U.S. patent application number 13/834664 was filed with the patent office on 2014-05-08 for reducing movement and electrostatic interference in a non-resistive contact sensor assembly.
This patent application is currently assigned to RESCON LTD. The applicant listed for this patent is RESCON LTD. Invention is credited to Thomas Andrew DAWSON, Christian MACEDONIA.
Application Number | 20140125358 13/834664 |
Document ID | / |
Family ID | 50621777 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140125358 |
Kind Code |
A1 |
DAWSON; Thomas Andrew ; et
al. |
May 8, 2014 |
REDUCING MOVEMENT AND ELECTROSTATIC INTERFERENCE IN A NON-RESISTIVE
CONTACT SENSOR ASSEMBLY
Abstract
A non-resistive contact sensor assembly, including a
non-resistive contact sensor device, including a dry electrode
component, and a cover of anti-triboelectric material in which the
sensor device is surrounded or embedded.
Inventors: |
DAWSON; Thomas Andrew;
(Aldershot, GB) ; MACEDONIA; Christian; (Bethesda,
MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RESCON LTD |
FARNBOROUGH |
|
GB |
|
|
Assignee: |
RESCON LTD
FARNBOROUGH
GB
|
Family ID: |
50621777 |
Appl. No.: |
13/834664 |
Filed: |
March 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61671647 |
Jul 13, 2012 |
|
|
|
Current U.S.
Class: |
324/663 ;
324/658 |
Current CPC
Class: |
A61B 5/7207 20130101;
A61B 2562/182 20130101; A61B 5/6831 20130101; A61B 2562/0214
20130101; A61B 5/04 20130101; G01R 27/2605 20130101; G01R 29/12
20130101 |
Class at
Publication: |
324/663 ;
324/658 |
International
Class: |
G01R 27/26 20060101
G01R027/26 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0006] This invention was made with government support under
contract number W911NF-12-O-0004 awarded by DARPA. The government
has certain rights in the invention.
Claims
1. A non-resistive contact sensor assembly, comprising: (a) a
non-resistive contact sensor device, including a dry electrode
component; and (b) a cover of anti-triboelectric material in which
the sensor device is surrounded or embedded.
2. The non-resistive contact sensor assembly of claim 1, wherein
the anti-triboelectric material is a triboelectrically-neutral
material.
3. The non-resistive contact sensor assembly of claim 2, wherein
the triboelectrically-neutral material is cotton.
4. The non-resistive contact sensor assembly of claim 1, wherein
the anti-triboelectric material is triboelectrically-matched to the
surface being measured or tested.
5. The non-resistive contact sensor assembly of claim 4, wherein
the anti-triboelectric material is leather and is
triboelectrically-matched to skin.
6. The non-resistive contact sensor assembly of claim 4, further
comprising a housing that is treated with an ionized liquid.
7. A non-resistive contact sensor assembly, comprising: (a) a
non-resistive contact sensor device; (b) an inner region of
material in which the sensor device is surrounded or embedded; and
(c) an outer region of material; (d) wherein the inner and outer
regions mitigate movement of the sensor electrode relative to the
surface of the object being measured or tested; and (e) wherein the
inner and outer regions create a local area that is relatively
protected from the electrostatic build-up and electrical discharge
that may otherwise affect sensor performance.
8. The non-resistive contact sensor assembly of claim 7, wherein
the outer region includes an elastic material that is bound to, or
an extension of, a compressive type wearable article that aids in
holding the sensor assembly in place.
9. The non-resistive contact sensor assembly of claim 8, wherein
the compressive type wearable article is a garment.
10. The non-resistive contact sensor assembly of claim 8, wherein
the elastic material includes elastane.
11. The non-resistive contact sensor assembly of claim 8, wherein
the elastic material includes natural latex.
12. The non-resistive contact sensor assembly of claim 7, wherein
the outer region includes a conducting material that aids in
dissipation of charge to the surface of the entity, thereby
minimizing the chances that the charge will dissipate in a more
localized fashion within the area between the outer region the
sensor device.
13. The non-resistive contact sensor assembly of claim 7, wherein
the inner region includes a triboelectrically neutral or relatively
neutral material.
14. The non-resistive contact sensor assembly of claim 7, wherein
the inner region includes an elastic material that acts to hold the
sensor device in place, thereby minimizing the likelihood of sensor
movement against the object surface and leading, in turn, to less
chance of contact electrification and movement artifacts.
15. The non-resistive contact sensor assembly of claim 7, wherein
the inner region includes a biasing structure that acts to hold the
sensor device in place, thereby minimizing the likelihood of sensor
movement against the object surface and leading, in turn, to less
chance of contact electrification and movement artifacts.
16. The non-resistive contact sensor assembly of claim 15, wherein
the biasing structure includes a spring.
