U.S. patent application number 13/918522 was filed with the patent office on 2014-12-18 for body-mountable devices and methods for embedding a structure in a body-mountable device.
The applicant listed for this patent is Google Inc.. Invention is credited to James Etzkorn, Stephen O'Driscoll.
Application Number | 20140371560 13/918522 |
Document ID | / |
Family ID | 52019797 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140371560 |
Kind Code |
A1 |
Etzkorn; James ; et
al. |
December 18, 2014 |
Body-Mountable Devices and Methods for Embedding a Structure in a
Body-Mountable Device
Abstract
Body-mountable devices and methods for embedding a structure in
a body-mountable device are described. A body-mountable device
includes a transparent polymer and a structure embedded in the
transparent polymer. The transparent polymer defines a posterior
side and an anterior side of the body-mountable device. The
structure has an outer diameter and an inner diameter and includes
a sensor configured to detect an analyte and an antenna. The
antenna includes a plurality of conductive loops spaced apart from
each other between the outer diameter and the inner diameter.
Inventors: |
Etzkorn; James; (Mountain
View, CA) ; O'Driscoll; Stephen; (San Francisco,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Google Inc. |
Mountain View |
CA |
US |
|
|
Family ID: |
52019797 |
Appl. No.: |
13/918522 |
Filed: |
June 14, 2013 |
Current U.S.
Class: |
600/365 ;
427/2.12 |
Current CPC
Class: |
A61B 2562/12 20130101;
A61B 5/682 20130101; A61B 5/002 20130101; G02C 7/04 20130101; Y10T
156/1028 20150115; A61B 5/6821 20130101; A61B 5/14532 20130101;
A61B 5/1486 20130101 |
Class at
Publication: |
600/365 ;
427/2.12 |
International
Class: |
A61B 5/145 20060101
A61B005/145 |
Claims
1. A body-mountable device comprising: a transparent polymer,
wherein the transparent polymer defines a posterior side and an
anterior side of the body-mountable device; and a structure
embedded in the transparent polymer, wherein the structure has an
outer diameter and an inner diameter and includes a sensor
configured to detect an analyte and an antenna, wherein the antenna
includes a plurality of conductive loops spaced apart from each
other between the outer diameter and the inner diameter.
2. The body-mountable device of claim 1, wherein the body-mountable
device comprises an eye-mountable device.
3. The body-mountable device of claim 1, wherein the body-mountable
device comprises a tooth-mountable device.
4. The body-mountable device of claim 1, wherein the body-mountable
device comprises a skin-mountable device.
5. The body-mountable device of claim 1, wherein the conductive
loops are substantially concentric.
6. The body-mountable device of claim 1, wherein the plurality of
conductive loops comprises at least three conductive loops.
7. The body-mountable device of claim 1, wherein the conductive
loops are connected in parallel.
8. The body-mountable device of claim 1, wherein the conductive
loops are connected in series.
9. The body-mountable device of claim 1, wherein each conductive
loop in the plurality of conductive loops comprises a respective
metal layer disposed between respective polymer layers.
10. The body-mountable device of claim 9, wherein the metal and
polymer layers in each conductive loop are spaced apart from the
metal and polymer layers in each adjacent conductive loop in the
plurality of conductive loops.
11. The body-mountable device of claim 10, wherein the metal and
polymer layers of a particular conductive loop in the plurality of
conductive loops are spaced apart from the metal and polymer layers
of a first adjacent conductive loop in the plurality of conductive
loops by a first distance, and wherein the metal and polymer layers
of the particular conductive loop are spaced apart from the metal
and polymer layers of a second adjacent conductive loop in the
plurality of conductive loops by a second distance.
12. The body-mountable device of claim 11, wherein the first
distance varies based on a rotational orientation of the particular
conductive loop relative to the first adjacent conductive loop.
13. The body-mountable device of claim 11, wherein the second
distance varies based on a rotational orientation of the particular
conductive loop relative to the second adjacent conductive
loop.
14. The body-mountable device of claim 10, wherein the transparent
polymer extends between adjacent conductive loops in the plurality
of conductive loops.
15. The body-mountable device of claim 10, wherein the polymer
layers in each conductive loop comprise paralyene.
16. The body-mountable device of claim 1, further comprising one or
more spacers configured to maintain substantially uniform spacings
between adjacent conductive loops in the plurality of conductive
loops.
17. The body-mountable device of claim 16, wherein the one or more
spacers comprise a polymeric material.
18. The body-mountable device of claim 16, wherein the one or more
spacers comprise a metal.
19. The body-mountable device of claim 16, wherein the one or more
spacers comprise one spacer positioned on the structure
substantially opposite of the sensor.
20. The body-mountable device of claim 16, wherein the one or more
spacers are positioned on the structure at a predetermined
rotational orientation.
21. A method comprising: forming a first polymer layer, such that
the first polymer layer has a curvature, wherein the first polymer
layer defines a posterior side of a body-mountable device;
positioning a structure on the first polymer layer, wherein the
structure has an outer diameter and an inner diameter and includes
a sensor configured to detect an analyte and an antenna, and
wherein the antenna includes a plurality of conductive loops spaced
apart from each other between the outer diameter and the inner
diameter; conforming the structure positioned on the first polymer
layer to the curvature of the first polymer layer; and forming a
second polymer layer over the first polymer layer and the
structure, such that the structure is fully enclosed by the first
polymer layer and the second polymer layer, wherein the second
polymer layer defines an anterior side of the body-mountable
device.
22. The method of claim 21, wherein the body-mountable device
comprises an eye-mountable device.
23. The method of claim 21, wherein the body-mountable device
comprises a tooth-mountable device.
24. The method of claim 21, wherein the body-mountable device
comprises a skin-mountable device.
25. The method of claim 21, wherein the plurality of conductive
loops comprises at least three conductive loops.
26. The method of claim 21, the second polymer layer extends
between adjacent conductive loops in the plurality of conductive
loops.
Description
BACKGROUND
[0001] Unless otherwise indicated herein, the materials described
in this section are not prior art to the claims in this application
and are not admitted to be prior art by inclusion in this
section.
[0002] A body-mountable device may be configured to monitor
health-related information based on at least one analyte detected
in a fluid of a user wearing the body-mountable device. For
example, the body-mountable device may comprise an eye-mountable
device that may be in the form of a contact lens that includes a
sensor configured to detect the at least one analyte (e.g.,
glucose) in a tear film of a user wearing the eye-mountable device.
The body-mountable device may also be configured to monitor various
other types of health-related information.
SUMMARY
[0003] In one aspect, a body-mountable device is disclosed. An
example body-mountable device includes: a transparent polymer,
wherein the transparent polymer defines a posterior side and an
anterior side of the body-mountable device; and a structure
embedded in the transparent polymer, wherein the structure has an
outer diameter and an inner diameter and includes a sensor
configured to detect an analyte and an antenna, wherein the antenna
includes a plurality of conductive loops spaced apart from each
other between the outer diameter and the inner diameter.
[0004] In another aspect, a method involves: forming a first
polymer layer, such that the first polymer layer has a curvature,
wherein the first polymer layer defines a posterior side of a
body-mountable device; positioning a structure on the first polymer
layer, wherein the structure has an outer diameter and an inner
diameter and includes a sensor configured to detect an analyte and
an antenna, and wherein the antenna includes a plurality of
conductive loops spaced apart from each other between the outer
diameter and the inner diameter; conforming the structure
positioned on the first polymer layer to the curvature of the first
polymer layer; and forming a second polymer layer over the first
polymer layer and the structure, such that the structure is fully
enclosed by the first polymer layer and the second polymer layer,
wherein the second polymer layer defines an anterior side of the
body-mountable device.
[0005] In yet another aspect, a system is disclosed. A system
includes means for forming a first polymer layer, such that the
first polymer layer has a curvature, wherein the first polymer
layer defines a posterior side of a body-mountable device; means
for positioning a structure on the first polymer layer, wherein the
structure has an outer diameter and an inner diameter and includes
a sensor configured to detect an analyte and an antenna, and
wherein the antenna includes a plurality of conductive loops spaced
apart from each other between the outer diameter and the inner
diameter; means for conforming the structure positioned on the
first polymer layer to the curvature of the first polymer layer;
and means for forming a second polymer layer over the first polymer
layer and the structure, such that the structure is fully enclosed
by the first polymer layer and the second polymer layer, wherein
the second polymer layer defines an anterior side of the
body-mountable device.
[0006] These as well as other aspects, advantages, and
alternatives, will become apparent to those of ordinary skill in
the art by reading the following detailed description, with
reference where appropriate to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a block diagram of a system that includes an
eye-mountable device in wireless communication with an external
reader, according to an example embodiment.
[0008] FIG. 2a is a top view of a structure, according to an
example embodiment.
[0009] FIG. 2b is a side cross-section view of the structure shown
in FIG. 2a, according to an example embodiment.
[0010] FIG. 3a is a top view of an eye-mountable device, according
to an example embodiment.
[0011] FIG. 3b is a side view of the eye-mountable device shown in
FIG. 3a, according to an example embodiment.
[0012] FIG. 3c is a side cross-section view of the eye-mountable
device shown in FIG. 3a while mounted to a corneal surface of an
eye, according to an example embodiment.
[0013] FIG. 3d is a side cross-section view showing tear film
layers surrounding the surfaces of the eye-mountable device mounted
as shown in FIG. 3c, according to an example embodiment.
[0014] FIG. 4 is a top view of another structure, according to an
example embodiment.
[0015] FIG. 5 is a top view of yet another structure, according to
an example embodiment.
[0016] FIG. 6 is a flow chart illustrating a method, according to
an example embodiment.
[0017] FIG. 7a is an illustration of formation of a first polymer
layer, according to an example embodiment.
[0018] FIG. 7b is an illustration of positioning a structure on a
first polymer layer, according to an example embodiment.
[0019] FIG. 7c is an illustration of a structure positioned on a
first polymer layer, according to an example embodiment.
[0020] FIG. 7d is an illustration of conforming a structure
positioned on a first polymer layer to a curvature of the first
polymer layer, according to an example embodiment.
[0021] FIG. 7e is an illustration of formation of a second polymer
layer, according to an example embodiment.
DETAILED DESCRIPTION
[0022] The following detailed description describes various
features and functions of the disclosed systems and methods with
reference to the accompanying figures. In the figures, similar
symbols typically identify similar components, unless context
dictates otherwise. The illustrative system and method embodiments
described herein are not meant to be limiting. It will be readily
understood that certain aspects of the disclosed systems and
methods can be arranged and combined in a wide variety of different
configurations, all of which are contemplated herein.
I. INTRODUCTION
[0023] A body-mountable device may include a transparent polymer
and a structure embedded in the transparent polymer that has an
outer diameter and an inner diameter. The transparent polymer
defines a posterior side and an anterior side of the body-mountable
device. The structure includes a sensor configured to detect an
analyte and an antenna that includes a plurality of conductive
loops spaced apart from each other between the outer diameter and
the inner diameter. Beneficially, the plurality of conductive loops
can reduce buckling of the structure (e.g., one or more protrusions
from a surface of the structure) when it is bent to conform to a
curvature of the transparent polymer.
