Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE
. MOISTURE DETECTING DEVICES SUCH AS FOR DIAPERS
AND DIAPERS HAVING SUCH DEVICES
FIELD OF THE INVENTION
This invention relates to devices for
monitoring wetness, particularly in diapers, and to
diapers containing such devices.
BACKGROUND OF THE INVENTION
Various methods and means have been developed
for monitoring moisture or wetness in diapers. The
purpose of such devices is to set off an alarm when a
diaper becomes wet. This permits a mother to tend to a
newborn infant or toddler. However such devices have
disadvantages in that they may require conductors to
pass mechanically through the diaper's plastic outer
sheath, may subject the skin of the wearer to direct
voltages from a voltage source, may be sensitive only
in a limited area, may accidentally respond to the
wearer sitting on a wet or metal bench or park slide,
or have other drawbacks.
SUMMARY OF THE INVENTION
According to an embodiment of the invention,
a pair of spaced electrodes within the area subject to
wetness couple non-conductively with a sensor protected
from wetness, and an alarm sounds in response to
moisture decreasing the resistance between the
electrodes. For example the electrodes project into
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the absorbent material of a diaper and extend along the
inside of the diaper sheath opposite a pouch on the
outside of the sheath. The pouch contains a sensor
capacitively coupled to the electrodes.
The various features of novelty which
characterize the invention are pointed out in the
claims forming a part of this specification. Objects
and advantages of the invention will become evident
from the following detailed descriptions of embodiments
of the invention when read in light of the following
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an exploded view of a diaper
embodying the invention.
Fig. 2 is a perspective view of Fig. 1.
Fig. 3 is circuit diagram of a sensor used in
Figs. 1 and 2.
Figs. 4 and 5 illustrate an embodiment of a
pouch in Figs. 1 and 2.
Fig. 6 is a plan view of the rear of an
embodiment of a diaper with a pouch on the outside and
containing a sensor.
Fig. 7 is an frontal elevation of the rear of
the diaper, when opened, in Fig. 6.
Fig. 8 is a plan view of the rear of another
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embodiment of a diaper with a pouch on the outside and
containing a sensor.
Fig. 9 is an frontal elevation of the rear of
the diaper, when opened, in Fig. 8.
Fig. 10 is a perspective view of a sensor
embodying the invention.
Fig. 11 is a block diagram of another
embodiment of the invention.
Fig. 12 is a flow chart which illustrates the
steps performed by the processor in Fig. 11.
Fig. 13 is a continuation of the flow chart
in Fig. 12.
Fig. 14 is a block diagram of a chip that,
according to an embodiment of the invention, serves in
place of a circuit in Fig. 3 or the processor of Fig.
il.
Figs. 15A, 158, and 15C illustrate the
waveforms induced on the sensing circuit by the chip
after current limiting by an external resistor.
Fig. 16 illustrates the pins of the chip in
Fig. 14.
Fig. 17 illustrates the operation with a
piezoelectric element as the only output.
Fig. 18 illustrates the operation with only
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an LED output.
Fig. 29 illustrates the operation with
piezoelectric and LED outputs.
Fig. 20 illustrates the operation with an LED
and external DC-powered output circuit.
Fig. 20A illustrates operation with an
external DC-powered output circuit only.
Figs. 21A and 21B are exploded perspective
views of a diaper conveying two embodiments of the
invention.
Figs. 22A, 22B, 22C, and 22D are plan views
of surfaces that bear electrode arrangements
corresponding to several embodiments of the invention.
Figs. 23A and 23B are plan views of surfaces
that bear electrode arrangements corresponding to other
embodiments of the invention.
Fig. 24 is an elevation of an electrode
arrangement corresponding to an embodiment of the
invention.
Fig. 25 is an elevation of an electrode
arrangement corresponding to another embodiment of the
invention.
Fig. 26 is an elevation of an electrode
arrangement corresponding to another embodiment of the
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invention.
Fig. 27 is a perspective view of an electrode
arrangement corresponding to another embodiment of the
invention.
5 Fig. 28 is a perspective view of an electrode
arrangement corresponding to another embodiment of the
invention.
Fig. 29 is a perspective view of a pocket
with aspects embodying the invention.
Fig. 30 is a perspective view of a pocket
with a further aspect embodying the invention.
Fig. 31 is a perspective view illustrating
the folding of a sensor element to shorten its
effective length.
Fig. 32 is a perspective view illustrating an
apparatus for the removal of a coating from an area of
coated film.
Fig. 33 is a perspective view illustrating an
apparatus for the placement of the sensing electrodes
onto a diaper backing sheet web.
Fig. 34 is a perspective view illustrating an
apparatus for the removal of non-conductive fibers from
a wire-wrapped yarn.
Fig. 35 is a sectional view illustrating an
example of a module in a pocket on the back of a
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diaper.
Fig. 36 is a plan view of the frontal area of
a diaper having a cloth-like backing sheet and a
treated rectangular portion.
Fig. 37 is a sectional view through an area
of cloth-like backing sheet containing a treated
portion.
Fig. 38 depicts an ultrasonic apparatus for
processing of the treated portion of Figs. 16 and 17.
Fig. 39 is a perspective view of a diaper
produced by the process of the invention.
Fig. 40 is a schematic representation of a
machine for constructing diapers.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the exploded view of Fig. 1 and the
partially-exploded perspective of Fig. 2, a disposable
diaper 100 embodying the invention includes an inner
sheet 104 of a water-permeable film which overlies a
wetness absorber layer 107 of powerfully liquid-
absorbent padding or other powerfully absorbent
material. In one embodiment the layer 107 may include
a gel-forming absorbent resin. An outer water-
impermeable electrically-insulating plastic sheath 110
supports two conductive spaced-apart electrodes 114, in
the form of metallic or other electrically-conductive
strips, that extend along the center of the sheath 110
and in electrical contact with the absorber layer 107.
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According to an embodiment of the invention, the
electrodes 114 pass longitudinally through the layer
107. According to another embodiment, the electrodes
114 are in the farm of conductive threads or wires.
The sheet 104 is common to most disposable
diapers and is often referred to as cover stock. It is
composed of thick porous, relatively hydrophobic,
bonded fibers which tend to pass liquid in one
direction from the wearer to the absorber layer 107.
The urine is held away from the skin by the competition
between the highly absorbent layer 107 and the not-so-
absorbent sheet 104. In this way the relatively
hydrophobic fibers space the wet mass of the layer 107
from the skin of the wearer. This keeps the skin dry
even when the wearer has wet the diaper. The sheet 104
may be omitted in training diapers that intend to make
the wearer uncomfortable when the diaper is wet. The
diaper is worn in the usual fashion.
The electrodes 114 terminate in widened pairs
of adjacent fixedly spaced electrically-conductive pads
117 on each end. The pairs of pads 117 at each end are
printed on the sheath 110 or are bonded to the sheath
110 so they maintain a fixed position on the sheath 110
and so they are in intimate contact with the sheath.
According to another embodiment, the pads 117 are
otherwise deposited or applied, such as by selective
metallization, or carbonization using a laser. Bonded
to the outer face of the sheath 110, directly apposite
the pads 117 at each end of the sheath, are pouches
120. Each pouch 120 is adapted to receive a removable
sensor 124 having thin electrically-conductive
rectangular planar members or surfaces 127. Although
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twa pouches 120 exist, only one pouch receives a sensor
124. When two pouches exist, the selection of the
pouch which receives the sensor 124 depends upon the
preferences, e.g. based on the comfort, of the user.
The position of each pouch 120 is such as to
place the pair of planar members 127 on the sheath 110,
directly behind a pair of the pads 117 without
overlapping one member 127 with two of the opposing
adjacent pads 117 or vice versa. One of the pairs of
pads or members is larger than the other to permit
tolerance in placement.
According to an embodiment, each pouch 120 is
composed of or contains, in some portion, resilient
material (not shown) to press the members 127 into
position against the sheath 110 when the diaper is
worn. The members 127 do not electrically contact the
pads 117, rather the sheath 110 separates the members
from the pads. When a sensor 124 sits in the pouch
120, the pair of members 127 of the sensor 124, and the
opposing pair of pads 117 form two adjacent capacitors.
According to an embodiment, the sides of the
sensor 124 are tapered to facilitate insertion in the
collapsed pouch. The faces of the sensor 124 may also
be tapered.
As shown in Fig. 2, suitable fastening strips
130 secure the diaper in operable condition, and the
sensor 124 is placed in the pouch 120 at the rear or
front of the diaper. When a user wears and wets the
diaper, the liquid passes through the sheet 104 into
the absorber layer 107 and to the sheath 110. The
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liquid then electrolytically short-circuits the
electrodes 114. Hence the electrodes 114 operate as a
conductive switch which is open, i.e. non-conductive,
in a dry diaper and closed, i.e. conductive, in a wet
diaper.
According to another embodiment of the
invention, the diaper contains only one pouch 120. The
diaper may further comprise other accessories as may be
necessary or desired, such as elastic electrodes for
close fit to the wearer, tapes, tabs, snaps or the like
for fastening the diaper in place upon the wearer, for
example.
The sensor 124 contains an oscillating
voltage or pulse source, preferably one having a low
duty cycle, which capacitively couples to the members
127 to the pads 117 using the sheath 110 as the
dielectric medium, and an alarm device which responds
to the source. The spaced electrodes 114 form a switch
that remains open (non-conductive) when the diaper is
dry. The sensor 124 is set so varying current from the
source cannot pass through the open switch formed by
the electrodes 114. When the diaper is wet, the
electrolytic action of the urine in the diaper contacts
the electrodes 114 and closes the switch, i.e. makes it
conductive across the gap between the electrodes 114.
The sensor 124 is set so varying voltage of the source
then passes a current from the sensor 124 through the
capacitor formed by one member 127 and the opposing pad
117, through one electrode 114 through the
electrolytically conductive gap between electrodes to
the other electrode 114, through the capacitor formed
by the second of the pair of pads 117 and the second of
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the pair of members 127, back to the sensor. The
resulting current triggers an alarm which, according to
one embodiment, energizes a piezoelectric sounder and
plays a tune or makes some other sound such as a beep.
5 According to another embodiment, the alarm
takes the form of a blinking or turned on light, such
as an LED. According to another embodiment, the alarm
is transmitted by radio waves, infra-red radiation, or
other means to a remote position where an attendant can
10 monitor a number of children or other wearers.
The alarm, in the form of a sound or light,
informs the wearer, who may be an infant being trained,
or the infant's parent, that the diaper is becoming
wet. This allows prompt action. A sound or light
alarm may for example make the infant in training
associate its urges with its training needs. The sound
or light can also serve to notify an infant's parent
that the child's diaper needs changing. A sound or
light alarm can inform a toddler's attendant of these
needs. A sound alarm can be an aid in enuresis
training. A light alarm can also warn an elderly
incontinent or handicapped person without sensation in
the peritoneal area of an incident, or inform a
caregiver of the need for changing.
The sensor 124 sets an alarm threshold
sufficiently high to prevent a false alarm when a
wearer sits on a metal bench or on a wet surface. The
capacitive impedance between the pads 117 and members
127 is far less than that between the electrodes 114,
even when the electrodes 114 are in the vicinity of
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metal or a wet surface. Thus the electrodes 114
present a high impedance unless shorted electro-
lytically by urine in the diaper. The sensor threshold
is sufficiently high to avoid responding to the
capacitive coupling between the dry electrodes 114, and
yet low enough to respond to the electrolytic
conduction between the electrodes 114.
