U.S. patent application number 10/213730 was filed with the patent office on 2004-12-02 for device for capturing thermal spectra from tissue.
Invention is credited to Agostino, Mark D., Braig, James R., Cortella, Julian M., Goldberger, Daniel S., Hartstein, Philip C., Herrera, Roger O., Rule, Peter, Smith, Heidi M., Witte, Kenneth G..
Application Number | 20040242975 10/213730 |
Document ID | / |
Family ID | 26908357 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040242975 |
Kind Code |
A9 |
Rule, Peter ; et
al. |
December 2, 2004 |
Device for capturing thermal spectra from tissue
Abstract
A device and method are provided for use with a noninvasive
optical measurement system, such as a thermal gradient
spectrometer, for improved determination of analyte concentrations
within living tissue. In one embodiment, a wearable window is
secured to a patient's forearm thereby isolating a measurement site
on the patient's skin for determination of blood glucose levels.
The wearable window effectively replaces a window of the
spectrometer, and thus forms an interface between the patient's
skin and a thermal mass window of the spectrometer. When the
spectrometer must be temporarily removed from the patient's skin,
such as to allow the patient mobility, the wearable window is left
secured to the forearm so as to maintain a consistent measurement
site on the skin. When the spectrometer is later reattached to the
patient, the wearable window will again form an interface between
the spectrometer and the same location of skin as before.
Inventors: |
Rule, Peter; (Los Altos
Hills, CA) ; Braig, James R.; (Piedmont, CA) ;
Goldberger, Daniel S.; (Boulder, CO) ; Cortella,
Julian M.; (Alameda, CA) ; Smith, Heidi M.;
(Union City, CA) ; Herrera, Roger O.; (Emeryville,
CA) ; Witte, Kenneth G.; (San Jose, CA) ;
Hartstein, Philip C.; (Cupertino, CA) ; Agostino,
Mark D.; (Alameda, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
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Prior
Publication: |
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Document Identifier |
Publication Date |
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US 0040663 A1 |
February 27, 2003 |
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Family ID: |
26908357 |
Appl. No.: |
10/213730 |
Filed: |
August 6, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10213730 |
Aug 6, 2002 |
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09760423 |
Jan 11, 2001 |
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6636753 |
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09760423 |
Jan 11, 2001 |
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09265195 |
Mar 10, 1999 |
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6198949 |
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60310898 |
Aug 8, 2001 |
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Current U.S.
Class: |
600/309 |
Current CPC
Class: |
G01N 2021/0389 20130101;
A61B 5/14532 20130101; G01N 21/35 20130101; G01J 3/0286 20130101;
G01N 2201/021 20130101; G01J 3/0291 20130101; A61B 5/01 20130101;
A61B 5/6824 20130101; G01N 2201/0245 20130101; G01N 21/01 20130101;
A61B 5/061 20130101 |
Class at
Publication: |
600/309 |
International
Class: |
A61B 005/00 |
Claims
What is claimed is:
1. A device for use with a noninvasive optical measurement system
for capturing thermal spectra from living tissue, said device
comprising: a window holder; and a window connected to said window
holder, said window comprising a material of high thermal
conductivity so as to permit thermal spectra to pass through said
window; said device defining a skin contact surface configured for
placement in intimate thermal contact with the skin of a patient;
said device further defining a system contact surface opposite said
skin contact surface; said system contact surface being configured
for removable placement against said noninvasive optical
measurement system.
2. The device of claim 1, wherein said window holder has an
aperture allowing unimpeded transmission of thermal spectra through
said window holder.
3. The device of claim 1, wherein said window holder is made of
injection-molded plastic.
4. The device of claim 1, wherein said material is polycrystalline
float zone silicon.
5. The device of claim 1, wherein said material has a thickness of
about 0.25 millimeters.
6. The device of claim 1, further comprising a heating element
disposed upon said window.
7. The device of claim 6, wherein said heating element comprises a
grid structure.
8. The device of claim 7, wherein said grid structure comprises a
plurality of bridging sub-busses spaced apart from one another and
a plurality of heating wires spaced apart from one another, and at
least two busses disposed on opposite sides of said heating
9. The device of claim 8, wherein said sub-busses each has a width
of about 50 micrometers.
10. The device of claim 8, wherein said sub-busses are spaced apart
from one another by about 1.0 millimeters on center.
11. The device of claim 8, wherein said heating wires each has a
width of about 20 micrometers.
12. The device of claim 8, wherein said heating wires are spaced
apart from one another by about 0.5 millimeters on center.
13. The device of claim 8, wherein said busses comprise an
electrical connection whereby electrical communication is
established between said heating element and a power supply.
14. The device of claim 13, wherein said power supply is in
operative communication with a timed switching device which
intermittently supplies electrical power to said heating element
via said electrical connection.
