the same as they are driven. (One such example is described
above with respect to FIGS. 2A, 2B and 3). In other embodiments,
the second set of detecting electrodes may be identical to the
first set of electrodes such that the first set of electrodes are
used to perform a measurement while they are not driven. (One such
example is described above with respect to FIG. 4). As will be
apparent from the foregoing description, method 500 may be repeated
as many times as needed to collect measurements from all desired
electrodes of a sensor system.
[0085] In some embodiments, a driving signal may be applied to a
third set of electrodes during the first timeslot. For example,
driving signals may be applied to a guard lines of electrodes, as
illustrated in FIGS. 2A, 2B and 3. In some embodiments, including
but not limited to that illustrated in FIG. 3, at least one
electrode of the first set of electrodes may be connected to a
first terminal of an analog front end, and at least one electrode
of the third set of electrodes may be connected to a second
terminal of the analog front end. For example, an electrode of the
first set may be connected to the first terminal of the AFE such
that it is in a driven sensing state, and an electrode of the third
set may be connected to the second terminal of the AFE such that it
is in a driven non-sensing state.
[0086] In some embodiments, a third set of electrodes, which may be
adjacent to the first set of electrodes, may be in a grounded state
in the first timeslot. In some embodiments, the grounded third set
of electrodes may be adjacent to the first set of detecting
electrodes. In some embodiments, the grounded electrodes may act as
a guard line during the first timeslot. In some embodiments, the
third set of electrodes in the grounded state may be electrically
connected to a shield that is coplanar with the plurality of
electrodes.
[0087] In some embodiments, the first set of electrodes may be
adjacent to the second set of electrodes. In some embodiments,
during the first timeslot, the first set of electrodes may be
driven, and the second set of electrodes may be in a non-driven
sensing state, such that a mutual capacitance is formed between the
electrodes of the first set and the electrodes of the second set.
In some embodiments, the first set of measurements received by the
second set of electrodes during the first timeslot may indicate
that the body portion modified a mutual capacitance between an
electrode of the first set of electrodes and an electrode of the
second set of electrodes.
[0088] In some embodiments, the first and/or second timeslots may
include multiple subparts. In some embodiments, the multiple
subparts may be used to collect measurements from electrodes using
CDM patterns, as described above. In some embodiments, the second
state, which may be a sensing state, may include multiple
sub-states. For example, the second state may include a first
detecting state (e.g., a positive sensing state) in which a
respective electrode of the plurality of electrodes is connected to
a first terminal of an AFE. The second state may also include a
second detecting state (e.g., a negative sensing state) wherein the
respective electrode is connected to a second terminal of an AFE.
In some embodiments, a first electrode of the second set of
electrodes may be in the first detecting state during a first
subpart of the first timeslot. In some embodiments, a second
electrode of the second set of electrodes may be in the second
detecting state during the first subpart of the first timeslot. In
embodiments where the AFE determines a difference between the
signals received from the first and second terminals, the AFE may
thereby determine, at least in part, a difference in the signals
received from the first and second electrodes during the first
subpart of the first timeslot. In subsequent subparts of the
timeslots, measurements may be collected from the electrodes of the
second set (including, e.g., the first and second electrodes) using
the first and second detecting states. In some embodiments, the
selection of detecting states in the respective subparts of the
timeslots may determined according to a CDM pattern.
[0089] FIG. 14 illustrates another exemplary embodiment for a
sensor. In this embodiment, a sensor may include a plurality of
cells 10, each of which may be configured to be used to perform a
presence measurement. In some embodiments, each cell 10 may include
a transmit electrode (e.g., 12a-f) and a receive electrode (e.g.,
11a-f). In some embodiments, the cells 10 may be arranged in linear
arrays 20a, 20b, 20c. For example, a first linear array 20a may
include cell 11a, 12a, cell 11b, 12b, and cell 11ac, 12c. A second
linear array 20b may likewise include its own cells (shown in FIG.
14), a third linear array 20c may include cell 11d, 12d, cell 11e,
12e, and cell 11f, 12f. Each of the transmit electrodes (e.g.,
12a-12c) in a respective linear array (e.g., 20a) may be
selectively connected to associated drive lines (e.g., 16a, 17a)
for that linear array (e.g., 20a). Likewise, each of the receive
electrodes (e.g., 11a-11c) in a respective linear array (e.g., 20a)
may be connected to an associated output line (e.g., 14a) for that
linear array (e.g., 20a). This arrangement may be applied across a
sensor area for as many linear arrays as are desired for a given
application. Likewise, each linear array in a sensor area may
include as many cells as are desired for a given application.