Sensing electrodes 114 are made to have such
a small surface area that the amount of capacitive
coupling between sensing electrodes 114 and any items
placed opposite them in contact with the outer surface
of backing sheet 110 will be so small that the amount
of current shunted to such external items will not be
detectable by detector module 124. As a consequence,
the alarm will not be activated as the result of
conditions external to the diaper 100, but only due to
electrolytic conduction between the sensing electrodes
114. An example of an external item that might be
placed against the outside of a diaper is a metal chair
that a wearer sits on.
Details of electrical portions of one
embodiment of sensor 124 appear in Fig. 3 which
includes a low duty-cycle pulser 300. Tn the pulser
300, an oscillator 304 and divider counter 307, forming
part of an integrated circuit or chip, provide the time
base for all events in the wetness detection process.
In one embodiment, the counter 307 yields a low
frequency pulse rate such as 30 Hz to a rising-edge
sensitive clock input of a D-type flip-flop 310. A
higher frequency pulse, some derivative of the same
clock, e.g. 60 kHz to result in a 2:2000 duty cycle,
furnishes a reset to the flip-flop 310 a brief period
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later. As a consequence, the flip-flop 310, which has
its data input connected to a positive supply 314,
clocks in a logic high which is reset 15 microseconds
later by the higher frequency clock. The inverting
output Q' of the flip-flop 310 is used and a
corresponding 15 microsecond logical low pulse is
subsequently generated. This low pulse appears at an
inverting amplifier 317 which drives an output pin on
the chip, and also appears at a rising-edge sensitive
clock input of second flip-flop 320. The buffered
output pulse from the inverter 317 passes to an
external resistor 324.
The external resistor 324 performs a charge
current limiting function in the external R/C circuit
formed with the diaper's capacitor-switch network 327.
The latter includes a first capacitor 330 formed by one
of the members 127 and one of the pads 117 facing each
other across the sheath 110, the resistance 334 of the
switch formed by the electrodes 114 and the gap between
them, and a second capacitor 337 formed by the other of
the members 127 and the other of the pads 117 facing
each other across the sheath 110.
The voltage at the resistor 324 and across
the capacitor switch network 327 also appears at a
Schmitt input buffer 340 which produces an output at
the D input of the flip-flop 320. The flip-flop 320 is
set at power-up to avoid a brief alarm. An output Q'
of the flip-flop 320 drives an alarm 344. In the
example shown in Fig. 3, the alarm 344 includes a beep-
producing piezoelectric crystal PZ, an LED, a radio
transmitter RT, an infra-red transmitter IR, a music
generating circuit MG, and a tactilely-sensible
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vibrator VB for enuresis training, any of which may be
energized selectively, either alone or all together.
The piezoelectric crystal PZ may also produce
ultrasonic chirps to communicate the alarm to a remote
or bedside receiver. According to other embodiments of
the invention, the sensor 124 includes any one or more
of the crystal, LED, radio transmitter, infra-red
transmitter, music generating circuit, or a tactilely-
sensible vibrator without the others. The others may
be omitted. Other means of alarm may be used. In one
embodiment only the piezoelectric PZ and the LED is
used.
In each charge cycle a 15 microsecond
current-limited pulse feeds into the capacitor-switch
network 327. Assuming the network 327 is initially
discharged, it begins to acquire a charge, the terminal
voltage of which is a function of the charging source
voltage, current-limiting resistor 324, the pulse
length, and the capacitance of the series-connected
capacitors in the sensor network 327. When the diaper
is dry the open circuit at the switch 324 between the
electrodes 114 allows the charge across the circuit 327
to rise rapidly toward its peak and beyond the
threshold of the Schmitt trigger 340. This places a
low at the output Q~ of the flip-flop 320. This holds
the alarm 320 off. The voltage rises rapidly because,
in the proximity of the dry layer 107, the total
capacitance of circuit 327 is extremely low, much lower
than the series capacitance of the capacitors 330 and
337.
When urine electrolytically shorts the
electrodes 114, the total capacitance of network 327
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rises substantially to approximately the series
combination of the value of the far higher capacitance
of coupling capacitances 330 or 337. The Schmitt
network 327 then appears as a capacitive load equal to
approximately the value of the series combination of
the fixed coupling capacitances 330 and 337. The
voltage across the network 327 then fails to rise above
the positive-going threshold of the Schmitt trigger
340. At the termination of the sensing pulse from
flip-flop 310 and inverter 317, flip-flop 320 is
clocked by the rising Q' output of flip-flop 310 and
stores the logic low level output of Schmitt trigger
340 as a logic high level on its Q' output. This high
level on the Q' output of flip-flop 310 activates the
alarm 344. At the next pulse, when the flip-flop 310
resets the flip-flop 320, the output at Q' of the flip-
flop 320 goes high and triggers the alarm 344.
More specifically, the resistor 324 has a
value such that the network 327 charges to at least the
threshold (typically 1.6 volts) of a Schmitt input
buffer 340, when the diaper is dry. Thus, at the time
of charge termination, and the exact moment when the
synchronous rising-edge clock is fed to the second
flip-flop 320, the instantaneous level of the output of
the Schmitt input buffer 340, being a function of its
presently imposed input voltage, is clocked into the
sampling flip-flop 320. The resulting state of the
outputs of flip-flop 320 indicate the wet or dry state
of the diaper in that previous instant and the whole
cycle recurs at the previously mentioned 30 Hz rate.
When the diaper is dry, the flip-flop 320
produces a 0 at the Q' output. When the diaper is
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wet, the charge does not reach the level needed to
cause the Schmitt input buffer 340 to apply a 1 to the
D input of the flip-flop 320. This produces a 1 at the
Q~ output of the flip-flop 320 and activates the alarm
5 344.
Beside the usual noise-reducing function
typical of Schmitt input circuits, this Schmitt input
buffer 340 provides an additional effect. As the
network charging pulse voltage varies in response the
10 power supply, so too varies the threshold voltage of
the Schmitt input buffer 340. This is because the
Schmitt threshold points are set by a voltage divider
as a fixed, moderate fraction directly from the supply
voltage. The effect is the reduction of supply
15 voltage-induced variations in the sensing threshold as
the battery voltage supply weakens, as would tend to be
the case when batteries are used as the power source.
The low pulse rate at the resistor 324 serves
at least two purposes. First, a relatively long zero-
voltage cycle helps assure that the voltage at the
network 327 returns to zero between pulses under all
conditions. Each cycle therefore tends to be isolated
from the previous one. The low duty cycle assures the
bias of the external capacitive network 327, thereby
eliminating the need for resistive bias components
were, for instance, a comparator used and were the
applied waveform a 50% duty cycle square wave. Second,
the average current required by the test circuit is
reduced by making the tests less frequent than they
might otherwise be, since the majority of test current
is drawn during the pulse. Since the required response
is in the order of one or more seconds, the average
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current consumption could theoretically be reduced to a
minimum by reducing the duty cycle to the extent that
the interval between pulses is made to be on the order
of the required response time.
According to an embodiment, for a duty cycle
of 1:2000 for the applied pulse, the values of the
resistor 324 and the threshold of the Schmitt trigger
can be selected so the average power applied to the
series resistor, coupling capacitors, and electrodes
approximates 3 nanowatts of power.
Figs. 4 and 5 illustrate an embodiment of a
pouch. Here, an adhesive holds an outer curved flange
407 of an elastic pouch 410 against the outside of the
outer water-impermeable electrically-insulating sheath
110. According to another embodiment of the invention,
a thermal bond holds the flange 407 to the sheath 110.
When the sensor 124 is inserted into the pouch 410, the
pouch shapes itself securely about the sensor.
Fig. 6 is a plan view of the rear of an
embodiment of a diaper with a pouch 410 on the outside
of the sheath 110 and containing a sensor 124. Fig. 7
is an frontal elevation of the rear of the diaper, when
opened, in Fig. 6. Here, the thicknesses are
exaggerated for clarity. The sensor 124 in the pouch
410 carries the members 127 and presses them against
the outside of the sheath 110 opposite the pads 117
printed on the inside of the sheath. A substrate 600
supports the pads 117. A layer 604 common to existing
disposable diapers covers the pads 117 and the sheath
110, and provides a mounting surface for an absorber
layer 607 corresponding to the layer 107. The latter
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is also common to most disposable diapers. Covering
the absorber layer 607 is a relatively hydrophobic
inner sheet 610, also common to disposable diapers, and
corresponding to the sheet 104. The relatively
hydrophobic fibers space the wet mass of the layer 607
from the skin of the wearer and do not conduct moisture
back to the skin. This keeps the skin dry even when
the wearer has wet the diaper. The urine is held away
from the skin by the competition between the highly
absorbent layer 607 and the not-so-absorbent sheet 610.
Fig. 8 is a plan view of the rear of another
diaper similar to the diaper in Figs. 6 and 7, but
using bare wires or conductive threads 614 as the
electrodes 114. Fig. 9 is an frontal elevation of the
i5 rear of the diaper, when opened, in Fig. 8. Here also,
the thicknesses are exaggerated for clarity. The bare
wires or conductive threads electrically connect to the
pads 117 as they are squeezed between the pads and the
sheath 110. According to another embodiment, the wires
or conductive threads 614 pass through the absorber
layer 607.
In the embodiments of Figs 6 to 9, as in
other embodiments, when the diaper is dry the sensor
124 produces no alarm. The spaced electrodes 114 form
the electrically conductive switch that remains open
when the diaper is dry. Varying current from the
source can then not pass through the open switch formed
by the electrodes 114. When the diaper is wet, the
electrolytic action of the urine in the diaper contacts
the electrodes 114 and closes the switch, i.e. across
the gap between the electrodes 114. The varying
voltage of the source then passes a current from the
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sensor 124 through the capacitor formed by one member
127 and the opposing pad 117, through one electrode 114
through the electrolytically conductive gap between
electrodes to the other electrode 114, through the
capacitor formed by the second of the pair of pads 117
and the second of the pair of members 127, back to the
sensor. The resulting current energizes the alarm
which, according to one embodiment, energizes a
piezoelectric sounder and plays a tune or makes some
other sound such as a beep.
According to another embodiment of the
invention, the sheets 104 and 610 are omitted to give
the wearer a sensation of wetness and reinforce the
alarm.
According to another embodiment, the wires or
threads 614 are buried in the absorber layer 607 and
fixedly contact a pair of thin plates within the layer
607. The sensor 124 with the members 127 is then
insulated and also buried in the absorber layer.
According to another embodiment, the arrangement is the
same as in Figs. 1 to 9, but rather than using pouches,
the sensor 124 with members 127 is fastened to the
sheath 110 by mechanical clips, snaps, or quarter turn
locking units on the outside of the diaper.
Fig. 10 is perspective view of an embodiment
of a sensor 1000 corresponding to the sensor 124. This
includes a housing 1004, an extractor tab 1007,
slightly-downwardly tapered sides 1010 and beveled
edges 1014. The tapered sides permit alignment on
insertion into a pouch. An optional spring loaded
switch 1017 is turned on when the sensor 1000 is place
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in a pouch. The dimensions of the sensor 1000 are such
as to fit securely in a pouch. The housing has a rear
face 1020 which is curved to furnish a contact force
against the sheath 110 and the pouch when place in a
pouch.
