Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 1 of 8 PageID# 18862
`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 1 of 8 Page|D# 18862
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`EXHIBIT 5
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`EXHIBIT 5
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`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 2 of 8 PageID# 18863
`11111111111111111111111111111111111111111111111111111111111111111111111111
`5,134,886
`Aug. 4, 1992
`
`United States Patent [19]
`Ball
`
`US005134886A
`[11] Patent Number:
`[45] Date of Patent:
`
`[54]
`
`[76]
`
`CAPACITIVE PRESSURE TRANSDUCER
`FOR USE IN RESPIRATOR APPARATUS
`
`Inventor: Kenneth H. Ball, 30003 Via Victoria,
`Rancho Palos Verdes, Calif. 90274
`
`[21] Appl. No.: 685,687
`
`[22] Filed:
`
`Apr. 16, 1991
`
`[51] Int. CI.5 GOlL 9/12
`[52] U.S. CI. 73/718; 128/204.23;
`128/716; 361/283
`73/718, 724; 361/283;
`128/204.23, 204.26, 716, 722
`
`[58] Field of Search
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`5,052,400 10/1991 Dietz
`
`128/722
`
`Primary Examiner—Donald 0. Woodiel
`Attorney, Agent, or Firm—Edward A. Sokolski
`
`ABSTRACT
`[57]
`An electrically conductive diaphragm is sandwiched
`
`between a first and second board member. One of said
`board members has a metallic plate thereon, there being
`a non conductive spacer having an opening therein
`separating such board member from the diaphragm.
`The board members, diaphragm and spacer are joined
`together to form an integral assembly, the portion of the
`diaphragm opposite the opening in the spacer being free
`to move in such opening towards the board member
`with the metallic plate, motion of the diaphragm away
`from the spacer being prevented by the other board
`member. A respiratory gas inlet is provided through the
`board member with the metallic plate to the opening in
`the spacer. The diaphragm and metallic plate form a
`capacitor the capacitance of which is varied in response
`to the pressure differential between the gas inlet and the
`atmosphere, the diaphragm only being free to move
`towards the metallic plate in response to negative pres-
`sures (suction) induced during inspiration by a patient.
`
`10 Claims, 3 Drawing Sheets
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`
`RJ RE DVA_001485459
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 3 of 8 PageID# 18864
`U.S. Patent
`5,134,886
`
`Aug. 4, 1992
`
`Sheet 1 of 3
`
`FIG. IA
`
`FIG. 113
`
`EXPIRATION
`
`TINE
`
`INSPIRATION
`
`PRESSURE INPUT
`
`CAPAC ITANCE
`
`EXPIRATION INSPIRATION
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`EXPIRATION INSPIRATION
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`FIG. IC
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`
`RJ RE DVA_001485460
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`

`

`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 4 of 8 PageID# 18865
`U.S. Patent
`5,134,886
`
`Aug. 4, 1992
`
`Sheet 2 of 3
`
`i
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`FIG. 2
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`11
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`
`RJ RE DVA_001485461
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`

`

`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 5 of 8 PageID# 18866
`U.S. Patent
`5,134,886
`
`Sheet 3 of 3
`
`Aug. 4, 1992
`
`190
`
`—
`
`21b
`
`fB
`
`32
`
`D. C.
`OUTPUT
`
`FIG.4
`
`14
`
`CARRIER
`WAVE
`G ENERATOR
`
`FIG. 5D
`
`V /
`
`FIG.5E
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`
`FIG. 5A
`
`FIG. 58
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`4
`
` INSPIRATION
`
`FIG. 5C
`
`RJ RE DVA_001485462
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`

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`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 6 of 8 PageID# 18867
`5,134,886
`
`1
`
`CAPACITIVE PRESSURE TRANSDUCER FOR USE
`IN RESPIRATOR APPARATUS
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`This invention relates to capacitive pressure trans-
`ducers and more to such a transducer for use in respira-
`tor apparatus which provides an electrical control sig-
`nal for controlling the supply of a gas such as oxygen to
`a patient in response to the inspiratory breathing cycles
`of such patient.