[0090] In some embodiments, a transmit electrode 12a may be
configured to apply one or more driving signals, such that a
capacitive signal received by a receive electrode 11 a in the same
cell 10 may be modulated if an object to be sensed is within a
detectable range. FIG. 14 shows an exemplary embodiment in which
each transmit electrode 12a-12f is configured to selectively apply
two driving signals (one at a time). For example, transmit
electrode 12a may have a first state in which it is selectively
connected to drive line 16a, which in turn may be selectively
connected to a first central drive line on which a first driving
signal TX_P may be applied. Transmit electrode 12a may have a
second state in which it is selectively connected to drive line
17a, which in turn may be selectively connected to a second central
drive line on which a second driving signal TX_N may be applied. In
some embodiments, the first and second driving signals may be
inverted relative to one another. In some embodiments, the first
and second driving signals may sum to substantially zero. As shown
in FIG. 14, each of the transmit electrodes 12a-12f in the sensor
system may likewise have first and second states, which may be
selectively applied by connecting the respective transmit electrode
to one of two or more respective drive lines, through which first
and second driving signals may be applied.
[0091] In some embodiments, a selection between the first and
second states may be effected via gate lines (e.g., 18, 19). For
example, when gate line 18 is active, transmit electrode 12a may be
connected to drive line 16a, such that transmit electrode 12a is in
the first state. Conversely, when gate line 19 is active, transmit
electrode 12a may be connected to drive line 17a, such that
transmit electrode 12a is in the second state. In some embodiments,
each electrode in a row (e.g., a group of electrodes extending in a
direction transversely to a linear arrays 20a, 20b, 20c) may be
controlled via common gate lines. For example, transmit electrode
12a and transmit electrode 12d may both be controlled by gate lines
18, 19. In this manner, during a timeslot in which transmit
electrode 12d is in the first state, transmit electrode 12d may
also be in the first state (assuming that arrays 20a and 20c are
active in the same timeslot). The same principle may extend to each
of the rows of the system.
[0092] In some embodiments, drive lines 16a, 17a may also be
selectively connected to a central ground line GND, which may cause
drive lines 16a, 17a to be grounded. In some embodiments, drive
lines may be selectively connected to either driving signals TX_P,
TX_N or to ground GND. In some embodiments, this selection may be
performed on an array-by-array basis. For example, in a given
timeslot, the drive lines for array 20a may be driven, the drive
lines for array 20b may be grounded, and the drive lines for array
20c may be driven. Any desired permutation of driven and grounded
arrays may be used. In some embodiments, it may be preferable to
avoid having adjacent arrays driven simultaneously, in order to
reduce parasitic capacitance between the arrays. For example, array
20a may be driven (and measurements obtain from the cells of array
20a) while adjacent array 20b (arrays 20a and 20b are considered to
be adjacent arrays because there are no other arrays between arrays
20a and 20b) is grounded. In a subsequent timeslot, array 20a may
be grounded while adjacent array 20b is driven.
[0093] In some embodiments, the arrays may be configured such that
the output lines (e.g., 14a, 14b) may be selectively connected to a
central receive line 22, which may be connected to an AFE. In some
embodiments, an array's receive line may be connected to an AFE
while that array's drive lines are driven. Conversely, when the
array's drive lines are grounded, that array's receive line may be
disconnected to the AFE. For example, selection circuitry may be
used to activate the cells of array 20a in a given timeslot (or
group of timeslots). While array 20a is active, drive lines 16a,
17a may be connected to respective central driving lines to apply
first and second driving signals TX_P, TX_N. At the same time,
output line 14a may be connected to central receive line 22, such
that measurements received by the cells of array 20a may be
transmitted to an AFE. Conversely, while array 20a is inactive,
drive lines 16a, 17a may be connected to a ground line GND, and
output line 14a may be disconnected from central receive line 22.
This same operative configuration may be extended to each of the
arrays in a sensor. In this manner, selection circuitry may be used
to select which arrays are active and inactive in a given timeslot,
so that the signals received by the AFE in each timeslot may be
correlated with a correct array and cell. Likewise, by controlling
which arrays are grounded, parasitic capacitance may be reduced
(e.g., by interleaving active and inactive arrays).
[0094] In some embodiments, an AFE may receive measurement signals
from some or all of the cells 10 in an array (e.g., 20a)
simultaneously. In some embodiments, a CDM pattern may be applied
to the cells 10 of an array (e.g., 20a) such that the measurement
signals received by the AFE may be correlated with a correct cell
in that array. As one example, a Legendre code may be modified to
have two states (e.g., a +1 and a -1 state), and that code may be
applied to the transmit electrodes (e.g., 12a, 12b, 12c) of an
array by driving the transmit electrodes using the first driving
signal and the second driving signal according to the states
indicated by the code. Other suitable multiplexing may also be
used. In embodiments where cells have only two states, CDM patterns
with only two states may be used. In some embodiments, cells may be
provided with a third state (e.g., a ground state). For example,
transmit electrodes may optionally be configured to connect to a
third drive line (or shield) that is always grounded. In such
embodiments, CDM patterns with three states (e.g., +1, 0, -1) may
be used.