According to other embodiments, the pads 117
use very thin layers of metals selected for
reflectivity as well as oxidation and corrosion
resistance. Sputtered or vaporized aluminum covered
with nickel avoids oxidation and presents an
aesthetically pleasing white appearance outside the
diaper.
According to other embodiments, the sensor
arrangement is used to inflate a life vest when the
vest touches water, in bird feeder water supplies to
indicate dry conditions, security doorknobs which
respond to skin moisture, liquid level sensors, plant
soil moisture indicators, etc.
The invention permits a mother to tend to a
newborn infant or toddler, to alert a child during
toilet training that it is wetting, to help in enuresis
training, and to forewarn the incontinent elderly of a
problem before it arises. The invention avoids
connecting the source mechanically to the conductors in
the diaper from the outside. It also frees the skin of
the person wearing the arrangement from direct contact
with the voltages that the source applies to the
electrodes. Moreover, it avoids a false alarm when the
wearer sits on a wet or metal bench, leans on a wet or
metal wall, or descends on a metal or wet park slide.
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According to other embodiments of the
invention, the non-conductive coupling from the sensor
to the electrodes is optical rather than capacitive.
This involves using an LED and light detector
5 combination on opposite sides of the sheath 110.
According to another embodiment, the non-conductive
coupling from the sensor to the electrodes is magnetic.
This involves applying an electromagnetic field from
the sensor in the pouch and then having the field
10 sensed inside the diaper. According to another
embodiment, the non-conductive coupling from the sensor
to the electrodes is inductive from the sensor to the
electrodes.
According to another embodiment of the
15 invention, the speed of the response of the switch
formed by the electrodes 114 is varied by changing the
relative hydrophobic and hydrophilic correlations of
the layers 104 and 107.
The sizes of the members 127 and the pads 117
20 are sufficiently large, and the face to face spacing
between each pad 117 and the opposing member 127 across
the dielectric sheath 110 is sufficiently small, so
that the capacitances 330 and 337 formed thereby are
substantially greater than the very small, almost
unmeasurable, stray capacitance between the side-by-
side electrodes 114. The Schmitt trigger 340 is set at
a low enough value, and the capacitances 330 and 337
are sufficiently high, so that even when a child sits
on a wet or metal surface, the stray capacitance across
the switch 334 formed by the electrodes 114 does not
add enough capacitance to the series circuit 327 to
drop the input to the Schmitt trigger below its
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positive-going threshold. Hence, the flip-flop 320
will not set off a false alarm in response to the
wearer sitting on a wet or metal surface. The
dimensions are set to set off the alarm only in
response to conduction across the switch 334 formed by
the electrodes 114.
Fig. 11 is a block diagram of another
embodiment of the invention wherein a processor 1400
performs the functions of the circuit 300 and members
340 and 320 in Fig. 3. The structure of the system is
otherwise the same as shown in Fig. 3.
Fig. 12 illustrates the steps performed by
the processor 1400. Here, in step 1504, the processor
1400 powers up in response to the detector module 20
being turned on, for example, when it is placed in the
pouch of a diaper for the first time (i.e., by a
latching switch activated by one of levers 37A or 37B).
In step 1507, the system is reset after a
predetermined elapse of time. In step 1510, the
processor 1400 detects the hard wire condition to
determine which of the devices in alarm 344 are
connected for the purpose of creating the alarm. In
step 1514, the processor 1400 determines whether the
system is set for an alarm to occur immediately upon
sensing or whether a short delay should occur. In step
1514, the processor 1400 may also determine whether the
number of operations (alarm conditions) should be
counted, said counting to occur only after the
aforementioned short delay has expired.
In step 1517, the processor 1400 generates
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pulses on a continuous basis. As shown in figure 3,
these test pulses are applied to network 327 via
resistor 324. In "threshold reached?" decision step
1520, the processor 1400 determines whether the voltage
has reached a predetermined value, typically a moderate
fraction of the supply voltage, such as 40~.
If the result is YES, this means that a
conductive condition is not present at switch 334, and
the sequence of steps that could lead to activation of
the alarm is not begun. Instead, upon each such
determination, in the "final alarm counted" decision
step 1528, the processor checks whether the alarm
counter had flagged a final alarm during the previous
alarm event. If the alarm counter was not enabled in
configuration step 1514, then the result of this
decision will always be NO. If it is YES, step 1530
disables the outputs so that the unit will no longer
function. If NO, step 1532 initializes the delay timer
(it does not matter whether or not the delay timer is
actually flagged for use in qualifying alarm
conditions). Next, the "alarm in progress?" decision
step 1535 checks whether there is an alarm condition
present. If YES, step 1538 deactivates whatever
signals had been active, and the processor returns to
the "threshold reached?" decision step 520. If NO,
step 1538 is skipped, and the processor returns
directly to the "threshold reached?" decision step
1520.
If the result of the "threshold reached?"
decision step 1520 is NO, this means that a conductive
condition is present at switch 334, and the sequence of
steps that could lead to activation of the alarm is
begun. Upon each such determination, the "delay
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feature engaged?" decision step 1522 checks whether the
delay feature has been flagged as being engaged. If
YES, the "delay underway?" decision step 1524 checks
whether a delay is currently underway. If YES, the
unit will pulse the LED output pin at 8 Hz and return
to the decision step 1524, where it will continue to
check for the end of the delay period, rather than
proceed with an alarm condition. If an LED is
connected, a user of the product can see that a
qualified alarm may be imminent, which helps prevent
inadvertent activation of the alarm counter due to some
form of mis-handling of the unit. Qnce the delay
period is over, the result of the "delay underway?"
decision step 1524 will become N0, as long as the
result of the "threshold reached?" decision step 1520
persists in the NO condition, and this is what results
in a positive alarm condition.
Fig. 13 is a continuation of the flow chart
in Fig. 12, showing the steps that may occur upon the
occurrence of a positive alarm condition. First, in
step 1604, the alarm counter is incremented by a count
of one, if it was enabled in the configuration step
1514. Next, in step 1521, the alarm condition is
latched (i.e., by use of a persistent flag). Then, in
the "last alarm?" decision step 1607, the processor
checks whether this is the last alarm. If the alarm
counter was not enabled, this decision will always be
NO. If it is YES, the processor pulses the LED pin at
8 Hz, contrary to the usual 2 Hz rate, to indicate that
the unit will not function after this alarm. Next, the
"piezo?" decision step 1618 checks whether
configuration step 1510 flagged that a piezo is
connected. If YES, then the processor will feed the
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non-LED output pin with a signal that will cause an
audio piezo transducer to produce a steady monotone.
This tone is different from the usual warbling tone to
indicate that the unit will not function after this
alarm. If NO, then the processor will supply DC power
the non-LED output pin for the purpose of driving any
of a number of possible output devices.
If the result of the °last alarm?" decision
step 1607 is N0, the processor pulses the LED pin at 2
Hz. that the unit will not function after this alarm.
Next, the "piezo?" decision step 1619 checks whether
configuration step 1510 flagged that a piezo is
connected. If YES, then the processor will feed the
non-LED output pin with a signal that will cause an
audio piezo transducer to produce a warbling tone. If
NO, then the processor will supply DC power the non-LED
output pin for the purpose of driving any of a number
of possible output devices.
It will be evident that certain details of
the internal logic of processor 1400 are different from
circuit 300, most obviously the latching of the alarm
condition. This was done to facilitate implementation
in software/firmware. The essential functions,
however, remain common to the two.
With reference to the use of the alarm
counter in any implementation, in the usual commercial
context, it is expected that a detector module 20 has
sufficient battery power to operate with one pack of
diapers. Any attempt to use the device with a second
pack of diapers would likely result in a failure of
operation at some time during use with one of those
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diapers due to the dead or dying battery. Accordingly,
the processor 1400 and the circuit 1700 count the
number of operations and continue in operation only for
the number of diapers in a single package. The number
5 of possible alarms may be increased slightly over the
package count to allow for the possibility of
inadvertent alarms caused by mis-handling (such as re-
insertion into an already wet diaper). This assures
continued operation without failure in the middle of a
10 pack.
Fig. 14 is a block diagram of a chip 1700
that, according to an embodiment of the invention,
serves in place of the circuit 300, Schmitt trigger
340, and flip-flop 320 of Fig. 3, or in place of the
15 circuit 300 of Fig. 3 or in place of the processor 1400
of Fig. 11. The chip 1700 senses the state of the
switch 334 in the network 327. Specifically it senses
whether a conductive condition is present at switch 334
in the network 327, indicating the presence of a
20 conductive electrolyte across the sensing electrodes,
as evidenced by the effect of the load presented by the
series combination of substantially fixed-value
capacitors 330 and 337 on the voltage at the connection
to network 327 as of the end of the sensing pulse. The
25 basic concept used is to generate short, current-
limited, periodic, electrical test pulses to network
327. If network 327 is connected by the closure of
switch 334, then network 327 serves to load down the
test pulse, but if switch 334 is open, the pulse will
be for practical purposes unaffected. The circuit
checks the voltage at the connection to network 327 at
the end of each pulse, and can detect the state of
switch 334 by comparing this voltage to a predetermined
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threshold.
Fig. 15A illustrates the test pulse applied
to the network 327, and Figs. 15B and 15C illustrate
the waveforms induced on the network 327 by the test
pulses after current limiting by an external resistor
using typical values. There is a schematic insert
indicating the nodes on an equivalent circuit for which
the voltages are plotted. V(1), the test pulse, is
shown in Fig. 15A. V(2), the voltage across network
327 for the case of a dry diaper, is shown in Fig. 158.
V(2) is also shown in Fig. 15C, this time for the case
of a wet diaper. The sensing threshold is shown in
Figs. 15B and 15C as a level at approximately 0.8V.
The distortion seen in the waveform in Fig. 15B for the
case of a dry diaper is caused by the deliberate
inclusion of relatively large strays in the simulation
model to demonstrate immunity to such strays.
Fig. 16 illustrates the pins of the chip
1700. It shows the external circuit connections to the
CT chip. The connection (pin) characters shown in Fig.
16 correspond to those in Fig. i4.
The chip 1700 structure offers several
different module configurations to satisfy the needs of
different users. The primary module implementations
appear in Figs. 17, 18, 19, 20, and 20A.
Fig. 17 illustrates the operation with a
piezoelectric element as the only output. Here, the
piezoelectric element PE is connected between the "B"
and "C" pins and the "A" pin is left unconnected.
The sensing circuitry is the same in all of the
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configuration illustrations. The supply voltage applied
across the "+" and "-" pins is shown as a battery B.
The "D" pin input is shown to be optionally connected
to either the "+" pin or to the "-" pin. This provides
two versions for each configuration; the delay and
count operation may or may not be enabled in each of
the five configurations of Figs. 17 to 20 and 20A.
Fig. 18 illustrates the operation with an LED
as the only output. The LED is driven from the "B"
pin. The "C" pin is connected to the "-" pin to prevent
spurious piezoelectric element detection and the "A"
pin is left unconnected.
Fig. 19 illustrates the operation with
piezoelectric and LED outputs. Here, the LED is driven
from the "A" pin and the piezoelectric element PE is
driven from the "B" and "C" pins.
