U.S. patent application number 14/297958 was filed with the patent office on 2014-09-25 for three-dimensional adhesive device having a microelectronic system embedded therein.
This patent application is currently assigned to CUTISENSE A/S. The applicant listed for this patent is CUTISENSE A/S. Invention is credited to Jens Branebjerg, Susanne Holm FAARBAEK, Karsten Hoppe, Peter Boman Samuelsen.
Application Number | 20140288381 14/297958 |
Document ID | / |
Family ID | 36953725 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140288381 |
Kind Code |
A1 |
FAARBAEK; Susanne Holm ; et
al. |
September 25, 2014 |
THREE-DIMENSIONAL ADHESIVE DEVICE HAVING A MICROELECTRONIC SYSTEM
EMBEDDED THEREIN
Abstract
A three-dimensional adhesive device to be attached to the body
surface of a mammal including a microelectronic sensing system. The
system includes (a) a three-dimensional adhesive body made of a
pressure sensitive adhesive having an upper surface and a bottom
surface; (b) a microelectronic system embedded in the body of the
pressure sensitive adhesive; (c) one or more cover layer(s)
attached to the upper surface; and (d) optionally a release liner
releasably attached to the bottom surface. Suitably the
microelectronic system is capable of sensing physical input such as
pressure, vibration, sound, electrical activity (e.g. from muscle
activity), tension, blood-flow, moisture, temperature, enzyme
activity, bacteria, pH, blood sugar, conductivity, resistance,
capacitance, inductance or other chemical, biochemical, biological,
mechanical or electrical purposes.
Inventors: |
FAARBAEK; Susanne Holm;
(Vaerloese, DK) ; Hoppe; Karsten; (Copenhagen,
DK) ; Samuelsen; Peter Boman; (Rungsted Kyst, DK)
; Branebjerg; Jens; (Hoersholm, DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CUTISENSE A/S |
HORSHOLM |
|
DK |
|
|
Assignee: |
CUTISENSE A/S
HORSHOLM
DK
|
Family ID: |
36953725 |
Appl. No.: |
14/297958 |
Filed: |
June 6, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11886032 |
Apr 3, 2008 |
|
|
|
PCT/DK2006/050006 |
Mar 9, 2006 |
|
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14297958 |
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Current U.S.
Class: |
600/300 |
Current CPC
Class: |
A61B 5/024 20130101;
A61B 5/14542 20130101; A61B 5/0478 20130101; A61B 5/14546 20130101;
A61B 5/68335 20170801; A61B 5/14532 20130101; A61B 2562/08
20130101; A61B 5/6833 20130101; A61B 5/0492 20130101; A61B 5/14539
20130101; A61B 2560/0412 20130101; Y10T 29/49002 20150115; A61B
5/02 20130101; Y10T 428/14 20150115; A61B 5/0002 20130101; A61B
5/411 20130101; A61B 5/04087 20130101 |
Class at
Publication: |
600/300 |
International
Class: |
A61B 5/00 20060101
A61B005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2005 |
DK |
PA 2005 00354 |
Dec 9, 2005 |
DK |
PA 2005 01748 |
Claims
1. A sensor assembly adapted to be attached to the body surface of
a mammal, comprising: a sensor circuit including a plurality of
electrical components; an adhesive device including at least one
power source for powering at least one of said plurality of
electrical components and at least one adhesive for attaching the
sensor assembly to the body surface of a mammal; and said adhesive
device being adapted to be releasably connected to the sensor
circuit.
2. The sensor assembly according to claim 1, wherein the sensor
circuit is at least partially contained in a housing, said housing
being formed of a proximal housing part and a distal housing
part.
3. The sensor assembly according to claim 2, wherein a recess is
formed in the distal housing part, the recess being adapted to
receive the at least one power source, the adhesive is applied to
the distal side of the housing and the distal side of the at least
one power source, and a first peel force between the adhesive and
the housing is smaller than a second peel force between the
adhesive and the at least one power source.
4. The sensor assembly according to claim 3, wherein at least one
transducer is attached to a proximal surface of the proximal
part.
5. The sensor assembly according to claim 2, wherein at least one
transducer is attached to a proximal surface of the proximal
part.
6. The sensor assembly according to claim 3, wherein at least one
electrical contact is provided in the distal housing part providing
electrical connection between the at least one power source and the
electrical components.
7. The sensor assembly according to claim 2, wherein at least one
electrical contact is provided in the distal housing part providing
electrical connection between the at least one power source and the
electrical components.
Description
[0001] This application is a divisional application of co-pending
application Ser. No. 11/886,032, filed Apr. 3, 2008, which was a
national stage of PCT/DK06/050006 filed Mar. 9, 2006 and published
in English, the priority of which is hereby claimed.
FIELD OF INVENTION
[0002] The invention relates to micro electronic systems
predominantly for monitoring physiological or neurological
conditions. More particular the invention relates to invasive and
non-invasive microelectronic systems embedded in a
three-dimensional adhesive device, which may be attached to the
surface, suitably the skin, of a mammal. The microelectronic
systems suitably utilises wireless communication and are useful for
measuring ECG (Electro CardioGraphy), EMG (Electro MyoGraphy), EEG
(Electro EncephaloGraphy), blood glucose, pulse, blood pressure,
pH, and oxygen.
BACKGROUND
[0003] The attachment of sensing systems to the skin by means of
pressure sensitive adhesives is well established. Thus, AMBU A/S,
DK has a number of products for measuring ECG, which is attached to
the skin by foam adhesives, micro-porous adhesives or hydrogel
adhesives. These sensors are in general connected with wires to a
monitoring device.
[0004] In WO 03/065926 A2 Ozgus et al disclose a wearable
biomonitor with a flexible and thin integrated circuit. The patent
application addresses a way to achieve high comfort of wear by
using a thin layer adhesive or pads of adhesive for fixation to the
skin. However, the adhesives used are occluding. The application
further describes a sensor module for wireless data collection
having a thin sheet of silicon comprising the circuit and a
flexible power source being build into the sensor module as
layers.
[0005] In U.S. Pat. No. 5,054,488 Mus et al disclose an
opto-electronic sensor for producing electrical signals
representative of a physiological condition. The sensors may be
attached to the body by a double-sided pressure sensitive adhesive
on a polyester lining.
[0006] In U.S. Pat. No. 5,458,124 Stanko et al disclose
electro-cardiographic-electrodes being attached to the body by
double-sided pressure sensitive adhesive.
[0007] In U.S. Pat. No. 6,372,951 Ter-Ovanesyan et al disclose a
sensor operatively connected to a disposable article, fitted to the
wearer by an adhesive patch. A wide variety of body adhering
compositions may be used.
[0008] In U.S. Pat. No. 6,385,473 Haines et al disclose a laminated
sensor device attached to mammalian subject with two strips of
hydrocolloid adhesive. The laminated structure consists also of
hydrogel in contact with hydrocolloid adhesive. The lifetime of the
device is specified to 24 hrs.
[0009] In WO 99/59465 Feierbach et al disclose an apparatus for
monitoring the physiological condition of a patient. The apparatus
includes a patch having a distal side for being fixed to the
patient. Also the apparatus may include an electronics housing that
may be coupled with said patch. In one embodiment the surface of
the apparatus may be pre-formed to the contours of a body part. The
patch carrying the electronic housing may be soft and provide a
natural feel and may be produced from latex, silicon or another
rubberised fabric. The upper surface of the patch with the
electronic housing may have a smooth convex shape as illustrated in
FIG. 2B and FIG. 8 of the patent. The patch is coupled to the skin
of the patient by an adhesive. Such adhesive may be a hydrocolloid
skin protective adhesive manufactured by 3M. Hence the patent
application teaches the use of a hydrocolloid adhesive liner for
fixation of a sensor having a smooth and soft backing optionally in
a pre-formed shape to fit a contour of the body.
[0010] In US application 2003/0009097 A1 Sheraton et al disclose a
sensor having a hydrogel electric conducting central skin
contacting part and a hydrocolloid adhesive part surrounding this
central part for adhesion of the sensor and on said combined disc a
conductive terminal connected to a wire. This construct is further
protected by laminate film layers adhered to the terminal and the
outer rim of adhesive. The patent application teaches the use of
hydrocolloid adhesives for fixation of sensors to the skin and
emphasizes the aspect of making very thin and flexible electrodes.
The patent application is peculiar in the sense that it combines
the use of hydrocolloid adhesives and hydrogels. For any practical
purpose the disclosed constructs will be useless as the moisture
from the hydrogel will migrate into the hydrocolloid adhesive and
disrupt this over time.
[0011] Recent developments in devices for monitoring physiological
conditions are wire-less types. Apart from being able to monitor a
physiological condition invasively or non-invasively and
potentially compare to a reference, they are be able to process
data and transmit them to a portable device. In fact the attachable
device may also function as an alarm itself, e.g. by use of e.g.
light emission, audio alarm or another warning signal.
[0012] When monitoring physiological or neurological conditions of
the human body it is important that the attached microelectronic
system is as comfortable to wear as possible, especially when the
person carrying the device is not bedridden and shows normal
physical activity or even excess physical activity like in sport or
in sports medicine. The user should preferably not feel the
attached microelectronic system and the monitoring should
preferably be kept in private. However, in this respect the known
microelectronic systems suffer from several major drawbacks as
described below.
[0013] Attachment to the skin by means of occlusive pressure
sensitive adhesives often leads to skin irritation due to the
occlusion of moisture and due to irritants, such as monomers from
the pressure sensitive adhesive polymer system, e.g. from for
instance acrylic adhesives. Irritation may be the in form of
itching and erythema and may especially develop when the adhesive
device is attached for a prolonged period of time. Occlusion may
also increase the risk of creating allergy to the adhesive
composition. One often used way to solve the negative effects of
occlusion is to use micro porous tapes, but such tapes are
essentially two-dimensional and thin and does not protect the
microelectronic system from shear forces due to friction against
clothes and the like.
[0014] In the above references, the devices are attached to the
skin by thin planar adhesive layers carrying the microelectronic
system as a bulky part leading to discomfort of the patient or
person carrying the device due to stiffness or friction against
clothing and increasing the risk of involuntarily detachment from
the skin. When such a device is to be used for a prolonged period
of time, it is important to reduce any type of discomfort due to
skin irritation or inconvenience of carrying a bulky device.
Furthermore it is crucial for the signal detection that the
adhesive device is kept fixed to the skin until it is deliberately
removed.
[0015] Proper adhesion of the device requires a fairly thick layer
of the planar adhesive. However, a fairly thick layer may show a
tendency of adhering at the edge to clothing or linen and by doing
so a tendency to roll and detach is created.
[0016] Many sensors are connected to the monitoring systems with
wires. The disadvantage of such a system is that the patient does
not have freedom to move since the wires are attached to the
sensors on the body and connected to a monitoring system. Whenever
the patient wants to move he must be careful not to dislodge any of
the wires attached to the sensors, and he must further pick up the
monitoring system and carry it along.
[0017] None of the above mentioned references describes a body
sensor device consisting of an optionally hydrocolloid containing
thermoplastic pressure sensitive adhesive and/or chemically curing
pressure sensitive adhesive, moulded or cast into a
three-dimensional adhesive body having a micro electronic system
embedded therein as according to the present invention.
[0018] The known sensors overcoming some of the above-mentioned
disadvantages are not as simple and inexpensive to manufacture with
respect to the adhesive part of the device as the adhesive devices
of the invention.
[0019] The adhesive devices of the invention having a
microelectronic system embedded therein may be produced relatively
easily and besides a cover layer and optionally a release layer,
without the need of any other layers in the device and is therefore
commercially attractive.
[0020] With an embedment of the micro electronic components an
improved protection against mechanical damage and penetration of
moisture from the surrounding environment is also achieved.
[0021] Furthermore, today many types of electronics are temporarily
attached to different surfaces. Especially within medical care
different types of medical devices such as probes and sensors are
attached to different areas of the skin in order to, for example,
detect different biomedical signals or retrieve samples from a
patient. Often these medical devices are only attached for a
limited period of time until a disease is diagnosed or a patient's
health has improved. However, some chronic diseases may require
periodical monitoring, for example while the patient is sleeping,
or in some cases constant monitoring is desired day and night. The
medical device, which is attached to the skin of the patient, may
be adapted to detect many types of signals, it could for example be
a sensor for detecting one or more signals such as
electromyographic (EMG) signals, electrocardiographic (ECG) signals
and electroencephalography (EEG) signals.
[0022] Such medical devices may be broken up into at least three
general elements, a microelectronic element for measuring a desired
value, such as for example a biosignal; an adhesive for attaching
the microelectronic element to a surface; and a power source for
powering at least a part of the microelectronic circuit.
[0023] The different elements have different lifespan, however,
since the elements are typically assembled in one inseparable unit
they are all disposed after use. When looking at the elements
individually it may however be understood that they have different
lifespan. Thus, the adhesive element typically has a one-time use
only. The power source may in some cases be reused a few times
depending on the application and the size of the battery. However,
the microelectronic element may be reused a large number of times
thereby making it an expensive element to dispose after one use
only.
[0024] Thus in order to improve the cost effectiveness of the
medical device there exists a need to be able to reuse the
element(s), which are still operable after use.
[0025] US 2002/0180605 discloses a method of monitoring a
physiological characteristic. The method disclosed can include
subsequent steps of removing adhesive pads from a sensor module and
heating the sensor module in an autoclave for sterilization after
data has been transferred from the sensor module to the receiver
module.
SUMMARY OF THE INVENTION
[0026] Accordingly, the present invention relates to a
three-dimensional adhesive device comprising an microelectronic
sensing system characterized by
[0027] (a) a three-dimensional adhesive body made of a pressure
sensitive adhesive having an upper surface and a bottom
surface;
[0028] (b) a microelectronic system embedded in the body of the
pressure sensitive adhesive;
[0029] (c) one or more cover layer(s) attached to the upper
surface; and
[0030] (d) optionally a release liner releasable attached to the
bottom surface of the adhesive device.