[0095] For example, in a first timeslot, the first driving signal
may be applied to transmit electrode 12a, and a measurement signal
may be received using receive electrode 11a. At the same time, the
second driving signal may be applied to transmit electrode 12b, and
a measurement signal may be received using receive electrode 11b.
In a second timeslot, the second driving signal may be applied to
transmit electrode 12a, and a measurement signal may be received
using receive electrode 11a. At the same time, the first driving
signal may be applied to transmit electrode 12b, and a measurement
signal may be received using electrode 11b. The driving signals
applied over a plurality of timeslots in a given array (e.g., 20a)
may thus be selected according to a multiplexing pattern, such that
a plurality of measurement signals received by an output line
(e.g., 14a) may be decoded and the received measurement signals
correlated to the correct cells. In some embodiments, the system
may then select another linear array, and repeat this process to
obtain measurements from the cells of that linear array. In some
embodiments, the process may be repeated for each linear array
until at least one measurement has been obtained from each cell in
a sensing area of the system.
[0096] In some embodiments, measurements may be collected from the
cells of multiple arrays simultaneously. For example, in the
exemplary embodiment of FIG. 14, measurements may be collected from
arrays 20a and 20c simultaneously. This may be accomplished, for
example, by connecting the drive lines of the arrays 20a and 20c to
apply the first and second driving signals TX_P and TX_N. The
output lines 14a, 14b may also be connected to the common receive
line 22, and the AFE may thus receive measurement signals from the
cells of the multiple arrays 20a, 20c simultaneously. While two
arrays 20a, 20c are discussed in this embodiment, measurements may
be simultaneously collected from any number of arrays.
[0097] In some embodiments, a sensor area may include a plurality
of arrays that are arranged in logical groups, each logical group
including two or more arrays. Measurements from each array within a
given group may be collected simultaneously over a plurality of
timeslots, and the system may then iteratively switch to the next
group(s) in sequence to collect measurements from the arrays of
each group. For example, in an embodiment with two groups, a first
group may include half of the arrays of a sensor area, and a second
group may include the other half of the arrays of the sensor area.
Optionally, the arrays of the first group may be interleaved with
the arrays of the second group, such that adjacent arrays are not
driven simultaneously. Three, four, five, or more groups may be
used in some embodiments.
[0098] In some embodiments, the signals received from
simultaneously active arrays may be encoded according to a CDM
pattern, such that the received signals may be decoded to correlate
the measurement signals received to the array from which they were
received. For example, the measurement signals received by a given
output line may be passed to the AFE in an unmodified (+1) or
inverted (-1) form, in accordance with a CDM pattern. In some
embodiments, this modulation may be implemented using an encoding
circuit RX_EN, Additional states (e.g., grounded) may be
implemented as desired to accommodate CDM patterns with three or
more states.
[0099] In some embodiments, signals received by cells 10 may thus
be encoded twice. The signals received by the cells 10 of an array
20a may be encoded a first time, such that these signals may be
decoded to determine from which cell 10 in the array 20a a given
signal (or set of signals) was received. The signals received by
the array 20a, along with any other arrays in the same logical
group, may be encoded a second time, such that these signals may be
decoded to determine from which array a given signal (or set of
signals) was received. In such embodiments, the system may
therefore perform a first decoding step to a collection of signals
received over a given set of timeslots, thereby correlating
received signals to the correct respective array. The system may
then perform a second decoding step on the signals received from
each array, thereby correlating the signals received from that
array to the correct cell within that array.
[0100] FIG. 15 illustrates an exemplary method 600 for detecting a
portion of a user's body or other element. In some embodiments, the
method 600 may be performed using a system such as that described
above with respect to FIG. 14. For example, method 600 may be
performed in a system having a plurality of cells which may include
at least a first cell and a second cell. In some embodiments, each
cell of the plurality of cells may include a respective transmit
electrode, which may be configured to selectively apply a first
driving signal, and which may also be configured to selectively
apply a second driving signal that is inverted relative to the
first driving signal. In some embodiments, each cell of the
plurality of cells may further include a respective receive
electrode. In step 602, a first driving signal may be applied to
the first transmit electrode of the first cell during a first
timeslot. In step 604, also during the first timeslot, a first
measurement signal may be received using the receive electrode of
the first cell. In step 606, during a second timeslot, a second
driving signal may be applied to the transmit electrode of the
first cell. In step 608, also during the second timeslot, a second
measurement signal may be received using the receive electrode of
the first cell.