[0024] As used throughout this disclosure, the anterior side of the
body-mountable device refers to an outward-facing side of the
body-mountable device, whereas the posterior side of the
body-mountable device refers to an inward-facing side of the
body-mountable device. In particular, when the body-mountable
device comprises an eye-mountable device and the eye-mountable
device is mounted on an eye of the user, the anterior side
corresponds to a side of the eye-mountable device that is facing
outward and thus not touching the eye of the user. Further, when
the eye-mountable device is mounted on an eye of the user, the
posterior side corresponds to a side of the eye-mountable device
that is facing inward and thus touching the eye of the user.
II. EXAMPLE SYSTEMS AND DEVICES
[0025] A body-mountable device may be configured to monitor
health-related information based on at least one analyte detected
in a fluid of a user wearing the body-mountable device. An example
body-mountable device that comprises an eye-mountable device that
is configured to detect the at least one analyte in a tear film of
a user wearing the eye-mountable device will now be described in
greater detail.
[0026] FIG. 1 is a block diagram of a system 100 with an
eye-mountable device 110 in wireless communication with an external
reader 180, according to an example embodiment. The exposed regions
of the eye-mountable device 110 are made of a polymeric material
120 formed to be contact-mounted to a corneal surface of an eye. In
accordance with exemplary methods, the polymeric material 120 may
comprise a first polymer layer and a second polymer layer.
[0027] Substrate 130 is embedded in the polymeric material 120 to
provide a mounting surface for a power supply 140, a controller
150, bio-interactive electronics 160, and an antenna 170. The
bio-interactive electronics 160 are operated by the controller 150.
The power supply 140 supplies operating voltages to the controller
150 and/or the bio-interactive electronics 160. The antenna 170 is
operated by the controller 150 to communicate information to and/or
from the eye-mountable device 110. The antenna 170, the controller
150, the power supply 140, and the bio-interactive electronics 160
can all be situated on the embedded substrate 130. Because the
eye-mountable device 110 includes electronics and is configured to
be contact-mounted to an eye, it may also be referred to as an
ophthalmic electronics platform.
[0028] To facilitate contact-mounting, the polymeric material 120
can have a concave surface configured to adhere ("mount") to a
moistened corneal surface (e.g., by capillary forces with a tear
film coating the corneal surface). Additionally or alternatively,
the eye-mountable device 110 can be adhered by a vacuum force
between the corneal surface and the polymeric material due to the
concave curvature. While mounted with the concave surface against
the eye, the anterior or outward-facing surface of the polymeric
material 120 can have a convex curvature that is formed to not
interfere with eye-lid motion while the eye-mountable device 110 is
mounted to the eye. For example, the polymeric material 120 can be
a substantially transparent curved polymeric disk shaped similarly
to a contact lens.
[0029] The polymeric material 120 can include one or more
bio-compatible materials, such as those employed for use in contact
lenses or other ophthalmic applications involving direct contact
with the corneal surface. The polymeric material 120 can optionally
be formed in part from such bio-compatible materials or can include
an outer coating with such bio-compatible materials. The polymeric
material 120 can include materials configured to moisturize the
corneal surface, such as hydrogels and the like. In some instances,
the polymeric material 120 can be a deformable ("non-rigid")
material to enhance wearer comfort. In some instances, the
polymeric material 120 can be shaped to provide a predetermined,
vision-correcting optical power, such as can be provided by a
contact lens.
[0030] The substrate 130 includes one or more surfaces suitable for
mounting the bio-interactive electronics 160, the controller 150,
the power supply 140, and the antenna 170. The substrate 130 can be
employed both as a mounting platform for chip-based circuitry
(e.g., by flip-chip mounting) and/or as a platform for patterning
conductive materials (e.g., gold, platinum, palladium, titanium,
copper, aluminum, silver, metals, other conductive materials,
combinations of these, etc.) to create electrodes, interconnects,
antennae, etc. In some embodiments, substantially transparent
conductive materials (e.g., indium tin oxide) can be patterned on
the substrate 130 to form circuitry, electrodes, etc. For example,
the antenna 170 can be formed by depositing a pattern of gold or
another conductive material on the substrate 130. Similarly,
interconnects 151, 157 between the controller 150 and the
bio-interactive electronics 160, and between the controller 150 and
the antenna 170, respectively, can be formed by depositing suitable
patterns of conductive materials on the substrate 130. A
combination of resists, masks, and deposition techniques can be
employed to pattern materials on the substrate 130.
[0031] The substrate 130 can be a relatively rigid polymeric
material, such as polyethylene terephthalate ("PET"), paralyene, or
another material sufficient to structurally support the circuitry
and/or electronics within the polymeric material 120. The
eye-mountable device 110 can alternatively be arranged with a group
of unconnected substrates rather than a single substrate. For
example, the controller 150 and a bio-sensor or other
bio-interactive electronic component can be mounted to one
substrate, while the antenna 170 is mounted to another substrate
and the two can be electrically connected via the interconnects
157.
[0032] In some embodiments, the bio-interactive electronics 160
(and the substrate 130) can be positioned away from a center of the
eye-mountable device 110 and thereby avoid interference with light
transmission to the eye through the center of the eye-mountable
device 110. For example, where the eye-mountable device 110 is
shaped as a concave-curved disk, the substrate 130 can be embedded
around the periphery (e.g., near the outer circumference) of the
disk. In some embodiments, the bio-interactive electronics 160 (and
the substrate 130) can be positioned in a center region of the
eye-mountable device 110. The bio-interactive electronics 160
and/or the substrate 130 can be substantially transparent to
incoming visible light to mitigate interference with light
transmission to the eye. Moreover, in some embodiments, the
bio-interactive electronics 160 can include a pixel array 164 that
emits and/or transmits light to be perceived by the eye according
to display driver instructions. Thus, the bio-interactive
electronics 160 can optionally be positioned in the center of the
eye-mountable device so as to generate perceivable visual cues to a
wearer of the eye-mountable device 110, such as by displaying
information via the pixel array 164.
[0033] The substrate 130 can be shaped as a flattened ring with a
radial width dimension sufficient to provide a mounting platform
for the embedded electronics components. The substrate 130 can have
a thickness sufficiently small to allow the substrate 130 to be
embedded in the polymeric material 120 without influencing the
profile of the eye-mountable device 110. The substrate 130 can have
a thickness sufficiently large to provide structural stability
suitable for supporting the electronics mounted thereon. For
example, the substrate 130 can be shaped as a ring with a 1
centimeter diameter, a radial thickness of approximately 1
millimeter, and a thickness of about 50 micrometers. The substrate
130 can optionally be aligned with the curvature of the anterior
side of the eye-mountable device 110.
[0034] The power supply 140 is configured to harvest ambient energy
to power the controller 150 and the bio-interactive electronics
160. For example, a radio-frequency energy harvesting antenna 142
can capture energy from incident radio radiation. Additionally or
alternatively, solar cell(s) 144 ("photovoltaic cells") can capture
energy from incoming ultraviolet, visible, and/or infrared
radiation. Furthermore, an inertial power scavenging system (not
shown) can be included to capture energy from ambient vibrations.
The energy-harvesting antenna 142 can optionally be a dual-purpose
antenna that is also used to communicate information to the
external reader 180. That is, the functions of the antenna 170 and
the energy harvesting antenna 142 can be accomplished with the same
physical antenna.
[0035] A rectifier/regulator 146 can be used to condition the
captured energy to a stable DC supply voltage 141 that is supplied
to the controller 150. For example, the energy harvesting antenna
142 can receive incident radio frequency radiation. Varying
electrical signals on the leads of the energy harvesting antenna
142 are output to the rectifier/regulator 146. The
rectifier/regulator 146 rectifies the varying electrical signals to
a DC voltage and regulates the rectified DC voltage to a level
suitable for operating the controller 150. Additionally or
alternatively, output voltage from the solar cell(s) 144 can be
regulated to a level suitable for operating the controller 150. The
rectifier/regulator 146 can include one or more energy storage
devices arranged to mitigate high frequency variations in the
ambient energy harvesting antenna 142 and/or solar cell(s) 144. For
example, an energy storage device (e.g., capacitor, inductor, etc.)
can be connected to the output of the rectifier/regulator 146 so as
to function as a low-pass filter.
[0036] The controller 150 is turned on when the DC supply voltage
141 is provided to the controller 150, and the logic in the
controller 150 operates the bio-interactive electronics 160 and the
antenna 170. The controller 150 can include logic circuitry
configured to operate the bio-interactive electronics 160 so as to
interact with a biological environment of the eye-mountable device
110. The interaction could involve the use of one or more
components, such as an analyte bio-sensor 162, in bio-interactive
electronics 160 to obtain input from the biological environment.
Alternatively or additionally, the interaction could involve the
use of one or more components, such as the pixel array 164, to
provide an output to the biological environment.
[0037] In one example, a sensor interface module 152 can be
included for operating the analyte bio-sensor 162. The analyte
bio-sensor 162 can be, for example, an amperometric electrochemical
sensor that includes a working electrode and a reference electrode.
Application of an appropriate voltage between the working and
reference electrodes can cause an analyte to undergo
electrochemical reactions (e.g., reduction and/or oxidation
reactions) at the working electrode to generate an amperometric
current. The amperometric current can be dependent on the analyte
concentration, and thus the amount of amperometric current can
provide an indication of analyte concentration. In some
embodiments, the sensor interface module 152 can be a potentiostat
configured to apply a voltage difference between the working and
reference electrodes while measuring a current through the working
electrode.
[0038] In some embodiments, at least a portion of the
bio-interactive electronics 160, the controller 150, the power
supply, and/or the antenna 170 can be embedded in the substrate
130. And, in some embodiments, at least a portion of the
bio-interactive electronics 160 (e.g., the analyte bio-sensor 162)
can be surrounded by the substrate 130, except for a surface of the
at least a portion of the bio-interactive electronics 160 being
exposed by an opening in the substrate 130.
[0039] In some instances, a reagent can also be included to
sensitize the electrochemical sensor to desired analytes. For
example, a layer of glucose oxidase ("GOD") can be situated around
the working electrode to catalyze glucose into hydrogen peroxide
(H.sub.2O.sub.2). The hydrogen peroxide can then be oxidized at the
working electrode, which releases electrons to the working
electrode, which generates a current.
##STR00001## H.sub.2O.sub.2.fwdarw.2H.sup.++O.sub.2+2e.sup.-
[0040] The current generated by either reduction or oxidation
reactions can be approximately proportionate to the reaction rate.
Further, the reaction rate can be dependent on the rate of analyte
molecules reaching the electrochemical sensor electrodes to fuel
the reduction or oxidation reactions, either directly or
catalytically through a reagent. In a steady state, where analyte
molecules flow and/or diffuse to the electrochemical sensor
electrodes from a sampled region at approximately the same rate
that additional analyte molecules diffuse to the sampled region
from surrounding regions, the reaction rate can be approximately
proportionate to the concentration of the analyte molecules. The
current can thus provide an indication of the analyte
concentration.