`2. Description of the Related Art
`Respiratory Apparatus has been developed in the
`prior art which responds to the breathing cycles of the
`patient and supplies oxygen in response to such breath-
`ing cycles. In such devices, the breathing cycles are
`generally sensed by a pressure transducer which pro-
`vides an electrical output in accordance with such
`breathing. Such an apparatus is described in U.S. Pat.
`No. 4,612,928 issued Sep. 23, 1986 to Tiep et al. Other
`such devices are described in the various references
`cited in the Tiep patent. The pressure transducers em-
`ployed in such prior art devices generally operate in
`response to both the inspiration and expiration of the
`patient. As oxygen is to be supplied only in accordance
`with the inspiration demand of the patient, the expira-
`tion input is extraneous and it has been found tends to
`decrease the accuracy of the control signal for effecting
`the oxygen supply. This is particularly significant in the
`case of capacitive transducers in view of the fact that
`the diaphragm forming one of the capacitive plates of
`the transducer is driven in response to the expiration of
`the breathing cycle away from its neutral position and
`may return late to such position such that it will be seen
`by the system as an inspiration.
`
`BRIEF SUMMARY OF THE INVENTION
`The transducer of the present invention overcomes
`the aforementioned shortcomings of the prior art by
`employing a structure in which an electrical output is
`only provided in response to the inspiration cycles of
`the patient. Such structure comprises an electrically
`conductive diaphragm which is sandwiched between
`first and second board members. The first board mem-
`ber has a metal plate thereon which forms one of the
`plates of a capacitor, the other of the capacitor plates
`being formed by the diaphragm. A spacer board having
`an opening in the central portion thereof is placed be-
`tween the diaphragm and the first board member such
`that the diaphragm is free to move axially in such open-
`ing towards and away from the first board member. The
`surface of the diaphragm opposite the second board
`member is mounted flush thereagainst with the entire
`diaphragm including the central portion thereof flat
`against the second board member. The various elements
`of the transducer are held together in a flat integrated
`unit by means of adhesive layers placed therebetween,
`the flexible diaphragm being held flat in its neutral posi-
`tion by such adhesive layers.
`An inlet is provided through the first board member
`for receiving the respiratory pressure signal. The dia-
`phragm is drawn towards the metal plate of the first
`board member in response to the inspiration cycles of
`the respiration. The diaphragm is, however, restrained
`against movement away from such plate by the second
`board member during the exhalation pressure inputs. A
`second metal plate is formed on the first board member
`
`2
`which is electrically insulated from the first plate and
`which forms a fixed capacitor with the non-moving
`portions of the diaphgragm, thus effectively providing
`an electrical connection to the diaphragm.
`5 The capacitor formed by the transducer is connected
`in an electrical circuit in series with an oscillatory volt-
`age such that the amplitude of such voltage is varied
`(modulated) in accordance with the inspiration breath-
`ing cycles, this in view of the change of capacitance and
`10 capacitive reactance in response to pressure changes
`induced by the inspiration cycles of the breathing of the
`patient.
`It is therefore an object of this invention to provide a
`more accurate pressure transducer for use in a respira-
`15 tor system.
`It is another object of this invention to provide a
`capacitive pressure transducer for use in a respirator
`system which responds only to the inspiration breathing
`cycles.
`20 Other objects of the invention will become apparent
`from the following description in connection with the
`accompanying drawings.
`
`25
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a graphic illustration of the respiratory
`pressure input generated by breathing;
`FIG. 1B is a graphic illustration of the operation of
`prior art transducers;
`30 FIG. 1C is a graphic illustration of the operation of
`the transducer of the present invention;
`FIG. 2 is an exploded perspective view of a preferred
`embodiment of the invention;
`FIG. 3 is an exploded elevational view in cross sec-
`tion of the preferred embodiment;
`FIG. 3A is a cross sectional view of the preferred
`embodiment;
`FIG. 4 is an electrical schematic drawing illustrating
`the operation of the transducer of the invention; and
`40 FIG. 5A-5E are a series of waveforms related to the
`drawing of FIG. 4.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`45 Referring now to FIGS. 1A-1C, waveforms illustrat-
`ing the operation of the invention are shown. FIG. 1A
`shows the pressure input to a pressure transducer in
`response to the breathing of a patient. As can be seen,
`the variation in pressure is approximately sinusoidal
`50 with the inspiration portions of the breathing cycle
`producing a negative pressure (suction) and the expira-
`tion portions of the breathing cycle producing a posi-
`tive pressure.