NUMBERED EMBODIMENTS
[0101] A1. A method for detecting a portion of a user's body, the
method being performed by a system comprising a plurality of cells,
each cell of the plurality of cells comprising a transmit electrode
and a receive electrode, the plurality of cells comprising a first
cell, wherein the method comprises:
in a first timeslot: applying a first driving signal to the
transmit electrode of the first cell; and receiving a first
measurement signal using the receive electrode of the first cell;
and in a second timeslot: applying a second driving signal to the
transmit electrode of the first cell; and receiving a second
measurement signal using the receive electrode of the first cell;
wherein the second driving signal is inverted relative to the first
driving signal.
[0102] A2. The method of embodiment A1, wherein the plurality of
cells comprises a first set of cells, the first set of cells
comprising at least the first cell and a second cell, each receive
electrode of the first set of cells being electrically connected to
a first output line, the method further comprising:
in the first timeslot: applying the second driving signal to the
transmit electrode of the second cell while the first driving
signal is applied to the transmit electrode of the first cell; and
receiving the first measurement signal using the first output line,
the first output line being electrically connected to the receive
electrodes of both the first cell and the second cell; in the
second timeslot: applying the first driving signal to the transmit
electrode of the second cell while the second driving signal is
applied to the transmit electrode of the first cell; and receiving
the second measurement signal using the first output line, the
first output line being electrically connected to the receive
electrodes of both the first cell and the second cell.
[0103] A3. The method of embodiment A2, wherein the plurality of
cells comprises a second set of cells, wherein no driving signal is
applied to the second set of cells during the first timeslot or the
second timeslot.
[0104] A4. The method of embodiment A3, wherein the first set of
cells is arranged in a first linear array, the second set of cells
is arranged in a second linear array, and the first linear array is
adjacent to the second linear array such that each cell of the
first set is adjacent to a respective cell of the second set.
[0105] A5. The method of any of embodiments A2-A4, wherein each
cell of the first set of cells has a first state and a second
state, wherein:
in the first state, the transmit electrode of the respective cell
is selectively connected to a first drive line that is configured
to apply the first driving signal; and in the second state, the
transmit electrode of the respective cell is selectively connected
to a second drive line that is configured to apply the second
driving signal.
[0106] A6. The method of embodiment A5, wherein the method
comprises:
applying the first and second states to the first set of cells over
a plurality of timeslots according to a multiplexing pattern;
receiving a plurality of measurement signals using the first output
line, wherein a respective measurement signal is received in each
timeslot of the plurality of timeslots; and processing the
plurality of measurement signals to obtain a respective measurement
for each cell of the first set of cells.
[0107] A7. The method of embodiment A6, wherein the plurality of
cells comprises a second set of cells, each receive electrode of
the second set being connected to a second output line, each cell
of the second set of cells having a first state and a second state,
wherein:
in the first state, the transmit electrode of the respective cell
of the second set is selectively connected to a first drive line of
the second set that is configured to apply the first driving
signal; and in the second state, the transmit electrode of the
respective cell of the second set is selectively connected to a
second drive line of the second set that is configured to apply the
second driving signal; the method further comprising: applying the
first and second states to the second set of cells over the
plurality of timeslots according to a multiplexing pattern, the
application of the first and second states to the second set of
cells occurring simultaneously with the application of the first
and second states to the first set of cells; receiving a plurality
of measurement signals using the second output line, wherein a
respective measurement signal is received using the second output
line in each timeslot of the plurality of timeslots; and processing
the plurality of measurement signals received using the second
output line to obtain a respective measurement for each cell of the
second set of cells.
[0108] A8. The method of embodiment A7, wherein the first output
line and the second output line are connected to a common analog
front end during the plurality of timeslots.
[0109] A9. The method of embodiment A8, further comprising:
encoding the measurement signals received using the first output
line and the measurement signals received using the second output
line during the first plurality of timeslots, such that the encoded
measurement signals are configured be combined and decoded to
separate the measurement signals received using the first output
line from the measurements received using the second output
line.
[0110] A10. The method of any of embodiments A2-A9, the method
further comprising:
obtaining measurements from at least the cells of the first set of
cells in a first set of timeslots; and obtaining measurements from
one or more additional sets of cells of the plurality of cells in
one or more subsequent sets of timeslots until at least one
measurement has been obtained from each cell of the plurality of
cells.