Fig. 20 illustrates the operation with an LED
and external DC-powered output circuit. Here, the LED
is driven from the "B" pin. In this configuration the
"C" pin is connected to the "-" pin to prevent spurious
piezoelectric element detection and the "A" pin is used
to provide a constant DC voltage output to provide, or
cause to be provided, a supply voltage for the external
output circuit. According to an embodiment of the
invention, the external output circuit is a device
which plays a melody or sound effect, drives a motor or
vibrator, activates a relay, generates a radio signal
or infrared signal to a remote receiver, etc.
Fig. 20A illustrates operation with an
external DC-powered output circuit only. Here, the "B"
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pin is left unconnected in this configuration and that
as in the previous configuration, the "C" pin is
connected to the "-" pin to prevent spurious
piezoelectric element detection and output of the "A"
pin. furnishes a constant DC voltage output to provide,
or cause to be provided, a supply voltage for the
external output circuit. According to an embodiment of
the invention, the external output circuit is a device
which plays a melody or sound effect, drives a motor or
vibrator, activates a relay, generates a radio signal
or infrared signal to a remote receiver, etc.
A pin designated "+" is connected to the
positive supply voltage. A pin designated "-" is
connected to the negative supply voltage (or ground).
According to an embodiment of the invention, the
difference between the positive and negative supply
voltage is greater than 2 volts and less than 6 volts
(DC). Another embodiment provides for higher supply
voltage differences and yet another embodiment provides
for lower supply voltage differences.
In normal operating mode, an "R" pin provides
the sensing pulses to the external network 327. In a
Testl mode, this pin provides access to the most
significant output bit of a primary 15-bit counter to
verify operation of the ripple count function. In a
TEST2 mode, this pin provides a 32 kHz pulse train with
approximately a 50% duty cycle.
In normal operating mode and in TEST2 mode,
an "S" pin is the sense input from the external network
327. In TEST1 mode, this pin provides access to the
oscillator tank circuit.
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In normal operating mode, a "D" pin is tied
either to the pin "+" or the pin "-" prior to the
application of power to the chip. If this pin is
connected to the pin "-" when power is applied, all
detected alarm conditions are indicated by signaling on
the "A", "B", and/or "C" pins immediately following the
end of each sense pulse and the operation counter
function is inhibited. If this pin is connected to the
pin "+" when power is applied, then a 4 second
qualification timeout is observed prior to alarm
signaling on the outputs. If the alarm condition does
not persist throughout this qualification period, the
pending alarm is canceled. If the alarm condition does
persist throughout this period, alarm signaling appears
at the outputs when the qualification period expires
and the operation counter is incremented. If a falling
edge is provided to this input while in normal
operating mode, the chip enters the TEST1 mode, the
primary 15-bit counter is set to all ones, and the
clock input to the primary counter is disabled. A
second falling edge arms the primary counter to be
clocked by the next rising edge on this input. The next
rising edge causes the primary counter to "roll-over"
from all ones to all zeroes. The next falling edge
causes a reset to be delivered to the circuitry. The
fourth falling edge removes the reset and enables
subsequent rising edges on this pin D to clock the
primary counter directly. Additionally, the fourth
falling edge causes exit of the TEST1 mode and entry of
the TEST2 mode.
In normal operating mode, an "A" pin provides
either a light emitting diode (LED) drive signal or a
high level DC voltage (near supply voltage at the pin
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"+" dependent on loading) when an alarm condition is
sensed. If there is no alarm condition, pin A is in a
high-impedance state. In the TEST1 mode, this pin
provides access to the output of the on-chip oscillator
5 (64 kHz +/- 30~). In the TEST2 mode, pin A resumes its
normal function.
In normal operating mode, a "B" pin
immediately after the application of power, provides
the piezo sensing pulse. After the piezo sensing
10 function is completed, this pin provides either a piezo
drive signal or an LED drive signal when an alarm
condition is sensed. If there is no~alarm condition,
this pin is in a high-impedance state. Neither the
TEST1 mode nor TEST2 mode has any direct effect on the
15 function of pin B.
In normal operating mode,a "C" pin serves
immediately after the application of power, to route
the piezo element sensing signal to internal circuitry.
After the piezo sensing function is completed, this pin
20 provides a piezo drive signal when an alarm condition
is sensed (only if the presence of a piezo element was
sensed between the "C" pin and the "B" pin). If direct
piezo drive is not to be used for a given circuit
arrangement, this pin should be tied to the "-" pin
25 which will assure that no piezo element is sensed.
Making this connection will also guarantee that the "C"
pin is permanently left in the high impedance state.
In Fig. 14, an analog section 1704 of the
chip 1700 provides all the bias and reference voltages
30 necessary for operation of the oscillator, power-on-
reset circuit and the Schmitt trigger functions as well
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as those functions themselves. Shortly after power is
applied between the "+" and "-" pins, the oscillator
function starts and the POR (power-on-reset) and OSC
signals are fed to a built-in test circuit block 1707.
Additionally, the analog section 1704 contains the
Schmitt trigger circuit which is used to convert the
analog signal present at the connection to the network
327 to discrete digital logic levels for sensing by the
sensor signal detector. An OSC signal comes from the
l0 micropower oscillator and has a nominal frequency of 64
kHz. A POR signal is a short pulse produced by a
monostable multivibrator.
A "D" Pin Capture flip-flop 1710 is clocked
by the POR signal shortly after power is applied and is
used to capture the power-up state of the "D" pin. The
output of this block is a signal called DELON. If DELON
is high following the POR pulse, then alarm
qualification counter 1714 and operation counter 1717
are enabled for subsequent alarm detection processing
and the LED blink rate is switched to 8 Hz during the
alarm qualification timeout period. If DELON is low
following the POR pulse, then the alarm qualification
counter 1714 and operation counter 1717 functions are
inhibited for subsequent alarm detection processing and
the LED blink rate is always 2 Hz when an alarm
condition is detected.
The built-in test circuit block 1707 controls
a primary 15-bit counter 1720 with set, reset, and
clock signal outputs based on activity on the "D" pin
subsequent to the end of the POR pulse. The TST1 output
from this block 1707 controls the signaling on the "A"
pin while in the TEST1 mode. It also controls the
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frequency and duty cycle of the signal output on the
"R" pin. The TST2 signal is used strictly to control
the test frequency multiplexes and, once asserted by
the fourth falling edge on the "D" pin as described
above, remains asserted until a full power off/on cycle
is detected.
The primary 15-bit counter 1720 provides all
of the key timing signals for chip operation. It is a
15-bit binary ripple counter which is normally clocked
at the nominal oscillator frequency of 64 kHz. In the
TEST1 mode, it can be manipulated by various
transitions on the "D" pin (see "D" pin description
above). In the TEST2 mode, it is clocked by the signal
present on the "D" pin.
A test frequency multiplexes 1724 is a 9-wide
2-to-1 multiplexes. Eighteen inputs are fed by various
outputs of the primary counter 1720. Nine outputs are
timing signals used for sense signal generation and
detection, LED blink rate, piezo detection, piezo tone
generation, and alarm qualification counter timeouts.
This block is controlled by the TST2 signal which is
generally used to increase the various frequencies for
manufacturing test purposes (to decrease test times).
A sensor signal generator 1727 receives
timing from the primary counter 1720 via the test
frequency multiplexes 1724 (32 Hz and 32 kHz) and an
enable signal from a piezo presence sensor block 1730.
When the piezo presence sensing function is completed,
the piezo presence sensor block 1730 produces the
GOSENSOR signal. This signal enables the signal
generator 1727 to produce a sensing signal whose
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frequency is nominally 32 Hz (64,000 divided by 2~°)
and whose duty cycle is 0.050. The SENSE OUT output of
this block is the signal on the "R" pin. The SAMPLE
output of this block is used to provide a synchronous
sampling clock to a sensor signal detector 1734.
The sensor signal detector 1734 is reset at
power-up time. Once the sensing function is enabled (by
assertion of the GOSENSOR signal), the connection to
network 327 is fed to the Schmitt trigger in the analog
section (to convert the analog voltage present there to
a discrete digital level) and the converted digital
level is sensed by this block when the SAMPLE signal is
asserted by the sensor signal generator. The SAMPLE
signal is asserted simultaneously with the end of the
sensing pulse.
The chip 1700 provides a non-alarm condition
feature. If the signal present at the connection to the
circuit 1727 was above the upper (supply-voltage-
tracking) threshold of the Schmitt trigger circuit,
then the ALARM output signal of this block is not
asserted and the ALARM RESET output signal is asserted.
The ALARM_RESET signal inhibits the alarm qualification
counter 1714 from counting which, in turn, prevents any
clocking signals from reaching the operation counter
1717.
The chip 1700 provides alarm condition with
delay and count feature. If the signal present at the
connection to the network 327 was below the upper
(supply-voltage-tracking) threshold of the Schmitt
trigger circuit, then the ALARM output signal of sensor
signal detector block 1734 is asserted and the
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ALARM RESET signal is not asserted. If the DELON signal
is high ("D" pin high when power was applied), then the
alarm qualification counter circuit 1714 is enabled to
begin the qualification delay and the LED blinker
circuit sets the LEDALARM signal high and generates an
8 Hz signal on LEDFLASH. When the qualification timeout
has ended, the signals QUALIFIED and QUALMUX are
asserted. The QUALIFIED signal is used to increment the
operation counter 1717 and change the LEDFLASH signal
from 8 Hz to 2 Hz (except for last operation). The
QUALMUX signal is used to satisfy several logic
equations relating to the usage of the outputs
dependent largely on whether a piezo was detected
between pins "B" and "C" following the application of
power.
The chip provides an alarm condition without
delay and count feature. If the signal present at the
connection to the network 327 was below the upper
(supply-voltage-tracking) threshold of the Schmitt
trigger circuit, then the ALARM output signal of block
1734 is asserted and the ALARM RESET signal is not
asserted. If the DELON signal is low ("D" pin low when
power applied) then the alarm qualification counter
1714 remains disabled and the LED blinker circuit sets
the LEDALARM signal high and generates a 2 Hz signal on
LEDFLASH. The QUALIFIED signal is never asserted so the
operation counter never increments. The QUALMUX signal
is used to satisfy several logic equations relating to
the usage of the outputs dependent largely on whether a
piezo was detected between pins "B" and "C" following
the application of power.
The chip 1700 provides an end-of-alarm
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condition feature. As soon as the voltage present at
the connection to the network 327 is found to have
returned above the upper (supply-voltage-tracking)
threshold of the Schmitt trigger circuit, then the
5 ALARM output signal of the block 1734 is de-asserted
and the ALARM_RESET signal is asserted. All alarm
activity stops and the outputs return to a high
impedance state.
An LED blinker circuit 1737 has several
10 inputs. The ALARM signal activates the basic function.
The DELON, QUALIFIED, and LASTOP signals control the
output frequency of a LEDFLASH signal. The frequency
and pulse-width control timing signals which define the
shape of the LEDFLASH signal are provided from the
15 primary counter via the test frequency multiplexer
(ALL TIMING). An LEDALARM signal is asserted (primary
operand in logic equation to generate LEDFLASH)
whenever an alarm condition exists and either: (a) the
delay and count feature is enabled and the operation
20 counter has not reached its terminal count, or, (b) the
delay and count feature is disabled.