`Referring now to FIG. 1B, the variations in capaci-
`55 tance produced in response to the breathing cycles
`shown in FIG. 1A in a prior art pressure transducer are
`shown. As can be seen, the capacitance of the trans-
`ducer output increases in response to inspiration and
`decreases in response to expiration. It is to be noted that
`60 this prior art transducer employs an electrically con-
`ductive diaphragm responsive to the breathing cycles
`which is drawn closer to a fixed conductive plate during
`inspiration and driven away from this fixed plate during
`expiration, the diaphragm and plate forming the plates
`65 of a capacitor.
`Referring now to FIG. 1C, the operation of the in-
`vention is illustrated. As can be seen, the device of the
`invention responds only to the inspiration cycles and
`
`RJ RE DVA_001485463
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`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 7 of 8 PageID# 18868
`
`5,134,886
`
`3
`not to the expiration cycles. Thus, there is a transducer
`output reflecting an increase in capacitance and lower-
`ing of capacitive reactance only in response to the pa-
`tient's inspiration. This, as pointed out above, enables
`the provision of a much more desirable supply of oxy-
`gen (or other gas) to the patient.
`Referring now to FIGS. 2, 3 and 3A, a preferred
`embodiment of the invention is shown. Top board 11
`which is of an electrically insulative material has a metal
`disc ha formed on the center of the undersurface
`thereof, this end result typically being achieved by em-
`ploying a copper clad printed circuit board for board 11
`and etching away all but the disk portion. A vent hole
`llb is formed through board 11 and disk ha to maintain
`the top of diaphragm at atmospheric pressure. Adhesive
`layer 12 is placed between the undersurface of board 11
`and diaphragm 14. Layer 12, which may be formed
`from no.9491 adhesive available from Minnesota Min-
`ing and Manufacturing Co., has a central circular aper-
`ture 12a formed therein which has the same diameter as
`apertures 18a and 22a. Adhesive layer 12 has the same
`thickness as disk 11a(typically of the order of 0.002
`inches). Adhesive layer 12 thus acts as both a spacer and
`a binder for joining the diaphragm 14 to board 11.
`Spacer member 17 has an aperture 17a formed in the
`center thereof which is approximately the same diame-
`ter as that of disk ha (typically 1.1 inches). Spacer
`member 17 which is made of an electrically insulative
`material such as a polycarbonate plastic typically has a
`thickness of about 0.01 inches. Spacer member 17 is
`bound to the underside of diaphragm 14 by means of
`adhesive layer 18 which may be of the same material
`and thickness as adhesive layer 12. Adhesive layer 18
`has a circular aperture 18a formed in the central portion
`thereof which mates with the aperture 17a of spacer 17.
`Diaphragm 14 is carefully installed between the oppos-
`ing adhesive layers to assure that it lies flat therebe-
`tween. The diaphragm is of a non conductive plastic
`material such as polycarbonate with a thickness which
`is typically about 0.0005 inches. The top surface of the
`diaphragm which faces top board 11 is metalized with a
`material such a nickel to provide one of the plates of the
`capacitor of the transducer.
`Bottom board 19 is a printed circuit board similar to
`top board 11. The copper cladding of this board is
`etched to form central disk 19a and outer plate 19b with
`a circular space 19c therebetween. An aperture 20
`which runs through board 19 and disk 19a is provided
`and a pressure inlet tube 25 for receiving the breathing
`pressure of a patient is installed in this aperture. An
`electrical connector 21 is attached to board 19, this
`connector having a pair of electrical leads 21a and 21b
`which are connected to disk 19a and outer plate 19b,
`respectively. Board 19 is bound to spacer 17 by means
`of adhesive layer 22 which is similar to adhesive layers
`12 and 18 and has a circular aperture 22a formed in the
`central portion thereof.