[0031] Suitably, the microelectronic system is a microelectronic
sensing system. The microelectronic sensing system is suitably
capable of sensing physical input such as pressure, vibration,
sound, electrical activity (e.g. from muscle activity), tension,
blood-flow, moisture, temperature, enzyme activity, bacteria, pH,
blood sugar, conductivity, resistance, capacitance, inductance or
other chemical, biochemical, biological, mechanical or electrical
input.
[0032] These and other objects of the invention, as well as many of
the intended advantages thereof, will become more readily apparent
when reference is made to the following description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 shows a die section of the shape of a typical
representative of the adhesive device according to the invention.
CT is the maximal thickness of the device and PT is the thickness
in the periphery of the device.
[0034] FIG. 2 illustrates a microelectronic system
embedded/integrated in a three-dimensional (3D) adhesive. The
zoom-box indicates the part of the adhesive device illustrated in
FIGS. 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12.
[0035] FIG. 3 illustrates a microelectronic system (hatched box)
that is completely integrated within the adhesive body.
[0036] FIG. 4 illustrates that parts of the microelectronic system
may be positioned in different locations integrated within the
adhesive device with proper mechanical or electrical
interconnection between the parts.
[0037] FIG. 5 illustrates a microelectronic system, which is
applied into a recess in the adhesive body. The recess is distal to
skin fixation area. The microelectronic system may optionally be
exchangeable, or reusable.
[0038] FIG. 6 illustrates the microelectronic system in which the
upper part may be exchangeable or reusable and the lower part be
permanently integrated in the adhesive body.
[0039] FIG. 7 illustrates that parts of the microelectronic system
may be situated in different locations within the adhesive device
with proper mechanical or electrical interconnection between the
parts.
[0040] FIG. 8 illustrates a microelectronic system, which is
embedded/applied into a recess on the adhesive side of the adhesive
body.
[0041] FIG. 9 illustrates a device with a microelectronic system in
which the lower part may be exchangeable or reusable and the upper
part be permanently integrated in the adhesive body.
[0042] FIG. 10 illustrates a system with some microelectronic
components integrated within the adhesive body during production
(small hatched box) and some microelectronic components applied
later thereby establishing the necessary mechanical/electrical
connections.
[0043] FIG. 11 illustrates a microelectronic system embedded in the
adhesive which system is applicable and accessible both from the
distal side and the skin fixation side of the adhesive body.
[0044] FIG. 12 illustrates a system where the microelectronic
system is assembled from two parts one of which, or each of which
may be exchangeable or reusable.
[0045] In all the above constructs of the invention the upper
surface remains smooth irrespective the presence of components of
the microelectronic system at the upper surface. This may be
achieved by proper construction of the microelectronic components,
encapsulation etc.
[0046] The constructions shown in FIGS. 8, 9, 10, 11 and 12 are
particularly suitable for microelectronic systems including an
element, e.g. an electrode which should have skin contact.
[0047] FIGS. 13-18 illustrates an embodiment of the invention where
an antenna, a Central Processing Unit, a battery and electrodes are
embedded in an adhesive device. FIG. 13 illustrates the
two-dimensional shape of the device indicating a cross-section by
A-A. In FIG. 15 the third dimension is shown as the cross-section
A-A. The circle B from the rim of the device is further magnified
in FIG. 16 and the circle C of the centre is like wise magnified in
FIG. 17. FIG. 14 illustrates the position of the antenna placed in
the outer part of the adhesive device and being connected to the
central part of the microelectronic system. FIG. 16 shows more in
detail the building of the antenna lying embedded in the adhesive.
FIG. 17 shows the position of the central part of the
microelectronic system with a battery, a CPU and an electrode
protruding the adhesive. The battery and the CPU are enveloped in a
transparent silicone rubber. Finally FIG. 18 illustrates the
adhesive device in a three-dimensional mode.
[0048] FIG. 19 shows one embodiment of a sensor assembly according
to the invention seen in a exploded perspective view.
[0049] FIG. 20 shows the embodiment of a sensor assembly in a
sectional view along line XX-XX in FIG. 19.
[0050] FIG. 21 shows the embodiment of a sensor assembly seen from
the bottom.
[0051] FIGS. 22a and 22b shows another embodiment of a device
according to the invention wherein FIG. 22b shows a portion of FIG.
22a in an enlarged view.
[0052] FIG. 23 shows yet another embodiment of a device according
to the invention seen in a perspective view.
[0053] FIG. 24 shows the embodiment of a device according to the
invention in a sectional view along line XXIV-XXIV in FIG. 23.
DETAILED DESCRIPTION OF THE INVENTION
[0054] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
[0055] The present invention relates to adhesive devices having a
microelectronic system embedded in an adhesive body made from a
pressure sensitive adhesive.
[0056] In the following the term "three-dimensional" used when
defining an element e.g. an adhesive body or device, refers to an
element having a considerable varying contour when seen in cross
section. Thus, for example a three-dimensional adhesive body will
have a maximum thickness and a minimal thickness. According to the
invention the maximum thickness will be at least twice the
thickness of the minimal thickness. In a preferred embodiment the
outer rim or the peripheral edge of the adhesive device has a
thickness which is less than half of the thickest part of the
sensor, normally the central part.
[0057] In contrast to the term "three-dimensional" the term
"two-dimensional" used when defining an element refers to an
element, which has a generally planar surface. Thus, the maximum
thickness of a two-dimensional adhesive body is below two times the
minimal thickness of the adhesive body.
[0058] As used herein in relation to the micro electronic system or
components thereof, the term "embedded", means that the pressure
sensitive adhesive of the adhesive body is surrounding all or some
of components of the micro electronic system, either partly or
fully. Thus, the term embedded covers the situation where all sides
of the system or component(s) is covered by the adhesive of the
adhesive body and also the cases where not all sides of the
embedded item is covered with the adhesive of the adhesive body,
e.g. when the item is placed in a recess or cavity in the adhesive
body and is accessible from the outside.
[0059] As "embedded" is the general term used for the description
of the way the micro electronic system is positioned in the
adhesive body the term "integrated" means that the micro electronic
system or specific components thereof are covered by adhesive on
all sides and the term "applied" is used when the micro electronic
system only is partly covered.
[0060] Integrated and covered on all sides also covers the
situation where the integrated component is connected, e.g.
electrically or otherwise to another component embedded in the
adhesive body.
[0061] As used herein, a microelectronic "sensing" system means a
microelectronic system comprising a transducer having an element
capable of detecting a physiological or neurological condition.
[0062] As used herein through hole means a hole through the
adhesive body having opening(s) at the upper surface of the
adhesive body and opening(s) at the bottom surface of the adhesive
body. Preferably the through hole has one opening at the upper
surface and one at the bottom surface of the adhesive body. The
through hole may have any suitable shape.
[0063] By the "thickness" of the adhesive device is meant the
length of the shortest line which may be drawn between a specific
point on the upper surface to a point on the bottom surface, or the
shortest line which may be drawn between a specific point on the
bottom surface to a point on the upper surface.
[0064] For the purpose of the present invention the expression
"skin" is used to designate the outer surface of mammals.
[0065] As mentioned above, it has surprisingly been found that a
wire-less microelectronic systems in which the micro electronic
parts are embedded in a three-dimensionally shaped pressure
sensitive adhesive body solve the problems of the known sensor
devices.
[0066] Due to the properties of the three-dimensional pressure
sensitive adhesives, an optimal protection of the micro electronic
system is created. The adhesive provide sealing towards the skin
surface and the adhesive device is protected from exterior liquids
due to the polymeric cover layer(s) on top of the adhesive device.
Furthermore the adhesive protects the embedded micro electronic
parts from mechanical damage.
[0067] The adhesive bodies according to the invention are made from
pressure sensitive adhesives that are shaped three-dimensionally,
having a varying thickness from the centre to the peripheral edge
of the adhesive body and having the micro electronic sensing system
embedded within the adhesive body, suitably where the adhesive body
is thickest.
[0068] A device with such a shape and suitably with bevelled edges
provides a smooth interface with the skin. The adhesive device will
give a gentle feel and will not tend to give friction to clothes
and linen. A special advantage will be that the adhesive device
will less easily involuntarily fall off due to bulkiness and
adhesiveness at the edge. This is very important to the very
function of the device.
[0069] Moreover, the construction of the adhesive device is simple
and convenient as the adhesive body have a triple function as the
means for fixation of the device to the skin, the means for
protection of the microelectronic system and the means for shaping
the device into a convenient shape. The construction require less
components and process steps in the assembly of the
three-dimensional device and is therefore less expensive and easier
to manufacture.
[0070] According to one embodiment of the invention, the
three-dimensional adhesive body has an essentially planar bottom
surface adapted to adhere to the body surface of a mammal and an
smooth upper surface. The adhesive device is suitably thickest at
the central part of the body and thinnest at the periphery of the
body. Preferably, the upper surface has a smooth convex surface,
but it may in principle take any form.
[0071] The outer rim or the peripheral edge of the adhesive device
must be shaped to a thickness less than half of the thickest part
of the sensor, normally the central part.
[0072] Thus, in a further embodiment of the invention, the
thickness of the adhesive device at the periphery is less than 50%
of the thickness of the adhesive device where it is thickest,
suitably the thickness at the periphery is less than 25% of the
thickness of the adhesive device where it is thickest, preferred
the thickness at the periphery is less than 10% of the thickness of
the adhesive device where it is thickest, and most preferred the
thickness at the periphery is less than 5% of the thickness of the
adhesive device where it is thickest.
[0073] The thickness at the periphery of the adhesive device is
typically under 0.4 mm. In one embodiment the thickness may be
between 0.01 and 0.4 mm. Suitably, the thickness at the periphery
of the adhesive device is above 0.05 mm, preferably between
0.05-0.4 mm.
[0074] Typically the adhesive device is between 0.5 and 15 mm, more
suitably between 1-5 mm where it is thickest, typically but not
necessarily, at the centre of the adhesive body.
[0075] Suitably, the angle between the bottom surface of the
adhesive device and a line drawn from any point of the
circumference of the bottom surface and the point at the upper
surface where the adhesive body is thickest is below 60 degrees,
preferably below 45 degrees and most preferably below 30
degrees.
[0076] The outer rim of the adhesive body may suitably be shaped
circular or oval, with or without flaps and lobes, or it may be
shaped rectangular or triangular to obtain as convenient and safe a
device as possible.
[0077] Normally the outer rim of the adhesive body will consist of
the adhesive of the adhesive body. However, there may be
embodiments where the microelectronic system or component(s)
thereof, is placed in/or at the outer rim, whereby the outer rim
does not solely consists of the adhesive of the adhesive body.
[0078] The pressure sensitive adhesive making up the
three-dimensional adhesive body is suitably a mouldable
thermoplastic or chemically curing pressure sensitive adhesive
having a flexibility enabling the adhesive device to conform to the
curvature of body parts while retaining its adhesive properties
even under movements.
[0079] Suitable, pressure sensitive adhesives making up the
adhesive body is an adhesive based on polymers selected from
block-copolymers such as styrene-block-copolymers, and hydrogenated
styrene-block-copolymers, amorphous poly-alpha-olefins (APAO),
polyacrylics, polyvinylethers, polyurethanes,
polyelhylenevinylacetate, silicone or from the group of hydrogel
pressure sensitive adhesives.
[0080] Pressure sensitive adhesives based on these polymers are
known and the skilled person knows how to prepare adhesives based
on these polymers.
[0081] The block-copolymers, such as styrene-block-copolymers, and
hydrogenated styrene-block-copolymers, may suitable be selected
from Styrene/ethylene-Butylene/Styrene (SEBS),
Styrene/Isoprene/Styrene (SIS), and
Styrene/Ethylene-Propylene/Styrene (SEPS).
[0082] The adhesive may also be based on PDMS
(polydimethylsiloxane), and may suitably be a PDMS gel.
[0083] Hydrogel adhesives may also be based on or comprise
amfifilic polymers, polyvinylpyrrolidone, polyvinyl alcohol,
polyethyleneoxide, gelatins, natural gums and cellulose derivatives
or any combinations thereof.
[0084] The pressure sensitive adhesive may be formulated according
to the principles and based on the polymers listed and disclosed in
the handbook of Donatas Satas: Handbook of pressure sensitive
adhesive technology, Third edition.
[0085] In one particular embodiment of the invention, the pressure
sensitive adhesive making up the adhesive body comprises
hydrocolloids. The pressure sensitive adhesive comprising the
hydrocolloids may be any of the above-mentioned types of pressure
sensitive adhesive or any other pressure sensitive adhesive known
in the art.
[0086] Thus, U.S. Pat. No. 3,339,549 discloses a blend of a rubbery
elastomer such as polyisobutylene and one or more water-soluble or
water swellable hydrocolloids such as a powdery mixture of pectin,
gelatine and carboxymethylcellulose. The adhesive mass has a
water-insoluble film applied to one surface. A composition of this
type is available commercially from E.R. Squibb & Sons Inc.
under the trademark "Stomahesive" and is used as a skin barrier
around stomas to prevent skin breakdown by the corrosive fluids
discharged by the stoma.
[0087] In adhesive compositions of this type, the polyisobutylene
is responsible for provision of the adhesive properties and the
dispersed hydrocolloid powders absorb fluid and render the adhesive
agent capable of also adhering to moist skin (wet tack). These
compositions are also gaining increasing acceptance as wound
dressings for dermal ulcers, burns and other exuding wounds.
[0088] In a number of embodiments, styrene copolymers have been
incorporated which are disclosed in a number of patent references.
Thus, U.S. Pat. No. 4,231,369 Sorensen et al. disclose an ostomy
skin barrier consisting of a styrene copolymer having dispersed
therein a water-soluble hydrocolloid gum and a tackifier.