[0111] A11. A system for detecting a portion of a user's body, the
system comprising:
a plurality of cells comprising at least a first cell and a second
cell, wherein: each cell of the plurality of cells comprises a
respective transmit electrode, the respective transmit electrode
being configured to selectively apply a first driving signal, the
respective transmit electrode being further configured to
selectively apply a second driving signal that is inverted relative
to the first driving signal; each cell of the plurality of cells
further comprises a respective receive electrode; and the system is
configured to: apply, in a first timeslot, the first driving signal
to the transmit electrode of the first cell; and receive, in the
first timeslot, a first measurement signal using the receive
electrode of the first cell; and apply, in a second timeslot, the
second driving signal to the transmit electrode of the first cell;
and receive, in the second timeslot, a second measurement signal
using the receive electrode of the first cell.
[0112] A12. The system of embodiment A11, wherein:
the plurality of cells comprises a first set of cells, the first
set of cells comprising at least the first cell and a second cell;
each receive electrode of the first set of cells is electrically
connected to a first output line; and the system is further
configured to: apply, in the first timeslot, the second driving
signal to the transmit electrode of the second cell while the first
driving signal is applied to the transmit electrode of the first
cell; and receive, in the first timeslot, the first measurement
signal using the first output line, the first output line being
electrically connected to the receive electrodes of both the first
cell and the second cell; apply, in the second timeslot, the first
driving signal to the transmit electrode of the second cell while
the second driving signal is applied to the transmit electrode of
the first cell; and receive, in the second timeslot, the second
measurement signal using the first output line, the first output
line being electrically connected to the receive electrodes of both
the first cell and the second cell.
[0113] A13. The system of embodiment A12, wherein the plurality of
cells comprises a second set of cells, the system being configured
to apply no driving signal to the second set of cells during the
first timeslot or the second timeslot.
[0114] A14. The system of embodiment A13, wherein the first set of
cells is arranged in a first linear array, the second set of cells
is arranged in a second linear array, and the first linear array is
adjacent to the second linear array such that each cell of the
first set is adjacent to a respective cell of the second set.
[0115] A15. The system of any of embodiments A12-A14, wherein each
cell of the first set of cells has a first state and a second
state, such that:
in the first state, the transmit electrode of the respective cell
is selectively connected to a first drive line that is configured
to apply the first driving signal; and in the second state, the
transmit electrode of the respective cell is selectively connected
to a second drive line that is configured to apply the second
driving signal.
[0116] A16. The system of embodiment A15, wherein the system is
configured to:
apply the first and second states to the first set of cells over a
plurality of timeslots according to a multiplexing pattern; receive
a plurality of measurement signals using the first output line,
wherein a respective measurement signal is received in each
timeslot of the plurality of timeslots; and process the plurality
of measurement signals to obtain a respective measurement for each
cell of the first set of cells.
[0117] A17. The system of embodiment A16, wherein:
the plurality of cells comprises a second set of cells; each
receive electrode of the second set is connected to a second output
line; each cell of the second set of cells has a first state and a
second state, such that: in the first state, the transmit electrode
of the respective cell of the second set is selectively connected
to a first drive line of the second set that is configured to apply
the first driving signal; and in the second state, the transmit
electrode of the respective cell of the second set is selectively
connected to a second drive line of the second set that is
configured to apply the second driving signal; and the system is
configured to: apply the first and second states to the second set
of cells over the plurality of timeslots according to a
multiplexing pattern, the application of the first and second
states to the second set of cells occurring simultaneously with the
application of the first and second states to the first set of
cells; receive a plurality of measurement signals using the second
output line, wherein a respective measurement signal is received
using the second output line in each timeslot of the plurality of
timeslots; and process the plurality of measurement signals
received using the second output line to obtain a respective
measurement for each cell of the second set of cells.
[0118] A18. The system of embodiment A17, wherein the first output
line and the second output line are connected to a common analog
front end during the plurality of timeslots.
[0119] A19. The system of embodiment A18, wherein the system is
further configured to:
encode the measurement signals received using the first output line
and the measurement signals received using the second output line
during the first plurality of timeslots, such that the encoded
measurement signals are configured be combined and decoded to
separate the measurement signals received using the first output
line from the measurements received using the second output
line.
[0120] A20. The system of embodiment any of embodiments A12-A19,
wherein the system is further configured to:
obtain measurements from at least the cells of the first set of
cells in a first set of timeslots; and obtain measurements from one
or more additional sets of cells of the plurality of cells in one
or more subsequent sets of timeslots until at least one measurement
has been obtained from each cell of the plurality of cells.