[0041] The controller 150 can optionally include a display driver
module 154 for operating a pixel array 164. The pixel array 164 can
be an array of separately programmable light transmitting, light
reflecting, and/or light emitting pixels arranged in rows and
columns. The individual pixel circuits can optionally include
liquid crystal technologies, microelectromechanical technologies,
emissive diode technologies, etc. to selectively transmit, reflect,
and/or emit light according to information from the display driver
module 154. Such a pixel array 164 can also optionally include more
than one color of pixels (e.g., red, green, and blue pixels) to
render visual content in color. The display driver module 154 can
include, for example, one or more data lines providing programming
information to the separately programmed pixels in the pixel array
164 and one or more addressing lines for setting groups of pixels
to receive such programming information. Such a pixel array 164
situated on the eye can also include one or more lenses to direct
light from the pixel array to a focal plane perceivable by the
eye.
[0042] The controller 150 can also include a communication circuit
156 for sending and/or receiving information via the antenna 170.
The communication circuit 156 can optionally include one or more
oscillators, mixers, frequency injectors, etc. to modulate and/or
demodulate information on a carrier frequency to be transmitted
and/or received by the antenna 170. In some examples, the
eye-mountable device 110 is configured to indicate an output from a
bio-sensor by modulating an impedance of the antenna 170 in a
manner that is perceivable by the external reader 180. For example,
the communication circuit 156 can cause variations in the
amplitude, phase, and/or frequency of backscatter radiation from
the antenna 170, and such variations can be detected by the
external reader 180.
[0043] The controller 150 is connected to the bio-interactive
electronics 160 via interconnects 151. For example, where the
controller 150 includes logic elements implemented in an integrated
circuit to form the sensor interface module 152 and/or display
driver module 154, a patterned conductive material (e.g., gold,
platinum, palladium, titanium, copper, aluminum, silver, metals,
combinations of these, etc.) can connect a terminal on the chip to
the bio-interactive electronics 160. Similarly, the controller 150
is connected to the antenna 170 via interconnects 157.
[0044] It is noted that the block diagram shown in FIG. 1 is
described in connection with functional modules for convenience in
description. However, embodiments of the eye-mountable device 110
can be arranged with one or more of the functional modules
("sub-systems") implemented in a single chip, integrated circuit,
and/or physical feature. For example, while the rectifier/regulator
146 is illustrated in the power supply block 140, the
rectifier/regulator 146 can be implemented in a chip that also
includes the logic elements of the controller 150 and/or other
features of the embedded electronics in the eye-mountable device
110. Thus, the DC supply voltage 141 that is provided to the
controller 150 from the power supply 140 can be a supply voltage
that is provided on a chip by rectifier and/or regulator components
the same chip. That is, the functional blocks in FIG. 1 shown as
the power supply block 140 and controller block 150 need not be
implemented as separated modules. Moreover, one or more of the
functional modules described in FIG. 1 can be implemented by
separately packaged chips electrically connected to one
another.
[0045] Additionally or alternatively, the energy harvesting antenna
142 and the antenna 170 can be implemented with the same physical
antenna. For example, a loop antenna can both harvest incident
radiation for power generation and communicate information via
backscatter radiation.
[0046] The external reader 180 includes an antenna 188 (or group of
more than one antennae) to send and receive wireless signals 171 to
and from the eye-mountable device 110. The external reader 180 also
includes a computing system with a processor 186 in communication
with a memory 182. The memory 182 is a non-transitory
computer-readable medium that can include, without limitation,
magnetic disks, optical disks, organic memory, and/or any other
volatile (e.g., RAM) or non-volatile (e.g., ROM) storage system
readable by the processor 186. The memory 182 can include a data
storage 183 to store indications of data substrates, such as sensor
readings (e.g., from the analyte bio-sensor 162), program settings
(e.g., to adjust behavior of the eye-mountable device 110 and/or
external reader 180), etc. The memory can also include program
instructions 184 for execution by the processor 186 to cause the
external reader to perform processes specified by the program
instructions 184. For example, the program instructions 184 can
cause external reader 180 to provide a user interface that allows
for retrieving information communicated from the eye-mountable
device 110 (e.g., sensor outputs from the analyte bio-sensor 162).
The external reader 180 can also include one or more hardware
components for operating the antenna 188 to send and receive the
wireless signals 171 to and from the eye-mountable device 110. For
example, oscillators, frequency injectors, encoders, decoders,
amplifiers, filters, etc. can drive the antenna 188 according to
instructions from the processor 186.
[0047] The external reader 180 can be a smart phone, digital
assistant, or other portable computing device with wireless
connectivity sufficient to provide the wireless communication link
171. The external reader 180 can also be implemented as an antenna
module that can be plugged into a portable computing device, such
as in an example where the communication link 171 operates at
carrier frequencies not commonly employed in portable computing
devices. In some instances, the external reader 180 is a
special-purpose device configured to be worn relatively near a
wearer's eye to allow the wireless communication link 171 to
operate with a low power budget. For example, the external reader
180 can be integrated in a piece of jewelry such as a necklace,
earing, etc. or integrated in an article of clothing worn near the
head, such as a hat, headband, etc.
[0048] In an example where the eye-mountable device 110 includes an
analyte bio-sensor 162, the system 100 can be operated to monitor
the analyte concentration in tear film on the surface of the eye.
Thus, the eye-mountable device 110 can be configured as a platform
for an ophthalmic analyte bio-sensor. The tear film is an aqueous
layer secreted from the lacrimal gland to coat the eye. The tear
film is in contact with the blood supply through capillaries in the
substrate of the eye and includes many biomarkers found in blood
that are analyzed to characterize a person's health condition(s).
For example, the tear film includes glucose, calcium, sodium,
cholesterol, potassium, other biomarkers, etc. The biomarker
concentrations in the tear film can be systematically different
than the corresponding concentrations of the biomarkers in the
blood, but a relationship between the two concentration levels can
be established to map tear film biomarker concentration values to
blood concentration levels. For example, the tear film
concentration of glucose can be established (e.g., empirically
determined) to be approximately one tenth the corresponding blood
glucose concentration. Thus, measuring tear film analyte
concentration levels provides a non-invasive technique for
monitoring biomarker levels in comparison to blood sampling
techniques performed by lancing a volume of blood to be analyzed
outside a person's body. Moreover, the ophthalmic analyte
bio-sensor platform disclosed here can be operated substantially
continuously to enable real time monitoring of analyte
concentrations.
[0049] To perform a reading with the system 100 configured as a
tear film analyte monitor, the external reader 180 can emit radio
frequency radiation 171 that is harvested to power the
eye-mountable device 110 via the power supply 140. Radio frequency
electrical signals captured by the energy harvesting antenna 142
(and/or the antenna 170) are rectified and/or regulated in the
rectifier/regulator 146 and a regulated DC supply voltage 647 is
provided to the controller 150. The radio frequency radiation 171
thus turns on the electronic components within the eye-mountable
device 110. Once turned on, the controller 150 operates the analyte
bio-sensor 162 to measure an analyte concentration level. For
example, the sensor interface module 152 can apply a voltage
between a working electrode and a reference electrode in the
analyte bio-sensor 162 sufficient to cause the analyte to undergo
an electrochemical reaction at the working electrode. The current
through the working electrode can be measured to provide the sensor
output indicative of the analyte concentration. The controller 150
can operate the antenna 170 to communicate the sensor results back
to the external reader 180 (e.g., via the communication circuit
156). The sensor result can be communicated by, for example,
modulating an impedance of the antenna 170 such that the modulation
in impedance is detected by the external reader 180. The modulation
in antenna impedance can be detected by, for example, backscatter
radiation from the antenna 170.
[0050] In some embodiments, the system 100 can operate to
non-continuously ("intermittently") supply energy to the
eye-mountable device 110 to power the on-board controller 150 and
the bio-interactive electronics 160. For example, radio frequency
radiation 171 can be supplied to power the eye-mountable device 110
long enough to carry out a tear film analyte concentration
measurement and communicate the results. For example, the supplied
radio frequency radiation can provide sufficient power to charge
two electrodes to a potential sufficient to induce electrochemical
reactions, measure the resulting amperometric current, and modulate
the antenna impedance to adjust the backscatter radiation in a
manner indicative of the measured current. In such an example, the
supplied radio frequency radiation 171 can be considered an
interrogation signal from the external reader 180 to the
eye-mountable device 110 to request a measurement. By periodically
interrogating the eye-mountable device 110 (e.g., by supplying
radio frequency radiation 171 to temporarily turn the device on)
and storing the sensor results (e.g., via the data storage 183),
the external reader 180 can accumulate a set of analyte
concentration measurements over time without continuously powering
the eye-mountable device 110.
[0051] FIG. 2a is a top view of a structure 230, according to an
example embodiment. In particular, the structure 230 has an outer
diameter 232 and an inner diameter 234 and includes electronics
240, electronics 250, a sensor 260, and an antenna 270 disposed
thereon. The structure 230 may take the form of or be similar in
form to the substrate 130.
[0052] The structure 230 can have various sizes. For instance, the
size of the structure 230 may depend on which analyte an
eye-mountable device is configured to detect. In an example, the
structure 230 has a maximum height of approximately 50 between 150
micrometers. Of course, other maximum heights of the structure 230
are possible as well.
[0053] In an example, the structure 230 has a height dimension of
at least 50 micrometers. In other words, at some point of the
structure 230, the height of the structure 230 may be at least 50
micrometers. In an example, this height dimension may correspond to
a maximum height of the structure 230. In accordance with the
present disclosure, the maximum height of the structure 230
corresponds to the height of the structure 230 at its highest
point. For instance, in the example where the structure 230
comprises the sensor 260 and the electronics 250, the height of the
structure 230 may vary (and thus the structure 230 may have various
height dimensions). For example, the height of the structure 230
may be higher at a point where the electronics 250 is mounted on
the structure 230, whereas the height may be lower at a point where
there is no chip on the structure 230. In such an example, the
maximum height may correspond to the point where the electronics
250 is mounted on the structure 230.
[0054] The outer diameter 232 and the inner diameter 234 could take
various different forms in various different embodiments. In some
embodiments, the outer diameter can have a length between 12.5 and
15 millimeters. Moreover, in some embodiments, the inner diameter
can have a length greater than 8 millimeters. And other lengths of
the outer diameter 232 and/or inner diameter 234 are possible as
well.
[0055] The electronics 240 and 250 could be configured in a variety
of ways. For example, the electronics 240 and/or the electronics
250 may be configured to operate the sensor 260 and the antenna
270. And, in such an example, the electronics 240 and/or the
electronics 250 may be configured for wireless communication with
an external reader, such as the external reader 180. In some
embodiments, the electronics 240 and the electronics 250 may
provide a bias voltage for the sensor 260 and adjust backscattered
radio frequency (RF) that is proportional to a current that is
passing through the sensor 260.