[0089] In U.S. Pat. No. 4,367,732 Poulsen et al. disclose an ostomy
skin barrier consisting of a water soluble hydrocolloid dispersed
in a continuous phase consisting of a styrene copolymer, a
hydrocarbon tackifier, and a plasticizer, an antioxidant, and an
oily extender.
[0090] U.S. Pat. No. 4,551,490 (Doyle et al.) discloses medical
grade pressure sensitive adhesive compositions comprising a
homogeneous mixture of 5-30% of one or more polyisobutylenes, 3-20%
of one or more styrene radial or block type copolymers having a
content of diblock copolymer below 20%, mineral oil, one or more
water soluble hydrocolloid gums, and a tackifier. One or more water
swellable cohesive strengthening agents, an antioxidant, and
various other optional ingredients also may be included within the
adhesive composition.
[0091] U.S. Pat. No. 5,492,943 discloses a pressure sensitive
adhesive composition including a blend of two viscoelastic adhesive
elastomers, specifically, high molecular weight polyisobutylene and
a styrene block copolymer, which along with a plasticizer
(preferably petrolatum) and a suitable tackifier and antioxidant,
form a continuous phase in which hydrocolloids such as sodium
carboxymethylcellulose and pectin are dispersed.
[0092] In U.S. Pat. No. 4,867,748 Samuelsen disclose geometries of
sealing pads from hydrocolloid adhesives combined with backing
films and the processing of such.
[0093] The adhesive compositions disclosed in U.S. Pat. No.
5,492,943 are stated to be used for wafers for adhering ostomy
appliances to the skin and differ from known compositions by
comprising styrene block-copolymers having a higher content of
diblock copolymer, completely avoiding the use of low molecular
weight polyisobutylene and furthermore by preferably not including
gelatine.
[0094] Pressure sensitive adhesives containing hydrocolloids is a
particularly suitable group of adhesives being characterized by
having a particulate phase of hydrocolloids dispersed in the
adhesive phase. An adhesive containing hydrocolloids may absorb
moisture from the skin avoid occlusion of the skin, while
maintaining its adhesive properties to skin. Moreover, and adhesive
body containing hydrocolloids may have any thickness and still
having the non-occlusive properties. A hydrocolloid adhesive may be
processed as a hot melt and is easily moulded into specific
shapes.
[0095] This means that the hot melt property combined with the easy
moulding enables graduation of the thickness of the adhesive body
from the edge of the adhesive device comprising the microelectronic
system to the central parts giving a smooth non-abrupt projecting
profile. Recipes for making pressure sensitive adhesives useful for
an adhesive body according to the invention are described in more
detail below.
[0096] Thus, a typical pressure sensitive adhesive composition
comprises a substantially homogeneous mixture of 10-60 weight
percent of one or more rubbery elastomeric components, 5-60% of one
or more absorbent particles, 0-50% tackifier resin, 0-10% of a
plasticiser and 0-60% of a non-polar oily extender, based on the
total weight of the composition.
[0097] The rubbery elastomeric base could be selected from the
group consisting of physically cross-linked elastomers (suitably
block copolymers containing polystyrene blocks), a chemically
cross-linked natural or synthetic rubbery elastomer, or a rubbery
homopolymer.
[0098] A physically cross-linked elastomer selected from
block-copolymers of styrene, and one or more butadienes may be a
styrene-butadiene-styrene block copolymer, a styrene-isoprene
copolymer and is preferably a mixture of styrene-isoprene-styrene
and styrene-isoprene block copolymers.
[0099] A chemically cross-linked rubbery elastomer may be e.g.
butyl rubber or natural rubber.
[0100] A rubbery homopolymer may be a polymer of a lower alkene
such as low density polyethylene or propylene, preferably atactic
polypropylene (APP) or polyisobutylene.
[0101] A tackifying resin optionally used in accordance with the
invention is preferably a hydrogenated tackifier resin and is more
preferred selected from a group comprising polymers and copolymers
of cyclopentadiene, dicyclopentadiene, alpha-pinene or
beta-pinene.
[0102] When the physically cross-linked elastomer is a
styrene-butadiene-styrene block copolymer or a
styrene-isoprene-styrene block copolymer, the adhesive suitably
comprise 0-10% of a plasticiser e.g. (citrofol BII, DOA).
[0103] The swelling hydrocolloid particles preferably consist of
one or more water-soluble or water swelling hydrocolloid polymers
or gums.
[0104] Suitable hydrocolloids include synthetic polymers that may
be either linear or cross-linked, such as hydrocolloids prepared
from lactams or polyvinyl pyrrolidone. Other monomers useful to
prepare a synthetic hydrocolloid include acrylates, methacrylates
and watersoluble amides.
[0105] Other hydrocolloidal polymers, either naturally occurring or
synthetically prepared, are useful according to the present
invention. These materials include polyvinyl alcohol,
polyoxyalkylenes, and naturally occurring or synthetically modified
hydrocolloids such as polysaccharides, gums, and modified
celluloses.
[0106] Representative polysaccharides include starch, glycogen,
hemicelluloses, pentosans, celluloses, pectin, chitosan, and
chitin. Representative gums include Arabic, Locust Bean, Guar,
Agar, Carrageenan, Xanthan, Karaya, Alginates, Tragacanth, Ghatti,
and Furcelleran gums. Representative modified celluloses include
methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl,
cellulose, and hydroxypropyl cellulose.
[0107] Preferred hydrocolloids include polysaccharides, such as
starch, glycogen, hemicelluloses, pentosans, gelatin, celluloses,
modified celluloses, pectin, chitosan, and chitin. Modified
celluloses include methyl cellulose, hydroxypropyl methyl
cellulose, carboxymethylcellulose, and hydroxypropyl cellulose. A
most preferred hydrocolloid is a water soluble or swelling
hydrocolloid chosen from the group consisting of polyvinyl
alcohols, powdered pectin, gelatin, methyl cellulose, hydroxypropyl
methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose
and mixtures thereof. In one preferred embodiment, the hydrocolloid
is carboxymethyl cellulose (CMC).
[0108] Suitable swelling colloids are small spherical particles
based on cross-linked polyacrylic acid polymers. Examples of such
materials may be found in U.S. Pat. No. 4,867,748, EP 0 122 344,
and US patent application No. 2004065232.
[0109] Sometimes the skin for attachment of the adhesive device may
be moist or even wet. In these circumstances, the normal adhesives
may not give a sufficient strong and permanent attachment of the
adhesive device. Specialised adhesives useful in these
circumstances are hydrogel adhesives. Such adhesives are based on
hydrophilic polymers and extenders enabling an even uptake of
moisture over the complete skin-contacting surface of the adhesive.
A wide range of compositions of such hydrophilic adhesives exists.
Hydrophilic polyacrylates with high content of acid groups
optionally being partly neutralised, is a major representative in
this group of adhesives. These adhesives may be inherent adhesive
or may be formulated with tackyfiers and extenders to the desired
adhesive properties in dry conditions. When getting moist, the
adhesiveness will increase vastly depending on the formulation as
the uptake of water will transform the adhesive to a more plastic
state. Alternative adhesives are based on polymers like polyvinyl
pyrrolidone, polyvinyl alcohol, polyethylene oxide and the like.
Amphiphilic polymers or polymers which may be chemically
cross-linked by radical polymerisation may be added to improve the
cohesion of the adhesive and extenders like polyethylene glycol,
polypropylene glycol and glycerol are typically preferred.
[0110] Adhesive compositions based on polydimethylsiloxane (PDMS)
have been known since the 1970's. Recently a new subclass of PDMS
based pressure sensitive adhesives has developed namely soft
silicone adhesives. Soft silicone adhesives (SSA's) are two-part,
solventless adhesives based on a cross-linked, silicone elastomeric
structure. The cross-linking is a result of an addition reaction
between a polydimethylsiloxane with vinyl groups and hydrogen
functional siloxanes. The cure reaction is catalysed by a platinum
complex and can occur at room temperature or can be accelerated at
elevated temperature (80 degree C. to 145 degree C.) without the
formation of by-products. Such adhesives are characterised by being
soft and by conforming to the surface structure of the skin,
whereby quickly wetting of the skin is achieved. Because the
viscous component is minimal, the material does not flow and only
small dissipation of the energy occurs when deformation pressure is
applied. The result is an immediate debonding, which happens at
low-peel or shears force, which for some instances may be
advantageous.
[0111] Apart from being excellent skin adhesives PDMS based
pressure sensitive adhesives may have the further properties of
being reusable, since they can be cleaned with tap water and be
reapplied to the skin.
[0112] The pressure sensitive adhesive used for making the adhesive
body of the invention could also be a PDMS gel often described as a
tacky gel. Examples of such commercially available systems are Dow
Corning 7-9800 A&B, from Dow Corning HealthCare US or SilGel
612 from Wacker-Chemie GmbH, Burghausen, Germany, and MED-6340 from
NuSil Technology, Carpinteria, USA.
[0113] The above mentioned pressure sensitive adhesive can either
be used in a non-foamed version or in a foamed version. When gas
bubbles are introduced into pressure sensitive adhesives during the
manufacturing process a lightweight, cellular structure is
produced. Such a pressure sensitive adhesive is more flexible than
the non-foamed versions. (see U.S. Pat. No. 6,326,524 and US patent
application No. 2004065232).
[0114] In general the adhesive body of the present invention has
the desirable elastic, adhesive, moisture transmitting and/or
absorptive properties as well as a high conformability and
flexibility. The flexibility provides a composition that has the
ability to conform to the curvature of body parts while retaining
its adhesive properties even under movements. The high initial tack
at room temperature provides for easy application of the adhesive
device.
[0115] The adhesive device of the invention has on the upper
surface one or more cover layers of any nature, preferably only one
cover layer, to protect against adhesion to linen, clothes and
other environment.
[0116] As a cover material, it is preferred to use a film in the
form of a thermoplastic polymer film or a woven or non-woven layer.
The cover layer is preferably made of an elastic material. The
cover layer is suitably capable of transmitting moisture and may
e.g. be made from polymers such as polyolefin types e.g.
polyethylene, polypropylene or polybutylene, polyamide such as
nylon, polyurethane, polyvinyl acetate, polyvinyl chloride,
fluorinated polyvinyl compound, polyvinylidene chloride, polyvinyl
alcohol, ethylene vinyl acetate, cellulose acetate or other
thermoplastic polysaccharides, polyether block amides like PEBAX,
block copolymers like styrene-isoprene-styrene block copolymers or
ethylene acrylate block copolymers, polyesters such as polyethylene
terephthalate (PET) or derivates thereof and any laminates from
such polymers. The cover layer may suitably be a thin foam layer
like made from polyurethane, polyethylene or polyvinyl acetate.
[0117] The cover layer or film protects the integrated/embedded
microelectronic components as well as the adhesive body against the
environment.
[0118] In one particular embodiment of the invention, an antenna
can be printed directly on the cover layer by means of conductive
ink or printed metal.
[0119] Prior to application to the skin a protective release liner
covers the skin contacting side of the pressure sensitive adhesive
body, in order to ensure that the properties of the adhesive are
preserved and that the adhesive surface is not laid open until just
before the use. The release liner is suitably a siliconised or
fluorinated release liner, such as a siliconised or fluorinated
craft paper, polyethylene, polypropylene or polyethylene
terephthalate film. Suitably, the release liner is a siliconised
polyethylene film, such as medium density polyethylene from the
company Huhtamaki.
[0120] The microelectronic system comprises a number of components,
which may be assembled into one, optionally encapsulated unit,
which is incorporated into the adhesive device of the invention.
The components of the microelectronic sensing system may also be an
assembly of the individual; optionally encapsulated, components
located at different positions in the adhesive device. This
embodiment of the invention covers the situation where the adhesive
devices have all the individual components of the microelectronic
device located in different positions, as well as the situation
where one or more of the components is located at a position
different from the position of the rest of the components which are
located at the same position.
[0121] When the components of the microelectronic device are
located at different positions in the adhesive device, the adhesive
device also has the necessary mechanical or electrical connections
between the components integrated into the adhesive body.
[0122] Thus, according to one embodiment of the invention, the
entire microelectronic system is integrated into the adhesive body
and is completely covered by the adhesive body on all sides.
[0123] According to another embodiment of the invention, the entire
microelectronic system is contained in a recess provided in the
upper surface of the adhesive body facing the cover layer.
[0124] According to another embodiment of the invention, the entire
microelectronic system is contained in a recess provided in the
adhesive bottom surface of the adhesive body.
[0125] In another embodiment of the invention, the microelectronic
system is contained in a through hole in the adhesive body and is
accessible from both the upper surface facing the cover layer and
from the adhesive bottom surface.
[0126] In an alternative embodiment of the invention, one or more
components of the microelectronic system is integrated into the
adhesive body and is covered by the adhesive body on all sides and
the other component(s) of the microelectronic system is located
elsewhere in the adhesive body, the components of the
microelectronic sensing system having the necessary mechanical and
electrical connection to each other.
[0127] According to the above mentioned embodiment of the
invention, one or more components of the microelectronic system may
be integrated into the adhesive body and covered by the adhesive
body on all sides and the rest of the microelectronic system is
contained in one or more a recesses (suitably one recess) provided
in the upper surface of the adhesive body facing the cover
layer.
[0128] Alternatively, one or more components of the microelectronic
system is integrated into the adhesive body and is covered by the
adhesive body on all sides and the rest of the microelectronic
system is contained in one or more recesses (suitably one recess)
provided in the adhesive bottom surface of the adhesive body.
[0129] In another alternative embodiment one or more components of
the microelectronic system is integrated into the adhesive body and
is covered by the adhesive body and the rest of the microelectronic
system is contained in one or more through holes (suitably one
through hole) in the adhesive body and is accessible from both the
upper surface facing the cover layer and the adhesive bottom
surface.