15. A device for consistently interfacing a noninvasive optical
measurement system with a location of skin on a patient for
capturing thermal spectra therefrom, said device comprising: a
window holder having an aperture; a window covering said aperture
on said window holder, said window comprising a material of high
thermal conductivity so as to permit thermal spectra to pass
through said window; and a heating element disposed upon said
window, said heating element comprising a grid structure which
includes a plurality of bridging sub-busses, a plurality of heating
wires, and at least two busses disposed on opposite sides of said
heating element.
16. The device of claim 15, wherein said device defines a skin
contact surface configured for placement in intimate thermal
contact with said predetermined location of skin on the patient,
said device further defining a system contact surface opposite said
skin contact surface; said system contact surface being configured
for removable placement against said noninvasive optical
measurement system.
17. The device of claim 15, wherein said sub-busses each has a
width of about 50 micrometers.
18. The device of claim 15, wherein said sub-busses are spaced
apart from one another by about 1.0 millimeters on center.
19. The device of claim 15, wherein said heating wires each has a
width of about 20 micrometers.
20. The device of claim 15, wherein said heating wires are spaced
apart from one another by about 0.5 millimeters on center.
21. The device of claim 15, wherein said busses comprise an
electrical connection whereby electrical communication is
established between said heating element and a power supply.
22. The device of claim 21, wherein said power supply is in
operative communication with a timed switching device which
intermittently supplies electrical power to said heating element
via said electrical connection.
23. The device of claim 15, wherein said heating element comprises
a gold layer deposited over an alloy layer which is affixed to said
window, said gold layer and said alloy layer being formed into said
grid structure.
24. The device of claim 23, wherein said gold layer has a thickness
of about 4000 Angstroms.
25. The device of claim 23, wherein said alloy layer has a
thickness ranging between about 300 Angstroms and about 500
Angstroms.
26. The device of claim 15, wherein said window holder is made of
injection-molded plastic.
27. The device of claim 15, wherein said material is
polycrystalline float zone silicon.
28. The device of claim 15, wherein said window has a thickness of
about 0.25 millimeters.
29. A method for interfacing a noninvasive optical measurement
system with skin of a patient for capturing thermal spectra
therefrom, said method comprising: mounting a wearable window onto
the skin of the patient, said wearable window comprising a window
holder having an aperture, a window covering said aperture, said
window comprising a material of high thermal conductivity so as to
permit thermal spectra to pass through said window, and a heating
element disposed upon said window; establishing an electrical
connection between said heating element and a power source; and
placing said noninvasive optical measurement system in intimate
thermal contact with said window.
30. The method of claim 29, wherein said power source supplies
electric power to said heating element via said electrical
connection so as to apply intermittent heating to the skin of the
patient.
31. The method of claim 30, wherein said power supply is under
operational control of said noninvasive optical measurement
system.
32. The method of claim 29, wherein said mounting comprises using a
fastening strap to press said wearable window against the skin of
the patient.
33. The method of claim 32, wherein said fastening strap comprises
at least two fixed ends and at least two adjustable ends, said
fixed ends each attachable to said window holder and said
adjustable ends removably attachable to one another.
34. The method of claim 29, wherein pressure between said wearable
window and the skin of the patient causes said window holder to
grip the skin such that relative motion between the skin of the
patient and said wearable window is minimized.
35. An apparatus for use with a noninvasive optical measurement
system for capturing thermal spectra from living tissue, said
apparatus comprising: a wearable window comprising a window holder
having an aperture, a window covering said aperture, said window
comprising a material of high thermal conductivity so as to permit
thermal spectra to pass through said window, and a heating element
disposed upon said window; a first electrical connection comprising
at least two contacts molded into the surface of said window
holder, said contacts being in electrical communication with said
heating element; an interface surface of said noninvasive optical
measurement system, said interface surface including a window
aperture; and a second electrical connection comprising at least
two pins, each slidably retained within a socket of said interface
surface and spring biased in a protruded state relative to said
interface surface, said pins being in electrical communication with
a power supply; wherein pressing said wearable window against said
interface surface pushes said pins into said sockets while urging
said pins against said contacts.
36. The apparatus of claim 35, wherein said pins each corresponds
with one of said contacts so as to form a closed circuit between
said power supply and said heating element when said wearable
window is pressed against said interface surface of said
noninvasive optical measurement system.
37. The apparatus of claim 35, wherein said contacts are made of an
electrically conducting material.
38. The apparatus of claim 35, wherein said window aperture
directly corresponds with said aperture within said window
holder.
39. The apparatus of claim 35, wherein said window aperture permits
thermal spectra to pass through said interface surface.
40. The apparatus of claim 35, wherein said interface surface is
made of a semi-compliant material which grips said wearable window
so as to minimize relative motion therebetween.