A piezo tone generator 1740 also has several
inputs. The basic tone references (2 kHz, 4 kHz, and
the 2 Hz warble control) are provided by the primary
25 counter via the test frequency multiplexer. The actual
signal (ALTONE) to be generated from these basic inputs
is controlled by the LASTOP signal from the operation
counter. The time during an alarm condition at which
the ALTONE signal is allowed to drive the outputs is
30 controlled by the QUALMUX output from the alarm
qualification counter.
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The generator 1740 produces a warbling tone
when an alarm condition occurs and either: (a) the
delay and count feature is disabled, or, (b) the delay
and count feature is enabled and the current operation
cycle is not the last operation. Under either of these
conditions, the ALTONE signal is a fairly symmetrical
square wave which is modulated between 2 kHz and 4 kHz
at 2 Hz.
The generator 1740 also produces a Last Tone
signal when an alarm condition occurs and the delay and
count feature is enabled and the operation counter has
reached its terminal count. The ALTONE signal is a
fairly symmetrical square wave at a constant frequency
of 4 kHz .
The piezo presence sensor 1730 is enabled
immediately after power is applied to the chip. The
activation signal is provided by the primary counter
via the test frequency multiplexer. When this signal is
asserted, the PZSENSE output of this block produces a
single high-going pulse which causes the "B" pin
control circuits to transfer this pulse to the "B" pin
itself. During this pulse interval, the "C" pin output
is disabled. If a piezoelectric buzzer is connected
between pins "B" and "C" at this time, the pulse is
capacitively coupled from the "B" pin to the "C" pin
since a piezoelectric buzzer is electrically equivalent
to a small capacitor. The presence or absence of this
pulse (PZOIN) is then sampled by the block 1730. If the
piezo was present, then the PIEZO signal is asserted.
Otherwise, the PIEZO signal is not asserted. In either
case, when the sampling is completed the GOSENSOR
signal is asserted which, in turn, enables the sensor
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signal generator to begin transmitting the SENSE OUT
pulses and generating the SAMPLE signal to the sensor
signal detector. It should be noted that devices other
than piezoelectric buzzers may be used to form a
connection between the "B" and "C" pins as long as the
impedance is suitably low, say, below 1 million ohms.
The alarm qualification counter 1714 provides
the delay portion of the delay and count function. Its
purpose is to impose a four second delay between the
detection of an alarm condition and the generation of
alarm-related output pin signals. This functional block
is activated when an alarm condition exists and the
DELON signal is asserted. When the timeout has expired
and the operation counter has not yet reached terminal
count, the QUALIFIED signal is asserted. This signal is
used to increment the operation counter 1717 by one
count (1 count = 1 operation) and to change the
LEDFLASH output of the LED blinker circuit 1737. When
this function is enabled LEDFLASH starts generating an
8 Hz signal as soon as an alarm condition is detected.
Once the alarm qualification timeout expires, LEDFLASH
changes its frequency from 4 Hz to 2 Hz as a result of
the assertion of the QUALIFIED signal. The assertion of
the QUALIFIED signal also causes the QUALMUX signal to
be asserted. The QUALMUX signal is used to satisfy
several logic equations relating to the usage of the
outputs, dependent largely on whether a piezo was
detected between pins "B" and "C" following the
application of power.
The operation counter 1717 counts the total
number of alarms which persist beyond the four-second
qualification timeout period. The purpose of this
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counter is related to diaper wetness sensing inasmuch
as the number of diapers in a package varies both from
product to product as well as from manufacturer to
manufacturer. Since for this application the product
utilizing the chip is invariably battery operated and
since the battery size for these products is selected
to provide optimum energy capacity for the size of the
package of diapers with which the product is shipped,
this functional block is used to inhibit the chip from
operating once the expected end of useful life of the
battery energy source is approached. The actual battery
life is difficult to predict since the power
consumption of the chip and related circuitry
fluctuates wildly (maybe more than 1000:1) between the
dormant (non-alarm) and active (alarm) states.
Variability in the duration of the alarm condition adds
further uncertainty to the prediction.
A block identified as "A" Pin Control Circuit
1744 determines the manner of signaling present on the
"A" pin during alarm conditions and while in the
different test modes. The active output signal level is
a high voltage level. In TEST1 Mode, the on-chip
oscillator signal appears on the "A" pin.
In TEST2 Mode, the "A" pin produces signals
equivalent to the signals described below, except that
the sensor signal generator duty cycle in this mode is
about 50°s.
When the "A" pin signals in the normal
operating mode, the "A" pin signaling has five
different formats which depend on:(a) whether or not
the delay and count function is enabled or, (b) if the
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39
delay and count function is enabled (regardless of
whether or not the current operation is the last
operation) or, (c) whether or not a piezoelectric
buzzer (or other suitable electrical connection) is
detected by the piezo presence sensor.
If the delay and count function is enabled
and a piezo was sensed and the operation counter has
not yet reached terminal count, the "A" pin produces an
8 Hz signal with a 31.25 ms active pulse width during
the first four seconds after the alarm condition is
detected. Once the four second delay expires, the "A"
pin signaling changes to a 2 Hz signal with a 31.25 ms
active pulse width. The low (about 6%) duty cycle is
used to reduce power consumption.
If the delay and count function is enabled
and a piezo was sensed and the operation counter has
reached terminal count, the "A" pin produces another
signal, for example, an 8 Hz signal with a 31.25 ms
active pulse width during the entire alarm condition.
If the delay and count function is enabled and a piezo
was not sensed, the "A" pin produces a high impedance
state during the first four seconds after the alarm
condition is detected. Once the four second delay
expires, the "A" pin produces another signal, for
example, a high voltage level approximating the
voltage on the "+" pin for light loads. If the delay
and count function is not enabled and a piezo was
sensed, the "A" pin produces another signal, for
example, a 2 Hz signal with a 31.25 ms active pulse
width during the entire alarm condition. If the delay
and count function is not enabled and a piezo was
sensed, the "A" pin produces another signal, for
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example, a high voltage level approximating the voltage
on the "+" pin for light loads.
A block 1747 identified as "B" Pin Control
Circuits determines the manner of signaling present on
5 the "B" pin during alarm conditions and while in the
different test modes. The active output voltage level
is a high level.
The B pin control circuits 1747 are involved
in piezo presence sensing. The block 1747 causes the
10 "B" pin, shortly after power is applied to the chip, to
sense the presence or absence of a connection between
the "B" pin and the "C" pin. This involves generation
of a single pulse of approximately 32 ms within
approximately the first 100 ms of chip operation.
15 In the TEST1 Mode, the block 1747 produces
signals on the "B" pin largely equivalent to the
signaling cases described below except the sensor
signal generator duty cycle in this mode is about 50%
In the TEST2 Mode the block 1747 applies signals on the
20 "B" pin largely equivalent to the signaling cases
described below except that the sensor signal generator
duty cycle in this mode is about 50%.
In the normal operating mode the block 1747
applies signals on the "B" pin with six different
25 formats which depend on:(a) whether or not the delay
and count function is enabled or, (b) if the delay and
count function is enabled (regardless of whether or not
the current operation is the last operation) or, (c)
whether or not a piezoelectric buzzer (or other
30 suitable electrical connection) is detected by the
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41
piezo presence sensor.
If the delay and count function is enabled
and a piezo was not sensed and the operation counter
has not yet reached terminal count, block 1747
constrains the "B" pin to produce an 8 Hz signal with a
31.25 ms active pulse width during the first four
seconds after the alarm condition is detected. Once the
four second delay expires, the block 1747 causes the
"B" pin signaling to change to another signal, for
example, a 2 Hz signal with a 31.25 ms active pulse
width. If the delay and count function is enabled and a
piezo was not sensed and the operation counter has
reached terminal count, the block 1747 causes the "B"
pin to produce another signal, for example, an 8 Hz
signal with a 31.25 ms active pulse width, during the
entire alarm condition. If the delay and count function
is not enabled and a piezo was not sensed, the block
1747 causes the "B" pin to produce another signal, for
example, a 2 Hz signal with a 31.25 ms active pulse
width, during the entire alarm condition.
If the delay and count function is enabled and a piezo
was sensed and the operation counter has not yet
reached terminal count, the block 1747 causes the "B"
pin to exhibit a high impedance state during the first
four seconds after the alarm condition is detected.
Once the four second delay expires, the block 1747
causes the "B" pin to produce a "warbling" signal which
switches back and forth from 2 kHz to 4 kHz at a 2 Hz
rate.
If the delay and count function is enabled
and a piezo was sensed and the operation counter is at
its terminal count, the block 1747 causes the "B" pin
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to produce a constant 4 kHz signal with an
approximately square shape for the entire duration of
the alarm condition. If the delay and count function is
not enabled and a piezo was sensed, the block 1747
causes the "B" pin to produce a "warbling" signal which
switches back and forth from 2 kHz to 4 kHz at a 2 Hz
rate.
A block 1750 designated as "C" Pin Control
Circuits determines the manner of signaling present on
the "C" pin during alarm conditions and while in the
different test modes.
The block 1750 is involved in piezo presence
sensing. As described, the block 1750 causes the "C"
pin, shortly after power is applied to the chip, to
sense the presence or absence of a connection between
the "B" pin and the "C" pin. During this interval, the
"C" pin serves as an input. In an embodiment of the
invention, to prevent a piezo from being sensed, this
pin is grounded during this interval.
In TEST1 Mode, the block 1750 causes the "C"
pin to produce signals largely equivalent to the
signaling cases described below except that the sensor
signal generator duty cycle in this mode is about 50~.
In TEST2 Mode, the block 1750 causes the "C"
pin to produce signals largely equivalent to the
signaling cases described below except that the sensor
signal generator duty cycle in this mode is about 50~.
In the normal operating mode, the block 1750
causes the "C" pin to produce three different
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signalling formats that depend on:(a) whether or not
the delay and count function is enabled or, (b) if the
delay and count function is enabled (regardless of
whether or not the current operation is the last
operation) or, (c) whether or not a piezoelectric
buzzer (or other suitable electrical connection) is
detected by the piezo presence sensor.
If the delay and count function is enabled
and a piezo was sensed and the operation counter has
not yet reached terminal count, the block 1750 causes
the "C" pin to exhibit a high impedance state during
the first four seconds after the alarm condition is
detected. Once the four second delay expires, the block
1750 causes the "C" pin to produce another signal, for
example, a "warbling" signal which switches back and
forth from 2 kHz to 4 kHz at a 2 Hz rate. If the delay
and count function is enabled and a piezo is sensed
and the operation counter is at its terminal count, the
block 1750 causes the "C" pin to produce another
signal, for example, a high impedance state for the
first 4 seconds of the alarm condition followed by a
constant 4 kHz signal with an approximately square
shape, for the remainder of the alarm condition. If the
delay and count function is not enabled and a piezo was
sensed, the block 1750 causes the "C" pin to produce a
"warbling" signal that switches back and forth from 2
kHz to 4 kHz at a 2 Hz rate.