[0130] In still another embodiment one or more components of the
microelectronic system is integrated into the adhesive body and is
covered by the adhesive body, while other components of the
microelectronic system is contained in one or more through holes
(suitably one through hole) in the adhesive body and is accessible
from both the upper surface facing the cover layer and the adhesive
bottom surface, and the rest of the microelectronic system is
contained in one or more recesses (suitably one recess) in the
upper and/or bottom surface of the adhesive body.
[0131] In still an alternative embodiment one or more components of
the microelectronic system is contained in one or more through
holes (suitably one through hole) in the adhesive body and is
accessible from both the upper surface facing the cover layer and
the adhesive bottom surface and the rest of the microelectronic
system is contained in one or more recesses (suitably one recess)
in the upper and/or bottom surface of the adhesive body.
[0132] In another suitable embodiment one or more components of the
microelectronic system is contained in one or more recesses
(suitably in one recess) in the upper surface of the adhesive body
and the rest of the microelectronic system is contained in one or
more recesses (suitably one recess) in the bottom surface of the
adhesive body.
[0133] Where the microelectronic system or components thereof is
placed in the upper surface of the adhesive body, they are suitably
formed with an upper surface following the contours, or shaped to
fit the upper surface of the adhesive body. This may be achieved by
proper encapsulation of the components.
[0134] As mentioned above, the individual components, groups of
individual components or all the components of the microelectronic
system may be encapsulated before they are embedded into the
adhesive body. Encapsulation is chosen when additional protection
of the components from the environment and/or the reverse is
desired, e.g. when already present in the adhesive body or during
the production process leading to integration into the adhesive
body. The encapsulated components of the microelectronic system are
connected to each other via the necessary electrical and/or
mechanical connections.
[0135] In some cases it is required that the micro electronic
system or components thereof are protected from humidity and/or
perspiration in the adhesive since this will initiate corrosion, or
needs shielding from exterior influence for other reasons. In such
cases the micro electronic system or components thereof is
encapsulated.
[0136] A number of encapsulation techniques are known and includes
coating, hot-melt encapsulation, ceramic encapsulation and glass
encapsulations. Other methods for encapsulation of electric
components are known in the art.
[0137] The microelectronic system or components thereof is suitably
encapsulated in a polymer film, a polymer foil, or a polymer
coating or the microelectronic system or components thereof is
moulded into a polymer material, or is encapsulated in a glass or
ceramic material.
[0138] Encapsulation by coating typically involves coating the
component(s) with materials such as epoxy, PDMS (silicone),
acrylate, polyurethane or UV curing resins.
[0139] Encapsulation in silicone, such as PDMS, is particularly
preferred when the microelectronic components is to be placed in a
through hole or a recess in the adhesive body and where it is
desirable to enable easy removal or replacement of the encapsulated
microelectronic component(s), as the silicone surface is easily
released from the adhesive of the adhesive body. Other materials,
which are easily releasable from the adhesive, may also be used for
the encapsulation.
[0140] Hot-melt encapsulation typically involves incorporation of
the microelectronic system or components thereof in a thermoplastic
material by injection moulding. The thermoplastic material used may
be selected from Styrene-block copolymers, polyurethane, ABS
(acrylonitrile-butadiene-styrene copolymer), SAN
(styrene-acrylonitrile copolymer), polyvinylchloride, PDMS, POM
(polyoxymethylene), polystyrene, polyester, polyacrylate,
polyolefines; e.g. polyethylene or polypropylene.
[0141] The components of the microelectronic system require
interconnection. Each system may consist of one or more discrete
components, which need to be assembled mechanically and
electrically. The mechanical or electrical connection may be
established by PCB (printed circuit board), snap locks, thin
flexible PCB, glue etc.
[0142] In one embodiment as described above, all parts of the micro
electronic sensing system is integrated in the adhesive body during
production, meaning that the adhesive device with the
microelectronic system has a disposable nature.
[0143] The adhesive device according to the invention may also be
constructed in such a way that components of the microelectronic
system may be exchanged during the lifetime of the adhesive device
or may reused in a new adhesive device.
[0144] Certain components of the micro electronic system are
integrated into the adhesive body during production whereas the
remaining components is applied to the adhesive device of the
invention afterwards, just prior to attachment on the skin, or
after attachment to the skin. The components applied to the
adhesive body after production of the adhesive body is typically
exchangeable, or reusable.
[0145] The component, which may be exchanged, is for example the
energy source, e.g. the battery.
[0146] In a particular embodiment of the invention the entire micro
electronic system is exchangeable or reusable and may be applied to
the adhesive device just prior to attachment or after it has been
applied to the skin.
[0147] Suitably, the exchangeable component(s) or the reusable
component(s) is encapsulated as described above and forms a
package, which fit a recess or hole in the adhesive body.
[0148] In the case of exchangeable or reusable components they must
have some sort of secure attachment to the adhesive body during
use. Such attachment may be provided by an adhesive, for instance
by the pressure sensitive adhesive of the adhesive body already
present in the indentation, the cavity of the hole in the adhesive
body.
[0149] In this case it may be preferred that the encapsulation
material is a material which does not adhere too strongly to the
adhesive of the adhesive body, see above.
[0150] Alternatively, the package of the encapsulated, exchangeable
or reusable components is attached to the adhesive body via
mechanical couplings to the adhesive body. The above-mentioned
encapsulated package containing the replaceable or reusable
component(s) could thus be fitted into the adhesive body by a snap
lock mechanism.
[0151] The encapsulation function as a housing for the
microelectronic system or components thereof and is suitably formed
of from injection-moulded polymer material, but could in principle
be of any material and any construction.
[0152] The package of encapsulated microelectronic component may
have any suitable shape, suitably three-dimensional shape, fitting
a recess or through hole in the adhesive body. On one embodiment
the encapsulated electronics will have the shape of a rod shaped
capsule with rounded ends.
[0153] As mentioned above, the present invention uses invasive as
well as non-invasive techniques for acquiring physiological data.
In the case of non-invasive measurement one or more metal
electrodes may be used for the skin contact. However, any
conductive material may be used for the skin contact, such as
conducting polymers, conducting hydrogels and electrolytes. In case
of invasive measurements regular needles or micro needles may be
used. Such invasive techniques are already well known today e.g.
for measuring oxygen or blood glucose.
[0154] By combining well-described components, all sorts
microelectronic sensing systems may be designed and incorporated
into the adhesive device of the invention. Examples of systems
suited for embedment in adhesive device are systems suitable for
measurement of biosensor signals, EKG, EMG, EEG, blood glucose,
pulse, blood pressure, pH and oxygen.
[0155] The micro electronic system incorporated into the adhesive
device of the invention typically requires the following
components: Communication components, CPU (central processing
unit), power source, storage components, transducer components,
interconnections and optionally actuator components.
[0156] The CPU (Central Processing Unit) controls and communicates
with the components of the microelectronic system. The CPU handles
the execution of application software, data decisions making (like
data signal processing), A/D conversion, DSP (digital signal
processing), routing, timing, power management, sleep function,
interruption.
[0157] The CPU is the component of the microelectronic system
controlling other components and making the appropriate data
analysis. In general, the more speed and data analysis required,
the more power is needed. Therefore a sleep function is often used
in order to save power. At certain times or if certain events
happen (triggered by a very low power monitoring subsystem) the CPU
wakes up, makes the necessary calculations, communicates with
relevant components and return to sleep mode. Depending on need
very rudimentary CPU to a full-fledged microcontroller can be used
according to the invention.
[0158] The communication components control all communication to
and from the microelectronic system. Suitably, the microelectronic
system is a system enabling wireless communication with a receiver
unit placed at a distance from the adhesive device. However, the
present invention is not limited to wireless communication, such as
RF-wireless communication. Other communication means could be
audible or optical communication means. The component includes the
necessary electronics for achieving this wireless communication but
also the antenna along with the necessary hardware and
software.
[0159] The antenna may be of different shape and form depending on
frequency, power and signal form. Some antennas are useful for
communicating information a few cm, others range several meters.
Examples of antennas are; a coil around a small ferrite core (e.g.
less than 4 mm in diameter, a flat coil with turns (diameter
typically 10 mm or more), single and double wire radio antennas
such as monopole or bipole antennas, and an antenna integrated in
the adhesive.
[0160] An antenna only having few turns and a large diameter e.g.
50 mm may be laminated and integrated into the adhesive body or
printed or directly on the cover layer of the adhesive device. The
antenna is typically made of a metal such as copper or aluminium
but could also be of conductive ink.
[0161] The power source consists of power regulating electronics,
recharge electronics and an energy source, typically an internal or
exchangeable battery. However other means of getting power to the
microelectronic system may be suggested, such as kinetic energy
conversion, fuel cells, isotope radiation, solar cells or via a
radio frequency (RF) link. Further the antenna may be used for
loading energy to the microelectronic system.
[0162] Preferably the power source is a battery, and may be for one
time use or it may be rechargeable.
[0163] The storage component is for storage of the embedded system
software and/or storage of data acquired during operation of the
device. The storage component may be a part of the CPU, a component
of its own or an exchangeable storage device such as FLASH RAM that
can be removed and exchanged.
[0164] The transducer component is a component designed to convert
energy from one form to another. The transducer is typically, but
not necessarily, the sensor or sensing part of the microelectronic
sensing system. A transducer may thus be able to convert for
example a physical input and the transducer will usually but not
necessarily convert this energy into electrical form to be
interpreted by the CPU etc.
[0165] Examples of the physical input a transducer may convert is
acceleration, chemical/gas, flow, humidity, inertia, capacitance,
conductance, conductivity, current, impedance, inductance, pH,
resistance, resistivity, voltage, photo detection, light,
magnetisme, pressure, angular, linear position, velocity,
temperature, sound and mechanical force.
[0166] A tangible representative of the transducer is the detecting
component. The detecting component is typically selected from
electrodes (polar, bipolar), pressure sensors, needles with
electrodes, accelerometers, photo detectors, microphones, ion
specific field effect transistors (ISFET), a NTC (negative
temperature coefficient) resistors, band gap detectors, ion
membranes, enzyme reactors or condensers.
[0167] In one embodiment of the invention the transducer includes a
detector for non-invasive detection, such as an electrode.
[0168] In another embodiment of the invention, the transducer
includes an invasive detector, such as a needle containing an
electrode.
[0169] An actuator is the reverse of a transducer. It converts
energy from one form to another in much the same way as a
transducer but in the reverse order. Usually it converts electric
signals to physical signals. A tangible representative of an
actuator is e.g. electrodes (for instance for neural- or
neuro-stimulation), pumps, injection needles, light emission diodes
(LED) or another light source, loudspeakers, current generators or
chemical synthesizers. A possible use of actuator is at certain
events decided by the CPU to activate an alarm in the
microelectronic system, such as loudspeaker or LED, or to indicate
low battery.
[0170] Thus, the actuator may be used as a component in the system
reacting to the input obtained from the transducer component such
as an alarm (visible and audible), injection pump, valve etc. It
can either be a one time use, a multiple use or continuous use
actuator.
[0171] Many sensing systems are only informative systems
transmitting information about the physical condition of a mammal
and in this case an actuator is not needed.
[0172] The microelectronic system will be modular build in the
sense that in a device for a given application only some of the
components may be needed. Some applications will utilize fewer
components and some applications may use all components. These
components can be fitted into same physical ASIC (application
specific integrated circuit), electrical system or subsystem, such
as but not limited to, PCBs (printed circuit boards), flexible
PCBs, thick film, thin film, or ceramic technologies or the system
or its components may be separately encapsulated
[0173] RFID (Radio Frequency Identification) tags are commercially
available in various sizes, ranges and functionality. When the RFID
reader applies the appropriate field (e.g. an inductive field) the
basic RFID tag return a bit sequence. The sequence is programmed
prior to use. RFID range varies from 1 cm to app. 2 meter for
passive tags (no power source included) to over 100 meters for
active tags (power source included). More sophisticated RFID tags
available have storage components where data can be read or
stored.
[0174] The RFID tag may be incorporated into the adhesive body
either as a standalone part or in combination with other
microelectronic components. Complex microelectronic systems can
easily be made to include various forms of RFID tags without adding
significantly to the complexity or price of the system. In a
complex system the tag can be used as a simple track and trace
component for identification of the product, such as shelf life,
life time, however it can also be utilized for identification for
other systems in sensor networks.
[0175] For a stand-alone solution the RFID tag consist basically of
a RF chip and a coil. Suitable forms of the RFID tag is a RFID tag
encapsulated in a glass housing, a RFID tag encapsulated in
plastic/epoxy (typically pill shaped), a flat RFID tag with coil
and a RF chip laminated between 2 polyimide layers, or a flat RFID
tag with large coil antenna with few turns printed on or in the
adhesive body and with the RF chip interconnected to the antenna
without any further protection/encapsulation.
[0176] These systems can be completely integrated within the
adhesive body during production of the adhesive body.
[0177] The above-mentioned flat RFID tag may be sandwiched between
2 layers of pressure sensitive adhesive during production. As the
RF chip is very small (1 mm.times.1 mm) and the coil is flexible,
no rigid encapsulation is needed. The glass encapsulated RFID tag
has very good chemical resistance and small size to ensure no
discomfort. The RFID tag encapsulated in plastic or epoxy may be of
more complex design and can be added both during and after
production of the adhesive body of the invention.
[0178] The encapsulated RFID tag is a component, which may be
reused, in one or more adhesive bodies. The encapsulated RFID tag
is transferred from one adhesive body to another and thereby reused
time after time, and is ideal for storing person specific data.
[0179] Normally embedded microelectronic systems incorporate some
kind of sensor in its system, however this is not necessary for all
applications.
[0180] The adhesive device of the invention may also be part of a
network of adhesive sensor devices placed on different locations on
the body. These individual adhesive devices may vary in complexity
ranging from a small basic sensor system to more complex system,
depending on location and sensing property. Some adhesive devises
of the network have reduced functionality called RFD (reduced
function devices) whereas other devices are FFD) (Full Function
Devices).