[0056] The electronics 240 and the electronics 250 could take
various different forms in various different embodiments. In some
embodiments, the electronics 240 and/or the electronics 250 can
comprise a chip including one or more logical elements. The
electronics 240 and/or the electronics 250 may take the form of or
be similar in form to the controller 150.
[0057] The sensor 260 is configured to detect one or more analytes.
The sensor 260 could take various different forms in various
different embodiments. In some embodiments, the sensor 260 can
comprise a pair of electrodes, such as a working electrode and a
reference electrode. The sensor 260 may take the form of or be
similar in form to the analyte bio-sensor 162.
[0058] The antenna 270 is configured for communications and/or
harvesting energy as described herein. The antenna 270 includes a
plurality of conductive loops 272 spaced apart from each other
between the outer diameter 232 and the inner diameter 234. In the
illustrated example, the plurality of conductive loops 272 includes
three conductive loops 272A, 272B, and 272C. However, in other
examples, a plurality of conductive loops may include more than
three conductive loops, such as five conductive loops, nine
conductive loops, etc.
[0059] As shown in FIG. 2a, the conductive loops 272A, 272B, and
272C are connected in parallel. With this arrangement, each of the
conductive loops in the plurality of conductive loops 272 is
electrically connected to the electronics 240, the electronics 250,
and the sensor 260 via a first connection 274 and a second
connection 276. And the electronics 240, the electronics 250, and
the sensor 260 are electrically connected via the first connection
274 and the second connection 276. The first connection 274 and the
second connection 276 may take the form of or be similar in form to
the interconnects 151 and 157. Moreover, as shown in FIG. 2a, the
conductive loops 272A, 272B, and 272C are substantially concentric.
The term "substantially concentric," as used in this disclosure,
refers to exactly concentric and/or one or more deviations from
exactly concentric that do not significantly impact embedding a
structure in a body-mountable device as described herein.
[0060] And as shown in FIG. 2a, the conductive loops 272A, 272B,
and 272C are spaced apart from each other between the outer
diameter 232 and the inner diameter 234. In an example, the
conductive loops 272A, 272B, and 272C can be spaced apart from
adjacent conductive loops by a distance between 100 to 200
micrometers. Other distances are possible as well.
[0061] In some embodiments, one of the conductive loops 272A, 272B,
and 272C can have a width of 333 micrometers. Other widths of the
conductive loops 272A, 272B, and 272C are possible as well.
Moreover, in some embodiments, the conductive loops 272A, 272B, and
272C can each have the same width (e.g., the conductive loops 272A,
272B, and 272C can each have a width of 333 micrometers). However,
in some embodiments, the conductive loops 272A, 272B, and 272C
might not have the same width.
[0062] Each conductive loop in the plurality of conductive loops
272 can comprise a respective metal layer disposed between
respective polymer layers. With this arrangement, the polymer
layers might block moisture from the metal layer. FIG. 2b is a side
cross-section view of the structure shown in FIG. 2a, according to
an example embodiment. As shown in FIG. 2b, the conductive loop
272A comprises a metal layer 280 disposed between polymer layers
282A and 282B. The respective metal layers of the conductive loops
272B and 272C may take the form of or be similar in form to the to
the metal layer 280, and the respective polymer layers of the
conductive loops 272B and 272C may take the form of or be similar
in form to the polymer layers 282A and 282B.
[0063] In some embodiments, the metal layer 280 can comprise gold
or another conductive material that can be deposited on the
structure 230, such as platinum, palladium, titanium, carbon,
aluminum, copper, silver, and/or silver-chloride. And in at least
one such embodiment, the metal layer 280 can have a thickness
between 5 and 30 micrometers. Other thicknesses of the metal layer
280 are possible as well. In an example, the metal layer 280 can be
formed by a process that includes electroplating.
[0064] Moreover, in some embodiments, the polymer layers 282A and
282B can comprise a relatively rigid transparent polymer, such as
PET or paralyene. And in at least one such embodiment, the polymer
layers 282A and 282B can have a thickness between 10 and 50
micrometers, such as 15 micrometers. Other thicknesses of the
polymer layers 282A and 282B are possible as well. In an example,
the polymer layers 282A and 282B can be formed by a process that
includes chemical vapor deposition.
[0065] In an example, the plurality of conductive loops 272 can be
formed by a process that includes etching a portion of a metal
layer disposed between polymer layers with an inductively coupled
plasma, such as an oxygen plasma.
[0066] FIG. 3a is a top view of an eye-mountable electronic device
310. FIG. 3b is a side view of the eye-mountable electronic device
310 shown in FIG. 3a. It is noted that relative dimensions in FIGS.
3a and 3b are not necessarily to scale, but have been rendered for
purposes of explanation only in describing the arrangement of the
eye-mountable electronic device 310. The eye-mountable device 310
is formed of a transparent polymer 320 shaped as a curved disk. The
transparent polymer 320 can be a substantially transparent material
to allow incident light to be transmitted to the eye while the
eye-mountable device 310 is mounted to the eye. The transparent
polymer 320 can be a bio-compatible material similar to those
employed to form vision correction and/or cosmetic contact lenses
in optometry, such as PET, polymethyl methacrylate ("PMMA"),
silicone hydrogels, combinations of these, etc. The transparent
polymer 320 could take the form of or be similar in form to the
polymeric material 120.
[0067] The transparent polymer 320 can be formed with one side
having a posterior side 326 (i.e., concave surface) suitable to fit
over a corneal surface of an eye. The opposing side of the disk can
have anterior side 324 (i.e., convex surface) that does not
interfere with eyelid motion while the eye-mountable device 310 is
mounted to the eye. A circular outer side edge 328 connects the
posterior side 326 and anterior side 324.
[0068] The eye-mountable device 310 can have dimensions similar to
a vision correction and/or cosmetic contact lenses, such as a
diameter of approximately 1 centimeter, and a thickness of about
0.1 to about 0.5 millimeters. However, the diameter and thickness
values are provided for explanatory purposes only. In some
embodiments, the dimensions of the eye-mountable device 310 can be
selected according to the size and/or shape of the corneal surface
and/or the scleral surface of the wearer's eye.
[0069] While the eye-mountable device 310 is mounted in an eye, the
anterior side 324 faces outward to the ambient environment while
the posterior side 326 faces inward, toward the corneal surface.
The anterior side 324 can therefore be considered an outer, top
surface of the eye-mountable device 310 whereas the posterior side
326 can be considered an inner, bottom surface. The "top" view
shown in FIG. 3a is facing the anterior side 324.
[0070] The structure 330 is embedded in the transparent polymer
320. The substrate 330 can be embedded to be situated along an
outer periphery 322 of the transparent polymer 320, away from a
center region 321. The structure 330 does not interfere with vision
because it is too close to the eye to be in focus and is positioned
away from the center region 321 where incident light is transmitted
to the light-sensing portions of the eye. The structure 330 can
take the form or be similar in form to the substrate 130 and/or the
structure 230.
[0071] The structure 330 has an outer diameter 332 and an inner
diameter 334 and includes electronics 340, electronics 350, a
sensor 360, and an antenna 370 disposed thereon. The outer diameter
332 may take the form of or be similar in form to the outer
diameter 232, the inner diameter 334 may take the form of or be
similar in form to the inner diameter 234, the electronics 340 may
take the form of or be similar in form to the controller 150 and/or
the electronics 240, the electronics 350 may take the form or be
similar in form to the controller 150 and/or the electronics 250,
and the sensor 360 may take the form or be similar in form to the
bio-analyte sensor 162 and/or the sensor 260.
[0072] The antenna 370 is configured for communications and/or
harvesting energy, like the antenna 270 is configured for
communications and/or harvesting energy. The antenna 370 includes a
plurality of conductive loops 372 spaced apart from each other
between the outer diameter 332 and the inner diameter 334. In the
illustrated example, the plurality of conductive loops 372 includes
three conductive loops 372A, 372B, and 372C. However, in other
examples, a plurality of conductive loops may include more than
three conductive loops, such as five conductive loops, nine
conductive loops, etc. When the structure 330 is embedded in the
transparent polymer 320, the conductive loops 372A, 372B, and 372C
may move relative to each other.
[0073] The conductive loops 372A, 372B, and 372C can have an
arrangement similar to an arrangement of the conductive loops 272A,
272B, and 272C. As shown in FIGS. 3a and 3b, the conductive loops
372A, 372B, and 272C are connected in parallel. With this
arrangement, each of the conductive loops in the plurality of
conductive loops 372 is electrically connected to the electronics
340, the electronics 350, and the sensor 360 via a first connection
374 and a second connection 376. And the electronics 340, the
electronics 350, and the sensor 360 are electrically connected via
the first connection 374 and the second connection 376. The first
connection 374 and the second connection 376 may take the form of
or be similar in form to the first connection 274 and the second
connection 276 and/or the interconnects 151 and 157. Moreover, as
shown in FIGS. 3a and 3b, the conductive loops 372A, 372B, and 372C
are substantially concentric. And as shown in FIGS. 3a and 3b, the
conductive loops 372A, 372B, and 372C are spaced apart from each
other between the outer diameter 332 and the inner diameter
334.
[0074] The conductive loops 372A, 372B, and 372C may have a width
that is the same or similar to a width of the conductive loops
272A, 272B, and 272C. Moreover, each of the conductive loops in the
plurality of conductive loops 372 can comprise a respective metal
layer disposed between respective polymer layers, like the
conductive loops in the plurality of conductive loops 272 comprise
a respective metal layer disposed between respective polymer
layers. And the plurality of conductive loops 372 can be formed
like the plurality of conductive loops 272 is formed.
[0075] In the illustrated example, the metal and polymer layers in
each conductive loop in the plurality of conductive loops 372 are
spaced apart from the metal and polymer layers in each adjacent
conductive loop in the in the plurality of conductive loops 372. In
some embodiments, the transparent polymer 320 can extend between
adjacent conductive loops (e.g., the conductive loop 372A and the
conductive loop 372B and/or the conductive loop 372B and the
conductive loop 372C) in the plurality of conductive loops 372.
[0076] Moreover, in the illustrated example, the metal and polymer
layers of conductive loop 372B are spaced apart from the metal and
polymer layers of adjacent conductive loop 372A by a first distance
394, and the metal and polymer layers of conductive loop 372B are
spaced apart from the metal and polymer layers of adjacent
conductive loop 372C by a second distance 396. In an example, the
first distance 394 and the second distance 396 can be between 100
to 200 micrometers. Other distances are possible as well.
[0077] The first distance 394 could be a different value than the
second distance 396. In some embodiments, the first distance 394
can be greater (or less) than the second distance 396. And the
first distance 394 and/or the second distance 396 could vary. In
some embodiments, the first distance 394 can vary based on a
rotational orientation of the conductive loop 372B relative to the
conductive loop 372A and/or the conductive loop 372C. Moreover, in
some embodiments, the second distance 396 can vary based on a
rotational orientation of the conductive loop 372B relative to the
conductive loop 372C and/or the conductive loop 372A.