`It is to be noted that while in the preferred embodi-
`ment the device of the invention utilized flat boards,
`which are joined together by means of adhesive layers,
`the device can also be fabricated using sheets of electri-
`cally insulative material which are joined together by
`screws, rivets or other fastening means.
`Referring now to FIGS. 4 and 5, an electrical circuit
`for generating a control signal from the output of the
`transducer of the invention is shown along with wave-
`forms generated in such circuit. .
`
`4
`The output of carrier wave generator 30 which may
`be a square wave generator and typically has a fre-
`quency of 200-600 kiloHz is fed to plate 19b of the
`transducer. A fixed capacitance appears between plate
`5 19b and the opposing portions of diaphragm 14. This
`capacitance couples the output of the square wave gen-
`erator to the diaphragm. A variable capacitor is formed
`between the disk 19a and the opposing central portions
`of the diaphragm. The central portions of the dia-
`l() phragm are free to move towards disk 19a in the cavity
`17a formed in spacer 17. The diaphragm is prevented
`from moving from its center position towards plate 11
`by metal disk ha and the opposing portions of adhesive
`layer 12. Thus, the diaphragm can only move in re-
`15 sponse to suction pressure as induced during inspiration
`and is prevented from moving away from its neutral
`position in response to expiration induced pressure.
`FIG. 5A schematically illustrates the square wave
`signal generated by generator 30 without there being
`20 any pressure input to the transducer to vary the capaci-
`tance of the capacitor formed between the diaphragm
`and disk 19a. FIG. 5B schematically illustrates a modu-
`lation or variation in amplitude of the square wave
`signal due to variations in the capacitance of the vari-
`25
`able capacitor in response to a breathing inspiration
`induced input pressure. The individual square waves, as
`shown in FIG. 5D are differentiated to form sharp
`pulses as shown in FIG. 5E. This differentiation is ef-
`30 fected by the differentiator formed by the fixed and
`variable capacitors and resistor 32. This differentiated
`signal has its negative going portions clipped by diode
`31, and this signal is integrated in the integration circuit
`formed by resistor 33 and capacitor 35 to provide a
`35 varying DC output "C" as shown in FIG. 5C.
`In this manner, a DC output signal is generated which
`is in accordance with the inspiration portions of the
`breathing cycle only and which has no output in re-
`sponse to expiration.
`40 While the invention has been described and illus-
`trated in detail, it is to be clearly understood that this is
`intended by way of illustration and example only and is
`not to be taken by way of limitation, the scope of the
`invention being limited only by the terms of the follow-
`45 ing claims.
`I claim:
`1. A capacitive pressure transducer for use in respira-
`tor apparatus comprising:
`first and second board members,
`50 a diaphragm having a conductive surface forming
`one of the plates of a capacitor, said diaphragm
`being mounted between said board members,
`said first board member having a conductive surface
`portion positioned opposite said diaphragm and
`forming the other of the plates of said capacitor,
`said diaphragm having a predetermined neutral
`position,
`means for restraining said diaphragm against move-
`ment from said neutral position away from said first
`board member,
`means for permitting movement of said diaphragm
`from said neutral position towards said first board
`member,
`means for joining said board members and said dia-
`phragm together to form an integral assembly, and
`inlet means for introducing a respirator pressure sig-
`nal through said first board member to said dia-
`phragm,
`
`55
`
`60
`
`65
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`Case 1:20-cv-00393-LO-TCB Document 729-3 Filed 06/16/21 Page 8 of 8 PageID# 18869
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`5,134,886
`
`6
`from said first member during expiration cycles of
`said respirator pressure signal and being permitted
`to move towards said first member during inspira-
`tion cycles of said respirator pressure signal,
`5 thereby providing a variation in capacitance be-
`tween the diaphragm and the conductive surface of
`said first member solely in accordance with said
`inspiration cycles.
`8. The capacitive pressure transducer of claim 7
`10 wherein the means for joining the members, the dia-
`phragm and the spacer means together comprises a first
`adhesive layer between said first member and said
`spacer means, a second adhesive layer between said
`spacer means and said diaphragm, and a third adhesive
`15 layer between said diaphragm and said second member.
`9. The capacitive pressure transducer of claim 7
`wherein said inlet means comprises a tube member ex-
`tending through said first board member to provide
`fluid communications to said diaphragm.