17. The non-resistive contact sensor assembly of claim 7, wherein
the inner region includes material that is relatively
triboelectrically matched to the surface of the object being
measured, tested, or the like, thereby minimizing the chances that
charge separation will occur when this region and the surface of
the object may move together.
18. The non-resistive contact sensor assembly of claim 7, wherein
the inner region includes material that is conductive, allowing for
dissipation of any surface or external charge.
19. The non-resistive contact sensor assembly of claim 7, further
comprising a housing that is treated with an ionized liquid.
20-39. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a U.S. non-provisional patent
application of, and claims priority under 35 U.S.C. .sctn.119(e)
to, U.S. provisional patent application Ser. No. 61/671,647 to
Dawson, filed Jul. 13, 2012 and entitled "REDUCING MOVEMENT AND
ELECTROSTATIC INTERFERENCE IN A NON-RESISTIVE CONTACT SENSOR
ASSEMBLY", which '647 application is incorporated by reference
herein in its entirety. Additionally, the entirety of each of the
following co-pending, commonly-assigned U.S. patent applications,
and any application publication thereof, is expressly incorporated
herein by reference: [0002] (a) U.S. provisional patent application
Ser. No. 61/695,986 to Dawson, filed Aug. 31, 2012 and entitled
"SIGNAL STABILIZATION IN A NON-RESISTIVE CONTACT SENSOR ASSEMBLY;"
[0003] (b) U.S. provisional patent application Ser. No. 61/759,827
to Dawson, filed Feb. 1, 2013 and entitled "SIGNAL STABILIZATION IN
A DIELECTRIC SENSOR ASSEMBLY;" [0004] (c) U.S. non-provisional
patent application Ser. No. 13/834,918, filed Mar. 15, 2013, and
entitled, "SIGNAL STABILIZATION IN A NON-RESISTIVE CONTACT SENSOR
ASSEMBLY;" and [0005] (d) U.S. non-provisional patent application
Ser. No. 13/835,762, filed Mar. 15, 2013, and entitled, "SIGNAL
STABILIZATION IN A DIELECTRIC SENSOR ASSEMBLY."
COPYRIGHT STATEMENT
[0007] All of the material in this patent document is subject to
copyright protection under the copyright laws of the United States
and other countries. The copyright owner has no objection to the
facsimile reproduction by anyone of the patent document or the
patent disclosure, as it appears in official governmental records
but, otherwise, all other copyright rights whatsoever are
reserved.
BACKGROUND OF THE PRESENT INVENTION
[0008] 1. Field of the Present Invention
[0009] The invention relates to methods that will attenuate or
eliminate unwanted movement or electrostatic interference on the
signal acquired from non-resistive contact sensors that are used
exclusively or in combination with other sensors and the sensor
data is utilized for detecting properties of an entity and entities
(biological or otherwise). For biological entities the invention
utilizes an electric field sensor or sensors for the measurement of
the structural and functional characteristics of organs and other
structures where the electric field sensor does not have resistive
contact with the organism, conferring multiple advantages. More
particularly, the invention relates to sensors, sensor housings,
fastenings and sensor systems including devices and installations
for assemblies for detecting structural and functional signatures
associated with electric potentials that may detect a displacement
signature within the geomagnetic field, and/or specific components
and/or structures that are a component of that entity or entities.
Specifically there is no resistive contact between the entity and
the signal transduction component of the electric field sensor or
sensors. Other sensor types may be added in to provide further
information such as for the identification and elimination or
attenuation of unwanted electrostatic or movement signal associated
with the recording of non-resistive contact electric fields from
that entity, in whatever state, such as during active or passive
movement.
[0010] 2. Background
[0011] Conventional electrodes act as a current transducer
converting ionic currents into electronic ones so
electrophysiological status can be assessed. The uses for this are
many and broadly range from assessment of neural (EEG), and cardiac
(ECG) and skeletal (EMG) muscle activity.
[0012] This approach requires conductive contact with the source
and has inherent problems. The first of these is the requirement of
clean skin exposure. This requirement may compromise continuous
usability due to the effects of environmental contaminants, both on
the skin and in the atmosphere; extremes of temperature and their
resulting general effect on skin due to physiological reactions
such as "goose bumps" and excessive sweating as well as other
phenomena; and potential reactions to conductive materials. The
process of preparing skin and securing a good conductive contact
can also decrease compliance, especially in if intended for
continuous day to day use. Furthermore, during exercise, the
physicality can result in electrodes being displaced. The other
issues include: shorting between electrodes, especially when placed
in close proximity to each other; and charge transfer which has
potential safety implications as well as the issue of the
measurement process corrupting the signal.