[0078] FIG. 3c is a side cross-section view of the eye-mountable
310 while mounted to a corneal surface 384 of an eye 380, according
to an example embodiment. FIG. 3d is a close-in side cross-section
view enhanced to show tear film layers 390, 392 surrounding exposed
surfaces 324, 326 of the eye-mountable device 310, according to an
example embodiment. It is noted that relative dimensions in FIGS.
3c and 3d are not necessarily to scale, but have been rendered for
purposes of explanation only in describing the arrangement of the
eye-mountable electronic device 310. For example, the total
thickness of the eye-mountable device 310 can be about 200
micrometers, while the thickness of the tear film layers 390, 392
can each be about 10 micrometers, although this ratio may not be
reflected in the drawings. Some aspects are exaggerated to allow
for illustration and facilitate explanation.
[0079] The eye 380 includes a cornea 382 that is covered by
bringing the upper eyelid 386 and lower eyelid 388 together over
the top of the eye 380. Incident light is received by the eye 380
through the cornea 382, where light is optically directed to
light-sensing elements of the eye 380 (e.g., rods and cones, etc.)
to stimulate visual perception. The motion of the eyelids 386, 388
distributes a tear film across the exposed corneal surface 384 of
the eye 380. The tear film is an aqueous solution secreted by the
lacrimal gland to protect and lubricate the eye 380. When the
eye-mountable device 310 is mounted in the eye 380, the tear film
coats both the anterior and posterior sides 324, 326 with an inner
layer 390 (along the posterior side 326) and an outer layer 392
(along the anterior side 324). The tear film layers 390, 392 can be
about 10 micrometers in thickness and together account for about 10
microliters.
[0080] The tear film layers 390, 392 are distributed across the
corneal surface 384 and/or the posterior side 324 by motion of the
eyelids 386, 388. For example, the eyelids 386, 388 raise and
lower, respectively, to spread a small volume of tear film across
the corneal surface 384 and/or the anterior side 324 of the
eye-mountable device 310. The tear film layer 390 on the corneal
surface 384 also facilitates mounting the eye-mountable device 310
by capillary forces between the anterior side 326 and the corneal
surface 384. In some embodiments, the eye-mountable device 310 can
also be held over the eye in part by vacuum forces against the
corneal surface 384 due to the concave curvature of the eye-facing
anterior side 326.
[0081] In some embodiments, a polymer layer defining the anterior
side 326 may be greater than 50 micrometers thick, whereas a
polymer layer defining the posterior side 324 may be less than 150
micrometers. Thus, when the sensor 360 is mounted on an
outward-facing surface 335 (as shown in FIG. 3d) the sensor 360 may
be at least 50 micrometers away from the anterior side 324 and may
be a greater distance away from the posterior side 326. However, in
other examples, the sensor 360 may be mounted on an inward-facing
surface 333 of the structure 330 such that the sensor 360 is facing
the posterior side 326. The sensor 360 could also be positioned
closer to the anterior side 324 than the posterior side 326. With
this arrangement, the sensor 360 can receive analyte concentrations
in the tear film 392 via a channel 373. In some examples, analyte
concentrations in the tear film 390 and/or 392 may diffuse through
the transparent polymer 320 to the sensor 360. As a result, the
eye-mountable device 310 might not include the channel 373.
[0082] While the body-mountable device has been described as
comprising the eye-mountable device 110 and/or the eye-mountable
device 310, the body-mountable device could comprise other
mountable devices that are mounted on or in other portions of the
human body.
[0083] For example, in some embodiments, the body-mountable device
may comprise a tooth-mountable device. In some embodiments, the
tooth-mountable device may take the form of or be similar in form
to the eye-mountable device 110 and/or the eye-mountable device
310. For instance, the tooth-mountable device could include a
polymeric material or a transparent polymer that is the same or
similar to any of the polymeric materials or transparent polymers
described herein and a substrate or a structure that is the same or
similar to any of the substrates or structures described herein.
With such an arrangement, the tooth-mountable device may be
configured to detect at least one analyte in a fluid (e.g., saliva)
of a user wearing the tooth-mountable device.
[0084] Moreover, in some embodiments, the body-mountable device may
comprise a skin-mountable device. In some embodiments, the
skin-mountable device may take the form of or be similar in form to
the eye-mountable device 110 and/or the eye-mountable device 310.
For instance, the skin-mountable device could include a polymeric
material or a transparent polymer that is the same or similar to
any of the polymeric materials or transparent polymers described
herein and a substrate or a structure that is the same or similar
to any of the substrates or structures described herein. With such
an arrangement, the skin-mountable device may be configured to
detect at least one analyte in a fluid (e.g., perspiration, blood,
etc.) of a user wearing the skin-mountable device.
[0085] Further, some embodiments may include privacy controls which
may be automatically implemented or controlled by the wearer of a
body-mountable device. For example, where a wearer's collected
physiological parameter data and health state data are uploaded to
a cloud computing network for trend analysis by a clinician, the
data may be treated in one or more ways before it is stored or
used, so that personally identifiable information is removed. For
example, a user's identity may be treated so that no personally
identifiable information can be determined for the user, or a
user's geographic location may be generalized where location
information is obtained (such as to a city, ZIP code, or state
level), so that a particular location of a user cannot be
determined.
[0086] Additionally or alternatively, wearers of a body-mountable
device may be provided with an opportunity to control whether or
how the device collects information about the wearer (e.g.,
information about a user's medical history, social actions or
activities, profession, a user's preferences, or a user's current
location), or to control how such information may be used. Thus,
the wearer may have control over how information is collected about
him or her and used by a clinician or physician or other user of
the data. For example, a wearer may elect that data, such as health
state and physiological parameters, collected from his or her
device may only be used for generating an individual baseline and
recommendations in response to collection and comparison of his or
her own data and may not be used in generating a population
baseline or for use in population correlation studies.
[0087] FIG. 4 is a top view of a structure 430, according to an
example embodiment. In particular, the structure 430 includes a
spacer 478 configured to maintain substantially uniform spacings
between adjacent conductive loops in a plurality of conductive
loops 472. The term "substantially uniform," as used in this
disclosure, refers to exactly uniform and/or one or more deviations
from exactly uniform that do not significantly impact embedding an
structure in a body-mountable device as described herein.
[0088] More specifically, the structure 430 has an outer diameter
432 and an inner diameter 434 and includes electronics 440,
electronics 450, a sensor 460, and an antenna 470 disposed thereon.
The outer diameter 432 may take the form of or be similar in form
to the outer diameter 232 and/or the outer diameter 332; the inner
diameter 434 may take the form of or be similar in form to the
inner diameter 234 and/or the inner diameter 334; the electronics
440 may take the form of or be similar in form to the controller
150, the electronics 240, and/or the electronics 340, the
electronics 450 may take the form or be similar in form to the
controller 150, the electronics 250, and/or the electronics 350;
and the sensor 460 may take the form or be similar in form to the
bio-analyte sensor 162, the sensor 260, and/or the sensor 360.
[0089] The antenna 470 is configured for communications and/or
harvesting energy, like the antenna 270 and the antenna 370 are
configured for communications and/or harvesting energy. As noted,
the antenna 470 includes the plurality of conductive loops 472. The
plurality of conductive loops 472 is spaced apart from each other
between the outer diameter 432 and the inner diameter 434. In the
illustrated example, the plurality of conductive loops 472 includes
three conductive loops 472A, 472B, and 472C. However, in other
examples, a plurality of conductive loops may include more than
three conductive loops, such as five conductive loops, nine
conductive loops, etc.
[0090] The conductive loops 472A, 472B, and 472C can have an
arrangement similar to an arrangement of the conductive loops 272A,
272B, and 272C and/or the conductive loops 372A, 372B, and 372C. As
shown in FIG. 4, the conductive loops 472A, 472B, and 472C are
connected in parallel. With this arrangement, each of the
conductive loops in the plurality of conductive loops 472 is
electrically connected to the electronics 440, the electronics 450,
and the sensor 460 via a first connection 474 and a second
connection 476. And the electronics 440, the electronics 450, and
the sensor 460 are electrically connected via the first connection
474 and the second connection 476. The first connection 474 and the
second connection 476 may take the form of or be similar in form to
the interconnects 151 and 157, the first connection 274 and the
second connection 276, and/or the first connection 374 and the
second connection 376.
[0091] Moreover, as shown in FIG. 4, the conductive loops 472A,
472B, and 472C are substantially concentric. And as shown in FIG.
4, the conductive loops 472A, 472B, and 472C are spaced apart from
each other between the outer diameter 432 and the inner diameter
434. In an example, the conductive loops 472A, 472B, and 472C can
be spaced apart from adjacent conductive loops by a distance
between 100 to 200 micrometers. Other distances are possible as
well.
[0092] The conductive loops 472A, 472B, and 472C may have a width
that is the same or similar to a width of the conductive loops
272A, 272B, and 272C and/or the conductive loops 372A, 372B, and
372C. Moreover, each of the conductive loops in the plurality of
conductive loops 472 can comprise a respective metal layer disposed
between respective polymer layers, like the conductive loops in the
plurality of conductive loops 272 comprise a respective metal layer
disposed between respective polymer layers. And the plurality of
conductive loops 472 can be formed like the plurality of conductive
loops 272 and/or the plurality of conductive loops 372 is
formed.
[0093] The structure 430 may be embedded in a transparent polymer,
such as the transparent polymer 320. For instance, when the
structure 430 is embedded in the transparent polymer, when each of
the conductive loops in the plurality of conductive loops 472
comprise a respective metal layer disposed between respective
polymer layers, the metal and polymer layers in each conductive
loop in the plurality of conductive loops 472 can be spaced apart
from the metal and polymer layers in each adjacent conductive loop
in the plurality of conductive loops 472. And the transparent
polymer can extend between adjacent conductive loops in the
plurality of conductive loops 472.
[0094] As noted, the structure 430 includes the spacer 478. When
the structure 430 is embedded in the transparent polymer the
conductive loops 472A, 472B, and 472C may not move relative to each
other based on the spacer 478.
[0095] As shown in FIG. 4, the spacer 478 is connected to the
conductive loops 472A, 472B, and 472C and is located on the
structure 430 substantially opposite of the sensor 260. Other
locations of the spacer 478 on the structure 430 are possible as
well. For instance, the spacer 478 could be located on the
structure 430 at a predetermined rotational orientation, such as 30
degrees, 45 degrees, 60 degrees, 90 degrees, etc. The term
"substantially opposite," as used in this disclosure, refers to
exactly opposite (e.g., a rotational orientation of 180 degrees) or
one or more deviations from exactly opposite that do not
significantly impact embedding a structure in a body-mountable
device as described herein.