`20 10. A capacitive pressure transducer for use in respi-
`rator apparatus comprising:
`first and second members, each of said members hav-
`ing at least one substantially flat surface,
`a diaphragm having a conductive surface forming
`one of the plates of a capacitor, said diaphragm
`being mounted between the one flat surface of said
`members and having a predetermined neutral posi-
`tion,
`30 said first member having a conductive surface on said
`one flat surface thereof, said conductive surface
`being positioned opposite said diaphragm and
`forming the other of the plates of said capacitor,.
`spacer means having an opening therein mounted
`between the first member and the diaphragm,
`said one flat surface of the second member being
`mounted flush against said diaphragm so as to pre-
`vent motion of said diaphragm from said neutral
`position towards said second board member,
`40 said first member having a second conductive surface
`on said one flat surface thereof which is indepen-
`dent of said first mentioned conductive surface,
`said second conductive surface forming a fixed
`capacitor with the portions of said diaphragm
`which are not opposite the opening in said spacer
`means,
`means for joining said members, said diaphragm and
`said spacer means together to form an integral
`assembly, and
`50 inlet means for introducing a respiratory pressure
`signal through the first member to the opening in
`said spacer means, the diaphragm being in said
`neutral position restrained against movement away
`from said first member during expiration cycles of
`said respirator pressure signal and being permitted
`to move towards said first member during inspira-
`tion cycles of said respiratory pressure signal,
`thereby providing a variation in capacitance be-
`tween the diaphragm and the conductive surface of
`60 said first member solely in accordance with said
`inspiration cycles.
`* * * * *
`
`5
`the diaphragm being restrained from movement away
`from said first board member during the expiration
`cycles of said pressure signal and being permitted
`to move towards said first board member during
`inspiration cycles of said pressure signal, thereby
`providing a variation in capacitance between the
`diaphragm and the conductive surface of said first
`board member solely in accordance with said inspi-
`ration cycles.
`2. The capacitive pressure transducer of claim 1
`wherein said means for permitting movement of said
`diaphragm towards said first board member comprises a
`spacer board having an opening therein mounted be-
`tween the first board member and the diaphragm.
`3. The capacitive pressure transducer of claim 1
`wherein said means for restraining said diaphragm
`against movement away from said first board member
`comprises a surface of said second board member which
`is mounted flush against said diaphragm.
`4. The capacitive pressure transducer of claim 2
`wherein said means for restraining said diaphragm
`against movement away from said first board member
`comprises a surface of said second board member which
`is mounted flush against said diaphragm.
`5. The capacitive pressure transducer of claim 2
`wherein the means for joining the board members the
`diaphragm, and the spacer board together comprises a
`first adhesive layer between said first board member
`and said spacer board, a second adhesive layer between
`said spacer board and said diaphragm, and a third adhe-
`sive layer between said diaphragm and said second
`board member.
`6. The capacitive transducer of claim 1 wherein said
`inlet means comprises a tube member extending
`through said first board member to provide fluid com-
`munications to said diaphragm.
`7. A capacitive pressure transducer for use in respira-
`tor apparatus comprising:
`first and second members, each of said members hav-
`ing at least one substantially flat surface,
`a diaphragm having a conductive surface forming
`one of the plates of a capacitor, said diaphragm
`being mounted between the one flat surface of said
`members and having a predetermined neutral posi-
`tion,
`said first member having a conductive surface on said
`one flat surface thereof, said conductive surface
`being positioned opposite said diaphragm and
`forming the other of the plates of said capacitor,
`spacer means having an opening therein mounted
`between the first member and the diaphragm,
`said one flat surface of the second member being
`mounted flush against said diaphragm so as to pre-
`vent motion of said diaphragm from said neutral
`position towards said second board member,
`means for joining said members, said diaphragm and
`said spacer means together to form an integral
`assembly, and
`inlet means for introducing a respiratory pressure
`signal through the first member to the opening in
`said spacer means, the diaphragm being in said
`neutral position restrained against movement away
`
`25
`
`35
`
`45
`
`55
`
`65
`
`RJ RE DVA_001485465
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