41. The apparatus of claim 40, wherein said semi-compliant material
is rubber.
42. The apparatus of claim 35, wherein pressure between said
wearable window and the skin of the patient causes said window
holder to grip the skin, thereby minimizing relative motion between
the skin and the wearable window.
43. The apparatus of claim 35, wherein said power supply is in
operational communication with a timed switching device whereby
electrical power is intermittently applied to said heating
element.
44. A method for interfacing a noninvasive optical measurement
system with skin of a patient, said method comprising: providing a
wearable window comprising a window holder having an aperture, a
window covering said aperture, said window comprising a material of
high thermal conductivity so as to permit thermal spectra to pass
through said window, and a heating element disposed upon said
window; mounting said wearable window onto the skin of the patient
such that said heating element is placed into intimate contact with
the skin of the patient; positioning said wearable window on an
interface surface of said noninvasive optical measurement system
such that a window aperture within said interface surface is
centered and aligned with said aperture within the window holder;
and establishing an electrical connection between said heating
element and a power source.
45. The method of claim 44, wherein pressure between said wearable
window and the skin of the patient causes said window holder to
grip the skin, thereby minimizing relative motion between the skin
and said wearable window.
46. The method of claim 44, wherein said window aperture permits
thermal spectra to pass through said interface surface.
47. The method of claim 44, wherein said power source supplies
electrical power intermittently to said heating element.
48. The method of claim 44, wherein said electrical connection
comprises a first set of contacts on the surface of said window
holder and a second set of contacts on said interface surface, said
first set of contacts being in electrical communication with said
heating element, said second set of contacts being in electrical
communication with said power source, wherein pressing said
wearable window against said interface surface places said first
set of contacts in electrical contact with said second set of
contacts.
49. The method of claim 48, wherein said second set of contacts
comprises at least two pins each slidably retained within a socket
of said interface surface and spring biased in a protruded state
relative to said interface surface.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/310,898, filed Aug. 8, 2001, entitled
DEVICE FOR CAPTURING THERMAL SPECTRA FROM TISSUE, the entire
contents of which are hereby incorporated by reference herein and
made a part of this specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to determining analyte
concentrations within living tissue. More particularly, this
invention relates to a device for attaching a portable window to
living tissue for consistent transfer of thermal spectra to and
from the tissue.
[0004] 2. Description of the Related Art
[0005] Millions of diabetics are forced to draw blood on a daily
basis to determine their blood glucose levels. A search for a
noninvasive methodology to accurately determine blood glucose
levels has been substantially expanded in order to alleviate the
discomfort of these individuals. A significant advance in the state
of the art of noninvasive blood glucose analysis has been realized
by an apparatus taught in U.S. Pat. No. 6,198,949, titled
SOLID-STATE NON-INVASIVE INFRARED ABSORPTION SPECTROMETER FOR THE
GENERATION AND CAPTURE OF THERMAL GRADIENT SPECTRA FROM LIVING
TISSUE, issued Mar. 6, 2001, and by methodology taught in U.S. Pat.
No. 6,161,028, titled METHOD FOR DETERMINING ANALYTE CONCENTRATION
USING PERIODIC TEMPERATURE MODULATION AND PHASE DETECTION, issued
Dec. 12, 2000, as well as the methods and apparatus taught in the
Assignee's U.S. patent application Ser. No. 09/538,164, entitled
METHOD AND APPARATUS FOR DETERMINING ANALYTE CONCENTRATION USING
PHASE AND MAGNITUDE DETECTION OF A RADIATION TRANSFER FUNCTION. The
entire contents of each of the above-mentioned patents and of the
above-mentioned patent application are hereby incorporated by
reference herein.
SUMMARY OF THE INVENTION
[0006] Although the above-mentioned devices and methods have marked
a significant advance in the state of the art of noninvasive blood
constituent analysis, one possible source of error arises due to
the nature of the contact between these devices and the patient's
skin. The above-mentioned U.S. Pat. No. 6,198,949 discloses a
spectrometer for noninvasive transfer of thermal gradient spectra
to and from living tissue. The spectrometer includes an infrared
transmissive thermal mass, referred to as a thermal mass window,
for inducing a transient temperature gradient in the tissue by
means of conductive heat transfer with the tissue, and a cooling
system in operative combination with the thermal mass for the
cooling thereof. Also provided is an infrared sensor for detecting
infrared emissions from the tissue as the transient temperature
gradient progresses into the tissue, and for providing output
signals proportional to the detected infrared emissions. A data
capture system is provided for sampling the output signals received
from the infrared sensor as the transient temperature gradient
progresses into the tissue. The transient thermal gradients arising
due to the intermittent heating and cooling of the patient's skin
generate thermal spectra which yield very good measurements of the
patient's blood glucose levels.