[0096] The spacer 478 could take various different forms in various
different embodiments. For example, in some embodiments, the spacer
478 can have a width between 50 and 300 micrometers. Other widths
of the spacer 478 are possible as well. Moreover, in some
embodiments, the spacer 478 can comprise a metal, such as gold,
platinum, palladium, titanium, aluminum, copper, and/or silver. In
some examples, the spacer 478 can comprise the same metal as the
respective metal layers of the conductive loops 472A, 472B, and
472C. However, in other examples, the spacer 478 can comprise a
different metal than the respective metal layers of the conductive
loops 472A, 472B, and 472C. In an example, the spacer 478 can be
formed by a process that includes electroplating.
[0097] Furthermore, in some embodiments, the spacer 478 can
comprise a polymeric material, such as PET or paralyene. In some
examples, the spacer 478 can comprise the same polymeric material
as the respective polymer layers of the conductive loops 472A,
472B, and 472C. However, in other examples, the spacer 478 can
comprise a different polymeric material than the respective polymer
layers of the conductive loops 472A, 472B, and 472C. In an example,
the spacer 478 can be formed by a process that includes chemical
vapor deposition.
[0098] And in some embodiments, the spacer 478 can comprise a metal
layer disposed between polymer layers, like the respective metal
layers disposed between the respective polymer layers of the
conductive loops 472A, 472B, and 472C.
[0099] In an example, the spacer 478 is formed by a process that
includes etching a portion of a metal and/or a polymeric material
with an inductively coupled plasma, such as an oxygen plasma.
[0100] In the illustrated example, the structure 430 includes one
spacer, the spacer 478. However, in other examples, a structure may
include more than one spacer, such as two spacers, three spacers,
four spacers, etc. For instance, a structure could include one or
more spacers configured to maintain substantially uniform spacings
between adjacent conductive loops in a plurality of conductive
loops. And each spacer in the one or more spacers could be located
on the structure in a predetermined rotational orientation, such as
30 degrees, 45 degrees, 60 degrees, 90 degrees, etc. Each of the
spacers in the one or more spacers could take the form or be
similar in form to the spacer 478.
[0101] FIG. 5 is a top view of a structure 530, according to an
example embodiment. In particular, the structure 530 includes an
antenna 570 that includes a plurality of conductive loops 572 that
includes three conductive loops 572A, 572B, and 572C. As shown in
FIG. 5, the conductive loops 572A, 572B, and 572C are connected in
series.
[0102] More specifically, the structure 530 has an outer diameter
532, and an inner diameter 534. The outer diameter 532 may take the
form of or be similar in form to the outer diameter 232, the outer
diameter 332, and/or the outer diameter 432; and the inner diameter
434 may take the form of or be similar in form to the inner
diameter 234, the inner diameter 334, and or the inner diameter
434.
[0103] As noted, the structure 530 includes the antenna 570. The
antenna 570 is configured for communications and/or harvesting
energy, like the antenna 270, the antenna 370, and the antenna 470
are configured for communications and/or harvesting energy. The
antenna 570 includes the plurality of conductive loops 572 spaced
apart from each other between the outer diameter 532 and the inner
diameter 534. In the illustrated example, the plurality of
conductive loops 572 includes the conductive loops 572A, 572B, and
572C. However, in other examples, a plurality of conductive loops
may include more than three conductive loops, such as five
conductive loops, nine conductive loops, etc.
[0104] As noted, the conductive loops 572A, 572B, and 572C are
connected in series. With this arrangement, the conductive loop
572A is electrically connected to an electrical component 555 via a
first connection 574 and the conductive loop 572C is electrically
connected to the electrical component 555 via a second connection
576. The electrical component 555 could include electronics (e.g.,
the controller 150, the electronics 240, the electronics 250, the
electronics 340, the electronics 350, the electronics 440, and/or
the electronics 450) and/or a sensor (e.g., the analyte bio-sensor
162, the sensor 260, the sensor 360, and/or the sensor 460). When
the electrical component 555 includes more than one component, the
more than one component could be arranged in series.
[0105] As shown in FIG. 5, the conductive loop 572C is connected to
the second connection via a bridge 573. The bridge 573 may insulate
the conductive loop 572C from the conductive loop 572B and/or the
conductive loop 572A. In some embodiments, the bridge 573 can
comprise a polymeric material, such as PET or paralyene. And in
some examples, the bridge 573 can comprise the same polymeric
material as the spacer 478 and/or the respective polymer layers of
the conductive loops 272A, 272B, and 272C, the conductive loops
372A, 372B, and 372C, and/or the conductive loops 472A, 472B, and
472C. However, in other examples, the bridge 573 can comprise a
different polymeric material than the spacer 478 and/or the
respective polymer layers. The bridge 573 may be other materials as
well, such as silicon. Moreover, in some embodiments, the bridge
573 may include an integrated circuit. And in at least one such
embodiment, the conductive loop 572A, the conductive loop 572B, and
the conductive loop 572C may cross at the bridge 573.
[0106] In the illustrated example, the plurality of conductive
loops 572 is a continuous material arranged in multiple windings,
shown as the conductive loops 572A, 572B, and 572C. However, in
other examples, a plurality of conductive loops may not be a
continuous material.
[0107] As shown in FIG. 5, the conductive loops 572A, 572B, and
572C are substantially concentric. And as shown in FIG. 5, the
conductive loops 572A, 572B, and 572C are spaced apart from each
other between the outer diameter 532 and the inner diameter 534. In
an example, the conductive loops 572A, 572B, and 572C are spaced
apart from adjacent conductive loops by a distance between 100 to
200 micrometers. Other distances are possible as well.
[0108] The conductive loops 572A, 572B, and 572C may have a width
that is the same or similar to a width of the conductive loops
272A, 272B, and 272C; the conductive loops 372A, 372B, and 372C;
and/or the conductive loops 472A, 472B, and 472C. Moreover, each of
the conductive loops in the plurality of conductive loops 572 can
comprise a respective metal layer disposed between respective
polymer layers, like the conductive loops in the plurality of
conductive loops 272 comprise a respective metal layer disposed
between respective polymer layers. In an example, the conductive
loops 572A, 572B, and 572C can be formed by a process that includes
electroplating, chemical vapor deposition, and etching, using an
inductively coupled plasma, such as oxygen plasma.
[0109] The structure 530 may be embedded in a transparent polymer,
like the structure 330 is embedded in the transparent polymer 320.
When the structure 530 is embedded in the transparent polymer, the
conductive loops 572A, 572B, and 572C may move relative to each
other. In an example, movement of the conductive loops 572A, 572B,
and 572C may be the same as movement of the conductive loops 372A,
372B, and 372C. However, in other examples, movement of the
conductive loops 572A, 572B, and 572C may be greater (or less) than
movement of the conductive loops 372A, 372B, and 372C.
[0110] For instance, when the structure 530 is embedded in the
transparent polymer and each of the conductive loops in the
plurality of conductive loops 572 comprise a respective metal layer
disposed between respective polymer layers, the metal and polymer
layers in each conductive loop in the plurality of conductive loops
572 can be spaced apart from the metal and polymer layers in each
adjacent conductive loop in the plurality of conductive loops 572.
And the transparent polymer can extend between adjacent conductive
loops in the plurality of conductive loops 572.
[0111] Moreover, the metal and polymer layers of conductive loop
572B can be spaced apart from the metal and polymer layers of
adjacent conductive loop 572A by a first distance, and the
conductive loop 572B may be spaced apart from the adjacent
conductive loop 572C by a second distance. The first and second
distances can be between 100 to 200 micrometers. Other distances
are possible as well.
[0112] The first distance could be a different value than the
second distance. For instance, the first distance can be greater
(or less) than the second distance. And the first distance and/or
the second distance could vary. As one example, the first distance
can vary based on a rotational orientation of the conductive loop
572B and/or the conductive loop 572C relative to the conductive
loop 572A. Moreover, in some embodiments, the second distance can
vary based on a rotational orientation of the conductive loop 572C
and/or the conductive loop 572A relative to the conductive loop
572B.
III. EXAMPLE METHODS
[0113] FIG. 6 is a flow chart illustrating a method, according to
an example embodiment. More specifically, the method 600 involves
forming a first polymer layer, as shown by block 602. The method
600 may then involve positioning a structure on the first polymer
layer, as shown by block 604. Further, the method 600 may then
involve conforming the structure positioned on the first polymer
layer to a curvature of the first polymer layer, as shown by block
606. The method 600 may then involve forming a second polymer layer
over the first polymer layer and the structure, as shown by block
608.
[0114] For purposes of illustration, the method 600 is described
below as being carried out by a fabrication device that utilizes
cast or compression molding. It should be understood, however, that
method 600 may be carried out by a fabrication device that utilizes
other methods for forming the polymer layers.
[0115] Moreover, for purposes of illustration, the method 600 is
described below in a scenario where a body-mountable device
comprises an eye-mountable device. It should be understood,
however, that the method 600 may involve scenarios where the
body-mountable device comprises other mountable devices that are
mounted on or in other portions of the human body. For example, the
method 600 may involve scenarios where the body-mountable device
comprises a tooth-mountable device and/or a skin-mountable device
as described herein.
[0116] A. Forming a First Polymer Layer
[0117] As mentioned above, at block 602, the fabrication device may
be used to form a first polymer layer. The fabrication device may
include molding pieces, such as molding pieces that are suitable
for cast molding. FIG. 7a illustrates a fabrication device 700 that
includes example molding pieces that may be used to form the first
polymer layer. In particular, FIG. 7a illustrates a fabrication
device 700 including a first molding piece 702 and a second molding
piece 704. The first molding piece 702 and the second molding piece
704 may define a first cavity. The second molding piece 704 may be
filled with a polymer material 706, and the polymer material 706
may be compressed into a first polymer layer 708 by the first
molding piece 702.
[0118] After the polymer material 706 is compressed into the first
polymer layer 708, the fabrication device 700 may cure the first
polymer layer 708. Curing involves the hardening of a polymer
material by cross-linking of polymer chains, and curing may be, for
example, brought about by chemical additives, ultraviolet
radiation, electron beam, and/or heat. In an example, the polymer
material 706 can be a light-curable polymer material, and the
fabrication device 700 may be configured to cure the light-curable
polymer material using light, such as ultraviolet light or visible
light.
[0119] In an example, the first polymer layer 708 may be cured to a
partially-cured state. In an example, this may involve curing the
material to a partially-cured state that is approximately 50-75% of
a fully cured state. Other partially-cured states are possible as
well. Beneficially, by partially curing the first polymer layer to
a partially-cured state, the first polymer layer 708 may have a
tackiness that facilitates adhesion thereto. With this arrangement,
the tackiness may ensure that a structure conformed to a curvature
of the first polymer layer 708 remains securely fixed in a given
location during subsequent formation steps.
[0120] The tackiness exhibited by the partially-cured first polymer
layer 708 may be different for different polymers. Accordingly, the
fabrication device 700 may be configured to cure different polymer
materials differently than other polymer materials (e.g., a first
polymer material may be cured more than a second polymer material).