[0013] The problems, outlined above, are solved by the use of
capacitive electrodes (non-resistive contact sensors) as they
acquire signal through capacitive coupling, not requiring resistive
contact with the source. They provide many benefits, including the
fact that no electrical contact is required (and so no skin
preparation or conducting pads are necessary, and they can be
readily moved or relocated to get an optimal signal), they can be
miniaturized, they have very low power requirements, and they can
be embodied as passive electric field sensors with the result that
adjacent sensors do not interfere with each other.
[0014] The use of capacitive electrodes for electrophysiological
monitoring is not a recent innovation, with Richardson describing
it for acquisition of the cardiac signal in 1967 (see The insulated
electrode: a pasteless electrocardiographic technique. Richardson P
C. Proc. Annu Conf. on Engineering in Medicine and Biology 7:
9-15(1967)). This system was, however, flawed being prone to
problems including poor signal to noise ratio, voltage drift,
electrostatic discharge and parasitic capacitance. These are still
problems with capacitive sensor technologies today. Many of those
problems have been addressed, at least partially, however problems
with electrostatic interference still plague this technology.
Electrostatic interference is especially problematic during
movement. Movement may lead to a variety of issues that may
compromise continuous signal acquisition including: contact
electrification between the body surface and the sensor electrode;
charge build-up on the body resulting in baseline shift and
potential saturation if occurs too rapidly; and movement of the
sensor relative to the body that can also lead to baseline shift
and saturation (railing).
[0015] The use of dry electrodes pressed into direct contact with
the person may create triboelectric effects. That is, electrical
charges created by sliding friction and pressure. Triboelectric
effects of this nature may cause contact electrification where
static charges may be delivered to the pick-up electrode. This
static charge can produce a near direct current (DC) or very low
frequency drift in sensor that may interfere with the physiological
alternating current (AC) that is being measured or saturate the
sensor causing railing, after which the sensor takes time to return
to being able to produce a useful physiologically relevant output.
If the electrode moves relative to the body, it will also pick up a
geoelectric displacement signal. That is, the effect of the body,
an electrically active structure, moving through the geoelectric
field that is of the order of 100 Vm.sup.-1 will cause relative
polarization of the sensor that will displace the baseline and may
cause the sensor to saturate. An additional source of interference
is that of clothing moving on the body. As clothing moves on the
body then charge separation can occur when materials that are
separated on the triboelectric series donate or receive electrons
from each other. After a material becomes charged it may discharge
onto the surface of where an electric potential may be being
measured thereby interfering with signal acquisition. Cotton is a
relative exception to this as it is essentially triboelectrically
neutral, or does not accept or give up electrons, so charge
separation tends not to occur.
SUMMARY OF THE PRESENT INVENTION
[0016] In accordance with one aspect of the invention, a sensor for
use with an entity may have a fixed wrapping that is:
triboelectrically neutral, such as cotton; triboelectrically
matched to the surface being measured, such as leather to skin; or
any combination thereof. This aspect of the invention will minimize
the likelihood of contact electrification from movement of the dry
electrode sensor against the skin.
[0017] In accordance with another aspect of the invention, a sensor
for use with an entity may be surrounded or embedded in a material
that is in full or partial contact with the entity that is:
triboelectrically neutral, such as cotton; triboelectrically
matched to the surface being measured, such as leather to skin; has
conducting components in it that act to dissipate charge to prevent
electrostatic build-up; has a compressive or elastic component that
pushes the electrode into the surface of the entity to minimize the
likelihood of sensor movement relative to the entity; or a
combination or permutation of the foregoing. This embodiment of the
invention will help minimize the effects of local electrostatic
build-up and electrical discharge that may affect the electrode
performance, causing drift or saturation.
[0018] In accordance with another aspect of the invention diodes
may be used for charge transfer away from the sensor.
[0019] In accordance with another aspect of the invention the
surface region of the entity where a sensor or sensors are housed
may be separated from the rest of the surface entity of the entity
using a conducting band.
[0020] In accordance with another aspect of the invention the
sensor may have an electrostatic shield layer, such as a layer of
neoprene, over it. On top of this layer may be an additional layer
or layers, such as for the dispersion of unwanted electrical charge
away from the electrode area to the surface of the entity.
[0021] Broadly defined, the present invention according to one
aspect is a non-resistive contact sensor assembly, including: a
non-resistive contact sensor device, including a dry electrode
component; and a cover of anti-triboelectric material in which the
sensor device is surrounded or embedded.
[0022] In a feature of this aspect, the anti-triboelectric material
is a triboelectrically-neutral material. In another feature, the
triboelectrically-neutral material is cotton.
[0023] In another feature of this aspect, the anti-triboelectric
material is triboelectrically-matched to the surface being measured
or tested. In another feature, the anti-triboelectric material is
leather and is triboelectrically-matched to skin.
[0024] In another feature, the non-resistive contact sensor
assembly further includes a housing that is treated with an ionized
liquid.