[0007] Although the apparatus taught in the above-mentioned U.S.
Pat. No. 6,198,949 has led to a significant advance in the state of
the art of noninvasive blood glucose analysis, one possible source
of error arises due to the nature of the contact between the
thermal mass window and the patient's skin. If several separate
measurements are required, it follows that the thermal mass window
must be brought into contact with the patient's skin several times.
The problem with this is that each of such contacts tends to be
slightly different. For instance, slight differences in pressure or
skin topology may arise at the interface between the thermal mass
window and the skin; the patient may move that portion of his or
her body, for instance the arm, which is in contact with the
thermal mass window; and muscular tension may change between
measurements. Each of these factors, and perhaps others as well,
tend to complicate the already complex nature of the contact
between the skin and the thermal mass window.
[0008] A device and method are provided for use with a noninvasive
optical measurement system, such as a thermal gradient
spectrometer, for improved determination of analyte concentrations
within living tissue. In one embodiment, a wearable window is
secured to a patient's forearm thereby isolating a measurement site
on the patient's skin for determination of blood glucose levels.
The wearable window effectively replaces a window of the thermal
gradient spectrometer, and thus forms an interface between the
patient's skin and a thermal mass window of the spectrometer. When
the spectrometer must be temporarily removed from the patient's
skin, such as to allow the patient mobility, the wearable window is
left secured to the forearm so as to maintain a consistent
measurement site on the skin. When the spectrometer is later
reattached to the patient, the wearable window will again form an
interface between the spectrometer and the same location of skin as
before.
[0009] One embodiment provides a device for use with a noninvasive
optical measurement system for capturing thermal spectra from
living tissue. The device comprises a window holder and a window
connected to the window holder. The window comprises a material of
high thermal conductivity so as to permit thermal spectra to pass
through the window. The device defines a skin contact surface
configured for placement in intimate thermal contact with the skin
of a patient. The device further defines a system contact surface
opposite the skin contact surface. The system contact surface is
configured for removable placement against the noninvasive optical
measurement system.
[0010] Another embodiment provides a device for consistently
interfacing a noninvasive optical measurement system with a
location of skin on a patient for capturing thermal spectra
therefrom. The device comprises a window holder having an aperture,
a window covering the aperture on the window holder, and a heating
element disposed upon the window. The window comprises a material
of high thermal conductivity so as to permit thermal spectra to
pass through the window. The heating element comprises a grid
structure which includes a plurality of bridging sub-busses, a
plurality of heating wires, and at least two busses disposed on
opposite sides of the heating element. The busses comprise an
electrical connection whereby electrical communication is
established between the heating element and a power supply. The
power supply is in operative communication with a timed switching
device which intermittently supplies electrical power to the
heating element via the electrical connection.
[0011] In another embodiment, a method is provided for interfacing
a noninvasive optical measurement system with skin of a patient for
capturing thermal spectra therefrom. A wearable window is mounted
onto the skin of the patient. The wearable window comprises a
window holder having an aperture, a window covering the aperture
and a heating element disposed upon the window. The window
comprises a material of high thermal conductivity so as to permit
thermal spectra to pass through the window. An electrical
connection is established between the heating element and a power
source, and the noninvasive optical measurement system is placed in
intimate thermal contact with the window.
[0012] In still another embodiment, an apparatus is provided for
use with a noninvasive optical measurement system for capturing
thermal spectra from living tissue. The apparatus comprises a
wearable window which comprises a window holder having an aperture,
a window covering the aperture, and a heating element disposed upon
the window. The window comprises a material of high thermal
conductivity so as to permit thermal spectra to pass through the
window. A first electrical connection comprises at least two
contacts molded into the surface of the window holder. The contacts
are in electrical communication with the heating element. An
interface surface of the noninvasive optical measurement system
includes a window aperture. The window aperture permits thermal
spectra to pass through the interface surface. A second electrical
connection comprises at least two pins. Each pin is slidably
retained within a socket of the interface surface and spring biased
in a protruded state relative to the interface surface. The pins
are in electrical communication with a power supply. Pressing the
wearable window against the interface surface pushes the pins into
the sockets while urging the pins against the contacts.
[0013] Another embodiment provides a method for interfacing a
noninvasive optical measurement system with skin of a patient. A
wearable window is provided. The wearable window comprises a window
holder having an aperture, a window covering the aperture, and a
heating element disposed upon the window. The window comprises a
material of high thermal conductivity so as to permit thermal
spectra to pass through the window. The wearable window is mounted
onto the skin of the patient such that the heating element is
placed into intimate contact with the skin of the patient. Pressure
between the wearable window and the skin of the patient causes the
window holder to grip the skin, thereby minimizing relative motion
between the skin and the wearable window. The wearable window is
positioned on an interface surface of the noninvasive optical
measurement system such that a window aperture within the interface
surface is centered and aligned with the aperture within the window
holder. The window aperture permits thermal spectra to pass through
the interface surface. An electrical connection is established
between the heating element and a power source. The electrical
connection comprises a first set of contacts on the surface of the
window holder and a second set of contacts on the interface
surface. The first set of contacts is in electrical communication
with the heating element, and the second set of contacts is in
electrical communication with the power source. Pressing the
wearable window against the interface surface places the first set
of contacts in electrical contact with the second set of
contacts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of one embodiment of a wearable
window.