[0121] B1. A method for detecting a portion of a user's body, the
method being performed by a system comprising a plurality of
electrodes, each electrode of the plurality of electrodes having at
least a first state in which a driving signal is applied to the
respective electrode and a second state in which said driving
signal is not applied to the respective electrode, the plurality of
electrodes comprising a first set of electrodes and a second set of
electrodes, the method comprising:
[0122] in a first timeslot: [0123] causing the first set of
electrodes to be in the first state such that the driving signal is
applied to the first set of electrodes, the application of the
driving signal to the first set of electrodes generating, at least
in part, a difference in voltage between the body portion and a
first set of detecting electrodes, the first set of detecting
electrodes being comprised within the plurality of electrodes;
[0124] causing the second set of electrodes to be in the second
state; and [0125] using the first set of detecting electrodes,
performing a first set of measurements, the first set of
measurements indicating whether the body portion or a component
thereof is within a detectable range of the first set of detecting
electrodes, wherein the first set of detecting electrodes is
identical to either the first set of electrodes or the second set
of electrodes; and in a second timeslot: [0126] causing the second
set of electrodes to be in the first state such that the driving
signal is applied to the second set of electrodes, the application
of the driving signal to the first second of electrodes generating,
at least in part, a difference in voltage between the body portion
and a second set of detecting electrodes, the second set of
detecting electrodes being comprised within the plurality of
electrodes; [0127] causing the first set of electrodes to be in the
second state; and [0128] using the second set of detecting
electrodes, performing a second set of measurements, the second set
of measurements indicating whether the body portion or the
component thereof is within a detectable range of the second set of
detecting electrodes.
[0129] B2. The method of embodiment B1, wherein the first set of
electrodes is identical to the first set of detecting electrodes,
and the second set of electrodes is identical to the second set of
detecting electrodes.
[0130] B3. The method of embodiment B2, further comprising:
[0131] in the first timeslot, causing the driving signal to be
applied to a third set of electrodes, the third set of electrodes
being adjacent to the first set of electrodes.
[0132] B4. The method of embodiment B3, wherein, during the first
timeslot, at least one electrode of the first set of electrodes is
connected to a first terminal of an analog front end, and at least
one electrode of the third set of electrodes is connected to a
second terminal of the analog front end.
[0133] B5. The method of embodiment B1, wherein the first set of
electrodes is identical to the second set of detecting electrodes,
and the second set of electrodes is identical to the first set of
detecting electrodes.
[0134] B6. The method of embodiment B5, further comprising:
[0135] in the first timeslot, causing a third set of electrodes to
be in a grounded state.
[0136] B7. The method of embodiment B6, wherein the third set of
electrodes in the grounded state are, during the first timeslot,
electrically connected to a shield that is coplanar with the
plurality of electrodes.
[0137] B8. The method of embodiment B5, wherein the first set of
electrodes is adjacent to the second set of electrodes, and the
first set of measurements comprises a first measurement indicating
that the body portion or component thereof modified a mutual
capacitance between an electrode of the first set of electrodes and
an electrode of the second set of electrodes.
[0138] B9. The method of embodiment B5, wherein the first timeslot
includes at least a first subpart, and the second state includes at
least a first detecting state wherein a respective electrode of the
plurality of electrodes is connected to a first terminal of an
analog front end and a second detecting state wherein the
respective electrode is connected to a second terminal of the
analog front end, the method further comprising: [0139] in the
first subpart of the first timeslot: [0140] causing a first
electrode of the second set of electrodes to be in the first
detecting state; [0141] causing a second electrode of the second
set of electrodes to be in the second detecting state; and [0142]
performing a first measurement of the first set of measurements,
the first measurement indicating, at least in part, a difference
between a first signal received from the first electrode and a
second signal received from the second electrode.
[0143] B10. A system for detecting a portion of a user's body, the
system comprising:
[0144] a plurality of electrodes;
[0145] each electrode of the plurality of electrodes having at
least a first state in which a driving signal is applied to the
respective electrode and a second state in which said driving
signal is not applied to the respective electrode;
[0146] the plurality of electrodes comprising a first set of
electrodes and a second set of electrodes;
[0147] wherein the system is configured to:
[0148] in a first timeslot: [0149] cause the first set of
electrodes to be in the first state such that the driving signal is
applied to the first set of electrodes, the application of the
driving signal to the first set of electrodes generating, at least
in part, a difference in voltage between the body portion and a
first set of detecting electrodes, the first set of detecting
electrodes being comprised within the plurality of electrodes;
[0150] cause the second set of electrodes to be in the second
state; and [0151] using the first set of detecting electrodes,
perform a first set of measurements, the first set of measurements
indicating whether the body portion or a component thereof is
within a detectable range of the first set of detecting electrodes,
wherein the first set of detecting electrodes is identical to
either the first set of electrodes or the second set of electrodes;
and in a second timeslot: [0152] cause the second set of electrodes
to be in the first state such that the driving signal is applied to
the second set of electrodes, the application of the driving signal
to the first second of electrodes generating, at least in part, a
difference in voltage between the body portion and a second set of
detecting electrodes, the second set of detecting electrodes being
comprised within the plurality of electrodes; [0153] cause the
first set of electrodes to be in the second state; and [0154] using
the second set of detecting electrodes, perform a second set of
measurements, the second set of measurements indicating whether the
body portion or the component thereof is within a detectable range
of the second set of detecting electrodes.