[0025] Broadly defined, the present invention according to another
aspect is a non-resistive contact sensor assembly, including: a
non-resistive contact sensor device; an inner region of material in
which the sensor device is surrounded or embedded; and an outer
region of material; wherein the inner and outer regions mitigate
movement of the sensor electrode relative to the surface of the
object being measured or tested; and wherein the inner and outer
regions create a local area that is relatively protected from the
electrostatic build-up and electrical discharge that may otherwise
affect sensor performance.
[0026] In a feature of this aspect, the outer region includes an
elastic material that is bound to, or an extension of, a
compressive type wearable article that aids in holding the sensor
assembly in place. In further features, the compressive type
wearable article is a garment; and/or the elastic material includes
elastane and/or natural latex.
[0027] In another feature of this aspect, the outer region includes
a conducting material that aids in dissipation of charge to the
surface of the entity, thereby minimizing the chances that the
charge will dissipate in a more localized fashion within the area
between the outer region the sensor device.
[0028] In another feature of this aspect, the inner region includes
a triboelectrically neutral or relatively neutral material.
[0029] In another feature of this aspect, the inner region includes
an elastic material that acts to hold the sensor device in place,
thereby minimizing the likelihood of sensor movement against the
object surface and leading, in turn, to less chance of contact
electrification and movement artifacts.
[0030] In another feature of this aspect, the inner region includes
a biasing structure that acts to hold the sensor device in place,
thereby minimizing the likelihood of sensor movement against the
object surface and leading, in turn, to less chance of contact
electrification and movement artifacts. In a further feature, the
biasing structure includes a spring.
[0031] In another feature of this aspect, the inner region includes
material that is relatively triboelectrically matched to the
surface of the object being measured, tested, or the like, thereby
minimizing the chances that charge separation will occur when this
region and the surface of the object may move together.
[0032] In another feature of this aspect, inner region includes
material that is conductive, allowing for dissipation of any
surface or external charge.
[0033] In another feature, the non-resistive contact sensor
assembly further includes a housing that is treated with an ionized
liquid.
[0034] Broadly defined, the present invention according to another
aspect is a non-resistive contact sensor assembly, including: a
non-resistive contact sensor device; a first inner region of
material in which the sensor device is surrounded or embedded; a
boundary region, around the first inner region, that is at least
partly comprised of a conducting material and that picks up
electrical charge from the first inner region; a second inner
region around the boundary region; an outer region around the
second inner region; and at least one diode, disposed in the second
inner region and connected between the boundary region through the
second inner region to the outer region.
[0035] In a feature of this aspect, at least one of the first inner
region, the second inner region, and the outer region includes a
triboelectrically neutral or relatively neutral material.
[0036] In another feature of this aspect, at least one of the first
inner region, the second inner region, and the outer region
includes an elastic material that acts to hold the sensor device in
place, thereby minimizing the likelihood of sensor movement against
the object surface and leading, in turn, to less chance of contact
electrification and movement artifacts.
[0037] In another feature of this aspect, at least one of the first
inner region, the second inner region, and the outer region
includes a biasing structure that acts to hold the sensor device in
place, thereby minimizing the likelihood of sensor movement against
the object surface and leading, in turn, to less chance of contact
electrification and movement artifacts. In a further feature, the
biasing structure includes a spring.
[0038] In another feature of this aspect, at least one of the first
inner region, the second inner region, and the outer region
includes material that is relatively triboelectrically matched to
the surface of the object being measured, tested, or the like,
thereby minimizing the chances that charge separation will occur
when this region and the surface of the object may move
together.
[0039] In another feature of this aspect, at least one of the first
inner region, the second inner region, and the outer region
includes material that is conductive, allowing for dissipation of
any surface or external charge.
[0040] In another feature, the non-resistive contact sensor
assembly further includes a housing that is treated with an ionized
liquid.
[0041] Broadly defined, the present invention according to another
aspect is a non-resistive contact sensor assembly, wherein the
surface region of the entity where a sensor or sensors are housed
may be separated from the rest of the surface of the entity using a
conducting band, including: a non-resistive contact sensor device,
including a dry electrode component; a first region of material;
and a second region of material, wherein at least part of the
material is a conducting material; wherein the first region is
walled off from the rest of the surface of the entity by the second
region.
[0042] In a feature of this aspect, the assembly is provided in a
wearable form. In another feature, the assembly is provided in the
form of a belt or wrap to be worn around a portion of a human body.
In a further feature, the assembly is provided in the form of a
belt or wrap to be worn around the midsection of a human.
[0043] In another feature, the non-resistive contact sensor
assembly further includes a housing that is treated with an ionized
liquid.
[0044] Broadly defined, the present invention according to another
aspect is a non-resistive contact sensor assembly, including: a
non-resistive contact sensor device, including a dry electrode
component; and an electrostatic shield layer disposed over the
sensor device.