[0015] FIG. 2 is an exploded view of the wearable window of FIG.
1.
[0016] FIG. 2A is a perspective view of an embodiment of a heating
element affixed to a substrate.
[0017] FIG. 3 is a perspective view of the wearable window of FIG.
1 with an attached fastening strap.
[0018] FIG. 4 shows the wearable window of FIG. 1 strapped onto a
forearm of a patient.
[0019] FIG. 5 illustrates one embodiment of an electrical
connection established between the wearable window of FIG. 1 and an
optical measurement system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Preferred embodiments of the invention are described below.
While the description sets forth various embodiments and specific
details, it will be appreciated that the description is
illustrative only and should not to be construed in any way as
limiting the invention. Furthermore, various applications of the
invention, and modifications thereof, which may occur to those
skilled in the art, are also encompassed by the general concepts
described below.
[0021] FIG. 1 is a perspective view of one embodiment of a wearable
window 100. It is contemplated that the wearable window 100 is to
be used in conjunction with a noninvasive optical measurement
system such as, but not necessarily limited to, the apparatus
taught in the above-mentioned U.S. Pat. No. 6,198,949. This patent
discloses a noninvasive thermal gradient spectrometer comprising a
window and a, thermal mass window, wherein the window forms an
interface between a thermal mass window and a patient's skin. It is
contemplated that the wearable window 100 effectively takes the
place of the window, and thus forms the interface between the
thermal mass window and the patient's skin. It is further
contemplated that the wearable window 100 may be used in
conjunction with the noninvasive thermal gradient spectrometer in
accordance with the methodology taught in the above-mentioned U.S.
Pat. No. 6,161,028.
[0022] In the embodiment illustrated in FIG. 1, the wearable window
100 comprises a window holder 102, a substrate 104, a heating
element 105, and openings 106 to facilitate fastening the wearable
window 100 to a patient (see FIG. 4). FIG. 2 is an exploded view of
the wearable window 100, which illustrates the several elements
comprising the wearable window 100. As can be seen most clearly in
FIG. 2, the window holder 102 serves as a foundation upon which the
several elements comprising the wearable window 100 may
advantageously be affixed. Furthermore, the window holder 102
serves to facilitate attaching the wearable window 100 to a
patient's skin such that the wearable window 100 assumes intimate
contact therewith (see FIG. 4).
[0023] As used herein, "wearable window" is a broad term and is
used in its ordinary sense and refers, without limitation, to
anything capable of interfacing with a location on the body as
needed for operation of the noninvasive thermal gradient
spectrometer. Thus, it is to be noted that the invention need not
be limited to the embodiment(s) shown/described herein. The
location on the body may comprise a mechanically isolated area of
the skin or a landmark such as, by way of example, drawn, printed
or tattooed indicia. Furthermore, the wearable window 100 and/or
the substrate 104 need not be attachable to the body for prolonged
periods of time; e.g., the substrate 104 can alternatively be built
into a watch, a ring, an elbow strap which places the substrate 104
in contact with the forearm, or any other similar device which
provides a consistent measurement site on the body for operation of
the noninvasive thermal gradient spectrometer. Additional
information on noninvasive spectrometers and methods may be found
in Applicant's copending U.S. patent application No. [Attorney
Docket No. OPTIS.039C1], entitled REAGENT-LESS WHOLE-BLOOD GLUCOSE
METER, filed Jul. 19, 2002. Additional information about devices
and methods for isolating regions of the body may be found in
Applicant's copending U.S. patent application Ser. No. 09/970,021,
entitled DEVICE FOR ISOLATING REGIONS OF LIVING TISSUE, filed Oct.
2, 2001. The entire contents of each of the above-mentioned patent
applications are hereby incorporated by reference herein and made a
part of this specification.
[0024] The window holder 102 may be formed of injection-molded
plastic or other similar material such that the several elements
comprising the wearable window 100 may be affixed to the window
holder 102 with minimal movement arising therebetween. It is
further contemplated that the material comprising the window holder
102 may be such that condensation formed thereon when the window
holder 102 is exposed to cooler temperatures (below the dew point)
is substantially minimized.