Further, in addition to light curing, other methods of curing are
possible as well, such as chemical additives and/or heat. Yet still
further, in other example embodiments, the first polymer layer may
be completely cured. Alternatively, the fabrication device 700 may
bypass the curing process at this stage.
[0121] The first molding piece 702 and the second molding piece 704
may be configured to achieve a given desired thickness of the first
polymer layer 708. For instance, in an example, the first polymer
layer 708 can have a thickness of less than 150 micrometers. In an
example embodiment, the first molding piece 702 and the second
molding piece 704 can be designed so as to allow for a layer having
less than a 150 micrometer thickness between the two cavities. As
such, when the first molding piece 702 and the second molding piece
704 are pressed together during the formation of the first polymer
layer 708, the resulting polymer layer 708 will have a thickness of
less than 150 micrometers.
[0122] In an example, the thickness of the first polymer layer 708
can be selected based on a particular analyte or analytes an
eye-mountable device is configured to detect. For example, an
optimal thickness for a first analyte may be 10 micrometers, while
an optimal thickness for a second analyte may be 25 micrometers.
Other examples are possible as well.
[0123] In an example, the polymer material 706 can be any material
that can form an eye-compatible polymer layer. For example, the
polymer material 706 may be a formulation containing polymerizable
monomers, such as hydrogels, silicone hydrogels, silicone
elastomers, and rigid gas permeable materials. Further, the polymer
material 706 may form a transparent or substantially transparent
polymer layer. As such, the use of the polymer material 706 may
result in an eye-mountable device through which the wearer can see
when mounted on the wearer's eye. In an example, the polymer
material 706 can be a hydrogel material, such as silicone hydrogel.
As known in the art, hydrogel materials are commonly used in
contact-lens technology and are well-suited for eye-mountable
devices. Other materials are possible as well.
[0124] In an example, the first molding piece 702 and/or the second
molding piece 704 can be configured so as to allow sufficient pinch
off to provide for suitable edges for an eye-mountable device.
[0125] The first polymer layer 708 defines a posterior side 710 of
an eye-mountable device. That is, the first polymer layer 708
defines an outer edge of the eye-mountable device. When mounted on
an eye of a user, the posterior side 710 of the eye-mountable
device defined by the first polymer layer 708 corresponds to a side
of the device touching the eye of the user. The first molding piece
702 may be shaped so as to define a shape of the posterior side
710. For example, a curvature of the posterior side 710 may be
defined by the first molding piece 702. The second molding piece
704 may be shaped so as to define a shape of a positioning surface
711 of the first polymer layer. For example, the second molding
piece 704 may define a curvature of a positioning surface 711 of
the first polymer layer 708. In an example, a structure can be
conformed to the curvature of the positioning surface 711 of the
first polymer layer 708.
[0126] The first polymer layer 708 can further comprise an
alignment feature 712. In an example, the alignment feature 712 can
comprise an asymmetric peg. The asymmetric peg can be a variety of
shapes. For instance, the asymmetric peg can have a star-shaped or
cross-shaped cross section. Other shapes of the asymmetric peg are
possible as well.
[0127] As mentioned above, although FIG. 7a illustrates forming the
first polymer layer 708 through cast molding, other methods for
forming first polymer layer 708 are possible as well. For example,
the first polymer layer 708 may be formed via injection molding. In
injection molding, rather than polymer material being compressed
between molding pieces, molding material may be heated and injected
or otherwise forced into a molding piece or pieces. The injected
molding material may then cool and harden to the configuration of
the molding piece or pieces.
[0128] As another example, the first polymer layer 708 may be
formed via spin casting. Through spin-casting techniques, the
fabrication device may form a first polymer layer of a precise
thickness. In an example, a spin-casting mold may be spun along its
central access at a set speed, and the polymer may be introduced to
the mold as the mold is spinning in order to form a first polymer
layer. The final thickness of the first polymer layer may be
influenced by various factors, including but not limited to the
spin-casting mold, the amount of polymer introduced to the
spin-casting mold, properties of the polymer such as viscosity,
and/or the speed at which the spin-casting mold is rotated. These
factors may be varied in order to result in a first polymer layer
of a well-defined thickness.
[0129] B. Positioning a Structure on the First Polymer Layer
[0130] As mentioned above, at block 604, a structure may be
positioned on the first polymer layer. FIGS. 7b and 7c illustrate
an example in which a structure 730 is positioned on the first
polymer layer 708.
[0131] The structure 730 has an outer diameter 732 and an inner
diameter 734 and includes electronics 740, electronics 750, a
sensor 760, and an antenna 770 disposed thereon. The structure 730
may take the form of or be similar in form to the substrate 130,
the structure 230, the structure 330, the structure 430 and/or the
structure 530. In some embodiments, the structure 730 can further
include one or more spacers, such as the spacer 478.
[0132] The outer diameter 732 may take the form of or be similar in
form to the outer diameter 232, the outer diameter 332, the outer
diameter 432, and/or the outer diameter 532; the inner diameter 734
may take the form of or be similar in form to the inner diameter
234, the inner diameter 334, and or the inner diameter 434 and/or
the outer diameter 534; the electronics 740 may take the form or be
similar in form to the controller 150, the electronics 240, the
electronics 340, the electronics 440 and/or the electronics 555;
the electronics 750 may take the form of or be similar in form to
the controller 150, the electronics 250, the electronics 350, the
electronics 450, and/or the electronics 555; and the sensor 760 may
take the form of or be similar in form to the bio-analyte sensor
162, the sensor 260, the sensor 360, the sensor 460.
[0133] As noted, the structure 730 includes the antenna 770. The
antenna 770 is configured for communications and/or harvesting
energy, like the antenna 270, the antenna 370, the antenna 470, and
the antenna 570 are configured for communications and/or harvesting
energy. The antenna 770 includes a plurality of conductive loops
spaced 772 apart from each other between the outer diameter 732 and
the inner diameter 734. In the illustrated example, the plurality
of conductive loops 772 includes three conductive loops 772A, 772B,
and 772C. However, in other examples, a plurality of conductive
loops may include more than three conductive loops, such as five
conductive loops, nine conductive loops, etc.
[0134] As shown in FIG. 7b, the conductive loops 772A, 772B, and
772C are substantially concentric. And as shown in FIG. 7b, the
conductive loops 772A, 772B, and 772C are spaced apart from each
other between the outer diameter 732 and the inner diameter 734. In
an example, the conductive loops 772A, 772B, and 772C are spaced
apart from adjacent conductive loops by a distance between 100 to
200 micrometers. Other distances are possible as well. In the
illustrated example, the conductive loops 772A, 772B, and 772C are
connected in parallel. However, in other examples, conductive loops
can be connected in series, like the conductive loops 572A, 572B,
and 572C are connected in series.
[0135] In order to position the structure 730, the fabrication
device 700 may separate the first molding piece 702 from the second
molding piece 704. When the fabrication device 700 separates the
first molding piece 702 from the second molding piece 704, the
first polymer layer 708 may stick to a side of the first molding
piece 702. In an example, the first polymer layer 708 and/or the
first molding piece 702 can be surface treated, such that the first
polymer layer 708 sticks to the side of the first molding piece
702. Additionally or alternatively, the second molding piece 704
can be surface treated, such that the first polymer layer 708
sticks to the side of the first molding piece 702.
[0136] In an example, positioning the structure 730 on the first
polymer layer 708 can include aligning the structure 730 with the
alignment feature 712. In one example, the inner diameter 734 can
be asymmetric and the alignment feature 712 includes an asymmetric
peg such that the inner diameter 734 receives the alignment feature
712 in only a predetermined rotational orientation (relative
alignment between the alignment feature 712 and the inner diameter
734 in FIG. 7c is not necessarily to scale). However, other ways of
providing a predetermined rotational orientation of the structure
730 by alignment with the alignment feature 712 are also
possible.
[0137] Alternatively, the fabrication device 700 can include a
positioning apparatus (not shown), such as a robotic system,
configured to position the structure 730 on the first polymer layer
708. For instance, the positioning apparatus may (i) pick up the
structure 730 (e.g., via suction), (ii) position the structure 730
above the first polymer layer 708, and then (iii) lower the
structure 730 toward the first polymer layer 708. With this
arrangement, the positioning apparatus may position the structure
730 in a predetermined rotational orientation. When the structure
730 is positioned in a predetermined orientation, the positioning
apparatus may then release the structure 730 (e.g., by releasing
the suction). With this approach, the first polymer layer 708 might
not include the alignment feature 712.
[0138] The positioning apparatus may further include a vision
system configured to assist with positioning the structure 730 on
the first polymer layer 708. Such a vision system may facilitate
guiding the structure 730 to a precise location on the first
polymer layer 708. In an example, the vision system can be
appropriate for situations in which one or more production
specifications for an eye-mountable device, such as the
eye-mountable device 310, have requirements with very low
tolerances related to the positioning of a sensor, such as the
sensor 360, within the eye-mountable device 310.
[0139] In some situations, such as for large-scale production
purposes, it may be desirable to not only place the structure 730
in a predetermined orientation, but it may also be desirable to
repeatedly place and maintain the structure 730 at this precise
location for a plurality of eye-mountable devices. Beneficially,
fabrication of an eye-mountable device in accordance with an
example embodiment allows for such repeatable and precise
positioning.
[0140] FIG. 7c illustrates the structure 730 positioned on the
first polymer layer 708. With this arrangement, the sensor 760 may
be mounted at a particular angle along a circumference of the first
polymer layer 708. As a result, the sensor 760 may be placed at a
precise location in an XYZ plane on the first polymer layer 708. As
one example, the sensor 760 may rest at a 6 o'clock position of the
first polymer layer 708. As another example, the sensor 760 may
rest at a 12 o'clock position of the first polymer layer 708.
[0141] C. Conforming the Structure Positioned on the First Polymer
Layer to a Curvature of the First Polymer Layer
[0142] As mentioned above, at block 606, the structure positioned
on the first polymer layer may be conformed to a curvature of the
first polymer layer. FIG. 7d illustrates an example in which the
structure 730 is conformed to the curvature of the positioning
surface 711 of the first polymer layer 708.
[0143] In an example, conforming the structure 730 to the curvature
of the positioning surface 711 of the first polymer layer can
include bending the structure 730. In one example, the positioning
apparatus may bend the structure 730, such that the structure 730
conforms to the curvature of the positioning surface 711 of the
first polymer layer 708. The positioning apparatus may bend the
structure 730 by applying a force and/or a torque to one or more
portions of the structure 730. However, other ways of conforming
the structure 730 to the curvature of the positioning surface 711
are possible as well.
[0144] Moreover, in an example, during conforming the conductive
loops 772A, 772B, and 772C may move relative to each other.
Beneficially, such movement can reduce buckling of the structure
730 when it is conformed to a curvature of the first polymer layer,
such as the curvature of the positioning surface 711 of the first
polymer layer 708. An amount and/or type of movement of the
conductive loops 772A, 772B, and 772C may be based on a variety of
parameters, such as a material, a width, a thickness, and/or a
connection (e.g., parallel or series) of the conductive loops 772A,
772B, and 772C and/or a material, a thickness, and a curvature of
the first polymer layer 708. Other parameters are possible as well.