Figs. 21A to 40 illustrate other embodiments
of the invention. In the exploded perspective view of
Fig. 21A, a disposable diaper 2100 includes an inner
sheet 2104 of a water-permeable film, generally known
and hereinafter referred to as cover stock 2104, that
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overlies a wetness absorber layer 2107 of highly
liquid-absorbent padding or other highly absorbent
material, generally known and hereinafter referred to
as the core 2107. In one embodiment the core 2107 may
include granules or filaments of water-retentive
polymer, such as polyacrylic acid. An outer,
electrically insulating plastic film that is
impermeable to liquid water, generally known and
hereinafter referred to as the backing sheet 2110,
l0 supports two conductive spaced-apart electrodes 2114,
in the form of metallic or other electrically-
conductive strips, with low surface area, hereinafter
referred to as the sensing electrodes 2114, that extend
along the center of the backing sheet 2110. The
backing sheet 2110 also supports a tissue 2108 and a
barrier 2109. According to embodiments of the
invention, the sensing electrodes 2114 electrically
contact the core 2107, or the tissue 2108, or the
barrier 2109. According to an embodiment of the
invention, the sensing electrodes 2114 pass
longitudinally through the core 2107. According to
another embodiment, sensing electrodes 2114 project
along the interior surface of the backing sheet 2110 in
contact with the core 2107. According to another
embodiment, the sensing electrodes 2114 are in the form
of conductive filaments, threads or wires.
The sensing electrodes are connected
electrically to widened conductive areas 2117,
hereinafter referred to as coupling electrodes 2117,
that serve to couple signals between the sensing
electrodes 2114 and a detector module that is to be
placed against the outer surface of the backing sheet
2110. The detector module is provided with pickup
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electrodes each of which couples non-conductively, for
example capacitively, to respective coupling electrodes
2117.
An optional tissue layer 2108 may be in
5 contact with the core 2107, that serves to distribute
wetness more quickly and uniformly about the core 2107,
and that also serves to bring wetness from core 2107
into close contact with sensing electrodes 2114.
An optional wetness barrier layer 2109 may be
10 interposed between a portion of the sensing electrodes
2114 and the core 2107 or the tissue 2108, that may
serve to prevent wetness in the core 2107 from reaching
a defined portion of the sensing electrodes 2114. If
barrier layer 2109 is soluble in water, the effect will
15 be a delay before wetness reaches the covered portion
of the sensing electrodes 2114. If barrier layer 2109
is not soluble in water, the effect will be a
requirement that the wetness in the core 2107 reaches
beyond the covered portion of the sensing electrodes
20 2114 before the wetness may be detected.
Pocket slip 2112 is bonded to backing sheet
2110 along all but one of its edges to as to form the
pocket 2111. The pocket 2111 is positioned so that
when a detector module is placed therein, the pickup
25 electrodes in the pocket 2111 are registered opposite
the coupling electrodes 2117. The bonded area of
pocket slip 2112 is identified with cross-hatching. If
pocket slip 2112 is composed of material that is
resilient, then insertion of an item that is slightly
30 larger than the relaxed size of the pocket 2111 into
the pocket 2111 will deform the unbonded portion of
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46
pocket slip 2112, which will tend to hold such an
inserted item snugly in place and apply tension to the
area of backing sheet 2110 located beneath the unbonded
portion of pocket slip 2112. If pocket slip 2112 is
composed of an inelastic material, then the same
tension and secure insertion may be obtained by a
combination of deformation of the backing sheet 2110
and deformation of the inserted item itself. According
to one embodiment, one pair of the coupling electrodes
2117 and one pocket 2111 is located near either the
front or the rear waistband of the diaper 2100, and in
another embodiment, a separate set of these aspects is
located near both waistbands.
In the exploded perspective view of Fig. 218,
a disposable diaper 2100 includes a sensor carrier
layer 2119, onto which the sensing electrodes 2114 and
coupling electrodes 2117 may be printed or otherwise
pre-assembled prior to assembly onto backing sheet
2110.
Figs. 22A, 22B, 22C, and 22D show four
possible arrangements of sensing and coupling
electrodes 2114 and 2117. These represent repeated
patterns that are to be parted at the separation line
2140. The separation line 2140 may correspond to the
place where the diapers 2100 made in the machine
direction are separated from one another near the end
of the production line, or where sets of electrodes
2114 and 2117 that are printed or otherwise pre-
assembled onto a carrier layer are separated prior to
placement onto the backing sheet 2110, or the
separation line 2140 may simply be conceptual, where
electrodes 2114 and 2117 are assembled repeatedly onto
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......... . _.~._._ ~.~....~.. .._.._._ ~ , , t
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a diaper that is made in the cross-direction.
In Fig. 22A, sensing electrodes 2114 are
discontinuous, and there are two pair of coupling
electrodes 2117 for each pair of sensing electrodes
2114. This provides a pair of coupling electrodes near
each waistband. In Fig. 22B, sensing electrodes 2114
are also discontinuous, but there is one pair of
coupling electrodes 2117 for each pair of sensing
electrodes 2114. This provides a pair of coupling
ZO electrodes near only one waistband. In Fig. 22C,
sensing electrodes 2114 are continuous, and there are
two pair of coupling electrodes 2117 for each pair of
sensing electrodes 2114. This provides a pair of
coupling electrodes near each waistband. In Fig. 22D,
sensing electrodes 2114 are also continuous, but there
is one pair of coupling electrodes 2117 for each pair
of sensing electrodes 2114. This provides a pair of
coupling electrodes near only one waistband.
The sensing electrodes 2114 may be filaments,
wires, yarn, ribbon, foil, fabric or film made from
conductive material. The sensing electrodes 2114 may
be filaments, yarn, ribbon, fabric or film that bears
conductive filler material, that is coated with
conductive material, or with surfaces subjected to a
conversion process or suffused with a material that
renders said surfaces conductive. The sensing
electrodes 2114 may be in the form of yarn that
includes continuous or discontinuous lengths of
conductive filament or wire, that is wrapped with
conductive filament or wire, that is infused with
material that is conductive, or that is infused with
material that bears conductive filler material. The
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48
sensing electrodes 2114 may be liquid or plastic
material that is conductive or that bears conductive
filler material, such as a thermoplastic, wax, paste,
gel, latex, adhesive, or ink, that may be selectively
applied onto a surface or into an absorbent matrix by
methods such as printing, rolling, or extrusion.
Sensing electrodes 2114 may be formed by the
selective conversion or suffusion of portions of a
surface of a film, fabric or tissue material by a
process that renders said portions conductive. Sensing
electrodes 2114 may be formed by the selective removal
of continuous conductive coating or converted outer
layer from surface of a film material such as by
abrasion or photolithography to render multiple
isolated conductive areas (electrodes) from a
continuous piece of coated film. Sensing electrodes
2114 may be formed by the selective removal of portions
of an electrode film, fabric or tissue material such as
by die-cutting to render multiple isolated conductive
elements (electrodes) from a continuous element of
coated film, fabric or tissue material.
Sensing electrodes 2114 may be redundant, in
that each of the two electrodes that make up a pair may
have more than one strand, ribbon, strip, etc., and
that these redundant elements may be of different
morphologies.
The coupling electrodes 2117 may be ribbon,
foil, fabric, tissue or film made from conductive
material. The coupling electrodes 2117 may be ribbon,
fabric, tissue or film that bears conductive filler
material, that is coated or infused with conductive
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49
material, or with surfaces subjected to a conversion
process or suffused with a material that renders said
surfaces conductive. The coupling electrodes 2117 may
be ribbon, fabric, tissue or film material that is
conductive or has one or both surfaces made conductive,
where said structure is optically transparent or
translucent. The coupling electrodes 2117 may be
liquid or plastic material that is conductive or that
bears conductive filler material, such as a
thermoplastic, wax, paste, gel, latex, adhesive, or
ink, that may be selectively applied onto a surface or
into an absorbent matrix by methods such as printing,
rolling, or extrusion.
The coupling electrodes 2117 may be formed by
the selective conversion or suffusion of portions of a
surface of a film, fabric or tissue material by a
process that renders said portions conductive. The
coupling electrodes 2117 may be formed by the selective
coating of portions of a surface of a film, fabric or
tissue material with conductive material, such as by
sputtering or thermal vapor deposition. The coupling
electrodes 2117 may be formed by the selective removal
of continuous conductive coating or converted outer
layer from surface of a film material to render
multiple electrodes from a continuous piece of coated
film. The coupling electrodes 2117 may be formed by the
selective removal of portions of an electrode film,
fabric or tissue material such as by die-cutting to
render multiple electrode elements from a continuous
element of coated film.
Figs. 23A and 23B depict two embodiments of
an electrode arrangement where a plurality of
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individual electrodes 2314 and 2317 may function
together to effectively form pairs of electrodes
corresponding to sensing electrodes 2114 and coupling
electrodes 2117 in Figs. 21A and 21B and 22A to 22D.
5 In Fig. 23A, the electrodes are of uniform width, where
the portions of these electrodes that are to function
as the coupling electrodes 2317 are the portions that
are located in coupling area 2316. In Fig. 23B, the
sensing electrodes 2314 are narrower than coupling
10 electrodes 2317. The arrangement of the electrodes
into a plurality of parallel elements serves to provide
great immunity to translational variation in the
registration between the pocket 2111 and the coupling
electrodes 2317.
15 Figs. 24, 25, and 26 depict three possible
construction schemes pertaining to the placement of the
electrodes relative to the other layers in the diaper
2100. Each figure is an elevation that cuts across a
single coupling electrode 2117 in a direction
20 orthogonal to the sensing electrode 2114, and that
includes all layers but the pocket 2111. These are
simplified to the extent that certain adhesive
applications and other typical or possible processes
are not depicted, and no indication is given as to the
25 treatment of the various layers as they exist beyo:3
the boundaries of the drawn area.
In Fig. 24, the backing sheet 2110 has been
sprayed with the construction adhesive 2133, has had
the sensing electrode 2114 laid down into the
30 construction adhesive 2133, has had the coupling
electrode 2117, which is oriented so that the
conductive coating 2118 is facing the sensing electrode
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r ~ _ . __.
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51
2114, nipped down against the sensing electrode 2114,
has had the tissue 2108 nipped down over both
electrodes 2114 and 2117, has had the core 2107 nipped
down over the tissue 2108, and finally had the cover
2107 nipped down over the core 2107.
An electrically conductive liquid, paste,
putty, or powdered solid material may be deposited in
the gap 2130 in contact with the sensing electrode and
the coupling electrode.
Fig. 25 differs from Fig. 24 only in that
barrier layer 2119 is added between tissue 2208 and
sensing and coupling electrodes 2114 and 2117.
In Fig. 26, the side of the sensing electrode
2114 that bears the adhesive 2135 has been nipped down
to the backing sheet 2110, and the side with the
conductive coating 2118 faces outward. The tissue 2108
has been sprayed with the construction adhesive 2133,
and the sensing electrode 2114 has been laid down into
the construction adhesive 2133 in the tissue 2108,
whereupon the tissue 2108 bearing the sensing
electrodes 2114 has been nipped down to the backing
sheet 2100 that bears the coupling electrodes 2117.
This places the conductive coating 2118 on the coupling
electrodes 2117 in contact with sensing electrodes
2114. The core 2107 is nipped down onto the existing
structure, and ultimately the cover 2104 is nipped down
over this.
An electrically conductive liquid, paste,
putty, or powdered solid material may be deposited in
the gap 2130 in contact with the sensing electrode and
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the coupling electrode.