[0181] The FFD devices may function at any topology and be the
coordinator of the Network, or it may be a coordinator that can
talk to any other device. A RFD device is limited to star topology,
it cannot become a network coordinator, it talks only to a network
coordinator and has very simple implementation.
[0182] FFDs may be a dedicated network coordinator acting as
communication Hub, gateway or router within the Body Area Network
(BAN) and handling communication with external unit(s). A
communication Hub or gateway may have large storage capacity and
store data from the sensor network, and when in proximity with
external unit or when otherwise appropriate wireless transmit these
data.
[0183] These hubs are easily integrated within the adhesive body as
no skin contact or actuator is needed, and may be placed
strategically on the body. As hubs will generally be larger and
more centrally placed on the body, it is of great advantage that
the microelectronic hub may be completely integrated within an
adhesive body as this reduces discomfort and visibility.
[0184] In case of person monitoring, the microelectronic system
could incorporate GPS technology. The system is either data logging
the positional data for later analysis or could transmit (e.g. via
the mobile net) position. Such a system within an adhesive could be
place in an inaccessible location on the body.
[0185] A GPS device incorporated in an adhesive body of the
invention need not be a single device in itself, but could be an
add-on to an adhesive devices comprising other microelectronic
systems, so the system can transmit GPS at certain event such as
alarms.
[0186] Thus, the adhesive device may also contain a micro
electronic system where no physical contact between the detector
and the skin of the mammal is necessary. Systems that do not
necessarily use transducers with a detecting element are Network
Hubs, network coordinators, gateways and GPS (Global Positioning
System).
[0187] Accordingly, microelectronic systems useful for use in the
adhesive device of the invention could be:
[0188] A glass encapsulated RFID tag comprising communication
components and a CPU. The glass encapsulated components may
suitably be embedded in the adhesive device as shown in FIG. 1.
[0189] An epoxy or plastic encapsulated RFID tag comprising
communication components and a CPU. The epoxy/plastic encapsulated
components could for example be embedded in the adhesive body as
shown in FIG. 1 or 2.
[0190] A coil antenna and a RFID tag comprising communication
components and a CPU laminated between two polyamide layers. The
system may be embedded in the adhesive body as illustrated in FIG.
1A.
[0191] A coil with few turns and a non-encapsulated passive
read/write RFID tag comprising storage and communication components
and a CPU. The system may be embedded in the adhesive body as
illustrated in FIG. 1A.
[0192] A passive read/write RFID tag comprising storage and
communication component(s) and a CPU encapsulated in an epoxy or
plastic pill. The system may be embedded in the adhesive body as
illustrated in FIG. 2.
[0193] An active read/write RFID tag encapsulated in a
epoxy/plastic pill comprising storage and communication components,
a CPU and a battery. The system may be embedded in the adhesive
body as illustrated in FIG. 1.
[0194] RFID tags of the above-mentioned type are commercially
available.
[0195] The microelectronic system may also be a gateway comprising
storage and communication components, a CPU and a battery
encapsulated in plastic and working as a dedicated network
coordinator for transmission of data to a central unit (CU). Such a
microelectronic system may for example be embedded in the adhesive
body as illustrated in FIG. 1.
[0196] The microelectronic system may also be a system comprising
storage and communication components, a CPU, battery, GPS,
components for wireless synchronisation of real time clock for data
logging of GPS data, optionally encapsulated in plastic, or a
system comprising storage and communication components, a CPU,
battery, GPS, components for wireless synchronisation of real time
clock for data logging of GPS data, mobile net for data logging and
transmission of data and position to mobile phones, optionally
encapsulated in plastic. These systems may also be embedded in an
adhesive body as illustrated in FIG. 1.
[0197] The adhesive device according to the invention may also be
used for applications where body implants are applied electrical
power and electrical data communications via wireless means across
the skin barrier (trans-cutaneously). In these cases it is
important to fix the adhesive device at an exact spot on the skin
surface for long periods of time with minimal annoyance or
inconvenience for the person carrying the device.
[0198] A typical example of wireless trans-cutaneous power transfer
and electronic data communication is in implanted nerve stimulators
for people who suffer from disable control of their muscles in the
lower part of their leg (the drop foot syndrome). The drop foot
stimulator is implanted inside the leg and has direct contact the
nerves controlling the relevant muscles. The implant is typically
powered wirelessly by means of an electromagnetic coupling between
a coil or an antenna inside the leg and a coil or antenna placed
nearby on the outside of the body on the skin surface.
[0199] The coil or antenna is connected to the electronics
providing the needed power and control signals. The timing for the
simulation signal is normally controlled by a pressure sensitive
switch at the heel of the person or in his shoe. Often the
transmission of the signals from the switch to the simulator placed
on the skin of the leg is wireless.
[0200] These drop foot simulators will be substantially improved by
using the adhesive device described in the invention. It enables
reliable power and data transfer because of the very stable
fixation of the external part of the simulator on the skin surface
for long periods of time with minimal inconvenience. Further it can
also enable better long-term fixation of the switch placed on the
foot.
[0201] Thus, in one embodiment, the microelectronic system is
useful for nerve stimulation and comprises storage and
communication components, a CPU, power source and transducer for
transmitting data and power to implant for nerve stimulation. The
system may suitably be embedded in the adhesive body as illustrated
in FIG. 3.
[0202] In another embodiment, the embedded microelectronic system
is useful for surface electromyography (sEMG) or invasive
electromyography. In both cases the transducer is a relatively
simple 2-3 electrode device. The signal measured is a direct
voltage generated by a muscle or a muscle group. In order to
understand this signal it must be analysed either by the
microelectronic system or stored for future analysis.
[0203] The data collected are transmitted to a Central Unit (CU)
either when relevant, when certain events occurs or at certain time
intervals. The CU is suitably a portable hardware device with
wireless reception/sending capability, such as but not limited to a
PDA (personal digital assistant), a mobile phone or other dedicated
hardware.
[0204] The transducer is suitably designed to overcome or neglect
the difference from time to time of the surface resistance of the
skin. Dry skin has resistance of e.g. 500 kOhms and sweaty skin
could be as low as 500 Ohms. This problem may be over come by
utilizing a high impedance amplifier, where impedance is above 500
MOhms. The transducer may be designed to activate other system
components on the first skin contact thereby ensuring longer
lifetime.
[0205] The central processing unit (CPU) handles the amplification
(e.g. .times.30-.times.1000) of the transducer signal, typically by
differential instrumentation amplifier with rejection of common
modes (unwanted signals/noise that is common for both electrodes),
filtered either analogically or digitally. The CPU handles
conversion of analogous signal to digital signal. Signal analysis
such as rms (root mean square), FFT (Fast Fourier Transformation)
and digital filters combined with software are employed to achieve
a data decision on certain events.
[0206] Furthermore the CPU could employ timers or sleep mode, so
measurement is only during certain events or only a fraction of
each second or other time period, thereby saving power.
[0207] The microelectronic system also comprises storage components
for storage of Software and EMG data storage in those cases where,
only some or no data are transmitted wireless during data
acquisition. These data may be transmitted at a later time.
[0208] The power source is thought to be either a single use
battery as the CPU ensures long lifetime due to power down in
inactive periods, or a rechargeable battery. The rechargeable
battery is recharged either through a RF link or by placing the
microelectronic system in a recharge cradle when the system is not
in use. Several weeks of lifetime after activation are possible
with one battery or charge up.
[0209] Data is transmitted to Central Unit with a protocol or
method that can ensure no corruption of data. Furthermore after
activation battery life condition and/or a data burst are
transmitted in order validate operational status of the system. On
request the system will transmit storage data.
[0210] The microelectronic system for electromyography may
optionally include an actuator, which at certain events decided by
the CPU activates an alarm in the microelectronic system, such as
loudspeaker or LED. The event activating the actuator could also be
low battery.
[0211] According to this embodiment of the invention the various
components are interconnected mechanically and electrically and may
be encapsulated into a module. However, various components may also
be integrated separately into the adhesive body. These components
could be but is not limited to, the battery, the antenna and the
actuator.
[0212] The various components could also be mounted on PCB (printed
circuit board) or flexible PCB and coated with a protective layer
and directly be embedded in the adhesive.
[0213] Thus, in a specific embodiment of the invention, the
microelectronic system is a system useful for electromyography and
comprises a transducer (2-3 electrodes and an Instrumentation
Amplifier), a CPU (.mu. Controller e.g. ATMEGA 128L), a power
source (e.g. battery), communication (e.g. to CU) and storage
components and an actuator (LED). This system may be embedded in
the adhesive body as illustrated in FIGS. 3 and 3A.
[0214] During sport or fitness exercise different or several of the
same microelectronic systems may be used in combination.
Furthermore several transducers could be used in the same adhesive
device.
[0215] A fitness sensor network may thus consist of:
[0216] Adhesive devices with a muscle activity (sEMG) sensor, one
for both sides of the body (arms, legs etc). The electromyography
system could be designed in such a way to determine the fatigue of
the muscles and indicate when muscle growth is optimal or when
exercise has no benefit. Frequency analysis of the sEMG signal may
be used to achieve the desired output of the measurements.
Typically the adhesive devices are placed on muscle groups that are
actively exercised.
[0217] Two or three adhesive devices of the invention comprising a
Heart Rate (ECG) sensor system of for monitoring heart beat and
heart pulse shape.
[0218] Adhesive devices comprising microelectronic systems for
determining levels of fatigue poisons in muscles.
[0219] A sensor Hub/gateway centrally located on the body for
storing and routing signals to either a central unit or directly
communicating with fitness hardware.
[0220] The microelectronic system may be reusable from one fitness
session to another with change or charge up of battery.
[0221] Thus, the adhesive device according to the invention may
suitably be used for measuring physiological conditions that relate
to diseases, health care surveillance, rehabilitation, sports
medicine or general surveillance. Typically applications will be
for patients at risk for instance when suffering from weak heart,
epilepsy, fever and fever spasms, diabetes, apoplexy,
arteriosclerosis and muscular dystrophy. Applications may be
associated with general monitoring for optimising medication, for
registering of the disease or for alarming. Other applications will
be for rehabilitation in respect to monitoring of physical work,
muscle strength, lung capacity, or in the sports medicine for
determination of work and repetition, acceleration, heart rate,
muscular stress and strength, orientation etc. Yet other
applications will be for surveillance of objects or mammals in
motion. Mentally disable patients or individuals like elderly
people suffering from dementia will be typical for such
applications.
[0222] The adhesive device according to the invention will
preferably be wireless as this will be meaningful in respect to
obtaining as smooth a shape and surface of the device as possible
and still achieving the protection of the microelectronic system.
In certain occasions it may, however, be important to be able to
interconnect the devices by wires. This may especially be an option
when the microelectronic system is divided in two parts each being
present in an adhesive device as defined in the invention.
[0223] The microelectronic sensing system or the components thereof
may be incorporated into the adhesive body either during production
of the adhesive body, or after production of the adhesive body,
e.g. just prior to application of the adhesive device to the skin,
or after application of the adhesive device to the skin.
[0224] As described above, parts of the adhesive device such as
parts of or the entire microelectronic system may be exchangeable
or reusable.
[0225] Thus, in one aspect of the invention the present invention
discloses a device comprising at least an adhesive element and a
power source element, said device adapted to attach an electronic
circuit, such as the microelectronic system, to a surface and to
power said electronic circuit, wherein at least one of the device
elements is releasable attachable to the electronic circuit; the
power source element is electrical connectable to the electronic
circuit; and the adhesive has at least a first area for adhering to
the surface.
[0226] Such a device as described may attach and power the
electronic circuit to a surface, such as e.g. the skin of a mammal,
for a specific purpose. When the specific purpose is fulfilled the
device and the electronic circuit is removed from the surface and
the device is separated from the circuit and disposed. Thus, the
elements forming the device, which are relative cheap compared to
the electronic circuit, is disposed while the electronic circuit
may be reused together with a new device according to the invention
for attaching the electronic circuit to a surface and powering the
circuit. Advantageously this allows reducing costs considerably
while also protecting the environment as more components are reused
than done until now.
[0227] By the terms `releasable attachable` and `releasable
connectable` it should be understood that the device and the
electronic circuit may be temporarily attached in such a way that
the risk of unintentionally separating them is minimal. However the
device and the electronic circuit should be attached in such a way
that they may be separated if desired.
[0228] Furthermore, by the term `electrical connectable` it should
be understood that the power source element and the electrical
circuit is arranged in such a way that an electrical current may be
transmitted between them. This may for example be done by use of
standard electrical contacts, typically made of copper
alternatively gold or silver plated, or the electrical connection
may be provided in a wireless manner where the power source induces
a current in the electrical circuit.
[0229] Typically the electronic circuit is a microelectronic system
formed of a number of microelectronic digital components and/or
analog components connected with appropriate wiring. The components
are typically arranged on a print circuit board whereon the proper
traces and tracks are etched, electroplated, or otherwise provided
on the board. Digital components may for example be
microprocessors, storage elements such as RAM-blocks and analog
components may for example be resistors and capacitors provided on
the print board.
[0230] In one embodiment the power source element is attached to
the adhesive element and the adhesive element has a second area for
adhering to the electronic circuit.
[0231] By attaching the power source element and the adhesive
element to each other only one physical part is provided, avoiding
that the user has to keep track of both the power source element
and the adhesive element and spend time on applying both. Thus a
small and discrete device, which is convenient for the user, is
provided. Furthermore the electronic circuit may be adhered to the
adhesive element for improved handling, as only one unit will have
to be manipulated when applying the electronic circuit to the
surface.
[0232] Advantageously a first peel force between the second area
and the electronic circuit is smaller than a second peel force
between the power source element and the adhesive element. This
allow for easy separation of the microelectronic circuit from the
device after use.
[0233] To further ensure that the power source element and the
adhesive element do not separate from each other the power source
element may at least partly be contained in the adhesive
element.