[0045] In a feature of this aspect, the electrostatic shield layer
is a triboelectrically-neutral material.
[0046] In another feature of this aspect, the electrostatic shield
layer is a electrostatically-shielding material.
[0047] In another feature of this aspect, the electrostatic shield
layer extends out from the sensor on the surface of the entity
being measured or tested.
[0048] In another feature of this aspect, the sensor assembly
further includes a conducting layer disposed over the electrostatic
shield layer. In a further feature, the conducting layer extends
out from the outer perimeters of the electrostatic shield layer to
the surface of the entity.
[0049] In another feature, the non-resistive contact sensor
assembly further includes a housing that is treated with an ionized
liquid.
[0050] Broadly defined, the present invention according to another
aspect is a non-resistive contact sensor assembly as shown and
described.
[0051] Broadly defined, the present invention according to another
aspect is a method of reducing movement in a non-resistive contact
sensor assembly, as shown and described.
[0052] Broadly defined, the present invention according to another
aspect is a method of reducing electrostatic interference in a
non-resistive contact sensor assembly, as shown and described.
[0053] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific
examples, while indicating the preferred embodiment of the
invention, are intended for purposes of illustration only and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] Further features, embodiments, and advantages of the present
invention will become apparent from the following detailed
description with reference to the drawings, wherein:
[0055] FIG. 1A is a schematic diagram illustrating the use of a
non-resistive contact sensor assembly in accordance with a first
preferred embodiment of the present invention;
[0056] FIG. 1B is a schematic diagram of another non-resistive
contact sensor assembly;
[0057] FIG. 2 is a schematic diagram of a non-resistive contact
sensor assembly in accordance with another preferred embodiment of
the present invention;
[0058] FIG. 3 is a schematic diagram of a non-resistive contact
sensor assembly in accordance with another preferred embodiment of
the present invention;
[0059] FIG. 4 is a schematic diagram illustrating the use of a
non-resistive contact sensor assembly 310 in accordance with
another preferred embodiment of the present invention; and
[0060] FIG. 5 is a schematic diagram of a non-resistive contact
sensor assembly in accordance with another preferred embodiment of
the present invention.
DETAILED DESCRIPTION
[0061] As a preliminary matter, it will readily be understood by
one having ordinary skill in the relevant art ("Ordinary Artisan")
that the present invention has broad utility and application.
Furthermore, any embodiment discussed and identified as being
"preferred" is considered to be part of a best mode contemplated
for carrying out the present invention. Other embodiments also may
be discussed for additional illustrative purposes in providing a
full and enabling disclosure of the present invention. As should be
understood, any embodiment may incorporate only one or a plurality
of the above-disclosed aspects of the invention and may further
incorporate only one or a plurality of the above-disclosed
features. Moreover, many embodiments, such as adaptations,
variations, modifications, and equivalent arrangements, will be
implicitly disclosed by the embodiments described herein and fall
within the scope of the present invention.
[0062] Accordingly, while the present invention is described herein
in detail in relation to one or more embodiments, it is to be
understood that this disclosure is illustrative and exemplary of
the present invention, and is made merely for the purposes of
providing a full and enabling disclosure of the present invention.
The detailed disclosure herein of one or more embodiments is not
intended, nor is to be construed, to limit the scope of patent
protection afforded the present invention, which scope is to be
defined by the claims and the equivalents thereof. It is not
intended that the scope of patent protection afforded the present
invention be defined by reading into any claim a limitation found
herein that does not explicitly appear in the claim itself.
[0063] Thus, for example, any sequence(s) and/or temporal order of
steps of various processes or methods that are described herein are
illustrative and not restrictive. Accordingly, it should be
understood that, although steps of various processes or methods may
be shown and described as being in a sequence or temporal order,
the steps of any such processes or methods are not limited to being
carried out in any particular sequence or order, absent an
indication otherwise. Indeed, the steps in such processes or
methods generally may be carried out in various different sequences
and orders while still falling within the scope of the present
invention. Accordingly, it is intended that the scope of patent
protection afforded the present invention is to be defined by the
appended claims rather than the description set forth herein.
[0064] Additionally, it is important to note that each term used
herein refers to that which the Ordinary Artisan would understand
such term to mean based on the contextual use of such term herein.
To the extent that the meaning of a term used herein--as understood
by the Ordinary Artisan based on the contextual use of such
term--differs in any way from any particular dictionary definition
of such term, it is intended that the meaning of the term as
understood by the Ordinary Artisan should prevail.
[0065] Regarding applicability of 35 U.S.C. .sctn.112, 6, no claim
element is intended to be read in accordance with this statutory
provision unless the explicit phrase "means for" or "step for" is
actually used in such claim element, whereupon this statutory
provision is intended to apply in the interpretation of such claim
element.