And in embodiments where the structure 730 further includes one or
more spacers, such as the spacer 478, the conductive loops 772A,
772B, and 772C may not move relative to each other based on the one
or more spacers.
[0145] During fabrication of an eye-mountable device, such as the
eye-mountable device 310, it may be desirable for the structure 730
to remain in a fixed position during fabrication of the
eye-mountable device. For instance, movement of the structure 730
during subsequent formation steps, such as formation of a second
polymer layer, may result in improper placement of the structure
730 relative to the surrounding polymer layers. As one example,
movement of the structure 730 during filling a mold piece with a
polymeric material to form the second polymer layer and/or curing
the second polymer layer can result in improper placement of the
structure 730 relative to the surrounding polymer layers.
[0146] Therefore, in an example, an adhesive is applied to the
structure 730 and/or the first polymer layer 708 before the
structure 730 is positioned on the first polymer layer 708. The
applied adhesive may facilitate adhesion of the structure 730 to
the first polymer layer 708. For instance, a small amount of
adhesive may be applied to a cured first polymer layer 708, and the
structure 730 may be conformed to a curvature of the first polymer
layer 708 and then the adhesive may be cured such that the
structure 730 adheres to the first polymer layer 708. Additionally
or alternatively, a small amount of adhesive may be applied to the
structure 730, and the structure 730 may then be conformed to a
curvature of the first polymer layer 708 (e.g., a cured first
polymer layer) and then the adhesive may be cured such that the
structure 730 adheres to the first polymer layer 708. With this
arrangement, the structure 730 may remain adhered to the first
polymer layer 708 in a secure location during subsequent formation
steps. In some embodiments, a force and/or a torque can be applied
to the structure 730 during curing of the adhesive.
[0147] As noted above, in an example, the first polymer layer 708
in a partially-cured state may have a tackiness that facilitates
adhesion thereto. With this arrangement, the structure 730 may
remain adhered to the first polymer layer 708 in a secure location
during subsequent formation steps.
[0148] D. Forming a Second Polymer Layer Over the First Polymer
Layer and the Structure
[0149] As mentioned above, at block 608, the fabrication device may
form a second polymer layer over the first polymer layer and the
structure, such that the structure is fully enclosed by the first
polymer layer and the second polymer layer. FIG. 7e illustrates the
fabrication device 700 including example molding pieces that may be
used to form the second polymer layer. In particular, FIG. 7e
illustrates a third molding piece 722. The first molding piece 702
and the third molding piece 722 may define a second cavity.
[0150] The first molding piece 702, which already holds the first
polymer layer 708 to which the structure 730 is mounted (as
illustrated in FIG. 7d), may be filled with a polymer material 724.
The polymer material 724 may be formed into a second polymer layer
726 by compression between the first molding piece 702 and the
third molding piece 722. As a result, the second polymer layer 726
may mold over the structure 730, such that the structure 730 is
fully enclosed by the first polymer layer 708 and the second
polymer layer 726. In some embodiments, the second polymer layer
can extend between adjacent conductive loops, such as the
conductive loop 772A and the conductive loop 772B and/or the
conductive loop 772B and the conductive loop 772C, in the plurality
of conductive loops 772. With this arrangement, the second polymer
layer 726 may bond to the first polymer layer 708 between the
adjacent conductive loops in the plurality of conductive loops
772.
[0151] After the second polymer layer 726 is formed, the
fabrication device 700 may cure the second polymer layer 726. In an
example, the second polymer layer 726 can be cured like the first
polymer layer 708. However, in other examples, the second polymer
layer 726 may be cured by different techniques than the first
polymer layer 708. The second polymer layer 726 can be cured by any
of the techniques mentioned herein. In an example, the fabrication
device 700 may cure the first polymer layer 708 at this stage.
[0152] After the second polymer layer 726 is cured, there may not
be a visible boundary line separating the first polymer layer 708
from the second polymer layer 726. As noted, FIG. 3a illustrates
the eye-mountable device 310. In particular, FIG. 3a illustrates
the eye-mountable device 300 includes the transparent polymer 320.
The transparent polymer 320 can be arranged like the first polymer
layer 708 and the second polymer layer 726.
[0153] Returning to FIG. 7e, the fabrication device 700 may further
comprise one or more alignment pins (not shown), such as a
plurality of dowel pins, for aligning the third molding piece 722
and the first molding piece 702. The one or more alignment pins can
assist in forming the second polymer layer 726 by aligning the
third molding piece 722 with the first molding piece 702.
[0154] The first molding piece 702 and the third molding piece 722
may be configured to achieve a given desired thickness of a layer
formed between the two pieces. As one example, the first molding
piece 702 and the third molding piece 722 may be designed so as to
define a thickness of the second polymer layer 726. As another
example, the first molding piece 702 and the third molding piece
722 may be designed so as to define a final thickness of an
eye-mountable device, such as the eye-mountable device 310. In an
example, the first molding piece 702 and the third molding piece
722 can be designed so as to allow for a layer having a given
desired thickness between the two pieces (in addition to a
thickness of the first polymer 708). As such, when the first
molding piece 702 and the third molding piece 722 are pressed
together during formation of a layer, the resulting layer will have
the given desired thickness.
[0155] In an example, the second polymer layer 726 has a thickness
of greater than 50 micrometers. However, in other examples, the
second polymer layer 726 can have a thickness between 50 and 300
micrometers, such as 130 micrometers. It should be understood that
since the second polymer layer 726 molds over the structure 730,
the second polymer layer 726 may not have a uniform thickness. For
instance, the thickness of the second polymer layer 726 above the
sensor 760 may be less than the thickness of the second polymer
layer 726 that is not touching the sensor 760.
[0156] In an example, the thickness of the second polymer layer 726
can be selected based on a particular analyte or analytes that the
eye-mountable device, such as the eye-mountable device 310, is
configured to detect. For example, an optimal thickness for a first
analyte may be 10 micrometers, while an optimal thickness for a
second analyte may be 25 micrometers. Other examples are possible
as well.
[0157] In an example, the second polymer layer 726 can be composed
of the same polymer material as the first polymer layer 708.
However, in other examples, the second polymer layer 726 can be
composed of a different polymer material than the first polymer
layer 708. The second polymer layer 726 can be any one of the
polymer materials mentioned herein. In an example, the structure
730 can be more rigid than the second polymer layer 726.
[0158] The second polymer layer 726 defines an anterior side 728 of
an eye-mountable device. That is, the second polymer layer 726
defines an outer edge of the eye-mountable device. When mounted on
an eye of a user, the anterior side 728 of the eye-mountable device
defined by the second polymer layer 726 corresponds to the side of
the device that is not touching the eye of the user. The third
molding piece 722 may be shaped so as to define a shape of the
anterior side 728. For example, a curvature of the anterior side
728 may be defined by the third molding piece 722.
[0159] E. Forming the First Polymer Layer and the Second Polymer
Layer at the Same Time
[0160] The example methods described above involve a method of
fabricating an eye-mountable device that involves first forming a
first polymer layer and subsequently forming a second polymer
layer. In another example, the first polymer layer defining a
posterior side of the eye-mountable device and the second polymer
layer defining an anterior side of the eye-mountable device may be
substantially formed around a structure, such as the structure 730,
at the same time. The term "substantially formed," as used in this
disclosure, refers to exactly formed and/or one or more deviations
from exactly formed that do not significantly impact embedding a
structure in a body-mountable device as described herein. Further,
in such an example, positioning the structure on the first layer
and conforming the structure positioned on the first layer to a
curvature of the first layer would take place at the same time as
the formation of the first polymer layer and the second polymer
layer.
[0161] For instance, in accordance with an example embodiment, the
fabrication device may be configured to position a structure within
a molding cavity or cavities, and the fabrication device may then
form the first polymer layer and the second polymer layer around
the structure. In such an example, the fabrication device may be
configured to inject mold into the molding cavity, and the injected
mold may encapsulate the structure. In this example, the
fabrication device may include a molding cavity or cavities that
have at least one opening configured to allow the fabrication
device to hold the structure in place as the first and second
polymer layers are formed around the structure. The molding cavity
or cavities may be filled with the polymer material, and this
introduction of the polymer material may form the polymer layers
around the structure.
[0162] F. Forming a Channel Through the Second Polymer Layer
[0163] In some embodiments, the example methods described above may
further include forming a channel through a second polymer layer,
such that a sensor (e.g., sensor 760), is configured to receive one
or more analytes via the channel. In such an example, the channel
may be formed by removing material from the second polymer layer.
The material from the second polymer layer can be removed to form
the channel in a variety of ways. For instance, the material from
the second polymer layer can be removed to form the channel via a
process that includes drilling, ablation, etching, etc.
[0164] In another example, a mask layer may be formed before
forming the second polymer layer. Further, in such an example,
after the second polymer layer is formed, the mask layer may be
removed to form a channel. The mask layer can be removed to form
the channel in a variety of ways. For instance, the mask layer can
be removed to form the channel via a process that includes etching
the mask layer and/or dissolving the mask layer in a fluid.
IV. CONCLUSION
[0165] It should be understood that arrangements described herein
are for purposes of example only. As such, those skilled in the art
will appreciate that other arrangements and other elements (e.g.,
machines, interfaces, functions, orders, and groupings of
functions, etc.) can be used instead, and some elements may be
omitted altogether according to the desired results. Further, many
of the elements that are described are functional entities that may
be implemented as discrete or distributed components or in
conjunction with other components, in any suitable combination and
location.
[0166] While various aspects and embodiments have been disclosed
herein, other aspects and embodiments will be apparent to those
skilled in the art. The various aspects and embodiments disclosed
herein are for purposes of illustration and are not intended to be
limiting, with the true scope and spirit being indicated by the
following claims, along with the full scope of equivalents to which
such claims are entitled. It is also to be understood that the
terminology used herein is for the purpose of describing particular
embodiments only, and is not intended to be limiting.
[0167] Where example embodiments involve information related to a
person or a device of a person, some embodiments may include
privacy controls. Such privacy controls may include, at least,
anonymization of device identifiers, transparency and user
controls, including functionality that would enable users to modify
or delete information relating to the user's use of a product.
[0168] Further, in situations in where embodiments discussed herein
collect personal information about users, or may make use of
personal information, the users may be provided with an opportunity
to control whether programs or features collect user information
(e.g., information about a user's medical history, social network,
social actions or activities, profession, a user's preferences, or
a user's current location), or to control whether and/or how to
receive content from the content server that may be more relevant
to the user. In addition, certain data may be treated in one or
more ways before it is stored or used, so that personally
identifiable information is removed. For example, a user's identity
may be treated so that no personally identifiable information can
be determined for the user, or a user's geographic location may be
generalized where location information is obtained (such as to a
city, ZIP code, or state level), so that a particular location of a
user cannot be determined. Thus, the user may have control over how
information is collected about the user and used by a content
server.
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