[0234] By `contained` it should be understood that the power source
may be fully or partly embedded in the adhesive. When fully
embedded only electrical contacts are exposed through the adhesive
or thin flexible electrical wires are embedded in the adhesive
extending from the power source to an outer surface of the adhesive
where it may be brought into contact with the electronic circuit.
Furthermore, within the meaning of the term contained the power
source may also be partly embedded in the adhesive thereby exposing
a larger section through the adhesive. This allows for a large
contact surface between the electronic circuit and the power source
while at the same time being safely attached to the adhesive.
[0235] To protect the different parts of the electronic circuit it
will typically be encapsulated, for example by coating it in
silicone or hot-melt polymers. The encapsulation may for example be
formed as a housing containing at least a part of the electronic
circuit. In one embodiment the housing may be formed of a proximal
housing part and a distal housing part. The device is adapted to be
releasable connectable to said housing.
[0236] A number of encapsulation techniques are known and includes
coating, two component polymer, hot-melt polymer encapsulation,
ceramic encapsulation and glass encapsulations. Other methods for
encapsulation of electric components are known in the art.
[0237] The microelectronic system or components thereof is suitably
encapsulated in a polymer film, a polymer foil, or a polymer
coating or the microelectronic system or components thereof is
moulded into a polymer material, or is encapsulated in a glass or
ceramic material.
[0238] Encapsulation in silicone, such as PDMS, is particularly
preferred when the microelectronic components are to be placed in a
through hole or a recess in the adhesive body and where it is
desirable to enable easy removal or replacement of the encapsulated
microelectronic component(s), as the silicone surface is easily
released from the adhesive of the adhesive body. Other materials,
which are easily releasable from the adhesive, may also be used for
the encapsulation.
[0239] In order for the adhesive element to be easily released from
the housing after use the housing may advantageously be made from a
material, or coated with, which allows the housing to easily
release. Such a material may for example be a silicone, which often
is used for release liners in different adhesive applications.
[0240] In yet another embodiment the at least one power source
element is adapted to be received in a recess formed in the distal
housing part. At least one electrical contact is provided in the
distal housing providing electrical connection between the power
source element and the electrical circuit.
[0241] By providing a recess as described above the power source
element is protected from being displaced and thereby losing
electrical contact with the circuit. The recess also creates a
flush assembly when the power source is placed therein giving it a
smooth surface which will not get caught as easy as from a surface
where the power source would protrude.
[0242] Many types of electronic circuits having many different
applications and which is powered and attached to a surface may be
used with the device according to the invention. The device may
after use be disposed but the electronic circuit may be reused. In
one embodiment the device is thus adapted to be releasable
connected to electronic circuit, which is a sensor circuit, said
sensor circuit is to be attached to the body surface of a mammal,
typically the skin.
[0243] By the term `sensor` or `sensoring` it should be understood
that a parameter of the ambient environment of the electronic
circuits is detected by the sensor circuit. Such parameters may
among many for example be temperature, humidity, electrical signal,
electrical fields, light, noise, biosignals and magnetic
fields.
[0244] Thus, the invention also relates to a sensor assembly
adapted to be attached to the body surface of a mammal, comprising;
a sensor circuit, comprising a number of electrical components; at
least one power source element for powering at least one of the
electrical components; at least one adhesive element for attaching
the sensor assembly to the body surface of a mammal; and that at
least one of the power source element and the adhesive element is
releasable connected to the sensor circuit.
[0245] Thus, the sensor assembly provides the advantages as
disclosed above when different elements are disposable, such as the
device comprising the power source and the adhesive element, and
others are reused, such as the electronic circuit.
[0246] In one embodiment of the sensor assembly the sensor circuit
is at least partly contained in a housing where the housing is
formed of a proximal housing part and a distal housing part.
Advantageously a sensor assembly may be provided where a first peel
force between the adhesive and the housing is smaller than a second
peel force between the adhesive and the battery. This allows for
easy separation of the sensor circuit from the adhesive and power
source elements.
[0247] Typically the sensor assembly will comprise at least one
transducer attached to a proximal surface of a proximal part.
Together with a distal part the proximal part makes up a housing,
as described earlier, for protecting at least a part of the sensor
circuit. This transducer will transform different physiological
signals into electrical signals. Such transducers may for example
potentiometric, caliometric, conducmetric, chemomechanical or
optical.
[0248] To prevent that the power source accidentally moves out of
electrical contact with the sensor circuit a recess may be formed
in the distal housing part, the recess is adapted to receive the at
least one power source and that at least one electrical contact is
provided in the distal housing providing electrical connection
between the at least one power source and the electrical
components. The recess thus protects the power source from outside
movement, for example when the adhesive moves due to movement of
the surface whereto the sensor assembly is attached. Additionally,
by protecting the power source from outside movement the electrical
connection between the power source and the microelectronic circuit
is also protected from disconnection.
[0249] In another aspect the present invention relates to the use
of a device comprising an adhesive element and a power source
element, and where the device is used for attaching an electronic
circuit to a surface and to power said electronic circuit, wherein
said electronic circuit is releasable connectable to the adhesive
element and the power source element.
[0250] Many sensors are connected to the monitoring systems with
wires. The disadvantage of such a system is that the patient does
not have freedom to move since the wires are attached to the
sensors on the body and connected to a monitoring system. Whenever
the patient wants to move he must be careful not to dislodge any of
the wires attached to the sensors, and he must further pick up the
monitoring system and carry it along.
[0251] Furthermore, an isolated power source, such as a battery,
where no external wiring is necessary is preferred. Such isolated
power source elements preferably used with the present invention
are well known in the art.
[0252] In general, batteries may be divided into primary batteries,
which are single use and secondary batteries, which are
rechargeable.
[0253] Primary batteries are produced in various types based on
different combinations of anode, cathode and electrolyte materials.
Common chemistries for primary batteries include zinc-carbon, zinc
chloride, alkaline manganese dioxide, silver oxide, zinc/air and
lithium in these combinations: lithium/sulfur dioxide (Li--SO2),
lithium/thionyl chloride (Li--SoCL2), lithium/manganese dioxide
(Li--MnO2), lithium/carbon monofluoride (Li--(CF)n), lithium/copper
oxide (Li--CuO), and lithium/iodine (Li--I2).
[0254] Secondary batteries are rechargeable and are typically based
on Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH) or
Lithium-ion technologi. Secondary batteries usually have more
active chemistries that need special handling and disposal.
[0255] Many battery sizes and cell casing exist, including standard
cylindrical cells, multi-cell batteries, coin cells, pouch cells
and thin film batteries.
[0256] Standard cylindrical cells and multi-cell batteries are
known from common household appliances, e.g. flash lights and
remote controls. This group includes the well known sizes AA, D, C,
and 9V rectangular.
[0257] Coin or button cells are typically small, round and a few
millimetres high. This group is often found in watches, hearing
aids and memory backup. Since they are based on solid-state
cathodes, these systems are considered very safe.
[0258] Duracell, Panasonic, Sony and Energizer are some of the
major manufacturers of standard and coin cell batteries.
[0259] Alternatively, using pouch casings along with Lithium
Polymer cells with solid electrolytes can provide another type of
batteries. This provides a low cost bendable construction. The
batteries are characterized by a high energy density in addition to
being re-chargeable. The solid electrolyte permits safer,
leak-proof cells. The foil construction allows very thin and
lightweight cell designs.
[0260] Bullith Batteries manufactures flexible batteries based on
this technology.
[0261] Yet another type of batteries are thin film batteries, which
are based on the printing of solid state lithium polymer chemistry
on a variety of substrates. They can be printed directly onto
plastics, thin metal foils or paper resulting in ultra thin and
flexible power sources. The batteries can be made in any shape or
size, but are generally limited in energy storage and current
capacity. The batteries are very safe as they contain no caustic
chemicals, cannot overheat, explode or cause electrical shock.
[0262] The Israeli company Powerpaper are selling products based on
thin film technologies. Other companies producing this type of
batteries are Oak Ridge Micro Energy Inc. and Infinite Power
Solutions.
[0263] In one embodiment the adhesive element is formed as a
three-dimensional adhesive body as described earlier, i.e. the
adhesive element has a considerable thickness, typically several
times thicker than the backing layer whereon it is applied.
[0264] The pressure sensitive adhesive making up the
three-dimensional adhesive body is suitably a mouldable
thermoplastic or chemically curing pressure sensitive adhesive
having a flexibility enabling the adhesive device to conform to the
curvature of body parts while retaining its adhesive properties
even under movements.
[0265] The backing layer may furthermore function as a cover layer,
where said backing/cover layer is provided to function as base
wherein the adhesive is applied and to protect the adhesive from
the outer environment, e.g. against adhesion to linen, clothes or
moisture.
[0266] Furthermore, an electromechanical display system may be
applied to the cover layer. Such display system may allow the user
to test the charge of battery, either before adding the powered
adhesive to a microelectronic system and during use.
[0267] Simple battery indicators known in the art may thus be used.
For example a foil consisting of two contact electrode and a
conductive thermochromic ink, typically liquid crystals or
leucodyes, may be used.
[0268] When for example using a common coin battery, one electrode
is in contact with the anode of the battery and the other electrode
in contact with cathode of the battery. By pressing the contact
device on top of battery the battery test circuitry is closed and
the thermochromic ink will light up indicating battery status.
[0269] The cover layer or film protects the integrated/embedded
microelectronic components as well as the adhesive body against the
environment.
[0270] The adhesive device of the invention may be constructed in a
number of ways, as it will be described in more detail below.
Common for all constructions are that the three-dimensional
geometries provide good protection for the microelectronics and at
the same time give the device as smooth a surface as possible.
Especially the shaping of the edges of the device need paid
attention, otherwise linen will easily stick to them and cause
rolling. Therefore the outer rim of the adhesive device with the
embedded micro electronic system must be shaped to thickness less
than half of the thickest part of the device, normally the central
part comprising the microelectronic electronic system.
DETAILED DESCRIPTION OF THE DRAWINGS
[0271] FIG. 1 shows a die section of the shape of a typical
representative of the adhesive device according to the invention.
CT relates to the maximal thickness of the device and PT to the
thickness in the periphery of the device. The device does not
necessarily need to be shaped symmetrically.
[0272] FIG. 2 has a box showing the part of the adhesive device,
which is illustrated in FIGS. 3-12. As illustrated in FIG. 2 the
electronic parts 101 are embedded in an adhesive body 102 with a
cover layer 103 and a release liner 104.
[0273] In one embodiment of the invention, all the electrical
components are assembled in one unit, which is embedded in the
adhesive body and is covered on all sides with the pressure
sensitive adhesive, essentially making it a disposable pad. As
illustrated in FIG. 3 an assembly of electronic parts 101 are
embedded in an adhesive body 102 with a cover layer 103 and a
release liner 104.
[0274] FIG. 4 illustrates that the components of the
microelectronic sensing system may be positioned at different
locations within the adhesive body, provided there is the required
mechanical or electrical connection between the components. All
components are completely embedded in the adhesive body and are
covered on all sides by the pressure sensitive adhesive of the
adhesive body.
[0275] The integration of all microelectronic components within the
adhesive body is useful for cheap throw away one time one use
devices. Because of the short usage time of the adhesive device the
electronics need little or none extra protection, such as
encapsulation. The adhesive body itself acts as protection of the
microelectronic components.
[0276] Even though all the components of the microelectronic system
are covered on all sides with the adhesive body, several sensing
applications (humidity, optical or chemical/gas) are still
possible.
[0277] Systems, which may be covered on sides, may also be a RFID
TAG, a Network Hub, a network coordinator, a gateway, or other
systems capable of collecting, communicating and/or transmitting
data. These systems would often need some kind of activation to
start the system, such as a pressure contact or magnetic contact to
overcome the need for large shelf life compared to the active
period.
[0278] FIG. 5 illustrates an embodiment of the invention where the
microelectronic system is embedded/applied into a recess in the
adhesive body. The recess is positioned in the upper surface of the
adhesive body. The microelectronic system may be embedded/attached
during fabrication of the adhesive body, just before or after the
adhesive device has been attached to the skin. According to this
embodiment of the invention, the microelectronic system may be
reused.
[0279] FIG. 6 shows a microelectronic system analogous to the
system of FIG. 5, however, in FIG. 6 the system consists of two
parts. One part, the upper, is exchangeable of reusable and the
lower is embedded in the recess of the adhesive from start. The
upper part may for instance be the power supply.
[0280] FIG. 7 illustrates an embodiment where some components of
the microelectronic system is embedded within the adhesive device
during production and some components are applied in a recess in
the upper surface of the adhesive body, i.e. are exchangeable or
reusable. According to the invention one or more component(s) may
be embedded within the adhesive body and one or more component(s)
may be present in a recess at the surface of the adhesive body. The
necessary mechanical or electrical connection between the
components are also embedded in the adhesive body. Although the
figure only illustrates one, there may be two or more recesses in
the upper surface of the adhesive body and there may be two or more
components integrated into the adhesive body.
[0281] The exchangeable parts in the recess may be locked in the
recess by the adhesive properties of the pressure sensitive
adhesive in the recess. In an alternative the microelectronic
components in the recess is encapsulated in a coupling or plug
designed to fit into a lock, such as a snap lock, present in the
recess.
[0282] FIG. 8 illustrates an embodiment of the invention where the
microelectronic system is embedded/applied into a recess in the
adhesive bottom surface of the adhesive body. The microelectronic
system is embedded/attached during fabrication of the adhesive
device or just before attaching the adhesive device to the skin.
This system is typically used where it is required that some of the
components of the system are in contact with skin either
non-invasively or invasively.
[0283] FIG. 9 illustrates en embodiment where some components of
the microelectronic system is integrated within the adhesive device
during production and some components are applied in a recess in
the lower surface of the adhesive body, i.e. are exchangeable.
According to the invention one or more component(s) may be
integrated into the adhesive body and one or more component(s) may
be present in a recess at the surface of the adhesive body. The
necessary mechanical or electrical connection between the
components are also integrated into the adhesive body. Although the
figure only illustrates one, there may be two or more recesses in
the bottom surface of the adhesive body and there may be two or
more components integrated into the adhesive body at different
locations.