[0025] As illustrated in FIG. 2, the window holder 102 further
comprises an aperture 110. The aperture 110 allows unimpeded
transmission of thermal spectra through the window holder 102 to
and from the patient's skin. Although in the embodiment of FIG. 2
the aperture 110 has a rectangular cross-sectional shape, it is
contemplated that the aperture 110 may have other cross-sectional
shapes, such as, by way of example, square, circular, diamond,
elliptical, and ovoid. It is further contemplated that different
cross-sectional shapes may advantageously be combined, thereby
forming additional cross-sectional shapes.
[0026] Disposed upon the aperture 110 of the window holder 102 is
the substrate 104. In one embodiment, the substrate 104 has a
length and a width that are somewhat greater than the length and
width of the aperture 110, thereby facilitating fastening of the
substrate 104 to the window holder 102. In another embodiment, the
substrate 104 is permanently affixed to the window holder 102. In
still another embodiment, the substrate 104 may be removably
attached to the window holder 102. In yet another embodiment, the
substrate 104 may comprise a disposable member which is attachable
to and detachable from the window holder 102.
[0027] Alternatively, the substrate 104 may be mounted within the
aperture 110 of the window holder 102 such that the upper and lower
surfaces of the substrate 104 are flush with upper and lower the
surfaces of the window holder 102. In one embodiment, the substrate
104 may be permanently affixed to the perimeter of the aperture
110. In another embodiment, the substrate 104 may be removably
attached within the aperture 110. In still another embodiment, the
substrate 104 may comprise a disposable member which is attachable
to and detachable from within the aperture 110. As will be
appreciated by those skilled in the art, the length and width of
the substrate 104 are differentially smaller than the length and
width of the aperture 110, respectively, such that the substrate
104 may be inserted within the aperture 110. As will be further
appreciated, the differentials in the lengths and widths of the
substrate 104 and the aperture 110 will depend, in large part, on
the materials used for the substrate 104 and the aperture 110, and
on the degree to which these materials expand and contract when
exposed to a particular temperature range contemplated.
[0028] In one embodiment, the substrate 104 is made of a material
having a high thermal conductivity, such as polycrystalline float
zone silicon or other similar material, such that the substrate 104
is substantially transparent to thermal spectra. In addition, the
substrate 104 may have a thickness sized such that thermal spectra
are substantially unimpeded as they transfer through the substrate
104. In the illustrated embodiment of FIGS. 1 and 2, the substrate
104 has a thickness of about 0.25 millimeters. It will be
appreciated by those of ordinary skill in the art, however, that
the material comprising the substrate 104, as well as the
dimensions thereof, may advantageously vary from the preferred
dimensions as needed.
[0029] Disposed upon the substrate 104 is the heating element 105.
The heating element 105 transfers heat to the skin of the patient,
and thus gives rise to the heating component of the aforementioned
intermittent heating and cooling of the patient's skin. Referring
to FIG. 2A, the heating element 105 is shown affixed to the
substrate 104. The heating element 105 preferably comprises a first
adhesion layer of gold or platinum (hereinafter referred to as the
"gold" layer) deposited over an alloy layer which is applied to the
substrate 104. The alloy layer comprises a material suitable for
implementation of the heating element 105, such as, by way of
example, 10/90 titanium/tungsten, titanium/platinum,
nickel/chromium, or other similar material. The gold layer
preferably has a thickness of about 4000 .ANG., and the alloy layer
preferably has a thickness ranging between about 300 .ANG. and
about 500 .ANG.. The gold layer and/or the alloy layer may be
deposited onto the substrate 104 by chemical deposition including,
but not necessarily limited to, vapor deposition, liquid
deposition, plating, laminating, casting, sintering, or other
forming or deposition methodologies well known to those or ordinary
skill in the art.
[0030] Once the heating element 105 has been deposited onto the
substrate 104, as described above, the heating element 105 is
formed into a grid structure comprising a plurality of bridging
sub-busses 120, a plurality of heating wires 122, and at least two
busses 124. The grid structure of the heating element 105 may be
formed by masking, chemical etching, photo etching, ion etching or
milling, abrasive etching, grinding or other material forming or
removal methodology well known to those of ordinary skill in the
art. In one embodiment, the gold and alloy layers comprising the
heating element 105 are etched such that the plurality of bridging
sub-busses 120 and the plurality of heating wires 122 are formed
within the heating element 105. The sub-busses 120 preferably are
about 50 .mu.m wide and spaced by about 1.0 millimeters on center.
Furthermore, the heating wires 122 preferably are about 20 .mu.m
wide and spaced by about 0.5 millimeters on center. A person of
ordinary skill in the art will recognize that the dimensions and
spacing of the bridging sub-busses 120 and the heating wires 122
may vary from the preferred dimensions as needed.
[0031] The busses 124 are in electrical communication with a
switched power supply (not shown). It is contemplated that the
power supply is further in operative communication with a timed
switching device or system control (again, not shown) which
intermittently supplies electrical power to the heating element 105
via the busses 124. This intermittent application of electrical
power may be periodic or aperiodic in nature.