Figs. 27 and 28 depict two possible
arrangements of sensing and coupling electrodes 2114
and 2117 where they are incorporated into the core
2104. In both cases, sensing and coupling electrodes
2114 and 2117 are printed or otherwise pre-assembled
onto a carrier layer 2119, and placed within the core
2104, with the ends bearing coupling electrodes 2117
protruding from its ends. In Fig. 27, the coupling
electrodes 2117 are to be assembled to the backing
sheet 2110 in an area near the waistband that is clear
of the core 2104. In Fig. 28, the portion of carrier
2119 that bears the coupling electrodes 2117 is folded
back over the core and is therefor located beneath the
core in the finished diaper 2100.
In another embodiment, unsupported sensing
electrodes 2114 are laid into the core 2107, and the
coupling electrodes are brought down over them as in
Fig. 24.
Fig. 29 is a detail of the pocket 2111 bonded
to the backing sheet 2110, showing the bonded area
around all but one edge of the pocket slip 2112.
Fig. 30 is the same as Fig. 29, except that
one method of reinforcement of the unbonded edge of
pocket 2111 is illustrated, where the edge that is not
to be bonded to the backing sheet 2110 is folded over
on itself one or more times and bonded to itself prior
to or concurrent with the bonding of the pocket 2111 to
the backing sheet 2110. In another embodiment, the
open edge of the pocket 2111 is reinforced by bonding a
SUBSTITUTE SHEET (RULE 26)
._u_.~~..~....~..~~_"...m ~,... , ,
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separate strip of material to it.
Fig. 31 depicts the folding of the carrier
strip 2119 bearing electrodes 2114 and 2117 so as to
shorten its length. The Z-fold can be placed into the
material as it is being assembled onto the diaper 2100,
or prior to assembly.
Fig. 32 depicts an apparatus for abrading the
conductive coating 2118 from the carrier strip 2119.
Here, the rubber wheel 2210 rotates so that it rubs the
carrier strip 2119 counter to its direction of travel.
Fig. 33 depicts an apparatus for applying the
sensing electrodes 2114 into the construction adhesive
2133 on the backing sheet 2110. Reels of wire 3305 are
fitted with appropriate feed, braking and anti-run-on
means. Sensing electrodes 2114 in the form of wires
take one or more turns around tensioning drums 3310,
thread through direction control pins 3315, and are
drawn onto backing sheet web 2110 by the motion of said
web. Also depicted for clarity are pockets 2111, and
frontal tape 2102. The backing sheet passes over a
drum 3320.
Fig. 34 depicts an apparatus for removing the
non-conductive fibers from the core of a yarn 3414 that
has been spun-wrapped with wire to form an electrode
2114. Gaseous fuel source 3405 feeds gas to burner
3415. Gas flow modulator 3410 is connected in parallel
with gas source 3405. Ignition source 3420 may ignite
flame 3417. The yarn 3414 is drawn through the space
directly over the flame, and the flame is modulated so
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that it vaporizes, melts, or partially vaporizes and
partially melts the non-conductive fibers in the core
of the yarn. The resultant segments of bare wire can
make improved contact with conductive surfaces, such as
coupling electrodes 2117.
Fig. 35 illustrates an example of a module
3504 having pickup electrodes 3507 in the pocket 2111
formed by the pocket slip 2112 on the backing sheet
2110. The pickup electrodes 3507 are positioned
opposite, and are here non-conductively and
capacitively coupled to, the coupling electrodes 2117
across the backing sheet 2110. Thicknesses are
exaggerated for clarity.
Figs. 36 and 37 depict a portion of an
embodiment of the backing sheet 2110 in the form a
typical two-component cloth-like sheet 2110, composed
of a non-woven fabric layer 2110A and a film layer
2110B, and containing a rectangular treated portion
3613. The treated portion 3613 includes a monolithic
matrix of the non-woven fabric layer 2110A and the film
layer 2110B. The treatment serves to increase the
dielectric constant and decrease the thickness of the
treated portion 3513, and to render it more amenable to
later bonding of the pocket material. The treatment of
the portion 3613 may be accomplished thermally or
ultrasonically, but the preferred method is ultrasonic.
In Fig. 36, the treated portion 3613 is
located centrally and near the front of the waistband,
as indicated by the presence of the frontal tape 2102.
According to other embodiments the treated area is
alternatively or additionally located near the rear
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waistband or on another part of the diaper. For a
given diaper construction, the position of the treated
portion 3613 will tend to coincide with that of the
pocket 2111 that is shown in various other figures.
5 Fig. 37 show the fibers of the backing sheet
non-woven layer 2110A separate from and randomly
oriented over the backing sheet film layer 21108,
except in the treated portion 3613. There, the two
materials are shown combined into a monolithic matrix.
10 In addition to backing sheet film 21108, the
embedding encapsulant, according to embodiments of the
invention, includes another material added to either
side of the portion 3613 prior to treatment. This
additional material may be a thermoplastic film that is
15 compatible with the backing sheet film 21108, or it may
be some other material that could serve the purpose of
increasing the fraction of solid thermoplastic
available to encapsulate the fibers of the non-woven
backing sheet layer 2110A.
20 Fig. 38 depicts the basics of an ultrasonic
apparatus for performing the treatment of the portion
3613. The backing sheet 2110 is conveyed continuously
on the roll 3855 with the non-woven layer 2110B
typically facing the ultrasonic horn 3850. The
25 ultrasonic horn 3850 is powered periodically, so that
it supplies energy across its width to the backing
sheet 2110 for uniform time periods at uniform time
intervals. This is done to assure that uniform lengths
of a narrow portion of the overall width of the backing
30 sheet 2110 are subjected to treatment at uniform
spatial intervals. According to an embodiment of the
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invention, a rotary horn is used as an alternative to a
stationary horn in order to eliminate the risk of the
backing sheet 2110 becoming snagged on the horn.
In each of the embodiments of Figs. 21A to
38, the diapers are made by forming each of the
components of the figures, for example the components
2104, 2107, 2110, 2111, 2112, 2114, and 2117,
assembling the components with suitable adhesives or
other adhering means to achieve the arrangements shown,
l0 and then shaping them to the typical diaper shape. The
order in which the components are formed or assembled
may vary with the needs of the manufacturer.
A general manufacturing process may involve
forming a liquid-impermeable backing sheet having an
exterior surface and an interior surface so as to
produce an exterior of the diaper and an interior of
the diaper, forming a liquid-absorbing arrangement and
placing the liquid-absorbing arrangement next to the
backing sheet, forming an elastic pocket and bonding
the pocket to the exterior surface of the backing sheet
to contain a detector module, forming sensing
electrodes and placing sensing electrodes within the
interior of the diaper and within the interior surface
of the backing sheet in contact with the liquid
absorbing arrangement in a direction to extend opposite
the elastic pocket so as to allow the sensing
electrodes to couple capacitively to the detector
module, assembling the various components by bonding,
and forming the product into the shape of a diaper.
The bonding of any component may occur at any phase of
the process.
SUBSTITUTE SHEET (RULE 26)
r._ . _. . ,w"~".,.w.,w .. _ ..... _ _.._..,~,._ . , , r
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Each of the elements formed and assembled are
constructed to achieve the structure described for each
of the figures and as described below. The process is
finished by configuring the assembly into a diaper
shape and adding elastics at the waist and legs and
fastening strips 2130 to produce the diaper of Fig. 39.
According to embodiments of the invention,
diapers are manufactured by automatic machine where
component materials are supplied from rolls or other
sources located at points in the line. In one example,
the backing sheet runs as a web through the full length
of the manufacturing line up to the point where the
individual diapers are separated from one another.
However, the backing sheet may be put in sheets. The
other components are affixed continuously,
individually, or in partially pre-assembled
combinations upon the backing sheet 2110. In an
exemplary machine direction assembly operation, at a
point where the backing sheet web is fed in, the
frontal tape is cut and placed onto the outer side of
the backing sheet 2110, and the pocket 2111 is cut and
bonded in place onto the outer side of the backing
sheet 2110. Adhesive is applied onto the area where
the coupling electrodes 2117 are to be placed, the
sensing electrodes 2114 are fed in, the coupling
electrodes 2117 are cut and placed, construction
adhesive is applied to the entire surface, leg and
waistband elastics are applied, and an absorbent pad
2107 that was formed off line is carried between a web
of tissue layer 2109 and cover stock 2104 and fed in
and affixed, and the backing sheet 2110 is cut to shape
so as to narrow the crotch. Finally, the individual
diapers are cut apart, separated, folded, and bagged.
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The order of these steps may change as desired.
An example of an automatic machine appears in
Fig. 40. Here, a manufacturing line 4101 receives a
web of material that forms the backing sheet, either
pre-formed or uncut, from a backing sheet web source
4104. The line 4101 either moves the pre-formed
backing sheets along the line or cuts the web to form
the backing sheets. A liquid-absorber layer source
4107 supplies the components of the liquid-absorber
layer, either individually or as a unit, either pre-
formed or as linear sheets, to the line 4101. The line
4101 bonds the liquid-absorbing arrangement to the
backing sheet made from the web. An elastic pocket
source 4110 supplies an elastic pocket, pre-formed or
uncut, to the line 4101 and the latter bonds the
elastic pocket to the backing sheet made from the web.
A sensing electrode source 4114 supplies sensing
electrodes, in partially or completely shaped
condition, to the line 4101 and the latter bonds them
in the proper position in contact with the liquid-
absorbing arrangement and opposite the pocket. An
elastic source 4117 furnishes elastic to the line 4101,
and the latter adds the elastic, and cuts and shapes
the diapers into the state shown in Fig. 39. The line
4101 also separates, folds, and bags the diapers.
According to various embodiments of the invention, each
of the sources 4104, 4107, 4110, 4114, and 4117 assume
different positions so that the order of processing may
vary. The bonding may occur at phases of the process
other than those shown. Also any one of the sources
4104, 4107, 4110, 4114, and 4117 may supply pre-formed
or partially formed materials, and the line 4101 uses
these material. Where the sources furnish incomplete
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or partially formed components, the line 4101
constructs the material into final forms.
According to embodiments of the invention, the sensing
electrodes are made as any one or more of the
following:
filament, wire, yarn, ribbon, foil, fabric or film
made from conductive material
filament, yarn, ribbon, fabric or film that bears
conductive filler material, that is coated with
conductive material, or with surfaces subjected to
a conversion process or suffused with a material
that renders said surfaces conductive
yarn that includes continuous or discontinuous
lengths of conductive filament or wire, that is
wrapped with conductive filament or wire, that is
infused with material that is conductive, or that
is infused with material that bears conductive
filler material
liquid or plastic material that is conductive or
that bears conductive filler material, such as a
thermoplastic, wax, paste, gel, latex, adhesive, or
ink, that may be selectively applied onto a surface
or into an absorbent matrix by methods such as
printing, rolling, or extrusion
selective conversion or suffusion of portions of a
surface of a film, fabric or tissue material by a
process that renders said portions conductive
selective removal of continuous conductive coating
or converted outer layer from surface of a film
material such as by abrasion or photolithography to
render multiple isolated conductive areas
(electrodes) from a continuous piece of coated film
selective removal of portions of an electrode film,
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fabric or tissue material such as by die-cutting to
render multiple isolated conductive elements
(electrodes) from a continuous element of coated
film, fabric or tissue material
5 electrodes may be in the form of a plurality of
stripes
each electrode may consist of a plurality of
conductors.