[0066] Furthermore, it is important to note that, as used herein,
"a" and "an" each generally denotes "at least one," but does not
exclude a plurality unless the contextual use dictates otherwise.
Thus, reference to "a picnic basket having an apple" describes "a
picnic basket having at least one apple" as well as "a picnic
basket having apples." In contrast, reference to "a picnic basket
having a single apple" describes "a picnic basket having only one
apple."
[0067] When used herein to join a list of items, "or" denotes "at
least one of the items," but does not exclude a plurality of items
of the list. Thus, reference to "a picnic basket having cheese or
crackers" describes "a picnic basket having cheese without
crackers," "a picnic basket having crackers without cheese," and "a
picnic basket having both cheese and crackers." Finally, when used
herein to join a list of items, "and" denotes "all of the items of
the list." Thus, reference to "a picnic basket having cheese and
crackers" describes "a picnic basket having cheese, wherein the
picnic basket further has crackers," as well as describes "a picnic
basket having crackers, wherein the picnic basket further has
cheese."
[0068] Referring now to the drawings, in which like numerals
represent like components throughout the several views, one or more
preferred embodiments of the present invention are next described.
The following description of one or more preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0069] The invention relates to methods for attenuating or
eliminating unwanted electrostatic interference or "movement" on
the signals acquired from non-resistive contact sensors that are
utilized for detecting properties of an entity and entities
(biological or otherwise). The invention has applicability both for
sensors used exclusively and for sensors used in combination with
other sensors. For biological entities, the invention utilizes an
electric field sensor or sensors, for the measurement of the
structural and functional characteristics of organs and other
structures, where the electric field sensor does not have resistive
contact with the organism, conferring multiple advantages.
[0070] More particularly, the invention relates to sensors, sensor
housings, fastenings and sensor systems including devices and
installations for assemblies for detecting structural and
functional signatures associated with electric potentials that may
detect a displacement signature within the geomagnetic field,
and/or specific components and/or structures that are a component
of that entity or entities. Specifically there is no resistive
contact between the entity and the signal transduction component of
the electric field sensor or sensors. Other sensor types may be
added in to provide further information such as for the
identification and elimination or attenuation of unwanted
electrostatic or movement signal associated with the recording of
non-resistive contact electric fields from that entity, in whatever
state, such as during active or passive movement.
[0071] This invention describes novel methods to mitigate
electrostatic and movement interference when using an electric
field sensor or sensors that does not have resistive contact with
the entity, generally an organism, being monitored. The invention
includes combinations and permutations of: using neutral and/or
closely matched triboelectric materials to mitigate against the
potential for charge (electron) transfer during movement; using
conductive materials to dissipate or block charge transfer from the
entity or an external source to the non-resistive contact sensor
head; using of compressive materials and/or biasing structures to
hold the sensor head firmly against the surface of the entity being
monitored; using triboelectrically neutral materials (i.e.,
materials that do not accept or release electrons) to minimize the
likelihood for charge transfer to an area where a sensor is; using
diodes to transfer charge away from a sensor; and using an ionized
liquid to dissipate charge, minimizing static build-up.
[0072] FIG. 1A is a schematic diagram illustrating the use of a
non-resistive contact sensor assembly 10 in accordance with a first
preferred embodiment of the present invention. The sensor assembly
10 includes a sensor device 12 at least partially surrounded by, or
embedded in, a cover 14 of anti-triboelectric material. The sensor
device 12 includes a dry electrode component 16 that is interior to
the cover 14. In some embodiments, the anti-triboelectric material
may be a triboelectrically-neutral material, such as cotton. In
some embodiments, the anti-triboelectric material may be a material
that is triboelectrically matched to the surface 20 of an object to
which the sensor is being applied. For example, if the surface is
human skin, then the anti-triboelectric material may be leather,
which is triboelectrically matched to human skin. The cover 14 is
preferably physically bound to the sensor device 12, and in at
least some embodiments is physically bound to the dry electrode
component 16 portion of the sensor.
[0073] As shown in FIG. 1A, when the sensor assembly is placed
against the surface 20, the anti-triboelectric material helps
prevent (minimizing or even eliminating) contact electrification 30
that would otherwise occur as a result of the triboelectric
separation between the dry electrode component 16 and the surface
20 and movement of the dry electrode component 16 against the
surface 20. By contrast, FIG. 1B is a schematic diagram of another
non-resistive contact sensor assembly 60. This sensor assembly 60
likewise includes a sensor device 62 having a dry electrode
component 66, but in the absence of the anti-triboelectric
material, contact electrification 30 can and does occur frequently.
This, in turn, may cause interference with the target signal
acquisition including unwanted noise and/or sensor
saturation/railing.