[0284] FIG. 10 illustrates an embodiment where some components of
the microelectronic sensing system is integrated into the adhesive
device during production and some components are applied in a
recess in the bottom surface of the adhesive body, i.e. are
exchangeable or reusable. According to the invention one or more
component(s) may be integrated separately into the adhesive body
and one or more component(s) may be present in a recess at the
surface of the adhesive body. Although the figure only illustrates
one, there may be two or more recesses in the bottom surface of the
adhesive body.
[0285] This construction is suitable where the transducers or
actuators utilize skin contact or skin penetration (e.g. electrodes
and needles), whereas the rest of the microelectronic system may be
embedded in the adhesive body (batteries, antenna, electrode, A/D
converter, amplifier). This configuration also has several
production advantages.
[0286] Thus, FIGS. 8, 9 and 10 illustrates a construction where the
exchangeable part e.g. the battery, is attached to the adhesive
part facing the patient. Prior to mounting the adhesive sensor
device on dermis of the mammal the protective release liner is
removed, the exchangeable battery is coupled to the rest of the
microelectronic system enabling the electronic system to function.
Thereafter the adhesive part of the device and the whole
construction is mounted on the dermis of the patient.
[0287] After use the exchangeable part e.g. the battery, is
replaced and the adhesive device may be used in the context of a
new monitoring of the patient.
[0288] In order to be able to remove the battery following
detachment of the adhesive device, the inner part of the recess in
the adhesive device could be coated with a PDMS curable coating or
other non-adhesive coating; this operation will facilitate the
exchange of the battery.
[0289] The battery as well as other exchangeable components, such
as the chip, may be present in a recess in the bottom surface of
the adhesive body. According to this embodiment, it may be an
advantageous to have the exchangeable microelectronic parts
contained in a capsule, e.g. embedded in an injection-moulded
capsule.
[0290] Just prior to mounting the capsule containing the
microelectronic components the release liner is removed and the
exchangeable capsule is attached to the adhesive body in the recess
of the adhesive construction. The microelectronic components may be
coated with curable PDMS or other non-adhesive coating in order to
facilitate detachment of the exchangeable capsule.
[0291] When the microelectronic components have a longer life than
the adhesive body, the cheap components, such as the transducer,
the antenna or the power source, may be integrated into the
adhesive body and the components that may be reused are placed in a
recess before use.
[0292] Another application is where customised preparation or
programming of the system is done prior to application.
[0293] The features and applications described in connection with
FIG. 3 apply equally well to the embodiment illustrated in FIG. 5
and vice versa.
[0294] FIG. 11 illustrates the integration of a microelectronic
system within a through hole in the adhesive body providing access
to the microelectronic system from both the upper surface and the
bottom surface of the adhesive body. The application of the
microelectronic system is possible both during
production/fabrication of the adhesive or just prior to application
to the skin, and/or after application to the skin.
[0295] FIG. 12 illustrates a system where two components or
assemblies of components of the microelectronic system are
connected in some way. One of the components may be integrated
during production, whereas the other is applied afterwards.
[0296] Alternatively, the components or assemblies of components
are applied afterwards. This is useful where different lifetime
make is feasible to exchange electronic components at different
times, such as battery or transducer. Mechanical and/or
electrically interconnection schemes such as snap locks or plugs
are advantageous in this configuration.
[0297] The system illustrated in FIG. 4 is useful where skin
contact and simultaneous access to electronic components from the
upper surface is needed. One or both subsystems can be reused.
[0298] The features and applications described in connection with
FIGS. 5 and 8 applies equally well to the embodiment illustrated in
FIG. 11 and vice versa.
[0299] FIGS. 13-18 illustrates an embodiment of the invention where
an antenna, a central processing unit, a battery and electrodes are
embedded in an adhesive device.
[0300] FIG. 13 illustrates the two-dimensional shape of the device
indicating a cross-section by A-A.
[0301] FIG. 14 illustrates the position of the antenna 109 placed
in the outer part of the adhesive device and being connected to the
central part of the microelectronic system.
[0302] In FIG. 15 the third dimension is shown in cross-section
along the line A-A in FIG. 13. The circle B from the rim of the
device is further magnified in FIG. 16 and the circle C of the
centre is likewise magnified in FIG. 17.
[0303] FIG. 16 shows more in detail the building of the antenna
lying embedded in the adhesive. This clearly shows the cover film
103 and the release liner 104 for the adhesive 102.
[0304] FIG. 17 shows the position of the central part of the
microelectronic system 1 with a battery 105, a CPU 106 and
protruding the adhesive the electrode 107. The battery and the CPU
is enveloped in a transparent silicone rubber 108.
[0305] Finally FIG. 18 illustrates the adhesive device in a
perspective.
[0306] There are other ways of constructing an adhesive device
having an embedded micro electronic system, that fulfils the basic
requirement of a three-dimensional construction and the drawings
may thus not be construed as limiting.
[0307] One special advantage of the invention is the simple and
inexpensive way of preparing an adhesive body having a
three-dimensional shape from a pressure sensitive adhesive.
[0308] As mentioned above, the pressure sensitive adhesives are
either a thermoplastic pressure sensitive adhesive or it is a
chemically curable adhesive that has the ability to be moulded into
a three-dimensional shape.
[0309] The thermoplastic pressure sensitive adhesive may typically
enter a fluid condition and achieve a moderate viscosity at above
100-120 deg C. i.e. above the glass transition temperature of the
composition, which makes it easy to mould the adhesive composition
to the desired shape. One example may be direct moulding. In a
first step the cover layer is provided in the desired shape at
temperatures just below the glass transition temperature of the
cover film and then the necessary amount of adhesive is filled the
into the mould to fill up the mould. The filling of the mould may
be in two steps whenever appropriate. This will allow partly
filling with the molten adhesive in a second step, placing the
electronic parts in a third step and eventually filling and
covering the electronic parts with the remainder of the adhesive in
a fourth step. As a last step a release liner is applied and then
the adhesive device is punched out of the mould.
[0310] Alternatively the adhesive laminated with the cover film may
be processed through compression, pressing or moulding into the
desired geometry or shape at elevated temperature, but slightly
below the glass transition temperature of the adhesive. Optionally
the microelectronic system may be placed between two layers of
adhesives and then moulded. The moulding is performed in the press
at elevated temperature and if desired with the microelectronic
system placed in the mould preferably in the centre of the
mould.
[0311] In the special embodiment where exchangeable or reusable
components are a part of the adhesive device, a female and a male
part of a moulding shape is required.
[0312] In another embodiment of the invention curable pressure
sensitive adhesive is cast in the desired shape. The casting may
follow the same principles as of above allowing a partial filling
step of the mould with the cover film, applying the electronic
components and thereafter complete the filling of adhesive in the
mould and finally concluding with placing the release liner, curing
if necessary and die cutting.
[0313] Another method is moulding by compression of adhesives
having high or very high viscosity. A primary layer comprising a
pressure sensitive adhesive e.g. a hydrocolloid containing block
copolymer on a cover film taken from a roll enters the processing
equipment as a first step, the pre-assembled, optionally
encapsulated micro electronic components is placed with the
appropriate distance in a second step, in a third step, a secondary
layer of the same or another pressure sensitive adhesive is
laminated to the first layer of pressure sensitive adhesive
enclosing the microelectronic part between the layers, in a fourth
step said laminate is formed in a hydraulic press into a shape
containing multiple projections centred upon the microelectronic
part and in a fifth step the individual projections are die cut to
final devices.
[0314] The pressure sensitive adhesive devices can be produced
according to a continuously process as described in U.S. Pat. No.
6,726,791.
[0315] FIGS. 19, 20 and 21 shows one embodiment 1 of a sensor
assembly according to the invention. FIG. 19 shows the sensor
assembly in an exploded view. FIG. 20 shows the assembly seen in
section along line XX-XX in FIG. 19 when the sensor assembly is
assembled. FIG. 21 shows the sensor assembly seen from the skin
side, also referenced to as the proximal side, i.e. the side of the
sensor assembly, which is to be attached to the skin.
[0316] The sensor assembly 1 consists of a sensor device 2 and
housing element 3 which contains a microelectronic circuit 4. The
sensor device 2 is made up by an adhesive element 5 and a power
source element in the shape of a coin cell battery 6.
The housing element 3 is made up of a distal part 7 and a proximal
part 8. A recess 9 is formed in the distal part. The recess has a
circumference, which is slightly larger than the circumference of
the coin cell battery allowing the coin cell battery to be received
in the recess.
[0317] In the recess there is provided two electrical contacts 10a,
10b for electrically connecting the microelectronic circuit 4 and
the battery 6 when the battery is placed in the recess. The
microelectronic circuit is made up of a number of components
arranged on a print board 11. Every component will not be described
herein as the circuit is well known in the art and as such not a
part of the invention in itself. In general it can be mentioned
that the circuit comprises an antenna 12 formed by a number of
windings of a conductive material printed on the print board. The
antenna transmits and receives data from a central unit placed
within communication range. The central unit may for example be a
personal computer which gathers data from the sensor assembly. The
data is then processed according to known processes and
algorithms.
[0318] The antenna 12 is connected to a microprocessor 13, which
receives signals from a first transducer 14 and a second transducer
15. The first and second transducer extends from the print board
through the proximal part and terminates on the proximal surface of
the proximal part. Thus, when the housing is placed on the skin the
first and second transducer contacts the skin surface. In order to
reduce interference between the first and second transducer a
barrier element 16 is placed on the proximal surface of the
proximal part between the two transducers. The barrier element is
formed of a dielectric material and is a well known measure in
order to avoid so-called cross talk, typically causing unwanted
interference, between two electronic components.
[0319] When used the battery is placed in the recess, whereby the
battery is placed in contact with the electrical contacts 10a, 10b
and thereby powers the microelectronic circuit. The adhesive
element is then applied on the distal side of the distal part of
the housing and the distal side of the battery. This secures the
battery in the recess and connects the adhesive element, the power
source element and the housing element into a sensor assembly.
[0320] As can be seen the adhesive element has a circumference
which is larger than the circumference of the housing which
provides an adhesive proximal surface 17 which can be applied to
the skin surface of a person or other mammal.
[0321] When the sensor assembly later is removed the adhesive
element is separated from the housing element the battery is
removed along with the adhesive element as the distal surface of
the battery is adhesively attached to the adhesive element. The
adhesive element and the battery can then be disposed and the
housing element may be cleaned and stored for later use.
[0322] The adhesive element is covered by a cover layer 18 in order
to protect the adhesive element from adhering to unwanted surfaces,
such as the inside of worn clothing articles. The cover layer 18
also functions as backing layer whereon the adhesive material 19 is
disposed during production.
[0323] FIG. 22a shows another embodiment 30 of a device according
to the invention. FIG. 22b shows a section of FIG. 22a in an
enlarged view. The device is made up by a two-dimensional adhesive
element 31 and a power source in the shape of a coin cell battery
32 adhered to the adhesive element.
[0324] The adhesive element is formed of a backing layer 33. On the
proximal side of the backing layer there is provided a first
adhesive layer 34, which is covered by a first release liner 35.
The distal side of the backing layer there is provided a second
adhesive layer 36 to which the battery is adhered. A second release
liner 37 covers the rest of the distal side of the adhesive,
whereon the battery is not attached.
[0325] When applied to a surface, such as a skin surface of a
person, the first release liner 35 is removed. This exposed the
first adhesive layer, which may be adhered to the skin surface
thereby attaching the device 30 to the skin surface. The second
release liner is then removed exposing the second adhesive layer.
Not shown in the drawing, a housing containing a microelectronic
system is then attached to the adhesive layer while at the same
time an electrical contact on the housing is brought into
electrical connection which the battery 32.
[0326] Although such a housing as described above do not have any
surface contact such as the housing described with reference to
FIG. 19, the housing may still comprise sensor technology. Such
sensors may simply measure the ambient temperature or the device
may be applied under the nose and a sensor for measuring the
breathing rhythm through the nose may be applied on the device.
Alternatively the sensor may apply skin contacting transducers
outside the circumference of the device, while still being adhered
thereto.
[0327] FIG. 23 shows yet another embodiment 40 of a two-dimensional
device according to the invention and FIG. 24 shows a sectional
view of the third embodiment along line XXIV-XXIV in FIG. 23. Here
the power source element is formed as a thin film battery 41 being
an integrated part of a backing layer 42.
[0328] On the proximal side of the backing layer there is applied a
first adhesive layer 43 which is covered by a first release liner
44. The distal side of the backing layer is covered by a second
adhesive layer 45 which is covered by a second release liner 46.
The second adhesive layer is interrupted in an area 47 allowing
access to contacts 48a and 48b which provides electrical contact to
the thin film battery.
[0329] When used the device 40 described with reference to FIG. 23
is applied in the same way as the device 30 described with
reference to FIG. 22.
[0330] It should be understood that different types of adhesives
may be used on respectively the proximal side of the backing layer
and the distal side of the backing layer. While the proximal side
is attached to the skin surface and thus preferably should be skin
friendly, the adhesive on the distal side should preferably be of a
type which provides optimal attachment to a electronic circuit or a
housing containing such circuit while still allowing the device to
be separated there from after use.
[0331] Although the above embodiments describe releasable
attachable means in shape of adhesive attachment for connecting the
device to the electronic circuit other types of release attachable
means may be used. Such releasable attachable means can for example
be mechanical such as a snap lock arrangement between the battery
and the recess in the housing, where the recess is formed with
protruding ribs which couples with the battery. Alternatively
additional coupling means may be provided on the device for
coupling with complementary coupling means on the electronic
circuit or the housing containing the electronic circuit, and may
for example be in the shape of bayonet coupling, hooks, frictional
couplings or threaded couplings.