[0155] B11. The system of embodiment B10, wherein the first set of
electrodes is identical to the first set of detecting electrodes,
and the second set of electrodes is identical to the second set of
detecting electrodes.
[0156] B12. The system of embodiment B11, wherein the system is
further configured to:
[0157] cause, in the first timeslot, the driving signal to be
applied to a third set of electrodes, the third set of electrodes
being adjacent to the first set of electrodes.
[0158] B13. The system of embodiment B12, wherein, during the first
timeslot, at least one electrode of the first set of electrodes is
connected to a first terminal of an analog front end, and at least
one electrode of the third set of electrodes is connected to a
second terminal of the analog front end.
[0159] B14. The system of embodiment B10, wherein the first set of
electrodes is identical to the second set of detecting electrodes,
and the second set of electrodes is identical to the first set of
detecting electrodes.
[0160] B15. The system of embodiment B14, wherein the system is
further configured to cause, in the first timeslot, a third set of
electrodes to be in a grounded state.
[0161] B16. The system of embodiment B15, wherein the third set of
electrodes in the grounded state are, during the first timeslot,
electrically connected to a shield that is coplanar with the
plurality of electrodes.
[0162] B17. The system of embodiment B14, wherein the first set of
electrodes is adjacent to the second set of electrodes, and the
first set of measurements comprises a first measurement indicating
that the body portion or component thereof modified a mutual
capacitance between an electrode of the first set of electrodes and
an electrode of the second set of electrodes.
[0163] B18. The system of embodiment B14, wherein the first
timeslot includes at least a first subpart, and the second state
includes at least a first detecting state wherein a respective
electrode of the plurality of electrodes is connected to a first
terminal of an analog front end and a second detecting state
wherein the respective electrode is connected to a second terminal
of the analog front end; and
[0164] the system is further configured to, in the first subpart of
the first timeslot: [0165] cause a first electrode of the second
set of electrodes to be in the first detecting state; [0166] cause
a second electrode of the second set of electrodes to be in the
second detecting state; and [0167] perform a first measurement of
the first set of measurements, the first measurement indicating, at
least in part, a difference between a first signal received from
the first electrode and a second signal received from the second
electrode.
[0168] B19. A system for detecting a portion of a user's body, the
system comprising:
[0169] a plurality of electrodes, each electrode of the plurality
of electrodes having at least one driving state in which a driving
signal is applied to the respective electrode and at least one
non-driving state in which said driving signal is not applied to
the respective electrode;
[0170] a first set of electrodes within the plurality of
electrodes, the first set of electrodes being configured to receive
the driving signal in the driving state such that the first set of
electrodes generates, at least in part, a difference in voltage
between the body portion and at least one electrode of the
plurality of electrodes;
[0171] using the at least one electrode, performing a measurement,
the measurement indicating whether the body portion or a component
thereof is within a detectable range of the at least one
electrode.
[0172] B20. The system of embodiment 19, wherein the at least one
electrode is configured to be selectively controlled between the
driving state, a first detecting state wherein a respective
electrode of the plurality of electrodes is connected to a first
terminal of an analog front end and a second detecting state
wherein the respective electrode is connected to a second terminal
of an analog front end.
[0173] C1. A system for detecting a portion of a user's body, the
system comprising:
[0174] a plurality of electrodes, the plurality of electrodes being
configured to obtain signals indicative of a presence of the
portion of the user's body, the plurality of electrodes comprising
at least a first set of electrodes;
[0175] a plurality of output lines, the plurality of output lines
comprising a first output line, the first output line configured to
receive signals from at least a first electrode of the first set of
electrodes;
[0176] one or more shields, the one or more shields being
configured to shield one or more of the output lines of the
plurality of output lines from one or more electrodes of the
plurality of electrodes;
[0177] wherein the one or more shields are coplanar to the
plurality of electrodes and the first output line.
[0178] C2. The system of embodiment C1, wherein the plurality of
electrodes and the one or more shields are formed by a process
comprising:
[0179] depositing a layer of metal; and
[0180] removing some of the layer of metal, such that a remaining
portion of the layer of metal comprises the plurality of electrodes
and the one or more shields.