[0074] It will be appreciated that in the sensor assembly 10 of
FIG. 1A, the cover 14 may utilize a combination of a
triboelectrically neutral material with a triboelectrically matched
material, and/or may utilize a material having a combination of
triboelectrically neutral properties and triboelectrically matching
properties. Furthermore, it will be appreciated that the sensor
device 12 may be embedded in the cover 14 rather than merely being
surrounded by the cover 14.
[0075] FIG. 2 is a schematic diagram of a non-resistive contact
sensor assembly 110 in accordance with another preferred embodiment
of the present invention. In this sensor assembly, two regions
142,144 surround a sensor device 112, including a dry electrode
component (not separately shown). The two regions 142,144 mitigate
movement of the sensor electrode relative to the surface of the
object being measured, tested, or the like, or create a local area
that is relatively protected from the electrostatic build-up and
electrical discharge that may otherwise affect sensor performance.
An outer region 142 may composed of an elastic or other material
that is bound to, or an extension of, a compressive type wearable
article, such as a garment, that aids in holding the sensor
assembly 110 in place. In various embodiments, the elastic material
may include elastane, natural latex, or both. This region may also
include a conducting material that aids in dissipation of charge to
the surface of the entity, thereby minimizing the chances that the
charge will dissipate in a more localized fashion within the area
between the outer region 142 the sensor device 112. The outer
region 142 could also include a combination of a
fastening/elastic/compressive and conductive materials.
[0076] In at least some embodiments, an inner region 144 could
include a triboelectrically neutral or relatively neutral material,
such as but not limited to cotton. One purpose in using such
material is to avoid the buildup of electrostatic or other charges,
because the material will be at least relatively resistant to, if
not able to avoid altogether, accepting or donating electrons.
Further, in at least some embodiments, the inner region 144 could
include an elastic material, a biasing structure, or both, that
acts or act to hold the sensor device 112 in place, thereby
minimizing the likelihood of sensor movement against the object
surface and leading, in turn, to less chance of contact
electrification and movement artifacts. Further, in at least some
embodiments, the inner region 144 could include material that is
relatively triboelectrically matched to the surface of the object
being measured, tested, or the like, thereby minimizing the chances
that charge separation will occur when this region 144 and the
surface of the object may move together. Further, in at least some
embodiments, the inner region 144 could include material that is
conductive, allowing for dissipation of any surface or external
charge. Finally, it will also be appreciated that the inner region
144 could further be comprised of any combination or permutation of
the foregoing types of materials.
[0077] FIG. 3 is a schematic diagram of a non-resistive contact
sensor assembly 210 in accordance with another preferred embodiment
of the present invention. In this sensor assembly 210, diodes 250
may be used for charge transfer away from a sensor device 212. The
sensor device 212 is surrounded by, or embedded in, a first inner
region 242 where electrical charge is picked up by a boundary
region 246 that is comprised at least partly, if not completely, of
a conducting material. This charge is then transferred through a
second inner region 248, via a diode or network of diodes 250, to
an outer region 244.
[0078] In various embodiments, each region 242,244,248, other than
the boundary region 246, could include a triboelectrically neutral
or relatively neutral material, such as but not limited to cotton.
One purpose in using such material is to avoid the buildup of
electrostatic or other charges, because the material will be at
least relatively resistant to, if not able to avoid altogether,
accepting or donating electrons. Further, in various embodiments,
each region 242,244,248, other than the boundary region 246, could
include an elastic material, a biasing structure, or both, that
acts or act to hold the sensor device 212 in place, thereby
minimizing the likelihood of sensor movement against the object
surface and leading, in turn, to less chance of contact
electrification and movement artifacts. Further, in various
embodiments, each region 242,244,248, other than the boundary
region 246, could include material that is relatively
triboelectrically matched to the surface of the object being
measured, tested, or the like, thereby minimizing the chances that
charge separation will occur when such region 242,244,248 and the
surface of the object may move together. Further, in various
embodiments, each region 242,244,248, other than the boundary
region 246, could include material that is conductive, allowing for
dissipation of any surface or external charge. Finally, it will
also be appreciated that each region 242,244,248, other than the
boundary region 246, could further be comprised of any combination
or permutation of the foregoing types of materials.
[0079] FIG. 4 is a schematic diagram illustrating the use of a
non-resistive contact sensor assembly 310 in accordance with
another preferred embodiment of the present invention. In this
sensor assembly 310, the surface region of the entity where a
sensor or sensors are housed may be separated from the rest of the
surface of the entity using a conducting band. More particularly,
one or more sensor devices 312 are surrounded by, or within, a
first region 344 that is walled off from the rest of the surface of
the entity by a second region 342 that is comprised at least
partly, if not completely, of a conducting material. Such a sensor
assembly 310 may be provided in a wearable form, such as in the
form of a belt or wrap to be worn around the midsection, including
thoracic region (chest or upper back) or abdomen, arm, leg, head,
or other body portion of a human 320.