According to embodiments of the invention, the
10 attachment of the electrodes involves doing any one
or more of the following:
selective coating or application of conductive
material onto portions of a surface of a film,
fabric or tissue material where said surface may
15 be the backing sheet or where said film, fabric or
tissue material may be subsequently applied onto
said backing sheet
incorporation into pad, tissue, or other component
layer such as by weaving or laminating.
According to embodiments of the invention, the coupling
electrodes are made as any one or more of the
following:
ribbon, foil, fabric, tissue or film made from
conductive material
ribbon, fabric, tissue or film that bears conductive
filler material, that is coated or infused with
conductive material, or with surfaces subjected to
a conversion process or suffused with a material
that renders said surfaces conductive
ribbon, fabric, tissue or film material that is
conductive or has one or both surfaces made
conductive, where said structure is optically
SUBSTITUTE SHEET (RULE 26)
a__ .. . ....._~..~.._.~. _.~ _..... .. ..f _. .. r , r
~..
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transparent or translucent
liquid or plastic material that is conductive or
that bears conductive filler material, such as a
thermoplastic, wax, paste, gel, latex, adhesive, or
ink, that may be selectively applied onto a surface
or into an absorbent matrix by methods such as
printing, rolling, or extrusion
selective conversion or suffusion of portions of a
surface of a film, fabric or tissue material by a
process that renders said portions conductive
selective coating of portions of a surface of a
film, fabric or tissue material with conductive
material, such as by sputtering or thermal vapor
deposition
selective removal of continuous conductive coating
or converted outer layer from surface of a film
material to render multiple electrodes from a
continuous piece of coated film
selective removal of portions of an electrode film,
fabric or tissue material such as by die-cutting to
render multiple electrode elements from a
continuous element of coated film
electrodes may be in the form of a plurality of
stripes.
According to an embodiment of the invention, connection
of each coupling electrode to each sensing electrode
are made as one or more of the following:
connection formed by conductive adhesive that is
printed, transferred, thermally bonded or otherwise
applied to the coupling electrode, the sensing
electrode, or to another surface to which the
electrodes are to be bonded
connection formed by physical contact, where sensing
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electrode is interposed between a coupling
electrode and another surface, where a non-
conductive adhesive is applied to said other
surface that holds said coupling electrode to said
other surface
connection optionally enhanced by presence of an
electrically conductive liquid, paste, putty, or
powdered solid material in contact with the
sensing electrode and the coupling electrode
According to an embodiment of the invention, combined
sensing and coupling electrodes are made as one or
more of the following:
electrode pattern deposited or pre-assembled onto a
carrier film, fabric or tissue, where pattern may
be repeated continuously on a roll of material,
either in the machine or cross directions, and
where pattern may consist of pairs of sensing
electrodes with coupling electrodes at one or both
ends
when printed, the ink used for the sensing
electrodes and the coupling electrodes may have
different conductivity's
electrodes that are uniform in width along their
entire length
where diminished sensitivity to conditions
external to the diaper may be attained by the
placement of the electrodes so that one or more
layers of dielectric material are interposed
between the portion that will perform the
sensing function and the backsheet
where the electrodes may be in the form of a
plurality of stripes
SUBSTITUTE SHEET (RULE 28)
4..ro..~.,..,..__...._.. r _. , , t
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According to an embodiment of the invention,
the pocket involves making it in one or more of the
following ways:
composed of an elastomeric or plastomeric, solid or
foamed, film or fabric material to retain a
substantially non-deformable item, or a
substantially inelastic film or fabric material to
retain a spring-loaded deformable item
transparent or opaque
printing
with or without
superficial or sub-surface
formed by bonding a relatively small patch of
material along all but one of its edges
directly to the backsheet
to the bondable surface of a secondary patch of
material, such as a label or frontal tape, that
is applied to the backsheet
reinforcement of the open edge by rolling and self-
bonding an edge of the patch of material that will
become the open edge prior to bonding onto a diaper
or secondary patch of material
reinforcement of the open edge by bonding a strip of
reinforcing material to an edge of the patch of
material that will become the open edge prior to
bonding onto a diaper backsheet or secondary patch
of material
printing
on transparent material, forming a portion of a
graphic that is completed or changed when the
pocket is occupied by an object bearing a
corresponding graphic
acts to obscure a view of the electrodes from the
exterior of a diaper
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According to embodiments of the invention, the
attachment of the pocket to the backsheet involves any
one or more of the following steps:
direct thermal or ultrasonic bonding;
thermoplastic or thermosetting adhesive bonding
adhesive as coextruded skin on pocket material,
selectively bonded,
adhesive selectively printed on pocket
material: allows selective bonding by heating
full area,
adhesive film co-laminated with pocket,
selectively bonded
adhesive printed or sprayed onto pocket
material and selectively bonded;
bond directly to backsheet
backsheet may be printed
forming a portion of a graphic that is
completed or changed when the pocket is
occupied by an object bearing a
corresponding graphic,
acting to obscure a view of the electrodes
from the exterior of a diaper;
bond to a label that is applied to the backsheet
label may be variously opaque to obscure view
of electrodes,
variously opaque material,
variously opaque coating on transparent or
variously opaque material,
label may be printed
forming a portion of a graphic that is
completed or changed when the pocket is
occupied by an object bearing a
corresponding graphic,
acting to obscure a view of the electrodes
SUBSTITUTE SHEET (RULE 26)
~...m~._~._... _..~..~.y...._u... ......... ... _ .... ~.
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from the exterior of a diaper;
deformable module with a generally non-deformable
pocket to achieve retention and tension;
side levers on module
5 actuate one or more switches,
retain one or more batteries,
provide tensile force against sides of pocket.
According to embodiments of the invention, the control
mechanisms operate any one or more of the following
10 ways:
interposition of a layer of water barrier film
between the sensing electrodes and the absorbent
material in the vicinity of the urine discharge
area to prevent wetness from reaching said
15 electrodes until the core is to some degree
saturated;
interposition of a layer of water-soluble, water
barrier film between the sensing electrodes and the
absorbent material to impart a time delay prior to
20 when wetness reaches the sensing electrodes;
alteration of the length or the spacing or both the
length and spacing of the sensing electrodes to
alter the degree to which the core must be
saturated and the speed with which wetness reaches
25 said electrodes.
According to embodiments of the invention, the
structures and orientations involve assembling the
components to achieve any one or more of the following
sequences:
30 backsheet/construction adhesive/sensing electrode/
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PCT/US97/08405
film coupling electrode/core
backsheet/PSA/sensing electrode/ film coupling
electrode/core
backsheet/construction adhesive/sensing electrode/
film coupling electrode/tissue/core
backsheet/PSA/sensing electrode/ film coupling
electrode/tissue/core
backsheet/PSA/film coupling electrode/sensing
electrode/construction adhesive/tissue
backsheet/printed coupling electrode/sensing
electrode/construction adhesive/tissue
According to embodiments of the invention, the methods
for manufacture involve any one or more of the
following steps:
adjustment of the length of combined sensing and
coupling electrodes to match various diaper
lengths, where said combined electrodes are first
deposited or pre-assembled onto a carrier film,
fabric or tissue with coupling electrodes at both
ends, said length adjustment executed by imparting
a double fold, generally known as a Z-fold, across
the carrier film, such as during or proximal to the
process of cutting and placing the combined
electrodes onto a diaper backsheet
clear a swath in the conductive coating on the
coupling electrode material to render multiple
electrodes from a continuous piece of coated film
using abrasion
rotating frictive wheel, such as of rubber
rotating abrasive wheel, such as of grit-coated
aluminum
rotating wire or fiber wheel, such as of brass
or polyester
one or more blade edges, oriented so as to
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.~ . .._ _ ... ..r , , ,
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scrape rather than slice the material surface
using an electrical arc
using a beam of light, such as from a laser
incorporate coupling electrodes into a diaper by
unwinding electrode material from a roll or spool
where coupling electrode material is slit, cut and
placed
where electrode material may bear a coating of
conductive adhesive
where another layer to which the coupling
electrode is being applied may bear a coating of
adhesive
where the adhesive may be pressure-sensitive or
thermally activated, transparent or variously
opaque
incorporate coupling electrodes into a diaper by
printing conductive ink onto backsheet
incorporate sensing electrodes into a diaper by
unwinding electrode material continuously in-line
with the backsheet in the case of diapers that are
made in the machine direction
where the electrode material is affixed to the
backing sheet
by laying it onto open construction adhesive
previously applied to the backsheet
by laying it onto the backsheet and keeping it
in tension before the construction adhesive is
applied
where the sensing electrodes are severed between
diapers
by the same blade or blades that separate the
diapers from one another
by an electric current applied to a relatively
short span of the sensing electrodes by knife
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edges in the region of the waistband
incorporate sensing electrodes into a diaper by
cutting and placing lengths of electrode material
where the electrode material is affixed to the
backing sheet
by laying it onto open construction adhesive
previously applied to the backsheet
by laying it onto the backsheet and keeping it
in tension before the construction adhesive is
applied
where the lengths of electrode material are cut to
length using one or more blades, water jets,
flames, or beams of light, such as from a laser
remove the non-conductive fibers from segments of a
continuous yarn containing or wrapped with one or
more conductive fibers or wires
by application of a flame
where the flame height and intensity is
modulated
by direct modulation of the gas flow
where the flow rate modulation is effected
by control of a valuing orifice plumbed
in series with the gas flow
where the flow rate modulation is effected
by the motion of a piston in a cylinder
or a diaphragm in a cavity that has a
single inlet plumbed in parallel with the
gas flow
by modulation of the flow velocity of a
cross-flowing jet of air
by modulation of the flow into a cross-
oriented vacuum inlet
by a combination of the above
where the flame is interrupted periodically by
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a perforated solid or mesh disk, while
optionally the gas flow is simultaneously
modulated
where the flame is intermittently applied by
moving the gas nozzle, while optionally the
gas flow is simultaneously modulated
by application of a jet of hot air (with similar
approaches to modulation or interruption)
by application of a modulated beam of light, such
as from a laser
by application of a jet of water where the jet is
intermittently applied by moving the nozzle,
while optionally modulating the flow
simultaneously.
According to embodiments of the invention, the coating
materials involve incorporating one or more of the
following:
metals for optically dense, electrically conductive
coating, such as Ni, NiCr, Ni over A1, Sn
semiconductive oxides to create an optically
transparent, electrically conductive coating, such
as ITO, ATO, Zn0
multiple layers incorporating both metals and oxides
to create an optically transparent, electrically
conductive coating, such as A1203/Ag/ITO
According to embodiments of the invention, the
electrode materials are made as, or in any one or
more of the following ways:
fabric made electrically conductive by impregnation
with one or more salts that remain wet, and
therefore ionic and conductive, due to the
hygroscopic nature of the mixture, such as of
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calcium chloride and sodium chloride, or lithium
chloride and sodium chloride
electrically conductive putty composed of a mixture
of an electrically conductive filler and an oil
5 base, optionally made stickier by the addition of
one or more tackifiers, such as rosin.
According to other embodiments of the invention, the
other aspects of the structure or method involve one
or more of the following means or steps:
14 coat surface of item to be placed into pocket with
slippery coating, such as wax
coat interior surfaces of pocket with slippery
material, such as silicone oil.
While embodiments of the invention have been
25 described in detail it will be evident to those skilled
in the art that the invention may be embodied otherwise
without departing from its spirit and scope.
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