EXPERIMENTAL SECTION
Example 1
[0332] Three batches of adhesive were produced. The adhesives were
prepared by standard hot melt procedure in a Herman Linden z-blade
mixer (Machine type LK 110.5), by mixing the components of
elastomer (Kraton), one third of the plasticiser (DOA) and the
resin (Arkon) at 130 degree C. until a homogeneous mixture was
achieved (30-50 minutes). The rest of the plasticiser and the
hydrocolloid filler (CMC) was added and the mixture was blended for
20 minutes.
TABLE-US-00001 Recipe 1 Recipe 2 Recipe 3 Kraton 1161 18.0 19.0
15.0 (Shell) Arkon P90 32.0 36.0 (Arakawa DOA (Dioctyl adipate) 5.6
7.5 Vistanex.sup. .RTM. LM-MH 45.0 (Exxon) CMC: Blanose 44.4 37.5
400 9H4XF (Hercules)
Example 2
Moulded Bodies of the Adhesives of Example 1
[0333] Each of the adhesives according to claim 1 were applied on
to a 35 micrometer thick cover film of polyethylene and a
siliconised polyethylene liner was applied to the opposite side of
the adhesive patch and pressed to the desired shape according to
any of the illustrations 1-3 in a for the shape designed mould at
90 degree C. by altering the non-cavity holding mould to give the
shape of the recess. The centre of the adhesive device was 3.4 mm
and the thickness of the outer rim 0.4 mm.
Example 3
Moulded Silicone Pressure Sensitive Adhesive Body
[0334] Dow Corning 7-9800 A&B (mixing ration between A and B is
1:1 by weight) were used for production of a PDMS based adhesive
body. A mould having a triangular shape (each side of the
triangular mould having a distance of 300 mm, the center part
having a thickness of 0.5 mm and the edge having a thickness of 0.1
mm) was used. The components were thoroughly mixed and applied on a
50 .mu.m cover layer of silicone rubber lining in the female part
of a triangular mould and a male mould part was placed on top, said
part lined with a low density polyethylene release liner. The
adhesive was cured in an oven at 100 degree C. for 15 minutes.
After curing the adhesive was punched out of the mould and a dent
in the centre of the adhesive body device for embedment of an
electronic sensing system was punched out.
Example 4
Moulded Thermoplastic PSA Adhesive Body
[0335] The components of recipe 2 in example 1 were mixed in a
Herman Linden mixer and while still hot and soft, the resulting
dough-like material mass was removed from the mixer and placed on a
thermoplastic polyurethane cover film placed in the cavity of a
moulding form and a release liner is placed on top. The second part
of the mould was plane. The adhesive is compression moulded at
approximately 90 degree C. and 100 bar. The release liner was
removed and an encapsulated microelectronic sensing system was
placed at the centre of the adhesive body within the mould, the
release liner was reapplied and the moulding step was repeated.
Finally the resulting sensor pad was punched out.
Example 5
Moulded Thermoplastic PSA Adhesive Body with Integrated
RFID-Tag
[0336] A pressure sensitive adhesive according to recipe 2 in
example 1 were mixed in a Herman Linden mixer and while still hot
and soft a minor part of the material was removed from the mixer
and placed on a cover film towards the female part of a mould and a
release liner was placed on top and thereafter the male part of the
mould having a small protrusion over the area corresponding to the
microelectronic system of the product was applied. The whole
construction is compression moulded at approximately 90 degree C.
and 100 bar. Hereafter the release liner was removed and a RFID tag
encapsulated in polypropylene was placed in the recess of the
pressure sensitive adhesive and the mould was filled up with the
remaining adhesive. A release liner is attached again and the whole
construction was compression moulded again. The resultant pad was
punched out. The thickness of the outer rim was 0.2 mm, the central
thickness was 2.5 mm and the shape was circular with a diameter 40
mm.
Example 6
[0337] In this example the micro electronic system embedded into
the adhesive body consist of both the RFID tag and communication
and storage components. In order to protect the micro electronic
system the components are encapsulated in polyethylene. The
components are integrated in the PSA during a continuous process as
described in U.S. Pat. No. 6,726,791. The primary layer comprises
the cover film with pressure sensitive adhesive, the secondary
layer is the encapsulated micro electronic part; and the third
layer is of a mouldable layer pressure sensitive adhesive; the
whole construction is combined in the moulding cavities.
Example 7
Preparation of a Hydrogel Adhesive Composition
[0338] 3.5 grams of PVP K-90, 17.5 grams of PVP K-25, 3.5 grams of
Pemulen TR2 and 28 grams of PEG 400 were mixed as a premix.
Initially the premix of the plastizicing glycols, the PVP and the
cross-linked polyacrylic acid were added and mixed in a Brabender
mixer at 100 degrees C. for 10 minutes. Then 17.5 grams of the
amphiphilic polyurethane (Tecogel 2000) was slowly added in order
to ensure complete mixing of the components. After 20 minutes'
mixing a macroscopically homogenous mixture was obtained. The hot
adhesive from the mixing chamber was moulded into a circular
adhesive body (diameter 4 cm) with a dent for a later applied micro
electronic system. The thickness of the pad is 3 mm at the centre
and the thickness is gradually decreasing to 0.3 mm at the edge of
the pad. The adhesive device was compression moulded between a
sheet of silicone paper and a 30 mm PU cover film.
Example 8
A Microelectronic Sensing System for Invasive Measurement of
Oxygen
[0339] An adhesive according to example 1 recipe 2 was used
embedment of a micro electronic system consisting of an oxygen
electrode, a central processing unit, a transmitter and a battery.
The shape of the adhesive body is oval (70.times.30 mm) having a
centre thickness of 5 mm, an edge of 0.3 mm and an essential linear
increase in thickness from the edge to centre of the pad. The
adhesive body has a centrally placed through hole and a dent in the
skin-contacting part of the surface of the adhesive body for the
silicone covered micro electrical components.
[0340] The CPU, the battery and the transmitter are as described in
the examples 11. The oxygen electrode was oxygen electrode product
number 723 (from Diamond General, Development Corp. US).
[0341] The CPU, transmitter and battery were electrically connected
and thereafter covered with a thin layer of polymeric silicone,
only the electrical contact of the CPU to the electrode, remains
uncoated.
[0342] The tip of the electrode in the sensing device is surrounded
with a medical needle with outer diameter of 0.7 mm.
[0343] During use the electrode and the needle are positioned in a
way where the electrical contacts of the CPU are connected with
corresponding contacts of the electrode.
[0344] During application of the measuring device the partly
silicone covered micro electronic system was firstly applied onto
the adhesive body in the dent at the skin contacting side of the
device. The device is applied to the skin. The needle is then
positioned from the outside through the hole in the adhesive by
penetrating the skin in a second step and the electrode partly
enveloped in a plug is mounted through the hollow centre of the
needle as a third step creating electrical contact to uncoated
connections of micro electronic system. The plug part of the
electrode fits the smooth curvature of the cover film without
introducing recesses.
[0345] During use, the electrode may be rinsed and reapplied
according to needs for achieving correct signals.
Example 9
Microelectronic Hub Embedded in Adhesive Sensor Device According to
the Invention
[0346] An adhesive according to example 1 recipe 1 was moulded in a
first layer forming an oval shell (50.times.80 mm) having a smooth
surface to one side. This surface is declining in slope towards the
outer periphery and is covered with a 30 .mu.m thin film of
polyurethane i.e. placed between mould and adhesive. The opposite
side of the adhesive body was formed with a centrally soft shaped
indentation of approximately 2.times.10.times.15 mm for applying
the microelectronic system. A siliconised release liner of
polyethylene was placed on the surface with the indentation. In a
second step the release liner was removed, an antenna is placed at
the outer periphery of the adhesive body and the CPU and the
battery was placed in the central indentation. In a final step a
second layer of adhesive was applied to embed the antenna at the
area of the outer periphery but not the components in the central
indentation. A release liner is applied and the complete construct
which was die cut to the final size. The antenna is connected to
the central microelectronic parts through electrical contacting
elements making reuse of the central part possible. The antenna is
encapsulated in thin polyethylene terephthalate (PET)-plastic and
the central microelectronic parts are encapsulated in silicone
rubber.
Example 10
Microelectronic Hub
[0347] A construction with microelectronic hub in which the antenna
as well as the battery is completely integrated in the pressure
sensitive adhesive of previous example 1. This is done by letting
the adhesive of the final step in example 9 cover the antenna as
well the central microelectronic parts.
Example 11
[0348] An adhesive device having embedded a microelectronic system
for human temperature sensing and alarm with no remote
communication
[0349] An adhesive according to example 1 recipe 2 was used for
embedment of a micro electronic system consisting of an temperature
sensor, a central processing unit, a transmitter, battery and an
OLED (Organic Light emitting Diode). The shape of the adhesive body
is round (30 mm) having a centre thickness of 5 mm, a peripheral
edge of 0.2 mm and an essential linear increase in thickness from
the edge to centre of the pad. The adhesive body has a dent in the
skin-contacting part of the surface for the silicone covered micro
electrical components.
[0350] The CPU is a .mu.Controller ATMEGA 128L, an AVR 8 bit RISC
processor from ATMEL, Battery is an Panasonic Coin cell CR3202.
OLED flexible colour display is from OSD (One Stop Display) part
#OSCC 130-0. Temperature sensor is from Pasport Ps-2125
[0351] During use the temperature sensor continuously monitors
human skin temperature. At certain events determined by the
micro-Controller influenced by time of day, temperature gradient
compared to stored data, the system will give a visual alarm in
form text or lights of relevant information at the flexible
display.
[0352] The system is integrated into the adhesive and activated
when peeling off the release liner and will function until end of
battery.
Example 12
[0353] An adhesive device having embedded a microelectronic system
for human temperature sensing and alarm with no remote
communication is constructed according to example 11.
[0354] The construction of the adhesive device is identical to the
one of example 11 except that instead of the OLED flexible colour
display for signalling a temperature change an EL
(Electro-lumiscent Lamp) is used as the signalling part in the
surface of the device. The part is an EL Lamp Part #: 300210KIT
from Being Seen Technologies.
[0355] During use the temperature sensor continuously monitors
human skin temperature. At certain events determined by the
micro-Controller influenced by time of day, temperature gradient
compared to stored data, the system will give a visual alarm in the
form of a light.
Example 13
[0356] In one embodiment illustrated with reference to FIGS. 19-21
the adhesive material 19 is a pressure sensitive adhesive (PSA)
consisting of a hot-melt processable styrenic block copolymer with
hydrocolloids, the battery is a metal cased coin cell battery and
the housing is coated with a layer of PolyDiMethylSiloxane.
[0357] In Example 13 below, the peel forces between the PSA and the
surface, the battery and the housing were determined:
[0358] The PSA is a hot-melt processable Styrenic block copolymer
with hydrocolloids, which is thermo formed into the desired shape.
The PSA designated A, has the following composition: 25% Kraton
D1107 (Kraton Polymers), 35% Arkon P90 (a hydrogenated
polycyclopentadiene from Arkawa Ltd.) 8% DiOctylAdipate and 32%
sodium carboxymethylcellulose.
[0359] In order to illustrate the peel force between the different
parts the peel force has been determined via use of FINAT; FTM2, 25
mm test sample width, 90 degrees peel angle, test speed of 300
mm/min and a resting time of 30 minutes.
[0360] With regard to peel force from skin the following test
method was utilized:
[0361] Strips of adhesive 25 mm wide were cut from slabs of PSA
composition A. A strip of adhesive tape (TESA 4124) was attached in
order to prevent stretching of the samples. The samples were taped
to a clamp. The skin of the volunteer was prepared by washing the
underside of the forearm with diluted soap and allowing to dry at
least 2 hours before the PSA was attached. The adhesive side of the
sample was placed on the prepared skin. The resting time for the
adhesive was 30 minutes. The clamp was attached to the hook of the
testing device, an Instron Tensile tester Model 5564. The forearm
was placed on a movable support of the testing device, taking care
to keep the end of the sample directly under the clamp in order to
keep a 90-degree peel angle. The forearm was kept still while the
tensile strength tester was activated to pull the adhesive up at a
rate of 300 mm/min. The peel value of the steady state part of the
resulting graph was recorded and it was confirmed that no residue
was left on the skin of the forearm.
[0362] The battery was a metal cased Manganese Dioxide Lithium coin
cell battery CR2330, from Panasonic, and the microelectronic
housing was coated with a layer of PolyDiMethylSiloxane (PDMS);
MED-1137 from NuSil Technology.
[0363] The peel forces have been determined between the adhesive
and the following parts with following results and with three
repetitions of the test, where s indicates the standard
deviation.
TABLE-US-00002 Peel force between A and PDMS 0.1 N/25 mm coated
housing Peel force between A and steel 22.5 N/25 mm (s = 2.3) Peel
force between A and human skin 2.5 N/25 mm (s = 0.25)
Furthermore, different types of materials may be used for different
parts of the device and the microelectronic circuit and/or the
housing whereby different peel forces may be provided. Thus it
would be possible to achieve peel forces between the PSA and the
skin in the general range of 1-5 N/25 mm, peel forces between the
PSA and the housing generally below 1 N/25 mm and the peel forces
between the PSA and the metal casing of the battery generally above
20 N/25 mm.
[0364] It can thus be understood, that when the sensor assembly 1
has been applied to the skin of a user it may easily be peeled off
after use, by pulling the adhesive element with a force above the
peel force between the PSA and the skin. The adhesive element 5 may
then easily be separated from the housing element 3 containing the
microelectronic circuit 4. As the peel force between the adhesive
element and the battery 6 is much higher than between the adhesive
element and the housing, the battery is practically inseparable
from the adhesive element, and thus the battery will be attached to
the adhesive when the adhesive is separated from the housing.
[0365] The invention being thus described, it will be apparent that
the same may be varied in many ways. Such variations are not to be
regarded as a departure form the spirit and scope of the invention,
and all such modifications as would be recognized by one skilled in
the art are intended to be included within the scope of the
following claims.
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