[0032] As is further illustrated in FIG. 2A, the substrate 104 and
the heating element 105 initially comprise a square having sides of
a length d. In one embodiment, the length d is equal to about 12
millimeters. Following the material deposition and etching
processes discussed above, the substrate 104 and the heating
element 105 are trimmed on two opposing sides such that the two
busses 124 are formed on opposite sides of the heating element 105.
Trimming of the substrate 104 and the heating element 105 is
accomplished by cutting along the lines illustrated in FIG. 2A,
which forms a rectangle having dimensions d by d'. In one
embodiment, suitable for use with the thermal gradient spectrometer
taught in the aforementioned U.S. Pat. No. 6,198,949, d by d' are
equal to about 12 millimeters and about 10 millimeters,
respectively. However, it will be apparent to those of ordinary
skill in the art that alternative alloys, coatings, dimensions,
geometries, spacings and bus configurations may advantageously be
implemented without detracting from the invention.
[0033] It will be appreciated by a person skilled in the art that
the heating element 105 may comprise a grid structure (including
the bridging sub-busses 120, the heating wires 122, and the busses
124) which is formed as the material is being deposited onto the
surface of the substrate 104 by use of a mask or other known
techniques. It is contemplated that such an embodiment of the
heating element 105 may comprise materials, dimensions, and thermal
properties which are substantially the same as those mentioned
above.
[0034] As will be further appreciated by a person skilled in the
art, in an alternative embodiment, the heating element 105 may be
omitted from the wearable window 100. It is contemplated that with
this embodiment, the wearable window 100 comprises the window
holder 102 and the substrate 104, while an element similar in
function to the heating element 105 is provided by the thermal
gradient spectrometer or other optical measurement system with
which the wearable window 100 is intended to be used. It is further
contemplated that this embodiment of the wearable window 100 would
be particularly useful with thermal gradient spectrometers wherein
a heat source has been omitted. In such instances, heating of the
patient's skin is accomplished by allowing the skin to warm up
naturally to the ambient temperature of the surrounding
environment.
[0035] FIG. 3 is a perspective view illustrating the wearable
window 100 with one embodiment of a fastening strap 112 that may be
used in conjunction with the wearable window 100. In the
illustrated embodiment, the fastening strap 112 comprises two fixed
ends 114 and two adjustable ends 116. Each fixed end 114 passes
through one of the openings 106 and then is folded back and affixed
to the strap 112 such that the strap is attached to opposite ends
of the wearable window 100. The adjustable ends 116 are removably
attachable to one another, thereby facilitating fastening of the
wearable window 100 onto the patient (see FIG. 4), as well as
subsequent removal therefrom. The adjustable ends 116 preferably
include strips of Velcro.TM. (not shown) or other similar material
which facilitates repeated attaching and separating of the
adjustable ends 116.
[0036] A person of ordinary skill in the art will recognize that
other techniques may advantageously be utilized for placing the
wearable window 100 in contact with the patient's skin. For
example, in another embodiment the window holder 102 may include an
adhesive material which is adapted to attach the wearable window
100 to the predetermined location on the patient. With this
embodiment, the window holder 102 includes a pressure sensitive
adhesive surface which enables attaching the wearable window 100 to
the patient's skin without using the fastening strap 112.
[0037] FIG. 4 generally illustrates the use of an embodiment of the
wearable window 100, wherein the wearable window 100 is strapped to
a forearm 150 of the patient. As is illustrated, the wearable
window 100 is strapped to the forearm 150 such that the heating
element 105 is pressed against the patient's skin, while the
substrate 104 faces outward away from the skin. Pressure between
the wearable window 100 and the patient's skin causes the window
holder 102 to "grip" the skin, thereby substantially minimizing
relative motion between the skin and the wearable window 100. This
gripping of the skin provides location stability whereby the
wearable window 100 is prevented from sliding across the patient's
skin when pushed or otherwise acted on by external forces, such as
forces arising when the noninvasive optical measurement system is
coupled to and uncoupled from the wearable window 100.
[0038] As will be apparent to those of ordinary skill in the art,
the wearable window 100 covers up a region of the skin surrounding
the portion of skin from which thermal spectral readings are taken,
and prevents moisture evaporation from the covered region of skin.
This preserves and stabilizes the hydration level within the region
of skin from which readings are taken and is believed to reduce
variance and error observed in repeated measurements over time.