[0181] C3. The system of embodiment C1, wherein a shield of the one
or more shields is configured to be selectively electrically
connected to the first electrode of the first set of
electrodes.
[0182] C4. The system of embodiment C3, wherein the shield of the
one or more shields is configured to be grounded.
[0183] C5. The system of embodiment C3, wherein the shield of the
one or more shields is configured to receive a driving signal.
[0184] C6. The system of embodiment C3, wherein the first set of
electrodes comprises a first electrode and a second electrode, and
the one or more shields comprises a first shield and a second
shield, the first shield being adjacent to and at least partially
electrically isolating the first electrode, the second shield being
adjacent to and at least partially electrically isolating the
second electrode;
[0185] wherein the first shield is electrically connected to the
second shield.
[0186] C7. The system of embodiment C1, wherein the first electrode
of the first set of electrodes is configured to be selectively
electrically connected to the first output line; and
[0187] the first electrode of the first set of electrodes is
configured to be selectively electrically connected to a second
output line.
[0188] C8. The system of embodiment C1, wherein each electrode of
the first set of electrodes is configured to be selectively
electrically connected to the first output line, the first set of
electrodes comprising multiple electrodes; and
[0189] the plurality of electrodes further comprises a second set
of electrodes, each electrode of the second set of electrodes being
configured to be selectively connected to a second output line, the
second set of electrodes comprising multiple electrodes.
[0190] C9. The system of embodiment C8, wherein the one or more
shields comprises a first set of shields and a second set of
shields, each shield of the first set of shields being adjacent to
and at least partially electrically isolating a respective
electrode of the first set of electrodes, and each shield of the
second set of shields being adjacent to and at least partially
electrically isolating a respective electrode of the second set of
electrodes.
[0191] C10. The system of embodiment C9, wherein a first shield of
the first set of shields at least partially surrounds a first
electrode of the first set of electrodes, such that the first
shield comprises a first shield portion that is disposed between
the first electrode and the first output line and a second shield
portion that is disposed between the first electrode and the second
output line.
[0192] C11. The system of embodiment C10, wherein the first shield,
the first electrode of the first set of electrodes, and the second
output line are disposed in a first layer, the system further
comprising a supplemental shield, the supplemental shield being
disposed between the first electrode of the first set of electrodes
and the second output line, the supplemental shield being disposed
in a second layer that is different than the first layer.
[0193] C12. The system of embodiment C9, wherein each shield of the
first set of shields is configured to be selectively electrically
connected to its respective electrode of the first set of
electrodes, and each shield of the second set of shields is
configured to be selectively electrically connected to its
respective electrode of the second set of electrodes.
[0194] C13. The system of embodiment C12, wherein the shields of
the first set of shields are electrically connected to one-another,
and the shields of the second set of shields are electrically
connected to one-another.
[0195] C14. The system of embodiment C13, wherein a driving signal
is configured to be selectively applied to the first set of shields
while the driving signal is not applied to the second set of
shields; and the driving signal is configured to be selectively
applied to the second set of shields while the driving signal is
not applied to the first set of shields.
[0196] C15. The system of embodiment C1, wherein:
[0197] the first electrode of the first set of electrodes is
configured to be selectively connected to a driving line that is
configured to apply a driving signal; and
[0198] a first output line shield is disposed between the first
output line and the driving line.
[0199] C16. The system of embodiment C15, wherein the driving line
extends transversely to the first output line.
[0200] C17. The system of embodiment C15, wherein the first output
line is disposed in a first layer, the drive line is disposed in a
second layer, and the first output line shield is disposed in a
third layer, the third layer being between the first layer and the
second layer.
[0201] C18. The system of embodiment C1, wherein the first
electrode has multiple states, the multiple states comprising:
[0202] a detecting state in which the first electrode is connected
to the first output line; and
[0203] a driven state in which the first electrode receives a
driving signal.
[0204] C19. The system of embodiment C18, wherein the multiple
states further comprises a second detecting state, in which the
first electrode is connected to a second output line.
[0205] While the subject matter of this disclosure has been
described and shown in considerable detail with reference to
certain illustrative embodiments, including various combinations
and sub-combinations of features, those skilled in the art will
readily appreciate other embodiments and variations and
modifications thereof as encompassed within the scope of the
present disclosure. Moreover, the descriptions of such embodiments,
combinations, and sub-combinations is not intended to convey that
the claimed subject matter requires features or combinations of
features other than those expressly recited in the claims.
Accordingly, the scope of this disclosure is intended to include
all modifications and variations encompassed within the spirit and
scope of the following appended claims.
* * * * *