[0080] In at least some embodiments, the first region 344 could
include a triboelectrically neutral or relatively neutral material,
such as but not limited to cotton. One purpose in using such
material is to avoid the buildup of electrostatic or other charges,
because the material will be at least relatively resistant to, if
not able to avoid altogether, accepting or donating electrons.
Further, in at least some embodiments, the first region 344 could
include an elastic material, a biasing structure, or both, that
acts or act to hold the sensor device 312 in place, thereby
minimizing the likelihood of sensor movement against the object
surface and leading, in turn, to less chance of contact
electrification and movement artifacts. Further, in at least some
embodiments, the first region 344 could include material that is
relatively triboelectrically matched to the surface of the object
being measured, tested, or the like, thereby minimizing the chances
that charge separation will occur when this region 344 and the
surface of the object may move together. Further, in at least some
embodiments, the first region 344 could include material that is
conductive, allowing for dissipation of any surface or external
charge. Finally, it will also be appreciated that the first region
344 could further be comprised of any combination or permutation of
the foregoing types of materials.
[0081] FIG. 5 is a schematic diagram of a non-resistive contact
sensor assembly 410 in accordance with another preferred embodiment
of the present invention. This sensor assembly 410 includes a
sensor device 412, having a dry electrode component 416, that has
an electrostatic shield layer 424 over it. More particularly, the
sensor device 412 has a layer 424 of triboelectrically-neutral or
electrostatically-shielding material over it, extending out from
the sensor on the surface 420 of the entity being measured, tested,
or the like. One material suitable for such a layer 424 is
neoprene. In at least some embodiments, one or more additional
layer 422 is disposed over the triboelectrically-neutral or
electrostatically-shielding layer 424. Such a layer 422 may
comprise, in whole or in part, a conducting material for the
dispersion of unwanted electrical charge away from the electrode
area to the surface of the entity. The conducting layer 422 extends
out from the outer perimeters of the triboelectrically-neutral or
electrostatically-shielding layer 424 to the surface 420 of the
entity. At least one purpose of the conducting layer 422 is to
dissipate charge that may occur from external sources, such as
moving clothing, away from the sensor electrode 416 and from the
surface local to the electrode 416, thereby minimizing the
likelihood of sensor drift or saturation.
[0082] In at least some embodiments, the conducting layer 422 could
include a triboelectrically neutral or relatively neutral material,
such as but not limited to cotton. Further, in at least some
embodiments, the conducting layer 422 could include an elastic
material, a biasing structure, or both, that acts or act to hold
the sensor device 412 in place, thereby minimizing the likelihood
of sensor movement against the object surface and leading, in turn,
to less chance of contact electrification and movement artifacts.
Further, in at least some embodiments, the conducting layer 422
could include material that is relatively triboelectrically matched
to the surface of the object being measured, tested, or the like,
thereby minimizing the chances that charge separation will occur
when this layer 422 and the surface of the object may move
together. Finally, there may be other layers to shield, hold, or
protect the sensor device 412.
[0083] In at least some embodiments, including variations of the
embodiments described hereinabove, the area being measured, tested,
or the like, the sensor housing, and/or clothing worn by a user may
be treated with an ionized liquid, such as tap water.
[0084] Various advantages may be achieved using one or more of the
foregoing embodiments of the present invention. An enhanced
signal-to-noise ratio may be achieved for electric field sensors.
The effect of electrostatic charge interference with electric field
sensors may be minimized or obliterated. The use of electric field
sensors during exercise and daily activities may be increased.
Usability of electric field sensors with different types of
clothing may be improved. The usability of electric field sensors
when clothing is moving, such as when it is flapping in the wind,
may be improved. The usability of electric field sensors when there
is external contact that may knock the sensor may be improved. The
usability of electric field sensors may be improved when there is
external contact that may result in charge transfer to the entity
being measured. The likelihood of contact electrification, sensor
DC drift, and sensor saturation may all be decreased.
[0085] Based on the foregoing information, it will be readily
understood by those persons skilled in the art that the present
invention is susceptible of broad utility and application. Many
embodiments and adaptations of the present invention other than
those specifically described herein, as well as many variations,
modifications, and equivalent arrangements, will be apparent from
or reasonably suggested by the present invention and the foregoing
descriptions thereof, without departing from the substance or scope
of the present invention.
[0086] Accordingly, while the present invention has been described
herein in detail in relation to one or more preferred embodiments,
it is to be understood that this disclosure is only illustrative
and exemplary of the present invention and is made merely for the
purpose of providing a full and enabling disclosure of the
invention. The foregoing disclosure is not intended to be construed
to limit the present invention or otherwise exclude any such other
embodiments, adaptations, variations, modifications or equivalent
arrangements; the present invention being limited only by the
claims appended hereto and the equivalents thereof.
* * * * *