[0039] In operation, the heating element 105 is placed into
electrical communication with a switched power supply (not shown)
under the control of the thermal gradient spectrometer or other
optical measurement system, whereby intermittent heating is applied
to the skin. The spectrometer or other system is placed in thermal
contact with the substrate 104 such that the substrate 104 and the
heating element 105 together form an interface between the
spectrometer and the patient's skin. If, for some reason, the
spectrometer must be temporarily removed from thermal/optical
contact with the patient's skin, such as to allow the patient
mobility, the wearable window 100 may be left strapped to the
forearm 150 so as to maintain a consistent measurement site on the
skin. When the spectrometer is later reattached to or again placed
into thermal contact with the substrate 104, the wearable window
100 will again form an interface between the spectrometer and the
same location of skin as before. This substantially reduces
measurement errors arising due to variance in the location of the
contact between the spectrometer and the patient's skin.
[0040] It is to be understood that the wearable window 100 is not
restricted to use solely with the forearm 150. For example, the
wearable window 100 may advantageously be attached to the end of an
index finger. Still, one wearable window 100 may be attached to the
index finger while a second somewhat larger wearable window 100 is
at the same time attached to the forearm 150, thereby allowing for
comparison of measured values. It will be appreciated by those of
ordinary skill in the art that the wearable window 100 may
advantageously be placed in intimate contact with any location of
skin whereupon satisfactory measurements are obtained.
[0041] FIG. 5 illustrates one embodiment of an electrical
connection established between the wearable window 100 and an
optical measurement system 158, whereby electrical power may
advantageously be supplied to the heating element 105. In the
embodiment illustrated in FIG. 5, the wearable window 100 comprises
a first contact 152 and a second contact 154. The contacts 152, 154
are made of an electrically conducting material, such as gold,
silver, copper, steel, brass, or other similar material, which is
molded into the material comprising the window holder 102. It is
contemplated that the contacts 152, 154 are in electrical
communication with the heating element 105 (see FIGS. 1 through
3).
[0042] As shown, the first contact 152 directly corresponds with a
first pin 152' protruding from an interface surface 156 of the
optical measurement system 158. Similarly, the second contact 154
directly corresponds with a second pin 154' protruding from the
interface surface 156. The pins 152', 154' are slidably retained
within sockets (not shown) and are spring biased such that they are
in a neutral, protruded state relative to the interface surface
156. When the wearable window 100 is pressed against the interface
surface 156, the pins 152', 154' are pushed into the sockets while
being urged against the contacts 152, 154. It is contemplated that
the pins 152', 154' are made of an electrically conducting
material, such as gold, silver, copper, steel, brass, or other
similar material, and are in electrical communication with a
switched power supply (not shown) which resides on the optical
measurement system 158 or externally thereto. Alternatively, an
electrical connection may be established between the optical
measurement system 158 and the heating element 105 by the use of
electrical wires (not shown). It is contemplated that a "power
cord" comprising electrical wires may be passed directly from the
switched power supply to the heating element 105, thereby obviating
the pins 152', 154' and the sockets on the interface surface 156,
as well as the contacts 152, 154 on the window holder 102.
[0043] The interface surface 156 may be made of rubber or other
semi-compliant material which grips the wearable window 100,
thereby preventing relative motion between the wearable window 100
and the optical measurement system 158. The interface surface 156
includes an aperture 110' which directly corresponds with the
aperture 110 of the wearable window 100. The aperture 110' allows
thermal spectra unimpeded passage between the wearable window 100
and the optical measurement system 158.
[0044] As shown in the embodiment of FIG. 5, the interface surface
156 has a thickness which provides a thin layer of airspace between
a window (not shown) of the optical measurement system 158 and the
substrate 104. In another embodiment, however, the substrate 104
may have a thickness such that when the wearable window 100 is
pressed against the interface surface 156, a portion of the
substrate 104 extends through the aperture 110' and comes into
thermal contact with the window of the optical measurement system
158.
[0045] In operation, the wearable window 100 is fastened to the
skin of a patient and then is pressed against the interface surface
156 such that the apertures 110, 110' are centered and aligned, and
electrical communication is respectively established between the
pins 152', 154' and the contacts 152, 154. As the wearable window
100 is further pressed onto the interface surface 156, the pins
152', 154' and the contacts 152, 154 remain in electrical
communication as the pins are pushed into their respective
sockets.
[0046] Once the wearable window 100 is sufficiently pressed against
the interface surface 156, the heating element 105 is placed into
electrical communication with the above-mentioned switched power
supply (not shown), whereby intermittent heating is applied to the
skin. The optical measurement system 158 is placed in thermal
contact with the substrate 104 such that the substrate 104 and the
heating element 105 together form an interface between the optical
measurement system 158 and the patient's skin.
[0047] Although preferred embodiments of the invention have been
described in detail, certain variations and modifications will be
apparent to those skilled in the art, including embodiments that do
not provide all of the features and benefits described herein.
Accordingly, the scope of the invention is not to be limited by the
illustrations or the foregoing descriptions thereof.
* * * * *